diff --git a/build/Android.common.mk b/build/Android.common.mk
index 24bfe02..5dab0fd 100644
--- a/build/Android.common.mk
+++ b/build/Android.common.mk
@@ -37,12 +37,19 @@
 	src/dex_file.cc \
 	src/dex_instruction.cc \
 	src/dex_verifier.cc \
+	src/heap.cc \
 	src/jni_compiler.cc \
 	src/jni_internal.cc \
+	src/mark_stack.cc \
+	src/mark_sweep.cc \
 	src/memory_region.cc \
+	src/mspace.c \
 	src/object.cc \
+	src/object_bitmap.cc \
+	src/offsets.cc \
 	src/raw_dex_file.cc \
 	src/runtime.cc \
+	src/space.cc \
 	src/stringpiece.cc \
 	src/stringprintf.cc \
 	src/thread.cc
@@ -74,7 +81,8 @@
 	src/dex_instruction_visitor_test.cc \
 	src/jni_compiler_test.cc \
 	src/object_test.cc \
-	src/raw_dex_file_test.cc
+	src/raw_dex_file_test.cc \
+	src/space_test.cc
 
 TEST_TARGET_SRC_FILES := \
 	$(TEST_COMMON_SRC_FILES) \
diff --git a/build/Android.libart.host.mk b/build/Android.libart.host.mk
index 0cf87cf..92cc4da 100644
--- a/build/Android.libart.host.mk
+++ b/build/Android.libart.host.mk
@@ -20,7 +20,6 @@
 LOCAL_MODULE_TAGS := optional
 LOCAL_SRC_FILES := $(LIBART_HOST_SRC_FILES)
 LOCAL_CFLAGS := $(ART_CFLAGS)
-LOCAL_WHOLE_STATIC_LIBRARIES := libcutils
 LOCAL_SHARED_LIBRARIES := liblog libz-host
 LOCAL_LDLIBS := -ldl -lpthread -lrt
 include $(BUILD_HOST_SHARED_LIBRARY)
diff --git a/src/assembler.cc b/src/assembler.cc
index b5a34d9..52d424a 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -8,10 +8,6 @@
 
 namespace art {
 
-std::ostream& operator<<(std::ostream& os, const Offset& offs) {
-  return os << offs.Int32Value();
-}
-
 static byte* NewContents(size_t capacity) {
   byte* result = new byte[capacity];
 #if defined(DEBUG)
diff --git a/src/assembler.h b/src/assembler.h
index 84462c5..cc02c69 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -13,41 +13,6 @@
 class AssemblerBuffer;
 class AssemblerFixup;
 
-// Allow the meaning of offsets to be strongly typed
-class Offset {
- public:
-  explicit Offset(size_t val) : val_(val) {}
-  int32_t Int32Value() const {
-    return static_cast<int32_t>(val_);
-  }
-  uint32_t Uint32Value() const {
-    return static_cast<uint32_t>(val_);
-  }
- protected:
-  size_t val_;
-};
-std::ostream& operator<<(std::ostream& os, const Offset& offs);
-
-// Offsets relative to the current frame
-class FrameOffset : public Offset {
- public:
-  explicit FrameOffset(size_t val) : Offset(val) {}
-  bool operator>(FrameOffset other) const { return val_ > other.val_; }
-  bool operator<(FrameOffset other) const { return val_ < other.val_; }
-};
-
-// Offsets relative to the current running thread
-class ThreadOffset : public Offset {
- public:
-  explicit ThreadOffset(size_t val) : Offset(val) {}
-};
-
-// Offsets relative to an object
-class MemberOffset : public Offset {
- public:
-  explicit MemberOffset(size_t val) : Offset(val) {}
-};
-
 class Label {
  public:
   Label() : position_(0) {}
diff --git a/src/assembler_arm.cc b/src/assembler_arm.cc
index a519e35..603be68 100644
--- a/src/assembler_arm.cc
+++ b/src/assembler_arm.cc
@@ -2,6 +2,7 @@
 
 #include "src/assembler.h"
 #include "src/logging.h"
+#include "src/offsets.h"
 #include "src/utils.h"
 
 namespace art {
diff --git a/src/assembler_arm.h b/src/assembler_arm.h
index 4fb061f..3981f4a 100644
--- a/src/assembler_arm.h
+++ b/src/assembler_arm.h
@@ -6,6 +6,7 @@
 #include "src/constants.h"
 #include "src/managed_register.h"
 #include "src/logging.h"
+#include "src/offsets.h"
 #include "src/utils.h"
 
 namespace art {
diff --git a/src/assembler_x86.cc b/src/assembler_x86.cc
index 35e6129..2b21463 100644
--- a/src/assembler_x86.cc
+++ b/src/assembler_x86.cc
@@ -1,10 +1,10 @@
 // Copyright 2011 Google Inc. All Rights Reserved.
 
-#include <string.h>
 #include "src/assembler.h"
 #include "src/casts.h"
 #include "src/globals.h"
 #include "src/memory_region.h"
+#include "src/offsets.h"
 
 namespace art {
 
diff --git a/src/assembler_x86.h b/src/assembler_x86.h
index 85cc50b..a32191f 100644
--- a/src/assembler_x86.h
+++ b/src/assembler_x86.h
@@ -3,12 +3,12 @@
 #ifndef ART_SRC_ASSEMBLER_X86_H_
 #define ART_SRC_ASSEMBLER_X86_H_
 
-#include <stdint.h>
-#include <string.h>
 #include "src/assembler.h"
 #include "src/constants.h"
+#include "src/globals.h"
 #include "src/managed_register.h"
 #include "src/macros.h"
+#include "src/offsets.h"
 #include "src/utils.h"
 
 namespace art {
@@ -172,7 +172,7 @@
     }
   }
 
-  static Address Absolute(const uword addr) {
+  static Address Absolute(uword addr) {
     Address result;
     result.SetModRM(0, EBP);
     result.SetDisp32(addr);
diff --git a/src/class_linker.cc b/src/class_linker.cc
index ff5bc81..6fac610 100644
--- a/src/class_linker.cc
+++ b/src/class_linker.cc
@@ -29,7 +29,7 @@
 void ClassLinker::Init() {
   // Allocate and partially initialize the Class, Object, Field, Method classes.
   // Initialization will be completed when the definitions are loaded.
-  java_lang_Class_ = reinterpret_cast<Class*>(Heap::AllocRaw(sizeof(Class), NULL));
+  java_lang_Class_ = down_cast<Class*>(Heap::AllocObject(NULL, sizeof(Class)));
   CHECK(java_lang_Class_ != NULL);
   java_lang_Class_->descriptor_ = "Ljava/lang/Class;";
   java_lang_Class_->object_size_ = sizeof(Class);
@@ -83,15 +83,18 @@
 }
 
 StaticField* ClassLinker::AllocStaticField() {
-  return reinterpret_cast<StaticField*>(Heap::AllocRaw(sizeof(StaticField), java_lang_ref_Field_));
+  return down_cast<StaticField*>(Heap::AllocObject(java_lang_ref_Field_,
+                                                   sizeof(StaticField)));
 }
 
 InstanceField* ClassLinker::AllocInstanceField() {
-  return reinterpret_cast<InstanceField*>(Heap::AllocRaw(sizeof(InstanceField), java_lang_ref_Field_));
+  return down_cast<InstanceField*>(Heap::AllocObject(java_lang_ref_Field_,
+                                                     sizeof(InstanceField)));
 }
 
 Method* ClassLinker::AllocMethod() {
-  return reinterpret_cast<Method*>(Heap::AllocRaw(sizeof(Method), java_lang_ref_Method_));
+  return down_cast<Method*>(Heap::AllocObject(java_lang_ref_Method_,
+                                              sizeof(Method)));
 }
 
 Class* ClassLinker::FindClass(const StringPiece& descriptor,
@@ -215,8 +218,8 @@
   klass->super_class_ = NULL;
   klass->super_class_idx_ = class_def.superclass_idx_;
 
-  klass->num_sfields_ = header.static_fields_size_;
-  klass->num_ifields_ = header.instance_fields_size_;
+  klass->num_static_fields_ = header.static_fields_size_;
+  klass->num_instance_fields_ = header.instance_fields_size_;
   klass->num_direct_methods_ = header.direct_methods_size_;
   klass->num_virtual_methods_ = header.virtual_methods_size_;
 
@@ -226,11 +229,11 @@
   LoadInterfaces(class_def, klass);
 
   // Load static fields.
-  if (klass->num_sfields_ != 0) {
+  if (klass->NumStaticFields() != 0) {
     // TODO: allocate on the object heap.
     klass->sfields_ = new StaticField*[klass->NumStaticFields()]();
     uint32_t last_idx = 0;
-    for (size_t i = 0; i < klass->num_sfields_; ++i) {
+    for (size_t i = 0; i < klass->NumStaticFields(); ++i) {
       RawDexFile::Field raw_field;
       raw->dexReadClassDataField(&class_data, &raw_field, &last_idx);
       StaticField* sfield = AllocStaticField();
@@ -599,8 +602,8 @@
       if (!DexVerify::VerifyClass(klass)) {
         LG << "Verification failed";  // TODO: ThrowVerifyError
         Object* exception = self->GetException();
-        klass->SetObjectAt(OFFSETOF_MEMBER(Class, verify_error_class_),
-                           exception->GetClass());
+        size_t field_offset = OFFSETOF_MEMBER(Class, verify_error_class_);
+        klass->SetFieldObject(field_offset, exception->GetClass());
         klass->SetStatus(Class::kStatusError);
         return false;
       }
@@ -1190,12 +1193,11 @@
     field_offset = OFFSETOF_MEMBER(DataObject, fields_);
   }
   // Move references to the front.
-  klass->num_reference_ifields_ = 0;
+  klass->num_reference_instance_fields_ = 0;
   size_t i = 0;
   for ( ; i < klass->NumInstanceFields(); i++) {
     InstanceField* pField = klass->GetInstanceField(i);
     char c = pField->GetType();
-
     if (c != '[' && c != 'L') {
       for (size_t j = klass->NumInstanceFields() - 1; j > i; j--) {
         InstanceField* refField = klass->GetInstanceField(j);
@@ -1205,12 +1207,12 @@
           klass->SetInstanceField(j, pField);
           pField = refField;
           c = rc;
-          klass->num_reference_ifields_++;
+          klass->num_reference_instance_fields_++;
           break;
         }
       }
     } else {
-      klass->num_reference_ifields_++;
+      klass->num_reference_instance_fields_++;
     }
     if (c != '[' && c != 'L') {
       break;
@@ -1380,11 +1382,14 @@
   return NULL;
 }
 
-String* ClassLinker::ResolveString(const Class* referring, uint32_t string_idx) {
+String* ClassLinker::ResolveString(const Class* referring,
+                                   uint32_t string_idx) {
   const RawDexFile* raw = referring->GetDexFile()->GetRaw();
   const RawDexFile::StringId& string_id = raw->GetStringId(string_idx);
   const char* string_data = raw->GetStringData(string_id);
-  String* new_string = Heap::AllocStringFromModifiedUtf8(java_lang_String_, char_array_class_, string_data);
+  String* new_string = Heap::AllocStringFromModifiedUtf8(java_lang_String_,
+                                                         char_array_class_,
+                                                         string_data);
   // TODO: intern the new string
   referring->GetDexFile()->SetResolvedString(new_string, string_idx);
   return new_string;
diff --git a/src/common_test.h b/src/common_test.h
index ee22cb6..bb82d19 100644
--- a/src/common_test.h
+++ b/src/common_test.h
@@ -1,6 +1,7 @@
 // Copyright 2011 Google Inc. All Rights Reserved.
 
 #include "src/base64.h"
+#include "src/heap.h"
 #include "src/thread.h"
 #include "src/dex_file.h"
 
@@ -27,6 +28,11 @@
   virtual void SetUp() {
     ASSERT_TRUE(Thread::Init());
     ASSERT_TRUE(Thread::Attach() != NULL);
+    ASSERT_TRUE(Heap::Init());
+  }
+
+  virtual void TearDown() {
+    Heap::Destroy();
   }
 };
 
