root/lib/zstd/compress.c

DEFINITIONS

1. ZSTD_compressBound
2. ZSTD_resetSeqStore
3. ZSTD_CCtxWorkspaceBound
4. ZSTD_createCCtx_advanced
5. ZSTD_initCCtx
6. ZSTD_freeCCtx
7. ZSTD_getSeqStore
8. ZSTD_getParamsFromCCtx
9. ZSTD_checkCParams
10. ZSTD_cycleLog
11. ZSTD_adjustCParams
12. ZSTD_equivalentParams
13. ZSTD_continueCCtx
14. ZSTD_resetCCtx_advanced
15. ZSTD_invalidateRepCodes
16. ZSTD_copyCCtx
17. ZSTD_reduceTable
18. ZSTD_reduceIndex
19. ZSTD_noCompressBlock
20. ZSTD_noCompressLiterals
21. ZSTD_compressRleLiteralsBlock
22. ZSTD_minGain
23. ZSTD_compressLiterals
24. ZSTD_seqToCodes
25. ZSTD_compressSequences_internal
26. ZSTD_compressSequences
27. ZSTD_storeSeq
28. ZSTD_NbCommonBytes
29. ZSTD_count
30. ZSTD_count_2segments
31. ZSTD_hash3
32. ZSTD_hash3Ptr
33. ZSTD_hash4
34. ZSTD_hash4Ptr
35. ZSTD_hash5
36. ZSTD_hash5Ptr
37. ZSTD_hash6
38. ZSTD_hash6Ptr
39. ZSTD_hash7
40. ZSTD_hash7Ptr
41. ZSTD_hash8
42. ZSTD_hash8Ptr
43. ZSTD_hashPtr
44. ZSTD_fillHashTable
45. ZSTD_compressBlock_fast_generic
46. ZSTD_compressBlock_fast
47. ZSTD_compressBlock_fast_extDict_generic
48. ZSTD_compressBlock_fast_extDict
49. ZSTD_fillDoubleHashTable
50. ZSTD_compressBlock_doubleFast_generic
51. ZSTD_compressBlock_doubleFast
52. ZSTD_compressBlock_doubleFast_extDict_generic
53. ZSTD_compressBlock_doubleFast_extDict
54. ZSTD_insertBt1
55. ZSTD_insertBtAndFindBestMatch
56. ZSTD_updateTree
57. ZSTD_BtFindBestMatch
58. ZSTD_BtFindBestMatch_selectMLS
59. ZSTD_updateTree_extDict
60. ZSTD_BtFindBestMatch_extDict
61. ZSTD_BtFindBestMatch_selectMLS_extDict
62. ZSTD_insertAndFindFirstIndex
63. ZSTD_HcFindBestMatch_generic
64. ZSTD_HcFindBestMatch_selectMLS
65. ZSTD_HcFindBestMatch_extDict_selectMLS
66. ZSTD_compressBlock_lazy_generic
67. ZSTD_compressBlock_btlazy2
68. ZSTD_compressBlock_lazy2
69. ZSTD_compressBlock_lazy
70. ZSTD_compressBlock_greedy
71. ZSTD_compressBlock_lazy_extDict_generic
72. ZSTD_compressBlock_greedy_extDict
73. ZSTD_compressBlock_lazy_extDict
74. ZSTD_compressBlock_lazy2_extDict
75. ZSTD_compressBlock_btlazy2_extDict
76. ZSTD_compressBlock_btopt
77. ZSTD_compressBlock_btopt2
78. ZSTD_compressBlock_btopt_extDict
79. ZSTD_compressBlock_btopt2_extDict
80. ZSTD_selectBlockCompressor
81. ZSTD_compressBlock_internal
82. ZSTD_compress_generic
83. ZSTD_writeFrameHeader
84. ZSTD_compressContinue_internal
85. ZSTD_compressContinue
86. ZSTD_getBlockSizeMax
87. ZSTD_compressBlock
88. ZSTD_loadDictionaryContent
89. ZSTD_checkDictNCount
90. ZSTD_loadZstdDictionary
91. ZSTD_compress_insertDictionary
92. ZSTD_compressBegin_internal
93. ZSTD_compressBegin_advanced
94. ZSTD_compressBegin_usingDict
95. ZSTD_compressBegin
96. ZSTD_writeEpilogue
97. ZSTD_compressEnd
98. ZSTD_compress_internal
99. ZSTD_compress_usingDict
100. ZSTD_compressCCtx
101. ZSTD_CDictWorkspaceBound
102. ZSTD_createCDict_advanced
103. ZSTD_initCDict
104. ZSTD_freeCDict
105. ZSTD_getParamsFromCDict
106. ZSTD_compressBegin_usingCDict
107. ZSTD_compress_usingCDict
108. ZSTD_CStreamWorkspaceBound
109. ZSTD_createCStream_advanced
110. ZSTD_freeCStream
111. ZSTD_CStreamInSize
112. ZSTD_CStreamOutSize
113. ZSTD_resetCStream_internal
114. ZSTD_resetCStream
115. ZSTD_initCStream_advanced
116. ZSTD_initCStream
117. ZSTD_initCStream_usingCDict
118. ZSTD_limitCopy
119. ZSTD_compressStream_generic
120. ZSTD_compressStream
121. ZSTD_flushStream
122. ZSTD_endStream
123. ZSTD_maxCLevel
124. ZSTD_getCParams
125. ZSTD_getParams

   1 /**
   2  * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under the BSD-style license found in the
   6  * LICENSE file in the root directory of https://github.com/facebook/zstd.
   7  * An additional grant of patent rights can be found in the PATENTS file in the
   8  * same directory.
   9  *
  10  * This program is free software; you can redistribute it and/or modify it under
  11  * the terms of the GNU General Public License version 2 as published by the
  12  * Free Software Foundation. This program is dual-licensed; you may select
  13  * either version 2 of the GNU General Public License ("GPL") or BSD license
  14  * ("BSD").
  15  */
  16 
  17 /*-*************************************
  18 *  Dependencies
  19 ***************************************/
  20 #include "fse.h"
  21 #include "huf.h"
  22 #include "mem.h"
  23 #include "zstd_internal.h" /* includes zstd.h */
  24 #include <linux/kernel.h>
  25 #include <linux/module.h>
  26 #include <linux/string.h> /* memset */
  27 
  28 /*-*************************************
  29 *  Constants
  30 ***************************************/
  31 static const U32 g_searchStrength = 8; /* control skip over incompressible data */
  32 #define HASH_READ_SIZE 8
  33 typedef enum { ZSTDcs_created = 0, ZSTDcs_init, ZSTDcs_ongoing, ZSTDcs_ending } ZSTD_compressionStage_e;
  34 
  35 /*-*************************************
  36 *  Helper functions
  37 ***************************************/
  38 size_t ZSTD_compressBound(size_t srcSize) { return FSE_compressBound(srcSize) + 12; }
  39 
  40 /*-*************************************
  41 *  Sequence storage
  42 ***************************************/
  43 static void ZSTD_resetSeqStore(seqStore_t *ssPtr)
  44 {
  45         ssPtr->lit = ssPtr->litStart;
  46         ssPtr->sequences = ssPtr->sequencesStart;
  47         ssPtr->longLengthID = 0;
  48 }
  49 
  50 /*-*************************************
  51 *  Context memory management
  52 ***************************************/
  53 struct ZSTD_CCtx_s {
  54         const BYTE *nextSrc;  /* next block here to continue on curr prefix */
  55         const BYTE *base;     /* All regular indexes relative to this position */
  56         const BYTE *dictBase; /* extDict indexes relative to this position */
  57         U32 dictLimit;  /* below that point, need extDict */
  58         U32 lowLimit;    /* below that point, no more data */
  59         U32 nextToUpdate;     /* index from which to continue dictionary update */
  60         U32 nextToUpdate3;    /* index from which to continue dictionary update */
  61         U32 hashLog3;    /* dispatch table : larger == faster, more memory */
  62         U32 loadedDictEnd;    /* index of end of dictionary */
  63         U32 forceWindow;      /* force back-references to respect limit of 1<<wLog, even for dictionary */
  64         U32 forceRawDict;     /* Force loading dictionary in "content-only" mode (no header analysis) */
  65         ZSTD_compressionStage_e stage;
  66         U32 rep[ZSTD_REP_NUM];
  67         U32 repToConfirm[ZSTD_REP_NUM];
  68         U32 dictID;
  69         ZSTD_parameters params;
  70         void *workSpace;
  71         size_t workSpaceSize;
  72         size_t blockSize;
  73         U64 frameContentSize;
  74         struct xxh64_state xxhState;
  75         ZSTD_customMem customMem;
  76 
  77         seqStore_t seqStore; /* sequences storage ptrs */
  78         U32 *hashTable;
  79         U32 *hashTable3;
  80         U32 *chainTable;
  81         HUF_CElt *hufTable;
  82         U32 flagStaticTables;
  83         HUF_repeat flagStaticHufTable;
  84         FSE_CTable offcodeCTable[FSE_CTABLE_SIZE_U32(OffFSELog, MaxOff)];
  85         FSE_CTable matchlengthCTable[FSE_CTABLE_SIZE_U32(MLFSELog, MaxML)];
  86         FSE_CTable litlengthCTable[FSE_CTABLE_SIZE_U32(LLFSELog, MaxLL)];
  87         unsigned tmpCounters[HUF_COMPRESS_WORKSPACE_SIZE_U32];
  88 };
  89 
  90 size_t ZSTD_CCtxWorkspaceBound(ZSTD_compressionParameters cParams)
  91 {
  92         size_t const blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, (size_t)1 << cParams.windowLog);
  93         U32 const divider = (cParams.searchLength == 3) ? 3 : 4;
  94         size_t const maxNbSeq = blockSize / divider;
  95         size_t const tokenSpace = blockSize + 11 * maxNbSeq;
  96         size_t const chainSize = (cParams.strategy == ZSTD_fast) ? 0 : (1 << cParams.chainLog);
  97         size_t const hSize = ((size_t)1) << cParams.hashLog;
  98         U32 const hashLog3 = (cParams.searchLength > 3) ? 0 : MIN(ZSTD_HASHLOG3_MAX, cParams.windowLog);
  99         size_t const h3Size = ((size_t)1) << hashLog3;
 100         size_t const tableSpace = (chainSize + hSize + h3Size) * sizeof(U32);
 101         size_t const optSpace =
 102             ((MaxML + 1) + (MaxLL + 1) + (MaxOff + 1) + (1 << Litbits)) * sizeof(U32) + (ZSTD_OPT_NUM + 1) * (sizeof(ZSTD_match_t) + sizeof(ZSTD_optimal_t));
 103         size_t const workspaceSize = tableSpace + (256 * sizeof(U32)) /* huffTable */ + tokenSpace +
 104                                      (((cParams.strategy == ZSTD_btopt) || (cParams.strategy == ZSTD_btopt2)) ? optSpace : 0);
 105 
 106         return ZSTD_ALIGN(sizeof(ZSTD_stack)) + ZSTD_ALIGN(sizeof(ZSTD_CCtx)) + ZSTD_ALIGN(workspaceSize);
 107 }
 108 
 109 static ZSTD_CCtx *ZSTD_createCCtx_advanced(ZSTD_customMem customMem)
 110 {
 111         ZSTD_CCtx *cctx;
 112         if (!customMem.customAlloc || !customMem.customFree)
 113                 return NULL;
 114         cctx = (ZSTD_CCtx *)ZSTD_malloc(sizeof(ZSTD_CCtx), customMem);
 115         if (!cctx)
 116                 return NULL;
 117         memset(cctx, 0, sizeof(ZSTD_CCtx));
 118         cctx->customMem = customMem;
 119         return cctx;
 120 }
 121 
 122 ZSTD_CCtx *ZSTD_initCCtx(void *workspace, size_t workspaceSize)
 123 {
 124         ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
 125         ZSTD_CCtx *cctx = ZSTD_createCCtx_advanced(stackMem);
 126         if (cctx) {
 127                 cctx->workSpace = ZSTD_stackAllocAll(cctx->customMem.opaque, &cctx->workSpaceSize);
 128         }
 129         return cctx;
 130 }
 131 
 132 size_t ZSTD_freeCCtx(ZSTD_CCtx *cctx)
 133 {
 134         if (cctx == NULL)
 135                 return 0; /* support free on NULL */
 136         ZSTD_free(cctx->workSpace, cctx->customMem);
 137         ZSTD_free(cctx, cctx->customMem);
 138         return 0; /* reserved as a potential error code in the future */
 139 }
 140 
 141 const seqStore_t *ZSTD_getSeqStore(const ZSTD_CCtx *ctx) /* hidden interface */ { return &(ctx->seqStore); }
 142 
 143 static ZSTD_parameters ZSTD_getParamsFromCCtx(const ZSTD_CCtx *cctx) { return cctx->params; }
 144 
 145 /** ZSTD_checkParams() :
 146         ensure param values remain within authorized range.
 147         @return : 0, or an error code if one value is beyond authorized range */
 148 size_t ZSTD_checkCParams(ZSTD_compressionParameters cParams)
 149 {
 150 #define CLAMPCHECK(val, min, max)                                       \
 151         {                                                               \
 152                 if ((val < min) | (val > max))                          \
 153                         return ERROR(compressionParameter_unsupported); \
 154         }
 155         CLAMPCHECK(cParams.windowLog, ZSTD_WINDOWLOG_MIN, ZSTD_WINDOWLOG_MAX);
 156         CLAMPCHECK(cParams.chainLog, ZSTD_CHAINLOG_MIN, ZSTD_CHAINLOG_MAX);
 157         CLAMPCHECK(cParams.hashLog, ZSTD_HASHLOG_MIN, ZSTD_HASHLOG_MAX);
 158         CLAMPCHECK(cParams.searchLog, ZSTD_SEARCHLOG_MIN, ZSTD_SEARCHLOG_MAX);
 159         CLAMPCHECK(cParams.searchLength, ZSTD_SEARCHLENGTH_MIN, ZSTD_SEARCHLENGTH_MAX);
 160         CLAMPCHECK(cParams.targetLength, ZSTD_TARGETLENGTH_MIN, ZSTD_TARGETLENGTH_MAX);
 161         if ((U32)(cParams.strategy) > (U32)ZSTD_btopt2)
 162                 return ERROR(compressionParameter_unsupported);
 163         return 0;
 164 }
 165 
 166 /** ZSTD_cycleLog() :
 167  *  condition for correct operation : hashLog > 1 */
 168 static U32 ZSTD_cycleLog(U32 hashLog, ZSTD_strategy strat)
 169 {
 170         U32 const btScale = ((U32)strat >= (U32)ZSTD_btlazy2);
 171         return hashLog - btScale;
 172 }
 173 
 174 /** ZSTD_adjustCParams() :
 175         optimize `cPar` for a given input (`srcSize` and `dictSize`).
 176         mostly downsizing to reduce memory consumption and initialization.
 177         Both `srcSize` and `dictSize` are optional (use 0 if unknown),
 178         but if both are 0, no optimization can be done.
