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_decompress_internal:
12 * objects and definitions shared within lib/decompress modules */
13
14 #ifndef ZSTD_DECOMPRESS_INTERNAL_H
15 #define ZSTD_DECOMPRESS_INTERNAL_H
16
17 /*-*******************************************************
18 * Dependencies
19 *********************************************************/
20 #include "../common/mem.h" /* BYTE, U16, U32 */
21 #include "../common/zstd_internal.h" /* constants : MaxLL, MaxML, MaxOff, LLFSELog, etc. */
22
23 /*-*******************************************************
24 * Constants
25 *********************************************************/
26 static UNUSED_ATTR const U32 LL_base[MaxLL+1] = {
27 0, 1, 2, 3, 4, 5, 6, 7,
28 8, 9, 10, 11, 12, 13, 14, 15,
29 16, 18, 20, 22, 24, 28, 32, 40,
30 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000,
31 0x2000, 0x4000, 0x8000, 0x10000 };
32
33 static UNUSED_ATTR const U32 OF_base[MaxOff+1] = {
34 0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D,
35 0xFD, 0x1FD, 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD,
36 0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD,
37 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD };
38
39 static UNUSED_ATTR const U8 OF_bits[MaxOff+1] = {
40 0, 1, 2, 3, 4, 5, 6, 7,
41 8, 9, 10, 11, 12, 13, 14, 15,
42 16, 17, 18, 19, 20, 21, 22, 23,
43 24, 25, 26, 27, 28, 29, 30, 31 };
44
45 static UNUSED_ATTR const U32 ML_base[MaxML+1] = {
46 3, 4, 5, 6, 7, 8, 9, 10,
47 11, 12, 13, 14, 15, 16, 17, 18,
48 19, 20, 21, 22, 23, 24, 25, 26,
49 27, 28, 29, 30, 31, 32, 33, 34,
50 35, 37, 39, 41, 43, 47, 51, 59,
51 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803,
52 0x1003, 0x2003, 0x4003, 0x8003, 0x10003 };
53
54 /*-*******************************************************
55 * Decompression types
56 *********************************************************/
57 typedef struct {
58 U32 fastMode;
59 U32 tableLog;
60 } ZSTD_seqSymbol_header;
61
62 typedef struct {
63 U16 nextState;
64 BYTE nbAdditionalBits;
65 BYTE nbBits;
66 U32 baseValue;
67 } ZSTD_seqSymbol;
68
69 #define SEQSYMBOL_TABLE_SIZE(log) (1 + (1 << (log)))
70
71 #define ZSTD_BUILD_FSE_TABLE_WKSP_SIZE (sizeof(S16) * (MaxSeq + 1) + (1u << MaxFSELog) + sizeof(U64))
72 #define ZSTD_BUILD_FSE_TABLE_WKSP_SIZE_U32 ((ZSTD_BUILD_FSE_TABLE_WKSP_SIZE + sizeof(U32) - 1) / sizeof(U32))
73
74 typedef struct {
75 ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)]; /* Note : Space reserved for FSE Tables */
76 ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)]; /* is also used as temporary workspace while building hufTable during DDict creation */
77 ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)]; /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */
78 HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)]; /* can accommodate HUF_decompress4X */
79 U32 rep[ZSTD_REP_NUM];
80 U32 workspace[ZSTD_BUILD_FSE_TABLE_WKSP_SIZE_U32];
81 } ZSTD_entropyDTables_t;
82
83 typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
84 ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock,
85 ZSTDds_decompressLastBlock, ZSTDds_checkChecksum,
86 ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage;
87
88 typedef enum { zdss_init=0, zdss_loadHeader,
89 zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
90
91 typedef enum {
92 ZSTD_use_indefinitely = -1, /* Use the dictionary indefinitely */
93 ZSTD_dont_use = 0, /* Do not use the dictionary (if one exists free it) */
94 ZSTD_use_once = 1 /* Use the dictionary once and set to ZSTD_dont_use */
95 } ZSTD_dictUses_e;
96
97 /* Hashset for storing references to multiple ZSTD_DDict within ZSTD_DCtx */
98 typedef struct {
99 const ZSTD_DDict** ddictPtrTable;
100 size_t ddictPtrTableSize;
101 size_t ddictPtrCount;
102 } ZSTD_DDictHashSet;
103
104 #ifndef ZSTD_DECODER_INTERNAL_BUFFER
105 # define ZSTD_DECODER_INTERNAL_BUFFER (1 << 16)
106 #endif
107
108 #define ZSTD_LBMIN 64
109 #define ZSTD_LBMAX (128 << 10)
110
111 /* extra buffer, compensates when dst is not large enough to store litBuffer */
112 #define ZSTD_LITBUFFEREXTRASIZE BOUNDED(ZSTD_LBMIN, ZSTD_DECODER_INTERNAL_BUFFER, ZSTD_LBMAX)
113
114 typedef enum {