diff --git a/src/dlmalloc.c b/src/dlmalloc.c
new file mode 100644
index 0000000..e366ec9
--- /dev/null
+++ b/src/dlmalloc.c
@@ -0,0 +1,5454 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+/*
+  This is a version (aka dlmalloc) of malloc/free/realloc written by
+  Doug Lea and released to the public domain, as explained at
+  http://creativecommons.org/licenses/publicdomain.  Send questions,
+  comments, complaints, performance data, etc to dl@cs.oswego.edu
+
+* Version 2.8.3 Thu Sep 22 11:16:15 2005  Doug Lea  (dl at gee)
+
+   Note: There may be an updated version of this malloc obtainable at
+           ftp://gee.cs.oswego.edu/pub/misc/malloc.c
+         Check before installing!
+
+* Quickstart
+
+  This library is all in one file to simplify the most common usage:
+  ftp it, compile it (-O3), and link it into another program. All of
+  the compile-time options default to reasonable values for use on
+  most platforms.  You might later want to step through various
+  compile-time and dynamic tuning options.
+
+  For convenience, an include file for code using this malloc is at:
+     ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.3.h
+  You don't really need this .h file unless you call functions not
+  defined in your system include files.  The .h file contains only the
+  excerpts from this file needed for using this malloc on ANSI C/C++
+  systems, so long as you haven't changed compile-time options about
+  naming and tuning parameters.  If you do, then you can create your
+  own malloc.h that does include all settings by cutting at the point
+  indicated below. Note that you may already by default be using a C
+  library containing a malloc that is based on some version of this
+  malloc (for example in linux). You might still want to use the one
+  in this file to customize settings or to avoid overheads associated
+  with library versions.
+
+* Vital statistics:
+
+  Supported pointer/size_t representation:       4 or 8 bytes
+       size_t MUST be an unsigned type of the same width as
+       pointers. (If you are using an ancient system that declares
+       size_t as a signed type, or need it to be a different width
+       than pointers, you can use a previous release of this malloc
+       (e.g. 2.7.2) supporting these.)
+
+  Alignment:                                     8 bytes (default)
+       This suffices for nearly all current machines and C compilers.
+       However, you can define MALLOC_ALIGNMENT to be wider than this
+       if necessary (up to 128bytes), at the expense of using more space.
+
+  Minimum overhead per allocated chunk:   4 or  8 bytes (if 4byte sizes)
+                                          8 or 16 bytes (if 8byte sizes)
+       Each malloced chunk has a hidden word of overhead holding size
+       and status information, and additional cross-check word
+       if FOOTERS is defined.
+
+  Minimum allocated size: 4-byte ptrs:  16 bytes    (including overhead)
+                          8-byte ptrs:  32 bytes    (including overhead)
+
+       Even a request for zero bytes (i.e., malloc(0)) returns a
+       pointer to something of the minimum allocatable size.
+       The maximum overhead wastage (i.e., number of extra bytes
+       allocated than were requested in malloc) is less than or equal
+       to the minimum size, except for requests >= mmap_threshold that
+       are serviced via mmap(), where the worst case wastage is about
+       32 bytes plus the remainder from a system page (the minimal
+       mmap unit); typically 4096 or 8192 bytes.
+
+  Security: static-safe; optionally more or less
+       The "security" of malloc refers to the ability of malicious
+       code to accentuate the effects of errors (for example, freeing
+       space that is not currently malloc'ed or overwriting past the
+       ends of chunks) in code that calls malloc.  This malloc
+       guarantees not to modify any memory locations below the base of
+       heap, i.e., static variables, even in the presence of usage
+       errors.  The routines additionally detect most improper frees
+       and reallocs.  All this holds as long as the static bookkeeping
+       for malloc itself is not corrupted by some other means.  This
+       is only one aspect of security -- these checks do not, and
+       cannot, detect all possible programming errors.
+
+       If FOOTERS is defined nonzero, then each allocated chunk
+       carries an additional check word to verify that it was malloced
+       from its space.  These check words are the same within each
+       execution of a program using malloc, but differ across
+       executions, so externally crafted fake chunks cannot be
+       freed. This improves security by rejecting frees/reallocs that
+       could corrupt heap memory, in addition to the checks preventing
+       writes to statics that are always on.  This may further improve
+       security at the expense of time and space overhead.  (Note that
+       FOOTERS may also be worth using with MSPACES.)
+
+       By default detected errors cause the program to abort (calling
+       "abort()"). You can override this to instead proceed past
+       errors by defining PROCEED_ON_ERROR.  In this case, a bad free
+       has no effect, and a malloc that encounters a bad address
+       caused by user overwrites will ignore the bad address by
+       dropping pointers and indices to all known memory. This may
+       be appropriate for programs that should continue if at all
+       possible in the face of programming errors, although they may
+       run out of memory because dropped memory is never reclaimed.
+
+       If you don't like either of these options, you can define
+       CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything
+       else. And if if you are sure that your program using malloc has
+       no errors or vulnerabilities, you can define INSECURE to 1,
+       which might (or might not) provide a small performance improvement.
+
+  Thread-safety: NOT thread-safe unless USE_LOCKS defined
+       When USE_LOCKS is defined, each public call to malloc, free,
+       etc is surrounded with either a pthread mutex or a win32
+       spinlock (depending on WIN32). This is not especially fast, and
+       can be a major bottleneck.  It is designed only to provide
+       minimal protection in concurrent environments, and to provide a
+       basis for extensions.  If you are using malloc in a concurrent
+       program, consider instead using ptmalloc, which is derived from
+       a version of this malloc. (See http://www.malloc.de).
+
+  System requirements: Any combination of MORECORE and/or MMAP/MUNMAP
+       This malloc can use unix sbrk or any emulation (invoked using
+       the CALL_MORECORE macro) and/or mmap/munmap or any emulation
+       (invoked using CALL_MMAP/CALL_MUNMAP) to get and release system
+       memory.  On most unix systems, it tends to work best if both
+       MORECORE and MMAP are enabled.  On Win32, it uses emulations
+       based on VirtualAlloc. It also uses common C library functions
+       like memset.
+
+  Compliance: I believe it is compliant with the Single Unix Specification
+       (See http://www.unix.org). Also SVID/XPG, ANSI C, and probably
+       others as well.
+
+* Overview of algorithms
+
+  This is not the fastest, most space-conserving, most portable, or
+  most tunable malloc ever written. However it is among the fastest
+  while also being among the most space-conserving, portable and
+  tunable.  Consistent balance across these factors results in a good
+  general-purpose allocator for malloc-intensive programs.
+
+  In most ways, this malloc is a best-fit allocator. Generally, it
+  chooses the best-fitting existing chunk for a request, with ties
+  broken in approximately least-recently-used order. (This strategy
+  normally maintains low fragmentation.) However, for requests less
+  than 256bytes, it deviates from best-fit when there is not an
+  exactly fitting available chunk by preferring to use space adjacent
+  to that used for the previous small request, as well as by breaking
+  ties in approximately most-recently-used order. (These enhance
+  locality of series of small allocations.)  And for very large requests
+  (>= 256Kb by default), it relies on system memory mapping
+  facilities, if supported.  (This helps avoid carrying around and
+  possibly fragmenting memory used only for large chunks.)
+
+  All operations (except malloc_stats and mallinfo) have execution
+  times that are bounded by a constant factor of the number of bits in
+  a size_t, not counting any clearing in calloc or copying in realloc,
+  or actions surrounding MORECORE and MMAP that have times
+  proportional to the number of non-contiguous regions returned by
+  system allocation routines, which is often just 1.
+
+  The implementation is not very modular and seriously overuses
+  macros. Perhaps someday all C compilers will do as good a job
+  inlining modular code as can now be done by brute-force expansion,
+  but now, enough of them seem not to.
+
+  Some compilers issue a lot of warnings about code that is
+  dead/unreachable only on some platforms, and also about intentional
+  uses of negation on unsigned types. All known cases of each can be
+  ignored.
+
+  For a longer but out of date high-level description, see
+     http://gee.cs.oswego.edu/dl/html/malloc.html
+
+* MSPACES
+  If MSPACES is defined, then in addition to malloc, free, etc.,
+  this file also defines mspace_malloc, mspace_free, etc. These
+  are versions of malloc routines that take an "mspace" argument
+  obtained using create_mspace, to control all internal bookkeeping.
+  If ONLY_MSPACES is defined, only these versions are compiled.
+  So if you would like to use this allocator for only some allocations,
+  and your system malloc for others, you can compile with
+  ONLY_MSPACES and then do something like...
+    static mspace mymspace = create_mspace(0,0); // for example
+    #define mymalloc(bytes)  mspace_malloc(mymspace, bytes)
+
+  (Note: If you only need one instance of an mspace, you can instead
+  use "USE_DL_PREFIX" to relabel the global malloc.)
+
+  You can similarly create thread-local allocators by storing
+  mspaces as thread-locals. For example:
+    static __thread mspace tlms = 0;
+    void*  tlmalloc(size_t bytes) {
+      if (tlms == 0) tlms = create_mspace(0, 0);
+      return mspace_malloc(tlms, bytes);
+    }
+    void  tlfree(void* mem) { mspace_free(tlms, mem); }
+
+  Unless FOOTERS is defined, each mspace is completely independent.
+  You cannot allocate from one and free to another (although
+  conformance is only weakly checked, so usage errors are not always
+  caught). If FOOTERS is defined, then each chunk carries around a tag
+  indicating its originating mspace, and frees are directed to their
+  originating spaces.
+
+ -------------------------  Compile-time options ---------------------------
+
+Be careful in setting #define values for numerical constants of type
+size_t. On some systems, literal values are not automatically extended
+to size_t precision unless they are explicitly casted.
+
+WIN32                    default: defined if _WIN32 defined
+  Defining WIN32 sets up defaults for MS environment and compilers.
+  Otherwise defaults are for unix.
+
+MALLOC_ALIGNMENT         default: (size_t)8
+  Controls the minimum alignment for malloc'ed chunks.  It must be a
+  power of two and at least 8, even on machines for which smaller
+  alignments would suffice. It may be defined as larger than this
+  though. Note however that code and data structures are optimized for
+  the case of 8-byte alignment.
+
+MSPACES                  default: 0 (false)
+  If true, compile in support for independent allocation spaces.
+  This is only supported if HAVE_MMAP is true.
+
+ONLY_MSPACES             default: 0 (false)
+  If true, only compile in mspace versions, not regular versions.
+
+USE_LOCKS                default: 0 (false)
+  Causes each call to each public routine to be surrounded with
+  pthread or WIN32 mutex lock/unlock. (If set true, this can be
+  overridden on a per-mspace basis for mspace versions.)
+
+FOOTERS                  default: 0
+  If true, provide extra checking and dispatching by placing
+  information in the footers of allocated chunks. This adds
+  space and time overhead.
+
+INSECURE                 default: 0
+  If true, omit checks for usage errors and heap space overwrites.
+
+USE_DL_PREFIX            default: NOT defined
+  Causes compiler to prefix all public routines with the string 'dl'.
+  This can be useful when you only want to use this malloc in one part
+  of a program, using your regular system malloc elsewhere.
+
+ABORT                    default: defined as abort()
+  Defines how to abort on failed checks.  On most systems, a failed
+  check cannot die with an "assert" or even print an informative
+  message, because the underlying print routines in turn call malloc,
+  which will fail again.  Generally, the best policy is to simply call
+  abort(). It's not very useful to do more than this because many
+  errors due to overwriting will show up as address faults (null, odd
+  addresses etc) rather than malloc-triggered checks, so will also
+  abort.  Also, most compilers know that abort() does not return, so
+  can better optimize code conditionally calling it.
+
+PROCEED_ON_ERROR           default: defined as 0 (false)
+  Controls whether detected bad addresses cause them to bypassed
+  rather than aborting. If set, detected bad arguments to free and
+  realloc are ignored. And all bookkeeping information is zeroed out
+  upon a detected overwrite of freed heap space, thus losing the
+  ability to ever return it from malloc again, but enabling the
+  application to proceed. If PROCEED_ON_ERROR is defined, the
+  static variable malloc_corruption_error_count is compiled in
+  and can be examined to see if errors have occurred. This option
+  generates slower code than the default abort policy.
+
+DEBUG                    default: NOT defined
+  The DEBUG setting is mainly intended for people trying to modify
+  this code or diagnose problems when porting to new platforms.
+  However, it may also be able to better isolate user errors than just
+  using runtime checks.  The assertions in the check routines spell
+  out in more detail the assumptions and invariants underlying the
+  algorithms.  The checking is fairly extensive, and will slow down
+  execution noticeably. Calling malloc_stats or mallinfo with DEBUG
+  set will attempt to check every non-mmapped allocated and free chunk
+  in the course of computing the summaries.
+
+ABORT_ON_ASSERT_FAILURE   default: defined as 1 (true)
+  Debugging assertion failures can be nearly impossible if your
+  version of the assert macro causes malloc to be called, which will
+  lead to a cascade of further failures, blowing the runtime stack.
+  ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(),
+  which will usually make debugging easier.
+
+MALLOC_FAILURE_ACTION     default: sets errno to ENOMEM, or no-op on win32
+  The action to take before "return 0" when malloc fails to be able to
+  return memory because there is none available.
+
+HAVE_MORECORE             default: 1 (true) unless win32 or ONLY_MSPACES
+  True if this system supports sbrk or an emulation of it.
+
+MORECORE                  default: sbrk
+  The name of the sbrk-style system routine to call to obtain more
+  memory.  See below for guidance on writing custom MORECORE
+  functions. The type of the argument to sbrk/MORECORE varies across
+  systems.  It cannot be size_t, because it supports negative
+  arguments, so it is normally the signed type of the same width as
+  size_t (sometimes declared as "intptr_t").  It doesn't much matter
+  though. Internally, we only call it with arguments less than half
+  the max value of a size_t, which should work across all reasonable
+  possibilities, although sometimes generating compiler warnings.  See
+  near the end of this file for guidelines for creating a custom
+  version of MORECORE.
+
+MORECORE_CONTIGUOUS       default: 1 (true)
+  If true, take advantage of fact that consecutive calls to MORECORE
+  with positive arguments always return contiguous increasing
+  addresses.  This is true of unix sbrk. It does not hurt too much to
+  set it true anyway, since malloc copes with non-contiguities.
+  Setting it false when definitely non-contiguous saves time
+  and possibly wasted space it would take to discover this though.
+
+MORECORE_CANNOT_TRIM      default: NOT defined
+  True if MORECORE cannot release space back to the system when given
+  negative arguments. This is generally necessary only if you are
+  using a hand-crafted MORECORE function that cannot handle negative
+  arguments.
+
+HAVE_MMAP                 default: 1 (true)
+  True if this system supports mmap or an emulation of it.  If so, and
+  HAVE_MORECORE is not true, MMAP is used for all system
+  allocation. If set and HAVE_MORECORE is true as well, MMAP is
+  primarily used to directly allocate very large blocks. It is also
+  used as a backup strategy in cases where MORECORE fails to provide
+  space from system. Note: A single call to MUNMAP is assumed to be
+  able to unmap memory that may have be allocated using multiple calls
+  to MMAP, so long as they are adjacent.
+
+HAVE_MREMAP               default: 1 on linux, else 0
+  If true realloc() uses mremap() to re-allocate large blocks and
+  extend or shrink allocation spaces.
+
+MMAP_CLEARS               default: 1 on unix
+  True if mmap clears memory so calloc doesn't need to. This is true
+  for standard unix mmap using /dev/zero.
+
+USE_BUILTIN_FFS            default: 0 (i.e., not used)
+  Causes malloc to use the builtin ffs() function to compute indices.
+  Some compilers may recognize and intrinsify ffs to be faster than the
+  supplied C version. Also, the case of x86 using gcc is special-cased
+  to an asm instruction, so is already as fast as it can be, and so
+  this setting has no effect. (On most x86s, the asm version is only
+  slightly faster than the C version.)
+
+malloc_getpagesize         default: derive from system includes, or 4096.
+  The system page size. To the extent possible, this malloc manages
+  memory from the system in page-size units.  This may be (and
+  usually is) a function rather than a constant. This is ignored
+  if WIN32, where page size is determined using getSystemInfo during
+  initialization.
+
+USE_DEV_RANDOM             default: 0 (i.e., not used)
+  Causes malloc to use /dev/random to initialize secure magic seed for
+  stamping footers. Otherwise, the current time is used.
+
+NO_MALLINFO                default: 0
+  If defined, don't compile "mallinfo". This can be a simple way
+  of dealing with mismatches between system declarations and
+  those in this file.
+
+MALLINFO_FIELD_TYPE        default: size_t
+  The type of the fields in the mallinfo struct. This was originally
+  defined as "int" in SVID etc, but is more usefully defined as
+  size_t. The value is used only if  HAVE_USR_INCLUDE_MALLOC_H is not set
+
+REALLOC_ZERO_BYTES_FREES    default: not defined
+  This should be set if a call to realloc with zero bytes should
+  be the same as a call to free. Some people think it should. Otherwise,
+  since this malloc returns a unique pointer for malloc(0), so does
+  realloc(p, 0).
+
+LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H
+LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H,  LACKS_ERRNO_H
+LACKS_STDLIB_H                default: NOT defined unless on WIN32
+  Define these if your system does not have these header files.
+  You might need to manually insert some of the declarations they provide.
+
+DEFAULT_GRANULARITY        default: page size if MORECORE_CONTIGUOUS,
+                                system_info.dwAllocationGranularity in WIN32,
+                                otherwise 64K.
+      Also settable using mallopt(M_GRANULARITY, x)
+  The unit for allocating and deallocating memory from the system.  On
+  most systems with contiguous MORECORE, there is no reason to
+  make this more than a page. However, systems with MMAP tend to
+  either require or encourage larger granularities.  You can increase
+  this value to prevent system allocation functions to be called so
+  often, especially if they are slow.  The value must be at least one
+  page and must be a power of two.  Setting to 0 causes initialization
+  to either page size or win32 region size.  (Note: In previous
+  versions of malloc, the equivalent of this option was called
+  "TOP_PAD")
+
+DEFAULT_TRIM_THRESHOLD    default: 2MB
+      Also settable using mallopt(M_TRIM_THRESHOLD, x)
+  The maximum amount of unused top-most memory to keep before
+  releasing via malloc_trim in free().  Automatic trimming is mainly
+  useful in long-lived programs using contiguous MORECORE.  Because
+  trimming via sbrk can be slow on some systems, and can sometimes be
+  wasteful (in cases where programs immediately afterward allocate
+  more large chunks) the value should be high enough so that your
+  overall system performance would improve by releasing this much
+  memory.  As a rough guide, you might set to a value close to the
+  average size of a process (program) running on your system.
+  Releasing this much memory would allow such a process to run in
+  memory.  Generally, it is worth tuning trim thresholds when a
+  program undergoes phases where several large chunks are allocated
+  and released in ways that can reuse each other's storage, perhaps
+  mixed with phases where there are no such chunks at all. The trim
+  value must be greater than page size to have any useful effect.  To
+  disable trimming completely, you can set to MAX_SIZE_T. Note that the trick
+  some people use of mallocing a huge space and then freeing it at
+  program startup, in an attempt to reserve system memory, doesn't
+  have the intended effect under automatic trimming, since that memory
+  will immediately be returned to the system.
+
+DEFAULT_MMAP_THRESHOLD       default: 256K
+      Also settable using mallopt(M_MMAP_THRESHOLD, x)
+  The request size threshold for using MMAP to directly service a
+  request. Requests of at least this size that cannot be allocated
+  using already-existing space will be serviced via mmap.  (If enough
+  normal freed space already exists it is used instead.)  Using mmap
+  segregates relatively large chunks of memory so that they can be
+  individually obtained and released from the host system. A request
+  serviced through mmap is never reused by any other request (at least
+  not directly; the system may just so happen to remap successive
+  requests to the same locations).  Segregating space in this way has
+  the benefits that: Mmapped space can always be individually released
+  back to the system, which helps keep the system level memory demands
+  of a long-lived program low.  Also, mapped memory doesn't become
+  `locked' between other chunks, as can happen with normally allocated
+  chunks, which means that even trimming via malloc_trim would not
+  release them.  However, it has the disadvantage that the space
+  cannot be reclaimed, consolidated, and then used to service later
+  requests, as happens with normal chunks.  The advantages of mmap
+  nearly always outweigh disadvantages for "large" chunks, but the
+  value of "large" may vary across systems.  The default is an
+  empirically derived value that works well in most systems. You can
+  disable mmap by setting to MAX_SIZE_T.
+
+*/
+
+#ifndef WIN32
+#ifdef _WIN32
+#define WIN32 1
+#endif  /* _WIN32 */
+#endif  /* WIN32 */
+#ifdef WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#define HAVE_MMAP 1
+#define HAVE_MORECORE 0
+#define LACKS_UNISTD_H
+#define LACKS_SYS_PARAM_H
+#define LACKS_SYS_MMAN_H
+#define LACKS_STRING_H
+#define LACKS_STRINGS_H
+#define LACKS_SYS_TYPES_H
+#define LACKS_ERRNO_H
+#define MALLOC_FAILURE_ACTION
+#define MMAP_CLEARS 0 /* WINCE and some others apparently don't clear */
+#endif  /* WIN32 */
+
+#if defined(DARWIN) || defined(_DARWIN)
+/* Mac OSX docs advise not to use sbrk; it seems better to use mmap */
+#ifndef HAVE_MORECORE
+#define HAVE_MORECORE 0
+#define HAVE_MMAP 1
+#endif  /* HAVE_MORECORE */
+#endif  /* DARWIN */
+
+#ifndef LACKS_SYS_TYPES_H
+#include <sys/types.h>  /* For size_t */
+#endif  /* LACKS_SYS_TYPES_H */
+
+/* The maximum possible size_t value has all bits set */
+#define MAX_SIZE_T           (~(size_t)0)
+
+#ifndef ONLY_MSPACES
+#define ONLY_MSPACES 0
+#endif  /* ONLY_MSPACES */
+#ifndef MSPACES
+#if ONLY_MSPACES
+#define MSPACES 1
+#else   /* ONLY_MSPACES */
+#define MSPACES 0
+#endif  /* ONLY_MSPACES */
+#endif  /* MSPACES */
+#ifndef MALLOC_ALIGNMENT
+#define MALLOC_ALIGNMENT ((size_t)8U)
+#endif  /* MALLOC_ALIGNMENT */
+#ifndef FOOTERS
+#define FOOTERS 0
+#endif  /* FOOTERS */
+#ifndef USE_MAX_ALLOWED_FOOTPRINT
+#define USE_MAX_ALLOWED_FOOTPRINT 0
+#endif
+#ifndef ABORT
+#define ABORT  abort()
+#endif  /* ABORT */
+#ifndef ABORT_ON_ASSERT_FAILURE
+#define ABORT_ON_ASSERT_FAILURE 1
+#endif  /* ABORT_ON_ASSERT_FAILURE */
+#ifndef PROCEED_ON_ERROR
+#define PROCEED_ON_ERROR 0
+#endif  /* PROCEED_ON_ERROR */
+#ifndef USE_LOCKS
+#define USE_LOCKS 0
+#endif  /* USE_LOCKS */
+#ifndef INSECURE
+#define INSECURE 0
+#endif  /* INSECURE */
+#ifndef HAVE_MMAP
+#define HAVE_MMAP 1
+#endif  /* HAVE_MMAP */
+#ifndef MMAP_CLEARS
+#define MMAP_CLEARS 1
+#endif  /* MMAP_CLEARS */
+#ifndef HAVE_MREMAP
+#ifdef linux
+#define HAVE_MREMAP 1
+#else   /* linux */
+#define HAVE_MREMAP 0
+#endif  /* linux */
+#endif  /* HAVE_MREMAP */
+#ifndef MALLOC_FAILURE_ACTION
+#define MALLOC_FAILURE_ACTION  errno = ENOMEM;
+#endif  /* MALLOC_FAILURE_ACTION */
+#ifndef HAVE_MORECORE
+#if ONLY_MSPACES
+#define HAVE_MORECORE 0
+#else   /* ONLY_MSPACES */
+#define HAVE_MORECORE 1
+#endif  /* ONLY_MSPACES */
+#endif  /* HAVE_MORECORE */
+#if !HAVE_MORECORE
+#define MORECORE_CONTIGUOUS 0
+#else   /* !HAVE_MORECORE */
+#ifndef MORECORE
+#define MORECORE sbrk
+#endif  /* MORECORE */
+#ifndef MORECORE_CONTIGUOUS
+#define MORECORE_CONTIGUOUS 1
+#endif  /* MORECORE_CONTIGUOUS */
+#endif  /* HAVE_MORECORE */
+#ifndef DEFAULT_GRANULARITY
+#if MORECORE_CONTIGUOUS
+#define DEFAULT_GRANULARITY (0)  /* 0 means to compute in init_mparams */
+#else   /* MORECORE_CONTIGUOUS */
+#define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U)
+#endif  /* MORECORE_CONTIGUOUS */
+#endif  /* DEFAULT_GRANULARITY */
+#ifndef DEFAULT_TRIM_THRESHOLD
+#ifndef MORECORE_CANNOT_TRIM
+#define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U)
+#else   /* MORECORE_CANNOT_TRIM */
+#define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T
+#endif  /* MORECORE_CANNOT_TRIM */
+#endif  /* DEFAULT_TRIM_THRESHOLD */
+#ifndef DEFAULT_MMAP_THRESHOLD
+#if HAVE_MMAP
+#define DEFAULT_MMAP_THRESHOLD ((size_t)64U * (size_t)1024U)
+#else   /* HAVE_MMAP */
+#define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T
+#endif  /* HAVE_MMAP */
+#endif  /* DEFAULT_MMAP_THRESHOLD */
+#ifndef USE_BUILTIN_FFS
+#define USE_BUILTIN_FFS 0
+#endif  /* USE_BUILTIN_FFS */
+#ifndef USE_DEV_RANDOM
+#define USE_DEV_RANDOM 0
+#endif  /* USE_DEV_RANDOM */
+#ifndef NO_MALLINFO
+#define NO_MALLINFO 0
+#endif  /* NO_MALLINFO */
+#ifndef MALLINFO_FIELD_TYPE
+#define MALLINFO_FIELD_TYPE size_t
+#endif  /* MALLINFO_FIELD_TYPE */
+
+/*
+  mallopt tuning options.  SVID/XPG defines four standard parameter
+  numbers for mallopt, normally defined in malloc.h.  None of these
+  are used in this malloc, so setting them has no effect. But this
+  malloc does support the following options.
+*/
+
+#define M_TRIM_THRESHOLD     (-1)
+#define M_GRANULARITY        (-2)
+#define M_MMAP_THRESHOLD     (-3)
+
+/* ------------------------ Mallinfo declarations ------------------------ */
+
+#if !NO_MALLINFO
+/*
+  This version of malloc supports the standard SVID/XPG mallinfo
+  routine that returns a struct containing usage properties and
+  statistics. It should work on any system that has a
+  /usr/include/malloc.h defining struct mallinfo.  The main
+  declaration needed is the mallinfo struct that is returned (by-copy)
+  by mallinfo().  The malloinfo struct contains a bunch of fields that
+  are not even meaningful in this version of malloc.  These fields are
+  are instead filled by mallinfo() with other numbers that might be of
+  interest.
+
+  HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
+  /usr/include/malloc.h file that includes a declaration of struct
+  mallinfo.  If so, it is included; else a compliant version is
+  declared below.  These must be precisely the same for mallinfo() to
+  work.  The original SVID version of this struct, defined on most
+  systems with mallinfo, declares all fields as ints. But some others
+  define as unsigned long. If your system defines the fields using a
+  type of different width than listed here, you MUST #include your
+  system version and #define HAVE_USR_INCLUDE_MALLOC_H.
+*/
+
+/* #define HAVE_USR_INCLUDE_MALLOC_H */
+
+#if !ANDROID
+#ifdef HAVE_USR_INCLUDE_MALLOC_H
+#include "/usr/include/malloc.h"
+#else /* HAVE_USR_INCLUDE_MALLOC_H */
+
+struct mallinfo {
+  MALLINFO_FIELD_TYPE arena;    /* non-mmapped space allocated from system */
+  MALLINFO_FIELD_TYPE ordblks;  /* number of free chunks */
+  MALLINFO_FIELD_TYPE smblks;   /* always 0 */
+  MALLINFO_FIELD_TYPE hblks;    /* always 0 */
+  MALLINFO_FIELD_TYPE hblkhd;   /* space in mmapped regions */
+  MALLINFO_FIELD_TYPE usmblks;  /* maximum total allocated space */
+  MALLINFO_FIELD_TYPE fsmblks;  /* always 0 */
+  MALLINFO_FIELD_TYPE uordblks; /* total allocated space */
+  MALLINFO_FIELD_TYPE fordblks; /* total free space */
+  MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */
+};
+
+#endif /* HAVE_USR_INCLUDE_MALLOC_H */
+#endif /* NO_MALLINFO */
+#endif /* ANDROID */
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+#if !ONLY_MSPACES
+
+/* ------------------- Declarations of public routines ------------------- */
+
+/* Check an additional macro for the five primary functions */
+#ifndef USE_DL_PREFIX
+#define dlcalloc               calloc
+#define dlfree                 free
+#define dlmalloc               malloc
+#define dlmemalign             memalign
+#define dlrealloc              realloc
+#endif
+
+#ifndef USE_DL_PREFIX
+#define dlvalloc               valloc
+#define dlpvalloc              pvalloc
+#define dlmallinfo             mallinfo
+#define dlmallopt              mallopt
+#define dlmalloc_trim          malloc_trim
+#define dlmalloc_walk_free_pages \
+                               malloc_walk_free_pages
+#define dlmalloc_walk_heap \
+                               malloc_walk_heap
+#define dlmalloc_stats         malloc_stats
+#define dlmalloc_usable_size   malloc_usable_size
+#define dlmalloc_footprint     malloc_footprint
+#define dlmalloc_max_allowed_footprint \
+                               malloc_max_allowed_footprint
+#define dlmalloc_set_max_allowed_footprint \
+                               malloc_set_max_allowed_footprint
+#define dlmalloc_max_footprint malloc_max_footprint
+#define dlindependent_calloc   independent_calloc
+#define dlindependent_comalloc independent_comalloc
+#endif /* USE_DL_PREFIX */
+
+
+/*
+  malloc(size_t n)
+  Returns a pointer to a newly allocated chunk of at least n bytes, or
+  null if no space is available, in which case errno is set to ENOMEM
+  on ANSI C systems.
+
+  If n is zero, malloc returns a minimum-sized chunk. (The minimum
+  size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
+  systems.)  Note that size_t is an unsigned type, so calls with
+  arguments that would be negative if signed are interpreted as
+  requests for huge amounts of space, which will often fail. The
+  maximum supported value of n differs across systems, but is in all
+  cases less than the maximum representable value of a size_t.
+*/
+void* dlmalloc(size_t);
+
+/*
+  free(void* p)
+  Releases the chunk of memory pointed to by p, that had been previously
+  allocated using malloc or a related routine such as realloc.
+  It has no effect if p is null. If p was not malloced or already
+  freed, free(p) will by default cause the current program to abort.
+*/
+void  dlfree(void*);
+
+/*
+  calloc(size_t n_elements, size_t element_size);
+  Returns a pointer to n_elements * element_size bytes, with all locations
+  set to zero.
+*/
+void* dlcalloc(size_t, size_t);
+
+/*
+  realloc(void* p, size_t n)
+  Returns a pointer to a chunk of size n that contains the same data
+  as does chunk p up to the minimum of (n, p's size) bytes, or null
+  if no space is available.
+
+  The returned pointer may or may not be the same as p. The algorithm
+  prefers extending p in most cases when possible, otherwise it
+  employs the equivalent of a malloc-copy-free sequence.
+
+  If p is null, realloc is equivalent to malloc.
+
+  If space is not available, realloc returns null, errno is set (if on
+  ANSI) and p is NOT freed.
+
+  if n is for fewer bytes than already held by p, the newly unused
+  space is lopped off and freed if possible.  realloc with a size
+  argument of zero (re)allocates a minimum-sized chunk.
+
+  The old unix realloc convention of allowing the last-free'd chunk
+  to be used as an argument to realloc is not supported.
+*/
+
+void* dlrealloc(void*, size_t);
+
+/*
+  memalign(size_t alignment, size_t n);
+  Returns a pointer to a newly allocated chunk of n bytes, aligned
+  in accord with the alignment argument.
+
+  The alignment argument should be a power of two. If the argument is
+  not a power of two, the nearest greater power is used.
+  8-byte alignment is guaranteed by normal malloc calls, so don't
+  bother calling memalign with an argument of 8 or less.
+
+  Overreliance on memalign is a sure way to fragment space.
+*/
+void* dlmemalign(size_t, size_t);
+
+/*
+  valloc(size_t n);
+  Equivalent to memalign(pagesize, n), where pagesize is the page
+  size of the system. If the pagesize is unknown, 4096 is used.
+*/
+void* dlvalloc(size_t);
+
+/*
+  mallopt(int parameter_number, int parameter_value)
+  Sets tunable parameters The format is to provide a
+  (parameter-number, parameter-value) pair.  mallopt then sets the
+  corresponding parameter to the argument value if it can (i.e., so
+  long as the value is meaningful), and returns 1 if successful else
+  0.  SVID/XPG/ANSI defines four standard param numbers for mallopt,
+  normally defined in malloc.h.  None of these are use in this malloc,
+  so setting them has no effect. But this malloc also supports other
+  options in mallopt. See below for details.  Briefly, supported
+  parameters are as follows (listed defaults are for "typical"
+  configurations).
+
+  Symbol            param #  default    allowed param values
+  M_TRIM_THRESHOLD     -1   2*1024*1024   any   (MAX_SIZE_T disables)
+  M_GRANULARITY        -2     page size   any power of 2 >= page size
+  M_MMAP_THRESHOLD     -3      256*1024   any   (or 0 if no MMAP support)
+*/
+int dlmallopt(int, int);
+
+/*
+  malloc_footprint();
+  Returns the number of bytes obtained from the system.  The total
+  number of bytes allocated by malloc, realloc etc., is less than this
+  value. Unlike mallinfo, this function returns only a precomputed
+  result, so can be called frequently to monitor memory consumption.
+  Even if locks are otherwise defined, this function does not use them,
+  so results might not be up to date.
+*/
+size_t dlmalloc_footprint(void);
+
+#if USE_MAX_ALLOWED_FOOTPRINT
+/*
+  malloc_max_allowed_footprint();
+  Returns the number of bytes that the heap is allowed to obtain
+  from the system.  malloc_footprint() should always return a
+  size less than or equal to max_allowed_footprint, unless the
+  max_allowed_footprint was set to a value smaller than the
+  footprint at the time.
+*/
+size_t dlmalloc_max_allowed_footprint();
+
+/*
+  malloc_set_max_allowed_footprint();
+  Set the maximum number of bytes that the heap is allowed to
+  obtain from the system.  The size will be rounded up to a whole
+  page, and the rounded number will be returned from future calls
+  to malloc_max_allowed_footprint().  If the new max_allowed_footprint
+  is larger than the current footprint, the heap will never grow
+  larger than max_allowed_footprint.  If the new max_allowed_footprint
+  is smaller than the current footprint, the heap will not grow
+  further.
+
+  TODO: try to force the heap to give up memory in the shrink case,
+        and update this comment once that happens.
+*/
+void dlmalloc_set_max_allowed_footprint(size_t bytes);
+#endif /* USE_MAX_ALLOWED_FOOTPRINT */
+
+/*
+  malloc_max_footprint();
+  Returns the maximum number of bytes obtained from the system. This
+  value will be greater than current footprint if deallocated space
+  has been reclaimed by the system. The peak number of bytes allocated
+  by malloc, realloc etc., is less than this value. Unlike mallinfo,
+  this function returns only a precomputed result, so can be called
+  frequently to monitor memory consumption.  Even if locks are
+  otherwise defined, this function does not use them, so results might
+  not be up to date.
+*/
+size_t dlmalloc_max_footprint(void);
+
+#if !NO_MALLINFO
+/*
+  mallinfo()
+  Returns (by copy) a struct containing various summary statistics:
+
+  arena:     current total non-mmapped bytes allocated from system
+  ordblks:   the number of free chunks
+  smblks:    always zero.
+  hblks:     current number of mmapped regions
+  hblkhd:    total bytes held in mmapped regions
+  usmblks:   the maximum total allocated space. This will be greater
+                than current total if trimming has occurred.
+  fsmblks:   always zero
+  uordblks:  current total allocated space (normal or mmapped)
+  fordblks:  total free space
+  keepcost:  the maximum number of bytes that could ideally be released
+               back to system via malloc_trim. ("ideally" means that
+               it ignores page restrictions etc.)
+
+  Because these fields are ints, but internal bookkeeping may
+  be kept as longs, the reported values may wrap around zero and
+  thus be inaccurate.
+*/
+struct mallinfo dlmallinfo(void);
+#endif /* NO_MALLINFO */
+
+/*
+  independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
+
+  independent_calloc is similar to calloc, but instead of returning a
+  single cleared space, it returns an array of pointers to n_elements
+  independent elements that can hold contents of size elem_size, each
+  of which starts out cleared, and can be independently freed,
+  realloc'ed etc. The elements are guaranteed to be adjacently
+  allocated (this is not guaranteed to occur with multiple callocs or
+  mallocs), which may also improve cache locality in some
+  applications.
+
+  The "chunks" argument is optional (i.e., may be null, which is
+  probably the most typical usage). If it is null, the returned array
+  is itself dynamically allocated and should also be freed when it is
+  no longer needed. Otherwise, the chunks array must be of at least
+  n_elements in length. It is filled in with the pointers to the
+  chunks.
+
+  In either case, independent_calloc returns this pointer array, or
+  null if the allocation failed.  If n_elements is zero and "chunks"
+  is null, it returns a chunk representing an array with zero elements
+  (which should be freed if not wanted).
+
+  Each element must be individually freed when it is no longer
+  needed. If you'd like to instead be able to free all at once, you
+  should instead use regular calloc and assign pointers into this
+  space to represent elements.  (In this case though, you cannot
+  independently free elements.)
+
+  independent_calloc simplifies and speeds up implementations of many
+  kinds of pools.  It may also be useful when constructing large data
+  structures that initially have a fixed number of fixed-sized nodes,
+  but the number is not known at compile time, and some of the nodes
+  may later need to be freed. For example:
+
+  struct Node { int item; struct Node* next; };
+
+  struct Node* build_list() {
+    struct Node** pool;
+    int n = read_number_of_nodes_needed();
+    if (n <= 0) return 0;
+    pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
+    if (pool == 0) die();
+    // organize into a linked list...
+    struct Node* first = pool[0];
+    for (i = 0; i < n-1; ++i)
+      pool[i]->next = pool[i+1];
+    free(pool);     // Can now free the array (or not, if it is needed later)
+    return first;
+  }
+*/
+void** dlindependent_calloc(size_t, size_t, void**);
+
+/*
+  independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
+
+  independent_comalloc allocates, all at once, a set of n_elements
+  chunks with sizes indicated in the "sizes" array.    It returns
+  an array of pointers to these elements, each of which can be
+  independently freed, realloc'ed etc. The elements are guaranteed to
+  be adjacently allocated (this is not guaranteed to occur with
+  multiple callocs or mallocs), which may also improve cache locality
+  in some applications.
+
+  The "chunks" argument is optional (i.e., may be null). If it is null
+  the returned array is itself dynamically allocated and should also
+  be freed when it is no longer needed. Otherwise, the chunks array
+  must be of at least n_elements in length. It is filled in with the
+  pointers to the chunks.
+
+  In either case, independent_comalloc returns this pointer array, or
+  null if the allocation failed.  If n_elements is zero and chunks is
+  null, it returns a chunk representing an array with zero elements
+  (which should be freed if not wanted).
+
+  Each element must be individually freed when it is no longer
+  needed. If you'd like to instead be able to free all at once, you
+  should instead use a single regular malloc, and assign pointers at
+  particular offsets in the aggregate space. (In this case though, you
+  cannot independently free elements.)
+
+  independent_comallac differs from independent_calloc in that each
+  element may have a different size, and also that it does not
+  automatically clear elements.
+
+  independent_comalloc can be used to speed up allocation in cases
+  where several structs or objects must always be allocated at the
+  same time.  For example:
+
+  struct Head { ... }
+  struct Foot { ... }
+
+  void send_message(char* msg) {
+    int msglen = strlen(msg);
+    size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
+    void* chunks[3];
+    if (independent_comalloc(3, sizes, chunks) == 0)
+      die();
+    struct Head* head = (struct Head*)(chunks[0]);
+    char*        body = (char*)(chunks[1]);
+    struct Foot* foot = (struct Foot*)(chunks[2]);
+    // ...
+  }
+
+  In general though, independent_comalloc is worth using only for
+  larger values of n_elements. For small values, you probably won't
+  detect enough difference from series of malloc calls to bother.
+
+  Overuse of independent_comalloc can increase overall memory usage,
+  since it cannot reuse existing noncontiguous small chunks that
+  might be available for some of the elements.
+*/
+void** dlindependent_comalloc(size_t, size_t*, void**);
+
+
+/*
+  pvalloc(size_t n);
+  Equivalent to valloc(minimum-page-that-holds(n)), that is,
+  round up n to nearest pagesize.
+ */
+void*  dlpvalloc(size_t);
+
+/*
+  malloc_trim(size_t pad);
+
+  If possible, gives memory back to the system (via negative arguments
+  to sbrk) if there is unused memory at the `high' end of the malloc
+  pool or in unused MMAP segments. You can call this after freeing
+  large blocks of memory to potentially reduce the system-level memory
+  requirements of a program. However, it cannot guarantee to reduce
+  memory. Under some allocation patterns, some large free blocks of
+  memory will be locked between two used chunks, so they cannot be
+  given back to the system.
+
+  The `pad' argument to malloc_trim represents the amount of free
+  trailing space to leave untrimmed. If this argument is zero, only
+  the minimum amount of memory to maintain internal data structures
+  will be left. Non-zero arguments can be supplied to maintain enough
+  trailing space to service future expected allocations without having
+  to re-obtain memory from the system.
+
+  Malloc_trim returns 1 if it actually released any memory, else 0.
+*/
+int  dlmalloc_trim(size_t);
+
+/*
+  malloc_walk_free_pages(handler, harg)
+
+  Calls the provided handler on each free region in the heap.  The
+  memory between start and end are guaranteed not to contain any
+  important data, so the handler is free to alter the contents
+  in any way.  This can be used to advise the OS that large free
+  regions may be swapped out.
+
+  The value in harg will be passed to each call of the handler.
+ */
+void dlmalloc_walk_free_pages(void(*)(void*, void*, void*), void*);
+
+/*
+  malloc_walk_heap(handler, harg)
+
+  Calls the provided handler on each object or free region in the
+  heap.  The handler will receive the chunk pointer and length, the
+  object pointer and length, and the value in harg on each call.
+ */
+void dlmalloc_walk_heap(void(*)(const void*, size_t,
+                                const void*, size_t, void*),
+                        void*);
+
+/*
+  malloc_usable_size(void* p);
+
+  Returns the number of bytes you can actually use in
+  an allocated chunk, which may be more than you requested (although
+  often not) due to alignment and minimum size constraints.
+  You can use this many bytes without worrying about
+  overwriting other allocated objects. This is not a particularly great
+  programming practice. malloc_usable_size can be more useful in
+  debugging and assertions, for example:
+
+  p = malloc(n);
+  assert(malloc_usable_size(p) >= 256);
+*/
+size_t dlmalloc_usable_size(void*);
+
+/*
+  malloc_stats();
+  Prints on stderr the amount of space obtained from the system (both
+  via sbrk and mmap), the maximum amount (which may be more than
+  current if malloc_trim and/or munmap got called), and the current
+  number of bytes allocated via malloc (or realloc, etc) but not yet
+  freed. Note that this is the number of bytes allocated, not the
+  number requested. It will be larger than the number requested
+  because of alignment and bookkeeping overhead. Because it includes
+  alignment wastage as being in use, this figure may be greater than
+  zero even when no user-level chunks are allocated.
+
+  The reported current and maximum system memory can be inaccurate if
+  a program makes other calls to system memory allocation functions
+  (normally sbrk) outside of malloc.
+
+  malloc_stats prints only the most commonly interesting statistics.
+  More information can be obtained by calling mallinfo.
+*/
+void  dlmalloc_stats(void);
+
+#endif /* ONLY_MSPACES */
+
+#if MSPACES
+
+/*
+  mspace is an opaque type representing an independent
+  region of space that supports mspace_malloc, etc.
+*/
+typedef void* mspace;
+
+/*
+  create_mspace creates and returns a new independent space with the
+  given initial capacity, or, if 0, the default granularity size.  It
+  returns null if there is no system memory available to create the
+  space.  If argument locked is non-zero, the space uses a separate
+  lock to control access. The capacity of the space will grow
+  dynamically as needed to service mspace_malloc requests.  You can
+  control the sizes of incremental increases of this space by
+  compiling with a different DEFAULT_GRANULARITY or dynamically
+  setting with mallopt(M_GRANULARITY, value).
+*/
+mspace create_mspace(size_t capacity, int locked);
+
+/*
+  destroy_mspace destroys the given space, and attempts to return all
+  of its memory back to the system, returning the total number of
+  bytes freed. After destruction, the results of access to all memory
+  used by the space become undefined.
+*/
+size_t destroy_mspace(mspace msp);
+
+/*
+  create_mspace_with_base uses the memory supplied as the initial base
+  of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
+  space is used for bookkeeping, so the capacity must be at least this
+  large. (Otherwise 0 is returned.) When this initial space is
+  exhausted, additional memory will be obtained from the system.
+  Destroying this space will deallocate all additionally allocated
+  space (if possible) but not the initial base.
+*/
+mspace create_mspace_with_base(void* base, size_t capacity, int locked);
+
+/*
+  mspace_malloc behaves as malloc, but operates within
+  the given space.
+*/
+void* mspace_malloc(mspace msp, size_t bytes);
+
+/*
+  mspace_free behaves as free, but operates within
+  the given space.
+
+  If compiled with FOOTERS==1, mspace_free is not actually needed.
+  free may be called instead of mspace_free because freed chunks from
+  any space are handled by their originating spaces.
+*/
+void mspace_free(mspace msp, void* mem);
+
+/*
+  mspace_realloc behaves as realloc, but operates within
+  the given space.
+
+  If compiled with FOOTERS==1, mspace_realloc is not actually
+  needed.  realloc may be called instead of mspace_realloc because
+  realloced chunks from any space are handled by their originating
+  spaces.
+*/
+void* mspace_realloc(mspace msp, void* mem, size_t newsize);
+
+#if ANDROID /* Added for Android, not part of dlmalloc as released */
+/*
+  mspace_merge_objects will merge allocated memory mema and memb
+  together, provided memb immediately follows mema.  It is roughly as
+  if memb has been freed and mema has been realloced to a larger size.
+  On successfully merging, mema will be returned. If either argument
+  is null or memb does not immediately follow mema, null will be
+  returned.
+
+  Both mema and memb should have been previously allocated using
+  malloc or a related routine such as realloc. If either mema or memb
+  was not malloced or was previously freed, the result is undefined,
+  but like mspace_free, the default is to abort the program.
+*/
+void* mspace_merge_objects(mspace msp, void* mema, void* memb);
+#endif
+
+/*
+  mspace_calloc behaves as calloc, but operates within
+  the given space.
+*/
+void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
+
+/*
+  mspace_memalign behaves as memalign, but operates within
+  the given space.
+*/
+void* mspace_memalign(mspace msp, size_t alignment, size_t bytes);
+
+/*
+  mspace_independent_calloc behaves as independent_calloc, but
+  operates within the given space.
+*/
+void** mspace_independent_calloc(mspace msp, size_t n_elements,
+                                 size_t elem_size, void* chunks[]);
+
+/*
+  mspace_independent_comalloc behaves as independent_comalloc, but
+  operates within the given space.
+*/
+void** mspace_independent_comalloc(mspace msp, size_t n_elements,
+                                   size_t sizes[], void* chunks[]);
+
+/*
+  mspace_footprint() returns the number of bytes obtained from the
+  system for this space.
+*/
+size_t mspace_footprint(mspace msp);
+
+/*
+  mspace_max_footprint() returns the peak number of bytes obtained from the
+  system for this space.
+*/
+size_t mspace_max_footprint(mspace msp);
+
+
+#if !NO_MALLINFO
+/*
+  mspace_mallinfo behaves as mallinfo, but reports properties of
+  the given space.
+*/
+struct mallinfo mspace_mallinfo(mspace msp);
+#endif /* NO_MALLINFO */
+
+/*
+  mspace_malloc_stats behaves as malloc_stats, but reports
+  properties of the given space.
+*/
+void mspace_malloc_stats(mspace msp);
+
+/*
+  mspace_trim behaves as malloc_trim, but
+  operates within the given space.
+*/
+int mspace_trim(mspace msp, size_t pad);
+
+/*
+  An alias for mallopt.
+*/
+int mspace_mallopt(int, int);
+
+#endif /* MSPACES */
+
+#ifdef __cplusplus
+};  /* end of extern "C" */
+#endif /* __cplusplus */
+
+/*
+  ========================================================================
+  To make a fully customizable malloc.h header file, cut everything
+  above this line, put into file malloc.h, edit to suit, and #include it
+  on the next line, as well as in programs that use this malloc.
+  ========================================================================
+*/
+
+/* #include "malloc.h" */
+
+/*------------------------------ internal #includes ---------------------- */
+
+#ifdef WIN32
+#pragma warning( disable : 4146 ) /* no "unsigned" warnings */
+#endif /* WIN32 */
+
+#include <stdio.h>       /* for printing in malloc_stats */
+
+#ifndef LACKS_ERRNO_H
+#include <errno.h>       /* for MALLOC_FAILURE_ACTION */
+#endif /* LACKS_ERRNO_H */
+#if FOOTERS
+#include <time.h>        /* for magic initialization */
+#endif /* FOOTERS */
+#ifndef LACKS_STDLIB_H
+#include <stdlib.h>      /* for abort() */
+#endif /* LACKS_STDLIB_H */
+#ifdef DEBUG
+#if ABORT_ON_ASSERT_FAILURE
+#define assert(x) if(!(x)) ABORT
+#else /* ABORT_ON_ASSERT_FAILURE */
+#include <assert.h>
+#endif /* ABORT_ON_ASSERT_FAILURE */
+#else  /* DEBUG */
+#define assert(x)
+#endif /* DEBUG */
+#ifndef LACKS_STRING_H
+#include <string.h>      /* for memset etc */
+#endif  /* LACKS_STRING_H */
+#if USE_BUILTIN_FFS
+#ifndef LACKS_STRINGS_H
+#include <strings.h>     /* for ffs */
+#endif /* LACKS_STRINGS_H */
+#endif /* USE_BUILTIN_FFS */
+#if HAVE_MMAP
+#ifndef LACKS_SYS_MMAN_H
+#include <sys/mman.h>    /* for mmap */
+#endif /* LACKS_SYS_MMAN_H */
+#ifndef LACKS_FCNTL_H
+#include <fcntl.h>
+#endif /* LACKS_FCNTL_H */
+#endif /* HAVE_MMAP */
+#if HAVE_MORECORE
+#ifndef LACKS_UNISTD_H
+#include <unistd.h>     /* for sbrk */
+#else /* LACKS_UNISTD_H */
+#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
+extern void*     sbrk(ptrdiff_t);
+#endif /* FreeBSD etc */
+#endif /* LACKS_UNISTD_H */
+#endif /* HAVE_MMAP */
+
+#ifndef WIN32
+#ifndef malloc_getpagesize
+#  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
+#    ifndef _SC_PAGE_SIZE
+#      define _SC_PAGE_SIZE _SC_PAGESIZE
+#    endif
+#  endif
+#  ifdef _SC_PAGE_SIZE
+#    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
+#  else
+#    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
+       extern size_t getpagesize();
+#      define malloc_getpagesize getpagesize()
+#    else
+#      ifdef WIN32 /* use supplied emulation of getpagesize */
+#        define malloc_getpagesize getpagesize()
+#      else
+#        ifndef LACKS_SYS_PARAM_H
+#          include <sys/param.h>
+#        endif
+#        ifdef EXEC_PAGESIZE
+#          define malloc_getpagesize EXEC_PAGESIZE
+#        else
+#          ifdef NBPG
+#            ifndef CLSIZE
+#              define malloc_getpagesize NBPG
+#            else
+#              define malloc_getpagesize (NBPG * CLSIZE)
+#            endif
+#          else
+#            ifdef NBPC
+#              define malloc_getpagesize NBPC