 179         Note : cPar is considered validated at this stage. Use ZSTD_checkParams() to ensure that. */
 180 ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize)
 181 {
 182         if (srcSize + dictSize == 0)
 183                 return cPar; /* no size information available : no adjustment */
 184 
 185         /* resize params, to use less memory when necessary */
 186         {
 187                 U32 const minSrcSize = (srcSize == 0) ? 500 : 0;
 188                 U64 const rSize = srcSize + dictSize + minSrcSize;
 189                 if (rSize < ((U64)1 << ZSTD_WINDOWLOG_MAX)) {
 190                         U32 const srcLog = MAX(ZSTD_HASHLOG_MIN, ZSTD_highbit32((U32)(rSize)-1) + 1);
 191                         if (cPar.windowLog > srcLog)
 192                                 cPar.windowLog = srcLog;
 193                 }
 194         }
 195         if (cPar.hashLog > cPar.windowLog)
 196                 cPar.hashLog = cPar.windowLog;
 197         {
 198                 U32 const cycleLog = ZSTD_cycleLog(cPar.chainLog, cPar.strategy);
 199                 if (cycleLog > cPar.windowLog)
 200                         cPar.chainLog -= (cycleLog - cPar.windowLog);
 201         }
 202 
 203         if (cPar.windowLog < ZSTD_WINDOWLOG_ABSOLUTEMIN)
 204                 cPar.windowLog = ZSTD_WINDOWLOG_ABSOLUTEMIN; /* required for frame header */
 205 
 206         return cPar;
 207 }
 208 
 209 static U32 ZSTD_equivalentParams(ZSTD_parameters param1, ZSTD_parameters param2)
 210 {
 211         return (param1.cParams.hashLog == param2.cParams.hashLog) & (param1.cParams.chainLog == param2.cParams.chainLog) &
 212                (param1.cParams.strategy == param2.cParams.strategy) & ((param1.cParams.searchLength == 3) == (param2.cParams.searchLength == 3));
 213 }
 214 
 215 /*! ZSTD_continueCCtx() :
 216         reuse CCtx without reset (note : requires no dictionary) */
 217 static size_t ZSTD_continueCCtx(ZSTD_CCtx *cctx, ZSTD_parameters params, U64 frameContentSize)
 218 {
 219         U32 const end = (U32)(cctx->nextSrc - cctx->base);
 220         cctx->params = params;
 221         cctx->frameContentSize = frameContentSize;
 222         cctx->lowLimit = end;
 223         cctx->dictLimit = end;
 224         cctx->nextToUpdate = end + 1;
 225         cctx->stage = ZSTDcs_init;
 226         cctx->dictID = 0;
 227         cctx->loadedDictEnd = 0;
 228         {
 229                 int i;
 230                 for (i = 0; i < ZSTD_REP_NUM; i++)
 231                         cctx->rep[i] = repStartValue[i];
 232         }
 233         cctx->seqStore.litLengthSum = 0; /* force reset of btopt stats */
 234         xxh64_reset(&cctx->xxhState, 0);
 235         return 0;
 236 }
 237 
 238 typedef enum { ZSTDcrp_continue, ZSTDcrp_noMemset, ZSTDcrp_fullReset } ZSTD_compResetPolicy_e;
 239 
 240 /*! ZSTD_resetCCtx_advanced() :
 241         note : `params` must be validated */
 242 static size_t ZSTD_resetCCtx_advanced(ZSTD_CCtx *zc, ZSTD_parameters params, U64 frameContentSize, ZSTD_compResetPolicy_e const crp)
 243 {
 244         if (crp == ZSTDcrp_continue)
 245                 if (ZSTD_equivalentParams(params, zc->params)) {
 246                         zc->flagStaticTables = 0;
 247                         zc->flagStaticHufTable = HUF_repeat_none;
 248                         return ZSTD_continueCCtx(zc, params, frameContentSize);
 249                 }
 250 
 251         {
 252                 size_t const blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, (size_t)1 << params.cParams.windowLog);
 253                 U32 const divider = (params.cParams.searchLength == 3) ? 3 : 4;
 254                 size_t const maxNbSeq = blockSize / divider;
 255                 size_t const tokenSpace = blockSize + 11 * maxNbSeq;
 256                 size_t const chainSize = (params.cParams.strategy == ZSTD_fast) ? 0 : (1 << params.cParams.chainLog);
 257                 size_t const hSize = ((size_t)1) << params.cParams.hashLog;
 258                 U32 const hashLog3 = (params.cParams.searchLength > 3) ? 0 : MIN(ZSTD_HASHLOG3_MAX, params.cParams.windowLog);
 259                 size_t const h3Size = ((size_t)1) << hashLog3;
 260                 size_t const tableSpace = (chainSize + hSize + h3Size) * sizeof(U32);
 261                 void *ptr;
 262 
 263                 /* Check if workSpace is large enough, alloc a new one if needed */
 264                 {
 265                         size_t const optSpace = ((MaxML + 1) + (MaxLL + 1) + (MaxOff + 1) + (1 << Litbits)) * sizeof(U32) +
 266                                                 (ZSTD_OPT_NUM + 1) * (sizeof(ZSTD_match_t) + sizeof(ZSTD_optimal_t));
 267                         size_t const neededSpace = tableSpace + (256 * sizeof(U32)) /* huffTable */ + tokenSpace +
 268                                                    (((params.cParams.strategy == ZSTD_btopt) || (params.cParams.strategy == ZSTD_btopt2)) ? optSpace : 0);
 269                         if (zc->workSpaceSize < neededSpace) {
 270                                 ZSTD_free(zc->workSpace, zc->customMem);
 271                                 zc->workSpace = ZSTD_malloc(neededSpace, zc->customMem);
 272                                 if (zc->workSpace == NULL)
 273                                         return ERROR(memory_allocation);
 274                                 zc->workSpaceSize = neededSpace;
 275                         }
 276                 }
 277 
 278                 if (crp != ZSTDcrp_noMemset)
 279                         memset(zc->workSpace, 0, tableSpace); /* reset tables only */
 280                 xxh64_reset(&zc->xxhState, 0);
 281                 zc->hashLog3 = hashLog3;
 282                 zc->hashTable = (U32 *)(zc->workSpace);
 283                 zc->chainTable = zc->hashTable + hSize;
 284                 zc->hashTable3 = zc->chainTable + chainSize;
 285                 ptr = zc->hashTable3 + h3Size;
 286                 zc->hufTable = (HUF_CElt *)ptr;
 287                 zc->flagStaticTables = 0;
 288                 zc->flagStaticHufTable = HUF_repeat_none;
 289                 ptr = ((U32 *)ptr) + 256; /* note : HUF_CElt* is incomplete type, size is simulated using U32 */
 290 
 291                 zc->nextToUpdate = 1;
 292                 zc->nextSrc = NULL;
 293                 zc->base = NULL;
 294                 zc->dictBase = NULL;
 295                 zc->dictLimit = 0;
 296                 zc->lowLimit = 0;
 297                 zc->params = params;
 298                 zc->blockSize = blockSize;
 299                 zc->frameContentSize = frameContentSize;
 300                 {
 301                         int i;
 302                         for (i = 0; i < ZSTD_REP_NUM; i++)
 303                                 zc->rep[i] = repStartValue[i];
 304                 }
 305 
 306                 if ((params.cParams.strategy == ZSTD_btopt) || (params.cParams.strategy == ZSTD_btopt2)) {
 307                         zc->seqStore.litFreq = (U32 *)ptr;
 308                         zc->seqStore.litLengthFreq = zc->seqStore.litFreq + (1 << Litbits);
 309                         zc->seqStore.matchLengthFreq = zc->seqStore.litLengthFreq + (MaxLL + 1);
 310                         zc->seqStore.offCodeFreq = zc->seqStore.matchLengthFreq + (MaxML + 1);
 311                         ptr = zc->seqStore.offCodeFreq + (MaxOff + 1);
 312                         zc->seqStore.matchTable = (ZSTD_match_t *)ptr;
 313                         ptr = zc->seqStore.matchTable + ZSTD_OPT_NUM + 1;
 314                         zc->seqStore.priceTable = (ZSTD_optimal_t *)ptr;
 315                         ptr = zc->seqStore.priceTable + ZSTD_OPT_NUM + 1;
 316                         zc->seqStore.litLengthSum = 0;
 317                 }
 318                 zc->seqStore.sequencesStart = (seqDef *)ptr;
 319                 ptr = zc->seqStore.sequencesStart + maxNbSeq;
 320                 zc->seqStore.llCode = (BYTE *)ptr;
 321                 zc->seqStore.mlCode = zc->seqStore.llCode + maxNbSeq;
 322                 zc->seqStore.ofCode = zc->seqStore.mlCode + maxNbSeq;
 323                 zc->seqStore.litStart = zc->seqStore.ofCode + maxNbSeq;
 324 
 325                 zc->stage = ZSTDcs_init;
 326                 zc->dictID = 0;
 327                 zc->loadedDictEnd = 0;
 328 
 329                 return 0;
 330         }
 331 }
 332 
 333 /* ZSTD_invalidateRepCodes() :
 334  * ensures next compression will not use repcodes from previous block.
 335  * Note : only works with regular variant;
 336  *        do not use with extDict variant ! */
 337 void ZSTD_invalidateRepCodes(ZSTD_CCtx *cctx)
 338 {
 339         int i;
 340         for (i = 0; i < ZSTD_REP_NUM; i++)
 341                 cctx->rep[i] = 0;
 342 }
 343 
 344 /*! ZSTD_copyCCtx() :
 345 *   Duplicate an existing context `srcCCtx` into another one `dstCCtx`.
 346 *   Only works during stage ZSTDcs_init (i.e. after creation, but before first call to ZSTD_compressContinue()).
 347 *   @return : 0, or an error code */
 348 size_t ZSTD_copyCCtx(ZSTD_CCtx *dstCCtx, const ZSTD_CCtx *srcCCtx, unsigned long long pledgedSrcSize)
 349 {
 350         if (srcCCtx->stage != ZSTDcs_init)
 351                 return ERROR(stage_wrong);
 352 
 353         memcpy(&dstCCtx->customMem, &srcCCtx->customMem, sizeof(ZSTD_customMem));
 354         {
 355                 ZSTD_parameters params = srcCCtx->params;
 356                 params.fParams.contentSizeFlag = (pledgedSrcSize > 0);
 357                 ZSTD_resetCCtx_advanced(dstCCtx, params, pledgedSrcSize, ZSTDcrp_noMemset);
 358         }
 359 
 360         /* copy tables */
 361         {
 362                 size_t const chainSize = (srcCCtx->params.cParams.strategy == ZSTD_fast) ? 0 : (1 << srcCCtx->params.cParams.chainLog);
 363                 size_t const hSize = ((size_t)1) << srcCCtx->params.cParams.hashLog;
 364                 size_t const h3Size = (size_t)1 << srcCCtx->hashLog3;
 365                 size_t const tableSpace = (chainSize + hSize + h3Size) * sizeof(U32);
 366                 memcpy(dstCCtx->workSpace, srcCCtx->workSpace, tableSpace);
 367         }
 368 
 369         /* copy dictionary offsets */
 370         dstCCtx->nextToUpdate = srcCCtx->nextToUpdate;
 371         dstCCtx->nextToUpdate3 = srcCCtx->nextToUpdate3;
 372         dstCCtx->nextSrc = srcCCtx->nextSrc;
 373         dstCCtx->base = srcCCtx->base;
 374         dstCCtx->dictBase = srcCCtx->dictBase;
 375         dstCCtx->dictLimit = srcCCtx->dictLimit;
 376         dstCCtx->lowLimit = srcCCtx->lowLimit;
 377         dstCCtx->loadedDictEnd = srcCCtx->loadedDictEnd;
 378         dstCCtx->dictID = srcCCtx->dictID;
 379 
 380         /* copy entropy tables */
 381         dstCCtx->flagStaticTables = srcCCtx->flagStaticTables;
 382         dstCCtx->flagStaticHufTable = srcCCtx->flagStaticHufTable;
 383         if (srcCCtx->flagStaticTables) {
 384                 memcpy(dstCCtx->litlengthCTable, srcCCtx->litlengthCTable, sizeof(dstCCtx->litlengthCTable));
 385                 memcpy(dstCCtx->matchlengthCTable, srcCCtx->matchlengthCTable, sizeof(dstCCtx->matchlengthCTable));
 386                 memcpy(dstCCtx->offcodeCTable, srcCCtx->offcodeCTable, sizeof(dstCCtx->offcodeCTable));
 387         }
 388         if (srcCCtx->flagStaticHufTable) {
 389                 memcpy(dstCCtx->hufTable, srcCCtx->hufTable, 256 * 4);
 390         }
 391 
 392         return 0;
 393 }
 394 
 395 /*! ZSTD_reduceTable() :
 396 *   reduce table indexes by `reducerValue` */
 397 static void ZSTD_reduceTable(U32 *const table, U32 const size, U32 const reducerValue)
 398 {
 399         U32 u;
 400         for (u = 0; u < size; u++) {
 401                 if (table[u] < reducerValue)
 402                         table[u] = 0;
 403                 else
 404                         table[u] -= reducerValue;
 405         }
 406 }
 407 
 408 /*! ZSTD_reduceIndex() :
 409 *   rescale all indexes to avoid future overflow (indexes are U32) */
 410 static void ZSTD_reduceIndex(ZSTD_CCtx *zc, const U32 reducerValue)
 411 {
 412         {
 413                 U32 const hSize = 1 << zc->params.cParams.hashLog;
 414                 ZSTD_reduceTable(zc->hashTable, hSize, reducerValue);
 415         }
 416 
 417         {
 418                 U32 const chainSize = (zc->params.cParams.strategy == ZSTD_fast) ? 0 : (1 << zc->params.cParams.chainLog);
 419                 ZSTD_reduceTable(zc->chainTable, chainSize, reducerValue);
 420         }
 421 
 422         {
 423                 U32 const h3Size = (zc->hashLog3) ? 1 << zc->hashLog3 : 0;
 424                 ZSTD_reduceTable(zc->hashTable3, h3Size, reducerValue);
 425         }
 426 }
 427 
 428 /*-*******************************************************
 429 *  Block entropic compression
 430 *********************************************************/
 431 
 432 /* See doc/zstd_compression_format.md for detailed format description */
 433 
 434 size_t ZSTD_noCompressBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
 435 {
 436         if (srcSize + ZSTD_blockHeaderSize > dstCapacity)
 437                 return ERROR(dstSize_tooSmall);
 438         memcpy((BYTE *)dst + ZSTD_blockHeaderSize, src, srcSize);
 439         ZSTD_writeLE24(dst, (U32)(srcSize << 2) + (U32)bt_raw);
 440         return ZSTD_blockHeaderSize + srcSize;
 441 }
 442 
 443 static size_t ZSTD_noCompressLiterals(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
 444 {
 445         BYTE *const ostart = (BYTE * const)dst;
 446         U32 const flSize = 1 + (srcSize > 31) + (srcSize > 4095);
 447 
 448         if (srcSize + flSize > dstCapacity)
 449                 return ERROR(dstSize_tooSmall);
 450 
 451         switch (flSize) {
 452         case 1: /* 2 - 1 - 5 */ ostart[0] = (BYTE)((U32)set_basic + (srcSize << 3)); break;
 453         case 2: /* 2 - 2 - 12 */ ZSTD_writeLE16(ostart, (U16)((U32)set_basic + (1 << 2) + (srcSize << 4))); break;
 454         default: /*note : should not be necessary : flSize is within {1,2,3} */
 455         case 3: /* 2 - 2 - 20 */ ZSTD_writeLE32(ostart, (U32)((U32)set_basic + (3 << 2) + (srcSize << 4))); break;
 456         }
 457 
 458         memcpy(ostart + flSize, src, srcSize);
 459         return srcSize + flSize;
 460 }
 461 
 462 static size_t ZSTD_compressRleLiteralsBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
 463 {
 464         BYTE *const ostart = (BYTE * const)dst;
 465         U32 const flSize = 1 + (srcSize > 31) + (srcSize > 4095);
 466 
 467         (void)dstCapacity; /* dstCapacity already guaranteed to be >=4, hence large enough */
 468 
 469         switch (flSize) {
 470         case 1: /* 2 - 1 - 5 */ ostart[0] = (BYTE)((U32)set_rle + (srcSize << 3)); break;
 471         case 2: /* 2 - 2 - 12 */ ZSTD_writeLE16(ostart, (U16)((U32)set_rle + (1 << 2) + (srcSize << 4))); break;
 472         default: /*note : should not be necessary : flSize is necessarily within {1,2,3} */
 473         case 3: /* 2 - 2 - 20 */ ZSTD_writeLE32(ostart, (U32)((U32)set_rle + (3 << 2) + (srcSize << 4))); break;
 474         }
 475 
 476         ostart[flSize] = *(const BYTE *)src;
 477         return flSize + 1;
 478 }
 479 
 480 static size_t ZSTD_minGain(size_t srcSize) { return (srcSize >> 6) + 2; }
 481 
 482 static size_t ZSTD_compressLiterals(ZSTD_CCtx *zc, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
 483 {
 484         size_t const minGain = ZSTD_minGain(srcSize);
 485         size_t const lhSize = 3 + (srcSize >= 1 KB) + (srcSize >= 16 KB);
 486         BYTE *const ostart = (BYTE *)dst;
 487         U32 singleStream = srcSize < 256;
 488         symbolEncodingType_e hType = set_compressed;
 489         size_t cLitSize;
 490 
 491 /* small ? don't even attempt compression (speed opt) */
 492 #define LITERAL_NOENTROPY 63
 493         {
 494                 size_t const minLitSize = zc->flagStaticHufTable == HUF_repeat_valid ? 6 : LITERAL_NOENTROPY;
 495                 if (srcSize <= minLitSize)
 496                         return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
 497         }
 498 
 499         if (dstCapacity < lhSize + 1)
 500                 return ERROR(dstSize_tooSmall); /* not enough space for compression */
 501         {
 502                 HUF_repeat repeat = zc->flagStaticHufTable;
 503                 int const preferRepeat = zc->params.cParams.strategy < ZSTD_lazy ? srcSize <= 1024 : 0;
 504                 if (repeat == HUF_repeat_valid && lhSize == 3)
 505                         singleStream = 1;
 506                 cLitSize = singleStream ? HUF_compress1X_repeat(ostart + lhSize, dstCapacity - lhSize, src, srcSize, 255, 11, zc->tmpCounters,
 507                                                                 sizeof(zc->tmpCounters), zc->hufTable, &repeat, preferRepeat)
 508                                         : HUF_compress4X_repeat(ostart + lhSize, dstCapacity - lhSize, src, srcSize, 255, 11, zc->tmpCounters,
 509                                                                 sizeof(zc->tmpCounters), zc->hufTable, &repeat, preferRepeat);
 510                 if (repeat != HUF_repeat_none) {
 511                         hType = set_repeat;
 512                 } /* reused the existing table */
 513                 else {
 514                         zc->flagStaticHufTable = HUF_repeat_check;
 515                 } /* now have a table to reuse */
 516         }
 517 
 518         if ((cLitSize == 0) | (cLitSize >= srcSize - minGain)) {
 519                 zc->flagStaticHufTable = HUF_repeat_none;
 520                 return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
 521         }
 522         if (cLitSize == 1) {
 523                 zc->flagStaticHufTable = HUF_repeat_none;
 524                 return ZSTD_compressRleLiteralsBlock(dst, dstCapacity, src, srcSize);
 525         }
 526 
 527         /* Build header */
 528         switch (lhSize) {
 529         case 3: /* 2 - 2 - 10 - 10 */
 530         {
 531                 U32 const lhc = hType + ((!singleStream) << 2) + ((U32)srcSize << 4) + ((U32)cLitSize << 14);
