diff --git a/include/utils/SortedVector.h b/include/utils/SortedVector.h
index c8a6153..8beec57 100644
--- a/include/utils/SortedVector.h
+++ b/include/utils/SortedVector.h
@@ -141,8 +141,7 @@
     : SortedVectorImpl(sizeof(TYPE),
                 ((traits<TYPE>::has_trivial_ctor   ? HAS_TRIVIAL_CTOR   : 0)
                 |(traits<TYPE>::has_trivial_dtor   ? HAS_TRIVIAL_DTOR   : 0)
-                |(traits<TYPE>::has_trivial_copy   ? HAS_TRIVIAL_COPY   : 0)
-                |(traits<TYPE>::has_trivial_assign ? HAS_TRIVIAL_ASSIGN : 0))
+                |(traits<TYPE>::has_trivial_copy   ? HAS_TRIVIAL_COPY   : 0))
                 )
 {
 }
diff --git a/include/utils/TypeHelpers.h b/include/utils/TypeHelpers.h
index c04c37f..2ff2749 100644
--- a/include/utils/TypeHelpers.h
+++ b/include/utils/TypeHelpers.h
@@ -29,35 +29,39 @@
 /*
  * Types traits
  */
-    
-template <typename T> struct trait_trivial_ctor  { enum { value = false }; };
-template <typename T> struct trait_trivial_dtor  { enum { value = false }; };
-template <typename T> struct trait_trivial_copy  { enum { value = false }; };
-template <typename T> struct trait_trivial_assign{ enum { value = false }; };
 
-template <typename T> struct trait_pointer     { enum { value = false }; };    
-template <typename T> struct trait_pointer<T*> { enum { value = true }; };
+template <typename T> struct trait_trivial_ctor { enum { value = false }; };
+template <typename T> struct trait_trivial_dtor { enum { value = false }; };
+template <typename T> struct trait_trivial_copy { enum { value = false }; };
+template <typename T> struct trait_trivial_move { enum { value = false }; };
+template <typename T> struct trait_pointer      { enum { value = false }; };    
+template <typename T> struct trait_pointer<T*>  { enum { value = true }; };
 
-#define ANDROID_BASIC_TYPES_TRAITS( T )                                       \
-    template<> struct trait_trivial_ctor< T >  { enum { value = true }; };    \
-    template<> struct trait_trivial_dtor< T >  { enum { value = true }; };    \
-    template<> struct trait_trivial_copy< T >  { enum { value = true }; };    \
-    template<> struct trait_trivial_assign< T >{ enum { value = true }; }; 
+// sp<> can be trivially moved
+template <typename T> class sp;
+template <typename T> struct trait_trivial_move< sp<T> >{
+    enum { value = true }; 
+};
 
-#define ANDROID_TYPE_TRAITS( T, ctor, dtor, copy, assign )                    \
-    template<> struct trait_trivial_ctor< T >  { enum { value = ctor }; };    \
-    template<> struct trait_trivial_dtor< T >  { enum { value = dtor }; };    \
-    template<> struct trait_trivial_copy< T >  { enum { value = copy }; };    \
-    template<> struct trait_trivial_assign< T >{ enum { value = assign }; }; 
+// wp<> can be trivially moved
+template <typename T> class wp;
+template <typename T> struct trait_trivial_move< wp<T> >{ 
+    enum { value = true }; 
+};
 
 template <typename TYPE>
 struct traits {
     enum {
+        // whether this type is a pointer
         is_pointer          = trait_pointer<TYPE>::value,
+        // whether this type's constructor is a no-op
         has_trivial_ctor    = is_pointer || trait_trivial_ctor<TYPE>::value,
+        // whether this type's destructor is a no-op
         has_trivial_dtor    = is_pointer || trait_trivial_dtor<TYPE>::value,
+        // whether this type type can be copy-constructed with memcpy
         has_trivial_copy    = is_pointer || trait_trivial_copy<TYPE>::value,
-        has_trivial_assign  = is_pointer || trait_trivial_assign<TYPE>::value   
+        // whether this type can be moved with memmove
+        has_trivial_move    = is_pointer || trait_trivial_move<TYPE>::value
     };
 };
 