+#            else
+#              ifdef PAGESIZE
+#                define malloc_getpagesize PAGESIZE
+#              else /* just guess */
+#                define malloc_getpagesize ((size_t)4096U)
+#              endif
+#            endif
+#          endif
+#        endif
+#      endif
+#    endif
+#  endif
+#endif
+#endif
+
+/* ------------------- size_t and alignment properties -------------------- */
+
+/* The byte and bit size of a size_t */
+#define SIZE_T_SIZE         (sizeof(size_t))
+#define SIZE_T_BITSIZE      (sizeof(size_t) << 3)
+
+/* Some constants coerced to size_t */
+/* Annoying but necessary to avoid errors on some plaftorms */
+#define SIZE_T_ZERO         ((size_t)0)
+#define SIZE_T_ONE          ((size_t)1)
+#define SIZE_T_TWO          ((size_t)2)
+#define TWO_SIZE_T_SIZES    (SIZE_T_SIZE<<1)
+#define FOUR_SIZE_T_SIZES   (SIZE_T_SIZE<<2)
+#define SIX_SIZE_T_SIZES    (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES)
+#define HALF_MAX_SIZE_T     (MAX_SIZE_T / 2U)
+
+/* The bit mask value corresponding to MALLOC_ALIGNMENT */
+#define CHUNK_ALIGN_MASK    (MALLOC_ALIGNMENT - SIZE_T_ONE)
+
+/* True if address a has acceptable alignment */
+#define is_aligned(A)       (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0)
+
+/* the number of bytes to offset an address to align it */
+#define align_offset(A)\
+ ((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\
+  ((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK))
+
+/* -------------------------- MMAP preliminaries ------------------------- */
+
+/*
+   If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and
+   checks to fail so compiler optimizer can delete code rather than
+   using so many "#if"s.
+*/
+
+
+/* MORECORE and MMAP must return MFAIL on failure */
+#define MFAIL                ((void*)(MAX_SIZE_T))
+#define CMFAIL               ((char*)(MFAIL)) /* defined for convenience */
+
+#if !HAVE_MMAP
+#define IS_MMAPPED_BIT       (SIZE_T_ZERO)
+#define USE_MMAP_BIT         (SIZE_T_ZERO)
+#define CALL_MMAP(s)         MFAIL
+#define CALL_MUNMAP(a, s)    (-1)
+#define DIRECT_MMAP(s)       MFAIL
+
+#else /* HAVE_MMAP */
+#define IS_MMAPPED_BIT       (SIZE_T_ONE)
+#define USE_MMAP_BIT         (SIZE_T_ONE)
+
+#ifndef WIN32
+#define CALL_MUNMAP(a, s)    munmap((a), (s))
+#define MMAP_PROT            (PROT_READ|PROT_WRITE)
+#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
+#define MAP_ANONYMOUS        MAP_ANON
+#endif /* MAP_ANON */
+#ifdef MAP_ANONYMOUS
+#define MMAP_FLAGS           (MAP_PRIVATE|MAP_ANONYMOUS)
+#define CALL_MMAP(s)         mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
+#else /* MAP_ANONYMOUS */
+/*
+   Nearly all versions of mmap support MAP_ANONYMOUS, so the following
+   is unlikely to be needed, but is supplied just in case.
+*/
+#define MMAP_FLAGS           (MAP_PRIVATE)
+static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */
+#define CALL_MMAP(s) ((dev_zero_fd < 0) ? \
+           (dev_zero_fd = open("/dev/zero", O_RDWR), \
+            mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) : \
+            mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0))
+#endif /* MAP_ANONYMOUS */
+
+#define DIRECT_MMAP(s)       CALL_MMAP(s)
+#else /* WIN32 */
+
+/* Win32 MMAP via VirtualAlloc */
+static void* win32mmap(size_t size) {
+  void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE);
+  return (ptr != 0)? ptr: MFAIL;
+}
+
+/* For direct MMAP, use MEM_TOP_DOWN to minimize interference */
+static void* win32direct_mmap(size_t size) {
+  void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT|MEM_TOP_DOWN,
+                           PAGE_READWRITE);
+  return (ptr != 0)? ptr: MFAIL;
+}
+
+/* This function supports releasing coalesed segments */
+static int win32munmap(void* ptr, size_t size) {
+  MEMORY_BASIC_INFORMATION minfo;
+  char* cptr = ptr;
+  while (size) {
+    if (VirtualQuery(cptr, &minfo, sizeof(minfo)) == 0)
+      return -1;
+    if (minfo.BaseAddress != cptr || minfo.AllocationBase != cptr ||
+        minfo.State != MEM_COMMIT || minfo.RegionSize > size)
+      return -1;
+    if (VirtualFree(cptr, 0, MEM_RELEASE) == 0)
+      return -1;
+    cptr += minfo.RegionSize;
+    size -= minfo.RegionSize;
+  }
+  return 0;
+}
+
+#define CALL_MMAP(s)         win32mmap(s)
+#define CALL_MUNMAP(a, s)    win32munmap((a), (s))
+#define DIRECT_MMAP(s)       win32direct_mmap(s)
+#endif /* WIN32 */
+#endif /* HAVE_MMAP */
+
+#if HAVE_MMAP && HAVE_MREMAP
+#define CALL_MREMAP(addr, osz, nsz, mv) mremap((addr), (osz), (nsz), (mv))
+#else  /* HAVE_MMAP && HAVE_MREMAP */
+#define CALL_MREMAP(addr, osz, nsz, mv) MFAIL
+#endif /* HAVE_MMAP && HAVE_MREMAP */
+
+#if HAVE_MORECORE
+#define CALL_MORECORE(S)     MORECORE(S)
+#else  /* HAVE_MORECORE */
+#define CALL_MORECORE(S)     MFAIL
+#endif /* HAVE_MORECORE */
+
+/* mstate bit set if continguous morecore disabled or failed */
+#define USE_NONCONTIGUOUS_BIT (4U)
+
+/* segment bit set in create_mspace_with_base */
+#define EXTERN_BIT            (8U)
+
+
+/* --------------------------- Lock preliminaries ------------------------ */
+
+#if USE_LOCKS
+
+/*
+  When locks are defined, there are up to two global locks:
+
+  * If HAVE_MORECORE, morecore_mutex protects sequences of calls to
+    MORECORE.  In many cases sys_alloc requires two calls, that should
+    not be interleaved with calls by other threads.  This does not
+    protect against direct calls to MORECORE by other threads not
+    using this lock, so there is still code to cope the best we can on
+    interference.
+
+  * magic_init_mutex ensures that mparams.magic and other
+    unique mparams values are initialized only once.
+*/
+
+#ifndef WIN32
+/* By default use posix locks */
+#include <pthread.h>
+#define MLOCK_T pthread_mutex_t
+#define INITIAL_LOCK(l)      pthread_mutex_init(l, NULL)
+#define ACQUIRE_LOCK(l)      pthread_mutex_lock(l)
+#define RELEASE_LOCK(l)      pthread_mutex_unlock(l)
+
+#if HAVE_MORECORE
+static MLOCK_T morecore_mutex = PTHREAD_MUTEX_INITIALIZER;
+#endif /* HAVE_MORECORE */
+
+static MLOCK_T magic_init_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+#else /* WIN32 */
+/*
+   Because lock-protected regions have bounded times, and there
+   are no recursive lock calls, we can use simple spinlocks.
+*/
+
+#define MLOCK_T long
+static int win32_acquire_lock (MLOCK_T *sl) {
+  for (;;) {
+#ifdef InterlockedCompareExchangePointer
+    if (!InterlockedCompareExchange(sl, 1, 0))
+      return 0;
+#else  /* Use older void* version */
+    if (!InterlockedCompareExchange((void**)sl, (void*)1, (void*)0))
+      return 0;
+#endif /* InterlockedCompareExchangePointer */
+    Sleep (0);
+  }
+}
+
+static void win32_release_lock (MLOCK_T *sl) {
+  InterlockedExchange (sl, 0);
+}
+
+#define INITIAL_LOCK(l)      *(l)=0
+#define ACQUIRE_LOCK(l)      win32_acquire_lock(l)
+#define RELEASE_LOCK(l)      win32_release_lock(l)
+#if HAVE_MORECORE
+static MLOCK_T morecore_mutex;
+#endif /* HAVE_MORECORE */
+static MLOCK_T magic_init_mutex;
+#endif /* WIN32 */
+
+#define USE_LOCK_BIT               (2U)
+#else  /* USE_LOCKS */
+#define USE_LOCK_BIT               (0U)
+#define INITIAL_LOCK(l)
+#endif /* USE_LOCKS */
+
+#if USE_LOCKS && HAVE_MORECORE
+#define ACQUIRE_MORECORE_LOCK()    ACQUIRE_LOCK(&morecore_mutex);
+#define RELEASE_MORECORE_LOCK()    RELEASE_LOCK(&morecore_mutex);
+#else /* USE_LOCKS && HAVE_MORECORE */
+#define ACQUIRE_MORECORE_LOCK()
+#define RELEASE_MORECORE_LOCK()
+#endif /* USE_LOCKS && HAVE_MORECORE */
+
+#if USE_LOCKS
+#define ACQUIRE_MAGIC_INIT_LOCK()  ACQUIRE_LOCK(&magic_init_mutex);
+#define RELEASE_MAGIC_INIT_LOCK()  RELEASE_LOCK(&magic_init_mutex);
+#else  /* USE_LOCKS */
+#define ACQUIRE_MAGIC_INIT_LOCK()
+#define RELEASE_MAGIC_INIT_LOCK()
+#endif /* USE_LOCKS */
+
+
+/* -----------------------  Chunk representations ------------------------ */
+
+/*
+  (The following includes lightly edited explanations by Colin Plumb.)
+
+  The malloc_chunk declaration below is misleading (but accurate and
+  necessary).  It declares a "view" into memory allowing access to
+  necessary fields at known offsets from a given base.
+
+  Chunks of memory are maintained using a `boundary tag' method as
+  originally described by Knuth.  (See the paper by Paul Wilson
+  ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such
+  techniques.)  Sizes of free chunks are stored both in the front of
+  each chunk and at the end.  This makes consolidating fragmented
+  chunks into bigger chunks fast.  The head fields also hold bits
+  representing whether chunks are free or in use.
+
+  Here are some pictures to make it clearer.  They are "exploded" to
+  show that the state of a chunk can be thought of as extending from
+  the high 31 bits of the head field of its header through the
+  prev_foot and PINUSE_BIT bit of the following chunk header.
+
+  A chunk that's in use looks like:
+
+   chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+           | Size of previous chunk (if P = 1)                             |
+           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
+         | Size of this chunk                                         1| +-+
+   mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         |                                                               |
+         +-                                                             -+
+         |                                                               |
+         +-                                                             -+
+         |                                                               :
+         +-      size - sizeof(size_t) available payload bytes          -+
+         :                                                               |
+ chunk-> +-                                                             -+
+         |                                                               |
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|
+       | Size of next chunk (may or may not be in use)               | +-+
+ mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+    And if it's free, it looks like this:
+
+   chunk-> +-                                                             -+
+           | User payload (must be in use, or we would have merged!)       |
+           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
+         | Size of this chunk                                         0| +-+
+   mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         | Next pointer                                                  |
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         | Prev pointer                                                  |
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         |                                                               :
+         +-      size - sizeof(struct chunk) unused bytes               -+
+         :                                                               |
+ chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         | Size of this chunk                                            |
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|
+       | Size of next chunk (must be in use, or we would have merged)| +-+
+ mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+       |                                                               :
+       +- User payload                                                -+
+       :                                                               |
+       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+                                                                     |0|
+                                                                     +-+
+  Note that since we always merge adjacent free chunks, the chunks
+  adjacent to a free chunk must be in use.
+
+  Given a pointer to a chunk (which can be derived trivially from the
+  payload pointer) we can, in O(1) time, find out whether the adjacent
+  chunks are free, and if so, unlink them from the lists that they
+  are on and merge them with the current chunk.
+
+  Chunks always begin on even word boundaries, so the mem portion
+  (which is returned to the user) is also on an even word boundary, and
+  thus at least double-word aligned.
+
+  The P (PINUSE_BIT) bit, stored in the unused low-order bit of the
+  chunk size (which is always a multiple of two words), is an in-use
+  bit for the *previous* chunk.  If that bit is *clear*, then the
+  word before the current chunk size contains the previous chunk
+  size, and can be used to find the front of the previous chunk.
+  The very first chunk allocated always has this bit set, preventing
+  access to non-existent (or non-owned) memory. If pinuse is set for
+  any given chunk, then you CANNOT determine the size of the
+  previous chunk, and might even get a memory addressing fault when
+  trying to do so.
+
+  The C (CINUSE_BIT) bit, stored in the unused second-lowest bit of
+  the chunk size redundantly records whether the current chunk is
+  inuse. This redundancy enables usage checks within free and realloc,
+  and reduces indirection when freeing and consolidating chunks.
+
+  Each freshly allocated chunk must have both cinuse and pinuse set.
+  That is, each allocated chunk borders either a previously allocated
+  and still in-use chunk, or the base of its memory arena. This is
+  ensured by making all allocations from the the `lowest' part of any
+  found chunk.  Further, no free chunk physically borders another one,
+  so each free chunk is known to be preceded and followed by either
+  inuse chunks or the ends of memory.
+
+  Note that the `foot' of the current chunk is actually represented
+  as the prev_foot of the NEXT chunk. This makes it easier to
+  deal with alignments etc but can be very confusing when trying
+  to extend or adapt this code.
+
+  The exceptions to all this are
+
+     1. The special chunk `top' is the top-most available chunk (i.e.,
+        the one bordering the end of available memory). It is treated
+        specially.  Top is never included in any bin, is used only if
+        no other chunk is available, and is released back to the
+        system if it is very large (see M_TRIM_THRESHOLD).  In effect,
+        the top chunk is treated as larger (and thus less well
+        fitting) than any other available chunk.  The top chunk
+        doesn't update its trailing size field since there is no next
+        contiguous chunk that would have to index off it. However,
+        space is still allocated for it (TOP_FOOT_SIZE) to enable
+        separation or merging when space is extended.
+
+     3. Chunks allocated via mmap, which have the lowest-order bit
+        (IS_MMAPPED_BIT) set in their prev_foot fields, and do not set
+        PINUSE_BIT in their head fields.  Because they are allocated
+        one-by-one, each must carry its own prev_foot field, which is
+        also used to hold the offset this chunk has within its mmapped
+        region, which is needed to preserve alignment. Each mmapped
+        chunk is trailed by the first two fields of a fake next-chunk
+        for sake of usage checks.
+
+*/
+
+struct malloc_chunk {
+  size_t               prev_foot;  /* Size of previous chunk (if free).  */
+  size_t               head;       /* Size and inuse bits. */
+  struct malloc_chunk* fd;         /* double links -- used only if free. */
+  struct malloc_chunk* bk;
+};
+
+typedef struct malloc_chunk  mchunk;
+typedef struct malloc_chunk* mchunkptr;
+typedef struct malloc_chunk* sbinptr;  /* The type of bins of chunks */
+typedef unsigned int bindex_t;         /* Described below */
+typedef unsigned int binmap_t;         /* Described below */
+typedef unsigned int flag_t;           /* The type of various bit flag sets */
+
+/* ------------------- Chunks sizes and alignments ----------------------- */
+
+#define MCHUNK_SIZE         (sizeof(mchunk))
+
+#if FOOTERS
+#define CHUNK_OVERHEAD      (TWO_SIZE_T_SIZES)
+#else /* FOOTERS */
+#define CHUNK_OVERHEAD      (SIZE_T_SIZE)
+#endif /* FOOTERS */
+
+/* MMapped chunks need a second word of overhead ... */
+#define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
+/* ... and additional padding for fake next-chunk at foot */
+#define MMAP_FOOT_PAD       (FOUR_SIZE_T_SIZES)
+
+/* The smallest size we can malloc is an aligned minimal chunk */
+#define MIN_CHUNK_SIZE\
+  ((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
+
+/* conversion from malloc headers to user pointers, and back */
+#define chunk2mem(p)        ((void*)((char*)(p)       + TWO_SIZE_T_SIZES))
+#define mem2chunk(mem)      ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES))
+/* chunk associated with aligned address A */
+#define align_as_chunk(A)   (mchunkptr)((A) + align_offset(chunk2mem(A)))
+
+/* Bounds on request (not chunk) sizes. */
+#define MAX_REQUEST         ((-MIN_CHUNK_SIZE) << 2)
+#define MIN_REQUEST         (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE)
+
+/* pad request bytes into a usable size */
+#define pad_request(req) \
+   (((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
+
+/* pad request, checking for minimum (but not maximum) */
+#define request2size(req) \
+  (((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req))
+
+
+/* ------------------ Operations on head and foot fields ----------------- */
+
+/*
+  The head field of a chunk is or'ed with PINUSE_BIT when previous
+  adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in
+  use. If the chunk was obtained with mmap, the prev_foot field has
+  IS_MMAPPED_BIT set, otherwise holding the offset of the base of the
+  mmapped region to the base of the chunk.
+*/
+
+#define PINUSE_BIT          (SIZE_T_ONE)
+#define CINUSE_BIT          (SIZE_T_TWO)
+#define INUSE_BITS          (PINUSE_BIT|CINUSE_BIT)
+
+/* Head value for fenceposts */
+#define FENCEPOST_HEAD      (INUSE_BITS|SIZE_T_SIZE)
+
+/* extraction of fields from head words */
+#define cinuse(p)           ((p)->head & CINUSE_BIT)
+#define pinuse(p)           ((p)->head & PINUSE_BIT)
+#define chunksize(p)        ((p)->head & ~(INUSE_BITS))
+
+#define clear_pinuse(p)     ((p)->head &= ~PINUSE_BIT)
+#define clear_cinuse(p)     ((p)->head &= ~CINUSE_BIT)
+
+/* Treat space at ptr +/- offset as a chunk */
+#define chunk_plus_offset(p, s)  ((mchunkptr)(((char*)(p)) + (s)))
+#define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s)))
+
+/* Ptr to next or previous physical malloc_chunk. */
+#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~INUSE_BITS)))
+#define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) ))
+
+/* extract next chunk's pinuse bit */
+#define next_pinuse(p)  ((next_chunk(p)->head) & PINUSE_BIT)
+
+/* Get/set size at footer */
+#define get_foot(p, s)  (((mchunkptr)((char*)(p) + (s)))->prev_foot)
+#define set_foot(p, s)  (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s))
+
+/* Set size, pinuse bit, and foot */
+#define set_size_and_pinuse_of_free_chunk(p, s)\
+  ((p)->head = (s|PINUSE_BIT), set_foot(p, s))
+
+/* Set size, pinuse bit, foot, and clear next pinuse */
+#define set_free_with_pinuse(p, s, n)\
+  (clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s))
+
+#define is_mmapped(p)\
+  (!((p)->head & PINUSE_BIT) && ((p)->prev_foot & IS_MMAPPED_BIT))
+
+/* Get the internal overhead associated with chunk p */
+#define overhead_for(p)\
+ (is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD)
+
+/* Return true if malloced space is not necessarily cleared */
+#if MMAP_CLEARS
+#define calloc_must_clear(p) (!is_mmapped(p))
+#else /* MMAP_CLEARS */
+#define calloc_must_clear(p) (1)
+#endif /* MMAP_CLEARS */
+
+/* ---------------------- Overlaid data structures ----------------------- */
+
+/*
+  When chunks are not in use, they are treated as nodes of either
+  lists or trees.
+
+  "Small"  chunks are stored in circular doubly-linked lists, and look
+  like this:
+
+    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Size of previous chunk                            |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    `head:' |             Size of chunk, in bytes                         |P|
+      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Forward pointer to next chunk in list             |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Back pointer to previous chunk in list            |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Unused space (may be 0 bytes long)                .
+            .                                                               .
+            .                                                               |
+nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    `foot:' |             Size of chunk, in bytes                           |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+  Larger chunks are kept in a form of bitwise digital trees (aka
+  tries) keyed on chunksizes.  Because malloc_tree_chunks are only for
+  free chunks greater than 256 bytes, their size doesn't impose any
+  constraints on user chunk sizes.  Each node looks like:
+
+    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Size of previous chunk                            |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    `head:' |             Size of chunk, in bytes                         |P|
+      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Forward pointer to next chunk of same size        |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Back pointer to previous chunk of same size       |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Pointer to left child (child[0])                  |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Pointer to right child (child[1])                 |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Pointer to parent                                 |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             bin index of this chunk                           |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Unused space                                      .
+            .                                                               |
+nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    `foot:' |             Size of chunk, in bytes                           |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+  Each tree holding treenodes is a tree of unique chunk sizes.  Chunks
+  of the same size are arranged in a circularly-linked list, with only
+  the oldest chunk (the next to be used, in our FIFO ordering)
+  actually in the tree.  (Tree members are distinguished by a non-null
+  parent pointer.)  If a chunk with the same size an an existing node
+  is inserted, it is linked off the existing node using pointers that
+  work in the same way as fd/bk pointers of small chunks.
+
+  Each tree contains a power of 2 sized range of chunk sizes (the
+  smallest is 0x100 <= x < 0x180), which is is divided in half at each
+  tree level, with the chunks in the smaller half of the range (0x100
+  <= x < 0x140 for the top nose) in the left subtree and the larger
+  half (0x140 <= x < 0x180) in the right subtree.  This is, of course,
+  done by inspecting individual bits.
+
+  Using these rules, each node's left subtree contains all smaller
+  sizes than its right subtree.  However, the node at the root of each
+  subtree has no particular ordering relationship to either.  (The
+  dividing line between the subtree sizes is based on trie relation.)
+  If we remove the last chunk of a given size from the interior of the
+  tree, we need to replace it with a leaf node.  The tree ordering
+  rules permit a node to be replaced by any leaf below it.
+
+  The smallest chunk in a tree (a common operation in a best-fit
+  allocator) can be found by walking a path to the leftmost leaf in
+  the tree.  Unlike a usual binary tree, where we follow left child
+  pointers until we reach a null, here we follow the right child
+  pointer any time the left one is null, until we reach a leaf with
+  both child pointers null. The smallest chunk in the tree will be
+  somewhere along that path.
+
+  The worst case number of steps to add, find, or remove a node is
+  bounded by the number of bits differentiating chunks within
+  bins. Under current bin calculations, this ranges from 6 up to 21
+  (for 32 bit sizes) or up to 53 (for 64 bit sizes). The typical case
+  is of course much better.
+*/
+
+struct malloc_tree_chunk {
+  /* The first four fields must be compatible with malloc_chunk */
+  size_t                    prev_foot;
+  size_t                    head;
+  struct malloc_tree_chunk* fd;
+  struct malloc_tree_chunk* bk;
+
+  struct malloc_tree_chunk* child[2];
+  struct malloc_tree_chunk* parent;
+  bindex_t                  index;
+};
+
+typedef struct malloc_tree_chunk  tchunk;
+typedef struct malloc_tree_chunk* tchunkptr;
+typedef struct malloc_tree_chunk* tbinptr; /* The type of bins of trees */
+
+/* A little helper macro for trees */
+#define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1])
+
+/* ----------------------------- Segments -------------------------------- */
+
+/*
+  Each malloc space may include non-contiguous segments, held in a
+  list headed by an embedded malloc_segment record representing the
+  top-most space. Segments also include flags holding properties of
+  the space. Large chunks that are directly allocated by mmap are not
+  included in this list. They are instead independently created and
+  destroyed without otherwise keeping track of them.
+
+  Segment management mainly comes into play for spaces allocated by
+  MMAP.  Any call to MMAP might or might not return memory that is
+  adjacent to an existing segment.  MORECORE normally contiguously
+  extends the current space, so this space is almost always adjacent,
+  which is simpler and faster to deal with. (This is why MORECORE is
+  used preferentially to MMAP when both are available -- see
+  sys_alloc.)  When allocating using MMAP, we don't use any of the
+  hinting mechanisms (inconsistently) supported in various
+  implementations of unix mmap, or distinguish reserving from
+  committing memory. Instead, we just ask for space, and exploit
+  contiguity when we get it.  It is probably possible to do
+  better than this on some systems, but no general scheme seems
+  to be significantly better.
+
+  Management entails a simpler variant of the consolidation scheme
+  used for chunks to reduce fragmentation -- new adjacent memory is
+  normally prepended or appended to an existing segment. However,
+  there are limitations compared to chunk consolidation that mostly
+  reflect the fact that segment processing is relatively infrequent
+  (occurring only when getting memory from system) and that we
+  don't expect to have huge numbers of segments:
+
+  * Segments are not indexed, so traversal requires linear scans.  (It
+    would be possible to index these, but is not worth the extra
+    overhead and complexity for most programs on most platforms.)
+  * New segments are only appended to old ones when holding top-most
+    memory; if they cannot be prepended to others, they are held in
+    different segments.
+
+  Except for the top-most segment of an mstate, each segment record
+  is kept at the tail of its segment. Segments are added by pushing
+  segment records onto the list headed by &mstate.seg for the
+  containing mstate.
+
+  Segment flags control allocation/merge/deallocation policies:
+  * If EXTERN_BIT set, then we did not allocate this segment,
+    and so should not try to deallocate or merge with others.
+    (This currently holds only for the initial segment passed
+    into create_mspace_with_base.)
+  * If IS_MMAPPED_BIT set, the segment may be merged with
+    other surrounding mmapped segments and trimmed/de-allocated
+    using munmap.
+  * If neither bit is set, then the segment was obtained using
+    MORECORE so can be merged with surrounding MORECORE'd segments
+    and deallocated/trimmed using MORECORE with negative arguments.
+*/
+
+struct malloc_segment {
+  char*        base;             /* base address */
+  size_t       size;             /* allocated size */
+  struct malloc_segment* next;   /* ptr to next segment */
+  flag_t       sflags;           /* mmap and extern flag */
+};
+
+#define is_mmapped_segment(S)  ((S)->sflags & IS_MMAPPED_BIT)
+#define is_extern_segment(S)   ((S)->sflags & EXTERN_BIT)
+
+typedef struct malloc_segment  msegment;
+typedef struct malloc_segment* msegmentptr;
+
+/* ---------------------------- malloc_state ----------------------------- */
+
+/*
+   A malloc_state holds all of the bookkeeping for a space.
+   The main fields are:
+
+  Top
+    The topmost chunk of the currently active segment. Its size is
+    cached in topsize.  The actual size of topmost space is
+    topsize+TOP_FOOT_SIZE, which includes space reserved for adding
+    fenceposts and segment records if necessary when getting more
+    space from the system.  The size at which to autotrim top is
+    cached from mparams in trim_check, except that it is disabled if
+    an autotrim fails.
+
+  Designated victim (dv)
+    This is the preferred chunk for servicing small requests that
+    don't have exact fits.  It is normally the chunk split off most
+    recently to service another small request.  Its size is cached in
+    dvsize. The link fields of this chunk are not maintained since it
+    is not kept in a bin.
+
+  SmallBins
+    An array of bin headers for free chunks.  These bins hold chunks
+    with sizes less than MIN_LARGE_SIZE bytes. Each bin contains
+    chunks of all the same size, spaced 8 bytes apart.  To simplify
+    use in double-linked lists, each bin header acts as a malloc_chunk
+    pointing to the real first node, if it exists (else pointing to
+    itself).  This avoids special-casing for headers.  But to avoid
+    waste, we allocate only the fd/bk pointers of bins, and then use
+    repositioning tricks to treat these as the fields of a chunk.
+
+  TreeBins
+    Treebins are pointers to the roots of trees holding a range of
+    sizes. There are 2 equally spaced treebins for each power of two
+    from TREE_SHIFT to TREE_SHIFT+16. The last bin holds anything
+    larger.
+
+  Bin maps
+    There is one bit map for small bins ("smallmap") and one for
+    treebins ("treemap).  Each bin sets its bit when non-empty, and
+    clears the bit when empty.  Bit operations are then used to avoid
+    bin-by-bin searching -- nearly all "search" is done without ever
+    looking at bins that won't be selected.  The bit maps
+    conservatively use 32 bits per map word, even if on 64bit system.
+    For a good description of some of the bit-based techniques used
+    here, see Henry S. Warren Jr's book "Hacker's Delight" (and
+    supplement at http://hackersdelight.org/). Many of these are
+    intended to reduce the branchiness of paths through malloc etc, as
+    well as to reduce the number of memory locations read or written.
+
+  Segments
+    A list of segments headed by an embedded malloc_segment record
+    representing the initial space.
+
+  Address check support
+    The least_addr field is the least address ever obtained from
+    MORECORE or MMAP. Attempted frees and reallocs of any address less
+    than this are trapped (unless INSECURE is defined).
+
+  Magic tag
+    A cross-check field that should always hold same value as mparams.magic.
+
+  Flags
+    Bits recording whether to use MMAP, locks, or contiguous MORECORE
+
+  Statistics
+    Each space keeps track of current and maximum system memory
+    obtained via MORECORE or MMAP.
+
+  Locking
+    If USE_LOCKS is defined, the "mutex" lock is acquired and released
+    around every public call using this mspace.
+*/
+
+/* Bin types, widths and sizes */
+#define NSMALLBINS        (32U)
+#define NTREEBINS         (32U)
+#define SMALLBIN_SHIFT    (3U)
+#define SMALLBIN_WIDTH    (SIZE_T_ONE << SMALLBIN_SHIFT)
+#define TREEBIN_SHIFT     (8U)
+#define MIN_LARGE_SIZE    (SIZE_T_ONE << TREEBIN_SHIFT)
+#define MAX_SMALL_SIZE    (MIN_LARGE_SIZE - SIZE_T_ONE)
+#define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD)
+
+struct malloc_state {
+  binmap_t   smallmap;
+  binmap_t   treemap;
+  size_t     dvsize;
+  size_t     topsize;
+  char*      least_addr;
+  mchunkptr  dv;
+  mchunkptr  top;
+  size_t     trim_check;
+  size_t     magic;
+  mchunkptr  smallbins[(NSMALLBINS+1)*2];
+  tbinptr    treebins[NTREEBINS];
+  size_t     footprint;
+#if USE_MAX_ALLOWED_FOOTPRINT
+  size_t     max_allowed_footprint;
+#endif
+  size_t     max_footprint;
+  flag_t     mflags;
+#if USE_LOCKS
+  MLOCK_T    mutex;     /* locate lock among fields that rarely change */
+#endif /* USE_LOCKS */
+  msegment   seg;
+};
+
+typedef struct malloc_state*    mstate;
+
+/* ------------- Global malloc_state and malloc_params ------------------- */
+
+/*
+  malloc_params holds global properties, including those that can be
+  dynamically set using mallopt. There is a single instance, mparams,
+  initialized in init_mparams.
+*/
+
+struct malloc_params {
+  size_t magic;
+  size_t page_size;
+  size_t granularity;
+  size_t mmap_threshold;
+  size_t trim_threshold;
+  flag_t default_mflags;
+};
+
+static struct malloc_params mparams;
+
+/* The global malloc_state used for all non-"mspace" calls */
+static struct malloc_state _gm_
+#if USE_MAX_ALLOWED_FOOTPRINT
+        = { .max_allowed_footprint = MAX_SIZE_T };
+#else
+        ;
+#endif
+
+#define gm                 (&_gm_)
+#define is_global(M)       ((M) == &_gm_)
+#define is_initialized(M)  ((M)->top != 0)
+
+/* -------------------------- system alloc setup ------------------------- */
+
+/* Operations on mflags */
+
+#define use_lock(M)           ((M)->mflags &   USE_LOCK_BIT)
+#define enable_lock(M)        ((M)->mflags |=  USE_LOCK_BIT)
+#define disable_lock(M)       ((M)->mflags &= ~USE_LOCK_BIT)
+
+#define use_mmap(M)           ((M)->mflags &   USE_MMAP_BIT)
+#define enable_mmap(M)        ((M)->mflags |=  USE_MMAP_BIT)
+#define disable_mmap(M)       ((M)->mflags &= ~USE_MMAP_BIT)
+
+#define use_noncontiguous(M)  ((M)->mflags &   USE_NONCONTIGUOUS_BIT)
+#define disable_contiguous(M) ((M)->mflags |=  USE_NONCONTIGUOUS_BIT)
+
+#define set_lock(M,L)\
+ ((M)->mflags = (L)?\
+  ((M)->mflags | USE_LOCK_BIT) :\
+  ((M)->mflags & ~USE_LOCK_BIT))
+
+/* page-align a size */
+#define page_align(S)\
+ (((S) + (mparams.page_size)) & ~(mparams.page_size - SIZE_T_ONE))
+
+/* granularity-align a size */
+#define granularity_align(S)\
+  (((S) + (mparams.granularity)) & ~(mparams.granularity - SIZE_T_ONE))
+
+#define is_page_aligned(S)\
+   (((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0)
+#define is_granularity_aligned(S)\
+   (((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0)
+
+/*  True if segment S holds address A */
+#define segment_holds(S, A)\
+  ((char*)(A) >= S->base && (char*)(A) < S->base + S->size)
+
+/* Return segment holding given address */
+static msegmentptr segment_holding(mstate m, char* addr) {
+  msegmentptr sp = &m->seg;
+  for (;;) {
+    if (addr >= sp->base && addr < sp->base + sp->size)
+      return sp;
+    if ((sp = sp->next) == 0)
+      return 0;
+  }
+}
+
+/* Return true if segment contains a segment link */
+static int has_segment_link(mstate m, msegmentptr ss) {
+  msegmentptr sp = &m->seg;
+  for (;;) {
+    if ((char*)sp >= ss->base && (char*)sp < ss->base + ss->size)
+      return 1;
+    if ((sp = sp->next) == 0)
+      return 0;
+  }
+}
+
+#ifndef MORECORE_CANNOT_TRIM
+#define should_trim(M,s)  ((s) > (M)->trim_check)
+#else  /* MORECORE_CANNOT_TRIM */
+#define should_trim(M,s)  (0)
+#endif /* MORECORE_CANNOT_TRIM */
+
+/*
+  TOP_FOOT_SIZE is padding at the end of a segment, including space
+  that may be needed to place segment records and fenceposts when new
+  noncontiguous segments are added.
+*/
+#define TOP_FOOT_SIZE\
+  (align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE)
+
+
+/* -------------------------------  Hooks -------------------------------- */
+
+/*
+  PREACTION should be defined to return 0 on success, and nonzero on
+  failure. If you are not using locking, you can redefine these to do
+  anything you like.
+*/
+
+#if USE_LOCKS
+
+/* Ensure locks are initialized */
+#define GLOBALLY_INITIALIZE() (mparams.page_size == 0 && init_mparams())
+
+#define PREACTION(M)  ((GLOBALLY_INITIALIZE() || use_lock(M))? ACQUIRE_LOCK(&(M)->mutex) : 0)
+#define POSTACTION(M) { if (use_lock(M)) RELEASE_LOCK(&(M)->mutex); }
+#else /* USE_LOCKS */
+
+#ifndef PREACTION
+#define PREACTION(M) (0)
+#endif  /* PREACTION */
+
+#ifndef POSTACTION
+#define POSTACTION(M)
+#endif  /* POSTACTION */
+
+#endif /* USE_LOCKS */
+
+/*
+  CORRUPTION_ERROR_ACTION is triggered upon detected bad addresses.
+  USAGE_ERROR_ACTION is triggered on detected bad frees and
+  reallocs. The argument p is an address that might have triggered the
+  fault. It is ignored by the two predefined actions, but might be
+  useful in custom actions that try to help diagnose errors.
+*/
+
+#if PROCEED_ON_ERROR
+
+/* A count of the number of corruption errors causing resets */
+int malloc_corruption_error_count;
+
+/* default corruption action */
+static void reset_on_error(mstate m);
+
+#define CORRUPTION_ERROR_ACTION(m)  reset_on_error(m)
+#define USAGE_ERROR_ACTION(m, p)
+
+#else /* PROCEED_ON_ERROR */
+
+#ifndef CORRUPTION_ERROR_ACTION
+#define CORRUPTION_ERROR_ACTION(m) ABORT
+#endif /* CORRUPTION_ERROR_ACTION */
+
+#ifndef USAGE_ERROR_ACTION
+#define USAGE_ERROR_ACTION(m,p) ABORT
+#endif /* USAGE_ERROR_ACTION */
+
+#endif /* PROCEED_ON_ERROR */
+
+/* -------------------------- Debugging setup ---------------------------- */
+
+#if ! DEBUG
+
+#define check_free_chunk(M,P)
+#define check_inuse_chunk(M,P)
+#define check_malloced_chunk(M,P,N)
+#define check_mmapped_chunk(M,P)
+#define check_malloc_state(M)
+#define check_top_chunk(M,P)
+
+#else /* DEBUG */
+#define check_free_chunk(M,P)       do_check_free_chunk(M,P)
+#define check_inuse_chunk(M,P)      do_check_inuse_chunk(M,P)
+#define check_top_chunk(M,P)        do_check_top_chunk(M,P)
+#define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N)
+#define check_mmapped_chunk(M,P)    do_check_mmapped_chunk(M,P)
+#define check_malloc_state(M)       do_check_malloc_state(M)
+
+static void   do_check_any_chunk(mstate m, mchunkptr p);
+static void   do_check_top_chunk(mstate m, mchunkptr p);
+static void   do_check_mmapped_chunk(mstate m, mchunkptr p);
+static void   do_check_inuse_chunk(mstate m, mchunkptr p);
+static void   do_check_free_chunk(mstate m, mchunkptr p);
+static void   do_check_malloced_chunk(mstate m, void* mem, size_t s);
+static void   do_check_tree(mstate m, tchunkptr t);
+static void   do_check_treebin(mstate m, bindex_t i);
+static void   do_check_smallbin(mstate m, bindex_t i);
+static void   do_check_malloc_state(mstate m);
+static int    bin_find(mstate m, mchunkptr x);
+static size_t traverse_and_check(mstate m);
+#endif /* DEBUG */
+
+/* ---------------------------- Indexing Bins ---------------------------- */
+
+#define is_small(s)         (((s) >> SMALLBIN_SHIFT) < NSMALLBINS)
+#define small_index(s)      ((s)  >> SMALLBIN_SHIFT)
+#define small_index2size(i) ((i)  << SMALLBIN_SHIFT)
+#define MIN_SMALL_INDEX     (small_index(MIN_CHUNK_SIZE))
+
+/* addressing by index. See above about smallbin repositioning */
+#define smallbin_at(M, i)   ((sbinptr)((char*)&((M)->smallbins[(i)<<1])))
+#define treebin_at(M,i)     (&((M)->treebins[i]))
+
+/* assign tree index for size S to variable I */
+#if defined(__GNUC__) && defined(i386)
+#define compute_tree_index(S, I)\
+{\
+  size_t X = S >> TREEBIN_SHIFT;\
+  if (X == 0)\
+    I = 0;\
+  else if (X > 0xFFFF)\
+    I = NTREEBINS-1;\
+  else {\
+    unsigned int K;\
+    __asm__("bsrl %1,%0\n\t" : "=r" (K) : "rm"  (X));\
+    I =  (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
+  }\
+}
+#else /* GNUC */
+#define compute_tree_index(S, I)\
+{\
+  size_t X = S >> TREEBIN_SHIFT;\
+  if (X == 0)\
+    I = 0;\
+  else if (X > 0xFFFF)\
+    I = NTREEBINS-1;\
+  else {\
+    unsigned int Y = (unsigned int)X;\
+    unsigned int N = ((Y - 0x100) >> 16) & 8;\
+    unsigned int K = (((Y <<= N) - 0x1000) >> 16) & 4;\
+    N += K;\
+    N += K = (((Y <<= K) - 0x4000) >> 16) & 2;\
+    K = 14 - N + ((Y <<= K) >> 15);\
+    I = (K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1));\
+  }\
+}
+#endif /* GNUC */
+
+/* Bit representing maximum resolved size in a treebin at i */
+#define bit_for_tree_index(i) \
+   (i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2)
+
+/* Shift placing maximum resolved bit in a treebin at i as sign bit */
+#define leftshift_for_tree_index(i) \
+   ((i == NTREEBINS-1)? 0 : \
+    ((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2)))
+
+/* The size of the smallest chunk held in bin with index i */
+#define minsize_for_tree_index(i) \
+   ((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) |  \
+   (((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1)))
+
+
+/* ------------------------ Operations on bin maps ----------------------- */
+
+/* bit corresponding to given index */
+#define idx2bit(i)              ((binmap_t)(1) << (i))
+
+/* Mark/Clear bits with given index */
+#define mark_smallmap(M,i)      ((M)->smallmap |=  idx2bit(i))
+#define clear_smallmap(M,i)     ((M)->smallmap &= ~idx2bit(i))
+#define smallmap_is_marked(M,i) ((M)->smallmap &   idx2bit(i))
+
+#define mark_treemap(M,i)       ((M)->treemap  |=  idx2bit(i))
+#define clear_treemap(M,i)      ((M)->treemap  &= ~idx2bit(i))
+#define treemap_is_marked(M,i)  ((M)->treemap  &   idx2bit(i))
+
+/* index corresponding to given bit */
+
+#if defined(__GNUC__) && defined(i386)
+#define compute_bit2idx(X, I)\
+{\
+  unsigned int J;\
+  __asm__("bsfl %1,%0\n\t" : "=r" (J) : "rm" (X));\
+  I = (bindex_t)J;\
+}
+
+#else /* GNUC */
+#if  USE_BUILTIN_FFS
+#define compute_bit2idx(X, I) I = ffs(X)-1
+
+#else /* USE_BUILTIN_FFS */
+#define compute_bit2idx(X, I)\
+{\
+  unsigned int Y = X - 1;\
+  unsigned int K = Y >> (16-4) & 16;\
+  unsigned int N = K;        Y >>= K;\
+  N += K = Y >> (8-3) &  8;  Y >>= K;\
+  N += K = Y >> (4-2) &  4;  Y >>= K;\
+  N += K = Y >> (2-1) &  2;  Y >>= K;\
+  N += K = Y >> (1-0) &  1;  Y >>= K;\
+  I = (bindex_t)(N + Y);\
+}
+#endif /* USE_BUILTIN_FFS */
+#endif /* GNUC */
+
+/* isolate the least set bit of a bitmap */
+#define least_bit(x)         ((x) & -(x))
+
+/* mask with all bits to left of least bit of x on */
+#define left_bits(x)         ((x<<1) | -(x<<1))
+
+/* mask with all bits to left of or equal to least bit of x on */
+#define same_or_left_bits(x) ((x) | -(x))
+
+
+/* ----------------------- Runtime Check Support ------------------------- */
+
+/*
+  For security, the main invariant is that malloc/free/etc never
+  writes to a static address other than malloc_state, unless static
+  malloc_state itself has been corrupted, which cannot occur via
+  malloc (because of these checks). In essence this means that we
+  believe all pointers, sizes, maps etc held in malloc_state, but
+  check all of those linked or offsetted from other embedded data
+  structures.  These checks are interspersed with main code in a way
+  that tends to minimize their run-time cost.
+
+  When FOOTERS is defined, in addition to range checking, we also
+  verify footer fields of inuse chunks, which can be used guarantee
+  that the mstate controlling malloc/free is intact.  This is a
+  streamlined version of the approach described by William Robertson
+  et al in "Run-time Detection of Heap-based Overflows" LISA'03
+  http://www.usenix.org/events/lisa03/tech/robertson.html The footer
+  of an inuse chunk holds the xor of its mstate and a random seed,
+  that is checked upon calls to free() and realloc().  This is
+  (probablistically) unguessable from outside the program, but can be
+  computed by any code successfully malloc'ing any chunk, so does not
+  itself provide protection against code that has already broken
+  security through some other means.  Unlike Robertson et al, we
+  always dynamically check addresses of all offset chunks (previous,
+  next, etc). This turns out to be cheaper than relying on hashes.
+*/
+
+#if !INSECURE
+/* Check if address a is at least as high as any from MORECORE or MMAP */
+#define ok_address(M, a) ((char*)(a) >= (M)->least_addr)
+/* Check if address of next chunk n is higher than base chunk p */
+#define ok_next(p, n)    ((char*)(p) < (char*)(n))
+/* Check if p has its cinuse bit on */
+#define ok_cinuse(p)     cinuse(p)
+/* Check if p has its pinuse bit on */
+#define ok_pinuse(p)     pinuse(p)
+
+#else /* !INSECURE */
+#define ok_address(M, a) (1)
+#define ok_next(b, n)    (1)
+#define ok_cinuse(p)     (1)
+#define ok_pinuse(p)     (1)
+#endif /* !INSECURE */
+
+#if (FOOTERS && !INSECURE)
+/* Check if (alleged) mstate m has expected magic field */
+#define ok_magic(M)      ((M)->magic == mparams.magic)
+#else  /* (FOOTERS && !INSECURE) */
+#define ok_magic(M)      (1)
+#endif /* (FOOTERS && !INSECURE) */
+
+
+/* In gcc, use __builtin_expect to minimize impact of checks */
+#if !INSECURE
+#if defined(__GNUC__) && __GNUC__ >= 3
+#define RTCHECK(e)  __builtin_expect(e, 1)
+#else /* GNUC */
+#define RTCHECK(e)  (e)
+#endif /* GNUC */
+#else /* !INSECURE */
+#define RTCHECK(e)  (1)
+#endif /* !INSECURE */
+
+/* macros to set up inuse chunks with or without footers */
+
+#if !FOOTERS
+
+#define mark_inuse_foot(M,p,s)
+
+/* Set cinuse bit and pinuse bit of next chunk */
+#define set_inuse(M,p,s)\
+  ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
+  ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
+
+/* Set cinuse and pinuse of this chunk and pinuse of next chunk */
+#define set_inuse_and_pinuse(M,p,s)\
+  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
+  ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
+
+/* Set size, cinuse and pinuse bit of this chunk */
+#define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
+  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT))
+
+#else /* FOOTERS */
+
+/* Set foot of inuse chunk to be xor of mstate and seed */
+#define mark_inuse_foot(M,p,s)\
+  (((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic))
+
+#define get_mstate_for(p)\
+  ((mstate)(((mchunkptr)((char*)(p) +\
+    (chunksize(p))))->prev_foot ^ mparams.magic))
+
+#define set_inuse(M,p,s)\
+  ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
+  (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \
+  mark_inuse_foot(M,p,s))
+
+#define set_inuse_and_pinuse(M,p,s)\
+  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
+  (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\
+ mark_inuse_foot(M,p,s))
+
+#define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
+  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
+  mark_inuse_foot(M, p, s))
+
+#endif /* !FOOTERS */
+
+/* ---------------------------- setting mparams -------------------------- */
+
+/* Initialize mparams */
+static int init_mparams(void) {
+  if (mparams.page_size == 0) {
+    size_t s;
+
+    mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD;
+    mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD;
+#if MORECORE_CONTIGUOUS
+    mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT;
+#else  /* MORECORE_CONTIGUOUS */
+    mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT|USE_NONCONTIGUOUS_BIT;
+#endif /* MORECORE_CONTIGUOUS */
+
+#if (FOOTERS && !INSECURE)
+    {
+#if USE_DEV_RANDOM
+      int fd;
+      unsigned char buf[sizeof(size_t)];
+      /* Try to use /dev/urandom, else fall back on using time */
+      if ((fd = open("/dev/urandom", O_RDONLY)) >= 0 &&
+          read(fd, buf, sizeof(buf)) == sizeof(buf)) {
+        s = *((size_t *) buf);
+        close(fd);
+      }
+      else
+#endif /* USE_DEV_RANDOM */
+        s = (size_t)(time(0) ^ (size_t)0x55555555U);
+
+      s |= (size_t)8U;    /* ensure nonzero */
+      s &= ~(size_t)7U;   /* improve chances of fault for bad values */
+
+    }
+#else /* (FOOTERS && !INSECURE) */
+    s = (size_t)0x58585858U;
+#endif /* (FOOTERS && !INSECURE) */
+    ACQUIRE_MAGIC_INIT_LOCK();
+    if (mparams.magic == 0) {
+      mparams.magic = s;
+      /* Set up lock for main malloc area */
+      INITIAL_LOCK(&gm->mutex);
+      gm->mflags = mparams.default_mflags;
+    }
+    RELEASE_MAGIC_INIT_LOCK();
+
+#ifndef WIN32
+    mparams.page_size = malloc_getpagesize;
+    mparams.granularity = ((DEFAULT_GRANULARITY != 0)?
+                           DEFAULT_GRANULARITY : mparams.page_size);
+#else /* WIN32 */
+    {
+      SYSTEM_INFO system_info;
+      GetSystemInfo(&system_info);
+      mparams.page_size = system_info.dwPageSize;
+      mparams.granularity = system_info.dwAllocationGranularity;
+    }
+#endif /* WIN32 */
+
+    /* Sanity-check configuration:
+       size_t must be unsigned and as wide as pointer type.
+       ints must be at least 4 bytes.
+       alignment must be at least 8.
+       Alignment, min chunk size, and page size must all be powers of 2.
+    */
+    if ((sizeof(size_t) != sizeof(char*)) ||
+        (MAX_SIZE_T < MIN_CHUNK_SIZE)  ||
+        (sizeof(int) < 4)  ||
+        (MALLOC_ALIGNMENT < (size_t)8U) ||
+        ((MALLOC_ALIGNMENT    & (MALLOC_ALIGNMENT-SIZE_T_ONE))    != 0) ||
+        ((MCHUNK_SIZE         & (MCHUNK_SIZE-SIZE_T_ONE))         != 0) ||
+        ((mparams.granularity & (mparams.granularity-SIZE_T_ONE)) != 0) ||
+        ((mparams.page_size   & (mparams.page_size-SIZE_T_ONE))   != 0))
+      ABORT;
+  }
+  return 0;
+}
+
+/* support for mallopt */
+static int change_mparam(int param_number, int value) {
+  size_t val = (size_t)value;
+  init_mparams();
+  switch(param_number) {
+  case M_TRIM_THRESHOLD:
+    mparams.trim_threshold = val;
+    return 1;
+  case M_GRANULARITY:
+    if (val >= mparams.page_size && ((val & (val-1)) == 0)) {
+      mparams.granularity = val;
+      return 1;
+    }
+    else
+      return 0;
+  case M_MMAP_THRESHOLD:
+    mparams.mmap_threshold = val;
+    return 1;
+  default:
+    return 0;
+  }
+}
+
+#if DEBUG
+/* ------------------------- Debugging Support --------------------------- */
+
+/* Check properties of any chunk, whether free, inuse, mmapped etc  */
+static void do_check_any_chunk(mstate m, mchunkptr p) {
+  assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
+  assert(ok_address(m, p));
+}
+
+/* Check properties of top chunk */
+static void do_check_top_chunk(mstate m, mchunkptr p) {
+  msegmentptr sp = segment_holding(m, (char*)p);
+  size_t  sz = chunksize(p);
+  assert(sp != 0);
+  assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
+  assert(ok_address(m, p));
+  assert(sz == m->topsize);
+  assert(sz > 0);
+  assert(sz == ((sp->base + sp->size) - (char*)p) - TOP_FOOT_SIZE);
+  assert(pinuse(p));
+  assert(!next_pinuse(p));
+}
+
+/* Check properties of (inuse) mmapped chunks */
+static void do_check_mmapped_chunk(mstate m, mchunkptr p) {
+  size_t  sz = chunksize(p);
+  size_t len = (sz + (p->prev_foot & ~IS_MMAPPED_BIT) + MMAP_FOOT_PAD);
+  assert(is_mmapped(p));
+  assert(use_mmap(m));
+  assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
+  assert(ok_address(m, p));
+  assert(!is_small(sz));
+  assert((len & (mparams.page_size-SIZE_T_ONE)) == 0);
+  assert(chunk_plus_offset(p, sz)->head == FENCEPOST_HEAD);
+  assert(chunk_plus_offset(p, sz+SIZE_T_SIZE)->head == 0);
+}
+
+/* Check properties of inuse chunks */
+static void do_check_inuse_chunk(mstate m, mchunkptr p) {
+  do_check_any_chunk(m, p);
+  assert(cinuse(p));
+  assert(next_pinuse(p));
+  /* If not pinuse and not mmapped, previous chunk has OK offset */
+  assert(is_mmapped(p) || pinuse(p) || next_chunk(prev_chunk(p)) == p);
+  if (is_mmapped(p))
+    do_check_mmapped_chunk(m, p);
+}
+
+/* Check properties of free chunks */
+static void do_check_free_chunk(mstate m, mchunkptr p) {
+  size_t sz = p->head & ~(PINUSE_BIT|CINUSE_BIT);
+  mchunkptr next = chunk_plus_offset(p, sz);
+  do_check_any_chunk(m, p);
+  assert(!cinuse(p));
+  assert(!next_pinuse(p));
+  assert (!is_mmapped(p));
+  if (p != m->dv && p != m->top) {
+    if (sz >= MIN_CHUNK_SIZE) {
+      assert((sz & CHUNK_ALIGN_MASK) == 0);
+      assert(is_aligned(chunk2mem(p)));
+      assert(next->prev_foot == sz);
+      assert(pinuse(p));
+      assert (next == m->top || cinuse(next));
+      assert(p->fd->bk == p);
+      assert(p->bk->fd == p);
+    }
+    else  /* markers are always of size SIZE_T_SIZE */
+      assert(sz == SIZE_T_SIZE);
+  }
+}
+
+/* Check properties of malloced chunks at the point they are malloced */
+static void do_check_malloced_chunk(mstate m, void* mem, size_t s) {
+  if (mem != 0) {
+    mchunkptr p = mem2chunk(mem);
+    size_t sz = p->head & ~(PINUSE_BIT|CINUSE_BIT);
+    do_check_inuse_chunk(m, p);
+    assert((sz & CHUNK_ALIGN_MASK) == 0);
+    assert(sz >= MIN_CHUNK_SIZE);
+    assert(sz >= s);
+    /* unless mmapped, size is less than MIN_CHUNK_SIZE more than request */
+    assert(is_mmapped(p) || sz < (s + MIN_CHUNK_SIZE));
+  }
+}
+
+/* Check a tree and its subtrees.  */
+static void do_check_tree(mstate m, tchunkptr t) {
+  tchunkptr head = 0;
+  tchunkptr u = t;
+  bindex_t tindex = t->index;
+  size_t tsize = chunksize(t);
+  bindex_t idx;
+  compute_tree_index(tsize, idx);
+  assert(tindex == idx);
+  assert(tsize >= MIN_LARGE_SIZE);
+  assert(tsize >= minsize_for_tree_index(idx));
+  assert((idx == NTREEBINS-1) || (tsize < minsize_for_tree_index((idx+1))));
+
+  do { /* traverse through chain of same-sized nodes */
+    do_check_any_chunk(m, ((mchunkptr)u));
+    assert(u->index == tindex);
+    assert(chunksize(u) == tsize);
+    assert(!cinuse(u));
+    assert(!next_pinuse(u));
+    assert(u->fd->bk == u);
+    assert(u->bk->fd == u);
+    if (u->parent == 0) {
+      assert(u->child[0] == 0);
+      assert(u->child[1] == 0);
+    }
+    else {
+      assert(head == 0); /* only one node on chain has parent */
+      head = u;
+      assert(u->parent != u);
+      assert (u->parent->child[0] == u ||
+              u->parent->child[1] == u ||
+              *((tbinptr*)(u->parent)) == u);
+      if (u->child[0] != 0) {
+        assert(u->child[0]->parent == u);
+        assert(u->child[0] != u);
+        do_check_tree(m, u->child[0]);
+      }
+      if (u->child[1] != 0) {
+        assert(u->child[1]->parent == u);
+        assert(u->child[1] != u);
+        do_check_tree(m, u->child[1]);
+      }
+      if (u->child[0] != 0 && u->child[1] != 0) {
+        assert(chunksize(u->child[0]) < chunksize(u->child[1]));
+      }
+    }
+    u = u->fd;
+  } while (u != t);
+  assert(head != 0);
+}
+
+/*  Check all the chunks in a treebin.  */
+static void do_check_treebin(mstate m, bindex_t i) {
+  tbinptr* tb = treebin_at(m, i);
