lzsa/src/dictionary.c

104 lines
3.5 KiB
C

/*
* dictionary.c - dictionary 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/
*
*/
#define _POSIX_C_SOURCE 200808
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include "format.h"
#include "lib.h"
/**
* Load dictionary contents
*
* @param pszDictionaryFilename name of dictionary file, or NULL for none
* @param ppDictionaryData pointer to returned dictionary contents, or NULL for none
* @param pDictionaryDataSize pointer to returned size of dictionary contents, or 0
*
* @return LZSA_OK for success, or an error value from lzsa_status_t
*/
int lzsa_dictionary_load(const char *pszDictionaryFilename, void **ppDictionaryData, int *pDictionaryDataSize) {
unsigned char *pDictionaryData = NULL;
int nDictionaryDataSize = 0;
if (pszDictionaryFilename) {
pDictionaryData = (unsigned char *)malloc(BLOCK_SIZE);
if (!pDictionaryData) {
return LZSA_ERROR_MEMORY;
}
FILE *pDictionaryFile = fopen(pszDictionaryFilename, "rb");
if (!pDictionaryFile) {
free(pDictionaryData);
pDictionaryData = NULL;
return LZSA_ERROR_DICTIONARY;
}
fseek(pDictionaryFile, 0, SEEK_END);
#ifdef _WIN32
__int64 nDictionaryFileSize = _ftelli64(pDictionaryFile);
#else
off_t nDictionaryFileSize = ftello(pDictionaryFile);
#endif
if (nDictionaryFileSize > BLOCK_SIZE) {
/* Use the last BLOCK_SIZE bytes of the dictionary */
fseek(pDictionaryFile, -BLOCK_SIZE, SEEK_END);
}
else {
fseek(pDictionaryFile, 0, SEEK_SET);
}
nDictionaryDataSize = (int)fread(pDictionaryData, 1, BLOCK_SIZE, pDictionaryFile);
if (nDictionaryDataSize < 0)
nDictionaryDataSize = 0;
fclose(pDictionaryFile);
pDictionaryFile = NULL;
}
*ppDictionaryData = pDictionaryData;
*pDictionaryDataSize = nDictionaryDataSize;
return LZSA_OK;
}
/**
* Free dictionary contents
*
* @param ppDictionaryData pointer to pointer to dictionary contents
*/
void lzsa_dictionary_free(void **ppDictionaryData) {
if (*ppDictionaryData) {
free(*ppDictionaryData);
*ppDictionaryData = NULL;
}
}