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/*
* shrink_context.c - compression context 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_context.h"
#include "shrink_block_v1.h"
#include "shrink_block_v2.h"
#include "format.h"
#include "matchfinder.h"
#include "lib.h"
/**
* Initialize compression context
*
* @param pCompressor compression context to initialize
* @param nMaxWindowSize maximum size of input data window (previously compressed bytes + bytes to compress)
* @param nMinMatchSize minimum match size (cannot be less than MIN_MATCH_SIZE)
* @param nFlags compression flags
*
* @return 0 for success, non-zero for failure
*/
int lzsa_compressor_init(lzsa_compressor *pCompressor, const int nMaxWindowSize, const int nMinMatchSize, const int nFormatVersion, const int nFlags) {
int nResult;
int nMinMatchSizeForFormat = (nFormatVersion == 1) ? MIN_MATCH_SIZE_V1 : MIN_MATCH_SIZE_V2;
int nMaxMinMatchForFormat = (nFormatVersion == 1) ? 5 : 3;
nResult = divsufsort_init(&pCompressor->divsufsort_context);
pCompressor->intervals = NULL;
pCompressor->pos_data = NULL;
pCompressor->open_intervals = NULL;
pCompressor->match = NULL;
pCompressor->best_match = NULL;
pCompressor->improved_match = NULL;
pCompressor->arrival = NULL;
pCompressor->rep_handled_mask = NULL;
pCompressor->first_offset_for_byte = NULL;
pCompressor->next_offset_for_pos = NULL;
pCompressor->min_match_size = nMinMatchSize;
if (pCompressor->min_match_size < nMinMatchSizeForFormat)
pCompressor->min_match_size = nMinMatchSizeForFormat;
else if (pCompressor->min_match_size > nMaxMinMatchForFormat)
pCompressor->min_match_size = nMaxMinMatchForFormat;
pCompressor->format_version = nFormatVersion;
pCompressor->flags = nFlags;
pCompressor->safe_dist = 0;
pCompressor->num_commands = 0;
memset(&pCompressor->stats, 0, sizeof(pCompressor->stats));
pCompressor->stats.min_literals = -1;
pCompressor->stats.min_match_len = -1;
pCompressor->stats.min_offset = -1;
pCompressor->stats.min_rle1_len = -1;
pCompressor->stats.min_rle2_len = -1;
if (!nResult) {
pCompressor->intervals = (unsigned int *)malloc(nMaxWindowSize * sizeof(unsigned int));
if (pCompressor->intervals) {
pCompressor->pos_data = (unsigned int *)malloc(nMaxWindowSize * sizeof(unsigned int));
if (pCompressor->pos_data) {
pCompressor->open_intervals = (unsigned int *)malloc((LCP_AND_TAG_MAX + 1) * sizeof(unsigned int));
if (pCompressor->open_intervals) {
pCompressor->arrival = (lzsa_arrival *)malloc(((BLOCK_SIZE + 1) << ARRIVALS_PER_POSITION_SHIFT) * sizeof(lzsa_arrival));
if (pCompressor->arrival) {
pCompressor->best_match = (lzsa_match *)malloc(BLOCK_SIZE * sizeof(lzsa_match));
if (pCompressor->best_match) {
pCompressor->improved_match = (lzsa_match *)malloc(BLOCK_SIZE * sizeof(lzsa_match));
if (pCompressor->improved_match) {
if (pCompressor->format_version == 2)
pCompressor->match = (lzsa_match *)malloc(BLOCK_SIZE * NMATCHES_PER_INDEX_V2 * sizeof(lzsa_match));
else
pCompressor->match = (lzsa_match *)malloc(BLOCK_SIZE * NMATCHES_PER_INDEX_V1 * sizeof(lzsa_match));
if (pCompressor->match) {
if (pCompressor->format_version == 2) {
pCompressor->rep_handled_mask = (char*)malloc(NARRIVALS_PER_POSITION_V2_BIG * ((LCP_MAX + 1) / 8) * sizeof(char));
if (pCompressor->rep_handled_mask) {
pCompressor->first_offset_for_byte = (int*)malloc(65536 * sizeof(int));
if (pCompressor->first_offset_for_byte) {
pCompressor->next_offset_for_pos = (int*)malloc(BLOCK_SIZE * sizeof(int));
if (pCompressor->next_offset_for_pos) {
return 0;
}
}
}
}
else {
return 0;
}
}
}
}
}
}
}
}
}
lzsa_compressor_destroy(pCompressor);
