pcompress/bsc/libbsc/lzp/lzp.cpp
Moinak Ghosh fb25e53b4f Add forked and optimized copy of LGPL version of Libbsc.
Strip out Sort Transform from Libbsc copy.
Reduce Libbsc memory use.
Avoid redundant adler32 of data block in Libbsc.
2013-11-30 22:13:33 +05:30

426 lines
15 KiB
C++

/*-----------------------------------------------------------*/
/* Block Sorting, Lossless Data Compression Library. */
/* Lempel Ziv Prediction */
/*-----------------------------------------------------------*/
/*--
This file is a part of bsc and/or libbsc, a program and a library for
lossless, block-sorting data compression.
Copyright (c) 2009-2012 Ilya Grebnov <ilya.grebnov@gmail.com>
See file AUTHORS for a full list of contributors.
The bsc and libbsc is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
The bsc and libbsc is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the bsc and libbsc. If not, see http://www.gnu.org/licenses/.
Please see the files COPYING and COPYING.LIB for full copyright information.
See also the bsc and libbsc web site:
http://libbsc.com/ for more information.
--*/
#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include "lzp.h"
#include "../platform/platform.h"
#include "../libbsc.h"
#define LIBBSC_LZP_MATCH_FLAG 0xf2
static INLINE int bsc_lzp_num_blocks(int n)
{
if (n < 256 * 1024) return 1;
if (n < 4 * 1024 * 1024) return 2;
if (n < 16 * 1024 * 1024) return 4;
return 8;
}
int bsc_lzp_encode_block(const unsigned char * input, const unsigned char * inputEnd, unsigned char * output, unsigned char * outputEnd, int hashSize, int minLen)
{
if (inputEnd - input < 16)
{
return LIBBSC_NOT_COMPRESSIBLE;
}
if (int * lookup = (int *)bsc_zero_malloc((int)(1 << hashSize) * sizeof(int)))
{
unsigned int mask = (int)(1 << hashSize) - 1;
const unsigned char * inputStart = input;
const unsigned char * outputStart = output;
const unsigned char * outputEOB = outputEnd - 4;
unsigned int context = 0;
for (int i = 0; i < 4; ++i)
{
context = (context << 8) | (*output++ = *input++);
}
const unsigned char * heuristic = input;
const unsigned char * inputMinLenEnd = inputEnd - minLen - 8;
while ((input < inputMinLenEnd) && (output < outputEOB))
{
unsigned int index = ((context >> 15) ^ context ^ (context >> 3)) & mask;
int value = lookup[index]; lookup[index] = (int)(input - inputStart);
if (value > 0)
{
const unsigned char * reference = inputStart + value;
if ((*(unsigned int *)(input + minLen - 4) == *(unsigned int *)(reference + minLen - 4)) && (*(unsigned int *)(input) == *(unsigned int *)(reference)))
{
if ((heuristic > input) && (*(unsigned int *)heuristic != *(unsigned int *)(reference + (heuristic - input))))
{
goto LIBBSC_LZP_MATCH_NOT_FOUND;
}
int len = 4;
for (; input + len < inputMinLenEnd; len += 4)
{
if (*(unsigned int *)(input + len) != *(unsigned int *)(reference + len)) break;
}
if (len < minLen)
{
if (heuristic < input + len) heuristic = input + len;
goto LIBBSC_LZP_MATCH_NOT_FOUND;
}
if (input[len] == reference[len]) len++;
if (input[len] == reference[len]) len++;
if (input[len] == reference[len]) len++;
input += len; context = input[-1] | (input[-2] << 8) | (input[-3] << 16) | (input[-4] << 24);
*output++ = LIBBSC_LZP_MATCH_FLAG;
len -= minLen; while (len >= 254) { len -= 254; *output++ = 254; if (output >= outputEOB) break; }
*output++ = (unsigned char)(len);
}
else
{
LIBBSC_LZP_MATCH_NOT_FOUND:
unsigned char next = *output++ = *input++; context = (context << 8) | next;
if (next == LIBBSC_LZP_MATCH_FLAG) *output++ = 255;
}
}
else
{
context = (context << 8) | (*output++ = *input++);
}
}
while ((input < inputEnd) && (output < outputEOB))
{
unsigned int index = ((context >> 15) ^ context ^ (context >> 3)) & mask;
int value = lookup[index]; lookup[index] = (int)(input - inputStart);
if (value > 0)
{
unsigned char next = *output++ = *input++; context = (context << 8) | next;