+  tchunkptr t = *tb;
+  int empty = (m->treemap & (1U << i)) == 0;
+  if (t == 0)
+    assert(empty);
+  if (!empty)
+    do_check_tree(m, t);
+}
+
+/*  Check all the chunks in a smallbin.  */
+static void do_check_smallbin(mstate m, bindex_t i) {
+  sbinptr b = smallbin_at(m, i);
+  mchunkptr p = b->bk;
+  unsigned int empty = (m->smallmap & (1U << i)) == 0;
+  if (p == b)
+    assert(empty);
+  if (!empty) {
+    for (; p != b; p = p->bk) {
+      size_t size = chunksize(p);
+      mchunkptr q;
+      /* each chunk claims to be free */
+      do_check_free_chunk(m, p);
+      /* chunk belongs in bin */
+      assert(small_index(size) == i);
+      assert(p->bk == b || chunksize(p->bk) == chunksize(p));
+      /* chunk is followed by an inuse chunk */
+      q = next_chunk(p);
+      if (q->head != FENCEPOST_HEAD)
+        do_check_inuse_chunk(m, q);
+    }
+  }
+}
+
+/* Find x in a bin. Used in other check functions. */
+static int bin_find(mstate m, mchunkptr x) {
+  size_t size = chunksize(x);
+  if (is_small(size)) {
+    bindex_t sidx = small_index(size);
+    sbinptr b = smallbin_at(m, sidx);
+    if (smallmap_is_marked(m, sidx)) {
+      mchunkptr p = b;
+      do {
+        if (p == x)
+          return 1;
+      } while ((p = p->fd) != b);
+    }
+  }
+  else {
+    bindex_t tidx;
+    compute_tree_index(size, tidx);
+    if (treemap_is_marked(m, tidx)) {
+      tchunkptr t = *treebin_at(m, tidx);
+      size_t sizebits = size << leftshift_for_tree_index(tidx);
+      while (t != 0 && chunksize(t) != size) {
+        t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
+        sizebits <<= 1;
+      }
+      if (t != 0) {
+        tchunkptr u = t;
+        do {
+          if (u == (tchunkptr)x)
+            return 1;
+        } while ((u = u->fd) != t);
+      }
+    }
+  }
+  return 0;
+}
+
+/* Traverse each chunk and check it; return total */
+static size_t traverse_and_check(mstate m) {
+  size_t sum = 0;
+  if (is_initialized(m)) {
+    msegmentptr s = &m->seg;
+    sum += m->topsize + TOP_FOOT_SIZE;
+    while (s != 0) {
+      mchunkptr q = align_as_chunk(s->base);
+      mchunkptr lastq = 0;
+      assert(pinuse(q));
+      while (segment_holds(s, q) &&
+             q != m->top && q->head != FENCEPOST_HEAD) {
+        sum += chunksize(q);
+        if (cinuse(q)) {
+          assert(!bin_find(m, q));
+          do_check_inuse_chunk(m, q);
+        }
+        else {
+          assert(q == m->dv || bin_find(m, q));
+          assert(lastq == 0 || cinuse(lastq)); /* Not 2 consecutive free */
+          do_check_free_chunk(m, q);
+        }
+        lastq = q;
+        q = next_chunk(q);
+      }
+      s = s->next;
+    }
+  }
+  return sum;
+}
+
+/* Check all properties of malloc_state. */
+static void do_check_malloc_state(mstate m) {
+  bindex_t i;
+  size_t total;
+  /* check bins */
+  for (i = 0; i < NSMALLBINS; ++i)
+    do_check_smallbin(m, i);
+  for (i = 0; i < NTREEBINS; ++i)
+    do_check_treebin(m, i);
+
+  if (m->dvsize != 0) { /* check dv chunk */
+    do_check_any_chunk(m, m->dv);
+    assert(m->dvsize == chunksize(m->dv));
+    assert(m->dvsize >= MIN_CHUNK_SIZE);
+    assert(bin_find(m, m->dv) == 0);
+  }
+
+  if (m->top != 0) {   /* check top chunk */
+    do_check_top_chunk(m, m->top);
+    assert(m->topsize == chunksize(m->top));
+    assert(m->topsize > 0);
+    assert(bin_find(m, m->top) == 0);
+  }
+
+  total = traverse_and_check(m);
+  assert(total <= m->footprint);
+  assert(m->footprint <= m->max_footprint);
+#if USE_MAX_ALLOWED_FOOTPRINT
+  //TODO: change these assertions if we allow for shrinking.
+  assert(m->footprint <= m->max_allowed_footprint);
+  assert(m->max_footprint <= m->max_allowed_footprint);
+#endif
+}
+#endif /* DEBUG */
+
+/* ----------------------------- statistics ------------------------------ */
+
+#if !NO_MALLINFO
+static struct mallinfo internal_mallinfo(mstate m) {
+  struct mallinfo nm = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+  if (!PREACTION(m)) {
+    check_malloc_state(m);
+    if (is_initialized(m)) {
+      size_t nfree = SIZE_T_ONE; /* top always free */
+      size_t mfree = m->topsize + TOP_FOOT_SIZE;
+      size_t sum = mfree;
+      msegmentptr s = &m->seg;
+      while (s != 0) {
+        mchunkptr q = align_as_chunk(s->base);
+        while (segment_holds(s, q) &&
+               q != m->top && q->head != FENCEPOST_HEAD) {
+          size_t sz = chunksize(q);
+          sum += sz;
+          if (!cinuse(q)) {
+            mfree += sz;
+            ++nfree;
+          }
+          q = next_chunk(q);
+        }
+        s = s->next;
+      }
+
+      nm.arena    = sum;
+      nm.ordblks  = nfree;
+      nm.hblkhd   = m->footprint - sum;
+      nm.usmblks  = m->max_footprint;
+      nm.uordblks = m->footprint - mfree;
+      nm.fordblks = mfree;
+      nm.keepcost = m->topsize;
+    }
+
+    POSTACTION(m);
+  }
+  return nm;
+}
+#endif /* !NO_MALLINFO */
+
+static void internal_malloc_stats(mstate m) {
+  if (!PREACTION(m)) {
+    size_t maxfp = 0;
+    size_t fp = 0;
+    size_t used = 0;
+    check_malloc_state(m);
+    if (is_initialized(m)) {
+      msegmentptr s = &m->seg;
+      maxfp = m->max_footprint;
+      fp = m->footprint;
+      used = fp - (m->topsize + TOP_FOOT_SIZE);
+
+      while (s != 0) {
+        mchunkptr q = align_as_chunk(s->base);
+        while (segment_holds(s, q) &&
+               q != m->top && q->head != FENCEPOST_HEAD) {
+          if (!cinuse(q))
+            used -= chunksize(q);
+          q = next_chunk(q);
+        }
+        s = s->next;
+      }
+    }
+
+    fprintf(stderr, "max system bytes = %10lu\n", (unsigned long)(maxfp));
+    fprintf(stderr, "system bytes     = %10lu\n", (unsigned long)(fp));
+    fprintf(stderr, "in use bytes     = %10lu\n", (unsigned long)(used));
+
+    POSTACTION(m);
+  }
+}
+
+/* ----------------------- Operations on smallbins ----------------------- */
+
+/*
+  Various forms of linking and unlinking are defined as macros.  Even
+  the ones for trees, which are very long but have very short typical
+  paths.  This is ugly but reduces reliance on inlining support of
+  compilers.
+*/
+
+/* Link a free chunk into a smallbin  */
+#define insert_small_chunk(M, P, S) {\
+  bindex_t I  = small_index(S);\
+  mchunkptr B = smallbin_at(M, I);\
+  mchunkptr F = B;\
+  assert(S >= MIN_CHUNK_SIZE);\
+  if (!smallmap_is_marked(M, I))\
+    mark_smallmap(M, I);\
+  else if (RTCHECK(ok_address(M, B->fd)))\
+    F = B->fd;\
+  else {\
+    CORRUPTION_ERROR_ACTION(M);\
+  }\
+  B->fd = P;\
+  F->bk = P;\
+  P->fd = F;\
+  P->bk = B;\
+}
+
+/* Unlink a chunk from a smallbin
+ * Added check: if F->bk != P or B->fd != P, we have double linked list
+ * corruption, and abort.
+ */
+#define unlink_small_chunk(M, P, S) {\
+  mchunkptr F = P->fd;\
+  mchunkptr B = P->bk;\
+  bindex_t I = small_index(S);\
+  if (__builtin_expect (F->bk != P || B->fd != P, 0))\
+    CORRUPTION_ERROR_ACTION(M);\
+  assert(P != B);\
+  assert(P != F);\
+  assert(chunksize(P) == small_index2size(I));\
+  if (F == B)\
+    clear_smallmap(M, I);\
+  else if (RTCHECK((F == smallbin_at(M,I) || ok_address(M, F)) &&\
+                   (B == smallbin_at(M,I) || ok_address(M, B)))) {\
+    F->bk = B;\
+    B->fd = F;\
+  }\
+  else {\
+    CORRUPTION_ERROR_ACTION(M);\
+  }\
+}
+
+/* Unlink the first chunk from a smallbin
+ * Added check: if F->bk != P or B->fd != P, we have double linked list
+ * corruption, and abort.
+ */
+#define unlink_first_small_chunk(M, B, P, I) {\
+  mchunkptr F = P->fd;\
+  if (__builtin_expect (F->bk != P || B->fd != P, 0))\
+    CORRUPTION_ERROR_ACTION(M);\
+  assert(P != B);\
+  assert(P != F);\
+  assert(chunksize(P) == small_index2size(I));\
+  if (B == F)\
+    clear_smallmap(M, I);\
+  else if (RTCHECK(ok_address(M, F))) {\
+    B->fd = F;\
+    F->bk = B;\
+  }\
+  else {\
+    CORRUPTION_ERROR_ACTION(M);\
+  }\
+}
+
+/* Replace dv node, binning the old one */
+/* Used only when dvsize known to be small */
+#define replace_dv(M, P, S) {\
+  size_t DVS = M->dvsize;\
+  if (DVS != 0) {\
+    mchunkptr DV = M->dv;\
+    assert(is_small(DVS));\
+    insert_small_chunk(M, DV, DVS);\
+  }\
+  M->dvsize = S;\
+  M->dv = P;\
+}
+
+/* ------------------------- Operations on trees ------------------------- */
+
+/* Insert chunk into tree */
+#define insert_large_chunk(M, X, S) {\
+  tbinptr* H;\
+  bindex_t I;\
+  compute_tree_index(S, I);\
+  H = treebin_at(M, I);\
+  X->index = I;\
+  X->child[0] = X->child[1] = 0;\
+  if (!treemap_is_marked(M, I)) {\
+    mark_treemap(M, I);\
+    *H = X;\
+    X->parent = (tchunkptr)H;\
+    X->fd = X->bk = X;\
+  }\
+  else {\
+    tchunkptr T = *H;\
+    size_t K = S << leftshift_for_tree_index(I);\
+    for (;;) {\
+      if (chunksize(T) != S) {\
+        tchunkptr* C = &(T->child[(K >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]);\
+        K <<= 1;\
+        if (*C != 0)\
+          T = *C;\
+        else if (RTCHECK(ok_address(M, C))) {\
+          *C = X;\
+          X->parent = T;\
+          X->fd = X->bk = X;\
+          break;\
+        }\
+        else {\
+          CORRUPTION_ERROR_ACTION(M);\
+          break;\
+        }\
+      }\
+      else {\
+        tchunkptr F = T->fd;\
+        if (RTCHECK(ok_address(M, T) && ok_address(M, F))) {\
+          T->fd = F->bk = X;\
+          X->fd = F;\
+          X->bk = T;\
+          X->parent = 0;\
+          break;\
+        }\
+        else {\
+          CORRUPTION_ERROR_ACTION(M);\
+          break;\
+        }\
+      }\
+    }\
+  }\
+}
+
+/*
+  Unlink steps:
+
+  1. If x is a chained node, unlink it from its same-sized fd/bk links
+     and choose its bk node as its replacement.
+  2. If x was the last node of its size, but not a leaf node, it must
+     be replaced with a leaf node (not merely one with an open left or
+     right), to make sure that lefts and rights of descendents
+     correspond properly to bit masks.  We use the rightmost descendent
+     of x.  We could use any other leaf, but this is easy to locate and
+     tends to counteract removal of leftmosts elsewhere, and so keeps
+     paths shorter than minimally guaranteed.  This doesn't loop much
+     because on average a node in a tree is near the bottom.
+  3. If x is the base of a chain (i.e., has parent links) relink
+     x's parent and children to x's replacement (or null if none).
+
+  Added check: if F->bk != X or R->fd != X, we have double linked list
+  corruption, and abort.
+*/
+
+#define unlink_large_chunk(M, X) {\
+  tchunkptr XP = X->parent;\
+  tchunkptr R;\
+  if (X->bk != X) {\
+    tchunkptr F = X->fd;\
+    R = X->bk;\
+    if (__builtin_expect (F->bk != X || R->fd != X, 0))\
+      CORRUPTION_ERROR_ACTION(M);\
+    if (RTCHECK(ok_address(M, F))) {\
+      F->bk = R;\
+      R->fd = F;\
+    }\
+    else {\
+      CORRUPTION_ERROR_ACTION(M);\
+    }\
+  }\
+  else {\
+    tchunkptr* RP;\
+    if (((R = *(RP = &(X->child[1]))) != 0) ||\
+        ((R = *(RP = &(X->child[0]))) != 0)) {\
+      tchunkptr* CP;\
+      while ((*(CP = &(R->child[1])) != 0) ||\
+             (*(CP = &(R->child[0])) != 0)) {\
+        R = *(RP = CP);\
+      }\
+      if (RTCHECK(ok_address(M, RP)))\
+        *RP = 0;\
+      else {\
+        CORRUPTION_ERROR_ACTION(M);\
+      }\
+    }\
+  }\
+  if (XP != 0) {\
+    tbinptr* H = treebin_at(M, X->index);\
+    if (X == *H) {\
+      if ((*H = R) == 0) \
+        clear_treemap(M, X->index);\
+    }\
+    else if (RTCHECK(ok_address(M, XP))) {\
+      if (XP->child[0] == X) \
+        XP->child[0] = R;\
+      else \
+        XP->child[1] = R;\
+    }\
+    else\
+      CORRUPTION_ERROR_ACTION(M);\
+    if (R != 0) {\
+      if (RTCHECK(ok_address(M, R))) {\
+        tchunkptr C0, C1;\
+        R->parent = XP;\
+        if ((C0 = X->child[0]) != 0) {\
+          if (RTCHECK(ok_address(M, C0))) {\
+            R->child[0] = C0;\
+            C0->parent = R;\
+          }\
+          else\
+            CORRUPTION_ERROR_ACTION(M);\
+        }\
+        if ((C1 = X->child[1]) != 0) {\
+          if (RTCHECK(ok_address(M, C1))) {\
+            R->child[1] = C1;\
+            C1->parent = R;\
+          }\
+          else\
+            CORRUPTION_ERROR_ACTION(M);\
+        }\
+      }\
+      else\
+        CORRUPTION_ERROR_ACTION(M);\
+    }\
+  }\
+}
+
+/* Relays to large vs small bin operations */
+
+#define insert_chunk(M, P, S)\
+  if (is_small(S)) insert_small_chunk(M, P, S)\
+  else { tchunkptr TP = (tchunkptr)(P); insert_large_chunk(M, TP, S); }
+
+#define unlink_chunk(M, P, S)\
+  if (is_small(S)) unlink_small_chunk(M, P, S)\
+  else { tchunkptr TP = (tchunkptr)(P); unlink_large_chunk(M, TP); }
+
+
+/* Relays to internal calls to malloc/free from realloc, memalign etc */
+
+#if ONLY_MSPACES
+#define internal_malloc(m, b) mspace_malloc(m, b)
+#define internal_free(m, mem) mspace_free(m,mem);
+#else /* ONLY_MSPACES */
+#if MSPACES
+#define internal_malloc(m, b)\
+   (m == gm)? dlmalloc(b) : mspace_malloc(m, b)
+#define internal_free(m, mem)\
+   if (m == gm) dlfree(mem); else mspace_free(m,mem);
+#else /* MSPACES */
+#define internal_malloc(m, b) dlmalloc(b)
+#define internal_free(m, mem) dlfree(mem)
+#endif /* MSPACES */
+#endif /* ONLY_MSPACES */
+
+/* -----------------------  Direct-mmapping chunks ----------------------- */
+
+/*
+  Directly mmapped chunks are set up with an offset to the start of
+  the mmapped region stored in the prev_foot field of the chunk. This
+  allows reconstruction of the required argument to MUNMAP when freed,
+  and also allows adjustment of the returned chunk to meet alignment
+  requirements (especially in memalign).  There is also enough space
+  allocated to hold a fake next chunk of size SIZE_T_SIZE to maintain
+  the PINUSE bit so frees can be checked.
+*/
+
+/* Malloc using mmap */
+static void* mmap_alloc(mstate m, size_t nb) {
+  size_t mmsize = granularity_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
+#if USE_MAX_ALLOWED_FOOTPRINT
+  size_t new_footprint = m->footprint + mmsize;
+  if (new_footprint <= m->footprint ||  /* Check for wrap around 0 */
+      new_footprint > m->max_allowed_footprint)
+    return 0;
+#endif
+  if (mmsize > nb) {     /* Check for wrap around 0 */
+    char* mm = (char*)(DIRECT_MMAP(mmsize));
+    if (mm != CMFAIL) {
+      size_t offset = align_offset(chunk2mem(mm));
+      size_t psize = mmsize - offset - MMAP_FOOT_PAD;
+      mchunkptr p = (mchunkptr)(mm + offset);
+      p->prev_foot = offset | IS_MMAPPED_BIT;
+      (p)->head = (psize|CINUSE_BIT);
+      mark_inuse_foot(m, p, psize);
+      chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD;
+      chunk_plus_offset(p, psize+SIZE_T_SIZE)->head = 0;
+
+      if (mm < m->least_addr)
+        m->least_addr = mm;
+      if ((m->footprint += mmsize) > m->max_footprint)
+        m->max_footprint = m->footprint;
+      assert(is_aligned(chunk2mem(p)));
+      check_mmapped_chunk(m, p);
+      return chunk2mem(p);
+    }
+  }
+  return 0;
+}
+
+/* Realloc using mmap */
+static mchunkptr mmap_resize(mstate m, mchunkptr oldp, size_t nb) {
+  size_t oldsize = chunksize(oldp);
+  if (is_small(nb)) /* Can't shrink mmap regions below small size */
+    return 0;
+  /* Keep old chunk if big enough but not too big */
+  if (oldsize >= nb + SIZE_T_SIZE &&
+      (oldsize - nb) <= (mparams.granularity << 1))
+    return oldp;
+  else {
+    size_t offset = oldp->prev_foot & ~IS_MMAPPED_BIT;
+    size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD;
+    size_t newmmsize = granularity_align(nb + SIX_SIZE_T_SIZES +
+                                         CHUNK_ALIGN_MASK);
+    char* cp = (char*)CALL_MREMAP((char*)oldp - offset,
+                                  oldmmsize, newmmsize, 1);
+    if (cp != CMFAIL) {
+      mchunkptr newp = (mchunkptr)(cp + offset);
+      size_t psize = newmmsize - offset - MMAP_FOOT_PAD;
+      newp->head = (psize|CINUSE_BIT);
+      mark_inuse_foot(m, newp, psize);
+      chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD;
+      chunk_plus_offset(newp, psize+SIZE_T_SIZE)->head = 0;
+
+      if (cp < m->least_addr)
+        m->least_addr = cp;
+      if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint)
+        m->max_footprint = m->footprint;
+      check_mmapped_chunk(m, newp);
+      return newp;
+    }
+  }
+  return 0;
+}
+
+/* -------------------------- mspace management -------------------------- */
+
+/* Initialize top chunk and its size */
+static void init_top(mstate m, mchunkptr p, size_t psize) {
+  /* Ensure alignment */
+  size_t offset = align_offset(chunk2mem(p));
+  p = (mchunkptr)((char*)p + offset);
+  psize -= offset;
+
+  m->top = p;
+  m->topsize = psize;
+  p->head = psize | PINUSE_BIT;
+  /* set size of fake trailing chunk holding overhead space only once */
+  chunk_plus_offset(p, psize)->head = TOP_FOOT_SIZE;
+  m->trim_check = mparams.trim_threshold; /* reset on each update */
+}
+
+/* Initialize bins for a new mstate that is otherwise zeroed out */
+static void init_bins(mstate m) {
+  /* Establish circular links for smallbins */
+  bindex_t i;
+  for (i = 0; i < NSMALLBINS; ++i) {
+    sbinptr bin = smallbin_at(m,i);
+    bin->fd = bin->bk = bin;
+  }
+}
+
+#if PROCEED_ON_ERROR
+
+/* default corruption action */
+static void reset_on_error(mstate m) {
+  int i;
+  ++malloc_corruption_error_count;
+  /* Reinitialize fields to forget about all memory */
+  m->smallbins = m->treebins = 0;
+  m->dvsize = m->topsize = 0;
+  m->seg.base = 0;
+  m->seg.size = 0;
+  m->seg.next = 0;
+  m->top = m->dv = 0;
+  for (i = 0; i < NTREEBINS; ++i)
+    *treebin_at(m, i) = 0;
+  init_bins(m);
+}
+#endif /* PROCEED_ON_ERROR */
+
+/* Allocate chunk and prepend remainder with chunk in successor base. */
+static void* prepend_alloc(mstate m, char* newbase, char* oldbase,
+                           size_t nb) {
+  mchunkptr p = align_as_chunk(newbase);
+  mchunkptr oldfirst = align_as_chunk(oldbase);
+  size_t psize = (char*)oldfirst - (char*)p;
+  mchunkptr q = chunk_plus_offset(p, nb);
+  size_t qsize = psize - nb;
+  set_size_and_pinuse_of_inuse_chunk(m, p, nb);
+
+  assert((char*)oldfirst > (char*)q);
+  assert(pinuse(oldfirst));
+  assert(qsize >= MIN_CHUNK_SIZE);
+
+  /* consolidate remainder with first chunk of old base */
+  if (oldfirst == m->top) {
+    size_t tsize = m->topsize += qsize;
+    m->top = q;
+    q->head = tsize | PINUSE_BIT;
+    check_top_chunk(m, q);
+  }
+  else if (oldfirst == m->dv) {
+    size_t dsize = m->dvsize += qsize;
+    m->dv = q;
+    set_size_and_pinuse_of_free_chunk(q, dsize);
+  }
+  else {
+    if (!cinuse(oldfirst)) {
+      size_t nsize = chunksize(oldfirst);
+      unlink_chunk(m, oldfirst, nsize);
+      oldfirst = chunk_plus_offset(oldfirst, nsize);
+      qsize += nsize;
+    }
+    set_free_with_pinuse(q, qsize, oldfirst);
+    insert_chunk(m, q, qsize);
+    check_free_chunk(m, q);
+  }
+
+  check_malloced_chunk(m, chunk2mem(p), nb);
+  return chunk2mem(p);
+}
+
+
+/* Add a segment to hold a new noncontiguous region */
+static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) {
+  /* Determine locations and sizes of segment, fenceposts, old top */
+  char* old_top = (char*)m->top;
+  msegmentptr oldsp = segment_holding(m, old_top);
+  char* old_end = oldsp->base + oldsp->size;
+  size_t ssize = pad_request(sizeof(struct malloc_segment));
+  char* rawsp = old_end - (ssize + FOUR_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
+  size_t offset = align_offset(chunk2mem(rawsp));
+  char* asp = rawsp + offset;
+  char* csp = (asp < (old_top + MIN_CHUNK_SIZE))? old_top : asp;
+  mchunkptr sp = (mchunkptr)csp;
+  msegmentptr ss = (msegmentptr)(chunk2mem(sp));
+  mchunkptr tnext = chunk_plus_offset(sp, ssize);
+  mchunkptr p = tnext;
+  int nfences = 0;
+
+  /* reset top to new space */
+  init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
+
+  /* Set up segment record */
+  assert(is_aligned(ss));
+  set_size_and_pinuse_of_inuse_chunk(m, sp, ssize);
+  *ss = m->seg; /* Push current record */
+  m->seg.base = tbase;
+  m->seg.size = tsize;
+  m->seg.sflags = mmapped;
+  m->seg.next = ss;
+
+  /* Insert trailing fenceposts */
+  for (;;) {
+    mchunkptr nextp = chunk_plus_offset(p, SIZE_T_SIZE);
+    p->head = FENCEPOST_HEAD;
+    ++nfences;
+    if ((char*)(&(nextp->head)) < old_end)
+      p = nextp;
+    else
+      break;
+  }
+  assert(nfences >= 2);
+
+  /* Insert the rest of old top into a bin as an ordinary free chunk */
+  if (csp != old_top) {
+    mchunkptr q = (mchunkptr)old_top;
+    size_t psize = csp - old_top;
+    mchunkptr tn = chunk_plus_offset(q, psize);
+    set_free_with_pinuse(q, psize, tn);
+    insert_chunk(m, q, psize);
+  }
+
+  check_top_chunk(m, m->top);
+}
+
+/* -------------------------- System allocation -------------------------- */
+
+/* Get memory from system using MORECORE or MMAP */
+static void* sys_alloc(mstate m, size_t nb) {
+  char* tbase = CMFAIL;
+  size_t tsize = 0;
+  flag_t mmap_flag = 0;
+
+  init_mparams();
+
+  /* Directly map large chunks */
+  if (use_mmap(m) && nb >= mparams.mmap_threshold) {
+    void* mem = mmap_alloc(m, nb);
+    if (mem != 0)
+      return mem;
+  }
+
+#if USE_MAX_ALLOWED_FOOTPRINT
+  /* Make sure the footprint doesn't grow past max_allowed_footprint.
+   * This covers all cases except for where we need to page align, below.
+   */
+  {
+    size_t new_footprint = m->footprint +
+                           granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE);
+    if (new_footprint <= m->footprint ||  /* Check for wrap around 0 */
+        new_footprint > m->max_allowed_footprint)
+      return 0;
+  }
+#endif
+
+  /*
+    Try getting memory in any of three ways (in most-preferred to
+    least-preferred order):
+    1. A call to MORECORE that can normally contiguously extend memory.
+       (disabled if not MORECORE_CONTIGUOUS or not HAVE_MORECORE or
+       or main space is mmapped or a previous contiguous call failed)
+    2. A call to MMAP new space (disabled if not HAVE_MMAP).
+       Note that under the default settings, if MORECORE is unable to
+       fulfill a request, and HAVE_MMAP is true, then mmap is
+       used as a noncontiguous system allocator. This is a useful backup
+       strategy for systems with holes in address spaces -- in this case
+       sbrk cannot contiguously expand the heap, but mmap may be able to
+       find space.
+    3. A call to MORECORE that cannot usually contiguously extend memory.
+       (disabled if not HAVE_MORECORE)
+  */
+
+  if (MORECORE_CONTIGUOUS && !use_noncontiguous(m)) {
+    char* br = CMFAIL;
+    msegmentptr ss = (m->top == 0)? 0 : segment_holding(m, (char*)m->top);
+    size_t asize = 0;
+    ACQUIRE_MORECORE_LOCK();
+
+    if (ss == 0) {  /* First time through or recovery */
+      char* base = (char*)CALL_MORECORE(0);
+      if (base != CMFAIL) {
+        asize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE);
+        /* Adjust to end on a page boundary */
+        if (!is_page_aligned(base)) {
+          asize += (page_align((size_t)base) - (size_t)base);
+#if USE_MAX_ALLOWED_FOOTPRINT
+          /* If the alignment pushes us over max_allowed_footprint,
+           * poison the upcoming call to MORECORE and continue.
+           */
+          {
+            size_t new_footprint = m->footprint + asize;
+            if (new_footprint <= m->footprint ||  /* Check for wrap around 0 */
+                new_footprint > m->max_allowed_footprint) {
+              asize = HALF_MAX_SIZE_T;
+            }
+          }
+#endif
+        }
+        /* Can't call MORECORE if size is negative when treated as signed */
+        if (asize < HALF_MAX_SIZE_T &&
+            (br = (char*)(CALL_MORECORE(asize))) == base) {
+          tbase = base;
+          tsize = asize;
+        }
+      }
+    }
+    else {
+      /* Subtract out existing available top space from MORECORE request. */
+      asize = granularity_align(nb - m->topsize + TOP_FOOT_SIZE + SIZE_T_ONE);
+      /* Use mem here only if it did continuously extend old space */
+      if (asize < HALF_MAX_SIZE_T &&
+          (br = (char*)(CALL_MORECORE(asize))) == ss->base+ss->size) {
+        tbase = br;
+        tsize = asize;
+      }
+    }
+
+    if (tbase == CMFAIL) {    /* Cope with partial failure */
+      if (br != CMFAIL) {    /* Try to use/extend the space we did get */
+        if (asize < HALF_MAX_SIZE_T &&
+            asize < nb + TOP_FOOT_SIZE + SIZE_T_ONE) {
+          size_t esize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE - asize);
+          if (esize < HALF_MAX_SIZE_T) {
+            char* end = (char*)CALL_MORECORE(esize);
+            if (end != CMFAIL)
+              asize += esize;
+            else {            /* Can't use; try to release */
+              CALL_MORECORE(-asize);
+              br = CMFAIL;
+            }
+          }
+        }
+      }
+      if (br != CMFAIL) {    /* Use the space we did get */
+        tbase = br;
+        tsize = asize;
+      }
+      else
+        disable_contiguous(m); /* Don't try contiguous path in the future */
+    }
+
+    RELEASE_MORECORE_LOCK();
+  }
+
+  if (HAVE_MMAP && tbase == CMFAIL) {  /* Try MMAP */
+    size_t req = nb + TOP_FOOT_SIZE + SIZE_T_ONE;
+    size_t rsize = granularity_align(req);
+    if (rsize > nb) { /* Fail if wraps around zero */
+      char* mp = (char*)(CALL_MMAP(rsize));
+      if (mp != CMFAIL) {
+        tbase = mp;
+        tsize = rsize;
+        mmap_flag = IS_MMAPPED_BIT;
+      }
+    }
+  }
+
+  if (HAVE_MORECORE && tbase == CMFAIL) { /* Try noncontiguous MORECORE */
+    size_t asize = granularity_align(nb + TOP_FOOT_SIZE + SIZE_T_ONE);
+    if (asize < HALF_MAX_SIZE_T) {
+      char* br = CMFAIL;
+      char* end = CMFAIL;
+      ACQUIRE_MORECORE_LOCK();
+      br = (char*)(CALL_MORECORE(asize));
+      end = (char*)(CALL_MORECORE(0));
+      RELEASE_MORECORE_LOCK();
+      if (br != CMFAIL && end != CMFAIL && br < end) {
+        size_t ssize = end - br;
+        if (ssize > nb + TOP_FOOT_SIZE) {
+          tbase = br;
+          tsize = ssize;
+        }
+      }
+    }
+  }
+
+  if (tbase != CMFAIL) {
+
+    if ((m->footprint += tsize) > m->max_footprint)
+      m->max_footprint = m->footprint;
+
+    if (!is_initialized(m)) { /* first-time initialization */
+      m->seg.base = m->least_addr = tbase;
+      m->seg.size = tsize;
+      m->seg.sflags = mmap_flag;
+      m->magic = mparams.magic;
+      init_bins(m);
+      if (is_global(m))
+        init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
+      else {
+        /* Offset top by embedded malloc_state */
+        mchunkptr mn = next_chunk(mem2chunk(m));
+        init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) -TOP_FOOT_SIZE);
+      }
+    }
+
+    else {
+      /* Try to merge with an existing segment */
+      msegmentptr sp = &m->seg;
+      while (sp != 0 && tbase != sp->base + sp->size)
+        sp = sp->next;
+      if (sp != 0 &&
+          !is_extern_segment(sp) &&
+          (sp->sflags & IS_MMAPPED_BIT) == mmap_flag &&
+          segment_holds(sp, m->top)) { /* append */
+        sp->size += tsize;
+        init_top(m, m->top, m->topsize + tsize);
+      }
+      else {
+        if (tbase < m->least_addr)
+          m->least_addr = tbase;
+        sp = &m->seg;
+        while (sp != 0 && sp->base != tbase + tsize)
+          sp = sp->next;
+        if (sp != 0 &&
+            !is_extern_segment(sp) &&
+            (sp->sflags & IS_MMAPPED_BIT) == mmap_flag) {
+          char* oldbase = sp->base;
+          sp->base = tbase;
+          sp->size += tsize;
+          return prepend_alloc(m, tbase, oldbase, nb);
+        }
+        else
+          add_segment(m, tbase, tsize, mmap_flag);
+      }
+    }
+
+    if (nb < m->topsize) { /* Allocate from new or extended top space */
+      size_t rsize = m->topsize -= nb;
+      mchunkptr p = m->top;
+      mchunkptr r = m->top = chunk_plus_offset(p, nb);
+      r->head = rsize | PINUSE_BIT;
+      set_size_and_pinuse_of_inuse_chunk(m, p, nb);
+      check_top_chunk(m, m->top);
+      check_malloced_chunk(m, chunk2mem(p), nb);
+      return chunk2mem(p);
+    }
+  }
+
+  MALLOC_FAILURE_ACTION;
+  return 0;
+}
+
+/* -----------------------  system deallocation -------------------------- */
+
+/* Unmap and unlink any mmapped segments that don't contain used chunks */
+static size_t release_unused_segments(mstate m) {
+  size_t released = 0;
+  msegmentptr pred = &m->seg;
+  msegmentptr sp = pred->next;
+  while (sp != 0) {
+    char* base = sp->base;
+    size_t size = sp->size;
+    msegmentptr next = sp->next;
+    if (is_mmapped_segment(sp) && !is_extern_segment(sp)) {
+      mchunkptr p = align_as_chunk(base);
+      size_t psize = chunksize(p);
+      /* Can unmap if first chunk holds entire segment and not pinned */
+      if (!cinuse(p) && (char*)p + psize >= base + size - TOP_FOOT_SIZE) {
+        tchunkptr tp = (tchunkptr)p;
+        assert(segment_holds(sp, (char*)sp));
+        if (p == m->dv) {
+          m->dv = 0;
+          m->dvsize = 0;
+        }
+        else {
+          unlink_large_chunk(m, tp);
+        }
+        if (CALL_MUNMAP(base, size) == 0) {
+          released += size;
+          m->footprint -= size;
+          /* unlink obsoleted record */
+          sp = pred;
+          sp->next = next;
+        }
+        else { /* back out if cannot unmap */
+          insert_large_chunk(m, tp, psize);
+        }
+      }
+    }
+    pred = sp;
+    sp = next;
+  }
+  return released;
+}
+
+static int sys_trim(mstate m, size_t pad) {
+  size_t released = 0;
+  if (pad < MAX_REQUEST && is_initialized(m)) {
+    pad += TOP_FOOT_SIZE; /* ensure enough room for segment overhead */
+
+    if (m->topsize > pad) {
+      /* Shrink top space in granularity-size units, keeping at least one */
+      size_t unit = mparams.granularity;
+      size_t extra = ((m->topsize - pad + (unit - SIZE_T_ONE)) / unit -
+                      SIZE_T_ONE) * unit;
+      msegmentptr sp = segment_holding(m, (char*)m->top);
+
+      if (!is_extern_segment(sp)) {
+        if (is_mmapped_segment(sp)) {
+          if (HAVE_MMAP &&
+              sp->size >= extra &&
+              !has_segment_link(m, sp)) { /* can't shrink if pinned */
+#if HAVE_MMAP && HAVE_MREMAP
+            size_t newsize = sp->size - extra;
+#endif
+            /* Prefer mremap, fall back to munmap */
+            if ((CALL_MREMAP(sp->base, sp->size, newsize, 0) != MFAIL) ||
+                (CALL_MUNMAP(sp->base + newsize, extra) == 0)) {
+              released = extra;
+            }
+          }
+        }
+        else if (HAVE_MORECORE) {
+          if (extra >= HALF_MAX_SIZE_T) /* Avoid wrapping negative */
+            extra = (HALF_MAX_SIZE_T) + SIZE_T_ONE - unit;
+          ACQUIRE_MORECORE_LOCK();
+          {
+            /* Make sure end of memory is where we last set it. */
+            char* old_br = (char*)(CALL_MORECORE(0));
+            if (old_br == sp->base + sp->size) {
+              char* rel_br = (char*)(CALL_MORECORE(-extra));
+              char* new_br = (char*)(CALL_MORECORE(0));
+              if (rel_br != CMFAIL && new_br < old_br)
+                released = old_br - new_br;
+            }
+          }
+          RELEASE_MORECORE_LOCK();
+        }
+      }
+
+      if (released != 0) {
+        sp->size -= released;
+        m->footprint -= released;
+        init_top(m, m->top, m->topsize - released);
+        check_top_chunk(m, m->top);
+      }
+    }
+
+    /* Unmap any unused mmapped segments */
+    if (HAVE_MMAP)
+      released += release_unused_segments(m);
+
+    /* On failure, disable autotrim to avoid repeated failed future calls */
+    if (released == 0)
+      m->trim_check = MAX_SIZE_T;
+  }
+
+  return (released != 0)? 1 : 0;
+}
+
+/* ---------------------------- malloc support --------------------------- */
+
+/* allocate a large request from the best fitting chunk in a treebin */
+static void* tmalloc_large(mstate m, size_t nb) {
+  tchunkptr v = 0;
+  size_t rsize = -nb; /* Unsigned negation */
+  tchunkptr t;
+  bindex_t idx;
+  compute_tree_index(nb, idx);
+
+  if ((t = *treebin_at(m, idx)) != 0) {
+    /* Traverse tree for this bin looking for node with size == nb */
+    size_t sizebits = nb << leftshift_for_tree_index(idx);
+    tchunkptr rst = 0;  /* The deepest untaken right subtree */
+    for (;;) {
+      tchunkptr rt;
+      size_t trem = chunksize(t) - nb;
+      if (trem < rsize) {
+        v = t;
+        if ((rsize = trem) == 0)
+          break;
+      }
+      rt = t->child[1];
+      t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
+      if (rt != 0 && rt != t)
+        rst = rt;
+      if (t == 0) {
+        t = rst; /* set t to least subtree holding sizes > nb */
+        break;
+      }
+      sizebits <<= 1;
+    }
+  }
+
+  if (t == 0 && v == 0) { /* set t to root of next non-empty treebin */
+    binmap_t leftbits = left_bits(idx2bit(idx)) & m->treemap;
+    if (leftbits != 0) {
+      bindex_t i;
+      binmap_t leastbit = least_bit(leftbits);
+      compute_bit2idx(leastbit, i);
+      t = *treebin_at(m, i);
+    }
+  }
+
+  while (t != 0) { /* find smallest of tree or subtree */
+    size_t trem = chunksize(t) - nb;
+    if (trem < rsize) {
+      rsize = trem;
+      v = t;
+    }
+    t = leftmost_child(t);
+  }
+
+  /*  If dv is a better fit, return 0 so malloc will use it */
+  if (v != 0 && rsize < (size_t)(m->dvsize - nb)) {
+    if (RTCHECK(ok_address(m, v))) { /* split */
+      mchunkptr r = chunk_plus_offset(v, nb);
+      assert(chunksize(v) == rsize + nb);
+      if (RTCHECK(ok_next(v, r))) {
+        unlink_large_chunk(m, v);
+        if (rsize < MIN_CHUNK_SIZE)
+          set_inuse_and_pinuse(m, v, (rsize + nb));
+        else {
+          set_size_and_pinuse_of_inuse_chunk(m, v, nb);
+          set_size_and_pinuse_of_free_chunk(r, rsize);
+          insert_chunk(m, r, rsize);
+        }
+        return chunk2mem(v);
+      }
+    }
+    CORRUPTION_ERROR_ACTION(m);
+  }
+  return 0;
+}
+
+/* allocate a small request from the best fitting chunk in a treebin */
+static void* tmalloc_small(mstate m, size_t nb) {
+  tchunkptr t, v;
+  size_t rsize;
+  bindex_t i;
+  binmap_t leastbit = least_bit(m->treemap);
+  compute_bit2idx(leastbit, i);
+
+  v = t = *treebin_at(m, i);
+  rsize = chunksize(t) - nb;
+
+  while ((t = leftmost_child(t)) != 0) {
+    size_t trem = chunksize(t) - nb;
+    if (trem < rsize) {
+      rsize = trem;
+      v = t;
+    }
+  }
+
+  if (RTCHECK(ok_address(m, v))) {
+    mchunkptr r = chunk_plus_offset(v, nb);
+    assert(chunksize(v) == rsize + nb);
+    if (RTCHECK(ok_next(v, r))) {
+      unlink_large_chunk(m, v);
+      if (rsize < MIN_CHUNK_SIZE)
+        set_inuse_and_pinuse(m, v, (rsize + nb));
+      else {
+        set_size_and_pinuse_of_inuse_chunk(m, v, nb);
+        set_size_and_pinuse_of_free_chunk(r, rsize);
+        replace_dv(m, r, rsize);
+      }
+      return chunk2mem(v);
+    }
+  }
+
+  CORRUPTION_ERROR_ACTION(m);
+  return 0;
+}
+
+/* --------------------------- realloc support --------------------------- */
+
+static void* internal_realloc(mstate m, void* oldmem, size_t bytes) {
+  if (bytes >= MAX_REQUEST) {
+    MALLOC_FAILURE_ACTION;
+    return 0;
+  }
+  if (!PREACTION(m)) {
+    mchunkptr oldp = mem2chunk(oldmem);
+    size_t oldsize = chunksize(oldp);
+    mchunkptr next = chunk_plus_offset(oldp, oldsize);
+    mchunkptr newp = 0;
+    void* extra = 0;
+
+    /* Try to either shrink or extend into top. Else malloc-copy-free */
+
+    if (RTCHECK(ok_address(m, oldp) && ok_cinuse(oldp) &&
+                ok_next(oldp, next) && ok_pinuse(next))) {
+      size_t nb = request2size(bytes);
+      if (is_mmapped(oldp))
+        newp = mmap_resize(m, oldp, nb);
+      else if (oldsize >= nb) { /* already big enough */
+        size_t rsize = oldsize - nb;
+        newp = oldp;
+        if (rsize >= MIN_CHUNK_SIZE) {
+          mchunkptr remainder = chunk_plus_offset(newp, nb);
+          set_inuse(m, newp, nb);
+          set_inuse(m, remainder, rsize);
+          extra = chunk2mem(remainder);
+        }
+      }
+      else if (next == m->top && oldsize + m->topsize > nb) {
+        /* Expand into top */
+        size_t newsize = oldsize + m->topsize;
+        size_t newtopsize = newsize - nb;
+        mchunkptr newtop = chunk_plus_offset(oldp, nb);
+        set_inuse(m, oldp, nb);
+        newtop->head = newtopsize |PINUSE_BIT;
+        m->top = newtop;
+        m->topsize = newtopsize;
+        newp = oldp;
+      }
+    }
+    else {
+      USAGE_ERROR_ACTION(m, oldmem);
+      POSTACTION(m);
+      return 0;
+    }
+
+    POSTACTION(m);
+
+    if (newp != 0) {
+      if (extra != 0) {
+        internal_free(m, extra);
+      }
+      check_inuse_chunk(m, newp);
+      return chunk2mem(newp);
+    }
+    else {
+      void* newmem = internal_malloc(m, bytes);
+      if (newmem != 0) {
+        size_t oc = oldsize - overhead_for(oldp);
+        memcpy(newmem, oldmem, (oc < bytes)? oc : bytes);
+        internal_free(m, oldmem);
+      }
+      return newmem;
+    }
+  }
+  return 0;
+}
+
+/* --------------------------- memalign support -------------------------- */
+
+static void* internal_memalign(mstate m, size_t alignment, size_t bytes) {
+  if (alignment <= MALLOC_ALIGNMENT)    /* Can just use malloc */
+    return internal_malloc(m, bytes);
+  if (alignment <  MIN_CHUNK_SIZE) /* must be at least a minimum chunk size */
+    alignment = MIN_CHUNK_SIZE;
+  if ((alignment & (alignment-SIZE_T_ONE)) != 0) {/* Ensure a power of 2 */
+    size_t a = MALLOC_ALIGNMENT << 1;
+    while (a < alignment) a <<= 1;
+    alignment = a;
+  }
+
+  if (bytes >= MAX_REQUEST - alignment) {
+    if (m != 0)  { /* Test isn't needed but avoids compiler warning */
+      MALLOC_FAILURE_ACTION;
+    }
+  }
+  else {
+    size_t nb = request2size(bytes);
+    size_t req = nb + alignment + MIN_CHUNK_SIZE - CHUNK_OVERHEAD;
+    char* mem = (char*)internal_malloc(m, req);
+    if (mem != 0) {
+      void* leader = 0;
+      void* trailer = 0;
+      mchunkptr p = mem2chunk(mem);
+
+      if (PREACTION(m)) return 0;
+      if ((((size_t)(mem)) % alignment) != 0) { /* misaligned */
+        /*
+          Find an aligned spot inside chunk.  Since we need to give
+          back leading space in a chunk of at least MIN_CHUNK_SIZE, if
+          the first calculation places us at a spot with less than
+          MIN_CHUNK_SIZE leader, we can move to the next aligned spot.
+          We've allocated enough total room so that this is always
+          possible.
+        */
+        char* br = (char*)mem2chunk((size_t)(((size_t)(mem +
+                                                       alignment -
+                                                       SIZE_T_ONE)) &
+                                             -alignment));
+        char* pos = ((size_t)(br - (char*)(p)) >= MIN_CHUNK_SIZE)?
+          br : br+alignment;
+        mchunkptr newp = (mchunkptr)pos;
+        size_t leadsize = pos - (char*)(p);
+        size_t newsize = chunksize(p) - leadsize;
+
+        if (is_mmapped(p)) { /* For mmapped chunks, just adjust offset */
+          newp->prev_foot = p->prev_foot + leadsize;
+          newp->head = (newsize|CINUSE_BIT);
+        }
+        else { /* Otherwise, give back leader, use the rest */
+          set_inuse(m, newp, newsize);
+          set_inuse(m, p, leadsize);
+          leader = chunk2mem(p);
+        }
+        p = newp;
+      }
+
+      /* Give back spare room at the end */
+      if (!is_mmapped(p)) {
+        size_t size = chunksize(p);
+        if (size > nb + MIN_CHUNK_SIZE) {
+          size_t remainder_size = size - nb;
+          mchunkptr remainder = chunk_plus_offset(p, nb);
+          set_inuse(m, p, nb);
+          set_inuse(m, remainder, remainder_size);
+          trailer = chunk2mem(remainder);
+        }
+      }
+
+      assert (chunksize(p) >= nb);
+      assert((((size_t)(chunk2mem(p))) % alignment) == 0);
+      check_inuse_chunk(m, p);
+      POSTACTION(m);
+      if (leader != 0) {
+        internal_free(m, leader);
+      }
+      if (trailer != 0) {
+        internal_free(m, trailer);
+      }
+      return chunk2mem(p);
+    }
+  }
+  return 0;
+}
+
+/* ------------------------ comalloc/coalloc support --------------------- */
+
+static void** ialloc(mstate m,
+                     size_t n_elements,
+                     size_t* sizes,
+                     int opts,
+                     void* chunks[]) {
+  /*
+    This provides common support for independent_X routines, handling
+    all of the combinations that can result.
+
+    The opts arg has:
+    bit 0 set if all elements are same size (using sizes[0])
+    bit 1 set if elements should be zeroed
+  */
+
+  size_t    element_size;   /* chunksize of each element, if all same */
+  size_t    contents_size;  /* total size of elements */
+  size_t    array_size;     /* request size of pointer array */
+  void*     mem;            /* malloced aggregate space */
+  mchunkptr p;              /* corresponding chunk */
+  size_t    remainder_size; /* remaining bytes while splitting */
+  void**    marray;         /* either "chunks" or malloced ptr array */
+  mchunkptr array_chunk;    /* chunk for malloced ptr array */
+  flag_t    was_enabled;    /* to disable mmap */
+  size_t    size;
+  size_t    i;
+
+  /* compute array length, if needed */
+  if (chunks != 0) {
+    if (n_elements == 0)
+      return chunks; /* nothing to do */
+    marray = chunks;
+    array_size = 0;
+  }
+  else {
+    /* if empty req, must still return chunk representing empty array */
+    if (n_elements == 0)
+      return (void**)internal_malloc(m, 0);
+    marray = 0;
+    array_size = request2size(n_elements * (sizeof(void*)));
+  }
+
+  /* compute total element size */
+  if (opts & 0x1) { /* all-same-size */
+    element_size = request2size(*sizes);
+    contents_size = n_elements * element_size;
+  }
+  else { /* add up all the sizes */
+    element_size = 0;
+    contents_size = 0;
+    for (i = 0; i != n_elements; ++i)
+      contents_size += request2size(sizes[i]);
+  }
+
+  size = contents_size + array_size;
+
+  /*
+     Allocate the aggregate chunk.  First disable direct-mmapping so
+     malloc won't use it, since we would not be able to later
+     free/realloc space internal to a segregated mmap region.
+  */
+  was_enabled = use_mmap(m);
+  disable_mmap(m);
+  mem = internal_malloc(m, size - CHUNK_OVERHEAD);
+  if (was_enabled)
+    enable_mmap(m);
+  if (mem == 0)
+    return 0;
+
+  if (PREACTION(m)) return 0;
+  p = mem2chunk(mem);
+  remainder_size = chunksize(p);
+
+  assert(!is_mmapped(p));
+
+  if (opts & 0x2) {       /* optionally clear the elements */
+    memset((size_t*)mem, 0, remainder_size - SIZE_T_SIZE - array_size);
+  }
+
+  /* If not provided, allocate the pointer array as final part of chunk */
+  if (marray == 0) {
+    size_t  array_chunk_size;
+    array_chunk = chunk_plus_offset(p, contents_size);
+    array_chunk_size = remainder_size - contents_size;
+    marray = (void**) (chunk2mem(array_chunk));
+    set_size_and_pinuse_of_inuse_chunk(m, array_chunk, array_chunk_size);
+    remainder_size = contents_size;
+  }
+
+  /* split out elements */
+  for (i = 0; ; ++i) {
+    marray[i] = chunk2mem(p);
+    if (i != n_elements-1) {
+      if (element_size != 0)
+        size = element_size;
+      else
+        size = request2size(sizes[i]);
+      remainder_size -= size;
+      set_size_and_pinuse_of_inuse_chunk(m, p, size);
+      p = chunk_plus_offset(p, size);
+    }
+    else { /* the final element absorbs any overallocation slop */
+      set_size_and_pinuse_of_inuse_chunk(m, p, remainder_size);
+      break;
+    }
+  }
+
+#if DEBUG
+  if (marray != chunks) {
+    /* final element must have exactly exhausted chunk */
+    if (element_size != 0) {
+      assert(remainder_size == element_size);
+    }
+    else {
+      assert(remainder_size == request2size(sizes[i]));
+    }
+    check_inuse_chunk(m, mem2chunk(marray));
+  }
+  for (i = 0; i != n_elements; ++i)
+    check_inuse_chunk(m, mem2chunk(marray[i]));
+
+#endif /* DEBUG */
+
+  POSTACTION(m);
+  return marray;
+}
+
+
+/* -------------------------- public routines ---------------------------- */
+
+#if !ONLY_MSPACES
+
+void* dlmalloc(size_t bytes) {
+  /*
+     Basic algorithm:
+     If a small request (< 256 bytes minus per-chunk overhead):
+       1. If one exists, use a remainderless chunk in associated smallbin.
+          (Remainderless means that there are too few excess bytes to
+          represent as a chunk.)
+       2. If it is big enough, use the dv chunk, which is normally the
+          chunk adjacent to the one used for the most recent small request.
+       3. If one exists, split the smallest available chunk in a bin,
+          saving remainder in dv.
+       4. If it is big enough, use the top chunk.
+       5. If available, get memory from system and use it
+     Otherwise, for a large request:
+       1. Find the smallest available binned chunk that fits, and use it
+          if it is better fitting than dv chunk, splitting if necessary.
+       2. If better fitting than any binned chunk, use the dv chunk.
+       3. If it is big enough, use the top chunk.
+       4. If request size >= mmap threshold, try to directly mmap this chunk.
+       5. If available, get memory from system and use it
+
+     The ugly goto's here ensure that postaction occurs along all paths.
+  */
+
+  if (!PREACTION(gm)) {
+    void* mem;
+    size_t nb;
+    if (bytes <= MAX_SMALL_REQUEST) {
+      bindex_t idx;
+      binmap_t smallbits;
+      nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
+      idx = small_index(nb);
+      smallbits = gm->smallmap >> idx;
+
+      if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
+        mchunkptr b, p;
+        idx += ~smallbits & 1;       /* Uses next bin if idx empty */
+        b = smallbin_at(gm, idx);
+        p = b->fd;
+        assert(chunksize(p) == small_index2size(idx));
+        unlink_first_small_chunk(gm, b, p, idx);
+        set_inuse_and_pinuse(gm, p, small_index2size(idx));
+        mem = chunk2mem(p);
+        check_malloced_chunk(gm, mem, nb);
+        goto postaction;
+      }
+
+      else if (nb > gm->dvsize) {
+        if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
+          mchunkptr b, p, r;
+          size_t rsize;
+          bindex_t i;
+          binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
+          binmap_t leastbit = least_bit(leftbits);
+          compute_bit2idx(leastbit, i);
+          b = smallbin_at(gm, i);
+          p = b->fd;
+          assert(chunksize(p) == small_index2size(i));
+          unlink_first_small_chunk(gm, b, p, i);
+          rsize = small_index2size(i) - nb;
+          /* Fit here cannot be remainderless if 4byte sizes */
+          if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
+            set_inuse_and_pinuse(gm, p, small_index2size(i));
+          else {
+            set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
+            r = chunk_plus_offset(p, nb);
+            set_size_and_pinuse_of_free_chunk(r, rsize);
+            replace_dv(gm, r, rsize);
+          }
+          mem = chunk2mem(p);
+          check_malloced_chunk(gm, mem, nb);
+          goto postaction;
+        }
+
+        else if (gm->treemap != 0 && (mem = tmalloc_small(gm, nb)) != 0) {
+          check_malloced_chunk(gm, mem, nb);
+          goto postaction;
+        }
+      }
+    }
+    else if (bytes >= MAX_REQUEST)
+      nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
+    else {
+      nb = pad_request(bytes);
+      if (gm->treemap != 0 && (mem = tmalloc_large(gm, nb)) != 0) {
+        check_malloced_chunk(gm, mem, nb);
+        goto postaction;
+      }
+    }
+
+    if (nb <= gm->dvsize) {
+      size_t rsize = gm->dvsize - nb;
+      mchunkptr p = gm->dv;
+      if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
+        mchunkptr r = gm->dv = chunk_plus_offset(p, nb);
+        gm->dvsize = rsize;
+        set_size_and_pinuse_of_free_chunk(r, rsize);
+        set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
+      }
+      else { /* exhaust dv */
+        size_t dvs = gm->dvsize;
+        gm->dvsize = 0;
+        gm->dv = 0;
+        set_inuse_and_pinuse(gm, p, dvs);
+      }
+      mem = chunk2mem(p);
+      check_malloced_chunk(gm, mem, nb);
+      goto postaction;
+    }
+
+    else if (nb < gm->topsize) { /* Split top */
+      size_t rsize = gm->topsize -= nb;
+      mchunkptr p = gm->top;
+      mchunkptr r = gm->top = chunk_plus_offset(p, nb);
+      r->head = rsize | PINUSE_BIT;
+      set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
+      mem = chunk2mem(p);
+      check_top_chunk(gm, gm->top);
+      check_malloced_chunk(gm, mem, nb);
+      goto postaction;
+    }
+
+    mem = sys_alloc(gm, nb);
+
+  postaction:
+    POSTACTION(gm);
+    return mem;
+  }
+
+  return 0;
+}
+
+void dlfree(void* mem) {
+  /*
+     Consolidate freed chunks with preceeding or succeeding bordering
+     free chunks, if they exist, and then place in a bin.  Intermixed
+     with special cases for top, dv, mmapped chunks, and usage errors.
+  */
+
+  if (mem != 0) {
+    mchunkptr p  = mem2chunk(mem);
+#if FOOTERS
+    mstate fm = get_mstate_for(p);
+    if (!ok_magic(fm)) {
+      USAGE_ERROR_ACTION(fm, p);
+      return;
+    }
+#else /* FOOTERS */
+#define fm gm
+#endif /* FOOTERS */
+    if (!PREACTION(fm)) {
+      check_inuse_chunk(fm, p);
+      if (RTCHECK(ok_address(fm, p) && ok_cinuse(p))) {
+        size_t psize = chunksize(p);
+        mchunkptr next = chunk_plus_offset(p, psize);
+        if (!pinuse(p)) {
+          size_t prevsize = p->prev_foot;
+          if ((prevsize & IS_MMAPPED_BIT) != 0) {
+            prevsize &= ~IS_MMAPPED_BIT;
+            psize += prevsize + MMAP_FOOT_PAD;
+            if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
+              fm->footprint -= psize;
+            goto postaction;
+          }
+          else {
+            mchunkptr prev = chunk_minus_offset(p, prevsize);
+            psize += prevsize;
+            p = prev;
+            if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
+              if (p != fm->dv) {
+                unlink_chunk(fm, p, prevsize);
+              }
+              else if ((next->head & INUSE_BITS) == INUSE_BITS) {
+                fm->dvsize = psize;
+                set_free_with_pinuse(p, psize, next);
+                goto postaction;
+              }
+            }
+            else
+              goto erroraction;
+          }
+        }
+
+        if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
+          if (!cinuse(next)) {  /* consolidate forward */
+            if (next == fm->top) {
+              size_t tsize = fm->topsize += psize;
+              fm->top = p;
+              p->head = tsize | PINUSE_BIT;
+              if (p == fm->dv) {
+                fm->dv = 0;
+                fm->dvsize = 0;
+              }
+              if (should_trim(fm, tsize))
+                sys_trim(fm, 0);
+              goto postaction;
+            }
+            else if (next == fm->dv) {
+              size_t dsize = fm->dvsize += psize;
+              fm->dv = p;
+              set_size_and_pinuse_of_free_chunk(p, dsize);
+              goto postaction;
+            }
+            else {
+              size_t nsize = chunksize(next);
+              psize += nsize;
+              unlink_chunk(fm, next, nsize);
+              set_size_and_pinuse_of_free_chunk(p, psize);
+              if (p == fm->dv) {
+                fm->dvsize = psize;
+                goto postaction;
+              }
+            }
+          }
+          else
+            set_free_with_pinuse(p, psize, next);
+          insert_chunk(fm, p, psize);
+          check_free_chunk(fm, p);
+          goto postaction;
+        }
+      }
+    erroraction:
+      USAGE_ERROR_ACTION(fm, p);
+    postaction:
+      POSTACTION(fm);
+    }
+  }
+#if !FOOTERS
+#undef fm
+#endif /* FOOTERS */
+}
+
+void* dlcalloc(size_t n_elements, size_t elem_size) {
+  void *mem;
+  if (n_elements && MAX_SIZE_T / n_elements < elem_size) {
+    /* Fail on overflow */
+    MALLOC_FAILURE_ACTION;
+    return NULL;
+  }
+  elem_size *= n_elements;
+  mem = dlmalloc(elem_size);
+  if (mem && calloc_must_clear(mem2chunk(mem)))
+    memset(mem, 0, elem_size);
+  return mem;
+}
+
+void* dlrealloc(void* oldmem, size_t bytes) {
+  if (oldmem == 0)
+    return dlmalloc(bytes);
+#ifdef REALLOC_ZERO_BYTES_FREES
+  if (bytes == 0) {
+    dlfree(oldmem);
+    return 0;
+  }
+#endif /* REALLOC_ZERO_BYTES_FREES */
+  else {
+#if ! FOOTERS
+    mstate m = gm;
+#else /* FOOTERS */
+    mstate m = get_mstate_for(mem2chunk(oldmem));
+    if (!ok_magic(m)) {
+      USAGE_ERROR_ACTION(m, oldmem);
+      return 0;
+    }
+#endif /* FOOTERS */
+    return internal_realloc(m, oldmem, bytes);
+  }
+}
+
+void* dlmemalign(size_t alignment, size_t bytes) {
+  return internal_memalign(gm, alignment, bytes);
+}
+
+void** dlindependent_calloc(size_t n_elements, size_t elem_size,
+                                 void* chunks[]) {
+  size_t sz = elem_size; /* serves as 1-element array */
+  return ialloc(gm, n_elements, &sz, 3, chunks);
+}
+
+void** dlindependent_comalloc(size_t n_elements, size_t sizes[],
+                                   void* chunks[]) {
+  return ialloc(gm, n_elements, sizes, 0, chunks);
+}
+
+void* dlvalloc(size_t bytes) {
+  size_t pagesz;
+  init_mparams();
+  pagesz = mparams.page_size;
+  return dlmemalign(pagesz, bytes);
+}
+
+void* dlpvalloc(size_t bytes) {
+  size_t pagesz;
+  init_mparams();
+  pagesz = mparams.page_size;
+  return dlmemalign(pagesz, (bytes + pagesz - SIZE_T_ONE) & ~(pagesz - SIZE_T_ONE));
+}
+
+int dlmalloc_trim(size_t pad) {
+  int result = 0;
+  if (!PREACTION(gm)) {
+    result = sys_trim(gm, pad);
+    POSTACTION(gm);
+  }
+  return result;
+}
+
+size_t dlmalloc_footprint(void) {
+  return gm->footprint;
+}
+
+#if USE_MAX_ALLOWED_FOOTPRINT
+size_t dlmalloc_max_allowed_footprint(void) {
+  return gm->max_allowed_footprint;
+}
+
+void dlmalloc_set_max_allowed_footprint(size_t bytes) {
+  if (bytes > gm->footprint) {
+    /* Increase the size in multiples of the granularity,
+     * which is the smallest unit we request from the system.
+     */
+    gm->max_allowed_footprint = gm->footprint +
+                                granularity_align(bytes - gm->footprint);
+  }
+  else {
+    //TODO: allow for reducing the max footprint
+    gm->max_allowed_footprint = gm->footprint;
+  }
+}
+#endif
+
+size_t dlmalloc_max_footprint(void) {
+  return gm->max_footprint;
+}
+
+#if !NO_MALLINFO
+struct mallinfo dlmallinfo(void) {
