lib/zstd/decompress/zstd_ddict.c

   1 /*
   2  * Copyright (c) Yann Collet, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under both the BSD-style license (found in the
   6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
   7  * in the COPYING file in the root directory of this source tree).
   8  * You may select, at your option, one of the above-listed licenses.
   9  */
  10
  11 /* zstd_ddict.c :
  12  * concentrates all logic that needs to know the internals of ZSTD_DDict object */
  13
  14 /*-*******************************************************
  15 *  Dependencies
  16 *********************************************************/
  17 #include "../common/zstd_deps.h"   /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */
  18 #include "../common/cpu.h"         /* bmi2 */
  19 #include "../common/mem.h"         /* low level memory routines */
  20 #define FSE_STATIC_LINKING_ONLY
  21 #include "../common/fse.h"
  22 #define HUF_STATIC_LINKING_ONLY
  23 #include "../common/huf.h"
  24 #include "zstd_decompress_internal.h"
  25 #include "zstd_ddict.h"
  26
  27
  28
  29
  30 /*-*******************************************************
  31 *  Types
  32 *********************************************************/
  33 struct ZSTD_DDict_s {
  34     void* dictBuffer;
  35     const void* dictContent;
  36     size_t dictSize;
  37     ZSTD_entropyDTables_t entropy;
  38     U32 dictID;
  39     U32 entropyPresent;
  40     ZSTD_customMem cMem;
  41 };  /* typedef'd to ZSTD_DDict within "zstd.h" */
  42
  43 const void* ZSTD_DDict_dictContent(const ZSTD_DDict* ddict)
  44 {
  45     assert(ddict != NULL);
  46     return ddict->dictContent;
  47 }
  48
  49 size_t ZSTD_DDict_dictSize(const ZSTD_DDict* ddict)
  50 {
  51     assert(ddict != NULL);
  52     return ddict->dictSize;
  53 }
  54
  55 void ZSTD_copyDDictParameters(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
  56 {
  57     DEBUGLOG(4, "ZSTD_copyDDictParameters");
  58     assert(dctx != NULL);
  59     assert(ddict != NULL);
  60     dctx->dictID = ddict->dictID;
  61     dctx->prefixStart = ddict->dictContent;
  62     dctx->virtualStart = ddict->dictContent;
  63     dctx->dictEnd = (const BYTE*)ddict->dictContent + ddict->dictSize;
  64     dctx->previousDstEnd = dctx->dictEnd;
  65 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
  66     dctx->dictContentBeginForFuzzing = dctx->prefixStart;
  67     dctx->dictContentEndForFuzzing = dctx->previousDstEnd;
  68 #endif
  69     if (ddict->entropyPresent) {
  70         dctx->litEntropy = 1;
  71         dctx->fseEntropy = 1;
  72         dctx->LLTptr = ddict->entropy.LLTable;
  73         dctx->MLTptr = ddict->entropy.MLTable;
  74         dctx->OFTptr = ddict->entropy.OFTable;
  75         dctx->HUFptr = ddict->entropy.hufTable;
  76         dctx->entropy.rep[0] = ddict->entropy.rep[0];
  77         dctx->entropy.rep[1] = ddict->entropy.rep[1];
  78         dctx->entropy.rep[2] = ddict->entropy.rep[2];
  79     } else {
  80         dctx->litEntropy = 0;
  81         dctx->fseEntropy = 0;
  82     }
  83 }
  84
  85
  86 static size_t
  87 ZSTD_loadEntropy_intoDDict(ZSTD_DDict* ddict,
  88                            ZSTD_dictContentType_e dictContentType)
  89 {
  90     ddict->dictID = 0;
  91     ddict->entropyPresent = 0;
  92     if (dictContentType == ZSTD_dct_rawContent) return 0;
  93
  94     if (ddict->dictSize < 8) {
  95         if (dictContentType == ZSTD_dct_fullDict)
  96             return ERROR(dictionary_corrupted);   /* only accept specified dictionaries */
  97         return 0;   /* pure content mode */
  98     }
  99     {   U32 const magic = MEM_readLE32(ddict->dictContent);
 100         if (magic != ZSTD_MAGIC_DICTIONARY) {
 101             if (dictContentType == ZSTD_dct_fullDict)
 102                 return ERROR(dictionary_corrupted);   /* only accept specified dictionaries */
 103             return 0;   /* pure content mode */
 104         }
 105     }
 106     ddict->dictID = MEM_readLE32((const char*)ddict->dictContent + ZSTD_FRAMEIDSIZE);
 107
 108     /* load entropy tables */
 109     RETURN_ERROR_IF(ZSTD_isError(ZSTD_loadDEntropy(
 110             &ddict->entropy, ddict->dictContent, ddict->dictSize)),
 111         dictionary_corrupted, "");
 112     ddict->entropyPresent = 1;
 113     return 0;
 114 }
 115
 116
 117 static size_t ZSTD_initDDict_internal(ZSTD_DDict* ddict,
 118                                       const void* dict, size_t dictSize,
 119                                       ZSTD_dictLoadMethod_e dictLoadMethod,
 120                                       ZSTD_dictContentType_e dictContentType)
 121 {
 122     if ((dictLoadMethod == ZSTD_dlm_byRef) || (!dict) || (!dictSize)) {
 123         ddict->dictBuffer = NULL;
 124         ddict->dictContent = dict;
 125         if (!dict) dictSize = 0;
 126     } else {
 127         void* const internalBuffer = ZSTD_customMalloc(dictSize, ddict->cMem);
 128         ddict->dictBuffer = internalBuffer;
 129         ddict->dictContent = internalBuffer;