 532                 ZSTD_writeLE24(ostart, lhc);
 533                 break;
 534         }
 535         case 4: /* 2 - 2 - 14 - 14 */
 536         {
 537                 U32 const lhc = hType + (2 << 2) + ((U32)srcSize << 4) + ((U32)cLitSize << 18);
 538                 ZSTD_writeLE32(ostart, lhc);
 539                 break;
 540         }
 541         default: /* should not be necessary, lhSize is only {3,4,5} */
 542         case 5:  /* 2 - 2 - 18 - 18 */
 543         {
 544                 U32 const lhc = hType + (3 << 2) + ((U32)srcSize << 4) + ((U32)cLitSize << 22);
 545                 ZSTD_writeLE32(ostart, lhc);
 546                 ostart[4] = (BYTE)(cLitSize >> 10);
 547                 break;
 548         }
 549         }
 550         return lhSize + cLitSize;
 551 }
 552 
 553 static const BYTE LL_Code[64] = {0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10, 11, 12, 13, 14, 15, 16, 16, 17, 17, 18, 18,
 554                                  19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23,
 555                                  23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24};
 556 
 557 static const BYTE ML_Code[128] = {0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
 558                                   26, 27, 28, 29, 30, 31, 32, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 37, 37, 37, 37, 38, 38, 38, 38,
 559                                   38, 38, 38, 38, 39, 39, 39, 39, 39, 39, 39, 39, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,
 560                                   40, 40, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 42, 42, 42, 42, 42, 42, 42, 42,
 561                                   42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42};
 562 
 563 void ZSTD_seqToCodes(const seqStore_t *seqStorePtr)
 564 {
 565         BYTE const LL_deltaCode = 19;
 566         BYTE const ML_deltaCode = 36;
 567         const seqDef *const sequences = seqStorePtr->sequencesStart;
 568         BYTE *const llCodeTable = seqStorePtr->llCode;
 569         BYTE *const ofCodeTable = seqStorePtr->ofCode;
 570         BYTE *const mlCodeTable = seqStorePtr->mlCode;
 571         U32 const nbSeq = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
 572         U32 u;
 573         for (u = 0; u < nbSeq; u++) {
 574                 U32 const llv = sequences[u].litLength;
 575                 U32 const mlv = sequences[u].matchLength;
 576                 llCodeTable[u] = (llv > 63) ? (BYTE)ZSTD_highbit32(llv) + LL_deltaCode : LL_Code[llv];
 577                 ofCodeTable[u] = (BYTE)ZSTD_highbit32(sequences[u].offset);
 578                 mlCodeTable[u] = (mlv > 127) ? (BYTE)ZSTD_highbit32(mlv) + ML_deltaCode : ML_Code[mlv];
 579         }
 580         if (seqStorePtr->longLengthID == 1)
 581                 llCodeTable[seqStorePtr->longLengthPos] = MaxLL;
 582         if (seqStorePtr->longLengthID == 2)
 583                 mlCodeTable[seqStorePtr->longLengthPos] = MaxML;
 584 }
 585 
 586 ZSTD_STATIC size_t ZSTD_compressSequences_internal(ZSTD_CCtx *zc, void *dst, size_t dstCapacity)
 587 {
 588         const int longOffsets = zc->params.cParams.windowLog > STREAM_ACCUMULATOR_MIN;
 589         const seqStore_t *seqStorePtr = &(zc->seqStore);
 590         FSE_CTable *CTable_LitLength = zc->litlengthCTable;
 591         FSE_CTable *CTable_OffsetBits = zc->offcodeCTable;
 592         FSE_CTable *CTable_MatchLength = zc->matchlengthCTable;
 593         U32 LLtype, Offtype, MLtype; /* compressed, raw or rle */
 594         const seqDef *const sequences = seqStorePtr->sequencesStart;
 595         const BYTE *const ofCodeTable = seqStorePtr->ofCode;
 596         const BYTE *const llCodeTable = seqStorePtr->llCode;
 597         const BYTE *const mlCodeTable = seqStorePtr->mlCode;
 598         BYTE *const ostart = (BYTE *)dst;
 599         BYTE *const oend = ostart + dstCapacity;
 600         BYTE *op = ostart;
 601         size_t const nbSeq = seqStorePtr->sequences - seqStorePtr->sequencesStart;
 602         BYTE *seqHead;
 603 
 604         U32 *count;
 605         S16 *norm;
 606         U32 *workspace;
 607         size_t workspaceSize = sizeof(zc->tmpCounters);
 608         {
 609                 size_t spaceUsed32 = 0;
 610                 count = (U32 *)zc->tmpCounters + spaceUsed32;
 611                 spaceUsed32 += MaxSeq + 1;
 612                 norm = (S16 *)((U32 *)zc->tmpCounters + spaceUsed32);
 613                 spaceUsed32 += ALIGN(sizeof(S16) * (MaxSeq + 1), sizeof(U32)) >> 2;
 614 
 615                 workspace = (U32 *)zc->tmpCounters + spaceUsed32;
 616                 workspaceSize -= (spaceUsed32 << 2);
 617         }
 618 
 619         /* Compress literals */
 620         {
 621                 const BYTE *const literals = seqStorePtr->litStart;
 622                 size_t const litSize = seqStorePtr->lit - literals;
 623                 size_t const cSize = ZSTD_compressLiterals(zc, op, dstCapacity, literals, litSize);
 624                 if (ZSTD_isError(cSize))
 625                         return cSize;
 626                 op += cSize;
 627         }
 628 
 629         /* Sequences Header */
 630         if ((oend - op) < 3 /*max nbSeq Size*/ + 1 /*seqHead */)
 631                 return ERROR(dstSize_tooSmall);
 632         if (nbSeq < 0x7F)
 633                 *op++ = (BYTE)nbSeq;
 634         else if (nbSeq < LONGNBSEQ)
 635                 op[0] = (BYTE)((nbSeq >> 8) + 0x80), op[1] = (BYTE)nbSeq, op += 2;
 636         else
 637                 op[0] = 0xFF, ZSTD_writeLE16(op + 1, (U16)(nbSeq - LONGNBSEQ)), op += 3;
 638         if (nbSeq == 0)
 639                 return op - ostart;
 640 
 641         /* seqHead : flags for FSE encoding type */
 642         seqHead = op++;
 643 
 644 #define MIN_SEQ_FOR_DYNAMIC_FSE 64
 645 #define MAX_SEQ_FOR_STATIC_FSE 1000
 646 
 647         /* convert length/distances into codes */
 648         ZSTD_seqToCodes(seqStorePtr);
 649 
 650         /* CTable for Literal Lengths */
 651         {
 652                 U32 max = MaxLL;
 653                 size_t const mostFrequent = FSE_countFast_wksp(count, &max, llCodeTable, nbSeq, workspace);
 654                 if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
 655                         *op++ = llCodeTable[0];
 656                         FSE_buildCTable_rle(CTable_LitLength, (BYTE)max);
 657                         LLtype = set_rle;
 658                 } else if ((zc->flagStaticTables) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
 659                         LLtype = set_repeat;
 660                 } else if ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (LL_defaultNormLog - 1)))) {
 661                         FSE_buildCTable_wksp(CTable_LitLength, LL_defaultNorm, MaxLL, LL_defaultNormLog, workspace, workspaceSize);
 662                         LLtype = set_basic;
 663                 } else {
 664                         size_t nbSeq_1 = nbSeq;
 665                         const U32 tableLog = FSE_optimalTableLog(LLFSELog, nbSeq, max);
 666                         if (count[llCodeTable[nbSeq - 1]] > 1) {
 667                                 count[llCodeTable[nbSeq - 1]]--;
 668                                 nbSeq_1--;
 669                         }
 670                         FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max);
 671                         {
 672                                 size_t const NCountSize = FSE_writeNCount(op, oend - op, norm, max, tableLog); /* overflow protected */
 673                                 if (FSE_isError(NCountSize))
 674                                         return NCountSize;
 675                                 op += NCountSize;
 676                         }
 677                         FSE_buildCTable_wksp(CTable_LitLength, norm, max, tableLog, workspace, workspaceSize);
 678                         LLtype = set_compressed;
 679                 }
 680         }
 681 
 682         /* CTable for Offsets */
 683         {
 684                 U32 max = MaxOff;
 685                 size_t const mostFrequent = FSE_countFast_wksp(count, &max, ofCodeTable, nbSeq, workspace);
 686                 if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
 687                         *op++ = ofCodeTable[0];
 688                         FSE_buildCTable_rle(CTable_OffsetBits, (BYTE)max);
 689                         Offtype = set_rle;
 690                 } else if ((zc->flagStaticTables) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
 691                         Offtype = set_repeat;
 692                 } else if ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (OF_defaultNormLog - 1)))) {
 693                         FSE_buildCTable_wksp(CTable_OffsetBits, OF_defaultNorm, MaxOff, OF_defaultNormLog, workspace, workspaceSize);
 694                         Offtype = set_basic;
 695                 } else {
 696                         size_t nbSeq_1 = nbSeq;
 697                         const U32 tableLog = FSE_optimalTableLog(OffFSELog, nbSeq, max);
 698                         if (count[ofCodeTable[nbSeq - 1]] > 1) {
 699                                 count[ofCodeTable[nbSeq - 1]]--;
 700                                 nbSeq_1--;
 701                         }
 702                         FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max);
 703                         {
 704                                 size_t const NCountSize = FSE_writeNCount(op, oend - op, norm, max, tableLog); /* overflow protected */
 705                                 if (FSE_isError(NCountSize))
 706                                         return NCountSize;
 707                                 op += NCountSize;
 708                         }
 709                         FSE_buildCTable_wksp(CTable_OffsetBits, norm, max, tableLog, workspace, workspaceSize);
 710                         Offtype = set_compressed;
 711                 }
 712         }
 713 
 714         /* CTable for MatchLengths */
 715         {
 716                 U32 max = MaxML;
 717                 size_t const mostFrequent = FSE_countFast_wksp(count, &max, mlCodeTable, nbSeq, workspace);
 718                 if ((mostFrequent == nbSeq) && (nbSeq > 2)) {
 719                         *op++ = *mlCodeTable;
 720                         FSE_buildCTable_rle(CTable_MatchLength, (BYTE)max);
 721                         MLtype = set_rle;
 722                 } else if ((zc->flagStaticTables) && (nbSeq < MAX_SEQ_FOR_STATIC_FSE)) {
 723                         MLtype = set_repeat;
 724                 } else if ((nbSeq < MIN_SEQ_FOR_DYNAMIC_FSE) || (mostFrequent < (nbSeq >> (ML_defaultNormLog - 1)))) {
 725                         FSE_buildCTable_wksp(CTable_MatchLength, ML_defaultNorm, MaxML, ML_defaultNormLog, workspace, workspaceSize);
 726                         MLtype = set_basic;
 727                 } else {
 728                         size_t nbSeq_1 = nbSeq;
 729                         const U32 tableLog = FSE_optimalTableLog(MLFSELog, nbSeq, max);
 730                         if (count[mlCodeTable[nbSeq - 1]] > 1) {
 731                                 count[mlCodeTable[nbSeq - 1]]--;
 732                                 nbSeq_1--;
 733                         }
 734                         FSE_normalizeCount(norm, tableLog, count, nbSeq_1, max);
 735                         {
 736                                 size_t const NCountSize = FSE_writeNCount(op, oend - op, norm, max, tableLog); /* overflow protected */
 737                                 if (FSE_isError(NCountSize))
 738                                         return NCountSize;
 739                                 op += NCountSize;
 740                         }
 741                         FSE_buildCTable_wksp(CTable_MatchLength, norm, max, tableLog, workspace, workspaceSize);
 742                         MLtype = set_compressed;
 743                 }
 744         }
 745 
 746         *seqHead = (BYTE)((LLtype << 6) + (Offtype << 4) + (MLtype << 2));
 747         zc->flagStaticTables = 0;
 748 
 749         /* Encoding Sequences */
 750         {
 751                 BIT_CStream_t blockStream;
 752                 FSE_CState_t stateMatchLength;
 753                 FSE_CState_t stateOffsetBits;
 754                 FSE_CState_t stateLitLength;
 755 
 756                 CHECK_E(BIT_initCStream(&blockStream, op, oend - op), dstSize_tooSmall); /* not enough space remaining */
 757 
 758                 /* first symbols */
 759                 FSE_initCState2(&stateMatchLength, CTable_MatchLength, mlCodeTable[nbSeq - 1]);
 760                 FSE_initCState2(&stateOffsetBits, CTable_OffsetBits, ofCodeTable[nbSeq - 1]);
 761                 FSE_initCState2(&stateLitLength, CTable_LitLength, llCodeTable[nbSeq - 1]);
 762                 BIT_addBits(&blockStream, sequences[nbSeq - 1].litLength, LL_bits[llCodeTable[nbSeq - 1]]);
 763                 if (ZSTD_32bits())
 764                         BIT_flushBits(&blockStream);
 765                 BIT_addBits(&blockStream, sequences[nbSeq - 1].matchLength, ML_bits[mlCodeTable[nbSeq - 1]]);
 766                 if (ZSTD_32bits())
 767                         BIT_flushBits(&blockStream);
 768                 if (longOffsets) {
 769                         U32 const ofBits = ofCodeTable[nbSeq - 1];
 770                         int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN - 1);
 771                         if (extraBits) {
 772                                 BIT_addBits(&blockStream, sequences[nbSeq - 1].offset, extraBits);
 773                                 BIT_flushBits(&blockStream);
 774                         }
 775                         BIT_addBits(&blockStream, sequences[nbSeq - 1].offset >> extraBits, ofBits - extraBits);
 776                 } else {
 777                         BIT_addBits(&blockStream, sequences[nbSeq - 1].offset, ofCodeTable[nbSeq - 1]);
 778                 }
 779                 BIT_flushBits(&blockStream);
 780 
 781                 {
 782                         size_t n;
 783                         for (n = nbSeq - 2; n < nbSeq; n--) { /* intentional underflow */
 784                                 BYTE const llCode = llCodeTable[n];
 785                                 BYTE const ofCode = ofCodeTable[n];
 786                                 BYTE const mlCode = mlCodeTable[n];
 787                                 U32 const llBits = LL_bits[llCode];
 788                                 U32 const ofBits = ofCode; /* 32b*/ /* 64b*/
 789                                 U32 const mlBits = ML_bits[mlCode];
 790                                 /* (7)*/                                                            /* (7)*/
 791                                 FSE_encodeSymbol(&blockStream, &stateOffsetBits, ofCode); /* 15 */  /* 15 */
 792                                 FSE_encodeSymbol(&blockStream, &stateMatchLength, mlCode); /* 24 */ /* 24 */
 793                                 if (ZSTD_32bits())
 794                                         BIT_flushBits(&blockStream);                              /* (7)*/
 795                                 FSE_encodeSymbol(&blockStream, &stateLitLength, llCode); /* 16 */ /* 33 */
 796                                 if (ZSTD_32bits() || (ofBits + mlBits + llBits >= 64 - 7 - (LLFSELog + MLFSELog + OffFSELog)))
 797                                         BIT_flushBits(&blockStream); /* (7)*/
 798                                 BIT_addBits(&blockStream, sequences[n].litLength, llBits);
 799                                 if (ZSTD_32bits() && ((llBits + mlBits) > 24))
 800                                         BIT_flushBits(&blockStream);
 801                                 BIT_addBits(&blockStream, sequences[n].matchLength, mlBits);
 802                                 if (ZSTD_32bits())
 803                                         BIT_flushBits(&blockStream); /* (7)*/
 804                                 if (longOffsets) {
 805                                         int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN - 1);
 806                                         if (extraBits) {
 807                                                 BIT_addBits(&blockStream, sequences[n].offset, extraBits);
 808                                                 BIT_flushBits(&blockStream); /* (7)*/
 809                                         }
 810                                         BIT_addBits(&blockStream, sequences[n].offset >> extraBits, ofBits - extraBits); /* 31 */
 811                                 } else {
 812                                         BIT_addBits(&blockStream, sequences[n].offset, ofBits); /* 31 */
 813                                 }
 814                                 BIT_flushBits(&blockStream); /* (7)*/
 815                         }
 816                 }
 817 
 818                 FSE_flushCState(&blockStream, &stateMatchLength);
 819                 FSE_flushCState(&blockStream, &stateOffsetBits);
 820                 FSE_flushCState(&blockStream, &stateLitLength);
 821 
 822                 {
 823                         size_t const streamSize = BIT_closeCStream(&blockStream);
 824                         if (streamSize == 0)
 825                                 return ERROR(dstSize_tooSmall); /* not enough space */
 826                         op += streamSize;
 827                 }
 828         }
 829         return op - ostart;
 830 }
 831 
 832 ZSTD_STATIC size_t ZSTD_compressSequences(ZSTD_CCtx *zc, void *dst, size_t dstCapacity, size_t srcSize)
 833 {
 834         size_t const cSize = ZSTD_compressSequences_internal(zc, dst, dstCapacity);
 835         size_t const minGain = ZSTD_minGain(srcSize);
 836         size_t const maxCSize = srcSize - minGain;
 837         /* If the srcSize <= dstCapacity, then there is enough space to write a
 838          * raw uncompressed block. Since we ran out of space, the block must not
 839          * be compressible, so fall back to a raw uncompressed block.