+  return internal_mallinfo(gm);
+}
+#endif /* NO_MALLINFO */
+
+void dlmalloc_stats() {
+  internal_malloc_stats(gm);
+}
+
+size_t dlmalloc_usable_size(void* mem) {
+  if (mem != 0) {
+    mchunkptr p = mem2chunk(mem);
+    if (cinuse(p))
+      return chunksize(p) - overhead_for(p);
+  }
+  return 0;
+}
+
+int dlmallopt(int param_number, int value) {
+  return change_mparam(param_number, value);
+}
+
+#endif /* !ONLY_MSPACES */
+
+/* ----------------------------- user mspaces ---------------------------- */
+
+#if MSPACES
+
+static mstate init_user_mstate(char* tbase, size_t tsize) {
+  size_t msize = pad_request(sizeof(struct malloc_state));
+  mchunkptr mn;
+  mchunkptr msp = align_as_chunk(tbase);
+  mstate m = (mstate)(chunk2mem(msp));
+  memset(m, 0, msize);
+  INITIAL_LOCK(&m->mutex);
+  msp->head = (msize|PINUSE_BIT|CINUSE_BIT);
+  m->seg.base = m->least_addr = tbase;
+  m->seg.size = m->footprint = m->max_footprint = tsize;
+#if USE_MAX_ALLOWED_FOOTPRINT
+  m->max_allowed_footprint = MAX_SIZE_T;
+#endif
+  m->magic = mparams.magic;
+  m->mflags = mparams.default_mflags;
+  disable_contiguous(m);
+  init_bins(m);
+  mn = next_chunk(mem2chunk(m));
+  init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) - TOP_FOOT_SIZE);
+  check_top_chunk(m, m->top);
+  return m;
+}
+
+mspace create_mspace(size_t capacity, int locked) {
+  mstate m = 0;
+  size_t msize = pad_request(sizeof(struct malloc_state));
+  init_mparams(); /* Ensure pagesize etc initialized */
+
+  if (capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
+    size_t rs = ((capacity == 0)? mparams.granularity :
+                 (capacity + TOP_FOOT_SIZE + msize));
+    size_t tsize = granularity_align(rs);
+    char* tbase = (char*)(CALL_MMAP(tsize));
+    if (tbase != CMFAIL) {
+      m = init_user_mstate(tbase, tsize);
+      m->seg.sflags = IS_MMAPPED_BIT;
+      set_lock(m, locked);
+    }
+  }
+  return (mspace)m;
+}
+
+mspace create_mspace_with_base(void* base, size_t capacity, int locked) {
+  mstate m = 0;
+  size_t msize = pad_request(sizeof(struct malloc_state));
+  init_mparams(); /* Ensure pagesize etc initialized */
+
+  if (capacity > msize + TOP_FOOT_SIZE &&
+      capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
+    m = init_user_mstate((char*)base, capacity);
+    m->seg.sflags = EXTERN_BIT;
+    set_lock(m, locked);
+  }
+  return (mspace)m;
+}
+
+size_t destroy_mspace(mspace msp) {
+  size_t freed = 0;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    msegmentptr sp = &ms->seg;
+    while (sp != 0) {
+#if HAVE_MMAP && HAVE_MREMAP
+      char* base = sp->base;
+#endif
+      size_t size = sp->size;
+      flag_t flag = sp->sflags;
+      sp = sp->next;
+      if ((flag & IS_MMAPPED_BIT) && !(flag & EXTERN_BIT) &&
+          CALL_MUNMAP(base, size) == 0)
+        freed += size;
+    }
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return freed;
+}
+
+/*
+  mspace versions of routines are near-clones of the global
+  versions. This is not so nice but better than the alternatives.
+*/
+
+
+void* mspace_malloc(mspace msp, size_t bytes) {
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  if (!PREACTION(ms)) {
+    void* mem;
+    size_t nb;
+    if (bytes <= MAX_SMALL_REQUEST) {
+      bindex_t idx;
+      binmap_t smallbits;
+      nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
+      idx = small_index(nb);
+      smallbits = ms->smallmap >> idx;
+
+      if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
+        mchunkptr b, p;
+        idx += ~smallbits & 1;       /* Uses next bin if idx empty */
+        b = smallbin_at(ms, idx);
+        p = b->fd;
+        assert(chunksize(p) == small_index2size(idx));
+        unlink_first_small_chunk(ms, b, p, idx);
+        set_inuse_and_pinuse(ms, p, small_index2size(idx));
+        mem = chunk2mem(p);
+        check_malloced_chunk(ms, mem, nb);
+        goto postaction;
+      }
+
+      else if (nb > ms->dvsize) {
+        if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
+          mchunkptr b, p, r;
+          size_t rsize;
+          bindex_t i;
+          binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
+          binmap_t leastbit = least_bit(leftbits);
+          compute_bit2idx(leastbit, i);
+          b = smallbin_at(ms, i);
+          p = b->fd;
+          assert(chunksize(p) == small_index2size(i));
+          unlink_first_small_chunk(ms, b, p, i);
+          rsize = small_index2size(i) - nb;
+          /* Fit here cannot be remainderless if 4byte sizes */
+          if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
+            set_inuse_and_pinuse(ms, p, small_index2size(i));
+          else {
+            set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
+            r = chunk_plus_offset(p, nb);
+            set_size_and_pinuse_of_free_chunk(r, rsize);
+            replace_dv(ms, r, rsize);
+          }
+          mem = chunk2mem(p);
+          check_malloced_chunk(ms, mem, nb);
+          goto postaction;
+        }
+
+        else if (ms->treemap != 0 && (mem = tmalloc_small(ms, nb)) != 0) {
+          check_malloced_chunk(ms, mem, nb);
+          goto postaction;
+        }
+      }
+    }
+    else if (bytes >= MAX_REQUEST)
+      nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
+    else {
+      nb = pad_request(bytes);
+      if (ms->treemap != 0 && (mem = tmalloc_large(ms, nb)) != 0) {
+        check_malloced_chunk(ms, mem, nb);
+        goto postaction;
+      }
+    }
+
+    if (nb <= ms->dvsize) {
+      size_t rsize = ms->dvsize - nb;
+      mchunkptr p = ms->dv;
+      if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
+        mchunkptr r = ms->dv = chunk_plus_offset(p, nb);
+        ms->dvsize = rsize;
+        set_size_and_pinuse_of_free_chunk(r, rsize);
+        set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
+      }
+      else { /* exhaust dv */
+        size_t dvs = ms->dvsize;
+        ms->dvsize = 0;
+        ms->dv = 0;
+        set_inuse_and_pinuse(ms, p, dvs);
+      }
+      mem = chunk2mem(p);
+      check_malloced_chunk(ms, mem, nb);
+      goto postaction;
+    }
+
+    else if (nb < ms->topsize) { /* Split top */
+      size_t rsize = ms->topsize -= nb;
+      mchunkptr p = ms->top;
+      mchunkptr r = ms->top = chunk_plus_offset(p, nb);
+      r->head = rsize | PINUSE_BIT;
+      set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
+      mem = chunk2mem(p);
+      check_top_chunk(ms, ms->top);
+      check_malloced_chunk(ms, mem, nb);
+      goto postaction;
+    }
+
+    mem = sys_alloc(ms, nb);
+
+  postaction:
+    POSTACTION(ms);
+    return mem;
+  }
+
+  return 0;
+}
+
+void mspace_free(mspace msp, void* mem) {
+  if (mem != 0) {
+    mchunkptr p  = mem2chunk(mem);
+#if FOOTERS
+    mstate fm = get_mstate_for(p);
+#else /* FOOTERS */
+    mstate fm = (mstate)msp;
+#endif /* FOOTERS */
+    if (!ok_magic(fm)) {
+      USAGE_ERROR_ACTION(fm, p);
+      return;
+    }
+    if (!PREACTION(fm)) {
+      check_inuse_chunk(fm, p);
+      if (RTCHECK(ok_address(fm, p) && ok_cinuse(p))) {
+        size_t psize = chunksize(p);
+        mchunkptr next = chunk_plus_offset(p, psize);
+        if (!pinuse(p)) {
+          size_t prevsize = p->prev_foot;
+          if ((prevsize & IS_MMAPPED_BIT) != 0) {
+            prevsize &= ~IS_MMAPPED_BIT;
+            psize += prevsize + MMAP_FOOT_PAD;
+            if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
+              fm->footprint -= psize;
+            goto postaction;
+          }
+          else {
+            mchunkptr prev = chunk_minus_offset(p, prevsize);
+            psize += prevsize;
+            p = prev;
+            if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
+              if (p != fm->dv) {
+                unlink_chunk(fm, p, prevsize);
+              }
+              else if ((next->head & INUSE_BITS) == INUSE_BITS) {
+                fm->dvsize = psize;
+                set_free_with_pinuse(p, psize, next);
+                goto postaction;
+              }
+            }
+            else
+              goto erroraction;
+          }
+        }
+
+        if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
+          if (!cinuse(next)) {  /* consolidate forward */
+            if (next == fm->top) {
+              size_t tsize = fm->topsize += psize;
+              fm->top = p;
+              p->head = tsize | PINUSE_BIT;
+              if (p == fm->dv) {
+                fm->dv = 0;
+                fm->dvsize = 0;
+              }
+              if (should_trim(fm, tsize))
+                sys_trim(fm, 0);
+              goto postaction;
+            }
+            else if (next == fm->dv) {
+              size_t dsize = fm->dvsize += psize;
+              fm->dv = p;
+              set_size_and_pinuse_of_free_chunk(p, dsize);
+              goto postaction;
+            }
+            else {
+              size_t nsize = chunksize(next);
+              psize += nsize;
+              unlink_chunk(fm, next, nsize);
+              set_size_and_pinuse_of_free_chunk(p, psize);
+              if (p == fm->dv) {
+                fm->dvsize = psize;
+                goto postaction;
+              }
+            }
+          }
+          else
+            set_free_with_pinuse(p, psize, next);
+          insert_chunk(fm, p, psize);
+          check_free_chunk(fm, p);
+          goto postaction;
+        }
+      }
+    erroraction:
+      USAGE_ERROR_ACTION(fm, p);
+    postaction:
+      POSTACTION(fm);
+    }
+  }
+}
+
+void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size) {
+  void *mem;
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  if (n_elements && MAX_SIZE_T / n_elements < elem_size) {
+    /* Fail on overflow */
+    MALLOC_FAILURE_ACTION;
+    return NULL;
+  }
+  elem_size *= n_elements;
+  mem = internal_malloc(ms, elem_size);
+  if (mem && calloc_must_clear(mem2chunk(mem)))
+    memset(mem, 0, elem_size);
+  return mem;
+}
+
+void* mspace_realloc(mspace msp, void* oldmem, size_t bytes) {
+  if (oldmem == 0)
+    return mspace_malloc(msp, bytes);
+#ifdef REALLOC_ZERO_BYTES_FREES
+  if (bytes == 0) {
+    mspace_free(msp, oldmem);
+    return 0;
+  }
+#endif /* REALLOC_ZERO_BYTES_FREES */
+  else {
+#if FOOTERS
+    mchunkptr p  = mem2chunk(oldmem);
+    mstate ms = get_mstate_for(p);
+#else /* FOOTERS */
+    mstate ms = (mstate)msp;
+#endif /* FOOTERS */
+    if (!ok_magic(ms)) {
+      USAGE_ERROR_ACTION(ms,ms);
+      return 0;
+    }
+    return internal_realloc(ms, oldmem, bytes);
+  }
+}
+
+#if ANDROID
+void* mspace_merge_objects(mspace msp, void* mema, void* memb)
+{
+  /* PREACTION/POSTACTION aren't necessary because we are only
+     modifying fields of inuse chunks owned by the current thread, in
+     which case no other malloc operations can touch them.
+   */
+  if (mema == NULL || memb == NULL) {
+    return NULL;
+  }
+  mchunkptr pa = mem2chunk(mema);
+  mchunkptr pb = mem2chunk(memb);
+
+#if FOOTERS
+  mstate fm = get_mstate_for(pa);
+#else /* FOOTERS */
+  mstate fm = (mstate)msp;
+#endif /* FOOTERS */
+  if (!ok_magic(fm)) {
+    USAGE_ERROR_ACTION(fm, pa);
+    return NULL;
+  }
+  check_inuse_chunk(fm, pa);
+  if (RTCHECK(ok_address(fm, pa) && ok_cinuse(pa))) {
+    if (next_chunk(pa) != pb) {
+      /* Since pb may not be in fm, we can't check ok_address(fm, pb);
+         since ok_cinuse(pb) would be unsafe before an address check,
+         return NULL rather than invoke USAGE_ERROR_ACTION if pb is not
+         in use or is a bogus address.
+       */
+      return NULL;
+    }
+    /* Since b follows a, they share the mspace. */
+#if FOOTERS
+    assert(fm == get_mstate_for(pb));
+#endif /* FOOTERS */
+    check_inuse_chunk(fm, pb);
+    if (RTCHECK(ok_address(fm, pb) && ok_cinuse(pb))) {
+      size_t sz = chunksize(pb);
+      pa->head += sz;
+      /* Make sure pa still passes. */
+      check_inuse_chunk(fm, pa);
+      return mema;
+    }
+    else {
+      USAGE_ERROR_ACTION(fm, pb);
+      return NULL;
+    }
+  }
+  else {
+    USAGE_ERROR_ACTION(fm, pa);
+    return NULL;
+  }
+}
+#endif /* ANDROID */
+
+void* mspace_memalign(mspace msp, size_t alignment, size_t bytes) {
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  return internal_memalign(ms, alignment, bytes);
+}
+
+void** mspace_independent_calloc(mspace msp, size_t n_elements,
+                                 size_t elem_size, void* chunks[]) {
+  size_t sz = elem_size; /* serves as 1-element array */
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  return ialloc(ms, n_elements, &sz, 3, chunks);
+}
+
+void** mspace_independent_comalloc(mspace msp, size_t n_elements,
+                                   size_t sizes[], void* chunks[]) {
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  return ialloc(ms, n_elements, sizes, 0, chunks);
+}
+
+int mspace_trim(mspace msp, size_t pad) {
+  int result = 0;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    if (!PREACTION(ms)) {
+      result = sys_trim(ms, pad);
+      POSTACTION(ms);
+    }
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return result;
+}
+
+void mspace_malloc_stats(mspace msp) {
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    internal_malloc_stats(ms);
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+}
+
+size_t mspace_footprint(mspace msp) {
+  size_t result;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    result = ms->footprint;
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return result;
+}
+
+#if USE_MAX_ALLOWED_FOOTPRINT
+size_t mspace_max_allowed_footprint(mspace msp) {
+  size_t result;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    result = ms->max_allowed_footprint;
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return result;
+}
+
+void mspace_set_max_allowed_footprint(mspace msp, size_t bytes) {
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    if (bytes > ms->footprint) {
+      /* Increase the size in multiples of the granularity,
+       * which is the smallest unit we request from the system.
+       */
+      ms->max_allowed_footprint = ms->footprint +
+                                  granularity_align(bytes - ms->footprint);
+    }
+    else {
+      //TODO: allow for reducing the max footprint
+      ms->max_allowed_footprint = ms->footprint;
+    }
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+}
+#endif
+
+size_t mspace_max_footprint(mspace msp) {
+  size_t result;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    result = ms->max_footprint;
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return result;
+}
+
+
+#if !NO_MALLINFO
+struct mallinfo mspace_mallinfo(mspace msp) {
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return internal_mallinfo(ms);
+}
+#endif /* NO_MALLINFO */
+
+int mspace_mallopt(int param_number, int value) {
+  return change_mparam(param_number, value);
+}
+
+#endif /* MSPACES */
+
+#if MSPACES && ONLY_MSPACES
+void mspace_walk_free_pages(mspace msp,
+    void(*handler)(void *start, void *end, void *arg), void *harg)
+{
+  mstate m = (mstate)msp;
+  if (!ok_magic(m)) {
+    USAGE_ERROR_ACTION(m,m);
+    return;
+  }
+#else
+void dlmalloc_walk_free_pages(void(*handler)(void *start, void *end, void *arg),
+    void *harg)
+{
+  mstate m = (mstate)gm;
+#endif
+  if (!PREACTION(m)) {
+    if (is_initialized(m)) {
+      msegmentptr s = &m->seg;
+      while (s != 0) {
+        mchunkptr p = align_as_chunk(s->base);
+        while (segment_holds(s, p) &&
+               p != m->top && p->head != FENCEPOST_HEAD) {
+          void *chunkptr;
+          size_t chunklen;
+          chunkptr = p;
+          chunklen = chunksize(p);
+          if (!cinuse(p)) {
+            void *start;
+            if (is_small(chunklen)) {
+              start = (void *)(p + 1);
+            }
+            else {
+              start = (void *)((tchunkptr)p + 1);
+            }
+            handler(start, next_chunk(p), harg);
+          }
+          p = next_chunk(p);
+        }
+        if (p == m->top) {
+          handler((void *)(p + 1), next_chunk(p), harg);
+        }
+        s = s->next;
+      }
+    }
+    POSTACTION(m);
+  }
+}
+
+
+#if MSPACES && ONLY_MSPACES
+void mspace_walk_heap(mspace msp,
+                      void(*handler)(const void *chunkptr, size_t chunklen,
+                                     const void *userptr, size_t userlen,
+                                     void *arg),
+                      void *harg)
+{
+  msegmentptr s;
+  mstate m = (mstate)msp;
+  if (!ok_magic(m)) {
+    USAGE_ERROR_ACTION(m,m);
+    return;
+  }
+#else
+void dlmalloc_walk_heap(void(*handler)(const void *chunkptr, size_t chunklen,
+                                       const void *userptr, size_t userlen,
+                                       void *arg),
+                        void *harg)
+{
+  msegmentptr s;
+  mstate m = (mstate)gm;
+#endif
+
+  s = &m->seg;
+  while (s != 0) {
+    mchunkptr p = align_as_chunk(s->base);
+    while (segment_holds(s, p) &&
+           p != m->top && p->head != FENCEPOST_HEAD) {
+      void *chunkptr, *userptr;
+      size_t chunklen, userlen;
+      chunkptr = p;
+      chunklen = chunksize(p);
+      if (cinuse(p)) {
+        userptr = chunk2mem(p);
+        userlen = chunklen - overhead_for(p);
+      }
+      else {
+        userptr = NULL;
+        userlen = 0;
+      }
+      handler(chunkptr, chunklen, userptr, userlen, harg);
+      p = next_chunk(p);
+    }
+    if (p == m->top) {
+      /* The top chunk is just a big free chunk for our purposes.
+       */
+      handler(m->top, m->topsize, NULL, 0, harg);
+    }
+    s = s->next;
+  }
+}
+
+/* -------------------- Alternative MORECORE functions ------------------- */
+
+/*
+  Guidelines for creating a custom version of MORECORE:
+
+  * For best performance, MORECORE should allocate in multiples of pagesize.
+  * MORECORE may allocate more memory than requested. (Or even less,
+      but this will usually result in a malloc failure.)
+  * MORECORE must not allocate memory when given argument zero, but
+      instead return one past the end address of memory from previous
+      nonzero call.
+  * For best performance, consecutive calls to MORECORE with positive
+      arguments should return increasing addresses, indicating that
+      space has been contiguously extended.
+  * Even though consecutive calls to MORECORE need not return contiguous
+      addresses, it must be OK for malloc'ed chunks to span multiple
+      regions in those cases where they do happen to be contiguous.
+  * MORECORE need not handle negative arguments -- it may instead
+      just return MFAIL when given negative arguments.
+      Negative arguments are always multiples of pagesize. MORECORE
+      must not misinterpret negative args as large positive unsigned
+      args. You can suppress all such calls from even occurring by defining
+      MORECORE_CANNOT_TRIM,
+
+  As an example alternative MORECORE, here is a custom allocator
+  kindly contributed for pre-OSX macOS.  It uses virtually but not
+  necessarily physically contiguous non-paged memory (locked in,
+  present and won't get swapped out).  You can use it by uncommenting
+  this section, adding some #includes, and setting up the appropriate
+  defines above:
+
+      #define MORECORE osMoreCore
+
+  There is also a shutdown routine that should somehow be called for
+  cleanup upon program exit.
+
+  #define MAX_POOL_ENTRIES 100
+  #define MINIMUM_MORECORE_SIZE  (64 * 1024U)
+  static int next_os_pool;
+  void *our_os_pools[MAX_POOL_ENTRIES];
+
+  void *osMoreCore(int size)
+  {
+    void *ptr = 0;
+    static void *sbrk_top = 0;
+
+    if (size > 0)
+    {
+      if (size < MINIMUM_MORECORE_SIZE)
+         size = MINIMUM_MORECORE_SIZE;
+      if (CurrentExecutionLevel() == kTaskLevel)
+         ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
+      if (ptr == 0)
+      {
+        return (void *) MFAIL;
+      }
+      // save ptrs so they can be freed during cleanup
+      our_os_pools[next_os_pool] = ptr;
+      next_os_pool++;
+      ptr = (void *) ((((size_t) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
+      sbrk_top = (char *) ptr + size;
+      return ptr;
+    }
+    else if (size < 0)
+    {
+      // we don't currently support shrink behavior
+      return (void *) MFAIL;
+    }
+    else
+    {
+      return sbrk_top;
+    }
+  }
+
+  // cleanup any allocated memory pools
+  // called as last thing before shutting down driver
+
+  void osCleanupMem(void)
+  {
+    void **ptr;
+
+    for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
+      if (*ptr)
+      {
+         PoolDeallocate(*ptr);
+         *ptr = 0;
+      }
+  }
+
+*/
+
+
+/* -----------------------------------------------------------------------
+History:
+    V2.8.3 Thu Sep 22 11:16:32 2005  Doug Lea  (dl at gee)
+      * Add max_footprint functions
+      * Ensure all appropriate literals are size_t
+      * Fix conditional compilation problem for some #define settings
+      * Avoid concatenating segments with the one provided
+        in create_mspace_with_base
+      * Rename some variables to avoid compiler shadowing warnings
+      * Use explicit lock initialization.
+      * Better handling of sbrk interference.
+      * Simplify and fix segment insertion, trimming and mspace_destroy
+      * Reinstate REALLOC_ZERO_BYTES_FREES option from 2.7.x
+      * Thanks especially to Dennis Flanagan for help on these.
+
+    V2.8.2 Sun Jun 12 16:01:10 2005  Doug Lea  (dl at gee)
+      * Fix memalign brace error.
+
+    V2.8.1 Wed Jun  8 16:11:46 2005  Doug Lea  (dl at gee)
+      * Fix improper #endif nesting in C++
+      * Add explicit casts needed for C++
+
+    V2.8.0 Mon May 30 14:09:02 2005  Doug Lea  (dl at gee)
+      * Use trees for large bins
+      * Support mspaces
+      * Use segments to unify sbrk-based and mmap-based system allocation,
+        removing need for emulation on most platforms without sbrk.
+      * Default safety checks
+      * Optional footer checks. Thanks to William Robertson for the idea.
+      * Internal code refactoring
+      * Incorporate suggestions and platform-specific changes.
+        Thanks to Dennis Flanagan, Colin Plumb, Niall Douglas,
+        Aaron Bachmann,  Emery Berger, and others.
+      * Speed up non-fastbin processing enough to remove fastbins.
+      * Remove useless cfree() to avoid conflicts with other apps.
+      * Remove internal memcpy, memset. Compilers handle builtins better.
+      * Remove some options that no one ever used and rename others.
+
+    V2.7.2 Sat Aug 17 09:07:30 2002  Doug Lea  (dl at gee)
+      * Fix malloc_state bitmap array misdeclaration
+
+    V2.7.1 Thu Jul 25 10:58:03 2002  Doug Lea  (dl at gee)
+      * Allow tuning of FIRST_SORTED_BIN_SIZE
+      * Use PTR_UINT as type for all ptr->int casts. Thanks to John Belmonte.
+      * Better detection and support for non-contiguousness of MORECORE.
+        Thanks to Andreas Mueller, Conal Walsh, and Wolfram Gloger
+      * Bypass most of malloc if no frees. Thanks To Emery Berger.
+      * Fix freeing of old top non-contiguous chunk im sysmalloc.
+      * Raised default trim and map thresholds to 256K.
+      * Fix mmap-related #defines. Thanks to Lubos Lunak.
+      * Fix copy macros; added LACKS_FCNTL_H. Thanks to Neal Walfield.
+      * Branch-free bin calculation
+      * Default trim and mmap thresholds now 256K.
+
+    V2.7.0 Sun Mar 11 14:14:06 2001  Doug Lea  (dl at gee)
+      * Introduce independent_comalloc and independent_calloc.
+        Thanks to Michael Pachos for motivation and help.
+      * Make optional .h file available
+      * Allow > 2GB requests on 32bit systems.
+      * new WIN32 sbrk, mmap, munmap, lock code from <Walter@GeNeSys-e.de>.
+        Thanks also to Andreas Mueller <a.mueller at paradatec.de>,
+        and Anonymous.
+      * Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for
+        helping test this.)
+      * memalign: check alignment arg
+      * realloc: don't try to shift chunks backwards, since this
+        leads to  more fragmentation in some programs and doesn't
+        seem to help in any others.
+      * Collect all cases in malloc requiring system memory into sysmalloc
+      * Use mmap as backup to sbrk
+      * Place all internal state in malloc_state
+      * Introduce fastbins (although similar to 2.5.1)
+      * Many minor tunings and cosmetic improvements
+      * Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK
+      * Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS
+        Thanks to Tony E. Bennett <tbennett@nvidia.com> and others.
+      * Include errno.h to support default failure action.
+
+    V2.6.6 Sun Dec  5 07:42:19 1999  Doug Lea  (dl at gee)
+      * return null for negative arguments
+      * Added Several WIN32 cleanups from Martin C. Fong <mcfong at yahoo.com>
+         * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
+          (e.g. WIN32 platforms)
+         * Cleanup header file inclusion for WIN32 platforms
+         * Cleanup code to avoid Microsoft Visual C++ compiler complaints
+         * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
+           memory allocation routines
+         * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
+         * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
+           usage of 'assert' in non-WIN32 code
+         * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
+           avoid infinite loop
+      * Always call 'fREe()' rather than 'free()'
+
+    V2.6.5 Wed Jun 17 15:57:31 1998  Doug Lea  (dl at gee)
+      * Fixed ordering problem with boundary-stamping
+
+    V2.6.3 Sun May 19 08:17:58 1996  Doug Lea  (dl at gee)
+      * Added pvalloc, as recommended by H.J. Liu
+      * Added 64bit pointer support mainly from Wolfram Gloger
+      * Added anonymously donated WIN32 sbrk emulation
+      * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
+      * malloc_extend_top: fix mask error that caused wastage after
+        foreign sbrks
+      * Add linux mremap support code from HJ Liu
+
+    V2.6.2 Tue Dec  5 06:52:55 1995  Doug Lea  (dl at gee)
+      * Integrated most documentation with the code.
+      * Add support for mmap, with help from
+        Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
+      * Use last_remainder in more cases.
+      * Pack bins using idea from  colin@nyx10.cs.du.edu
+      * Use ordered bins instead of best-fit threshhold
+      * Eliminate block-local decls to simplify tracing and debugging.
+      * Support another case of realloc via move into top
+      * Fix error occuring when initial sbrk_base not word-aligned.
+      * Rely on page size for units instead of SBRK_UNIT to
+        avoid surprises about sbrk alignment conventions.
+      * Add mallinfo, mallopt. Thanks to Raymond Nijssen
+        (raymond@es.ele.tue.nl) for the suggestion.
+      * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
+      * More precautions for cases where other routines call sbrk,
+        courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
+      * Added macros etc., allowing use in linux libc from
+        H.J. Lu (hjl@gnu.ai.mit.edu)
+      * Inverted this history list
+
+    V2.6.1 Sat Dec  2 14:10:57 1995  Doug Lea  (dl at gee)
+      * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
+      * Removed all preallocation code since under current scheme
+        the work required to undo bad preallocations exceeds
+        the work saved in good cases for most test programs.
+      * No longer use return list or unconsolidated bins since
+        no scheme using them consistently outperforms those that don't
+        given above changes.
+      * Use best fit for very large chunks to prevent some worst-cases.
+      * Added some support for debugging
+
+    V2.6.0 Sat Nov  4 07:05:23 1995  Doug Lea  (dl at gee)
+      * Removed footers when chunks are in use. Thanks to
+        Paul Wilson (wilson@cs.texas.edu) for the suggestion.
+
+    V2.5.4 Wed Nov  1 07:54:51 1995  Doug Lea  (dl at gee)
+      * Added malloc_trim, with help from Wolfram Gloger
+        (wmglo@Dent.MED.Uni-Muenchen.DE).
+
+    V2.5.3 Tue Apr 26 10:16:01 1994  Doug Lea  (dl at g)
+
+    V2.5.2 Tue Apr  5 16:20:40 1994  Doug Lea  (dl at g)
+      * realloc: try to expand in both directions
+      * malloc: swap order of clean-bin strategy;
+      * realloc: only conditionally expand backwards
+      * Try not to scavenge used bins
+      * Use bin counts as a guide to preallocation
+      * Occasionally bin return list chunks in first scan
+      * Add a few optimizations from colin@nyx10.cs.du.edu
+
+    V2.5.1 Sat Aug 14 15:40:43 1993  Doug Lea  (dl at g)
+      * faster bin computation & slightly different binning
+      * merged all consolidations to one part of malloc proper
+         (eliminating old malloc_find_space & malloc_clean_bin)
+      * Scan 2 returns chunks (not just 1)
+      * Propagate failure in realloc if malloc returns 0
+      * Add stuff to allow compilation on non-ANSI compilers
+          from kpv@research.att.com
+
+    V2.5 Sat Aug  7 07:41:59 1993  Doug Lea  (dl at g.oswego.edu)
+      * removed potential for odd address access in prev_chunk
+      * removed dependency on getpagesize.h
+      * misc cosmetics and a bit more internal documentation
+      * anticosmetics: mangled names in macros to evade debugger strangeness
+      * tested on sparc, hp-700, dec-mips, rs6000
+          with gcc & native cc (hp, dec only) allowing
+          Detlefs & Zorn comparison study (in SIGPLAN Notices.)
+
+    Trial version Fri Aug 28 13:14:29 1992  Doug Lea  (dl at g.oswego.edu)
+      * Based loosely on libg++-1.2X malloc. (It retains some of the overall
+         structure of old version,  but most details differ.)
+
+*/
diff --git a/src/dlmalloc.h b/src/dlmalloc.h
new file mode 100644
index 0000000..1b642d2
--- /dev/null
+++ b/src/dlmalloc.h
@@ -0,0 +1,655 @@
+/*
+  Default header file for malloc-2.8.x, written by Doug Lea
+  and released to the public domain, as explained at
+  http://creativecommons.org/licenses/publicdomain.
+
+  last update: Mon Aug 15 08:55:52 2005  Doug Lea  (dl at gee)
+
+  This header is for ANSI C/C++ only.  You can set any of
+  the following #defines before including:
+
+  * If USE_DL_PREFIX is defined, it is assumed that malloc.c
+    was also compiled with this option, so all routines
+    have names starting with "dl".
+
+  * If HAVE_USR_INCLUDE_MALLOC_H is defined, it is assumed that this
+    file will be #included AFTER <malloc.h>. This is needed only if
+    your system defines a struct mallinfo that is incompatible with the
+    standard one declared here.  Otherwise, you can include this file
+    INSTEAD of your system system <malloc.h>.  At least on ANSI, all
+    declarations should be compatible with system versions
+
+  * If MSPACES is defined, declarations for mspace versions are included.
+*/
+
+#ifndef MALLOC_280_H
+#define MALLOC_280_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>   /* for size_t */
+
+#if !ONLY_MSPACES
+
+/* Check an additional macro for the five primary functions */
+#if !defined(USE_DL_PREFIX)
+#define dlcalloc               calloc
+#define dlfree                 free
+#define dlmalloc               malloc
+#define dlmemalign             memalign
+#define dlrealloc              realloc
+#endif
+
+#ifndef USE_DL_PREFIX
+#define dlvalloc               valloc
+#define dlpvalloc              pvalloc
+#define dlmallinfo             mallinfo
+#define dlmallopt              mallopt
+#define dlmalloc_trim          malloc_trim
+#define dlmalloc_walk_free_pages \
+                               malloc_walk_free_pages
+#define dlmalloc_walk_heap \
+                               malloc_walk_heap
+#define dlmalloc_stats         malloc_stats
+#define dlmalloc_usable_size   malloc_usable_size
+#define dlmalloc_footprint     malloc_footprint
+#define dlmalloc_max_allowed_footprint \
+                               malloc_max_allowed_footprint
+#define dlmalloc_set_max_allowed_footprint \
+                               malloc_set_max_allowed_footprint
+#define dlmalloc_max_footprint malloc_max_footprint
+#define dlindependent_calloc   independent_calloc
+#define dlindependent_comalloc independent_comalloc
+#endif /* USE_DL_PREFIX */
+
+
+/*
+  malloc(size_t n)
+  Returns a pointer to a newly allocated chunk of at least n bytes, or
+  null if no space is available, in which case errno is set to ENOMEM
+  on ANSI C systems.
+
+  If n is zero, malloc returns a minimum-sized chunk. (The minimum
+  size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
+  systems.)  Note that size_t is an unsigned type, so calls with
+  arguments that would be negative if signed are interpreted as
+  requests for huge amounts of space, which will often fail. The
+  maximum supported value of n differs across systems, but is in all
+  cases less than the maximum representable value of a size_t.
+*/
+void* dlmalloc(size_t);
+
+/*
+  free(void* p)
+  Releases the chunk of memory pointed to by p, that had been previously
+  allocated using malloc or a related routine such as realloc.
+  It has no effect if p is null. If p was not malloced or already
+  freed, free(p) will by default cuase the current program to abort.
+*/
+void  dlfree(void*);
+
+/*
+  calloc(size_t n_elements, size_t element_size);
+  Returns a pointer to n_elements * element_size bytes, with all locations
+  set to zero.
+*/
+void* dlcalloc(size_t, size_t);
+
+/*
+  realloc(void* p, size_t n)
+  Returns a pointer to a chunk of size n that contains the same data
+  as does chunk p up to the minimum of (n, p's size) bytes, or null
+  if no space is available.
+
+  The returned pointer may or may not be the same as p. The algorithm
+  prefers extending p in most cases when possible, otherwise it
+  employs the equivalent of a malloc-copy-free sequence.
+
+  If p is null, realloc is equivalent to malloc.
+
+  If space is not available, realloc returns null, errno is set (if on
+  ANSI) and p is NOT freed.
+
+  if n is for fewer bytes than already held by p, the newly unused
+  space is lopped off and freed if possible.  realloc with a size
+  argument of zero (re)allocates a minimum-sized chunk.
+
+  The old unix realloc convention of allowing the last-free'd chunk
+  to be used as an argument to realloc is not supported.
+*/
+
+void* dlrealloc(void*, size_t);
+
+/*
+  memalign(size_t alignment, size_t n);
+  Returns a pointer to a newly allocated chunk of n bytes, aligned
+  in accord with the alignment argument.
+
+  The alignment argument should be a power of two. If the argument is
+  not a power of two, the nearest greater power is used.
+  8-byte alignment is guaranteed by normal malloc calls, so don't
+  bother calling memalign with an argument of 8 or less.
+
+  Overreliance on memalign is a sure way to fragment space.
+*/
+void* dlmemalign(size_t, size_t);
+
+/*
+  valloc(size_t n);
+  Equivalent to memalign(pagesize, n), where pagesize is the page
+  size of the system. If the pagesize is unknown, 4096 is used.
+*/
+void* dlvalloc(size_t);
+
+/*
+  mallopt(int parameter_number, int parameter_value)
+  Sets tunable parameters The format is to provide a
+  (parameter-number, parameter-value) pair.  mallopt then sets the
+  corresponding parameter to the argument value if it can (i.e., so
+  long as the value is meaningful), and returns 1 if successful else
+  0.  SVID/XPG/ANSI defines four standard param numbers for mallopt,
+  normally defined in malloc.h.  None of these are use in this malloc,
+  so setting them has no effect. But this malloc also supports other
+  options in mallopt:
+
+  Symbol            param #  default    allowed param values
+  M_TRIM_THRESHOLD     -1   2*1024*1024   any   (-1U disables trimming)
+  M_GRANULARITY        -2     page size   any power of 2 >= page size
+  M_MMAP_THRESHOLD     -3      256*1024   any   (or 0 if no MMAP support)
+*/
+int dlmallopt(int, int);
+
+#define M_TRIM_THRESHOLD     (-1)
+#define M_GRANULARITY        (-2)
+#define M_MMAP_THRESHOLD     (-3)
+
+
+/*
+  malloc_footprint();
+  Returns the number of bytes obtained from the system.  The total
+  number of bytes allocated by malloc, realloc etc., is less than this
+  value. Unlike mallinfo, this function returns only a precomputed
+  result, so can be called frequently to monitor memory consumption.
+  Even if locks are otherwise defined, this function does not use them,
+  so results might not be up to date.
+*/
+size_t dlmalloc_footprint();
+
+/*
+  malloc_max_allowed_footprint();
+  Returns the number of bytes that the heap is allowed to obtain
+  from the system.  malloc_footprint() should always return a
+  size less than or equal to max_allowed_footprint, unless the
+  max_allowed_footprint was set to a value smaller than the
+  footprint at the time.
+
+  This function is only available if dlmalloc.c was compiled
+  with USE_MAX_ALLOWED_FOOTPRINT set.
+*/
+size_t dlmalloc_max_allowed_footprint();
+
+/*
+  malloc_set_max_allowed_footprint();
+  Set the maximum number of bytes that the heap is allowed to
+  obtain from the system.  The size will be rounded up to a whole
+  page, and the rounded number will be returned from future calls
+  to malloc_max_allowed_footprint().  If the new max_allowed_footprint
+  is larger than the current footprint, the heap will never grow
+  larger than max_allowed_footprint.  If the new max_allowed_footprint
+  is smaller than the current footprint, the heap will not grow
+  further.
+
+  This function is only available if dlmalloc.c was compiled
+  with USE_MAX_ALLOWED_FOOTPRINT set.
+
+  TODO: try to force the heap to give up memory in the shrink case,
+        and update this comment once that happens.
+*/
+void dlmalloc_set_max_allowed_footprint(size_t bytes);
+
+/*
+  malloc_max_footprint();
+  Returns the maximum number of bytes obtained from the system. This
+  value will be greater than current footprint if deallocated space
+  has been reclaimed by the system. The peak number of bytes allocated
+  by malloc, realloc etc., is less than this value. Unlike mallinfo,
+  this function returns only a precomputed result, so can be called
+  frequently to monitor memory consumption.  Even if locks are
+  otherwise defined, this function does not use them, so results might
+  not be up to date.
+*/
+size_t dlmalloc_max_footprint(void);
+
+#if !NO_MALLINFO
+/*
+  mallinfo()
+  Returns (by copy) a struct containing various summary statistics:
+
+  arena:     current total non-mmapped bytes allocated from system
+  ordblks:   the number of free chunks
+  smblks:    always zero.
+  hblks:     current number of mmapped regions
+  hblkhd:    total bytes held in mmapped regions
+  usmblks:   the maximum total allocated space. This will be greater
+                than current total if trimming has occurred.
+  fsmblks:   always zero
+  uordblks:  current total allocated space (normal or mmapped)
+  fordblks:  total free space
+  keepcost:  the maximum number of bytes that could ideally be released
+               back to system via malloc_trim. ("ideally" means that
+               it ignores page restrictions etc.)
+
+  Because these fields are ints, but internal bookkeeping may
+  be kept as longs, the reported values may wrap around zero and
+  thus be inaccurate.
+*/
+#ifndef HAVE_USR_INCLUDE_MALLOC_H
+#ifndef _MALLOC_H_
+#ifndef MALLINFO_FIELD_TYPE
+#define MALLINFO_FIELD_TYPE size_t
+#endif /* MALLINFO_FIELD_TYPE */
+struct mallinfo {
+  MALLINFO_FIELD_TYPE arena;    /* non-mmapped space allocated from system */
+  MALLINFO_FIELD_TYPE ordblks;  /* number of free chunks */
+  MALLINFO_FIELD_TYPE smblks;   /* always 0 */
+  MALLINFO_FIELD_TYPE hblks;    /* always 0 */
+  MALLINFO_FIELD_TYPE hblkhd;   /* space in mmapped regions */
+  MALLINFO_FIELD_TYPE usmblks;  /* maximum total allocated space */
+  MALLINFO_FIELD_TYPE fsmblks;  /* always 0 */
+  MALLINFO_FIELD_TYPE uordblks; /* total allocated space */
+  MALLINFO_FIELD_TYPE fordblks; /* total free space */
+  MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */
+};
+#endif  /* _MALLOC_H_ */
+#endif  /* HAVE_USR_INCLUDE_MALLOC_H */
+
+struct mallinfo dlmallinfo(void);
+#endif  /* NO_MALLINFO */
+
+/*
+  independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
+
+  independent_calloc is similar to calloc, but instead of returning a
+  single cleared space, it returns an array of pointers to n_elements
+  independent elements that can hold contents of size elem_size, each
+  of which starts out cleared, and can be independently freed,
+  realloc'ed etc. The elements are guaranteed to be adjacently
+  allocated (this is not guaranteed to occur with multiple callocs or
+  mallocs), which may also improve cache locality in some
+  applications.
+
+  The "chunks" argument is optional (i.e., may be null, which is
+  probably the most typical usage). If it is null, the returned array
+  is itself dynamically allocated and should also be freed when it is
+  no longer needed. Otherwise, the chunks array must be of at least
+  n_elements in length. It is filled in with the pointers to the
+  chunks.
+
+  In either case, independent_calloc returns this pointer array, or
+  null if the allocation failed.  If n_elements is zero and "chunks"
+  is null, it returns a chunk representing an array with zero elements
+  (which should be freed if not wanted).
+
+  Each element must be individually freed when it is no longer
+  needed. If you'd like to instead be able to free all at once, you
+  should instead use regular calloc and assign pointers into this
+  space to represent elements.  (In this case though, you cannot
+  independently free elements.)
+
+  independent_calloc simplifies and speeds up implementations of many
+  kinds of pools.  It may also be useful when constructing large data
+  structures that initially have a fixed number of fixed-sized nodes,
+  but the number is not known at compile time, and some of the nodes
+  may later need to be freed. For example:
+
+  struct Node { int item; struct Node* next; };
+
+  struct Node* build_list() {
+    struct Node** pool;
+    int n = read_number_of_nodes_needed();
+    if (n <= 0) return 0;
+    pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
+    if (pool == 0) die();
+    // organize into a linked list...
+    struct Node* first = pool[0];
+    for (i = 0; i < n-1; ++i)
+      pool[i]->next = pool[i+1];
+    free(pool);     // Can now free the array (or not, if it is needed later)
+    return first;
+  }
+*/
+void** dlindependent_calloc(size_t, size_t, void**);
+
+/*
+  independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
+
+  independent_comalloc allocates, all at once, a set of n_elements
+  chunks with sizes indicated in the "sizes" array.    It returns
+  an array of pointers to these elements, each of which can be
+  independently freed, realloc'ed etc. The elements are guaranteed to
+  be adjacently allocated (this is not guaranteed to occur with
+  multiple callocs or mallocs), which may also improve cache locality
+  in some applications.
+
+  The "chunks" argument is optional (i.e., may be null). If it is null
+  the returned array is itself dynamically allocated and should also
+  be freed when it is no longer needed. Otherwise, the chunks array
+  must be of at least n_elements in length. It is filled in with the
+  pointers to the chunks.
+
+  In either case, independent_comalloc returns this pointer array, or
+  null if the allocation failed.  If n_elements is zero and chunks is
+  null, it returns a chunk representing an array with zero elements
+  (which should be freed if not wanted).
+
+  Each element must be individually freed when it is no longer
+  needed. If you'd like to instead be able to free all at once, you
+  should instead use a single regular malloc, and assign pointers at
+  particular offsets in the aggregate space. (In this case though, you
+  cannot independently free elements.)
+
+  independent_comallac differs from independent_calloc in that each
+  element may have a different size, and also that it does not
+  automatically clear elements.
+
+  independent_comalloc can be used to speed up allocation in cases
+  where several structs or objects must always be allocated at the
+  same time.  For example:
+
+  struct Head { ... }
+  struct Foot { ... }
+
+  void send_message(char* msg) {
+    int msglen = strlen(msg);
+    size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
+    void* chunks[3];
+    if (independent_comalloc(3, sizes, chunks) == 0)
+      die();
+    struct Head* head = (struct Head*)(chunks[0]);
+    char*        body = (char*)(chunks[1]);
+    struct Foot* foot = (struct Foot*)(chunks[2]);
+    // ...
+  }
+
+  In general though, independent_comalloc is worth using only for
+  larger values of n_elements. For small values, you probably won't
+  detect enough difference from series of malloc calls to bother.
+
+  Overuse of independent_comalloc can increase overall memory usage,
+  since it cannot reuse existing noncontiguous small chunks that
+  might be available for some of the elements.
+*/
+void** dlindependent_comalloc(size_t, size_t*, void**);
+
+
+/*
+  pvalloc(size_t n);
+  Equivalent to valloc(minimum-page-that-holds(n)), that is,
+  round up n to nearest pagesize.
+ */
+void*  dlpvalloc(size_t);
+
+/*
+  malloc_trim(size_t pad);
+
+  If possible, gives memory back to the system (via negative arguments
+  to sbrk) if there is unused memory at the `high' end of the malloc
+  pool or in unused MMAP segments. You can call this after freeing
+  large blocks of memory to potentially reduce the system-level memory
+  requirements of a program. However, it cannot guarantee to reduce
+  memory. Under some allocation patterns, some large free blocks of
+  memory will be locked between two used chunks, so they cannot be
+  given back to the system.
+
+  The `pad' argument to malloc_trim represents the amount of free
+  trailing space to leave untrimmed. If this argument is zero, only
+  the minimum amount of memory to maintain internal data structures
+  will be left. Non-zero arguments can be supplied to maintain enough
+  trailing space to service future expected allocations without having
+  to re-obtain memory from the system.
+
+  Malloc_trim returns 1 if it actually released any memory, else 0.
+*/
+int  dlmalloc_trim(size_t);
+
+/*
+  malloc_walk_free_pages(handler, harg)
+
+  Calls the provided handler on each free region in the heap.  The
+  memory between start and end are guaranteed not to contain any
+  important data, so the handler is free to alter the contents
+  in any way.  This can be used to advise the OS that large free
+  regions may be swapped out.
+
+  The value in harg will be passed to each call of the handler.
+ */
+void dlmalloc_walk_free_pages(void(*handler)(void *start, void *end, void *arg),
+    void *harg);
+
+/*
+  malloc_walk_heap(handler, harg)
+
+  Calls the provided handler on each object or free region in the
+  heap.  The handler will receive the chunk pointer and length, the
+  object pointer and length, and the value in harg on each call.
+ */
+void dlmalloc_walk_heap(void(*handler)(const void *chunkptr, size_t chunklen,
+                                       const void *userptr, size_t userlen,
+                                       void *arg),
+                        void *harg);
+
+/*
+  malloc_usable_size(void* p);
+
+  Returns the number of bytes you can actually use in
+  an allocated chunk, which may be more than you requested (although
+  often not) due to alignment and minimum size constraints.
+  You can use this many bytes without worrying about
+  overwriting other allocated objects. This is not a particularly great
+  programming practice. malloc_usable_size can be more useful in
+  debugging and assertions, for example:
+
+  p = malloc(n);
+  assert(malloc_usable_size(p) >= 256);
+*/
+size_t dlmalloc_usable_size(void*);
+
+/*
+  malloc_stats();
+  Prints on stderr the amount of space obtained from the system (both
+  via sbrk and mmap), the maximum amount (which may be more than
+  current if malloc_trim and/or munmap got called), and the current
+  number of bytes allocated via malloc (or realloc, etc) but not yet
+  freed. Note that this is the number of bytes allocated, not the
+  number requested. It will be larger than the number requested
+  because of alignment and bookkeeping overhead. Because it includes
+  alignment wastage as being in use, this figure may be greater than
+  zero even when no user-level chunks are allocated.
+
+  The reported current and maximum system memory can be inaccurate if
+  a program makes other calls to system memory allocation functions
+  (normally sbrk) outside of malloc.
+
+  malloc_stats prints only the most commonly interesting statistics.
+  More information can be obtained by calling mallinfo.
+*/
+void  dlmalloc_stats();
+
+#endif /* !ONLY_MSPACES */
+
+#if MSPACES
+
+/*
+  mspace is an opaque type representing an independent
+  region of space that supports mspace_malloc, etc.
+*/
+typedef void* mspace;
+
+/*
+  create_mspace creates and returns a new independent space with the
+  given initial capacity, or, if 0, the default granularity size.  It
+  returns null if there is no system memory available to create the
+  space.  If argument locked is non-zero, the space uses a separate
+  lock to control access. The capacity of the space will grow
+  dynamically as needed to service mspace_malloc requests.  You can
+  control the sizes of incremental increases of this space by
+  compiling with a different DEFAULT_GRANULARITY or dynamically
+  setting with mallopt(M_GRANULARITY, value).
+*/
+mspace create_mspace(size_t capacity, int locked);
+
+/*
+  destroy_mspace destroys the given space, and attempts to return all
+  of its memory back to the system, returning the total number of
+  bytes freed. After destruction, the results of access to all memory
+  used by the space become undefined.
+*/
+size_t destroy_mspace(mspace msp);
+
+/*
+  create_mspace_with_base uses the memory supplied as the initial base
+  of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
+  space is used for bookkeeping, so the capacity must be at least this
+  large. (Otherwise 0 is returned.) When this initial space is
+  exhausted, additional memory will be obtained from the system.
+  Destroying this space will deallocate all additionally allocated
+  space (if possible) but not the initial base.
+*/
+mspace create_mspace_with_base(void* base, size_t capacity, int locked);
+
+/*
+  mspace_malloc behaves as malloc, but operates within
+  the given space.
+*/
+void* mspace_malloc(mspace msp, size_t bytes);
+
+/*
+  mspace_free behaves as free, but operates within
+  the given space.
+
+  If compiled with FOOTERS==1, mspace_free is not actually needed.
+  free may be called instead of mspace_free because freed chunks from
+  any space are handled by their originating spaces.
+*/
+void mspace_free(mspace msp, void* mem);
+
+/*
+  mspace_realloc behaves as realloc, but operates within
+  the given space.
+
+  If compiled with FOOTERS==1, mspace_realloc is not actually
+  needed.  realloc may be called instead of mspace_realloc because
+  realloced chunks from any space are handled by their originating
+  spaces.
+*/
+void* mspace_realloc(mspace msp, void* mem, size_t newsize);
+
+/*
+  mspace_merge_objects will merge allocated memory mema and memb
+  together, provided memb immediately follows mema.  It is roughly as
+  if memb has been freed and mema has been realloced to a larger size.
+  On successfully merging, mema will be returned. If either argument
+  is null or memb does not immediately follow mema, null will be
+  returned.
+
+  Both mema and memb should have been previously allocated using
+  malloc or a related routine such as realloc. If either mema or memb
+  was not malloced or was previously freed, the result is undefined,
+  but like mspace_free, the default is to abort the program.
+*/
+void* mspace_merge_objects(mspace msp, void* mema, void* memb);
+
+/*
+  mspace_calloc behaves as calloc, but operates within
+  the given space.
+*/
+void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
+
+/*
+  mspace_memalign behaves as memalign, but operates within
+  the given space.
+*/
+void* mspace_memalign(mspace msp, size_t alignment, size_t bytes);
+
+/*
+  mspace_independent_calloc behaves as independent_calloc, but
+  operates within the given space.
+*/
+void** mspace_independent_calloc(mspace msp, size_t n_elements,
+                                 size_t elem_size, void* chunks[]);
+
+/*
+  mspace_independent_comalloc behaves as independent_comalloc, but
+  operates within the given space.
+*/
+void** mspace_independent_comalloc(mspace msp, size_t n_elements,
+                                   size_t sizes[], void* chunks[]);
+
+/*
+  mspace_footprint() returns the number of bytes obtained from the
+  system for this space.
+*/
+size_t mspace_footprint(mspace msp);
+
+/*
+  mspace_max_allowed_footprint() returns the number of bytes that
+  this space is allowed to obtain from the system. See
+  malloc_max_allowed_footprint() for a more in-depth description.
+
+  This function is only available if dlmalloc.c was compiled
+  with USE_MAX_ALLOWED_FOOTPRINT set.
+*/
+size_t mspace_max_allowed_footprint(mspace msp);
+
+/*
+  mspace_set_max_allowed_footprint() sets the maximum number of
+  bytes (rounded up to a page) that this space is allowed to
+  obtain from the system.  See malloc_set_max_allowed_footprint()
+  for a more in-depth description.
+
+  This function is only available if dlmalloc.c was compiled
+  with USE_MAX_ALLOWED_FOOTPRINT set.
+*/
+void mspace_set_max_allowed_footprint(mspace msp, size_t bytes);
+
+/*
+  mspace_max_footprint() returns the maximum number of bytes obtained
+  from the system over the lifetime of this space.
+*/
+size_t mspace_max_footprint(mspace msp);
+
+
+#if !NO_MALLINFO
+/*
+  mspace_mallinfo behaves as mallinfo, but reports properties of
+  the given space.
+*/
+struct mallinfo mspace_mallinfo(mspace msp);
+#endif /* NO_MALLINFO */
+
+/*
+  mspace_malloc_stats behaves as malloc_stats, but reports
+  properties of the given space.
+*/
+void mspace_malloc_stats(mspace msp);
+
+/*
+  mspace_trim behaves as malloc_trim, but
+  operates within the given space.
+*/
+int mspace_trim(mspace msp, size_t pad);
+
+/*
+  An alias for mallopt.
+*/
+int mspace_mallopt(int, int);
+
+#endif  /* MSPACES */
+
+#ifdef __cplusplus
+};  /* end of extern "C" */
+#endif
+
+#endif /* MALLOC_280_H */
diff --git a/src/globals.h b/src/globals.h
index 73afb7c..b2f73fd 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -12,9 +12,9 @@
 typedef intptr_t word;
 typedef uintptr_t uword;
 
