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zstd/lib/decompress/zstd_ddict.c

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/*
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/
/* zstd_ddict.c :
* concentrates all logic that needs to know the internals of ZSTD_DDict object */
/*-*******************************************************
* Dependencies
*********************************************************/
#include <string.h> /* memcpy, memmove, memset */
#include "cpu.h" /* bmi2 */
#include "mem.h" /* low level memory routines */
#define FSE_STATIC_LINKING_ONLY
#include "fse.h"
#define HUF_STATIC_LINKING_ONLY
#include "huf.h"
#include "zstd_decompress_internal.h"
#include "zstd_ddict.h"
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
# include "zstd_legacy.h"
#endif
/*-*******************************************************
* Types
*********************************************************/
struct ZSTD_DDict_s {
void* dictBuffer;
const void* dictContent;
size_t dictSize;
ZSTD_entropyDTables_t entropy;
U32 dictID;
U32 entropyPresent;
ZSTD_customMem cMem;
}; /* typedef'd to ZSTD_DDict within "zstd.h" */
const void* ZSTD_DDict_dictContent(const ZSTD_DDict* ddict)
{
assert(ddict != NULL);
return ddict->dictContent;
}
size_t ZSTD_DDict_dictSize(const ZSTD_DDict* ddict)
{
assert(ddict != NULL);
return ddict->dictSize;
}
void ZSTD_copyDDictParameters(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
{
DEBUGLOG(4, "ZSTD_copyDDictParameters");
assert(dctx != NULL);
assert(ddict != NULL);
dctx->dictID = ddict->dictID;
dctx->prefixStart = ddict->dictContent;
dctx->virtualStart = ddict->dictContent;
dctx->dictEnd = (const BYTE*)ddict->dictContent + ddict->dictSize;
dctx->previousDstEnd = dctx->dictEnd;
if (ddict->entropyPresent) {
dctx->litEntropy = 1;
dctx->fseEntropy = 1;
dctx->LLTptr = ddict->entropy.LLTable;
dctx->MLTptr = ddict->entropy.MLTable;
dctx->OFTptr = ddict->entropy.OFTable;
dctx->HUFptr = ddict->entropy.hufTable;
dctx->entropy.rep[0] = ddict->entropy.rep[0];
dctx->entropy.rep[1] = ddict->entropy.rep[1];
dctx->entropy.rep[2] = ddict->entropy.rep[2];
} else {
dctx->litEntropy = 0;
dctx->fseEntropy = 0;
}
}
static size_t
ZSTD_loadEntropy_intoDDict(ZSTD_DDict* ddict,
ZSTD_dictContentType_e dictContentType)
{
ddict->dictID = 0;
ddict->entropyPresent = 0;
if (dictContentType == ZSTD_dct_rawContent) return 0;
if (ddict->dictSize < 8) {
if (dictContentType == ZSTD_dct_fullDict)
return ERROR(dictionary_corrupted); /* only accept specified dictionaries */
return 0; /* pure content mode */
}
{ U32 const magic = MEM_readLE32(ddict->dictContent);
if (magic != ZSTD_MAGIC_DICTIONARY) {
if (dictContentType == ZSTD_dct_fullDict)
return ERROR(dictionary_corrupted); /* only accept specified dictionaries */
return 0; /* pure content mode */
}
}
ddict->dictID = MEM_readLE32((const char*)ddict->dictContent + ZSTD_FRAMEIDSIZE);
/* load entropy tables */
RETURN_ERROR_IF(ZSTD_isError(ZSTD_loadDEntropy(
&ddict->entropy, ddict->dictContent, ddict->dictSize)),
dictionary_corrupted);
ddict->entropyPresent = 1;
return 0;
}
static size_t ZSTD_initDDict_internal(ZSTD_DDict* ddict,
const void* dict, size_t dictSize,
ZSTD_dictLoadMethod_e dictLoadMethod,
ZSTD_dictContentType_e dictContentType)
{
if ((dictLoadMethod == ZSTD_dlm_byRef) || (!dict) || (!dictSize)) {
ddict->dictBuffer = NULL;
ddict->dictContent = dict;
if (!dict) dictSize = 0;
} else {
void* const internalBuffer = ZSTD_malloc(dictSize, ddict->cMem);
ddict->dictBuffer = internalBuffer;
ddict->dictContent = internalBuffer;
if (!internalBuffer) return ERROR(memory_allocation);
