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/*
* shrink_inmem.c - in-memory compression implementation
*
* Copyright (C) 2019 Emmanuel Marty
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
/*
* Uses the libdivsufsort library Copyright (c) 2003-2008 Yuta Mori
*
* Inspired by LZ4 by Yann Collet. https://github.com/lz4/lz4
* With help, ideas, optimizations and speed measurements by spke <zxintrospec@gmail.com>
* With ideas from Lizard by Przemyslaw Skibinski and Yann Collet. https://github.com/inikep/lizard
* Also with ideas from smallz4 by Stephan Brumme. https://create.stephan-brumme.com/smallz4/
*
*/
#include <stdlib.h>
#include <string.h>
#include "shrink_inmem.h"
#include "shrink_context.h"
#include "frame.h"
#include "format.h"
#include "lib.h"
/**
* Get maximum compressed size of input(source) data
*
* @param nInputSize input(source) size in bytes
*
* @return maximum compressed size
*/
size_t lzsa_get_max_compressed_size_inmem(size_t nInputSize) {
return lzsa_get_header_size() + ((nInputSize + (BLOCK_SIZE - 1)) >> 16) * lzsa_get_frame_size() + nInputSize + lzsa_get_frame_size() /* footer */;
}
/**
* Compress memory
*
* @param pInputData pointer to input(source) data to compress
* @param pOutBuffer buffer for compressed data
* @param nInputSize input(source) size in bytes
* @param nMaxOutBufferSize maximum capacity of compression buffer
* @param nFlags compression flags (LZSA_FLAG_xxx)
* @param nMinMatchSize minimum match size
* @param nFormatVersion version of format to use (1-2)
*
* @return actual compressed size, or -1 for error
*/
size_t lzsa_compress_inmem(unsigned char *pInputData, unsigned char *pOutBuffer, size_t nInputSize, size_t nMaxOutBufferSize,
const unsigned int nFlags, const int nMinMatchSize, const int nFormatVersion) {
lzsa_compressor compressor;
size_t nOriginalSize = 0;
size_t nCompressedSize = 0L;
int nResult;
int nError = 0;
nResult = lzsa_compressor_init(&compressor, BLOCK_SIZE * 2, nMinMatchSize, nFormatVersion, nFlags);
if (nResult != 0) {
return -1;
}
if ((nFlags & LZSA_FLAG_RAW_BLOCK) == 0) {
int nHeaderSize = lzsa_encode_header(pOutBuffer, (int)nMaxOutBufferSize, nFormatVersion);
if (nHeaderSize < 0)
nError = LZSA_ERROR_COMPRESSION;
else {
nCompressedSize += nHeaderSize;
}
}
int nPreviousBlockSize = 0;
int nNumBlocks = 0;
while (nOriginalSize < nInputSize && !nError) {
int nInDataSize;
nInDataSize = (int)(nInputSize - nOriginalSize);
if (nInDataSize > BLOCK_SIZE)
nInDataSize = BLOCK_SIZE;
if (nInDataSize > 0) {
if ((nFlags & LZSA_FLAG_RAW_BLOCK) != 0 && nNumBlocks) {
nError = LZSA_ERROR_RAW_TOOLARGE;
break;
}
int nOutDataSize;
int nOutDataEnd = (int)(nMaxOutBufferSize - (lzsa_get_frame_size() + nCompressedSize + lzsa_get_frame_size() /* footer */));
int nFrameSize = lzsa_get_frame_size();
if ((nFlags & LZSA_FLAG_RAW_BLOCK) != 0) {
nFrameSize = 0;
nOutDataEnd = (int)(nMaxOutBufferSize - nCompressedSize);
}
if (nOutDataEnd > BLOCK_SIZE)
nOutDataEnd = BLOCK_SIZE;
nOutDataSize = lzsa_compressor_shrink_block(&compressor, pInputData + nOriginalSize - nPreviousBlockSize, nPreviousBlockSize, nInDataSize, pOutBuffer + nFrameSize + nCompressedSize, nOutDataEnd);
if (nOutDataSize >= 0) {
/* Write compressed block */
if ((nFlags & LZSA_FLAG_RAW_BLOCK) == 0) {
int nBlockheaderSize = lzsa_encode_compressed_block_frame(pOutBuffer + nCompressedSize, (int)(nMaxOutBufferSize - nCompressedSize), nOutDataSize);
if (nBlockheaderSize < 0)
nError = LZSA_ERROR_COMPRESSION;
else {
nCompressedSize += nBlockheaderSize;
}
}
if (!nError) {
nOriginalSize += nInDataSize;
nCompressedSize += nOutDataSize;
}
}
else {
/* Write uncompressible, literal block */
if ((nFlags & LZSA_FLAG_RAW_BLOCK) != 0) {
nError = LZSA_ERROR_RAW_UNCOMPRESSED;
break;
}
int nBlockheaderSize = lzsa_encode_uncompressed_block_frame(pOutBuffer + nCompressedSize, (int)(nMaxOutBufferSize - nCompressedSize), nInDataSize);
if (nBlockheaderSize < 0)
nError = LZSA_ERROR_COMPRESSION;
else {
if ((size_t)nInDataSize > (nMaxOutBufferSize - (nCompressedSize + nBlockheaderSize)))
nError = LZSA_ERROR_DST;
else {
memcpy(pOutBuffer + nBlockheaderSize + nCompressedSize, pInputData + nOriginalSize, nInDataSize);
nOriginalSize += nInDataSize;
nCompressedSize += nBlockheaderSize + nInDataSize;
}
}
}
nPreviousBlockSize = nInDataSize;
nNumBlocks++;
}
}
if (!nError) {
int nFooterSize;
if ((nFlags & LZSA_FLAG_RAW_BLOCK) != 0) {
nFooterSize = 0;
}
else {
nFooterSize = lzsa_encode_footer_frame(pOutBuffer + nCompressedSize, (int)(nMaxOutBufferSize - nCompressedSize));
if (nFooterSize < 0)
nError = LZSA_ERROR_COMPRESSION;
}
nCompressedSize += nFooterSize;
}
lzsa_compressor_destroy(&compressor);
if (nError) {
return -1;
}
else {
return nCompressedSize;
}
}
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