-const int KB = 1024;
-const int MB = KB * KB;
-const int GB = KB * KB * KB;
+const size_t KB = 1024;
+const size_t MB = KB * KB;
+const size_t GB = KB * KB * KB;
 const int kMaxInt = 0x7FFFFFFF;
 const int kMinInt = -kMaxInt - 1;
 
diff --git a/src/heap.cc b/src/heap.cc
new file mode 100644
index 0000000..bbdf80a
--- /dev/null
+++ b/src/heap.cc
@@ -0,0 +1,163 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#include "src/heap.h"
+#include "src/object.h"
+#include "src/space.h"
+
+namespace art {
+
+Space* Heap::space_ = NULL;
+
+size_t Heap::startup_size_ = 0;
+
+size_t Heap::maximum_size_ = 0;
+
+bool Heap::is_gc_running_ = false;
+
+HeapBitmap* Heap::mark_bitmap_ = NULL;
+
+HeapBitmap* Heap::live_bitmap_ = NULL;
+
+bool Heap::Init(size_t startup_size, size_t maximum_size) {
+  space_ = Space::Create(startup_size, maximum_size);
+  if (space_ == NULL) {
+    return false;
+  }
+
+  byte* base = space_->GetBase();
+  size_t num_bytes = space_->Size();
+
+  // Allocate the initial live bitmap.
+  scoped_ptr<HeapBitmap> live_bitmap(HeapBitmap::Create(base, num_bytes));
+  if (live_bitmap == NULL) {
+    return false;
+  }
+
+  // Allocate the initial mark bitmap.
+  scoped_ptr<HeapBitmap> mark_bitmap(HeapBitmap::Create(base, num_bytes));
+  if (mark_bitmap == NULL) {
+    return false;
+  }
+
+  startup_size_ = startup_size;
+  maximum_size_ = maximum_size;
+  live_bitmap_ = live_bitmap.release();
+  mark_bitmap_ = mark_bitmap.release();
+
+  // TODO: allocate the card table
+
+  return true;
+}
+
+void Heap::Destroy() {
+  delete space_;
+  delete mark_bitmap_;
+  delete live_bitmap_;
+}
+
+Object* Heap::Allocate(size_t size) {
+  // Fail impossible allocations.  TODO: collect soft references.
+  if (size > maximum_size_) {
+    return NULL;
+  }
+
+  Object* ptr = space_->AllocWithoutGrowth(size);
+  if (ptr != NULL) {
+    return ptr;
+  }
+
+  // The allocation failed.  If the GC is running, block until it
+  // completes and retry.
+  if (is_gc_running_) {
+    // The GC is concurrently tracing the heap.  Release the heap
+    // lock, wait for the GC to complete, and retrying allocating.
+    WaitForConcurrentGcToComplete();
+    ptr = space_->AllocWithoutGrowth(size);
+    if (ptr != NULL) {
+      return ptr;
+    }
+  }
+
+  // Another failure.  Our thread was starved or there may be too many
+  // live objects.  Try a foreground GC.  This will have no effect if
+  // the concurrent GC is already running.
+  CollectGarbage();
+  ptr = space_->AllocWithoutGrowth(size);
+  if (ptr != NULL) {
+    return ptr;
+  }
+
+  // Even that didn't work;  this is an exceptional state.
+  // Try harder, growing the heap if necessary.
+  ptr = space_->AllocWithGrowth(size);
+  if (ptr != NULL) {
+    //size_t new_footprint = dvmHeapSourceGetIdealFootprint();
+    size_t new_footprint = space_->MaxAllowedFootprint();
+    //TODO: may want to grow a little bit more so that the amount of free
+    //      space is equal to the old free space + the utilization slop for
+    //      the new allocation.
+    // LOGI_HEAP("Grow heap (frag case) to "
+    //           "%zu.%03zuMB for %zu-byte allocation",
+    //           FRACTIONAL_MB(newHeapSize), size);
+    LOG(INFO) << "Grow heap (frag case) to " << new_footprint
+              << "for " << size << "-byte allocation";
+    return ptr;
+  }
+
+  // Most allocations should have succeeded by now, so the heap is
+  // really full, really fragmented, or the requested size is really
+  // big.  Do another GC, collecting SoftReferences this time.  The VM
+  // spec requires that all SoftReferences have been collected and
+  // cleared before throwing an OOME.
+
+  //TODO: wait for the finalizers from the previous GC to finish
+  //collect_soft_refs:
+  LOG(INFO) << "Forcing collection of SoftReferences for "
+            << size << "-byte allocation";
+  //gcForMalloc(true);
+  CollectGarbage();
+  ptr = space_->AllocWithGrowth(size);
+  if (ptr != NULL) {
+    return ptr;
+  }
+  //TODO: maybe wait for finalizers and try one last time
+
+  //LOGE_HEAP("Out of memory on a %zd-byte allocation.", size);
+  LOG(ERROR) << "Out of memory on a " << size << " byte allocation";
+
+  //TODO: tell the HeapSource to dump its state
+  //dvmDumpThread(dvmThreadSelf(), false);
+
+  // TODO: stack trace
+  return NULL;
+}
+
+String* Heap::AllocStringFromModifiedUtf8(Class* java_lang_String,
+                                          Class* char_array,
+                                          const char* data) {
+  String* string = AllocString(java_lang_String);
+  uint32_t count = strlen(data);  // TODO
+  CharArray* array = AllocCharArray(char_array, count);
+  string->array_ = array;
+  string->count_ = count;
+  return string;
+}
+
+void Heap::CollectGarbage() {
+}
+
+void Heap::CollectGarbageInternal() {
+}
+
+void Heap::WaitForConcurrentGcToComplete() {
+}
+
+// Given the current contents of the active heap, increase the allowed
+// heap footprint to match the target utilization ratio.  This should
+// only be called immediately after a full garbage collection.
+void Heap::GrowForUtilization() {
+  LOG(FATAL) << "Unimplemented";
+}
+
+}  // namespace art
diff --git a/src/heap.h b/src/heap.h
index f7ae5a5..f35e3f8 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -6,52 +6,103 @@
 