@@ -65,37 +69,47 @@
 struct aggregate_traits {
     enum {
         is_pointer          = false,
-        has_trivial_ctor    = traits<T>::has_trivial_ctor && traits<U>::has_trivial_ctor,
-        has_trivial_dtor    = traits<T>::has_trivial_dtor && traits<U>::has_trivial_dtor,
-        has_trivial_copy    = traits<T>::has_trivial_copy && traits<U>::has_trivial_copy,
-        has_trivial_assign  = traits<T>::has_trivial_assign && traits<U>::has_trivial_assign
+        has_trivial_ctor    = 
+            traits<T>::has_trivial_ctor && traits<U>::has_trivial_ctor,
+        has_trivial_dtor    = 
+            traits<T>::has_trivial_dtor && traits<U>::has_trivial_dtor,
+        has_trivial_copy    = 
+            traits<T>::has_trivial_copy && traits<U>::has_trivial_copy,
+        has_trivial_move    = 
+            traits<T>::has_trivial_move && traits<U>::has_trivial_move
     };
 };
 
+#define ANDROID_BASIC_TYPES_TRAITS( T )                                     \
+    template<> struct trait_trivial_ctor< T >   { enum { value = true }; }; \
+    template<> struct trait_trivial_dtor< T >   { enum { value = true }; }; \
+    template<> struct trait_trivial_copy< T >   { enum { value = true }; }; \
+    template<> struct trait_trivial_move< T >   { enum { value = true }; };
+
 // ---------------------------------------------------------------------------
 
 /*
  * basic types traits
  */
- 
-ANDROID_BASIC_TYPES_TRAITS( void );
-ANDROID_BASIC_TYPES_TRAITS( bool );
-ANDROID_BASIC_TYPES_TRAITS( char );
-ANDROID_BASIC_TYPES_TRAITS( unsigned char );
-ANDROID_BASIC_TYPES_TRAITS( short );
-ANDROID_BASIC_TYPES_TRAITS( unsigned short );
-ANDROID_BASIC_TYPES_TRAITS( int );
-ANDROID_BASIC_TYPES_TRAITS( unsigned int );
-ANDROID_BASIC_TYPES_TRAITS( long );
-ANDROID_BASIC_TYPES_TRAITS( unsigned long );
-ANDROID_BASIC_TYPES_TRAITS( long long );
-ANDROID_BASIC_TYPES_TRAITS( unsigned long long );
-ANDROID_BASIC_TYPES_TRAITS( float );
-ANDROID_BASIC_TYPES_TRAITS( double );
+
+ANDROID_BASIC_TYPES_TRAITS( void )
+ANDROID_BASIC_TYPES_TRAITS( bool )
+ANDROID_BASIC_TYPES_TRAITS( char )
+ANDROID_BASIC_TYPES_TRAITS( unsigned char )
+ANDROID_BASIC_TYPES_TRAITS( short )
+ANDROID_BASIC_TYPES_TRAITS( unsigned short )
+ANDROID_BASIC_TYPES_TRAITS( int )
+ANDROID_BASIC_TYPES_TRAITS( unsigned int )
+ANDROID_BASIC_TYPES_TRAITS( long )
+ANDROID_BASIC_TYPES_TRAITS( unsigned long )
+ANDROID_BASIC_TYPES_TRAITS( long long )
+ANDROID_BASIC_TYPES_TRAITS( unsigned long long )
+ANDROID_BASIC_TYPES_TRAITS( float )
+ANDROID_BASIC_TYPES_TRAITS( double )
 
 // ---------------------------------------------------------------------------
 
-    
+
 /*
  * compare and order types
  */
@@ -111,9 +125,9 @@
 }
 
 /*
- * create, destroy, copy and assign types...
+ * create, destroy, copy and move types...
  */
- 
+
 template<typename TYPE> inline
 void construct_type(TYPE* p, size_t n) {
     if (!traits<TYPE>::has_trivial_ctor) {
@@ -146,17 +160,6 @@
 }
 
 template<typename TYPE> inline
-void assign_type(TYPE* d, const TYPE* s, size_t n) {
-    if (!traits<TYPE>::has_trivial_assign) {
-        while (n--) {
-            *d++ = *s++;
-        }
-    } else {
-        memcpy(d,s,n*sizeof(TYPE));
-    }
-}
-
-template<typename TYPE> inline
 void splat_type(TYPE* where, const TYPE* what, size_t n) {
     if (!traits<TYPE>::has_trivial_copy) {
         while (n--) {
@@ -164,15 +167,19 @@
             where++;
         }
     } else {
-         while (n--) {
-             *where++ = *what;
+        while (n--) {
+            *where++ = *what;
         }
     }
 }
 