 130         if (!internalBuffer) return ERROR(memory_allocation);
 131         ZSTD_memcpy(internalBuffer, dict, dictSize);
 132     }
 133     ddict->dictSize = dictSize;
 134     ddict->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001);  /* cover both little and big endian */
 135
 136     /* parse dictionary content */
 137     FORWARD_IF_ERROR( ZSTD_loadEntropy_intoDDict(ddict, dictContentType) , "");
 138
 139     return 0;
 140 }
 141
 142 ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
 143                                       ZSTD_dictLoadMethod_e dictLoadMethod,
 144                                       ZSTD_dictContentType_e dictContentType,
 145                                       ZSTD_customMem customMem)
 146 {
 147     if ((!customMem.customAlloc) ^ (!customMem.customFree)) return NULL;
 148
 149     {   ZSTD_DDict* const ddict = (ZSTD_DDict*) ZSTD_customMalloc(sizeof(ZSTD_DDict), customMem);
 150         if (ddict == NULL) return NULL;
 151         ddict->cMem = customMem;
 152         {   size_t const initResult = ZSTD_initDDict_internal(ddict,
 153                                             dict, dictSize,
 154                                             dictLoadMethod, dictContentType);
 155             if (ZSTD_isError(initResult)) {
 156                 ZSTD_freeDDict(ddict);
 157                 return NULL;
 158         }   }
 159         return ddict;
 160     }
 161 }
 162
 163 /*! ZSTD_createDDict() :
 164 *   Create a digested dictionary, to start decompression without startup delay.
 165 *   `dict` content is copied inside DDict.
 166 *   Consequently, `dict` can be released after `ZSTD_DDict` creation */
 167 ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize)
 168 {
 169     ZSTD_customMem const allocator = { NULL, NULL, NULL };
 170     return ZSTD_createDDict_advanced(dict, dictSize, ZSTD_dlm_byCopy, ZSTD_dct_auto, allocator);
 171 }
 172
 173 /*! ZSTD_createDDict_byReference() :
 174  *  Create a digested dictionary, to start decompression without startup delay.
 175  *  Dictionary content is simply referenced, it will be accessed during decompression.
 176  *  Warning : dictBuffer must outlive DDict (DDict must be freed before dictBuffer) */
 177 ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize)
 178 {
 179     ZSTD_customMem const allocator = { NULL, NULL, NULL };
 180     return ZSTD_createDDict_advanced(dictBuffer, dictSize, ZSTD_dlm_byRef, ZSTD_dct_auto, allocator);
 181 }
 182
 183
 184 const ZSTD_DDict* ZSTD_initStaticDDict(
 185                                 void* sBuffer, size_t sBufferSize,
 186                                 const void* dict, size_t dictSize,
 187                                 ZSTD_dictLoadMethod_e dictLoadMethod,
 188                                 ZSTD_dictContentType_e dictContentType)
 189 {
 190     size_t const neededSpace = sizeof(ZSTD_DDict)
 191                              + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
 192     ZSTD_DDict* const ddict = (ZSTD_DDict*)sBuffer;
 193     assert(sBuffer != NULL);
 194     assert(dict != NULL);
 195     if ((size_t)sBuffer & 7) return NULL;   /* 8-aligned */
 196     if (sBufferSize < neededSpace) return NULL;
 197     if (dictLoadMethod == ZSTD_dlm_byCopy) {
 198         ZSTD_memcpy(ddict+1, dict, dictSize);  /* local copy */
 199         dict = ddict+1;
 200     }
 201     if (ZSTD_isError( ZSTD_initDDict_internal(ddict,
 202                                               dict, dictSize,
 203                                               ZSTD_dlm_byRef, dictContentType) ))
 204         return NULL;
 205     return ddict;
 206 }
 207
 208
 209 size_t ZSTD_freeDDict(ZSTD_DDict* ddict)
 210 {
 211     if (ddict==NULL) return 0;   /* support free on NULL */
 212     {   ZSTD_customMem const cMem = ddict->cMem;
 213         ZSTD_customFree(ddict->dictBuffer, cMem);
 214         ZSTD_customFree(ddict, cMem);
 215         return 0;
 216     }
 217 }
 218
 219 /*! ZSTD_estimateDDictSize() :
 220  *  Estimate amount of memory that will be needed to create a dictionary for decompression.
 221  *  Note : dictionary created by reference using ZSTD_dlm_byRef are smaller */
 222 size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod)
 223 {
 224     return sizeof(ZSTD_DDict) + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
 225 }
 226
 227 size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict)
 228 {
 229     if (ddict==NULL) return 0;   /* support sizeof on NULL */
 230     return sizeof(*ddict) + (ddict->dictBuffer ? ddict->dictSize : 0) ;
 231 }
 232
 233 /*! ZSTD_getDictID_fromDDict() :
 234  *  Provides the dictID of the dictionary loaded into `ddict`.
 235  *  If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
 236  *  Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
 237 unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict)
 238 {
 239     if (ddict==NULL) return 0;
 240     return ZSTD_getDictID_fromDict(ddict->dictContent, ddict->dictSize);
 241 }