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
12/* zstd_decompress_internal:
13 * objects and definitions shared within lib/decompress modules */
14
15 #ifndef ZSTD_DECOMPRESS_INTERNAL_H
16 #define ZSTD_DECOMPRESS_INTERNAL_H
17
18
19/*-*******************************************************
20 * Dependencies
21 *********************************************************/
22#include "../common/mem.h" /* BYTE, U16, U32 */
23#include "../common/zstd_internal.h" /* constants : MaxLL, MaxML, MaxOff, LLFSELog, etc. */
24
25
26
27/*-*******************************************************
28 * Constants
29 *********************************************************/
30static UNUSED_ATTR const U32 LL_base[MaxLL+1] = {
31 0, 1, 2, 3, 4, 5, 6, 7,
32 8, 9, 10, 11, 12, 13, 14, 15,
33 16, 18, 20, 22, 24, 28, 32, 40,
34 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000,
35 0x2000, 0x4000, 0x8000, 0x10000 };
36
37static UNUSED_ATTR const U32 OF_base[MaxOff+1] = {
38 0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D,
39 0xFD, 0x1FD, 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD,
40 0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD,
41 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD };
42
43static UNUSED_ATTR const U8 OF_bits[MaxOff+1] = {
44 0, 1, 2, 3, 4, 5, 6, 7,
45 8, 9, 10, 11, 12, 13, 14, 15,
46 16, 17, 18, 19, 20, 21, 22, 23,
47 24, 25, 26, 27, 28, 29, 30, 31 };
48
49static UNUSED_ATTR const U32 ML_base[MaxML+1] = {
50 3, 4, 5, 6, 7, 8, 9, 10,
51 11, 12, 13, 14, 15, 16, 17, 18,
52 19, 20, 21, 22, 23, 24, 25, 26,
53 27, 28, 29, 30, 31, 32, 33, 34,
54 35, 37, 39, 41, 43, 47, 51, 59,
55 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803,
56 0x1003, 0x2003, 0x4003, 0x8003, 0x10003 };
57
58
59/*-*******************************************************
60 * Decompression types
61 *********************************************************/
62 typedef struct {
63 U32 fastMode;
64 U32 tableLog;
65 } ZSTD_seqSymbol_header;
66
67 typedef struct {
68 U16 nextState;
69 BYTE nbAdditionalBits;
70 BYTE nbBits;
71 U32 baseValue;
72 } ZSTD_seqSymbol;
73
74 #define SEQSYMBOL_TABLE_SIZE(log) (1 + (1 << (log)))
75
76#define ZSTD_BUILD_FSE_TABLE_WKSP_SIZE (sizeof(S16) * (MaxSeq + 1) + (1u << MaxFSELog) + sizeof(U64))
77#define ZSTD_BUILD_FSE_TABLE_WKSP_SIZE_U32 ((ZSTD_BUILD_FSE_TABLE_WKSP_SIZE + sizeof(U32) - 1) / sizeof(U32))
78#define ZSTD_HUFFDTABLE_CAPACITY_LOG 12
79
80typedef struct {
81 ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)]; /* Note : Space reserved for FSE Tables */
82 ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)]; /* is also used as temporary workspace while building hufTable during DDict creation */
83 ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)]; /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */
84 HUF_DTable hufTable[HUF_DTABLE_SIZE(ZSTD_HUFFDTABLE_CAPACITY_LOG)]; /* can accommodate HUF_decompress4X */
85 U32 rep[ZSTD_REP_NUM];
86 U32 workspace[ZSTD_BUILD_FSE_TABLE_WKSP_SIZE_U32];
87} ZSTD_entropyDTables_t;
88
89typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
90 ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock,
91 ZSTDds_decompressLastBlock, ZSTDds_checkChecksum,
92 ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage;
93
94typedef enum { zdss_init=0, zdss_loadHeader,
95 zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
96
97typedef enum {
98 ZSTD_use_indefinitely = -1, /* Use the dictionary indefinitely */
99 ZSTD_dont_use = 0, /* Do not use the dictionary (if one exists free it) */
100 ZSTD_use_once = 1 /* Use the dictionary once and set to ZSTD_dont_use */
101} ZSTD_dictUses_e;
102
103/* Hashset for storing references to multiple ZSTD_DDict within ZSTD_DCtx */
104typedef struct {
105 const ZSTD_DDict** ddictPtrTable;
106 size_t ddictPtrTableSize;
107 size_t ddictPtrCount;
108} ZSTD_DDictHashSet;
109
110#ifndef ZSTD_DECODER_INTERNAL_BUFFER
111# define ZSTD_DECODER_INTERNAL_BUFFER (1 << 16)
112#endif
113
114#define ZSTD_LBMIN 64
115#define ZSTD_LBMAX (128 << 10)
116
117/* extra buffer, compensates when dst is not large enough to store litBuffer */
118#define ZSTD_LITBUFFEREXTRASIZE BOUNDED(ZSTD_LBMIN, ZSTD_DECODER_INTERNAL_BUFFER, ZSTD_LBMAX)
119
120typedef enum {
121 ZSTD_not_in_dst = 0, /* Stored entirely within litExtraBuffer */