 #include "src/globals.h"
 #include "src/object.h"
+#include "src/object_bitmap.h"
+#include "src/thread.h"
 
 namespace art {
 
+class Space;
+class HeapBitmap;
+
 class Heap {
  public:
-  static Heap* Create() {
-    Heap* new_heap = new Heap();
-    // TODO: should return NULL if the heap could not be created.
-    return new_heap;
+  static const size_t kStartupSize = 1 * MB;
+
+  static const size_t kMaximumSize = 16 * MB;
+
+  static bool Init() {
+    return Init(kStartupSize, kMaximumSize);
   }
 
-  ~Heap() {}
+  static bool Init(size_t staring_size, size_t maximum_size);
 
-  static Object* AllocRaw(size_t size, Class* klass) {
-    byte* raw = new byte[size]();
-    Object* object = reinterpret_cast<Object*>(raw);
-    object->klass_ = klass;
-    return object;
-  }
+  static void Destroy();
 
   static Object* AllocObject(Class* klass) {
-    return AllocRaw(klass->object_size_, klass);
+    return AllocObject(klass, klass->object_size_);
+  }
+
+  static Object* AllocObject(Class* klass, size_t num_bytes) {
+    Object* obj = Allocate(num_bytes);
+    if (obj != NULL) {
+      obj->klass_ = klass;
+    }
+    return obj;
   }
 
   static CharArray* AllocCharArray(Class* char_array, size_t length) {
     size_t size = sizeof(Array) + length * sizeof(uint16_t);
-    return reinterpret_cast<CharArray*>(AllocRaw(size, char_array));
+    Object* new_array = AllocObject(char_array, size);
+    if (new_array != NULL) {
+      char_array->klass_ = char_array;
+    }
+    return down_cast<CharArray*>(new_array);
   }
 
   static String* AllocString(Class* java_lang_String) {
-    return reinterpret_cast<String*>(AllocObject(java_lang_String));
+    return down_cast<String*>(AllocObject(java_lang_String));
   }
 
-  static String* AllocStringFromModifiedUtf8(Class* java_lang_String, Class* char_array, const char* data) {
-    String* string = AllocString(java_lang_String);
-    uint32_t count = strlen(data);  // TODO
-    CharArray* array = AllocCharArray(char_array, count);
-    string->array_ = array;
-    string->count_ = count;
-    return string;
+  static String* AllocStringFromModifiedUtf8(Class* java_lang_String,
+                                             Class* char_array,
+                                             const char* data);
+
+  // Initiates an explicit garbage collection.
+  static void CollectGarbage();
+
+  // Blocks the caller until the garbage collector becomes idle.
+  static void WaitForConcurrentGcToComplete();
+
+  static Mutex* GetLock() {
+    return lock_;
   }
 
  private:
-  Heap() {}
 
-  DISALLOW_COPY_AND_ASSIGN(Heap);
+  static Object* Allocate(size_t num_bytes);
+
+  static void CollectGarbageInternal();
+
+  static void GrowForUtilization();
+
+  static Mutex* lock_;
+
+  static Space* space_;
+
+  static HeapBitmap* mark_bitmap_;
+
+  static HeapBitmap* live_bitmap_;
+
+  static size_t startup_size_;
+
+  static size_t maximum_size_;
+
+  static bool is_gc_running_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Heap);
+};
+
+class HeapLock {
+ public:
+  HeapLock(Heap* heap) : lock_(heap->GetLock()) {
+    lock_->Lock();
+  }
+  ~HeapLock() {
+    lock_->Unlock();
+  }
+ private:
+  Mutex* lock_;
+  DISALLOW_COPY_AND_ASSIGN(HeapLock);
 };
 
 }  // namespace art
diff --git a/src/mark_stack.cc b/src/mark_stack.cc
new file mode 100644
index 0000000..1d66346
--- /dev/null
+++ b/src/mark_stack.cc
@@ -0,0 +1,48 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#include "src/mark_stack.h"
+
+#include <sys/mman.h>
+
+#include "src/globals.h"
+#include "src/logging.h"
+#include "src/scoped_ptr.h"
+
+namespace art {
+
+MarkStack* MarkStack::Create(size_t maximum_size) {
+  scoped_ptr<MarkStack> mark_stack(new MarkStack());
+  bool success = mark_stack->Init(maximum_size);
+  if (!success) {
+    return NULL;
+  } else {
+    return mark_stack.release();
+  }
+}
+
+bool MarkStack::Init(size_t maximum_size) {
+  size_t length = 64 * MB;
+  void* addr = mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_PRIVATE, -1, 0);
+  if (addr == MAP_FAILED) {
+    PLOG(ERROR) << "mmap failed";
+    return false;
+  }
+  base_ = reinterpret_cast<const Object**>(addr);
+  limit_ = reinterpret_cast<const Object**>((byte*)addr + length);
+  ptr_ = reinterpret_cast<Object const**>(addr);
+  int result = madvise(addr, length, MADV_DONTNEED);
+  if (result == -1) {
+    PLOG(WARNING) << "madvise failed";
+  }
+  return true;
+}
+
+MarkStack::~MarkStack() {
+  int result = munmap((void*)base_, limit_ - base_);
+  if (result == -1) {
+    PLOG(WARNING) << "munmap failed";
+  }
+}
+
+}  // namespace art
diff --git a/src/mark_stack.h b/src/mark_stack.h
new file mode 100644
index 0000000..3f9d5e9
--- /dev/null
+++ b/src/mark_stack.h
@@ -0,0 +1,59 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#ifndef ART_SRC_MARK_STACK_H_
+#define ART_SRC_MARK_STACK_H_
+
+#include "src/logging.h"
+#include "src/macros.h"
+
+namespace art {
+
+class Object;
+
+class MarkStack {
+ public:
+  MarkStack* Create(size_t maximum_size);
+
+  ~MarkStack();
+
+  void Push(const Object* obj) {
+    DCHECK(obj != NULL);
+    DCHECK_NE(ptr_, limit_);
+    *ptr_ = obj;
+    ++ptr_;
+  }
+
+  const Object* Pop() {
+    DCHECK_NE(ptr_, base_);
+    --ptr_;
+    DCHECK(*ptr_ != NULL);
+    return *ptr_;
+  }
+
+  bool IsEmpty() const {
+    return ptr_ == base_;
+  }
+
+ private:
+  MarkStack() :
+      base_(NULL), limit_(NULL), ptr_(NULL) {
+  }
+
+  bool Init(size_t maximum_size);
+
+  // Base of the mark stack.
+  const Object* const* base_;
+
+  // Exclusive limit of the mark stack.
+  const Object* const* limit_;
+
+  // Pointer to the top of the mark stack.
+  Object const**  ptr_;
+
+  DISALLOW_COPY_AND_ASSIGN(MarkStack);
+};
+
+}  // namespace art
+
+#endif  // ART_SRC_MARK_STACK_H_
diff --git a/src/mark_sweep.cc b/src/mark_sweep.cc
new file mode 100644
index 0000000..5ab9e3e
--- /dev/null
+++ b/src/mark_sweep.cc
@@ -0,0 +1,409 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#include "src/mark_sweep.h"
+
+#include "src/logging.h"
+#include "src/macros.h"
+#include "src/mark_stack.h"
+#include "src/object.h"
+#include "src/thread.h"
+
+#define CLZ(x) __builtin_clz(x)
+
+namespace art {
+
+size_t MarkSweep::reference_referent_offset_ = 0;  // TODO
+size_t MarkSweep::reference_queue_offset_ = 0;  // TODO
+size_t MarkSweep::reference_queueNext_offset_ = 0;  // TODO
+size_t MarkSweep::reference_pendingNext_offset_ = 0;  // TODO
+size_t MarkSweep::finalizer_reference_zombie_offset_ = 0;  // TODO
+
+void MarkSweep::MarkObject0(const Object* obj, bool check_finger) {
+  DCHECK(obj != NULL);
+  if (obj < condemned_) {
+    DCHECK(IsMarked(obj));
+    return;
+  }
+  bool is_marked = mark_bitmap_->Test(obj);
+  // This object was not previously marked.
+  if (!is_marked) {
+    mark_bitmap_->Set(obj);
+    if (check_finger && obj < finger_) {
+      // The object must be pushed on to the mark stack.
+      mark_stack_->Push(obj);
+    }
+  }
+}
+
+// Used to mark objects when recursing.  Recursion is done by moving
+// the finger across the bitmaps in address order and marking child
+// objects.  Any newly-marked objects whose addresses are lower than
+// the finger won't be visited by the bitmap scan, so those objects
+// need to be added to the mark stack.
+void MarkSweep::MarkObject(const Object* obj) {
+  if (obj != NULL) {
+    MarkObject0(obj, true);
+  }
+}
+
+// Marks all objects in the root set.
+void MarkSweep::MarkRoots() {
+  LOG(FATAL) << "Unimplemented";
+}
+
+void MarkSweep::ReMarkRoots()
+{
+  LOG(FATAL) << "Unimplemented";
+}
+
+// Scans instance fields.
+void MarkSweep::ScanInstanceFields(const Object* obj) {
+  DCHECK(obj != NULL);
+  DCHECK(obj->GetClass() != NULL);
+  uint32_t ref_offsets = obj->GetClass()->GetReferenceOffsets();
+  if (ref_offsets != CLASS_WALK_SUPER) {
+    // Found a reference offset bitmap.  Mark the specified offsets.
+    while (ref_offsets != 0) {
+      size_t right_shift = CLZ(ref_offsets);
+      size_t byte_offset = CLASS_OFFSET_FROM_CLZ(right_shift);
+      const Object* ref = obj->GetFieldObject(byte_offset);
+      MarkObject(ref);
+      ref_offsets &= ~(CLASS_HIGH_BIT >> right_shift);
+    }
+  } else {
+    // There is no reference offset bitmap for this class.  Walk up
+    // the class inheritance hierarchy and find reference offsets the
+    // hard way.
+    for (Class *klass = obj->GetClass();
+         klass != NULL;
+         klass = klass->GetSuperClass()) {
+      for (size_t i = 0; i < klass->NumReferenceInstanceFields(); ++i) {
+        size_t field_offset = klass->GetInstanceField(i)->GetOffset();
+        const Object* ref = obj->GetFieldObject(field_offset);
+        MarkObject(ref);
+      }
+    }
+  }
+}
+
+// Scans the static fields of a class object.
+void MarkSweep::ScanStaticFields(const Class* klass) {
+  DCHECK(klass != NULL);
+  for (size_t i = 0; i < klass->NumStaticFields(); ++i) {
+    // char ch = clazz->sfields[i].signature[0];
+    const StaticField* static_field = klass->GetStaticField(i);
+    char ch = static_field->GetType();
+    if (ch == '[' || ch == 'L') {
+      // Object *obj = clazz->sfields[i].value.l;
+      // markObject(obj, ctx);
+      const Object* obj = static_field->GetObject();
+      MarkObject(obj);
+    }
+  }
+}
+
+void MarkSweep::ScanInterfaces(const Class* klass) {
+  DCHECK(klass != NULL);
+  for (size_t i = 0; i < klass->NumInterfaces(); ++i) {
+    MarkObject(klass->GetInterface(i));
+  }
+}
+
+// Scans the header, static field references, and interface pointers
+// of a class object.
+void MarkSweep::ScanClass(const Object* obj) {
+  DCHECK(obj != NULL);
+  DCHECK(obj->IsClass());
+  const Class* klass = obj->AsClass();
+  MarkObject(klass->GetClass());
+  if (klass->IsArray()) {
+    MarkObject(klass->GetComponentType());
+  }
+  if (klass->IsLoaded()) {
+    MarkObject(klass->GetSuperClass());
+  }
+  MarkObject(klass->GetClassLoader());
+  ScanInstanceFields(obj);
+  ScanStaticFields(klass);
+  // TODO: scan methods
+  // TODO: scan instance fields
+  if (klass->IsLoaded()) {
+    ScanInterfaces(klass);
+  }
+}
+
+// Scans the header of all array objects.  If the array object is
+// specialized to a reference type, scans the array data as well.
+void MarkSweep::ScanArray(const Object *obj) {
+  DCHECK(obj != NULL);
+  DCHECK(obj->GetClass() != NULL);
+  MarkObject(obj->GetClass());
+  if (obj->IsObjectArray()) {
+    const ObjectArray* array = obj->AsObjectArray();
+    for (size_t i = 0; i < array->GetLength(); ++i) {
+      const Object* element = array->Get(i);
+      MarkObject(element);
+    }
+  }
+}
+
+void MarkSweep::EnqueuePendingReference(Object* ref, Object** list) {
+  DCHECK(ref != NULL);
+  DCHECK(list != NULL);
+  size_t offset = reference_pendingNext_offset_;
+  if (*list == NULL) {
+    ref->SetFieldObject(offset, ref);
+    *list = ref;
+  } else {
+    Object *head = (*list)->GetFieldObject(offset);
+    ref->SetFieldObject(offset, head);
+    (*list)->SetFieldObject(offset, ref);
+  }
+}
+
+Object* MarkSweep::DequeuePendingReference(Object** list) {
+  DCHECK(list != NULL);
+  DCHECK(*list != NULL);
+  size_t offset = reference_pendingNext_offset_;
+  Object* head = (*list)->GetFieldObject(offset);
+  Object* ref;
+  if (*list == head) {
+    ref = *list;
+    *list = NULL;
+  } else {
+    Object *next = head->GetFieldObject(offset);
+    (*list)->SetFieldObject(offset, next);
+    ref = head;
+  }
+  ref->SetFieldObject(offset, NULL);
+  return ref;
+}
+
+// Process the "referent" field in a java.lang.ref.Reference.  If the
+// referent has not yet been marked, put it on the appropriate list in
+// the gcHeap for later processing.
+void MarkSweep::DelayReferenceReferent(Object* obj) {
+  DCHECK(obj != NULL);
+  DCHECK(obj->GetClass() != NULL);
+  //DCHECK(IS_CLASS_FLAG_SET(obj->clazz, CLASS_ISREFERENCE));
+  Object* pending = obj->GetFieldObject(reference_pendingNext_offset_);
+  Object* referent = obj->GetFieldObject(reference_referent_offset_);
+  if (pending == NULL && referent != NULL && !IsMarked(referent)) {
+    Object **list = NULL;
+    if (obj->IsSoftReference()) {
+      list = &soft_reference_list_;
+    } else if (obj->IsWeakReference()) {
+      list = &weak_reference_list_;
+    } else if (obj->IsFinalizerReference()) {
+      list = &finalizer_reference_list_;
+    } else if (obj->IsPhantomReference()) {
+      list = &phantom_reference_list_;
+    }
+    DCHECK(list != NULL);
+    EnqueuePendingReference(obj, list);
+  }
+}
+
+// Scans the header and field references of a data object.  If the
+// scanned object is a reference subclass, it is scheduled for later
+// processing
+void MarkSweep::ScanDataObject(const Object *obj) {
+  DCHECK(obj != NULL);
+  DCHECK(obj->GetClass() != NULL);
+  MarkObject(obj->GetClass());
+  ScanInstanceFields(obj);
+  if (obj->IsReference()) {
+    DelayReferenceReferent(const_cast<Object*>(obj));
+  }
+}
+
+// Scans an object reference.  Determines the type of the reference
+// and dispatches to a specialized scanning routine.
+void MarkSweep::ScanObject(const Object* obj) {
+  DCHECK(obj != NULL);
+  DCHECK(obj->GetClass() != NULL);
+  DCHECK(IsMarked(obj));
+  if (obj->IsClass()) {
+    ScanClass(obj);
+  } else if (obj->IsArray()) {
+    ScanArray(obj);
+  } else {
+    ScanDataObject(obj);
+  }
+}
+
+// Scan anything that's on the mark stack.  We can't use the bitmaps
+// anymore, so use a finger that points past the end of them.
+void MarkSweep::ProcessMarkStack() {
+  while (!mark_stack_->IsEmpty()) {
+    const Object *obj = mark_stack_->Pop();
+    ScanObject(obj);
+  }
+}
+
+void MarkSweep::ScanDirtyObjects() {
+  ProcessMarkStack();
+}
+
+void MarkSweep::ClearReference(Object* ref) {
+  DCHECK(ref != NULL);
+  ref->SetFieldObject(reference_referent_offset_, NULL);
+}
+
+bool MarkSweep::IsEnqueuable(const Object* ref) {
+  DCHECK(ref != NULL);
+  const Object* queue = ref->GetFieldObject(reference_queue_offset_);
+  const Object* queue_next = ref->GetFieldObject(reference_queueNext_offset_);
+  return (queue != NULL) && (queue_next == NULL);
+}
+
+void MarkSweep::EnqueueReference(Object* ref) {
+  DCHECK(ref != NULL);
+  CHECK(ref->GetFieldObject(reference_queue_offset_) != NULL);
+  CHECK(ref->GetFieldObject(reference_queueNext_offset_) == NULL);
+  EnqueuePendingReference(ref, &cleared_reference_list_);
+}
+
+// Walks the reference list marking any references subject to the
+// reference clearing policy.  References with a black referent are
+// removed from the list.  References with white referents biased
+// toward saving are blackened and also removed from the list.
+void MarkSweep::PreserveSomeSoftReferences(Object** list) {
+  DCHECK(list != NULL);
+  Object* clear = NULL;
+  size_t counter = 0;
+  while (*list != NULL) {
+    Object* ref = DequeuePendingReference(list);
+    Object* referent = ref->GetFieldObject(reference_referent_offset_);
+    if (referent == NULL) {
+      // Referent was cleared by the user during marking.
+      continue;
+    }
+    bool is_marked = IsMarked(referent);
+    if (!is_marked && ((++counter) & 1)) {
+      // Referent is white and biased toward saving, mark it.
+      MarkObject(referent);
+      is_marked = true;
+    }
+    if (!is_marked) {
+      // Referent is white, queue it for clearing.
+      EnqueuePendingReference(ref, &clear);
+    }
+  }
+  *list = clear;
+  // Restart the mark with the newly black references added to the
+  // root set.
+  ProcessMarkStack();
+}
+
+// Unlink the reference list clearing references objects with white
+// referents.  Cleared references registered to a reference queue are
+// scheduled for appending by the heap worker thread.
+void MarkSweep::ClearWhiteReferences(Object** list) {
+  DCHECK(list != NULL);
+  size_t offset = reference_referent_offset_;
+  while (*list != NULL) {
+    Object *ref = DequeuePendingReference(list);
+    Object *referent = ref->GetFieldObject(offset);
+    if (referent != NULL && !IsMarked(referent)) {
+      // Referent is white, clear it.
+      ClearReference(ref);
+      if (IsEnqueuable(ref)) {
+        EnqueueReference(ref);
+      }
+    }
+  }
+  DCHECK(*list == NULL);
+}
+
+// Enqueues finalizer references with white referents.  White
+// referents are blackened, moved to the zombie field, and the
+// referent field is cleared.
+void MarkSweep::EnqueueFinalizerReferences(Object** list) {
+  DCHECK(list != NULL);
+  size_t referent_offset = reference_referent_offset_;
+  size_t zombie_offset = finalizer_reference_zombie_offset_;
+  bool has_enqueued = false;
+  while (*list != NULL) {
+    Object* ref = DequeuePendingReference(list);
+    Object* referent = ref->GetFieldObject(referent_offset);
+    if (referent != NULL && !IsMarked(referent)) {
+      MarkObject(referent);
+      // If the referent is non-null the reference must queuable.
+      DCHECK(IsEnqueuable(ref));
+      ref->SetFieldObject(zombie_offset, referent);
+      ClearReference(ref);
+      EnqueueReference(ref);
+      has_enqueued = true;
+    }
+  }
+  if (has_enqueued) {
+    ProcessMarkStack();
+  }
+  DCHECK(*list == NULL);
+}
+
+/*
+ * Process reference class instances and schedule finalizations.
+ */
+void MarkSweep::ProcessReferences(Object** soft_references, bool clear_soft,
+                                  Object** weak_references,
+                                  Object** finalizer_references,
+                                  Object** phantom_references) {
+  DCHECK(soft_references != NULL);
+  DCHECK(weak_references != NULL);
+  DCHECK(finalizer_references != NULL);
+  DCHECK(phantom_references != NULL);
+
+  // Unless we are in the zygote or required to clear soft references
+  // with white references, preserve some white referents.
+  if (clear_soft) {
+    PreserveSomeSoftReferences(soft_references);
+  }
+
+  // Clear all remaining soft and weak references with white
+  // referents.
+  ClearWhiteReferences(soft_references);
+  ClearWhiteReferences(weak_references);
+
+  // Preserve all white objects with finalize methods and schedule
+  // them for finalization.
+  EnqueueFinalizerReferences(finalizer_references);
+
+  // Clear all f-reachable soft and weak references with white
+  // referents.
+  ClearWhiteReferences(soft_references);
+  ClearWhiteReferences(weak_references);
+
+  // Clear all phantom references with white referents.
+  ClearWhiteReferences(phantom_references);
+
+  // At this point all reference lists should be empty.
+  DCHECK(*soft_references == NULL);
+  DCHECK(*weak_references == NULL);
+  DCHECK(*finalizer_references == NULL);
+  DCHECK(*phantom_references == NULL);
+}
+
+// Pushes a list of cleared references out to the managed heap.
+void MarkSweep::EnqueueClearedReferences(Object** cleared) {
+  DCHECK(cleared != NULL);
+  if (*cleared != NULL) {
+    Thread* self = Thread::Current();
+    DCHECK(self != NULL);
+    // TODO: Method *meth = gDvm.methJavaLangRefReferenceQueueAdd;
+    // DCHECK(meth != NULL);
+    // JValue unused;
+    // Object *reference = *cleared;
+    // TODO: dvmCallMethod(self, meth, NULL, &unused, reference);
+    LOG(FATAL) << "Unimplemented";
+    *cleared = NULL;
+  }
+}
+
+MarkSweep::~MarkSweep() {
+  mark_bitmap_->Clear();
+}
+
+}  // namespace art
diff --git a/src/mark_sweep.h b/src/mark_sweep.h
new file mode 100644
index 0000000..98fbf1b
--- /dev/null
+++ b/src/mark_sweep.h
@@ -0,0 +1,133 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#ifndef ART_SRC_MARK_SWEEP_H_
+#define ART_SRC_MARK_SWEEP_H_
+
+#include "src/macros.h"
+#include "src/mark_stack.h"
+#include "src/object_bitmap.h"
+
+namespace art {
+
+class Class;
+class Object;
+
+class MarkSweep {
+ public:
+  ~MarkSweep();
+
+  // Marks the root set at the start of a garbage collection.
+  void MarkRoots();
+
+  // Remarks the root set after completing the concurrent mark.
+  void ReMarkRoots();
+
+  // Sweeps unmarked objects to complete the garbage collection.
+  void Sweep();
+
+ private:
+  // Returns true if the object has its bit set in the mark bitmap.
+  bool IsMarked(const Object* object) const {
+    return mark_bitmap_->Test(object);
+  }
+
+  // Marks an object.
+  void MarkObject(const Object* obj);
+
+  // Yuck.
+  void MarkObject0(const Object* obj, bool check_finger);
+
+  // Blackens an object.
+  void ScanObject(const Object* obj);
+
+  // Grays references in instance fields.
+  void ScanInstanceFields(const Object* obj);
+
+  // Blackens a class object.
+  void ScanClass(const Object* obj);
+
+  // Grays references in static fields.
+  void ScanStaticFields(const Class* klass);
+
+  // Grays interface class objects.
+  void ScanInterfaces(const Class* klass);
+
+  // Grays references in an array.
+  void ScanArray(const Object* obj);
+
+  void ScanDataObject(const Object* obj);
+
+  // Blackens objects grayed during a garbage collection.
+  void ScanDirtyObjects();
+
+  // Schedules an unmarked object for reference processing.
+  void DelayReferenceReferent(Object* reference);
+
+  // Recursively blackens objects on the mark stack.
+  void ProcessMarkStack();
+
+  // Adds a reference to the tail of a circular queue of references.
+  static void EnqueuePendingReference(Object* ref, Object** list);
+
+  // Removes the reference at the head of a circular queue of
+  // references.
+  static Object* DequeuePendingReference(Object** list);
+
+  // Sets the referent field of a reference object to null.
+  static void ClearReference(Object* reference);
+
+  // Returns true if the reference object has not yet been enqueued.
+  static bool IsEnqueuable(const Object* ref);
+
+  void EnqueueReference(Object* ref);
+
+  void EnqueueFinalizerReferences(Object** ref);
+
+  void PreserveSomeSoftReferences(Object** ref);
+
+  void EnqueueClearedReferences(Object** cleared_references);
+
+  void ClearWhiteReferences(Object** list);
+
+  void ProcessReferences(Object** soft_references, bool clear_soft,
+                         Object** weak_references,
+                         Object** finalizer_references,
+                         Object** phantom_references);
+
+  MarkStack* mark_stack_;
+
+  HeapBitmap* mark_bitmap_;
+
+  // HeapBitmap* alloc_bitmap_;
+
+  Object* finger_;
+
+  Object* condemned_;
+
+  Object* soft_reference_list_;
+
+  Object* weak_reference_list_;
+
+  Object* finalizer_reference_list_;
+
+  Object* phantom_reference_list_;
+
+  Object* cleared_reference_list_;
+
+  static size_t reference_referent_offset_;
+
+  static size_t reference_queue_offset_;
+
+  static size_t reference_queueNext_offset_;
+
+  static size_t reference_pendingNext_offset_;
+
+  static size_t finalizer_reference_zombie_offset_;
+
+  DISALLOW_COPY_AND_ASSIGN(MarkSweep);
+};
+
+}  // namespace art
+
+#endif  // ART_SRC_MARK_SWEEP_H_
diff --git a/src/mspace.c b/src/mspace.c
new file mode 100644
index 0000000..2a57816
--- /dev/null
+++ b/src/mspace.c
@@ -0,0 +1,291 @@
+/* Copyright 2006 The Android Open Source Project */
+
+/* A wrapper file for dlmalloc.c that compiles in the
+ * mspace_*() functions, which provide an interface for
+ * creating multiple heaps.
+ */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <sys/ioctl.h>
+
+#include <cutils/ashmem.h>
+
+/* It's a pain getting the mallinfo stuff to work
+ * with Linux, OSX, and klibc, so just turn it off
+ * for now.
+ * TODO: make mallinfo work
+ */
+#define NO_MALLINFO 1
+
+/* Allow setting the maximum heap footprint.
+ */
+#define USE_MAX_ALLOWED_FOOTPRINT 1
+
+/* Don't try to trim memory.
+ * TODO: support this.
+ */
+#define MORECORE_CANNOT_TRIM 1
+
+/* Use mmap()d anonymous memory to guarantee
+ * that an mspace is contiguous.
+ *
+ * create_mspace() won't work right if this is
+ * defined, so hide the definition of it and
+ * break any users at build time.
+ */
+#define USE_CONTIGUOUS_MSPACES 1
+#if USE_CONTIGUOUS_MSPACES
+/* This combination of settings forces sys_alloc()
+ * to always use MORECORE().  It won't expect the
+ * results to be contiguous, but we'll guarantee
+ * that they are.
+ */
+#define HAVE_MMAP 0
+#define HAVE_MORECORE 1
+#define MORECORE_CONTIGUOUS 0
+/* m is always the appropriate local when MORECORE() is called. */
+#define MORECORE(S) contiguous_mspace_morecore(m, S)
+#define create_mspace   HIDDEN_create_mspace_HIDDEN
+#define destroy_mspace   HIDDEN_destroy_mspace_HIDDEN
+typedef struct malloc_state *mstate0;
+static void *contiguous_mspace_morecore(mstate0 m, ssize_t nb);
+#endif /* USE_CONTIGUOUS_MSPACES */
+
+#define MSPACES 1
+#define ONLY_MSPACES 1
+#include "dlmalloc.c"
+
+#ifndef PAGESIZE
+#define PAGESIZE  mparams.page_size
+#endif
+
+#define ALIGN_UP(p, alignment) \
+    (((uintptr_t)(p) + (alignment)-1) & ~((alignment)-1))
+
+/* A direct copy of dlmalloc_usable_size(),
+ * which isn't compiled in when ONLY_MSPACES is set.
+ * The mspace parameter isn't actually necessary,
+ * but we include it to be consistent with the
+ * rest of the mspace_*() functions.
+ */
+size_t mspace_usable_size(mspace _unused, const void* mem) {
+  if (mem != 0) {
+    const mchunkptr p = mem2chunk(mem);
+    if (cinuse(p))
+      return chunksize(p) - overhead_for(p);
+  }
+  return 0;
+}
+
+#if USE_CONTIGUOUS_MSPACES
+#include <sys/mman.h>
+#include <limits.h>
+
+#define CONTIG_STATE_MAGIC  0xf00dd00d
+struct mspace_contig_state {
+  unsigned int magic;
+  char *brk;
+  char *top;
+  mspace m;
+};
+
+static void *contiguous_mspace_morecore(mstate m, ssize_t nb) {
+  struct mspace_contig_state *cs;
+  char *oldbrk;
+  const unsigned int pagesize = PAGESIZE;
+
+  cs = (struct mspace_contig_state *)((uintptr_t)m & ~(pagesize-1));
+  assert(cs->magic == CONTIG_STATE_MAGIC);
+  assert(cs->m == m);
+assert(nb >= 0);  //xxx deal with the trim case
+
+  oldbrk = cs->brk;
+  if (nb > 0) {
+    /* Break to the first page boundary that satisfies the request.
+     */
+    char *newbrk = (char *)ALIGN_UP(oldbrk + nb, pagesize);
+    if (newbrk > cs->top)
+      return CMFAIL;
+
+    /* Update the protection on the underlying memory.
+     * Pages we've given to dlmalloc are read/write, and
+     * pages we haven't are not accessable (read or write
+     * will cause a seg fault).
+     */
+    if (mprotect(cs, newbrk - (char *)cs, PROT_READ | PROT_WRITE) < 0)
+      return CMFAIL;
+    if (newbrk != cs->top) {
+      if (mprotect(newbrk, cs->top - newbrk, PROT_NONE) < 0)
+        return CMFAIL;
+    }
+
+    cs->brk = newbrk;
+
+    /* Make sure that dlmalloc will merge this block with the
+     * initial block that was passed to create_mspace_with_base().
+     * We don't care about extern vs. non-extern, so just clear it.
+     */
+    m->seg.sflags &= ~EXTERN_BIT;
+  }
+
+  return oldbrk;
+}
+
+mspace create_contiguous_mspace_with_base(size_t starting_capacity,
+    size_t max_capacity, int locked, void *base) {
+  struct mspace_contig_state *cs;
+  unsigned int pagesize;
+  mstate m;
+
+  init_mparams();
+  pagesize = PAGESIZE;
+  assert(starting_capacity <= max_capacity);
+  assert(((uintptr_t)base & (pagesize-1)) == 0);
+  assert(((uintptr_t)max_capacity & (pagesize-1)) == 0);
+  starting_capacity = (size_t)ALIGN_UP(starting_capacity, pagesize);
+
+  /* Make the first page read/write. dlmalloc needs to use that page.
+   */
+  if (mprotect(base, starting_capacity, PROT_READ | PROT_WRITE) < 0) {
+    goto error;
+  }
+
+  /* Create the mspace, pointing to the memory given.
+   */
+  m = create_mspace_with_base((char *)base + sizeof(*cs), starting_capacity,
+                              locked);
+  if (m == (mspace)0) {
+    goto error;
+  }
+  /* Make sure that m is in the same page as base.
+   */
+  assert(((uintptr_t)m & (uintptr_t)~(pagesize-1)) == (uintptr_t)base);
+  /* Use some space for the information that our MORECORE needs.
+   */
+  cs = (struct mspace_contig_state *)base;
+
+  /* Find out exactly how much of the memory the mspace
+   * is using.
+   */
+  cs->brk = m->seg.base + m->seg.size;
+  cs->top = (char *)base + max_capacity;
+
+  assert((char *)base <= cs->brk);
+  assert(cs->brk <= cs->top);
+  /* Prevent access to the memory we haven't handed out yet.
+   */
+  if (cs->brk != cs->top) {
+    /* mprotect() requires page-aligned arguments, but it's possible
+     * for cs->brk not to be page-aligned at this point.
+     */
+    char *prot_brk = (char *)ALIGN_UP(cs->brk, pagesize);
+    if ((mprotect(base, prot_brk - (char *)base, PROT_READ | PROT_WRITE) < 0) ||
+        (mprotect(prot_brk, cs->top - prot_brk, PROT_NONE) < 0)) {
+      goto error;
+    }
+  }
+
+  cs->m = m;
+  cs->magic = CONTIG_STATE_MAGIC;
+
+  return (mspace)m;
+
+error:
+  return (mspace)0;
+}
+
+mspace create_contiguous_mspace_with_name(size_t starting_capacity,
+    size_t max_capacity, int locked, char const *name) {
+  int fd;
+  char buf[ASHMEM_NAME_LEN] = "mspace";
+  void *base;
+  unsigned int pagesize;
+  mstate m;
+
+  if (starting_capacity > max_capacity)
+    return (mspace)0;
+
+  init_mparams();
+  pagesize = PAGESIZE;
+
+  /* Create the anonymous memory that will back the mspace.
+   * This reserves all of the virtual address space we could
+   * ever need.  Physical pages will be mapped as the memory
+   * is touched.
+   *
+   * Align max_capacity to a whole page.
+   */
+  max_capacity = (size_t)ALIGN_UP(max_capacity, pagesize);
+
+  if (name)
+    snprintf(buf, sizeof(buf), "mspace/%s", name);
+#ifdef USE_ASHMEM
+  fd = ashmem_create_region(buf, max_capacity);
+  if (fd < 0)
+    return (mspace)0;
+  base = mmap(NULL, max_capacity, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+  close(fd);
+#else
+  fd = -1;
+  base = mmap(NULL, max_capacity, PROT_READ | PROT_WRITE,
+              MAP_PRIVATE | MAP_ANONYMOUS, fd, 0);
+#endif /* USE_ASHMEM */
+
+  if (base == MAP_FAILED)
+    return (mspace)0;
+
+  /* Make sure that base is at the beginning of a page.
+   */
+  assert(((uintptr_t)base & (pagesize-1)) == 0);
+
+  m = create_contiguous_mspace_with_base(starting_capacity, max_capacity,
+                                         locked, base);
+  if (m == 0) {
+    munmap(base, max_capacity);
+  }
+  return m;
+}
+
+mspace create_contiguous_mspace(size_t starting_capacity,
+    size_t max_capacity, int locked) {
+  return create_contiguous_mspace_with_name(starting_capacity,
+      max_capacity, locked, NULL);
+}
+
+size_t destroy_contiguous_mspace(mspace msp) {
+  mstate ms = (mstate)msp;
+
+  if (ok_magic(ms)) {
+    struct mspace_contig_state *cs;
+    size_t length;
+    const unsigned int pagesize = PAGESIZE;
+
+    cs = (struct mspace_contig_state *)((uintptr_t)ms & ~(pagesize-1));
+    assert(cs->magic == CONTIG_STATE_MAGIC);
+    assert(cs->m == ms);
+
+    length = cs->top - (char *)cs;
+    if (munmap((char *)cs, length) != 0)
+      return length;
+  }
+  else {
+    USAGE_ERROR_ACTION(ms, ms);
+  }
+  return 0;
+}
+
+void *contiguous_mspace_sbrk0(mspace msp) {
+    struct mspace_contig_state *cs;
+    mstate ms;
+    const unsigned int pagesize = PAGESIZE;
+
+    ms = (mstate)msp;
+    cs = (struct mspace_contig_state *)((uintptr_t)ms & ~(pagesize-1));
+    assert(cs->magic == CONTIG_STATE_MAGIC);
+    assert(cs->m == ms);
+    return cs->brk;
+}
+#endif /* USE_CONTIGUOUS_MSPACES */
diff --git a/src/mspace.h b/src/mspace.h
new file mode 100644
index 0000000..b22d9a4
--- /dev/null
+++ b/src/mspace.h
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* A wrapper file for dlmalloc.h that defines prototypes for the
+ * mspace_*() functions, which provide an interface for creating
+ * multiple heaps.
+ */
+
+#ifndef MSPACE_H_
+#define MSPACE_H_
+
+/* It's a pain getting the mallinfo stuff to work
+ * with Linux, OSX, and klibc, so just turn it off
+ * for now.
+ * TODO: make mallinfo work
+ */
+#define NO_MALLINFO 1
+
+/* Allow setting the maximum heap footprint.
+ */
+#define USE_MAX_ALLOWED_FOOTPRINT 1
+
+#define USE_CONTIGUOUS_MSPACES 1
+#if USE_CONTIGUOUS_MSPACES
+#define HAVE_MMAP 0
+#define HAVE_MORECORE 1
+#define MORECORE_CONTIGUOUS 0
+#endif
+
+#define MSPACES 1
+#define ONLY_MSPACES 1
+#include "dlmalloc.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+  mspace_usable_size(void* p);
+
+  Returns the number of bytes you can actually use in
+  an allocated chunk, which may be more than you requested (although
+  often not) due to alignment and minimum size constraints.
+  You can use this many bytes without worrying about
+  overwriting other allocated objects. This is not a particularly great
+  programming practice. mspace_usable_size can be more useful in
+  debugging and assertions, for example:
+
+  p = mspace_malloc(msp, n);
+  assert(mspace_usable_size(msp, p) >= 256);
+*/
+size_t mspace_usable_size(mspace, const void*);
+
+#if USE_CONTIGUOUS_MSPACES
+/*
+  Similar to create_mspace(), but the underlying memory is
+  guaranteed to be contiguous.  No more than max_capacity
+  bytes is ever allocated to the mspace.
+ */
+mspace create_contiguous_mspace(size_t starting_capacity, size_t max_capacity,
+    int locked);
+
+/*
+   Identical to create_contiguous_mspace, but labels the mapping 'mspace/name'
+   instead of 'mspace'
+*/
+mspace create_contiguous_mspace_with_name(size_t starting_capacity,
+    size_t max_capacity, int locked, const char *name);
+
+/*
+   Identical to create_contiguous_mspace, but uses previously mapped memory.
+*/
+mspace create_contiguous_mspace_with_base(size_t starting_capacity,
+    size_t max_capacity, int locked, void *base);
+
+size_t destroy_contiguous_mspace(mspace msp);
+
+/*
+   Returns the position of the "break" within the given mspace.
+*/
+void *contiguous_mspace_sbrk0(mspace msp);
+#endif
+
+/*
+  Call the handler for each block in the specified mspace.
+  chunkptr and chunklen refer to the heap-level chunk including
+  the chunk overhead, and userptr and userlen refer to the
+  user-usable part of the chunk.  If the chunk is free, userptr
+  will be NULL and userlen will be 0.  userlen is not guaranteed
+  to be the same value passed into malloc() for a given chunk;
+  it is >= the requested size.
+ */
+void mspace_walk_heap(mspace msp,
+    void(*handler)(const void *chunkptr, size_t chunklen,
+        const void *userptr, size_t userlen, void *arg), void *harg);
+
+/*
+  mspace_walk_free_pages(handler, harg)
+
+  Calls the provided handler on each free region in the specified
+  mspace.  The memory between start and end are guaranteed not to
+  contain any important data, so the handler is free to alter the
+  contents in any way.  This can be used to advise the OS that large
+  free regions may be swapped out.
+
+  The value in harg will be passed to each call of the handler.
+ */
+void mspace_walk_free_pages(mspace msp,
+    void(*handler)(void *start, void *end, void *arg), void *harg);
+
+#ifdef __cplusplus
+};  /* end of extern "C" */
+#endif
+
+#endif /* MSPACE_H_ */
diff --git a/src/object.h b/src/object.h
index 49940e0..266822d 100644
--- a/src/object.h
+++ b/src/object.h
@@ -3,12 +3,13 @@
 #ifndef ART_SRC_OBJECT_H_
 #define ART_SRC_OBJECT_H_
 