return 100;
}
/**
* Clean up compression context and free up any associated resources
*
* @param pCompressor compression context to clean up
*/
void lzsa_compressor_destroy(lzsa_compressor *pCompressor) {
divsufsort_destroy(&pCompressor->divsufsort_context);
if (pCompressor->next_offset_for_pos) {
free(pCompressor->next_offset_for_pos);
pCompressor->next_offset_for_pos = NULL;
}
if (pCompressor->first_offset_for_byte) {
free(pCompressor->first_offset_for_byte);
pCompressor->first_offset_for_byte = NULL;
}
if (pCompressor->rep_handled_mask) {
free(pCompressor->rep_handled_mask);
pCompressor->rep_handled_mask = NULL;
}
if (pCompressor->match) {
free(pCompressor->match);
pCompressor->match = NULL;
}
if (pCompressor->improved_match) {
free(pCompressor->improved_match);
pCompressor->improved_match = NULL;
}
if (pCompressor->arrival) {
free(pCompressor->arrival);
pCompressor->arrival = NULL;
}
if (pCompressor->best_match) {
free(pCompressor->best_match);
pCompressor->best_match = NULL;
}
if (pCompressor->open_intervals) {
free(pCompressor->open_intervals);
pCompressor->open_intervals = NULL;
}
if (pCompressor->pos_data) {
free(pCompressor->pos_data);
pCompressor->pos_data = NULL;
}
if (pCompressor->intervals) {
free(pCompressor->intervals);
pCompressor->intervals = NULL;
}
}
/**
* Compress one block of data
*
* @param pCompressor compression context
* @param pInWindow pointer to input data window (previously compressed bytes + bytes to compress)
* @param nPreviousBlockSize number of previously compressed bytes (or 0 for none)
* @param nInDataSize number of input bytes to compress
* @param pOutData pointer to output buffer
* @param nMaxOutDataSize maximum size of output buffer, in bytes
*
* @return size of compressed data in output buffer, or -1 if the data is uncompressible
*/
int lzsa_compressor_shrink_block(lzsa_compressor *pCompressor, unsigned char *pInWindow, const int nPreviousBlockSize, const int nInDataSize, unsigned char *pOutData, const int nMaxOutDataSize) {
int nCompressedSize;
if (pCompressor->flags & LZSA_FLAG_RAW_BACKWARD) {
lzsa_reverse_buffer(pInWindow + nPreviousBlockSize, nInDataSize);
}
if (lzsa_build_suffix_array(pCompressor, pInWindow, nPreviousBlockSize + nInDataSize))
nCompressedSize = -1;
else {
if (nPreviousBlockSize) {
lzsa_skip_matches(pCompressor, 0, nPreviousBlockSize);
}
lzsa_find_all_matches(pCompressor, (pCompressor->format_version == 2) ? NMATCHES_PER_INDEX_V2 : NMATCHES_PER_INDEX_V1, nPreviousBlockSize, nPreviousBlockSize + nInDataSize);
if (pCompressor->format_version == 1) {
nCompressedSize = lzsa_optimize_and_write_block_v1(pCompressor, pInWindow, nPreviousBlockSize, nInDataSize, pOutData, nMaxOutDataSize);
if (nCompressedSize != -1 && (pCompressor->flags & LZSA_FLAG_RAW_BACKWARD)) {
lzsa_reverse_buffer(pOutData, nCompressedSize);
}
}
else if (pCompressor->format_version == 2) {
nCompressedSize = lzsa_optimize_and_write_block_v2(pCompressor, pInWindow, nPreviousBlockSize, nInDataSize, pOutData, nMaxOutDataSize);
if (nCompressedSize != -1 && (pCompressor->flags & LZSA_FLAG_RAW_BACKWARD)) {
lzsa_reverse_buffer(pOutData, nCompressedSize);
}
}
else {
nCompressedSize = -1;
}
}
if (pCompressor->flags & LZSA_FLAG_RAW_BACKWARD) {
lzsa_reverse_buffer(pInWindow + nPreviousBlockSize, nInDataSize);
}
return nCompressedSize;
}
/**
* Get the number of compression commands issued in compressed data blocks
*
* @return number of commands
*/
int lzsa_compressor_get_command_count(lzsa_compressor *pCompressor) {
return pCompressor->num_commands;
}
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