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
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
79typedef struct {
80    ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)];    /* Note : Space reserved for FSE Tables */
81    ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)];   /* is also used as temporary workspace while building hufTable during DDict creation */
82    ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)];    /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */
83    HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)];  /* can accommodate HUF_decompress4X */
84    U32 rep[ZSTD_REP_NUM];
85    U32 workspace[ZSTD_BUILD_FSE_TABLE_WKSP_SIZE_U32];
86} ZSTD_entropyDTables_t;
87
88typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
89               ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock,
90               ZSTDds_decompressLastBlock, ZSTDds_checkChecksum,
91               ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage;
92
93typedef enum { zdss_init=0, zdss_loadHeader,
94               zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
95
96typedef enum {
97    ZSTD_use_indefinitely = -1,  /* Use the dictionary indefinitely */
98    ZSTD_dont_use = 0,           /* Do not use the dictionary (if one exists free it) */
99    ZSTD_use_once = 1            /* Use the dictionary once and set to ZSTD_dont_use */
100} ZSTD_dictUses_e;
101
102/* Hashset for storing references to multiple ZSTD_DDict within ZSTD_DCtx */
103typedef struct {
104    const ZSTD_DDict** ddictPtrTable;
105    size_t ddictPtrTableSize;
106    size_t ddictPtrCount;
107} ZSTD_DDictHashSet;
108
109#ifndef ZSTD_DECODER_INTERNAL_BUFFER
110#  define ZSTD_DECODER_INTERNAL_BUFFER  (1 << 16)
111#endif
112
113#define ZSTD_LBMIN 64
114#define ZSTD_LBMAX (128 << 10)
115
116/* extra buffer, compensates when dst is not large enough to store litBuffer */
117#define ZSTD_LITBUFFEREXTRASIZE  BOUNDED(ZSTD_LBMIN, ZSTD_DECODER_INTERNAL_BUFFER, ZSTD_LBMAX)
118
119typedef enum {
120    ZSTD_not_in_dst = 0,  /* Stored entirely within litExtraBuffer */
121    ZSTD_in_dst = 1,           /* Stored entirely within dst (in memory after current output write) */
122    ZSTD_split = 2            /* Split between litExtraBuffer and dst */
123} ZSTD_litLocation_e;
124
125struct ZSTD_DCtx_s
126{
127    const ZSTD_seqSymbol* LLTptr;
128    const ZSTD_seqSymbol* MLTptr;
129    const ZSTD_seqSymbol* OFTptr;
130    const HUF_DTable* HUFptr;
131    ZSTD_entropyDTables_t entropy;
132    U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];   /* space needed when building huffman tables */
133    const void* previousDstEnd;   /* detect continuity */
134    const void* prefixStart;      /* start of current segment */
135    const void* virtualStart;     /* virtual start of previous segment if it was just before current one */
136    const void* dictEnd;          /* end of previous segment */
137    size_t expected;
138    ZSTD_frameHeader fParams;
139    U64 processedCSize;
140    U64 decodedSize;
141    blockType_e bType;            /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */
142    ZSTD_dStage stage;
143    U32 litEntropy;
144    U32 fseEntropy;
145    struct xxh64_state xxhState;
146    size_t headerSize;
147    ZSTD_format_e format;
148    ZSTD_forceIgnoreChecksum_e forceIgnoreChecksum;   /* User specified: if == 1, will ignore checksums in compressed frame. Default == 0 */
149    U32 validateChecksum;         /* if == 1, will validate checksum. Is == 1 if (fParams.checksumFlag == 1) and (forceIgnoreChecksum == 0). */
150    const BYTE* litPtr;
151    ZSTD_customMem customMem;
152    size_t litSize;
153    size_t rleSize;
154    size_t staticSize;
155#if DYNAMIC_BMI2 != 0
156    int bmi2;                     /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
157#endif
158
159    /* dictionary */
160    ZSTD_DDict* ddictLocal;
161    const ZSTD_DDict* ddict;     /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */
162    U32 dictID;
163    int ddictIsCold;             /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */
164    ZSTD_dictUses_e dictUses;
165    ZSTD_DDictHashSet* ddictSet;                    /* Hash set for multiple ddicts */
166    ZSTD_refMultipleDDicts_e refMultipleDDicts;     /* User specified: if == 1, will allow references to multiple DDicts. Default == 0 (disabled) */
167
168    /* streaming */
169    ZSTD_dStreamStage streamStage;
170    char*  inBuff;
171    size_t inBuffSize;
172    size_t inPos;
173    size_t maxWindowSize;
174    char*  outBuff;
175    size_t outBuffSize;
176    size_t outStart;
177    size_t outEnd;
178    size_t lhSize;
179    U32 hostageByte;
180    int noForwardProgress;
181    ZSTD_bufferMode_e outBufferMode;
182    ZSTD_outBuffer expectedOutBuffer;
183
184    /* workspace */
185    BYTE* litBuffer;
186    const BYTE* litBufferEnd;
187    ZSTD_litLocation_e litBufferLocation;
188    BYTE litExtraBuffer[ZSTD_LITBUFFEREXTRASIZE + WILDCOPY_OVERLENGTH]; /* literal buffer can be split between storage within dst and within this scratch buffer */
189    BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
190
191    size_t oversizedDuration;
192
193#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
194    void const* dictContentBeginForFuzzing;
195    void const* dictContentEndForFuzzing;
196#endif
197
198    /* Tracing */
199};  /* typedef'd to ZSTD_DCtx within "zstd.h" */
200
201MEM_STATIC int ZSTD_DCtx_get_bmi2(const struct ZSTD_DCtx_s *dctx) {
202#if DYNAMIC_BMI2 != 0
203	return dctx->bmi2;
204#else
205    (void)dctx;
206	return 0;
207#endif
208}
209
210/*-*******************************************************
211 *  Shared internal functions
212 *********************************************************/
213
214/*! ZSTD_loadDEntropy() :
215 *  dict : must point at beginning of a valid zstd dictionary.
216 * @return : size of dictionary header (size of magic number + dict ID + entropy tables) */
217size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
218                   const void* const dict, size_t const dictSize);
219
220/*! ZSTD_checkContinuity() :
221 *  check if next `dst` follows previous position, where decompression ended.
222 *  If yes, do nothing (continue on current segment).
223 *  If not, classify previous segment as "external dictionary", and start a new segment.
224 *  This function cannot fail. */
225void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize);
226
227
228#endif /* ZSTD_DECOMPRESS_INTERNAL_H */
229