pcompress/lzp/lzp.c

468 lines
16 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>
Copyright (c) 2012 Moinak Ghosh <moinakg@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.
--*/
/*
* TODO: Port the parallel implementation.
*/
#undef LZP_OPENMP
#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include <allocator.h>
#include <sys/types.h>
#include "lzp.h"
#define LZP_MATCH_FLAG 0xf2
static
inline int bsc_lzp_num_blocks(int64_t n)
{
int nb;
if (n < 256 * 1024) return 1;
if (n < 4 * 1024 * 1024) return 2;
if (n < 16 * 1024 * 1024) return 4;
if (n < LZP_MAX_BLOCK) return 8;
nb = n / LZP_MAX_BLOCK;
if (n % LZP_MAX_BLOCK) nb++;
return (nb);
}
static
int bsc_lzp_encode_block(const unsigned char * input, const unsigned char * inputEnd, unsigned char * output, unsigned char * outputEnd, int hashSize, int minLen)
{
int *lookup, i;
if (inputEnd - input < 16)
{
return LZP_NOT_COMPRESSIBLE;
}
if (lookup = (int *)slab_calloc(NULL, (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 (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 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 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++ = LZP_MATCH_FLAG;
len -= minLen; while (len >= 254) { len -= 254; *output++ = 254; if (output >= outputEOB) break; }
*output++ = (unsigned char)(len);
}
else
{
unsigned char next;
LZP_MATCH_NOT_FOUND:
next = *output++ = *input++; context = (context << 8) | next;
if (next == 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 == LZP_MATCH_FLAG) *output++ = 255;
}
else
{
context = (context << 8) | (*output++ = *input++);
}
}
slab_free(NULL, lookup);
return (output >= outputEOB) ? LZP_NOT_COMPRESSIBLE : (int)(output - outputStart);
}
return LZP_NOT_ENOUGH_MEMORY;
}
static
int bsc_lzp_decode_block(const unsigned char * input, const unsigned char * inputEnd, unsigned char * output, int hashSize, int minLen)
{
int *lookup, i;
if (inputEnd - input < 4)
{
return LZP_UNEXPECTED_EOB;
}
if (lookup = (int *)slab_calloc(NULL, (int)(1 << hashSize), sizeof(int)))
{
unsigned int mask = (int)(1 << hashSize) - 1;
const unsigned char * outputStart = output;
unsigned int context = 0;
for (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 == LZP_MATCH_FLAG && value > 0)
{
input++;
if (*input != 255)
{
int len = minLen; while (1) { 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++ = LZP_MATCH_FLAG);
}
}
else
{
context = (context << 8) | (*output++ = *input++);
}
}
slab_free(NULL, lookup);
return (int)(output - outputStart);
}
return LZP_NOT_ENOUGH_MEMORY;
}
static
int64_t bsc_lzp_compress_serial(const unsigned char * input, unsigned char * output, int64_t 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 >= LZP_NO_ERROR) result = (output[0] = 1, result + 1);
return result;
}
int nBlocks = bsc_lzp_num_blocks(n);
int chunkSize;
int blockId;
int64_t outputPtr = 1 + 8 * nBlocks;
if (n > LZP_MAX_BLOCK)
chunkSize = LZP_MAX_BLOCK;
else
chunkSize = n / nBlocks;
output[0] = nBlocks;
for (blockId = 0; blockId < nBlocks; ++blockId)
{
int64_t 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 < LZP_NO_ERROR)
{
if (outputPtr + inputSize >= n) return LZP_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 LZP_OPENMP
static
int bsc_lzp_compress_parallel(const unsigned char * input, unsigned char * output, int64_t 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 = LZP_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] < LZP_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 = LZP_NOT_COMPRESSIBLE;
}
if (result >= LZP_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 LZP_NOT_ENOUGH_MEMORY;
}
#endif
int64_t lzp_compress(const unsigned char * input, unsigned char * output, int64_t n, int hashSize, int minLen, int features)
{
#ifdef LZP_OPENMP
if ((bsc_lzp_num_blocks(n) != 1) && (features & LZP_FEATURE_MULTITHREADING))
{
return bsc_lzp_compress_parallel(input, output, n, hashSize, minLen);
}
#endif
return bsc_lzp_compress_serial(input, output, n, hashSize, minLen);
}
int64_t lzp_decompress(const unsigned char * input, unsigned char * output, int64_t 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 LZP_OPENMP
if (features & LZP_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
{
int blockId, p;
for (blockId = 0; blockId < nBlocks; ++blockId)
{
int64_t inputPtr = 0; for (p = 0; p < blockId; ++p) inputPtr += *(int *)(input + 1 + 8 * p + 4);
int64_t outputPtr = 0; for (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);
}
}
}
int64_t dataSize = 0;
int result = LZP_NO_ERROR;
int blockId;
for (blockId = 0; blockId < nBlocks; ++blockId)
{
if (decompressionResult[blockId] < LZP_NO_ERROR) result = decompressionResult[blockId];
dataSize += decompressionResult[blockId];
}
return (result == LZP_NO_ERROR) ? dataSize : result;
}
/*
* Counter-intuitively we use a larger hash (with better LZP compression) for lower global
* compression levels. So that LZP preprocessing plays along nicely with the primary
* compression algorithm being used and actually provides a benefit.
*/
int lzp_hash_size(int level) {
if (level > 7) {
return (LZP_DEFAULT_LZPHASHSIZE + 2);
} else if (level > 5) {
return (LZP_DEFAULT_LZPHASHSIZE + 3);
} else if (level > 3) {
return (LZP_DEFAULT_LZPHASHSIZE + 4);
} else {
return (LZP_DEFAULT_LZPHASHSIZE + 5);
}
}
/*-----------------------------------------------------------*/
/* End lzp.cpp */
/*-----------------------------------------------------------*/