1/*
2 * Copyright (c) Meta Platforms, Inc. and affiliates.
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/allocations.h" /* ZSTD_customMalloc, ZSTD_customFree */
18#include "../common/zstd_deps.h" /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */
19#include "../common/cpu.h" /* bmi2 */
20#include "../common/mem.h" /* low level memory routines */
21#define FSE_STATIC_LINKING_ONLY
22#include "../common/fse.h"
23#include "../common/huf.h"
24#include "zstd_decompress_internal.h"
25#include "zstd_ddict.h"
26
27#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
28# include "../legacy/zstd_legacy.h"
29#endif
30
31
32
33/*-*******************************************************
34* Types
35*********************************************************/
36struct ZSTD_DDict_s {
37 void* dictBuffer;
38 const void* dictContent;
39 size_t dictSize;
40 ZSTD_entropyDTables_t entropy;
41 U32 dictID;
42 U32 entropyPresent;
43 ZSTD_customMem cMem;
44}; /* typedef'd to ZSTD_DDict within "zstd.h" */
45
46const void* ZSTD_DDict_dictContent(const ZSTD_DDict* ddict)
47{
48 assert(ddict != NULL);
49 return ddict->dictContent;
50}
51
52size_t ZSTD_DDict_dictSize(const ZSTD_DDict* ddict)
53{
54 assert(ddict != NULL);
55 return ddict->dictSize;
56}
57
58void ZSTD_copyDDictParameters(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
59{
60 DEBUGLOG(4, "ZSTD_copyDDictParameters");
61 assert(dctx != NULL);
62 assert(ddict != NULL);
63 dctx->dictID = ddict->dictID;
64 dctx->prefixStart = ddict->dictContent;
65 dctx->virtualStart = ddict->dictContent;
66 dctx->dictEnd = (const BYTE*)ddict->dictContent + ddict->dictSize;
67 dctx->previousDstEnd = dctx->dictEnd;
68#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
69 dctx->dictContentBeginForFuzzing = dctx->prefixStart;
70 dctx->dictContentEndForFuzzing = dctx->previousDstEnd;
71#endif
72 if (ddict->entropyPresent) {
73 dctx->litEntropy = 1;
74 dctx->fseEntropy = 1;
75 dctx->LLTptr = ddict->entropy.LLTable;
76 dctx->MLTptr = ddict->entropy.MLTable;
77 dctx->OFTptr = ddict->entropy.OFTable;
78 dctx->HUFptr = ddict->entropy.hufTable;
79 dctx->entropy.rep[0] = ddict->entropy.rep[0];
80 dctx->entropy.rep[1] = ddict->entropy.rep[1];
81 dctx->entropy.rep[2] = ddict->entropy.rep[2];
82 } else {
83 dctx->litEntropy = 0;
84 dctx->fseEntropy = 0;
85 }
86}
87
88
89static size_t
90ZSTD_loadEntropy_intoDDict(ZSTD_DDict* ddict,
91 ZSTD_dictContentType_e dictContentType)
92{
93 ddict->dictID = 0;
94 ddict->entropyPresent = 0;
95 if (dictContentType == ZSTD_dct_rawContent) return 0;
96
97 if (ddict->dictSize < 8) {
98 if (dictContentType == ZSTD_dct_fullDict)
99 return ERROR(dictionary_corrupted); /* only accept specified dictionaries */
100 return 0; /* pure content mode */
101 }
102 { U32 const magic = MEM_readLE32(ddict->dictContent);
103 if (magic != ZSTD_MAGIC_DICTIONARY) {
104 if (dictContentType == ZSTD_dct_fullDict)
105 return ERROR(dictionary_corrupted); /* only accept specified dictionaries */
106 return 0; /* pure content mode */
107 }
108 }
109 ddict->dictID = MEM_readLE32((const char*)ddict->dictContent + ZSTD_FRAMEIDSIZE);
110
111 /* load entropy tables */
112 RETURN_ERROR_IF(ZSTD_isError(ZSTD_loadDEntropy(
113 &ddict->entropy, ddict->dictContent, ddict->dictSize)),
114 dictionary_corrupted, "");
115 ddict->entropyPresent = 1;
116 return 0;
117}
118
119
120static size_t ZSTD_initDDict_internal(ZSTD_DDict* ddict,
121 const void* dict, size_t dictSize,
122 ZSTD_dictLoadMethod_e dictLoadMethod,
123 ZSTD_dictContentType_e dictContentType)
124{
125 if ((dictLoadMethod == ZSTD_dlm_byRef) || (!dict) || (!dictSize)) {
126 ddict->dictBuffer = NULL;
127 ddict->dictContent = dict;
128 if (!dict) dictSize = 0;
129 } else {
130 void* const internalBuffer = ZSTD_customMalloc(dictSize, ddict->cMem);
131 ddict->dictBuffer = internalBuffer;
132 ddict->dictContent = internalBuffer;
133 if (!internalBuffer) return ERROR(memory_allocation);
134 ZSTD_memcpy(internalBuffer, dict, dictSize);
135 }
