/* * Copyright (c) Meta Platforms, Inc. and affiliates. * 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 "zstd_deps.h" /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */ #include "cpu.h" /* bmi2 */ #include "mem.h" /* low level memory routines */ #define FSE_STATIC_LINKING_ONLY #include "fse.h" #include "huf.h" #include "zstd_decompress_internal.h" #include "zstd_ddict.h" #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) # include "../legacy/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; #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION dctx->dictContentBeginForFuzzing = dctx->prefixStart; dctx->dictContentEndForFuzzing = dctx->previousDstEnd; #endif 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_customMalloc(dictSize, ddict->cMem); ddict->dictBuffer = internalBuffer; ddict->dictContent = internalBuffer; if (!internalBuffer) return ERROR(memory_allocation); ZSTD_memcpy(internalBuffer, dict, dictSize); } ddict->dictSize = dictSize; ddict->entropy.hufTable[0] = (HUF_DTable)((ZSTD_HUFFDTABLE_CAPACITY_LOG)*0x1000001); /* cover both little and big endian */ /* parse dictionary content */ FORWARD_IF_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_customMalloc(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) { ZSTD_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_customFree(ddict->dictBuffer, cMem); ZSTD_customFree(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 ddict->dictID; }