 840          */
 841         int const uncompressibleError = cSize == ERROR(dstSize_tooSmall) && srcSize <= dstCapacity;
 842         int i;
 843 
 844         if (ZSTD_isError(cSize) && !uncompressibleError)
 845                 return cSize;
 846         if (cSize >= maxCSize || uncompressibleError) {
 847                 zc->flagStaticHufTable = HUF_repeat_none;
 848                 return 0;
 849         }
 850         /* confirm repcodes */
 851         for (i = 0; i < ZSTD_REP_NUM; i++)
 852                 zc->rep[i] = zc->repToConfirm[i];
 853         return cSize;
 854 }
 855 
 856 /*! ZSTD_storeSeq() :
 857         Store a sequence (literal length, literals, offset code and match length code) into seqStore_t.
 858         `offsetCode` : distance to match, or 0 == repCode.
 859         `matchCode` : matchLength - MINMATCH
 860 */
 861 ZSTD_STATIC void ZSTD_storeSeq(seqStore_t *seqStorePtr, size_t litLength, const void *literals, U32 offsetCode, size_t matchCode)
 862 {
 863         /* copy Literals */
 864         ZSTD_wildcopy(seqStorePtr->lit, literals, litLength);
 865         seqStorePtr->lit += litLength;
 866 
 867         /* literal Length */
 868         if (litLength > 0xFFFF) {
 869                 seqStorePtr->longLengthID = 1;
 870                 seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
 871         }
 872         seqStorePtr->sequences[0].litLength = (U16)litLength;
 873 
 874         /* match offset */
 875         seqStorePtr->sequences[0].offset = offsetCode + 1;
 876 
 877         /* match Length */
 878         if (matchCode > 0xFFFF) {
 879                 seqStorePtr->longLengthID = 2;
 880                 seqStorePtr->longLengthPos = (U32)(seqStorePtr->sequences - seqStorePtr->sequencesStart);
 881         }
 882         seqStorePtr->sequences[0].matchLength = (U16)matchCode;
 883 
 884         seqStorePtr->sequences++;
 885 }
 886 
 887 /*-*************************************
 888 *  Match length counter
 889 ***************************************/
 890 static unsigned ZSTD_NbCommonBytes(register size_t val)
 891 {
 892         if (ZSTD_isLittleEndian()) {
 893                 if (ZSTD_64bits()) {
 894                         return (__builtin_ctzll((U64)val) >> 3);
 895                 } else { /* 32 bits */
 896                         return (__builtin_ctz((U32)val) >> 3);
 897                 }
 898         } else { /* Big Endian CPU */
 899                 if (ZSTD_64bits()) {
 900                         return (__builtin_clzll(val) >> 3);
 901                 } else { /* 32 bits */
 902                         return (__builtin_clz((U32)val) >> 3);
 903                 }
 904         }
 905 }
 906 
 907 static size_t ZSTD_count(const BYTE *pIn, const BYTE *pMatch, const BYTE *const pInLimit)
 908 {
 909         const BYTE *const pStart = pIn;
 910         const BYTE *const pInLoopLimit = pInLimit - (sizeof(size_t) - 1);
 911 
 912         while (pIn < pInLoopLimit) {
 913                 size_t const diff = ZSTD_readST(pMatch) ^ ZSTD_readST(pIn);
 914                 if (!diff) {
 915                         pIn += sizeof(size_t);
 916                         pMatch += sizeof(size_t);
 917                         continue;
 918                 }
 919                 pIn += ZSTD_NbCommonBytes(diff);
 920                 return (size_t)(pIn - pStart);
 921         }
 922         if (ZSTD_64bits())
 923                 if ((pIn < (pInLimit - 3)) && (ZSTD_read32(pMatch) == ZSTD_read32(pIn))) {
 924                         pIn += 4;
 925                         pMatch += 4;
 926                 }
 927         if ((pIn < (pInLimit - 1)) && (ZSTD_read16(pMatch) == ZSTD_read16(pIn))) {
 928                 pIn += 2;
 929                 pMatch += 2;
 930         }
 931         if ((pIn < pInLimit) && (*pMatch == *pIn))
 932                 pIn++;
 933         return (size_t)(pIn - pStart);
 934 }
 935 
 936 /** ZSTD_count_2segments() :
 937 *   can count match length with `ip` & `match` in 2 different segments.
 938 *   convention : on reaching mEnd, match count continue starting from iStart
 939 */
 940 static size_t ZSTD_count_2segments(const BYTE *ip, const BYTE *match, const BYTE *iEnd, const BYTE *mEnd, const BYTE *iStart)
 941 {
 942         const BYTE *const vEnd = MIN(ip + (mEnd - match), iEnd);
 943         size_t const matchLength = ZSTD_count(ip, match, vEnd);
 944         if (match + matchLength != mEnd)
 945                 return matchLength;
 946         return matchLength + ZSTD_count(ip + matchLength, iStart, iEnd);
 947 }
 948 
 949 /*-*************************************
 950 *  Hashes
 951 ***************************************/
 952 static const U32 prime3bytes = 506832829U;
 953 static U32 ZSTD_hash3(U32 u, U32 h) { return ((u << (32 - 24)) * prime3bytes) >> (32 - h); }
 954 ZSTD_STATIC size_t ZSTD_hash3Ptr(const void *ptr, U32 h) { return ZSTD_hash3(ZSTD_readLE32(ptr), h); } /* only in zstd_opt.h */
 955 
 956 static const U32 prime4bytes = 2654435761U;
 957 static U32 ZSTD_hash4(U32 u, U32 h) { return (u * prime4bytes) >> (32 - h); }
 958 static size_t ZSTD_hash4Ptr(const void *ptr, U32 h) { return ZSTD_hash4(ZSTD_read32(ptr), h); }
 959 
 960 static const U64 prime5bytes = 889523592379ULL;
 961 static size_t ZSTD_hash5(U64 u, U32 h) { return (size_t)(((u << (64 - 40)) * prime5bytes) >> (64 - h)); }
 962 static size_t ZSTD_hash5Ptr(const void *p, U32 h) { return ZSTD_hash5(ZSTD_readLE64(p), h); }
 963 
 964 static const U64 prime6bytes = 227718039650203ULL;
 965 static size_t ZSTD_hash6(U64 u, U32 h) { return (size_t)(((u << (64 - 48)) * prime6bytes) >> (64 - h)); }
 966 static size_t ZSTD_hash6Ptr(const void *p, U32 h) { return ZSTD_hash6(ZSTD_readLE64(p), h); }
 967 
 968 static const U64 prime7bytes = 58295818150454627ULL;
 969 static size_t ZSTD_hash7(U64 u, U32 h) { return (size_t)(((u << (64 - 56)) * prime7bytes) >> (64 - h)); }
 970 static size_t ZSTD_hash7Ptr(const void *p, U32 h) { return ZSTD_hash7(ZSTD_readLE64(p), h); }
 971 
 972 static const U64 prime8bytes = 0xCF1BBCDCB7A56463ULL;
 973 static size_t ZSTD_hash8(U64 u, U32 h) { return (size_t)(((u)*prime8bytes) >> (64 - h)); }
 974 static size_t ZSTD_hash8Ptr(const void *p, U32 h) { return ZSTD_hash8(ZSTD_readLE64(p), h); }
 975 
 976 static size_t ZSTD_hashPtr(const void *p, U32 hBits, U32 mls)
 977 {
 978         switch (mls) {
 979         // case 3: return ZSTD_hash3Ptr(p, hBits);
 980         default:
 981         case 4: return ZSTD_hash4Ptr(p, hBits);
 982         case 5: return ZSTD_hash5Ptr(p, hBits);
 983         case 6: return ZSTD_hash6Ptr(p, hBits);
 984         case 7: return ZSTD_hash7Ptr(p, hBits);
 985         case 8: return ZSTD_hash8Ptr(p, hBits);
 986         }
 987 }
 988 
 989 /*-*************************************
 990 *  Fast Scan
 991 ***************************************/
 992 static void ZSTD_fillHashTable(ZSTD_CCtx *zc, const void *end, const U32 mls)
 993 {
 994         U32 *const hashTable = zc->hashTable;
 995         U32 const hBits = zc->params.cParams.hashLog;
 996         const BYTE *const base = zc->base;
 997         const BYTE *ip = base + zc->nextToUpdate;
 998         const BYTE *const iend = ((const BYTE *)end) - HASH_READ_SIZE;
 999         const size_t fastHashFillStep = 3;
1000 
1001         while (ip <= iend) {
1002                 hashTable[ZSTD_hashPtr(ip, hBits, mls)] = (U32)(ip - base);
1003                 ip += fastHashFillStep;
1004         }
1005 }
1006 
1007 FORCE_INLINE
1008 void ZSTD_compressBlock_fast_generic(ZSTD_CCtx *cctx, const void *src, size_t srcSize, const U32 mls)
1009 {
1010         U32 *const hashTable = cctx->hashTable;
1011         U32 const hBits = cctx->params.cParams.hashLog;
1012         seqStore_t *seqStorePtr = &(cctx->seqStore);
1013         const BYTE *const base = cctx->base;
1014         const BYTE *const istart = (const BYTE *)src;
1015         const BYTE *ip = istart;
1016         const BYTE *anchor = istart;
1017         const U32 lowestIndex = cctx->dictLimit;
1018         const BYTE *const lowest = base + lowestIndex;
1019         const BYTE *const iend = istart + srcSize;
1020         const BYTE *const ilimit = iend - HASH_READ_SIZE;
1021         U32 offset_1 = cctx->rep[0], offset_2 = cctx->rep[1];
1022         U32 offsetSaved = 0;
1023 
1024         /* init */
1025         ip += (ip == lowest);
1026         {
1027                 U32 const maxRep = (U32)(ip - lowest);
1028                 if (offset_2 > maxRep)
1029                         offsetSaved = offset_2, offset_2 = 0;
1030                 if (offset_1 > maxRep)
1031                         offsetSaved = offset_1, offset_1 = 0;
1032         }
1033 
1034         /* Main Search Loop */
1035         while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
1036                 size_t mLength;
1037                 size_t const h = ZSTD_hashPtr(ip, hBits, mls);
1038                 U32 const curr = (U32)(ip - base);
1039                 U32 const matchIndex = hashTable[h];
1040                 const BYTE *match = base + matchIndex;
1041                 hashTable[h] = curr; /* update hash table */
1042 
1043                 if ((offset_1 > 0) & (ZSTD_read32(ip + 1 - offset_1) == ZSTD_read32(ip + 1))) {
1044                         mLength = ZSTD_count(ip + 1 + 4, ip + 1 + 4 - offset_1, iend) + 4;
1045                         ip++;
1046                         ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH);
1047                 } else {
1048                         U32 offset;
1049                         if ((matchIndex <= lowestIndex) || (ZSTD_read32(match) != ZSTD_read32(ip))) {
1050                                 ip += ((ip - anchor) >> g_searchStrength) + 1;
1051                                 continue;
1052                         }
1053                         mLength = ZSTD_count(ip + 4, match + 4, iend) + 4;
1054                         offset = (U32)(ip - match);
1055                         while (((ip > anchor) & (match > lowest)) && (ip[-1] == match[-1])) {
1056                                 ip--;
1057                                 match--;
1058                                 mLength++;
1059                         } /* catch up */
1060                         offset_2 = offset_1;
1061                         offset_1 = offset;
1062 
1063                         ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);
1064                 }
1065 
1066                 /* match found */
1067                 ip += mLength;
1068                 anchor = ip;
1069 
1070                 if (ip <= ilimit) {
1071                         /* Fill Table */
1072                         hashTable[ZSTD_hashPtr(base + curr + 2, hBits, mls)] = curr + 2; /* here because curr+2 could be > iend-8 */
1073                         hashTable[ZSTD_hashPtr(ip - 2, hBits, mls)] = (U32)(ip - 2 - base);
1074                         /* check immediate repcode */
1075                         while ((ip <= ilimit) && ((offset_2 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) {
1076                                 /* store sequence */
1077                                 size_t const rLength = ZSTD_count(ip + 4, ip + 4 - offset_2, iend) + 4;
1078                                 {
1079                                         U32 const tmpOff = offset_2;
1080                                         offset_2 = offset_1;
1081                                         offset_1 = tmpOff;
1082                                 } /* swap offset_2 <=> offset_1 */
1083                                 hashTable[ZSTD_hashPtr(ip, hBits, mls)] = (U32)(ip - base);
1084                                 ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength - MINMATCH);
1085                                 ip += rLength;
1086                                 anchor = ip;
1087                                 continue; /* faster when present ... (?) */
1088                         }
1089                 }
1090         }
1091 
1092         /* save reps for next block */
1093         cctx->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
1094         cctx->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;
1095 
1096         /* Last Literals */
1097         {
1098                 size_t const lastLLSize = iend - anchor;
1099                 memcpy(seqStorePtr->lit, anchor, lastLLSize);
1100                 seqStorePtr->lit += lastLLSize;
1101         }
1102 }
1103 
1104 static void ZSTD_compressBlock_fast(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
1105 {
1106         const U32 mls = ctx->params.cParams.searchLength;
1107         switch (mls) {
1108         default: /* includes case 3 */
1109         case 4: ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 4); return;
1110         case 5: ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 5); return;
1111         case 6: ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 6); return;
1112         case 7: ZSTD_compressBlock_fast_generic(ctx, src, srcSize, 7); return;
1113         }
1114 }
1115 
1116 static void ZSTD_compressBlock_fast_extDict_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const U32 mls)
1117 {
1118         U32 *hashTable = ctx->hashTable;
1119         const U32 hBits = ctx->params.cParams.hashLog;
1120         seqStore_t *seqStorePtr = &(ctx->seqStore);
1121         const BYTE *const base = ctx->base;
1122         const BYTE *const dictBase = ctx->dictBase;
1123         const BYTE *const istart = (const BYTE *)src;
1124         const BYTE *ip = istart;
1125         const BYTE *anchor = istart;
1126         const U32 lowestIndex = ctx->lowLimit;
1127         const BYTE *const dictStart = dictBase + lowestIndex;
1128         const U32 dictLimit = ctx->dictLimit;
1129         const BYTE *const lowPrefixPtr = base + dictLimit;
1130         const BYTE *const dictEnd = dictBase + dictLimit;
1131         const BYTE *const iend = istart + srcSize;
1132         const BYTE *const ilimit = iend - 8;
1133         U32 offset_1 = ctx->rep[0], offset_2 = ctx->rep[1];
1134 
1135         /* Search Loop */
1136         while (ip < ilimit) { /* < instead of <=, because (ip+1) */
1137                 const size_t h = ZSTD_hashPtr(ip, hBits, mls);
1138                 const U32 matchIndex = hashTable[h];
1139                 const BYTE *matchBase = matchIndex < dictLimit ? dictBase : base;
1140                 const BYTE *match = matchBase + matchIndex;
1141                 const U32 curr = (U32)(ip - base);
1142                 const U32 repIndex = curr + 1 - offset_1; /* offset_1 expected <= curr +1 */
1143                 const BYTE *repBase = repIndex < dictLimit ? dictBase : base;
1144                 const BYTE *repMatch = repBase + repIndex;
1145                 size_t mLength;
1146                 hashTable[h] = curr; /* update hash table */
1147 
1148                 if ((((U32)((dictLimit - 1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex)) &&
1149                     (ZSTD_read32(repMatch) == ZSTD_read32(ip + 1))) {
1150                         const BYTE *repMatchEnd = repIndex < dictLimit ? dictEnd : iend;
1151                         mLength = ZSTD_count_2segments(ip + 1 + EQUAL_READ32, repMatch + EQUAL_READ32, iend, repMatchEnd, lowPrefixPtr) + EQUAL_READ32;
1152                         ip++;
1153                         ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH);
1154                 } else {
1155                         if ((matchIndex < lowestIndex) || (ZSTD_read32(match) != ZSTD_read32(ip))) {
1156                                 ip += ((ip - anchor) >> g_searchStrength) + 1;
1157                                 continue;
1158                         }
1159                         {
1160                                 const BYTE *matchEnd = matchIndex < dictLimit ? dictEnd : iend;
1161                                 const BYTE *lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr;
1162                                 U32 offset;
1163                                 mLength = ZSTD_count_2segments(ip + EQUAL_READ32, match + EQUAL_READ32, iend, matchEnd, lowPrefixPtr) + EQUAL_READ32;
1164                                 while (((ip > anchor) & (match > lowMatchPtr)) && (ip[-1] == match[-1])) {
1165                                         ip--;
1166                                         match--;
1167                                         mLength++;
1168                                 } /* catch up */
1169                                 offset = curr - matchIndex;
1170                                 offset_2 = offset_1;
1171                                 offset_1 = offset;
1172                                 ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);
1173                         }
1174                 }
1175 
1176                 /* found a match : store it */
1177                 ip += mLength;
1178                 anchor = ip;
1179 
1180                 if (ip <= ilimit) {
1181                         /* Fill Table */
1182                         hashTable[ZSTD_hashPtr(base + curr + 2, hBits, mls)] = curr + 2;
1183                         hashTable[ZSTD_hashPtr(ip - 2, hBits, mls)] = (U32)(ip - 2 - base);
1184                         /* check immediate repcode */
1185                         while (ip <= ilimit) {
1186                                 U32 const curr2 = (U32)(ip - base);
1187                                 U32 const repIndex2 = curr2 - offset_2;
1188                                 const BYTE *repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2;
1189                                 if ((((U32)((dictLimit - 1) - repIndex2) >= 3) & (repIndex2 > lowestIndex)) /* intentional overflow */
1190                                     && (ZSTD_read32(repMatch2) == ZSTD_read32(ip))) {
1191                                         const BYTE *const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend;
1192                                         size_t repLength2 =
1193                                             ZSTD_count_2segments(ip + EQUAL_READ32, repMatch2 + EQUAL_READ32, iend, repEnd2, lowPrefixPtr) + EQUAL_READ32;
1194                                         U32 tmpOffset = offset_2;
1195                                         offset_2 = offset_1;
1196                                         offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
1197                                         ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2 - MINMATCH);
1198                                         hashTable[ZSTD_hashPtr(ip, hBits, mls)] = curr2;
1199                                         ip += repLength2;
1200                                         anchor = ip;
1201                                         continue;
1202                                 }
1203                                 break;
1204                         }
1205                 }
1206         }
1207 
1208         /* save reps for next block */
1209         ctx->repToConfirm[0] = offset_1;
1210         ctx->repToConfirm[1] = offset_2;
1211 
1212         /* Last Literals */
1213         {
1214                 size_t const lastLLSize = iend - anchor;
1215                 memcpy(seqStorePtr->lit, anchor, lastLLSize);
1216                 seqStorePtr->lit += lastLLSize;
1217         }
1218 }
1219 
1220 static void ZSTD_compressBlock_fast_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
1221 {
1222         U32 const mls = ctx->params.cParams.searchLength;
1223         switch (mls) {
1224         default: /* includes case 3 */
1225         case 4: ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 4); return;
1226         case 5: ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 5); return;
1227         case 6: ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 6); return;
