Initial Contribution
diff --git a/include/utils/Asset.h b/include/utils/Asset.h
new file mode 100644
index 0000000..d8351f5
--- /dev/null
+++ b/include/utils/Asset.h
@@ -0,0 +1,311 @@
+/*
+ * 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.
+ */
+
+//
+// Class providing access to a read-only asset. Asset objects are NOT
+// thread-safe, and should not be shared across threads.
+//
+#ifndef __LIBS_ASSET_H
+#define __LIBS_ASSET_H
+
+#include <stdio.h>
+#include <sys/types.h>
+#include "FileMap.h"
+#include "String8.h"
+#include "Errors.h"
+
+namespace android {
+
+/*
+ * Instances of this class provide read-only operations on a byte stream.
+ *
+ * Access may be optimized for streaming, random, or whole buffer modes. All
+ * operations are supported regardless of how the file was opened, but some
+ * things will be less efficient. [pass that in??]
+ *
+ * "Asset" is the base class for all types of assets. The classes below
+ * provide most of the implementation. The AssetManager uses one of the
+ * static "create" functions defined here to create a new instance.
+ */
+class Asset {
+public:
+ virtual ~Asset(void);
+
+ static int32_t getGlobalCount();
+
+ /* used when opening an asset */
+ typedef enum AccessMode {
+ ACCESS_UNKNOWN = 0,
+
+ /* read chunks, and seek forward and backward */
+ ACCESS_RANDOM,
+
+ /* read sequentially, with an occasional forward seek */
+ ACCESS_STREAMING,
+
+ /* caller plans to ask for a read-only buffer with all data */
+ ACCESS_BUFFER,
+ } AccessMode;
+
+ enum {
+ /* data larger than this does not get uncompressed into a buffer */
+ UNCOMPRESS_DATA_MAX = 1 * 1024 * 1024
+ };
+
+ /*
+ * Read data from the current offset. Returns the actual number of
+ * bytes read, 0 on EOF, or -1 on error.
+ */
+ virtual ssize_t read(void* buf, size_t count) = 0;
+
+ /*
+ * Seek to the specified offset. "whence" uses the same values as
+ * lseek/fseek. Returns the new position on success, or (off_t) -1
+ * on failure.
+ */
+ virtual off_t seek(off_t offset, int whence) = 0;
+
+ /*
+ * Close the asset, freeing all associated resources.
+ */
+ virtual void close(void) = 0;
+
+ /*
+ * Get a pointer to a buffer with the entire contents of the file.
+ */
+ virtual const void* getBuffer(bool wordAligned) = 0;
+
+ /*
+ * Get the total amount of data that can be read.
+ */
+ virtual off_t getLength(void) const = 0;
+
+ /*
+ * Get the total amount of data that can be read from the current position.
+ */
+ virtual off_t getRemainingLength(void) const = 0;
+
+ /*
+ * Open a new file descriptor that can be used to read this asset.
+ * Returns -1 if you can not use the file descriptor (for example if the
+ * asset is compressed).
+ */
+ virtual int openFileDescriptor(off_t* outStart, off_t* outLength) const = 0;
+
+ /*
+ * Get a string identifying the asset's source. This might be a full
+ * path, it might be a colon-separated list of identifiers.
+ *
+ * This is NOT intended to be used for anything except debug output.
+ * DO NOT try to parse this or use it to open a file.
+ */
+ const char* getAssetSource(void) const { return mAssetSource.string(); }
+
+protected:
+ Asset(void); // constructor; only invoked indirectly
+
+ /* handle common seek() housekeeping */
+ off_t handleSeek(off_t offset, int whence, off_t curPosn, off_t maxPosn);
+
+ /* set the asset source string */
+ void setAssetSource(const String8& path) { mAssetSource = path; }
+
+ AccessMode getAccessMode(void) const { return mAccessMode; }
+
+private:
+ /* these operations are not implemented */
+ Asset(const Asset& src);
+ Asset& operator=(const Asset& src);
+
+ /* AssetManager needs access to our "create" functions */
+ friend class AssetManager;
+
+ /*
+ * Create the asset from a named file on disk.
+ */
+ static Asset* createFromFile(const char* fileName, AccessMode mode);
+
+ /*
+ * Create the asset from a named, compressed file on disk (e.g. ".gz").
+ */
+ static Asset* createFromCompressedFile(const char* fileName,
+ AccessMode mode);
+
+#if 0
+ /*
+ * Create the asset from a segment of an open file. This will fail
+ * if "offset" and "length" don't fit within the bounds of the file.
+ *
+ * The asset takes ownership of the file descriptor.
+ */
+ static Asset* createFromFileSegment(int fd, off_t offset, size_t length,
+ AccessMode mode);
+
+ /*
+ * Create from compressed data. "fd" should be seeked to the start of
+ * the compressed data. This could be inside a gzip file or part of a
+ * Zip archive.