 template<typename TYPE> inline
 void move_forward_type(TYPE* d, const TYPE* s, size_t n = 1) {
-    if (!traits<TYPE>::has_trivial_copy || !traits<TYPE>::has_trivial_dtor) {
+    if ((traits<TYPE>::has_trivial_dtor && traits<TYPE>::has_trivial_copy) 
+            || traits<TYPE>::has_trivial_move) 
+    {
+        memmove(d,s,n*sizeof(TYPE));
+    } else {
         d += n;
         s += n;
         while (n--) {
@@ -180,35 +187,37 @@
             if (!traits<TYPE>::has_trivial_copy) {
                 new(d) TYPE(*s);
             } else {
-                *d = *s;
+                *d = *s;   
             }
             if (!traits<TYPE>::has_trivial_dtor) {
                 s->~TYPE();
             }
         }
-    } else {
-        memmove(d,s,n*sizeof(TYPE));
     }
 }
 
 template<typename TYPE> inline
 void move_backward_type(TYPE* d, const TYPE* s, size_t n = 1) {
-    if (!traits<TYPE>::has_trivial_copy || !traits<TYPE>::has_trivial_dtor) {
+    if ((traits<TYPE>::has_trivial_dtor && traits<TYPE>::has_trivial_copy) 
+            || traits<TYPE>::has_trivial_move) 
+    {
+        memmove(d,s,n*sizeof(TYPE));
+    } else {
         while (n--) {
             if (!traits<TYPE>::has_trivial_copy) {
                 new(d) TYPE(*s);
             } else {
-                *d = *s;
+                *d = *s;   
             }
             if (!traits<TYPE>::has_trivial_dtor) {
                 s->~TYPE();
             }
             d++, s++;
         }
-    } else {
-        memmove(d,s,n*sizeof(TYPE));
     }
 }
+
+
 // ---------------------------------------------------------------------------
 
 /*
@@ -242,8 +251,8 @@
 { enum { value = aggregate_traits<K,V>::has_trivial_copy }; };
 template<> 
 template <typename K, typename V>
-struct trait_trivial_assign< key_value_pair_t<K, V> >
-{ enum { value = aggregate_traits<K,V>::has_trivial_assign};};
+struct trait_trivial_move< key_value_pair_t<K, V> >
+{ enum { value = aggregate_traits<K,V>::has_trivial_move }; };
 
 // ---------------------------------------------------------------------------
 
diff --git a/include/utils/Vector.h b/include/utils/Vector.h
index be365d8..ad59fd6 100644
--- a/include/utils/Vector.h
+++ b/include/utils/Vector.h
@@ -175,8 +175,7 @@
     : VectorImpl(sizeof(TYPE),
                 ((traits<TYPE>::has_trivial_ctor   ? HAS_TRIVIAL_CTOR   : 0)
                 |(traits<TYPE>::has_trivial_dtor   ? HAS_TRIVIAL_DTOR   : 0)
-                |(traits<TYPE>::has_trivial_copy   ? HAS_TRIVIAL_COPY   : 0)
-                |(traits<TYPE>::has_trivial_assign ? HAS_TRIVIAL_ASSIGN : 0))
+                |(traits<TYPE>::has_trivial_copy   ? HAS_TRIVIAL_COPY   : 0))
                 )
 {
 }
diff --git a/include/utils/VectorImpl.h b/include/utils/VectorImpl.h
index 2525229..49b03f1 100644
--- a/include/utils/VectorImpl.h
+++ b/include/utils/VectorImpl.h
@@ -44,7 +44,6 @@
         HAS_TRIVIAL_CTOR    = 0x00000001,
         HAS_TRIVIAL_DTOR    = 0x00000002,
         HAS_TRIVIAL_COPY    = 0x00000004,
-        HAS_TRIVIAL_ASSIGN  = 0x00000008
     };
 
                             VectorImpl(size_t itemSize, uint32_t flags);