1228         case 7: ZSTD_compressBlock_fast_extDict_generic(ctx, src, srcSize, 7); return;
1229         }
1230 }
1231 
1232 /*-*************************************
1233 *  Double Fast
1234 ***************************************/
1235 static void ZSTD_fillDoubleHashTable(ZSTD_CCtx *cctx, const void *end, const U32 mls)
1236 {
1237         U32 *const hashLarge = cctx->hashTable;
1238         U32 const hBitsL = cctx->params.cParams.hashLog;
1239         U32 *const hashSmall = cctx->chainTable;
1240         U32 const hBitsS = cctx->params.cParams.chainLog;
1241         const BYTE *const base = cctx->base;
1242         const BYTE *ip = base + cctx->nextToUpdate;
1243         const BYTE *const iend = ((const BYTE *)end) - HASH_READ_SIZE;
1244         const size_t fastHashFillStep = 3;
1245 
1246         while (ip <= iend) {
1247                 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip - base);
1248                 hashLarge[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip - base);
1249                 ip += fastHashFillStep;
1250         }
1251 }
1252 
1253 FORCE_INLINE
1254 void ZSTD_compressBlock_doubleFast_generic(ZSTD_CCtx *cctx, const void *src, size_t srcSize, const U32 mls)
1255 {
1256         U32 *const hashLong = cctx->hashTable;
1257         const U32 hBitsL = cctx->params.cParams.hashLog;
1258         U32 *const hashSmall = cctx->chainTable;
1259         const U32 hBitsS = cctx->params.cParams.chainLog;
1260         seqStore_t *seqStorePtr = &(cctx->seqStore);
1261         const BYTE *const base = cctx->base;
1262         const BYTE *const istart = (const BYTE *)src;
1263         const BYTE *ip = istart;
1264         const BYTE *anchor = istart;
1265         const U32 lowestIndex = cctx->dictLimit;
1266         const BYTE *const lowest = base + lowestIndex;
1267         const BYTE *const iend = istart + srcSize;
1268         const BYTE *const ilimit = iend - HASH_READ_SIZE;
1269         U32 offset_1 = cctx->rep[0], offset_2 = cctx->rep[1];
1270         U32 offsetSaved = 0;
1271 
1272         /* init */
1273         ip += (ip == lowest);
1274         {
1275                 U32 const maxRep = (U32)(ip - lowest);
1276                 if (offset_2 > maxRep)
1277                         offsetSaved = offset_2, offset_2 = 0;
1278                 if (offset_1 > maxRep)
1279                         offsetSaved = offset_1, offset_1 = 0;
1280         }
1281 
1282         /* Main Search Loop */
1283         while (ip < ilimit) { /* < instead of <=, because repcode check at (ip+1) */
1284                 size_t mLength;
1285                 size_t const h2 = ZSTD_hashPtr(ip, hBitsL, 8);
1286                 size_t const h = ZSTD_hashPtr(ip, hBitsS, mls);
1287                 U32 const curr = (U32)(ip - base);
1288                 U32 const matchIndexL = hashLong[h2];
1289                 U32 const matchIndexS = hashSmall[h];
1290                 const BYTE *matchLong = base + matchIndexL;
1291                 const BYTE *match = base + matchIndexS;
1292                 hashLong[h2] = hashSmall[h] = curr; /* update hash tables */
1293 
1294                 if ((offset_1 > 0) & (ZSTD_read32(ip + 1 - offset_1) == ZSTD_read32(ip + 1))) { /* note : by construction, offset_1 <= curr */
1295                         mLength = ZSTD_count(ip + 1 + 4, ip + 1 + 4 - offset_1, iend) + 4;
1296                         ip++;
1297                         ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH);
1298                 } else {
1299                         U32 offset;
1300                         if ((matchIndexL > lowestIndex) && (ZSTD_read64(matchLong) == ZSTD_read64(ip))) {
1301                                 mLength = ZSTD_count(ip + 8, matchLong + 8, iend) + 8;
1302                                 offset = (U32)(ip - matchLong);
1303                                 while (((ip > anchor) & (matchLong > lowest)) && (ip[-1] == matchLong[-1])) {
1304                                         ip--;
1305                                         matchLong--;
1306                                         mLength++;
1307                                 } /* catch up */
1308                         } else if ((matchIndexS > lowestIndex) && (ZSTD_read32(match) == ZSTD_read32(ip))) {
1309                                 size_t const h3 = ZSTD_hashPtr(ip + 1, hBitsL, 8);
1310                                 U32 const matchIndex3 = hashLong[h3];
1311                                 const BYTE *match3 = base + matchIndex3;
1312                                 hashLong[h3] = curr + 1;
1313                                 if ((matchIndex3 > lowestIndex) && (ZSTD_read64(match3) == ZSTD_read64(ip + 1))) {
1314                                         mLength = ZSTD_count(ip + 9, match3 + 8, iend) + 8;
1315                                         ip++;
1316                                         offset = (U32)(ip - match3);
1317                                         while (((ip > anchor) & (match3 > lowest)) && (ip[-1] == match3[-1])) {
1318                                                 ip--;
1319                                                 match3--;
1320                                                 mLength++;
1321                                         } /* catch up */
1322                                 } else {
1323                                         mLength = ZSTD_count(ip + 4, match + 4, iend) + 4;
1324                                         offset = (U32)(ip - match);
1325                                         while (((ip > anchor) & (match > lowest)) && (ip[-1] == match[-1])) {
1326                                                 ip--;
1327                                                 match--;
1328                                                 mLength++;
1329                                         } /* catch up */
1330                                 }
1331                         } else {
1332                                 ip += ((ip - anchor) >> g_searchStrength) + 1;
1333                                 continue;
1334                         }
1335 
1336                         offset_2 = offset_1;
1337                         offset_1 = offset;
1338 
1339                         ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);
1340                 }
1341 
1342                 /* match found */
1343                 ip += mLength;
1344                 anchor = ip;
1345 
1346                 if (ip <= ilimit) {
1347                         /* Fill Table */
1348                         hashLong[ZSTD_hashPtr(base + curr + 2, hBitsL, 8)] = hashSmall[ZSTD_hashPtr(base + curr + 2, hBitsS, mls)] =
1349                             curr + 2; /* here because curr+2 could be > iend-8 */
1350                         hashLong[ZSTD_hashPtr(ip - 2, hBitsL, 8)] = hashSmall[ZSTD_hashPtr(ip - 2, hBitsS, mls)] = (U32)(ip - 2 - base);
1351 
1352                         /* check immediate repcode */
1353                         while ((ip <= ilimit) && ((offset_2 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) {
1354                                 /* store sequence */
1355                                 size_t const rLength = ZSTD_count(ip + 4, ip + 4 - offset_2, iend) + 4;
1356                                 {
1357                                         U32 const tmpOff = offset_2;
1358                                         offset_2 = offset_1;
1359                                         offset_1 = tmpOff;
1360                                 } /* swap offset_2 <=> offset_1 */
1361                                 hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = (U32)(ip - base);
1362                                 hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = (U32)(ip - base);
1363                                 ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, rLength - MINMATCH);
1364                                 ip += rLength;
1365                                 anchor = ip;
1366                                 continue; /* faster when present ... (?) */
1367                         }
1368                 }
1369         }
1370 
1371         /* save reps for next block */
1372         cctx->repToConfirm[0] = offset_1 ? offset_1 : offsetSaved;
1373         cctx->repToConfirm[1] = offset_2 ? offset_2 : offsetSaved;
1374 
1375         /* Last Literals */
1376         {
1377                 size_t const lastLLSize = iend - anchor;
1378                 memcpy(seqStorePtr->lit, anchor, lastLLSize);
1379                 seqStorePtr->lit += lastLLSize;
1380         }
1381 }
1382 
1383 static void ZSTD_compressBlock_doubleFast(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
1384 {
1385         const U32 mls = ctx->params.cParams.searchLength;
1386         switch (mls) {
1387         default: /* includes case 3 */
1388         case 4: ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 4); return;
1389         case 5: ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 5); return;
1390         case 6: ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 6); return;
1391         case 7: ZSTD_compressBlock_doubleFast_generic(ctx, src, srcSize, 7); return;
1392         }
1393 }
1394 
1395 static void ZSTD_compressBlock_doubleFast_extDict_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const U32 mls)
1396 {
1397         U32 *const hashLong = ctx->hashTable;
1398         U32 const hBitsL = ctx->params.cParams.hashLog;
1399         U32 *const hashSmall = ctx->chainTable;
1400         U32 const hBitsS = ctx->params.cParams.chainLog;
1401         seqStore_t *seqStorePtr = &(ctx->seqStore);
1402         const BYTE *const base = ctx->base;
1403         const BYTE *const dictBase = ctx->dictBase;
1404         const BYTE *const istart = (const BYTE *)src;
1405         const BYTE *ip = istart;
1406         const BYTE *anchor = istart;
1407         const U32 lowestIndex = ctx->lowLimit;
1408         const BYTE *const dictStart = dictBase + lowestIndex;
1409         const U32 dictLimit = ctx->dictLimit;
1410         const BYTE *const lowPrefixPtr = base + dictLimit;
1411         const BYTE *const dictEnd = dictBase + dictLimit;
1412         const BYTE *const iend = istart + srcSize;
1413         const BYTE *const ilimit = iend - 8;
1414         U32 offset_1 = ctx->rep[0], offset_2 = ctx->rep[1];
1415 
1416         /* Search Loop */
1417         while (ip < ilimit) { /* < instead of <=, because (ip+1) */
1418                 const size_t hSmall = ZSTD_hashPtr(ip, hBitsS, mls);
1419                 const U32 matchIndex = hashSmall[hSmall];
1420                 const BYTE *matchBase = matchIndex < dictLimit ? dictBase : base;
1421                 const BYTE *match = matchBase + matchIndex;
1422 
1423                 const size_t hLong = ZSTD_hashPtr(ip, hBitsL, 8);
1424                 const U32 matchLongIndex = hashLong[hLong];
1425                 const BYTE *matchLongBase = matchLongIndex < dictLimit ? dictBase : base;
1426                 const BYTE *matchLong = matchLongBase + matchLongIndex;
1427 
1428                 const U32 curr = (U32)(ip - base);
1429                 const U32 repIndex = curr + 1 - offset_1; /* offset_1 expected <= curr +1 */
1430                 const BYTE *repBase = repIndex < dictLimit ? dictBase : base;
1431                 const BYTE *repMatch = repBase + repIndex;
1432                 size_t mLength;
1433                 hashSmall[hSmall] = hashLong[hLong] = curr; /* update hash table */
1434 
1435                 if ((((U32)((dictLimit - 1) - repIndex) >= 3) /* intentional underflow */ & (repIndex > lowestIndex)) &&
1436                     (ZSTD_read32(repMatch) == ZSTD_read32(ip + 1))) {
1437                         const BYTE *repMatchEnd = repIndex < dictLimit ? dictEnd : iend;
1438                         mLength = ZSTD_count_2segments(ip + 1 + 4, repMatch + 4, iend, repMatchEnd, lowPrefixPtr) + 4;
1439                         ip++;
1440                         ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH);
1441                 } else {
1442                         if ((matchLongIndex > lowestIndex) && (ZSTD_read64(matchLong) == ZSTD_read64(ip))) {
1443                                 const BYTE *matchEnd = matchLongIndex < dictLimit ? dictEnd : iend;
1444                                 const BYTE *lowMatchPtr = matchLongIndex < dictLimit ? dictStart : lowPrefixPtr;
1445                                 U32 offset;
1446                                 mLength = ZSTD_count_2segments(ip + 8, matchLong + 8, iend, matchEnd, lowPrefixPtr) + 8;
1447                                 offset = curr - matchLongIndex;
1448                                 while (((ip > anchor) & (matchLong > lowMatchPtr)) && (ip[-1] == matchLong[-1])) {
1449                                         ip--;
1450                                         matchLong--;
1451                                         mLength++;
1452                                 } /* catch up */
1453                                 offset_2 = offset_1;
1454                                 offset_1 = offset;
1455                                 ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);
1456 
1457                         } else if ((matchIndex > lowestIndex) && (ZSTD_read32(match) == ZSTD_read32(ip))) {
1458                                 size_t const h3 = ZSTD_hashPtr(ip + 1, hBitsL, 8);
1459                                 U32 const matchIndex3 = hashLong[h3];
1460                                 const BYTE *const match3Base = matchIndex3 < dictLimit ? dictBase : base;
1461                                 const BYTE *match3 = match3Base + matchIndex3;
1462                                 U32 offset;
1463                                 hashLong[h3] = curr + 1;
1464                                 if ((matchIndex3 > lowestIndex) && (ZSTD_read64(match3) == ZSTD_read64(ip + 1))) {
1465                                         const BYTE *matchEnd = matchIndex3 < dictLimit ? dictEnd : iend;
1466                                         const BYTE *lowMatchPtr = matchIndex3 < dictLimit ? dictStart : lowPrefixPtr;
1467                                         mLength = ZSTD_count_2segments(ip + 9, match3 + 8, iend, matchEnd, lowPrefixPtr) + 8;
1468                                         ip++;
1469                                         offset = curr + 1 - matchIndex3;
1470                                         while (((ip > anchor) & (match3 > lowMatchPtr)) && (ip[-1] == match3[-1])) {
1471                                                 ip--;
1472                                                 match3--;
1473                                                 mLength++;
1474                                         } /* catch up */
1475                                 } else {
1476                                         const BYTE *matchEnd = matchIndex < dictLimit ? dictEnd : iend;
1477                                         const BYTE *lowMatchPtr = matchIndex < dictLimit ? dictStart : lowPrefixPtr;
1478                                         mLength = ZSTD_count_2segments(ip + 4, match + 4, iend, matchEnd, lowPrefixPtr) + 4;
1479                                         offset = curr - matchIndex;
1480                                         while (((ip > anchor) & (match > lowMatchPtr)) && (ip[-1] == match[-1])) {
1481                                                 ip--;
1482                                                 match--;
1483                                                 mLength++;
1484                                         } /* catch up */
1485                                 }
1486                                 offset_2 = offset_1;
1487                                 offset_1 = offset;
1488                                 ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, offset + ZSTD_REP_MOVE, mLength - MINMATCH);
1489 
1490                         } else {
1491                                 ip += ((ip - anchor) >> g_searchStrength) + 1;
1492                                 continue;
1493                         }
1494                 }
1495 
1496                 /* found a match : store it */
1497                 ip += mLength;
1498                 anchor = ip;
1499 
1500                 if (ip <= ilimit) {
1501                         /* Fill Table */
1502                         hashSmall[ZSTD_hashPtr(base + curr + 2, hBitsS, mls)] = curr + 2;
1503                         hashLong[ZSTD_hashPtr(base + curr + 2, hBitsL, 8)] = curr + 2;
1504                         hashSmall[ZSTD_hashPtr(ip - 2, hBitsS, mls)] = (U32)(ip - 2 - base);
1505                         hashLong[ZSTD_hashPtr(ip - 2, hBitsL, 8)] = (U32)(ip - 2 - base);
1506                         /* check immediate repcode */
1507                         while (ip <= ilimit) {
1508                                 U32 const curr2 = (U32)(ip - base);
1509                                 U32 const repIndex2 = curr2 - offset_2;
1510                                 const BYTE *repMatch2 = repIndex2 < dictLimit ? dictBase + repIndex2 : base + repIndex2;
1511                                 if ((((U32)((dictLimit - 1) - repIndex2) >= 3) & (repIndex2 > lowestIndex)) /* intentional overflow */
1512                                     && (ZSTD_read32(repMatch2) == ZSTD_read32(ip))) {
1513                                         const BYTE *const repEnd2 = repIndex2 < dictLimit ? dictEnd : iend;
1514                                         size_t const repLength2 =
1515                                             ZSTD_count_2segments(ip + EQUAL_READ32, repMatch2 + EQUAL_READ32, iend, repEnd2, lowPrefixPtr) + EQUAL_READ32;
1516                                         U32 tmpOffset = offset_2;
1517                                         offset_2 = offset_1;
1518                                         offset_1 = tmpOffset; /* swap offset_2 <=> offset_1 */
1519                                         ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, repLength2 - MINMATCH);
1520                                         hashSmall[ZSTD_hashPtr(ip, hBitsS, mls)] = curr2;
1521                                         hashLong[ZSTD_hashPtr(ip, hBitsL, 8)] = curr2;
1522                                         ip += repLength2;
1523                                         anchor = ip;
1524                                         continue;
1525                                 }
1526                                 break;
1527                         }
1528                 }
1529         }
1530 
1531         /* save reps for next block */
1532         ctx->repToConfirm[0] = offset_1;
1533         ctx->repToConfirm[1] = offset_2;
1534 
1535         /* Last Literals */
1536         {
1537                 size_t const lastLLSize = iend - anchor;
1538                 memcpy(seqStorePtr->lit, anchor, lastLLSize);
1539                 seqStorePtr->lit += lastLLSize;
1540         }
1541 }
1542 
1543 static void ZSTD_compressBlock_doubleFast_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
1544 {
1545         U32 const mls = ctx->params.cParams.searchLength;
1546         switch (mls) {
1547         default: /* includes case 3 */
1548         case 4: ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 4); return;
1549         case 5: ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 5); return;
1550         case 6: ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 6); return;
1551         case 7: ZSTD_compressBlock_doubleFast_extDict_generic(ctx, src, srcSize, 7); return;
1552         }
1553 }
1554 
1555 /*-*************************************
1556 *  Binary Tree search
1557 ***************************************/
1558 /** ZSTD_insertBt1() : add one or multiple positions to tree.