memcpy(internalBuffer, dict, dictSize);
}
ddict->dictSize = dictSize;
ddict->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); /* cover both little and big endian */
/* parse dictionary content */
FORWARD_ERROR( ZSTD_loadEntropy_intoDDict(ddict, dictContentType) );
return 0;
}
ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
ZSTD_dictLoadMethod_e dictLoadMethod,
ZSTD_dictContentType_e dictContentType,
ZSTD_customMem customMem)
{
if (!customMem.customAlloc ^ !customMem.customFree) return NULL;
{ ZSTD_DDict* const ddict = (ZSTD_DDict*) ZSTD_malloc(sizeof(ZSTD_DDict), customMem);
if (ddict == NULL) return NULL;
ddict->cMem = customMem;
{ size_t const initResult = ZSTD_initDDict_internal(ddict,
dict, dictSize,
dictLoadMethod, dictContentType);
if (ZSTD_isError(initResult)) {
ZSTD_freeDDict(ddict);
return NULL;
} }
return ddict;
}
}
/*! ZSTD_createDDict() :
* Create a digested dictionary, to start decompression without startup delay.
* `dict` content is copied inside DDict.
* Consequently, `dict` can be released after `ZSTD_DDict` creation */
ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize)
{
ZSTD_customMem const allocator = { NULL, NULL, NULL };
return ZSTD_createDDict_advanced(dict, dictSize, ZSTD_dlm_byCopy, ZSTD_dct_auto, allocator);
}
/*! ZSTD_createDDict_byReference() :
* Create a digested dictionary, to start decompression without startup delay.
* Dictionary content is simply referenced, it will be accessed during decompression.
* Warning : dictBuffer must outlive DDict (DDict must be freed before dictBuffer) */
ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize)
{
ZSTD_customMem const allocator = { NULL, NULL, NULL };
return ZSTD_createDDict_advanced(dictBuffer, dictSize, ZSTD_dlm_byRef, ZSTD_dct_auto, allocator);
}
const ZSTD_DDict* ZSTD_initStaticDDict(
void* sBuffer, size_t sBufferSize,
const void* dict, size_t dictSize,
ZSTD_dictLoadMethod_e dictLoadMethod,
ZSTD_dictContentType_e dictContentType)
{
size_t const neededSpace = sizeof(ZSTD_DDict)
+ (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
ZSTD_DDict* const ddict = (ZSTD_DDict*)sBuffer;
assert(sBuffer != NULL);
assert(dict != NULL);
if ((size_t)sBuffer & 7) return NULL; /* 8-aligned */
if (sBufferSize < neededSpace) return NULL;
if (dictLoadMethod == ZSTD_dlm_byCopy) {
memcpy(ddict+1, dict, dictSize); /* local copy */
dict = ddict+1;
}
if (ZSTD_isError( ZSTD_initDDict_internal(ddict,
dict, dictSize,
ZSTD_dlm_byRef, dictContentType) ))
return NULL;
return ddict;
}
size_t ZSTD_freeDDict(ZSTD_DDict* ddict)
{
if (ddict==NULL) return 0; /* support free on NULL */
{ ZSTD_customMem const cMem = ddict->cMem;
ZSTD_free(ddict->dictBuffer, cMem);
ZSTD_free(ddict, cMem);
return 0;
}
}
/*! ZSTD_estimateDDictSize() :
* Estimate amount of memory that will be needed to create a dictionary for decompression.
* Note : dictionary created by reference using ZSTD_dlm_byRef are smaller */
size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod)
{
return sizeof(ZSTD_DDict) + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
}
size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict)
{
if (ddict==NULL) return 0; /* support sizeof on NULL */
return sizeof(*ddict) + (ddict->dictBuffer ? ddict->dictSize : 0) ;
}
/*! ZSTD_getDictID_fromDDict() :
* Provides the dictID of the dictionary loaded into `ddict`.
* If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
* Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict)
{
if (ddict==NULL) return 0;
return ZSTD_getDictID_fromDict(ddict->dictContent, ddict->dictSize);
}
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