if (next == LIBBSC_LZP_MATCH_FLAG) *output++ = 255;
}
else
{
context = (context << 8) | (*output++ = *input++);
}
}
bsc_free(lookup);
return (output >= outputEOB) ? LIBBSC_NOT_COMPRESSIBLE : (int)(output - outputStart);
}
return LIBBSC_NOT_ENOUGH_MEMORY;
}
int bsc_lzp_decode_block(const unsigned char * input, const unsigned char * inputEnd, unsigned char * output, int hashSize, int minLen)
{
if (inputEnd - input < 4)
{
return LIBBSC_UNEXPECTED_EOB;
}
if (int * lookup = (int *)bsc_zero_malloc((int)(1 << hashSize) * sizeof(int)))
{
unsigned int mask = (int)(1 << hashSize) - 1;
const unsigned char * outputStart = output;
unsigned int context = 0;
for (int i = 0; i < 4; ++i)
{
context = (context << 8) | (*output++ = *input++);
}
while (input < inputEnd)
{
unsigned int index = ((context >> 15) ^ context ^ (context >> 3)) & mask;
int value = lookup[index]; lookup[index] = (int)(output - outputStart);
if (*input == LIBBSC_LZP_MATCH_FLAG && value > 0)
{
input++;
if (*input != 255)
{
int len = minLen; while (true) { len += *input; if (*input++ != 254) break; }
const unsigned char * reference = outputStart + value;
unsigned char * outputEnd = output + len;
if (output - reference < 4)
{
int offset[4] = {0, 3, 2, 3};
*output++ = *reference++;
*output++ = *reference++;
*output++ = *reference++;
*output++ = *reference++;
reference -= offset[output - reference];
}
while (output < outputEnd) { *(unsigned int *)output = *(unsigned int*)reference; output += 4; reference += 4; }
output = outputEnd; context = output[-1] | (output[-2] << 8) | (output[-3] << 16) | (output[-4] << 24);
}
else
{
input++; context = (context << 8) | (*output++ = LIBBSC_LZP_MATCH_FLAG);
}
}
else
{
context = (context << 8) | (*output++ = *input++);
}
}
bsc_free(lookup);
return (int)(output - outputStart);
}
return LIBBSC_NOT_ENOUGH_MEMORY;
}
int bsc_lzp_compress_serial(const unsigned char * input, unsigned char * output, int n, int hashSize, int minLen)
{
if (bsc_lzp_num_blocks(n) == 1)
{
int result = bsc_lzp_encode_block(input, input + n, output + 1, output + n - 1, hashSize, minLen);
if (result >= LIBBSC_NO_ERROR) result = (output[0] = 1, result + 1);
return result;
}
int nBlocks = bsc_lzp_num_blocks(n);
int chunkSize = n / nBlocks;
int outputPtr = 1 + 8 * nBlocks;
output[0] = nBlocks;
for (int blockId = 0; blockId < nBlocks; ++blockId)
{
int inputStart = blockId * chunkSize;
int inputSize = blockId != nBlocks - 1 ? chunkSize : n - inputStart;
int outputSize = inputSize; if (outputSize > n - outputPtr) outputSize = n - outputPtr;
int result = bsc_lzp_encode_block(input + inputStart, input + inputStart + inputSize, output + outputPtr, output + outputPtr + outputSize, hashSize, minLen);
if (result < LIBBSC_NO_ERROR)
{
if (outputPtr + inputSize >= n) return LIBBSC_NOT_COMPRESSIBLE;
result = inputSize; memcpy(output + outputPtr, input + inputStart, inputSize);
}
*(int *)(output + 1 + 8 * blockId + 0) = inputSize;
*(int *)(output + 1 + 8 * blockId + 4) = result;
outputPtr += result;
}
return outputPtr;
}
#ifdef LIBBSC_OPENMP
int bsc_lzp_compress_parallel(const unsigned char * input, unsigned char * output, int n, int hashSize, int minLen)
{
if (unsigned char * buffer = (unsigned char *)bsc_malloc(n * sizeof(unsigned char)))
{
int compressionResult[ALPHABET_SIZE];
int nBlocks = bsc_lzp_num_blocks(n);
int result = LIBBSC_NO_ERROR;
int chunkSize = n / nBlocks;
int numThreads = omp_get_max_threads();
if (numThreads > nBlocks) numThreads = nBlocks;
output[0] = nBlocks;
#pragma omp parallel num_threads(numThreads) if(numThreads > 1)
{
if (omp_get_num_threads() == 1)
{
result = bsc_lzp_compress_serial(input, output, n, hashSize, minLen);
}
else
{
#pragma omp for schedule(dynamic)
for (int blockId = 0; blockId < nBlocks; ++blockId)
{
int blockStart = blockId * chunkSize;