1559 *   ip : assumed <= iend-8 .
1560 *   @return : nb of positions added */
1561 static U32 ZSTD_insertBt1(ZSTD_CCtx *zc, const BYTE *const ip, const U32 mls, const BYTE *const iend, U32 nbCompares, U32 extDict)
1562 {
1563         U32 *const hashTable = zc->hashTable;
1564         U32 const hashLog = zc->params.cParams.hashLog;
1565         size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
1566         U32 *const bt = zc->chainTable;
1567         U32 const btLog = zc->params.cParams.chainLog - 1;
1568         U32 const btMask = (1 << btLog) - 1;
1569         U32 matchIndex = hashTable[h];
1570         size_t commonLengthSmaller = 0, commonLengthLarger = 0;
1571         const BYTE *const base = zc->base;
1572         const BYTE *const dictBase = zc->dictBase;
1573         const U32 dictLimit = zc->dictLimit;
1574         const BYTE *const dictEnd = dictBase + dictLimit;
1575         const BYTE *const prefixStart = base + dictLimit;
1576         const BYTE *match;
1577         const U32 curr = (U32)(ip - base);
1578         const U32 btLow = btMask >= curr ? 0 : curr - btMask;
1579         U32 *smallerPtr = bt + 2 * (curr & btMask);
1580         U32 *largerPtr = smallerPtr + 1;
1581         U32 dummy32; /* to be nullified at the end */
1582         U32 const windowLow = zc->lowLimit;
1583         U32 matchEndIdx = curr + 8;
1584         size_t bestLength = 8;
1585 
1586         hashTable[h] = curr; /* Update Hash Table */
1587 
1588         while (nbCompares-- && (matchIndex > windowLow)) {
1589                 U32 *const nextPtr = bt + 2 * (matchIndex & btMask);
1590                 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
1591 
1592                 if ((!extDict) || (matchIndex + matchLength >= dictLimit)) {
1593                         match = base + matchIndex;
1594                         if (match[matchLength] == ip[matchLength])
1595                                 matchLength += ZSTD_count(ip + matchLength + 1, match + matchLength + 1, iend) + 1;
1596                 } else {
1597                         match = dictBase + matchIndex;
1598                         matchLength += ZSTD_count_2segments(ip + matchLength, match + matchLength, iend, dictEnd, prefixStart);
1599                         if (matchIndex + matchLength >= dictLimit)
1600                                 match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
1601                 }
1602 
1603                 if (matchLength > bestLength) {
1604                         bestLength = matchLength;
1605                         if (matchLength > matchEndIdx - matchIndex)
1606                                 matchEndIdx = matchIndex + (U32)matchLength;
1607                 }
1608 
1609                 if (ip + matchLength == iend) /* equal : no way to know if inf or sup */
1610                         break;                /* drop , to guarantee consistency ; miss a bit of compression, but other solutions can corrupt the tree */
1611 
1612                 if (match[matchLength] < ip[matchLength]) { /* necessarily within correct buffer */
1613                         /* match is smaller than curr */
1614                         *smallerPtr = matchIndex;         /* update smaller idx */
1615                         commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
1616                         if (matchIndex <= btLow) {
1617                                 smallerPtr = &dummy32;
1618                                 break;
1619                         }                         /* beyond tree size, stop the search */
1620                         smallerPtr = nextPtr + 1; /* new "smaller" => larger of match */
1621                         matchIndex = nextPtr[1];  /* new matchIndex larger than previous (closer to curr) */
1622                 } else {
1623                         /* match is larger than curr */
1624                         *largerPtr = matchIndex;
1625                         commonLengthLarger = matchLength;
1626                         if (matchIndex <= btLow) {
1627                                 largerPtr = &dummy32;
1628                                 break;
1629                         } /* beyond tree size, stop the search */
1630                         largerPtr = nextPtr;
1631                         matchIndex = nextPtr[0];
1632                 }
1633         }
1634 
1635         *smallerPtr = *largerPtr = 0;
1636         if (bestLength > 384)
1637                 return MIN(192, (U32)(bestLength - 384)); /* speed optimization */
1638         if (matchEndIdx > curr + 8)
1639                 return matchEndIdx - curr - 8;
1640         return 1;
1641 }
1642 
1643 static size_t ZSTD_insertBtAndFindBestMatch(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iend, size_t *offsetPtr, U32 nbCompares, const U32 mls,
1644                                             U32 extDict)
1645 {
1646         U32 *const hashTable = zc->hashTable;
1647         U32 const hashLog = zc->params.cParams.hashLog;
1648         size_t const h = ZSTD_hashPtr(ip, hashLog, mls);
1649         U32 *const bt = zc->chainTable;
1650         U32 const btLog = zc->params.cParams.chainLog - 1;
1651         U32 const btMask = (1 << btLog) - 1;
1652         U32 matchIndex = hashTable[h];
1653         size_t commonLengthSmaller = 0, commonLengthLarger = 0;
1654         const BYTE *const base = zc->base;
1655         const BYTE *const dictBase = zc->dictBase;
1656         const U32 dictLimit = zc->dictLimit;
1657         const BYTE *const dictEnd = dictBase + dictLimit;
1658         const BYTE *const prefixStart = base + dictLimit;
1659         const U32 curr = (U32)(ip - base);
1660         const U32 btLow = btMask >= curr ? 0 : curr - btMask;
1661         const U32 windowLow = zc->lowLimit;
1662         U32 *smallerPtr = bt + 2 * (curr & btMask);
1663         U32 *largerPtr = bt + 2 * (curr & btMask) + 1;
1664         U32 matchEndIdx = curr + 8;
1665         U32 dummy32; /* to be nullified at the end */
1666         size_t bestLength = 0;
1667 
1668         hashTable[h] = curr; /* Update Hash Table */
1669 
1670         while (nbCompares-- && (matchIndex > windowLow)) {
1671                 U32 *const nextPtr = bt + 2 * (matchIndex & btMask);
1672                 size_t matchLength = MIN(commonLengthSmaller, commonLengthLarger); /* guaranteed minimum nb of common bytes */
1673                 const BYTE *match;
1674 
1675                 if ((!extDict) || (matchIndex + matchLength >= dictLimit)) {
1676                         match = base + matchIndex;
1677                         if (match[matchLength] == ip[matchLength])
1678                                 matchLength += ZSTD_count(ip + matchLength + 1, match + matchLength + 1, iend) + 1;
1679                 } else {
1680                         match = dictBase + matchIndex;
1681                         matchLength += ZSTD_count_2segments(ip + matchLength, match + matchLength, iend, dictEnd, prefixStart);
1682                         if (matchIndex + matchLength >= dictLimit)
1683                                 match = base + matchIndex; /* to prepare for next usage of match[matchLength] */
1684                 }
1685 
1686                 if (matchLength > bestLength) {
1687                         if (matchLength > matchEndIdx - matchIndex)
1688                                 matchEndIdx = matchIndex + (U32)matchLength;
1689                         if ((4 * (int)(matchLength - bestLength)) > (int)(ZSTD_highbit32(curr - matchIndex + 1) - ZSTD_highbit32((U32)offsetPtr[0] + 1)))
1690                                 bestLength = matchLength, *offsetPtr = ZSTD_REP_MOVE + curr - matchIndex;
1691                         if (ip + matchLength == iend) /* equal : no way to know if inf or sup */
1692                                 break;                /* drop, to guarantee consistency (miss a little bit of compression) */
1693                 }
1694 
1695                 if (match[matchLength] < ip[matchLength]) {
1696                         /* match is smaller than curr */
1697                         *smallerPtr = matchIndex;         /* update smaller idx */
1698                         commonLengthSmaller = matchLength; /* all smaller will now have at least this guaranteed common length */
1699                         if (matchIndex <= btLow) {
1700                                 smallerPtr = &dummy32;
1701                                 break;
1702                         }                         /* beyond tree size, stop the search */
1703                         smallerPtr = nextPtr + 1; /* new "smaller" => larger of match */
1704                         matchIndex = nextPtr[1];  /* new matchIndex larger than previous (closer to curr) */
1705                 } else {
1706                         /* match is larger than curr */
1707                         *largerPtr = matchIndex;
1708                         commonLengthLarger = matchLength;
1709                         if (matchIndex <= btLow) {
1710                                 largerPtr = &dummy32;
1711                                 break;
1712                         } /* beyond tree size, stop the search */
1713                         largerPtr = nextPtr;
1714                         matchIndex = nextPtr[0];
1715                 }
1716         }
1717 
1718         *smallerPtr = *largerPtr = 0;
1719 
1720         zc->nextToUpdate = (matchEndIdx > curr + 8) ? matchEndIdx - 8 : curr + 1;
1721         return bestLength;
1722 }
1723 
1724 static void ZSTD_updateTree(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iend, const U32 nbCompares, const U32 mls)
1725 {
1726         const BYTE *const base = zc->base;
1727         const U32 target = (U32)(ip - base);
1728         U32 idx = zc->nextToUpdate;
1729 
1730         while (idx < target)
1731                 idx += ZSTD_insertBt1(zc, base + idx, mls, iend, nbCompares, 0);
1732 }
1733 
1734 /** ZSTD_BtFindBestMatch() : Tree updater, providing best match */
1735 static size_t ZSTD_BtFindBestMatch(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts, const U32 mls)
1736 {
1737         if (ip < zc->base + zc->nextToUpdate)
1738                 return 0; /* skipped area */
1739         ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
1740         return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 0);
1741 }
1742 
1743 static size_t ZSTD_BtFindBestMatch_selectMLS(ZSTD_CCtx *zc, /* Index table will be updated */
1744                                              const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts, const U32 matchLengthSearch)
1745 {
1746         switch (matchLengthSearch) {
1747         default: /* includes case 3 */
1748         case 4: return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4);
1749         case 5: return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5);
1750         case 7:
1751         case 6: return ZSTD_BtFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6);
1752         }
1753 }
1754 
1755 static void ZSTD_updateTree_extDict(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iend, const U32 nbCompares, const U32 mls)
1756 {
1757         const BYTE *const base = zc->base;
1758         const U32 target = (U32)(ip - base);
1759         U32 idx = zc->nextToUpdate;
1760 
1761         while (idx < target)
1762                 idx += ZSTD_insertBt1(zc, base + idx, mls, iend, nbCompares, 1);
1763 }
1764 
1765 /** Tree updater, providing best match */
1766 static size_t ZSTD_BtFindBestMatch_extDict(ZSTD_CCtx *zc, const BYTE *const ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts,
1767                                            const U32 mls)
1768 {
1769         if (ip < zc->base + zc->nextToUpdate)
1770                 return 0; /* skipped area */
1771         ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
1772         return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1);
1773 }
1774 
1775 static size_t ZSTD_BtFindBestMatch_selectMLS_extDict(ZSTD_CCtx *zc, /* Index table will be updated */
1776                                                      const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts,
1777                                                      const U32 matchLengthSearch)
1778 {
1779         switch (matchLengthSearch) {
1780         default: /* includes case 3 */
1781         case 4: return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4);
1782         case 5: return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5);
1783         case 7:
1784         case 6: return ZSTD_BtFindBestMatch_extDict(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6);
1785         }
1786 }
1787 
1788 /* *********************************
1789 *  Hash Chain
1790 ***********************************/
1791 #define NEXT_IN_CHAIN(d, mask) chainTable[(d)&mask]
1792 
1793 /* Update chains up to ip (excluded)
1794    Assumption : always within prefix (i.e. not within extDict) */
1795 FORCE_INLINE
1796 U32 ZSTD_insertAndFindFirstIndex(ZSTD_CCtx *zc, const BYTE *ip, U32 mls)
1797 {
1798         U32 *const hashTable = zc->hashTable;
1799         const U32 hashLog = zc->params.cParams.hashLog;
1800         U32 *const chainTable = zc->chainTable;
1801         const U32 chainMask = (1 << zc->params.cParams.chainLog) - 1;
1802         const BYTE *const base = zc->base;
1803         const U32 target = (U32)(ip - base);
1804         U32 idx = zc->nextToUpdate;
1805 
1806         while (idx < target) { /* catch up */
1807                 size_t const h = ZSTD_hashPtr(base + idx, hashLog, mls);
1808                 NEXT_IN_CHAIN(idx, chainMask) = hashTable[h];
1809                 hashTable[h] = idx;
1810                 idx++;
1811         }
1812 
1813         zc->nextToUpdate = target;
1814         return hashTable[ZSTD_hashPtr(ip, hashLog, mls)];
1815 }
1816 
1817 /* inlining is important to hardwire a hot branch (template emulation) */
1818 FORCE_INLINE
1819 size_t ZSTD_HcFindBestMatch_generic(ZSTD_CCtx *zc, /* Index table will be updated */
1820                                     const BYTE *const ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts, const U32 mls,
1821                                     const U32 extDict)
1822 {
1823         U32 *const chainTable = zc->chainTable;
1824         const U32 chainSize = (1 << zc->params.cParams.chainLog);
1825         const U32 chainMask = chainSize - 1;
1826         const BYTE *const base = zc->base;
1827         const BYTE *const dictBase = zc->dictBase;
1828         const U32 dictLimit = zc->dictLimit;
1829         const BYTE *const prefixStart = base + dictLimit;
1830         const BYTE *const dictEnd = dictBase + dictLimit;
1831         const U32 lowLimit = zc->lowLimit;
1832         const U32 curr = (U32)(ip - base);
1833         const U32 minChain = curr > chainSize ? curr - chainSize : 0;
1834         int nbAttempts = maxNbAttempts;
1835         size_t ml = EQUAL_READ32 - 1;
1836 
1837         /* HC4 match finder */
1838         U32 matchIndex = ZSTD_insertAndFindFirstIndex(zc, ip, mls);
1839 
1840         for (; (matchIndex > lowLimit) & (nbAttempts > 0); nbAttempts--) {
1841                 const BYTE *match;
1842                 size_t currMl = 0;
1843                 if ((!extDict) || matchIndex >= dictLimit) {
1844                         match = base + matchIndex;
1845                         if (match[ml] == ip[ml]) /* potentially better */
1846                                 currMl = ZSTD_count(ip, match, iLimit);
1847                 } else {
1848                         match = dictBase + matchIndex;
1849                         if (ZSTD_read32(match) == ZSTD_read32(ip)) /* assumption : matchIndex <= dictLimit-4 (by table construction) */
1850                                 currMl = ZSTD_count_2segments(ip + EQUAL_READ32, match + EQUAL_READ32, iLimit, dictEnd, prefixStart) + EQUAL_READ32;
1851                 }
1852 
1853                 /* save best solution */
1854                 if (currMl > ml) {
1855                         ml = currMl;
1856                         *offsetPtr = curr - matchIndex + ZSTD_REP_MOVE;
1857                         if (ip + currMl == iLimit)
1858                                 break; /* best possible, and avoid read overflow*/
1859                 }
1860 
1861                 if (matchIndex <= minChain)
1862                         break;
1863                 matchIndex = NEXT_IN_CHAIN(matchIndex, chainMask);
1864         }
1865 
1866         return ml;
1867 }
1868 
1869 FORCE_INLINE size_t ZSTD_HcFindBestMatch_selectMLS(ZSTD_CCtx *zc, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts,
1870                                                    const U32 matchLengthSearch)
1871 {
1872         switch (matchLengthSearch) {
1873         default: /* includes case 3 */
1874         case 4: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 0);
1875         case 5: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 0);
1876         case 7:
1877         case 6: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 0);
1878         }
1879 }
1880 
1881 FORCE_INLINE size_t ZSTD_HcFindBestMatch_extDict_selectMLS(ZSTD_CCtx *zc, const BYTE *ip, const BYTE *const iLimit, size_t *offsetPtr, const U32 maxNbAttempts,
1882                                                            const U32 matchLengthSearch)
1883 {
1884         switch (matchLengthSearch) {
1885         default: /* includes case 3 */
1886         case 4: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 4, 1);
1887         case 5: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 5, 1);
1888         case 7:
1889         case 6: return ZSTD_HcFindBestMatch_generic(zc, ip, iLimit, offsetPtr, maxNbAttempts, 6, 1);
1890         }
1891 }
1892 
1893 /* *******************************
1894 *  Common parser - lazy strategy
1895 *********************************/
1896 FORCE_INLINE
1897 void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const U32 searchMethod, const U32 depth)
1898 {
1899         seqStore_t *seqStorePtr = &(ctx->seqStore);
1900         const BYTE *const istart = (const BYTE *)src;
1901         const BYTE *ip = istart;
1902         const BYTE *anchor = istart;
1903         const BYTE *const iend = istart + srcSize;
1904         const BYTE *const ilimit = iend - 8;
1905         const BYTE *const base = ctx->base + ctx->dictLimit;
1906 
1907         U32 const maxSearches = 1 << ctx->params.cParams.searchLog;
1908         U32 const mls = ctx->params.cParams.searchLength;
1909 