115 ZSTD_not_in_dst = 0, /* Stored entirely within litExtraBuffer */
116 ZSTD_in_dst = 1, /* Stored entirely within dst (in memory after current output write) */
117 ZSTD_split = 2 /* Split between litExtraBuffer and dst */
118 } ZSTD_litLocation_e;
119
120 struct ZSTD_DCtx_s
121 {
122 const ZSTD_seqSymbol* LLTptr;
123 const ZSTD_seqSymbol* MLTptr;
124 const ZSTD_seqSymbol* OFTptr;
125 const HUF_DTable* HUFptr;
126 ZSTD_entropyDTables_t entropy;
127 U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32]; /* space needed when building huffman tables */
128 const void* previousDstEnd; /* detect continuity */
129 const void* prefixStart; /* start of current segment */
130 const void* virtualStart; /* virtual start of previous segment if it was just before current one */
131 const void* dictEnd; /* end of previous segment */
132 size_t expected;
133 ZSTD_frameHeader fParams;
134 U64 processedCSize;
135 U64 decodedSize;
136 blockType_e bType; /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */
137 ZSTD_dStage stage;
138 U32 litEntropy;
139 U32 fseEntropy;
140 struct xxh64_state xxhState;
141 size_t headerSize;
142 ZSTD_format_e format;
143 ZSTD_forceIgnoreChecksum_e forceIgnoreChecksum; /* User specified: if == 1, will ignore checksums in compressed frame. Default == 0 */
144 U32 validateChecksum; /* if == 1, will validate checksum. Is == 1 if (fParams.checksumFlag == 1) and (forceIgnoreChecksum == 0). */
145 const BYTE* litPtr;
146 ZSTD_customMem customMem;
147 size_t litSize;
148 size_t rleSize;
149 size_t staticSize;
150 #if DYNAMIC_BMI2 != 0
151 int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
152 #endif
153
154 /* dictionary */
155 ZSTD_DDict* ddictLocal;
156 const ZSTD_DDict* ddict; /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */
157 U32 dictID;
158 int ddictIsCold; /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */
159 ZSTD_dictUses_e dictUses;
160 ZSTD_DDictHashSet* ddictSet; /* Hash set for multiple ddicts */
161 ZSTD_refMultipleDDicts_e refMultipleDDicts; /* User specified: if == 1, will allow references to multiple DDicts. Default == 0 (disabled) */
162
163 /* streaming */
164 ZSTD_dStreamStage streamStage;
165 char* inBuff;
166 size_t inBuffSize;
167 size_t inPos;
168 size_t maxWindowSize;
169 char* outBuff;
170 size_t outBuffSize;
171 size_t outStart;
172 size_t outEnd;
173 size_t lhSize;
174 U32 hostageByte;
175 int noForwardProgress;
176 ZSTD_bufferMode_e outBufferMode;
177 ZSTD_outBuffer expectedOutBuffer;
178
179 /* workspace */
180 BYTE* litBuffer;
181 const BYTE* litBufferEnd;
182 ZSTD_litLocation_e litBufferLocation;
183 BYTE litExtraBuffer[ZSTD_LITBUFFEREXTRASIZE + WILDCOPY_OVERLENGTH]; /* literal buffer can be split between storage within dst and within this scratch buffer */
184 BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
185
186 size_t oversizedDuration;
187
188 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
189 void const* dictContentBeginForFuzzing;
190 void const* dictContentEndForFuzzing;
191 #endif
192
193 /* Tracing */
194 }; /* typedef'd to ZSTD_DCtx within "zstd.h" */
195
ZSTD_DCtx_get_bmi2(const struct ZSTD_DCtx_s * dctx)196 MEM_STATIC int ZSTD_DCtx_get_bmi2(const struct ZSTD_DCtx_s *dctx) {
197 #if DYNAMIC_BMI2 != 0
198 return dctx->bmi2;
199 #else
200 (void)dctx;
201 return 0;
202 #endif
203 }
204
205 /*-*******************************************************
206 * Shared internal functions
207 *********************************************************/
208
209 /*! ZSTD_loadDEntropy() :
210 * dict : must point at beginning of a valid zstd dictionary.
211 * @return : size of dictionary header (size of magic number + dict ID + entropy tables) */
212 size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
213 const void* const dict, size_t const dictSize);
214
215 /*! ZSTD_checkContinuity() :
216 * check if next `dst` follows previous position, where decompression ended.
217 * If yes, do nothing (continue on current segment).
218 * If not, classify previous segment as "external dictionary", and start a new segment.
219 * This function cannot fail. */
220 void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize);
221
222 #endif /* ZSTD_DECOMPRESS_INTERNAL_H */
223