+ *
+ * The asset takes ownership of the file descriptor.
+ *
+ * This may not verify the validity of the compressed data until first
+ * use.
+ */
+ static Asset* createFromCompressedData(int fd, off_t offset,
+ int compressionMethod, size_t compressedLength,
+ size_t uncompressedLength, AccessMode mode);
+#endif
+
+ /*
+ * Create the asset from a memory-mapped file segment.
+ *
+ * The asset takes ownership of the FileMap.
+ */
+ static Asset* createFromUncompressedMap(FileMap* dataMap, AccessMode mode);
+
+ /*
+ * Create the asset from a memory-mapped file segment with compressed
+ * data. "method" is a Zip archive compression method constant.
+ *
+ * The asset takes ownership of the FileMap.
+ */
+ static Asset* createFromCompressedMap(FileMap* dataMap, int method,
+ size_t uncompressedLen, AccessMode mode);
+
+
+ /*
+ * Create from a reference-counted chunk of shared memory.
+ */
+ // TODO
+
+ AccessMode mAccessMode; // how the asset was opened
+ String8 mAssetSource; // debug string
+};
+
+
+/*
+ * ===========================================================================
+ *
+ * Innards follow. Do not use these classes directly.
+ */
+
+/*
+ * An asset based on an uncompressed file on disk. It may encompass the
+ * entire file or just a piece of it. Access is through fread/fseek.
+ */
+class _FileAsset : public Asset {
+public:
+ _FileAsset(void);
+ virtual ~_FileAsset(void);
+
+ /*
+ * Use a piece of an already-open file.
+ *
+ * On success, the object takes ownership of "fd".
+ */
+ status_t openChunk(const char* fileName, int fd, off_t offset, size_t length);
+
+ /*
+ * Use a memory-mapped region.
+ *
+ * On success, the object takes ownership of "dataMap".
+ */
+ status_t openChunk(FileMap* dataMap);
+
+ /*
+ * Standard Asset interfaces.
+ */
+ virtual ssize_t read(void* buf, size_t count);
+ virtual off_t seek(off_t offset, int whence);
+ virtual void close(void);
+ virtual const void* getBuffer(bool wordAligned);
+ virtual off_t getLength(void) const { return mLength; }
+ virtual off_t getRemainingLength(void) const { return mLength-mOffset; }
+ virtual int openFileDescriptor(off_t* outStart, off_t* outLength) const;
+
+private:
+ off_t mStart; // absolute file offset of start of chunk
+ off_t mLength; // length of the chunk
+ off_t mOffset; // current local offset, 0 == mStart
+ FILE* mFp; // for read/seek
+ char* mFileName; // for opening
+
+ /*
+ * To support getBuffer() we either need to read the entire thing into
+ * a buffer or memory-map it. For small files it's probably best to
+ * just read them in.
+ */
+ enum { kReadVsMapThreshold = 4096 };
+
+ FileMap* mMap; // for memory map
+ unsigned char* mBuf; // for read
+
+ const void* ensureAlignment(FileMap* map);
+};
+
+
+/*
+ * An asset based on compressed data in a file.
+ */
+class _CompressedAsset : public Asset {
+public:
+ _CompressedAsset(void);
+ virtual ~_CompressedAsset(void);
+
+ /*
+ * Use a piece of an already-open file.
+ *
+ * On success, the object takes ownership of "fd".
+ */
+ status_t openChunk(int fd, off_t offset, int compressionMethod,
+ size_t uncompressedLen, size_t compressedLen);
+
+ /*
+ * Use a memory-mapped region.
+ *
+ * On success, the object takes ownership of "fd".
+ */
+ status_t openChunk(FileMap* dataMap, int compressionMethod,
+ size_t uncompressedLen);
+
+ /*
+ * Standard Asset interfaces.
+ */
+ virtual ssize_t read(void* buf, size_t count);
+ virtual off_t seek(off_t offset, int whence);
+ virtual void close(void);
+ virtual const void* getBuffer(bool wordAligned);
+ virtual off_t getLength(void) const { return mUncompressedLen; }
+ virtual off_t getRemainingLength(void) const { return mUncompressedLen-mOffset; }
+ virtual int openFileDescriptor(off_t* outStart, off_t* outLength) const { return -1; }
+
+private:
+ off_t mStart; // offset to start of compressed data
+ off_t mCompressedLen; // length of the compressed data
+ off_t mUncompressedLen; // length of the uncompressed data
+ off_t mOffset; // current offset, 0 == start of uncomp data
+
+ FileMap* mMap; // for memory-mapped input
+ int mFd; // for file input
+
+ unsigned char* mBuf; // for getBuffer()
+};
+
+// need: shared mmap version?
+
+}; // namespace android
+
+#endif // __LIBS_ASSET_H