1910         typedef size_t (*searchMax_f)(ZSTD_CCtx * zc, const BYTE *ip, const BYTE *iLimit, size_t *offsetPtr, U32 maxNbAttempts, U32 matchLengthSearch);
1911         searchMax_f const searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS : ZSTD_HcFindBestMatch_selectMLS;
1912         U32 offset_1 = ctx->rep[0], offset_2 = ctx->rep[1], savedOffset = 0;
1913 
1914         /* init */
1915         ip += (ip == base);
1916         ctx->nextToUpdate3 = ctx->nextToUpdate;
1917         {
1918                 U32 const maxRep = (U32)(ip - base);
1919                 if (offset_2 > maxRep)
1920                         savedOffset = offset_2, offset_2 = 0;
1921                 if (offset_1 > maxRep)
1922                         savedOffset = offset_1, offset_1 = 0;
1923         }
1924 
1925         /* Match Loop */
1926         while (ip < ilimit) {
1927                 size_t matchLength = 0;
1928                 size_t offset = 0;
1929                 const BYTE *start = ip + 1;
1930 
1931                 /* check repCode */
1932                 if ((offset_1 > 0) & (ZSTD_read32(ip + 1) == ZSTD_read32(ip + 1 - offset_1))) {
1933                         /* repcode : we take it */
1934                         matchLength = ZSTD_count(ip + 1 + EQUAL_READ32, ip + 1 + EQUAL_READ32 - offset_1, iend) + EQUAL_READ32;
1935                         if (depth == 0)
1936                                 goto _storeSequence;
1937                 }
1938 
1939                 /* first search (depth 0) */
1940                 {
1941                         size_t offsetFound = 99999999;
1942                         size_t const ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
1943                         if (ml2 > matchLength)
1944                                 matchLength = ml2, start = ip, offset = offsetFound;
1945                 }
1946 
1947                 if (matchLength < EQUAL_READ32) {
1948                         ip += ((ip - anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */
1949                         continue;
1950                 }
1951 
1952                 /* let's try to find a better solution */
1953                 if (depth >= 1)
1954                         while (ip < ilimit) {
1955                                 ip++;
1956                                 if ((offset) && ((offset_1 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_1)))) {
1957                                         size_t const mlRep = ZSTD_count(ip + EQUAL_READ32, ip + EQUAL_READ32 - offset_1, iend) + EQUAL_READ32;
1958                                         int const gain2 = (int)(mlRep * 3);
1959                                         int const gain1 = (int)(matchLength * 3 - ZSTD_highbit32((U32)offset + 1) + 1);
1960                                         if ((mlRep >= EQUAL_READ32) && (gain2 > gain1))
1961                                                 matchLength = mlRep, offset = 0, start = ip;
1962                                 }
1963                                 {
1964                                         size_t offset2 = 99999999;
1965                                         size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
1966                                         int const gain2 = (int)(ml2 * 4 - ZSTD_highbit32((U32)offset2 + 1)); /* raw approx */
1967                                         int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 4);
1968                                         if ((ml2 >= EQUAL_READ32) && (gain2 > gain1)) {
1969                                                 matchLength = ml2, offset = offset2, start = ip;
1970                                                 continue; /* search a better one */
1971                                         }
1972                                 }
1973 
1974                                 /* let's find an even better one */
1975                                 if ((depth == 2) && (ip < ilimit)) {
1976                                         ip++;
1977                                         if ((offset) && ((offset_1 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_1)))) {
1978                                                 size_t const ml2 = ZSTD_count(ip + EQUAL_READ32, ip + EQUAL_READ32 - offset_1, iend) + EQUAL_READ32;
1979                                                 int const gain2 = (int)(ml2 * 4);
1980                                                 int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 1);
1981                                                 if ((ml2 >= EQUAL_READ32) && (gain2 > gain1))
1982                                                         matchLength = ml2, offset = 0, start = ip;
1983                                         }
1984                                         {
1985                                                 size_t offset2 = 99999999;
1986                                                 size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
1987                                                 int const gain2 = (int)(ml2 * 4 - ZSTD_highbit32((U32)offset2 + 1)); /* raw approx */
1988                                                 int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 7);
1989                                                 if ((ml2 >= EQUAL_READ32) && (gain2 > gain1)) {
1990                                                         matchLength = ml2, offset = offset2, start = ip;
1991                                                         continue;
1992                                                 }
1993                                         }
1994                                 }
1995                                 break; /* nothing found : store previous solution */
1996                         }
1997 
1998                 /* NOTE:
1999                  * start[-offset+ZSTD_REP_MOVE-1] is undefined behavior.
2000                  * (-offset+ZSTD_REP_MOVE-1) is unsigned, and is added to start, which
2001                  * overflows the pointer, which is undefined behavior.
2002                  */
2003                 /* catch up */
2004                 if (offset) {
2005                         while ((start > anchor) && (start > base + offset - ZSTD_REP_MOVE) &&
2006                                (start[-1] == (start-offset+ZSTD_REP_MOVE)[-1])) /* only search for offset within prefix */
2007                         {
2008                                 start--;
2009                                 matchLength++;
2010                         }
2011                         offset_2 = offset_1;
2012                         offset_1 = (U32)(offset - ZSTD_REP_MOVE);
2013                 }
2014 
2015         /* store sequence */
2016 _storeSequence:
2017                 {
2018                         size_t const litLength = start - anchor;
2019                         ZSTD_storeSeq(seqStorePtr, litLength, anchor, (U32)offset, matchLength - MINMATCH);
2020                         anchor = ip = start + matchLength;
2021                 }
2022 
2023                 /* check immediate repcode */
2024                 while ((ip <= ilimit) && ((offset_2 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) {
2025                         /* store sequence */
2026                         matchLength = ZSTD_count(ip + EQUAL_READ32, ip + EQUAL_READ32 - offset_2, iend) + EQUAL_READ32;
2027                         offset = offset_2;
2028                         offset_2 = offset_1;
2029                         offset_1 = (U32)offset; /* swap repcodes */
2030                         ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, matchLength - MINMATCH);
2031                         ip += matchLength;
2032                         anchor = ip;
2033                         continue; /* faster when present ... (?) */
2034                 }
2035         }
2036 
2037         /* Save reps for next block */
2038         ctx->repToConfirm[0] = offset_1 ? offset_1 : savedOffset;
2039         ctx->repToConfirm[1] = offset_2 ? offset_2 : savedOffset;
2040 
2041         /* Last Literals */
2042         {
2043                 size_t const lastLLSize = iend - anchor;
2044                 memcpy(seqStorePtr->lit, anchor, lastLLSize);
2045                 seqStorePtr->lit += lastLLSize;
2046         }
2047 }
2048 
2049 static void ZSTD_compressBlock_btlazy2(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 1, 2); }
2050 
2051 static void ZSTD_compressBlock_lazy2(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 2); }
2052 
2053 static void ZSTD_compressBlock_lazy(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 1); }
2054 
2055 static void ZSTD_compressBlock_greedy(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_generic(ctx, src, srcSize, 0, 0); }
2056 
2057 FORCE_INLINE
2058 void ZSTD_compressBlock_lazy_extDict_generic(ZSTD_CCtx *ctx, const void *src, size_t srcSize, const U32 searchMethod, const U32 depth)
2059 {
2060         seqStore_t *seqStorePtr = &(ctx->seqStore);
2061         const BYTE *const istart = (const BYTE *)src;
2062         const BYTE *ip = istart;
2063         const BYTE *anchor = istart;
2064         const BYTE *const iend = istart + srcSize;
2065         const BYTE *const ilimit = iend - 8;
2066         const BYTE *const base = ctx->base;
2067         const U32 dictLimit = ctx->dictLimit;
2068         const U32 lowestIndex = ctx->lowLimit;
2069         const BYTE *const prefixStart = base + dictLimit;
2070         const BYTE *const dictBase = ctx->dictBase;
2071         const BYTE *const dictEnd = dictBase + dictLimit;
2072         const BYTE *const dictStart = dictBase + ctx->lowLimit;
2073 
2074         const U32 maxSearches = 1 << ctx->params.cParams.searchLog;
2075         const U32 mls = ctx->params.cParams.searchLength;
2076 
2077         typedef size_t (*searchMax_f)(ZSTD_CCtx * zc, const BYTE *ip, const BYTE *iLimit, size_t *offsetPtr, U32 maxNbAttempts, U32 matchLengthSearch);
2078         searchMax_f searchMax = searchMethod ? ZSTD_BtFindBestMatch_selectMLS_extDict : ZSTD_HcFindBestMatch_extDict_selectMLS;
2079 
2080         U32 offset_1 = ctx->rep[0], offset_2 = ctx->rep[1];
2081 
2082         /* init */
2083         ctx->nextToUpdate3 = ctx->nextToUpdate;
2084         ip += (ip == prefixStart);
2085 
2086         /* Match Loop */
2087         while (ip < ilimit) {
2088                 size_t matchLength = 0;
2089                 size_t offset = 0;
2090                 const BYTE *start = ip + 1;
2091                 U32 curr = (U32)(ip - base);
2092 
2093                 /* check repCode */
2094                 {
2095                         const U32 repIndex = (U32)(curr + 1 - offset_1);
2096                         const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
2097                         const BYTE *const repMatch = repBase + repIndex;
2098                         if (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
2099                                 if (ZSTD_read32(ip + 1) == ZSTD_read32(repMatch)) {
2100                                         /* repcode detected we should take it */
2101                                         const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
2102                                         matchLength =
2103                                             ZSTD_count_2segments(ip + 1 + EQUAL_READ32, repMatch + EQUAL_READ32, iend, repEnd, prefixStart) + EQUAL_READ32;
2104                                         if (depth == 0)
2105                                                 goto _storeSequence;
2106                                 }
2107                 }
2108 
2109                 /* first search (depth 0) */
2110                 {
2111                         size_t offsetFound = 99999999;
2112                         size_t const ml2 = searchMax(ctx, ip, iend, &offsetFound, maxSearches, mls);
2113                         if (ml2 > matchLength)
2114                                 matchLength = ml2, start = ip, offset = offsetFound;
2115                 }
2116 
2117                 if (matchLength < EQUAL_READ32) {
2118                         ip += ((ip - anchor) >> g_searchStrength) + 1; /* jump faster over incompressible sections */
2119                         continue;
2120                 }
2121 
2122                 /* let's try to find a better solution */
2123                 if (depth >= 1)
2124                         while (ip < ilimit) {
2125                                 ip++;
2126                                 curr++;
2127                                 /* check repCode */
2128                                 if (offset) {
2129                                         const U32 repIndex = (U32)(curr - offset_1);
2130                                         const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
2131                                         const BYTE *const repMatch = repBase + repIndex;
2132                                         if (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
2133                                                 if (ZSTD_read32(ip) == ZSTD_read32(repMatch)) {
2134                                                         /* repcode detected */
2135                                                         const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
2136                                                         size_t const repLength =
2137                                                             ZSTD_count_2segments(ip + EQUAL_READ32, repMatch + EQUAL_READ32, iend, repEnd, prefixStart) +
2138                                                             EQUAL_READ32;
2139                                                         int const gain2 = (int)(repLength * 3);
2140                                                         int const gain1 = (int)(matchLength * 3 - ZSTD_highbit32((U32)offset + 1) + 1);
2141                                                         if ((repLength >= EQUAL_READ32) && (gain2 > gain1))
2142                                                                 matchLength = repLength, offset = 0, start = ip;
2143                                                 }
2144                                 }
2145 
2146                                 /* search match, depth 1 */
2147                                 {
2148                                         size_t offset2 = 99999999;
2149                                         size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
2150                                         int const gain2 = (int)(ml2 * 4 - ZSTD_highbit32((U32)offset2 + 1)); /* raw approx */
2151                                         int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 4);
2152                                         if ((ml2 >= EQUAL_READ32) && (gain2 > gain1)) {
2153                                                 matchLength = ml2, offset = offset2, start = ip;
2154                                                 continue; /* search a better one */
2155                                         }
2156                                 }
2157 
2158                                 /* let's find an even better one */
2159                                 if ((depth == 2) && (ip < ilimit)) {
2160                                         ip++;
2161                                         curr++;
2162                                         /* check repCode */
2163                                         if (offset) {
2164                                                 const U32 repIndex = (U32)(curr - offset_1);
2165                                                 const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
2166                                                 const BYTE *const repMatch = repBase + repIndex;
2167                                                 if (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
2168                                                         if (ZSTD_read32(ip) == ZSTD_read32(repMatch)) {
2169                                                                 /* repcode detected */
2170                                                                 const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
2171                                                                 size_t repLength = ZSTD_count_2segments(ip + EQUAL_READ32, repMatch + EQUAL_READ32, iend,
2172                                                                                                         repEnd, prefixStart) +
2173                                                                                    EQUAL_READ32;
2174                                                                 int gain2 = (int)(repLength * 4);
2175                                                                 int gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 1);
2176                                                                 if ((repLength >= EQUAL_READ32) && (gain2 > gain1))
2177                                                                         matchLength = repLength, offset = 0, start = ip;
2178                                                         }
2179                                         }
2180 
2181                                         /* search match, depth 2 */
2182                                         {
2183                                                 size_t offset2 = 99999999;
2184                                                 size_t const ml2 = searchMax(ctx, ip, iend, &offset2, maxSearches, mls);
2185                                                 int const gain2 = (int)(ml2 * 4 - ZSTD_highbit32((U32)offset2 + 1)); /* raw approx */
2186                                                 int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 7);
2187                                                 if ((ml2 >= EQUAL_READ32) && (gain2 > gain1)) {
2188                                                         matchLength = ml2, offset = offset2, start = ip;
2189                                                         continue;
2190                                                 }
2191                                         }
2192                                 }
2193                                 break; /* nothing found : store previous solution */
2194                         }
2195 
2196                 /* catch up */
2197                 if (offset) {
2198                         U32 const matchIndex = (U32)((start - base) - (offset - ZSTD_REP_MOVE));
2199                         const BYTE *match = (matchIndex < dictLimit) ? dictBase + matchIndex : base + matchIndex;