-#include "src/assembler.h"
 #include "src/constants.h"
+#include "src/casts.h"
 #include "src/dex_file.h"
 #include "src/globals.h"
 #include "src/logging.h"
 #include "src/macros.h"
+#include "src/offsets.h"
 #include "src/stringpiece.h"
 #include "src/monitor.h"
 
@@ -22,6 +23,7 @@
 class Monitor;
 class Method;
 class Object;
+class ObjectArray;
 class StaticField;
 
 union JValue {
@@ -135,14 +137,76 @@
     monitor_->Wait(timeout, nanos);
   }
 
-  void SetObjectAt(size_t offset, Object* new_value) {
+  const Object* GetFieldObject(size_t field_offset) const {
+    const byte* raw_addr = reinterpret_cast<const byte*>(this) + field_offset;
+    return *reinterpret_cast<Object* const*>(raw_addr);
+  }
+
+  Object* GetFieldObject(size_t field_offset) {
+    return const_cast<Object*>(GetFieldObject(field_offset));
+  }
+
+  void SetFieldObject(size_t offset, Object* new_value) {
     byte* raw_addr = reinterpret_cast<byte*>(this) + offset;
     *reinterpret_cast<Object**>(raw_addr) = new_value;
     // TODO: write barrier
   }
 
+  bool IsClass() const {
+    LOG(FATAL) << "Unimplemented";
+    return true;
+  }
+
+  Class* AsClass() {
+    return down_cast<Class*>(this);
+  }
+
+  const Class* AsClass() const {
+    return down_cast<const Class*>(this);
+  }
+
+  bool IsObjectArray() const {
+    LOG(FATAL) << "Unimplemented";
+    return true;
+  }
+
+  const ObjectArray* AsObjectArray() const {
+    return down_cast<const ObjectArray*>(this);
+  }
+
+  bool IsReference() const {
+    LOG(FATAL) << "Unimplemented";
+    return true;
+  }
+
+  bool IsWeakReference() const {
+    LOG(FATAL) << "Unimplemented";
+    return true;
+  }
+
+  bool IsSoftReference() const {
+    LOG(FATAL) << "Unimplemented";
+    return true;
+  }
+
+  bool IsFinalizerReference() const {
+    LOG(FATAL) << "Unimplemented";
+    return true;
+  }
+
+  bool IsPhantomReference() const {
+    LOG(FATAL) << "Unimplemented";
+    return true;
+  }
+
+  bool IsArray() const {
+    LOG(FATAL) << "Unimplemented";
+    return true;
+  }
+
  public:
   Class* klass_;
+
   Monitor* monitor_;
 
  private:
@@ -286,6 +350,14 @@
     value_.d = d;
   }
 
+  Object* GetObject() {
+    return value_.l;
+  }
+
+  const Object* GetObject() const {
+    return value_.l;
+  }
+
   void SetObject(Object* l) {
     CHECK(GetType() == 'L' || GetType() == '[');
     value_.l = l;
@@ -542,6 +614,7 @@
   }
 
   Class* GetComponentType() const {
+    DCHECK(IsArray());
     return component_type_;
   }
 
@@ -558,18 +631,25 @@
     status_ = new_status;
   }
 
+  // Returns true if the class has failed to link.
   bool IsErroneous() const {
     return GetStatus() == kStatusError;
   }
 
+  // Returns true if the class has been verified.
   bool IsVerified() const {
     return GetStatus() >= kStatusVerified;
   }
 
+  // Returns true if the class has been linked.
   bool IsLinked() const {
     return GetStatus() >= kStatusResolved;
   }
 
+  bool IsLoaded() const {
+    return GetStatus() >= kStatusLoaded;
+  }
+
   // Returns true if this class is in the same packages as that class.
   bool IsInSamePackage(const Class* that) const;
 
@@ -642,26 +722,30 @@
   }
 
   size_t NumInstanceFields() const {
-    return num_ifields_;
+    return num_instance_fields_;
   }
 
+  // Returns the number of instance fields containing reference types.
   size_t NumReferenceInstanceFields() const {
-    return num_reference_ifields_;
+    return num_reference_instance_fields_;
   }
 
   InstanceField* GetInstanceField(uint32_t i) {  // TODO: uint16_t
+    DCHECK_LT(i, num_instance_fields_);
     return ifields_[i];
   }
 
   void SetInstanceField(uint32_t i, InstanceField* f) {  // TODO: uint16_t
+    DCHECK_LT(i, num_instance_fields_);
     ifields_[i] = f;
   }
 
   size_t NumStaticFields() const {
-    return num_sfields_;
+    return num_static_fields_;
   }
 
-  StaticField* GetStaticField(uint32_t i) {  // TODO: uint16_t
+  StaticField* GetStaticField(uint32_t i) const {  // TODO: uint16_t
+    DCHECK_LT(i, num_static_fields_);
     return sfields_[i];
   }
 
@@ -677,6 +761,15 @@
 
   Method* FindVirtualMethod(const StringPiece& name) const;
 
+  size_t NumInterfaces() const {
+    return interface_count_;
+  }
+
+  Class* GetInterface(uint32_t i) const {
+    DCHECK_LT(i, interface_count_);
+    return interfaces_[i];
+  }
+
   Method* FindDirectMethodLocally(const StringPiece& name,
                                   const StringPiece& descriptor) const;
 
@@ -791,10 +884,10 @@
   // All instance fields that refer to objects are guaranteed to be at
   // the beginning of the field list.  ifieldRefCount specifies the
   // number of reference fields.
-  size_t num_ifields_;
+  size_t num_instance_fields_;
 
   // number of fields that are object refs
-  size_t num_reference_ifields_;
+  size_t num_reference_instance_fields_;
   InstanceField** ifields_;
 
   // Bitmap of offsets of ifields.
@@ -804,7 +897,7 @@
   const char* source_file_;
 
   // Static fields
-  size_t num_sfields_;
+  size_t num_static_fields_;
   StaticField** sfields_;
 
  private:
@@ -821,6 +914,10 @@
 
 class Array : public Object {
  public:
+  uint32_t GetLength() const{
+    return length_;
+  }
+
   void SetLength(uint32_t length) {
     length_ = length;
   }
@@ -828,14 +925,30 @@
  private:
   // The number of array elements.
   uint32_t length_;
-  Array();
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Array);
 };
 
 class CharArray : public Array {
  private:
-  CharArray();
+  DISALLOW_IMPLICIT_CONSTRUCTORS(CharArray);
 };
 
+class ObjectArray : public Array {
+ public:
+  Object* Get(int32_t i) {
+    return NULL;
+  }
+
+  const Object* Get(int32_t i) const {
+    return NULL;
+  }
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(ObjectArray);
+};
+
+
 class String : public Object {
  public:
   CharArray* array_;
diff --git a/src/object_bitmap.cc b/src/object_bitmap.cc
new file mode 100644
index 0000000..7234143
--- /dev/null
+++ b/src/object_bitmap.cc
@@ -0,0 +1,197 @@
+// Copyright (C) 2008 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "src/object_bitmap.h"
+
+#include <sys/mman.h>
+
+#include "src/logging.h"
+#include "src/scoped_ptr.h"
+
+namespace art {
+
+#define CLZ(x) __builtin_clz(x)
+
+HeapBitmap* HeapBitmap::Create(byte* base, size_t length) {
+  scoped_ptr<HeapBitmap> bitmap(new HeapBitmap(base, length));
+  if (!bitmap->Init(base, length)) {
+    return NULL;
+  } else {
+    return bitmap.release();
+  }
+}
+
+// Initialize a HeapBitmap so that it points to a bitmap large enough
+// to cover a heap at <base> of <maxSize> bytes, where objects are
+// guaranteed to be kAlignment-aligned.
+bool HeapBitmap::Init(const byte* base, size_t max_size) {
+  CHECK(base != NULL);
+  size_t length = HB_OFFSET_TO_INDEX(max_size) * kWordSize;
+  void* words = mmap(NULL, length, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+  if (words == MAP_FAILED) {
+    LOG(ERROR) << "mmap failed";
+    return false;
+  }
+  words_ = static_cast<unsigned long*>(words);
+  num_bytes_ = length;
+  base_ = reinterpret_cast<uintptr_t>(base);
+  max_ = base_ - 1;
+  return true;
+}
+
+// Clean up any resources associated with the bitmap.
+HeapBitmap::~HeapBitmap() {
+  if (words_ != NULL) {
+    int result = munmap(words_, num_bytes_);
+    if (result == -1) {
+      PLOG(WARNING) << "munmap failed";
+    }
+    words_ = NULL;
+  }
+}
+
+// Fill the bitmap with zeroes.  Returns the bitmap's memory to the
+// system as a side-effect.
+void HeapBitmap::Clear() {
+  if (words_ != NULL) {
+    // This returns the memory to the system.  Successive page faults
+    // will return zeroed memory.
+    int result = madvise(words_, num_bytes_, MADV_DONTNEED);
+    if (result == -1) {
+      PLOG(WARNING) << "madvise failed";
+    }
+    max_ = base_ - 1;
+  }
+}
+
+// Return true iff <obj> is within the range of pointers that this
+// bitmap could potentially cover, even if a bit has not been set for
+// it.
+bool HeapBitmap::HasAddress(const void* obj) const {
+  if (obj != NULL) {
+    const uintptr_t offset = (uintptr_t)obj - base_;
+    const size_t index = HB_OFFSET_TO_INDEX(offset);
+    return index < num_bytes_ / kWordSize;
+  }
+  return false;
+}
+
+// Visits set bits in address order.  The callback is not permitted to
+// change the bitmap bits or max during the traversal.
+void HeapBitmap::Walk(HeapBitmap::Callback* callback, void* arg) {
+  CHECK(words_ != NULL);
+  CHECK(callback != NULL);
+  uintptr_t end = HB_OFFSET_TO_INDEX(max_ - base_);
+  for (uintptr_t i = 0; i <= end; ++i) {
+    unsigned long word = words_[i];
+    if (word != 0) {
+      unsigned long high_bit = 1 << (kBitsPerWord - 1);
+      uintptr_t ptr_base = HB_INDEX_TO_OFFSET(i) + base_;
+      while (word != 0) {
+        const int shift = CLZ(word);
+        Object* obj = (Object *)(ptr_base + shift * kAlignment);
+        (*callback)(obj, arg);
+        word &= ~(high_bit >> shift);
+      }
+    }
+  }
+}
+
+// Similar to Walk but the callback routine is permitted to change the
+// bitmap bits and max during traversal.  Used by the the root marking
+// scan exclusively.
+//
+// The callback is invoked with a finger argument.  The finger is a
+// pointer to an address not yet visited by the traversal.  If the
+// callback sets a bit for an address at or above the finger, this
+// address will be visited by the traversal.  If the callback sets a
+// bit for an address below the finger, this address will not be
+// visited.
+void HeapBitmap::ScanWalk(uintptr_t base, uintptr_t max,
+                          ScanCallback* callback, void* arg) {
+  CHECK(words_ != NULL);
+  CHECK(callback != NULL);
+  CHECK(base <= max);
+  CHECK(base >= base_);
+  CHECK(max <= max_);
+  uintptr_t end = HB_OFFSET_TO_INDEX(max - base);
+  for (uintptr_t i = 0; i <= end; ++i) {
+    unsigned long word = words_[i];
+    if (word != 0) {
+      unsigned long high_bit = 1 << (kBitsPerWord - 1);
+      uintptr_t ptr_base = HB_INDEX_TO_OFFSET(i) + base_;
+      void* finger = (void*)(HB_INDEX_TO_OFFSET(i + 1) + base_);
+      while (word != 0) {
+        const int shift = CLZ(word);
+        Object* obj = (Object*)(ptr_base + shift * kAlignment);
+        (*callback)(obj, finger, arg);
+        word &= ~(high_bit >> shift);
+      }
+      end = HB_OFFSET_TO_INDEX(max_ - base_);
+    }
+  }
+}
+
+// Walk through the bitmaps in increasing address order, and find the
+// object pointers that correspond to garbage objects.  Call
+// <callback> zero or more times with lists of these object pointers.
+//
+// The callback is not permitted to increase the max of either bitmap.
+void HeapBitmap::SweepWalk(const HeapBitmap& live_bitmap,
+                           const HeapBitmap& mark_bitmap,
+                           uintptr_t base, uintptr_t max,
+                           HeapBitmap::SweepCallback* callback, void* arg) {
+  CHECK(live_bitmap.words_ != NULL);
+  CHECK(mark_bitmap.words_ != NULL);
+  CHECK(live_bitmap.base_ == mark_bitmap.base_);
+  CHECK(live_bitmap.num_bytes_ == mark_bitmap.num_bytes_);
+  CHECK(callback != NULL);
+  CHECK(base <= max);
+  CHECK(base >= live_bitmap.base_);
+  CHECK(max <= live_bitmap.max_);
+  if (live_bitmap.max_ < live_bitmap.base_) {
+    // Easy case; both are obviously empty.
+    // TODO: this should never happen
+    return;
+  }
+  void* pointer_buf[4 * kBitsPerWord];
+  void** pb = pointer_buf;
+  size_t start = HB_OFFSET_TO_INDEX(base - live_bitmap.base_);
+  size_t end = HB_OFFSET_TO_INDEX(max - live_bitmap.base_);
+  unsigned long* live = live_bitmap.words_;
+  unsigned long* mark = mark_bitmap.words_;
+  for (size_t i = start; i <= end; i++) {
+    unsigned long garbage = live[i] & ~mark[i];
+    if (garbage != 0) {
+      unsigned long high_bit = 1 << (kBitsPerWord - 1);
+      uintptr_t ptr_base = HB_INDEX_TO_OFFSET(i) + live_bitmap.base_;
+      while (garbage != 0) {
+        int shift = CLZ(garbage);
+        garbage &= ~(high_bit >> shift);
+        *pb++ = (void*)(ptr_base + shift * kAlignment);
+      }
+      // Make sure that there are always enough slots available for an
+      // entire word of one bits.
+      if (pb >= &pointer_buf[ARRAYSIZE_UNSAFE(pointer_buf) - kBitsPerWord]) {
+        (*callback)(pb - pointer_buf, pointer_buf, arg);
+        pb = pointer_buf;
+      }
+    }
+  }
+  if (pb > pointer_buf) {
+    (*callback)(pb - pointer_buf, pointer_buf, arg);
+  }
+}
+
+}  // namespace art
diff --git a/src/object_bitmap.h b/src/object_bitmap.h
new file mode 100644
index 0000000..3e779b2
--- /dev/null
+++ b/src/object_bitmap.h
@@ -0,0 +1,138 @@
+// Copyright (C) 2008 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ART_SRC_OBJECT_BITMAP_H_
+#define ART_SRC_OBJECT_BITMAP_H_
+
+#include <limits.h>
+#include <stdint.h>
+
+#include "src/globals.h"
+#include "src/logging.h"
+
+namespace art {
+
+class Object;
+
+// <offset> is the difference from .base to a pointer address.
+// <index> is the index of .bits that contains the bit representing
+//         <offset>.
+#define HB_OFFSET_TO_INDEX(offset_) \
+    ((offset_) / kAlignment / kBitsPerWord)
+#define HB_INDEX_TO_OFFSET(index_) \
+    ((index_) * kAlignment * kBitsPerWord)
+
+#define HB_OFFSET_TO_BYTE_INDEX(offset_) \
+  (HB_OFFSET_TO_INDEX(offset_) * sizeof(*((HeapBitmap *)0)->words_))
+
+// Pack the bits in backwards so they come out in address order
+// when using CLZ.
+#define HB_OFFSET_TO_MASK(offset_) \
+    (1 << \
+        (31-(((uintptr_t)(offset_) / kAlignment) % kBitsPerWord)))
+
+class HeapBitmap {
+ public:
+  static const size_t kAlignment = 8;
+
+  typedef void Callback(Object *obj, void *arg);
+
+  typedef void ScanCallback(Object *obj, void *finger, void *arg);
+
+  typedef void SweepCallback(size_t numPtrs, void **ptrs, void *arg);
+
+  static HeapBitmap* Create(byte* base, size_t length);
+
+  ~HeapBitmap();
+
+  void Set(const Object* obj) {
+    Modify(obj, true);
+  }
+
+  void Clear(const Object* obj) {
+    Modify(obj, false);
+  }
+
+  void Clear();
+
+  bool Test(const Object* obj) {
+    CHECK(HasAddress(obj));
+    CHECK(words_ != NULL);
+    CHECK_GE((uintptr_t)obj, base_);
+    if ((uintptr_t)obj <= max_) {
+        const uintptr_t offset = (uintptr_t)obj - base_;
+        unsigned long word = words_[HB_OFFSET_TO_INDEX(offset)];
+        return (word & HB_OFFSET_TO_MASK(offset)) != 0;
+    } else {
+        return false;
+    }
+  }
+
+  bool HasAddress(const void* addr) const;
+
+  void Walk(Callback* callback, void* arg);
+
+  void ScanWalk(uintptr_t base, uintptr_t max,
+                ScanCallback* thunk, void* arg);
+
+  static void SweepWalk(const HeapBitmap& live,
+                        const HeapBitmap& mark,
+                        uintptr_t base, uintptr_t max,
+                        SweepCallback* thunk, void* arg);
+
+ private:
+  HeapBitmap(const void* base, size_t length)
+      : words_(NULL),
+        num_bytes_(length),
+        base_(reinterpret_cast<uintptr_t>(base)) {
+  };
+
+  void Modify(const Object* obj, bool do_set) {
+    uintptr_t addr = reinterpret_cast<uintptr_t>(obj);
+    CHECK_GE(addr, base_);
+    const uintptr_t offset = addr - base_;
+    const size_t index = HB_OFFSET_TO_INDEX(offset);
+    const unsigned long mask = HB_OFFSET_TO_MASK(offset);
+    CHECK_LT(index, num_bytes_ / kWordSize);
+    if (do_set) {
+      if (addr > max_) {
+        max_ = addr;
+      }
+      words_[index] |= mask;
+    } else {
+      words_[index] &= ~mask;
+    }
+  }
+
+  bool Init(const byte* base, size_t length);
+
+  unsigned long* words_;
+
+  size_t num_bytes_;
+
+  // The base address, which corresponds to the word containing the
+  // first bit in the bitmap.
+  uintptr_t base_;
+
+  // The highest pointer value ever returned by an allocation from
+  // this heap.  I.e., the highest address that may correspond to a
+  // set bit.  If there are no bits set, (max < base).
+  uintptr_t max_;
+
+  const char* name_;
+};
+
+}  // namespace art
+
+#endif  // ART_SRC_OBJECT_BITMAP_H_
diff --git a/src/offsets.cc b/src/offsets.cc
new file mode 100644
index 0000000..1dce268
--- /dev/null
+++ b/src/offsets.cc
@@ -0,0 +1,14 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#include "src/offsets.h"
+
+#include <iostream>  // NOLINT
+
+namespace art {
+
+std::ostream& operator<<(std::ostream& os, const Offset& offs) {
+  return os << offs.Int32Value();
+}
+
+}
diff --git a/src/offsets.h b/src/offsets.h
new file mode 100644
index 0000000..33f395f
--- /dev/null
+++ b/src/offsets.h
@@ -0,0 +1,49 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#ifndef ART_SRC_OFFSETS_H_
+#define ART_SRC_OFFSETS_H_
+
+#include <iostream>  // NOLINT
+#include "src/globals.h"
+
+namespace art {
+
+// Allow the meaning of offsets to be strongly typed
+class Offset {
+ public:
+  explicit Offset(size_t val) : val_(val) {}
+  int32_t Int32Value() const {
+    return static_cast<int32_t>(val_);
+  }
+  uint32_t Uint32Value() const {
+    return static_cast<uint32_t>(val_);
+  }
+ protected:
+  size_t val_;
+};
+std::ostream& operator<<(std::ostream& os, const Offset& offs);
+
+// Offsets relative to the current frame
+class FrameOffset : public Offset {
+ public:
+  explicit FrameOffset(size_t val) : Offset(val) {}
+  bool operator>(FrameOffset other) const { return val_ > other.val_; }
+  bool operator<(FrameOffset other) const { return val_ < other.val_; }
+};
+
+// Offsets relative to the current running thread
+class ThreadOffset : public Offset {
+ public:
+  explicit ThreadOffset(size_t val) : Offset(val) {}
+};
+
+// Offsets relative to an object
+class MemberOffset : public Offset {
+ public:
+  explicit MemberOffset(size_t val) : Offset(val) {}
+};
+
+}  // namespace art
+
+#endif  // ART_SRC_OFFSETS_H_
diff --git a/src/runtime.cc b/src/runtime.cc
index 28af9dd..3adaea7 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -14,7 +14,7 @@
 Runtime::~Runtime() {
   // TODO: use a smart pointer instead.
   delete class_linker_;
-  delete heap_;
+  Heap::Destroy();
   delete thread_list_;
 }
 
@@ -32,10 +32,9 @@
   PlatformAbort(file, line);
 
   // If we call abort(3) on a device, all threads in the process
-  // receive SIBABRT.
-  // debuggerd dumps the stack trace of the main thread, whether or not
-  // that was the thread that failed.
-  // By stuffing a value into a bogus address, we cause a segmentation
+  // receive SIGABRT.  debuggerd dumps the stack trace of the main
+  // thread, whether or not that was the thread that failed.  By
+  // stuffing a value into a bogus address, we cause a segmentation
   // fault in the current thread, and get a useful log from debuggerd.
   // We can also trivially tell the difference between a VM crash and
   // a deliberate abort by looking at the fault address.
@@ -57,7 +56,7 @@
 
 bool Runtime::Init() {
   thread_list_ = ThreadList::Create();
-  heap_ = Heap::Create();
+  Heap::Init(Heap::kStartupSize, Heap::kMaximumSize);
   Thread::Init();
   Thread* current_thread = Thread::Attach();
   thread_list_->Register(current_thread);
diff --git a/src/runtime.h b/src/runtime.h
index 9245f19..cbccccb 100644
--- a/src/runtime.h
+++ b/src/runtime.h
@@ -39,15 +39,13 @@
  private:
   static void PlatformAbort(const char*, int);
 
-  Runtime() : class_linker_(NULL), heap_(NULL), thread_list_(NULL) {}
+  Runtime() : class_linker_(NULL), thread_list_(NULL) {}
 
   // Initializes a new uninitialized runtime.
   bool Init();
 
   ClassLinker* class_linker_;
 
-  Heap* heap_;
-
   ThreadList* thread_list_;
 
   DISALLOW_COPY_AND_ASSIGN(Runtime);
diff --git a/src/space.cc b/src/space.cc
new file mode 100644
index 0000000..dc9950c
--- /dev/null
+++ b/src/space.cc
@@ -0,0 +1,130 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#include "src/space.h"
+
+#include <sys/mman.h>
+
+#include "src/logging.h"
+#include "src/mspace.h"
+#include "src/scoped_ptr.h"
+#include "src/utils.h"
+
+namespace art {
+
+Space* Space::Create(size_t startup_size, size_t maximum_size) {
+  scoped_ptr<Space> space(new Space(startup_size, maximum_size));
+  bool success = space->Init();
+  if (!success) {
+    return NULL;
+  } else {
+    return space.release();
+  }
+}
+
+void* Space::CreateMallocSpace(void* base,
+                               size_t startup_size,
+                               size_t maximum_size) {
+  errno = 0;
+  bool is_locked = false;
+  size_t commit_size = startup_size / 2;
+  void* msp = create_contiguous_mspace_with_base(commit_size, maximum_size,
+                                                 is_locked, base);
+  if (msp != NULL) {
+    // Do not permit the heap grow past the starting size without our
+    // intervention.
+    mspace_set_max_allowed_footprint(msp, startup_size);
+  } else {
+    // There is no guarantee that errno has meaning when the call
+    // fails, but it often does.
+    PLOG(ERROR) << "create_contiguous_mspace_with_base failed";
+  }
+  return msp;
+}
+
+bool Space::Init() {
+  if (!(startup_size_ <= maximum_size_)) {
+    return false;
+  }
+  size_t length = RoundUp(maximum_size_, 4096);
+  int prot = PROT_READ | PROT_WRITE;
+  int flags = MAP_PRIVATE | MAP_ANONYMOUS;
+  void* base = mmap(NULL, length, prot, flags, -1, 0);
+  if (base == MAP_FAILED) {
+    PLOG(ERROR) << "mmap failed";
+    return false;
+  }
+  base_ = static_cast<byte*>(base);
+  limit_ = base_ + length;
+  mspace_ = CreateMallocSpace(base, startup_size_, maximum_size_);
+  if (mspace_ == NULL) {
+    munmap(base_, length);
+    return false;
+  }
+  return true;
+}
+
+Space::~Space() {
+  if (base_ == NULL) {
+    return;
+  }
+  int result = munmap(base_, limit_ - base_);
+  if (result == -1) {
+    PLOG(WARNING) << "munmap failed";
+  }
+}
+
+Object* Space::AllocWithoutGrowth(size_t num_bytes) {
+  return reinterpret_cast<Object*>(mspace_calloc(mspace_, 1, num_bytes));
+}
+
+Object* Space::AllocWithGrowth(size_t num_bytes) {
+  // Grow as much as possible within the mspace.
+  size_t max_allowed = maximum_size_;
+  mspace_set_max_allowed_footprint(mspace_, max_allowed);
+  // Try the allocation.
+  void* ptr = AllocWithoutGrowth(num_bytes);
+  // Shrink back down as small as possible.
+  size_t footprint = mspace_footprint(mspace_);
+  mspace_set_max_allowed_footprint(mspace_, footprint);
+  // Return the new allocation or NULL.
+  return reinterpret_cast<Object*>(ptr);
+}
+
+size_t Space::Free(void* ptr) {
+  DCHECK(ptr != NULL);
+  size_t num_bytes = mspace_usable_size(mspace_, ptr);
+  mspace_free(mspace_, ptr);
+  return num_bytes;
+}
+
+void Space::DontNeed(void* start, void* end, void* num_bytes) {
+  start = (void*)RoundUp((uintptr_t)start, 4096);
+  end = (void*)RoundDown((uintptr_t)end, 4096);
+  if (start >= end) {
+    return;
+  }
+  size_t length = reinterpret_cast<byte*>(end) - reinterpret_cast<byte*>(start);
+  int result = madvise(start, length, MADV_DONTNEED);
+  if (result == -1) {
+    PLOG(WARNING) << "madvise failed";
+  } else {
+    *reinterpret_cast<size_t*>(num_bytes) += length;
+  }
+}
+
+void Space::Trim() {
+  CHECK(mspace_ != NULL);
+  mspace_trim(mspace_, 0);
+  size_t num_bytes_released = 0;
+  mspace_walk_free_pages(mspace_, DontNeed, &num_bytes_released);
+}
+
+size_t Space::MaxAllowedFootprint() {
+  return mspace_max_allowed_footprint(mspace_);
+}
+
+void Space::Grow(size_t new_size) {
+}
+
+}  // namespace art
diff --git a/src/space.h b/src/space.h
new file mode 100644
index 0000000..ac69ba6
--- /dev/null
+++ b/src/space.h
@@ -0,0 +1,71 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#ifndef ART_SRC_SPACE_H_
+#define ART_SRC_SPACE_H_
+
+#include "src/globals.h"
+#include "src/macros.h"
+
+namespace art {
+
+class Object;
+
+// A space contains memory allocated for managed objects.
+class Space {
+ public:
+  static Space* Create(size_t startup_size, size_t maximum_size);
+
+  ~Space();
+
+  Object* AllocWithGrowth(size_t num_bytes);
+
+  Object* AllocWithoutGrowth(size_t num_bytes);
+
+  size_t Free(void* ptr);
+
+  void Trim();
+
+  size_t MaxAllowedFootprint();
+
+  void Grow(size_t num_bytes);
+
+  byte* GetBase() {
+    return base_;
+  }
+
+  size_t Size() {
+    return limit_ - base_;
+  }
+
+ private:
+  Space(size_t startup_size, size_t maximum_size) :
+      mspace_(NULL),
+      base_(NULL),
+      startup_size_(startup_size),
+      maximum_size_(maximum_size) {
+  }
+
+  bool Init();
+
+  void* CreateMallocSpace(void* base, size_t startup_size,
+                          size_t maximum_size);
+
+  static void DontNeed(void* start, void* end, void* num_bytes);
+
+  void* mspace_;
+
+  byte* base_;
+
+  byte* limit_;
+
+  size_t startup_size_;
+
+  size_t maximum_size_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Space);
+};
+
+}  // namespace art
+
+#endif  // ART_SRC_SPACE_H_
diff --git a/src/space_test.cc b/src/space_test.cc
new file mode 100644
index 0000000..db623eb
--- /dev/null
+++ b/src/space_test.cc
@@ -0,0 +1,68 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: cshapiro@google.com (Carl Shapiro)
+
+#include "src/space.h"
+
+#include "gtest/gtest.h"
+
+#include "src/globals.h"
+#include "src/scoped_ptr.h"
+
+namespace art {
+
+TEST(SpaceTest, Init) {
+  {
+    // Less than
+    scoped_ptr<Space> space(Space::Create(16 * MB, 32 * MB));
+    EXPECT_TRUE(space != NULL);
+  }
+  {
+    // Equal to
+    scoped_ptr<Space> space(Space::Create(16 * MB, 16 * MB));
+    EXPECT_TRUE(space != NULL);
+  }
+  {
+    // Greater than
+    scoped_ptr<Space> space(Space::Create(32 * MB, 16 * MB));
+    EXPECT_TRUE(space == NULL);
+  }
+}
+
+TEST(SpaceTest, AllocAndFree) {
+  scoped_ptr<Space> space(Space::Create(4 * MB, 16 * MB));
+  ASSERT_TRUE(space != NULL);
+
+  // Succeeds, fits without adjusting the max allowed footprint.
+  void* ptr1 = space->AllocWithoutGrowth(1 * MB);
+  EXPECT_TRUE(ptr1 != NULL);
+
+  // Fails, requires a higher allowed footprint.
+  void* ptr2 = space->AllocWithoutGrowth(8 * MB);
+  EXPECT_TRUE(ptr2 == NULL);
+
+  // Succeeds, adjusts the footprint.
+  void* ptr3 = space->AllocWithGrowth(8 * MB);
+  EXPECT_TRUE(ptr3 != NULL);
+
+  // Fails, requires a higher allowed footprint.
+  void* ptr4 = space->AllocWithoutGrowth(8 * MB);
+  EXPECT_FALSE(ptr4 != NULL);
+
+  // Also fails, requires a higher allowed footprint.
+  void* ptr5 = space->AllocWithGrowth(8 * MB);
+  EXPECT_FALSE(ptr5 != NULL);
+
+  // Release some memory.
+  size_t free3 = space->Free(ptr3);
+  EXPECT_LE(8U * MB, free3);
+
+  // Succeeds, now that memory has been freed.
+  void* ptr6 = space->AllocWithGrowth(9 * MB);
+  EXPECT_TRUE(ptr6 != NULL);
+
+  // Final clean up.
+  size_t free1 = space->Free(ptr1);
+  EXPECT_LE(1U * MB, free1);
+}
+
+}  // namespace art
diff --git a/src/thread.h b/src/thread.h
index 3f962d5..3c6e64b 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -8,17 +8,16 @@
 #include <list>
 
 #include "src/globals.h"
-#include "src/heap.h"
 #include "src/jni_internal.h"
 #include "src/logging.h"
 #include "src/macros.h"
+#include "src/offsets.h"
 #include "src/runtime.h"
 
 #include "jni.h"
 
 namespace art {
 
-class Heap;
 class Object;
 class Runtime;
 class StackHandleBlock;
@@ -162,6 +161,10 @@
 
   static bool Init();
 
+  Runtime* GetRuntime() const {
+    return runtime_;
+  }
+
   State GetState() {
     return state_;
   }
@@ -175,10 +178,6 @@
     return ThreadOffset(OFFSETOF_MEMBER(Thread, state_));
   }
 
-  Heap* GetHeap() {
-    return heap_;
-  }
-
   // JNI methods
   JniEnvironment* GetJniEnv() const {
     return jni_env_;
@@ -205,23 +204,18 @@
 
  private:
   Thread() :
-    thread_id_(1234), top_shb_(NULL), exception_(NULL) {
+    id_(1234), top_shb_(NULL), exception_(NULL) {
     jni_env_ = new JniEnvironment();
   }
+
   ~Thread() {
     delete jni_env_;
   }
 
   void InitCpu();
 
-  // Initialized to "this". On certain architectures (such as x86) reading
-  // off of Thread::Current is easy but getting the address of Thread::Current
-  // is hard. This field can be read off of Thread::Current to give the address.
-  Thread* self_;
-
-  uint32_t thread_id_;
-
-  Heap* heap_;
+  // Managed thread id.
+  uint32_t id_;
 
   // Top of linked list of stack handle blocks or NULL for none
   StackHandleBlock* top_shb_;
@@ -231,17 +225,29 @@
 
   State state_;
 
-  uint32_t id_;
-
+  // Native (kernel) thread id.
   pid_t native_id_;
 
+  // Native thread handle.
   pthread_t handle_;
 
+  // Initialized to "this". On certain architectures (such as x86) reading
+  // off of Thread::Current is easy but getting the address of Thread::Current
+  // is hard. This field can be read off of Thread::Current to give the address.
+  Thread* self_;
+
+  Runtime* runtime_;
+
+  // The pending exception or NULL.
   Object* exception_;
 
+  // The inclusive base of the control stack.
   byte* stack_base_;
+
+  // The exclusive limit of the control stack.
   byte* stack_limit_;
 
+  // TLS key used to retrieve the VM thread object.
   static pthread_key_t pthread_key_self_;
 
   DISALLOW_COPY_AND_ASSIGN(Thread);
diff --git a/src/thread_x86.cc b/src/thread_x86.cc
index 14cb2b2..718e9b8 100644
--- a/src/thread_x86.cc
+++ b/src/thread_x86.cc
@@ -47,12 +47,11 @@
   // Allow easy indirection back to Thread*
   self_ = this;
   // Sanity check reads from FS goes to this Thread*
-  CHECK_EQ(0, OFFSETOF_MEMBER(Thread, self_));
   Thread* self_check;
   // TODO: use our assembler to generate code
-  asm("movl %%fs:0, %0"
+  asm("movl %%fs:(%1), %0"
       : "=r"(self_check)  // output
-      :    // input
+      : "r"(OFFSETOF_MEMBER(Thread, self_))  // input
       :);  // clobber
   CHECK_EQ(self_check, this);
 }