136 ddict->dictSize = dictSize;
137 ddict->entropy.hufTable[0] = (HUF_DTable)((ZSTD_HUFFDTABLE_CAPACITY_LOG)*0x1000001); /* cover both little and big endian */
138
139 /* parse dictionary content */
140 FORWARD_IF_ERROR( ZSTD_loadEntropy_intoDDict(ddict, dictContentType) , "");
141
142 return 0;
143}
144
145ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
146 ZSTD_dictLoadMethod_e dictLoadMethod,
147 ZSTD_dictContentType_e dictContentType,
148 ZSTD_customMem customMem)
149{
150 if ((!customMem.customAlloc) ^ (!customMem.customFree)) return NULL;
151
152 { ZSTD_DDict* const ddict = (ZSTD_DDict*) ZSTD_customMalloc(sizeof(ZSTD_DDict), customMem);
153 if (ddict == NULL) return NULL;
154 ddict->cMem = customMem;
155 { size_t const initResult = ZSTD_initDDict_internal(ddict,
156 dict, dictSize,
157 dictLoadMethod, dictContentType);
158 if (ZSTD_isError(initResult)) {
159 ZSTD_freeDDict(ddict);
160 return NULL;
161 } }
162 return ddict;
163 }
164}
165
166/*! ZSTD_createDDict() :
167* Create a digested dictionary, to start decompression without startup delay.
168* `dict` content is copied inside DDict.
169* Consequently, `dict` can be released after `ZSTD_DDict` creation */
170ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize)
171{
172 ZSTD_customMem const allocator = { NULL, NULL, NULL };
173 return ZSTD_createDDict_advanced(dict, dictSize, ZSTD_dlm_byCopy, ZSTD_dct_auto, allocator);
174}
175
176/*! ZSTD_createDDict_byReference() :
177 * Create a digested dictionary, to start decompression without startup delay.
178 * Dictionary content is simply referenced, it will be accessed during decompression.
179 * Warning : dictBuffer must outlive DDict (DDict must be freed before dictBuffer) */
180ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize)
181{
182 ZSTD_customMem const allocator = { NULL, NULL, NULL };
183 return ZSTD_createDDict_advanced(dictBuffer, dictSize, ZSTD_dlm_byRef, ZSTD_dct_auto, allocator);
184}
185
186
187const ZSTD_DDict* ZSTD_initStaticDDict(
188 void* sBuffer, size_t sBufferSize,
189 const void* dict, size_t dictSize,
190 ZSTD_dictLoadMethod_e dictLoadMethod,
191 ZSTD_dictContentType_e dictContentType)
192{
193 size_t const neededSpace = sizeof(ZSTD_DDict)
194 + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
195 ZSTD_DDict* const ddict = (ZSTD_DDict*)sBuffer;
196 assert(sBuffer != NULL);
197 assert(dict != NULL);
198 if ((size_t)sBuffer & 7) return NULL; /* 8-aligned */
199 if (sBufferSize < neededSpace) return NULL;
200 if (dictLoadMethod == ZSTD_dlm_byCopy) {
201 ZSTD_memcpy(ddict+1, dict, dictSize); /* local copy */
202 dict = ddict+1;
203 }
204 if (ZSTD_isError( ZSTD_initDDict_internal(ddict,
205 dict, dictSize,
206 ZSTD_dlm_byRef, dictContentType) ))
207 return NULL;
208 return ddict;
209}
210
211
212size_t ZSTD_freeDDict(ZSTD_DDict* ddict)
213{
214 if (ddict==NULL) return 0; /* support free on NULL */
215 { ZSTD_customMem const cMem = ddict->cMem;
216 ZSTD_customFree(ddict->dictBuffer, cMem);
217 ZSTD_customFree(ddict, cMem);
218 return 0;
219 }
220}
221
222/*! ZSTD_estimateDDictSize() :
223 * Estimate amount of memory that will be needed to create a dictionary for decompression.
224 * Note : dictionary created by reference using ZSTD_dlm_byRef are smaller */
225size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod)
226{
227 return sizeof(ZSTD_DDict) + (dictLoadMethod == ZSTD_dlm_byRef ? 0 : dictSize);
228}
229
230size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict)
231{
232 if (ddict==NULL) return 0; /* support sizeof on NULL */
233 return sizeof(*ddict) + (ddict->dictBuffer ? ddict->dictSize : 0) ;
234}
235
236/*! ZSTD_getDictID_fromDDict() :
237 * Provides the dictID of the dictionary loaded into `ddict`.
238 * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
239 * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
240unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict)
241{
242 if (ddict==NULL) return 0;
243 return ddict->dictID;
244}
245