int blockSize = blockId != nBlocks - 1 ? chunkSize : n - blockStart;
compressionResult[blockId] = bsc_lzp_encode_block(input + blockStart, input + blockStart + blockSize, buffer + blockStart, buffer + blockStart + blockSize, hashSize, minLen);
if (compressionResult[blockId] < LIBBSC_NO_ERROR) compressionResult[blockId] = blockSize;
*(int *)(output + 1 + 8 * blockId + 0) = blockSize;
*(int *)(output + 1 + 8 * blockId + 4) = compressionResult[blockId];
}
#pragma omp single
{
result = 1 + 8 * nBlocks;
for (int blockId = 0; blockId < nBlocks; ++blockId)
{
result += compressionResult[blockId];
}
if (result >= n) result = LIBBSC_NOT_COMPRESSIBLE;
}
if (result >= LIBBSC_NO_ERROR)
{
#pragma omp for schedule(dynamic)
for (int blockId = 0; blockId < nBlocks; ++blockId)
{
int blockStart = blockId * chunkSize;
int blockSize = blockId != nBlocks - 1 ? chunkSize : n - blockStart;
int outputPtr = 1 + 8 * nBlocks;
for (int p = 0; p < blockId; ++p) outputPtr += compressionResult[p];
if (compressionResult[blockId] != blockSize)
{
memcpy(output + outputPtr, buffer + blockStart, compressionResult[blockId]);
}
else
{
memcpy(output + outputPtr, input + blockStart, compressionResult[blockId]);
}
}
}
}
}
bsc_free(buffer);
return result;
}
return LIBBSC_NOT_ENOUGH_MEMORY;
}
#endif
int bsc_lzp_compress(const unsigned char * input, unsigned char * output, int n, int hashSize, int minLen, int features)
{
#ifdef LIBBSC_OPENMP
if ((bsc_lzp_num_blocks(n) != 1) && (features & LIBBSC_FEATURE_MULTITHREADING))
{
return bsc_lzp_compress_parallel(input, output, n, hashSize, minLen);
}
#endif
return bsc_lzp_compress_serial(input, output, n, hashSize, minLen);
}
int bsc_lzp_decompress(const unsigned char * input, unsigned char * output, int n, int hashSize, int minLen, int features)
{
int nBlocks = input[0];
if (nBlocks == 1)
{
return bsc_lzp_decode_block(input + 1, input + n, output, hashSize, minLen);
}
int decompressionResult[ALPHABET_SIZE];
#ifdef LIBBSC_OPENMP
if (features & LIBBSC_FEATURE_MULTITHREADING)
{
#pragma omp parallel for schedule(dynamic)
for (int blockId = 0; blockId < nBlocks; ++blockId)
{
int inputPtr = 0; for (int p = 0; p < blockId; ++p) inputPtr += *(int *)(input + 1 + 8 * p + 4);
int outputPtr = 0; for (int p = 0; p < blockId; ++p) outputPtr += *(int *)(input + 1 + 8 * p + 0);
inputPtr += 1 + 8 * nBlocks;
int inputSize = *(int *)(input + 1 + 8 * blockId + 4);
int outputSize = *(int *)(input + 1 + 8 * blockId + 0);
if (inputSize != outputSize)
{
decompressionResult[blockId] = bsc_lzp_decode_block(input + inputPtr, input + inputPtr + inputSize, output + outputPtr, hashSize, minLen);
}
else
{
decompressionResult[blockId] = inputSize; memcpy(output + outputPtr, input + inputPtr, inputSize);
}
}
}
else
#endif
{
for (int blockId = 0; blockId < nBlocks; ++blockId)
{
int inputPtr = 0; for (int p = 0; p < blockId; ++p) inputPtr += *(int *)(input + 1 + 8 * p + 4);
int outputPtr = 0; for (int p = 0; p < blockId; ++p) outputPtr += *(int *)(input + 1 + 8 * p + 0);
inputPtr += 1 + 8 * nBlocks;
int inputSize = *(int *)(input + 1 + 8 * blockId + 4);
int outputSize = *(int *)(input + 1 + 8 * blockId + 0);
if (inputSize != outputSize)
{
decompressionResult[blockId] = bsc_lzp_decode_block(input + inputPtr, input + inputPtr + inputSize, output + outputPtr, hashSize, minLen);
}
else
{
decompressionResult[blockId] = inputSize; memcpy(output + outputPtr, input + inputPtr, inputSize);
}
}
}
int dataSize = 0, result = LIBBSC_NO_ERROR;
for (int blockId = 0; blockId < nBlocks; ++blockId)
{
if (decompressionResult[blockId] < LIBBSC_NO_ERROR) result = decompressionResult[blockId];
dataSize += decompressionResult[blockId];
}
return (result == LIBBSC_NO_ERROR) ? dataSize : result;
}
/*-----------------------------------------------------------*/
/* End lzp.cpp */
/*-----------------------------------------------------------*/