122 ZSTD_in_dst = 1, /* Stored entirely within dst (in memory after current output write) */
123 ZSTD_split = 2 /* Split between litExtraBuffer and dst */
124} ZSTD_litLocation_e;
125
126struct ZSTD_DCtx_s
127{
128 const ZSTD_seqSymbol* LLTptr;
129 const ZSTD_seqSymbol* MLTptr;
130 const ZSTD_seqSymbol* OFTptr;
131 const HUF_DTable* HUFptr;
132 ZSTD_entropyDTables_t entropy;
133 U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32]; /* space needed when building huffman tables */
134 const void* previousDstEnd; /* detect continuity */
135 const void* prefixStart; /* start of current segment */
136 const void* virtualStart; /* virtual start of previous segment if it was just before current one */
137 const void* dictEnd; /* end of previous segment */
138 size_t expected;
139 ZSTD_frameHeader fParams;
140 U64 processedCSize;
141 U64 decodedSize;
142 blockType_e bType; /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */
143 ZSTD_dStage stage;
144 U32 litEntropy;
145 U32 fseEntropy;
146 XXH64_state_t xxhState;
147 size_t headerSize;
148 ZSTD_format_e format;
149 ZSTD_forceIgnoreChecksum_e forceIgnoreChecksum; /* User specified: if == 1, will ignore checksums in compressed frame. Default == 0 */
150 U32 validateChecksum; /* if == 1, will validate checksum. Is == 1 if (fParams.checksumFlag == 1) and (forceIgnoreChecksum == 0). */
151 const BYTE* litPtr;
152 ZSTD_customMem customMem;
153 size_t litSize;
154 size_t rleSize;
155 size_t staticSize;
156#if DYNAMIC_BMI2 != 0
157 int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
158#endif
159
160 /* dictionary */
161 ZSTD_DDict* ddictLocal;
162 const ZSTD_DDict* ddict; /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */
163 U32 dictID;
164 int ddictIsCold; /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */
165 ZSTD_dictUses_e dictUses;
166 ZSTD_DDictHashSet* ddictSet; /* Hash set for multiple ddicts */
167 ZSTD_refMultipleDDicts_e refMultipleDDicts; /* User specified: if == 1, will allow references to multiple DDicts. Default == 0 (disabled) */
168 int disableHufAsm;
169
170 /* streaming */
171 ZSTD_dStreamStage streamStage;
172 char* inBuff;
173 size_t inBuffSize;
174 size_t inPos;
175 size_t maxWindowSize;
176 char* outBuff;
177 size_t outBuffSize;
178 size_t outStart;
179 size_t outEnd;
180 size_t lhSize;
181#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
182 void* legacyContext;
183 U32 previousLegacyVersion;
184 U32 legacyVersion;
185#endif
186 U32 hostageByte;
187 int noForwardProgress;
188 ZSTD_bufferMode_e outBufferMode;
189 ZSTD_outBuffer expectedOutBuffer;
190
191 /* workspace */
192 BYTE* litBuffer;
193 const BYTE* litBufferEnd;
194 ZSTD_litLocation_e litBufferLocation;
195 BYTE litExtraBuffer[ZSTD_LITBUFFEREXTRASIZE + WILDCOPY_OVERLENGTH]; /* literal buffer can be split between storage within dst and within this scratch buffer */
196 BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
197
198 size_t oversizedDuration;
199
200#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
201 void const* dictContentBeginForFuzzing;
202 void const* dictContentEndForFuzzing;
203#endif
204
205 /* Tracing */
206#if ZSTD_TRACE
207 ZSTD_TraceCtx traceCtx;
208#endif
209}; /* typedef'd to ZSTD_DCtx within "zstd.h" */
210
211MEM_STATIC int ZSTD_DCtx_get_bmi2(const struct ZSTD_DCtx_s *dctx) {
212#if DYNAMIC_BMI2 != 0
213 return dctx->bmi2;
214#else
215 (void)dctx;
216 return 0;
217#endif
218}
219
220/*-*******************************************************
221 * Shared internal functions
222 *********************************************************/
223
224/*! ZSTD_loadDEntropy() :
225 * dict : must point at beginning of a valid zstd dictionary.
226 * @return : size of dictionary header (size of magic number + dict ID + entropy tables) */
227size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
228 const void* const dict, size_t const dictSize);
229
230/*! ZSTD_checkContinuity() :
231 * check if next `dst` follows previous position, where decompression ended.
232 * If yes, do nothing (continue on current segment).
233 * If not, classify previous segment as "external dictionary", and start a new segment.
234 * This function cannot fail. */
235void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize);
236
237
238#endif /* ZSTD_DECOMPRESS_INTERNAL_H */
239