mirror of
https://gitlab.winehq.org/wine/wine-gecko.git
synced 2024-09-13 09:24:08 -07:00
103 lines
3.2 KiB
C++
103 lines
3.2 KiB
C++
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
|
|
* You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#ifndef SeekableZStream_h
|
|
#define SeekableZStream_h
|
|
|
|
#include "Zip.h"
|
|
|
|
/**
|
|
* Seekable compressed stream are created by splitting the original
|
|
* decompressed data in small chunks and compress these chunks
|
|
* individually.
|
|
*
|
|
* The seekable compressed file format consists in a header defined below,
|
|
* followed by a table of 32-bits words containing the offsets for each
|
|
* individual compressed chunk, then followed by the compressed chunks.
|
|
*/
|
|
|
|
#pragma pack(1)
|
|
struct SeekableZStreamHeader: public Zip::SignedEntity<SeekableZStreamHeader>
|
|
{
|
|
SeekableZStreamHeader()
|
|
: Zip::SignedEntity<SeekableZStreamHeader>(magic)
|
|
, totalSize(0), chunkSize(0), nChunks(0), lastChunkSize(0) { }
|
|
|
|
/* Reuse Zip::SignedEntity to handle the magic number used in the Seekable
|
|
* ZStream file format. The magic number is "SeZz". */
|
|
static const uint32_t magic = 0x7a5a6553;
|
|
|
|
/* Total size of the stream, including the 4 magic bytes. */
|
|
le_uint32 totalSize;
|
|
|
|
/* Chunk size */
|
|
le_uint32 chunkSize;
|
|
|
|
/* Number of chunks */
|
|
le_uint32 nChunks;
|
|
|
|
/* Size of last chunk (> 0, <= Chunk size) */
|
|
le_uint32 lastChunkSize;
|
|
};
|
|
#pragma pack()
|
|
|
|
MOZ_STATIC_ASSERT(sizeof(SeekableZStreamHeader) == 5 * 4,
|
|
"SeekableZStreamHeader should be 5 32-bits words");
|
|
|
|
/**
|
|
* Helper class used to decompress Seekable ZStreams.
|
|
*/
|
|
class SeekableZStream {
|
|
public:
|
|
/* Initialize from the given buffer. Returns whether initialization
|
|
* succeeded (true) or failed (false). */
|
|
bool Init(const void *buf);
|
|
|
|
/* Decompresses starting from the given chunk. The decompressed data is
|
|
* stored at the given location. The given length, in bytes, indicates
|
|
* how much data to decompress. If length is 0, then exactly one chunk
|
|
* is decompressed.
|
|
* Returns whether decompression succeeded (true) or failed (false). */
|
|
bool Decompress(void *where, size_t chunk, size_t length = 0);
|
|
|
|
/* Decompresses the given chunk at the given address. If a length is given,
|
|
* only decompresses that amount of data instead of the entire chunk.
|
|
* Returns whether decompression succeeded (true) or failed (false). */
|
|
bool DecompressChunk(void *where, size_t chunk, size_t length = 0);
|
|
|
|
/* Returns the uncompressed size of the complete zstream */
|
|
const size_t GetUncompressedSize() const
|
|
{
|
|
return (offsetTable.numElements() - 1) * chunkSize + lastChunkSize;
|
|
}
|
|
|
|
/* Returns the chunk size of the given chunk */
|
|
const size_t GetChunkSize(size_t chunk = 0) const {
|
|
return (chunk == offsetTable.numElements() - 1) ? lastChunkSize : chunkSize;
|
|
}
|
|
|
|
/* Returns the number of chunks */
|
|
const size_t GetChunksNum() const {
|
|
return offsetTable.numElements();
|
|
}
|
|
|
|
private:
|
|
/* RAW Seekable SZtream buffer */
|
|
const unsigned char *buffer;
|
|
|
|
/* Total size of the stream, including the 4 magic bytes. */
|
|
uint32_t totalSize;
|
|
|
|
/* Chunk size */
|
|
uint32_t chunkSize;
|
|
|
|
/* Size of last chunk (> 0, <= Chunk size) */
|
|
uint32_t lastChunkSize;
|
|
|
|
/* Offsets table */
|
|
Array<le_uint32> offsetTable;
|
|
};
|
|
|
|
#endif /* SeekableZStream_h */
|