2200                         const BYTE *const mStart = (matchIndex < dictLimit) ? dictStart : prefixStart;
2201                         while ((start > anchor) && (match > mStart) && (start[-1] == match[-1])) {
2202                                 start--;
2203                                 match--;
2204                                 matchLength++;
2205                         } /* catch up */
2206                         offset_2 = offset_1;
2207                         offset_1 = (U32)(offset - ZSTD_REP_MOVE);
2208                 }
2209 
2210         /* store sequence */
2211         _storeSequence : {
2212                 size_t const litLength = start - anchor;
2213                 ZSTD_storeSeq(seqStorePtr, litLength, anchor, (U32)offset, matchLength - MINMATCH);
2214                 anchor = ip = start + matchLength;
2215         }
2216 
2217                 /* check immediate repcode */
2218                 while (ip <= ilimit) {
2219                         const U32 repIndex = (U32)((ip - base) - offset_2);
2220                         const BYTE *const repBase = repIndex < dictLimit ? dictBase : base;
2221                         const BYTE *const repMatch = repBase + repIndex;
2222                         if (((U32)((dictLimit - 1) - repIndex) >= 3) & (repIndex > lowestIndex)) /* intentional overflow */
2223                                 if (ZSTD_read32(ip) == ZSTD_read32(repMatch)) {
2224                                         /* repcode detected we should take it */
2225                                         const BYTE *const repEnd = repIndex < dictLimit ? dictEnd : iend;
2226                                         matchLength =
2227                                             ZSTD_count_2segments(ip + EQUAL_READ32, repMatch + EQUAL_READ32, iend, repEnd, prefixStart) + EQUAL_READ32;
2228                                         offset = offset_2;
2229                                         offset_2 = offset_1;
2230                                         offset_1 = (U32)offset; /* swap offset history */
2231                                         ZSTD_storeSeq(seqStorePtr, 0, anchor, 0, matchLength - MINMATCH);
2232                                         ip += matchLength;
2233                                         anchor = ip;
2234                                         continue; /* faster when present ... (?) */
2235                                 }
2236                         break;
2237                 }
2238         }
2239 
2240         /* Save reps for next block */
2241         ctx->repToConfirm[0] = offset_1;
2242         ctx->repToConfirm[1] = offset_2;
2243 
2244         /* Last Literals */
2245         {
2246                 size_t const lastLLSize = iend - anchor;
2247                 memcpy(seqStorePtr->lit, anchor, lastLLSize);
2248                 seqStorePtr->lit += lastLLSize;
2249         }
2250 }
2251 
2252 void ZSTD_compressBlock_greedy_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize) { ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 0); }
2253 
2254 static void ZSTD_compressBlock_lazy_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
2255 {
2256         ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 1);
2257 }
2258 
2259 static void ZSTD_compressBlock_lazy2_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
2260 {
2261         ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 0, 2);
2262 }
2263 
2264 static void ZSTD_compressBlock_btlazy2_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
2265 {
2266         ZSTD_compressBlock_lazy_extDict_generic(ctx, src, srcSize, 1, 2);
2267 }
2268 
2269 /* The optimal parser */
2270 #include "zstd_opt.h"
2271 
2272 static void ZSTD_compressBlock_btopt(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
2273 {
2274 #ifdef ZSTD_OPT_H_91842398743
2275         ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 0);
2276 #else
2277         (void)ctx;
2278         (void)src;
2279         (void)srcSize;
2280         return;
2281 #endif
2282 }
2283 
2284 static void ZSTD_compressBlock_btopt2(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
2285 {
2286 #ifdef ZSTD_OPT_H_91842398743
2287         ZSTD_compressBlock_opt_generic(ctx, src, srcSize, 1);
2288 #else
2289         (void)ctx;
2290         (void)src;
2291         (void)srcSize;
2292         return;
2293 #endif
2294 }
2295 
2296 static void ZSTD_compressBlock_btopt_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
2297 {
2298 #ifdef ZSTD_OPT_H_91842398743
2299         ZSTD_compressBlock_opt_extDict_generic(ctx, src, srcSize, 0);
2300 #else
2301         (void)ctx;
2302         (void)src;
2303         (void)srcSize;
2304         return;
2305 #endif
2306 }
2307 
2308 static void ZSTD_compressBlock_btopt2_extDict(ZSTD_CCtx *ctx, const void *src, size_t srcSize)
2309 {
2310 #ifdef ZSTD_OPT_H_91842398743
2311         ZSTD_compressBlock_opt_extDict_generic(ctx, src, srcSize, 1);
2312 #else
2313         (void)ctx;
2314         (void)src;
2315         (void)srcSize;
2316         return;
2317 #endif
2318 }
2319 
2320 typedef void (*ZSTD_blockCompressor)(ZSTD_CCtx *ctx, const void *src, size_t srcSize);
2321 
2322 static ZSTD_blockCompressor ZSTD_selectBlockCompressor(ZSTD_strategy strat, int extDict)
2323 {
2324         static const ZSTD_blockCompressor blockCompressor[2][8] = {
2325             {ZSTD_compressBlock_fast, ZSTD_compressBlock_doubleFast, ZSTD_compressBlock_greedy, ZSTD_compressBlock_lazy, ZSTD_compressBlock_lazy2,
2326              ZSTD_compressBlock_btlazy2, ZSTD_compressBlock_btopt, ZSTD_compressBlock_btopt2},
2327             {ZSTD_compressBlock_fast_extDict, ZSTD_compressBlock_doubleFast_extDict, ZSTD_compressBlock_greedy_extDict, ZSTD_compressBlock_lazy_extDict,
2328              ZSTD_compressBlock_lazy2_extDict, ZSTD_compressBlock_btlazy2_extDict, ZSTD_compressBlock_btopt_extDict, ZSTD_compressBlock_btopt2_extDict}};
2329 
2330         return blockCompressor[extDict][(U32)strat];
2331 }
2332 
2333 static size_t ZSTD_compressBlock_internal(ZSTD_CCtx *zc, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
2334 {
2335         ZSTD_blockCompressor const blockCompressor = ZSTD_selectBlockCompressor(zc->params.cParams.strategy, zc->lowLimit < zc->dictLimit);
2336         const BYTE *const base = zc->base;
2337         const BYTE *const istart = (const BYTE *)src;
2338         const U32 curr = (U32)(istart - base);
2339         if (srcSize < MIN_CBLOCK_SIZE + ZSTD_blockHeaderSize + 1)
2340                 return 0; /* don't even attempt compression below a certain srcSize */
2341         ZSTD_resetSeqStore(&(zc->seqStore));
2342         if (curr > zc->nextToUpdate + 384)
2343                 zc->nextToUpdate = curr - MIN(192, (U32)(curr - zc->nextToUpdate - 384)); /* update tree not updated after finding very long rep matches */
2344         blockCompressor(zc, src, srcSize);
2345         return ZSTD_compressSequences(zc, dst, dstCapacity, srcSize);
2346 }
2347 
2348 /*! ZSTD_compress_generic() :
2349 *   Compress a chunk of data into one or multiple blocks.
2350 *   All blocks will be terminated, all input will be consumed.
2351 *   Function will issue an error if there is not enough `dstCapacity` to hold the compressed content.
2352 *   Frame is supposed already started (header already produced)
2353 *   @return : compressed size, or an error code
2354 */
2355 static size_t ZSTD_compress_generic(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, U32 lastFrameChunk)
2356 {
2357         size_t blockSize = cctx->blockSize;
2358         size_t remaining = srcSize;
2359         const BYTE *ip = (const BYTE *)src;
2360         BYTE *const ostart = (BYTE *)dst;
2361         BYTE *op = ostart;
2362         U32 const maxDist = 1 << cctx->params.cParams.windowLog;
2363 
2364         if (cctx->params.fParams.checksumFlag && srcSize)
2365                 xxh64_update(&cctx->xxhState, src, srcSize);
2366 
2367         while (remaining) {
2368                 U32 const lastBlock = lastFrameChunk & (blockSize >= remaining);
2369                 size_t cSize;
2370 
2371                 if (dstCapacity < ZSTD_blockHeaderSize + MIN_CBLOCK_SIZE)
2372                         return ERROR(dstSize_tooSmall); /* not enough space to store compressed block */
2373                 if (remaining < blockSize)
2374                         blockSize = remaining;
2375 
2376                 /* preemptive overflow correction */
2377                 if (cctx->lowLimit > (3U << 29)) {
2378                         U32 const cycleMask = (1 << ZSTD_cycleLog(cctx->params.cParams.hashLog, cctx->params.cParams.strategy)) - 1;
2379                         U32 const curr = (U32)(ip - cctx->base);
2380                         U32 const newCurr = (curr & cycleMask) + (1 << cctx->params.cParams.windowLog);
2381                         U32 const correction = curr - newCurr;
2382                         ZSTD_STATIC_ASSERT(ZSTD_WINDOWLOG_MAX_64 <= 30);
2383                         ZSTD_reduceIndex(cctx, correction);
2384                         cctx->base += correction;
2385                         cctx->dictBase += correction;
2386                         cctx->lowLimit -= correction;
2387                         cctx->dictLimit -= correction;
2388                         if (cctx->nextToUpdate < correction)
2389                                 cctx->nextToUpdate = 0;
2390                         else
2391                                 cctx->nextToUpdate -= correction;
2392                 }
2393 
2394                 if ((U32)(ip + blockSize - cctx->base) > cctx->loadedDictEnd + maxDist) {
2395                         /* enforce maxDist */
2396                         U32 const newLowLimit = (U32)(ip + blockSize - cctx->base) - maxDist;
2397                         if (cctx->lowLimit < newLowLimit)
2398                                 cctx->lowLimit = newLowLimit;
2399                         if (cctx->dictLimit < cctx->lowLimit)
2400                                 cctx->dictLimit = cctx->lowLimit;
2401                 }
2402 
2403                 cSize = ZSTD_compressBlock_internal(cctx, op + ZSTD_blockHeaderSize, dstCapacity - ZSTD_blockHeaderSize, ip, blockSize);
2404                 if (ZSTD_isError(cSize))
2405                         return cSize;
2406 
2407                 if (cSize == 0) { /* block is not compressible */
2408                         U32 const cBlockHeader24 = lastBlock + (((U32)bt_raw) << 1) + (U32)(blockSize << 3);
2409                         if (blockSize + ZSTD_blockHeaderSize > dstCapacity)
2410                                 return ERROR(dstSize_tooSmall);
2411                         ZSTD_writeLE32(op, cBlockHeader24); /* no pb, 4th byte will be overwritten */
2412                         memcpy(op + ZSTD_blockHeaderSize, ip, blockSize);
2413                         cSize = ZSTD_blockHeaderSize + blockSize;
2414                 } else {
2415                         U32 const cBlockHeader24 = lastBlock + (((U32)bt_compressed) << 1) + (U32)(cSize << 3);
2416                         ZSTD_writeLE24(op, cBlockHeader24);
2417                         cSize += ZSTD_blockHeaderSize;
2418                 }
2419 
2420                 remaining -= blockSize;
2421                 dstCapacity -= cSize;
2422                 ip += blockSize;
2423                 op += cSize;
2424         }
2425 
2426         if (lastFrameChunk && (op > ostart))
2427                 cctx->stage = ZSTDcs_ending;
2428         return op - ostart;
2429 }
2430 
2431 static size_t ZSTD_writeFrameHeader(void *dst, size_t dstCapacity, ZSTD_parameters params, U64 pledgedSrcSize, U32 dictID)
2432 {
2433         BYTE *const op = (BYTE *)dst;
2434         U32 const dictIDSizeCode = (dictID > 0) + (dictID >= 256) + (dictID >= 65536); /* 0-3 */
2435         U32 const checksumFlag = params.fParams.checksumFlag > 0;
2436         U32 const windowSize = 1U << params.cParams.windowLog;
2437         U32 const singleSegment = params.fParams.contentSizeFlag && (windowSize >= pledgedSrcSize);
2438         BYTE const windowLogByte = (BYTE)((params.cParams.windowLog - ZSTD_WINDOWLOG_ABSOLUTEMIN) << 3);
2439         U32 const fcsCode =
2440             params.fParams.contentSizeFlag ? (pledgedSrcSize >= 256) + (pledgedSrcSize >= 65536 + 256) + (pledgedSrcSize >= 0xFFFFFFFFU) : 0; /* 0-3 */
2441         BYTE const frameHeaderDecriptionByte = (BYTE)(dictIDSizeCode + (checksumFlag << 2) + (singleSegment << 5) + (fcsCode << 6));
2442         size_t pos;
2443 
2444         if (dstCapacity < ZSTD_frameHeaderSize_max)
2445                 return ERROR(dstSize_tooSmall);
2446 
2447         ZSTD_writeLE32(dst, ZSTD_MAGICNUMBER);
2448         op[4] = frameHeaderDecriptionByte;
2449         pos = 5;
2450         if (!singleSegment)
2451                 op[pos++] = windowLogByte;
2452         switch (dictIDSizeCode) {
2453         default: /* impossible */
2454         case 0: break;
2455         case 1:
2456                 op[pos] = (BYTE)(dictID);
2457                 pos++;
2458                 break;
2459         case 2:
2460                 ZSTD_writeLE16(op + pos, (U16)dictID);
2461                 pos += 2;
2462                 break;
2463         case 3:
2464                 ZSTD_writeLE32(op + pos, dictID);
2465                 pos += 4;
2466                 break;
2467         }
2468         switch (fcsCode) {
2469         default: /* impossible */
2470         case 0:
2471                 if (singleSegment)
2472                         op[pos++] = (BYTE)(pledgedSrcSize);
2473                 break;
2474         case 1:
2475                 ZSTD_writeLE16(op + pos, (U16)(pledgedSrcSize - 256));
2476                 pos += 2;
2477                 break;
2478         case 2:
2479                 ZSTD_writeLE32(op + pos, (U32)(pledgedSrcSize));
2480                 pos += 4;
2481                 break;
2482         case 3:
2483                 ZSTD_writeLE64(op + pos, (U64)(pledgedSrcSize));
2484                 pos += 8;
2485                 break;
2486         }
2487         return pos;
2488 }
2489 
2490 static size_t ZSTD_compressContinue_internal(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, U32 frame, U32 lastFrameChunk)
2491 {
2492         const BYTE *const ip = (const BYTE *)src;
2493         size_t fhSize = 0;
2494 
2495         if (cctx->stage == ZSTDcs_created)
2496                 return ERROR(stage_wrong); /* missing init (ZSTD_compressBegin) */
2497 
2498         if (frame && (cctx->stage == ZSTDcs_init)) {
2499                 fhSize = ZSTD_writeFrameHeader(dst, dstCapacity, cctx->params, cctx->frameContentSize, cctx->dictID);
2500                 if (ZSTD_isError(fhSize))
2501                         return fhSize;
2502                 dstCapacity -= fhSize;
2503                 dst = (char *)dst + fhSize;
2504                 cctx->stage = ZSTDcs_ongoing;
2505         }
2506 
2507         /* Check if blocks follow each other */
2508         if (src != cctx->nextSrc) {
2509                 /* not contiguous */
2510                 ptrdiff_t const delta = cctx->nextSrc - ip;
2511                 cctx->lowLimit = cctx->dictLimit;
2512                 cctx->dictLimit = (U32)(cctx->nextSrc - cctx->base);
2513                 cctx->dictBase = cctx->base;
2514                 cctx->base -= delta;
2515                 cctx->nextToUpdate = cctx->dictLimit;
2516                 if (cctx->dictLimit - cctx->lowLimit < HASH_READ_SIZE)
2517                         cctx->lowLimit = cctx->dictLimit; /* too small extDict */
2518         }
2519 
2520         /* if input and dictionary overlap : reduce dictionary (area presumed modified by input) */
2521         if ((ip + srcSize > cctx->dictBase + cctx->lowLimit) & (ip < cctx->dictBase + cctx->dictLimit)) {
2522                 ptrdiff_t const highInputIdx = (ip + srcSize) - cctx->dictBase;
2523                 U32 const lowLimitMax = (highInputIdx > (ptrdiff_t)cctx->dictLimit) ? cctx->dictLimit : (U32)highInputIdx;
2524                 cctx->lowLimit = lowLimitMax;
2525         }
2526 
2527         cctx->nextSrc = ip + srcSize;
2528 
2529         if (srcSize) {
2530                 size_t const cSize = frame ? ZSTD_compress_generic(cctx, dst, dstCapacity, src, srcSize, lastFrameChunk)
2531                                            : ZSTD_compressBlock_internal(cctx, dst, dstCapacity, src, srcSize);
2532                 if (ZSTD_isError(cSize))
2533                         return cSize;
2534                 return cSize + fhSize;
2535         } else
2536                 return fhSize;
2537 }
2538 
2539 size_t ZSTD_compressContinue(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
2540 {
2541         return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 1, 0);
2542 }
2543 
2544 size_t ZSTD_getBlockSizeMax(ZSTD_CCtx *cctx) { return MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, 1 << cctx->params.cParams.windowLog); }
2545 
2546 size_t ZSTD_compressBlock(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
2547 {
2548         size_t const blockSizeMax = ZSTD_getBlockSizeMax(cctx);
2549         if (srcSize > blockSizeMax)
2550                 return ERROR(srcSize_wrong);
2551         return ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 0, 0);
2552 }
2553 
2554 /*! ZSTD_loadDictionaryContent() :
2555  *  @return : 0, or an error code
2556  */
2557 static size_t ZSTD_loadDictionaryContent(ZSTD_CCtx *zc, const void *src, size_t srcSize)
2558 {
2559         const BYTE *const ip = (const BYTE *)src;
2560         const BYTE *const iend = ip + srcSize;
2561 
2562         /* input becomes curr prefix */
2563         zc->lowLimit = zc->dictLimit;
2564         zc->dictLimit = (U32)(zc->nextSrc - zc->base);
2565         zc->dictBase = zc->base;
2566         zc->base += ip - zc->nextSrc;
2567         zc->nextToUpdate = zc->dictLimit;
2568         zc->loadedDictEnd = zc->forceWindow ? 0 : (U32)(iend - zc->base);
2569 
2570         zc->nextSrc = iend;
2571         if (srcSize <= HASH_READ_SIZE)
2572                 return 0;
2573 
2574         switch (zc->params.cParams.strategy) {
2575         case ZSTD_fast: ZSTD_fillHashTable(zc, iend, zc->params.cParams.searchLength); break;
2576 
2577         case ZSTD_dfast: ZSTD_fillDoubleHashTable(zc, iend, zc->params.cParams.searchLength); break;
2578 
2579         case ZSTD_greedy:
2580         case ZSTD_lazy:
2581         case ZSTD_lazy2:
2582                 if (srcSize >= HASH_READ_SIZE)
2583                         ZSTD_insertAndFindFirstIndex(zc, iend - HASH_READ_SIZE, zc->params.cParams.searchLength);
2584                 break;
2585 
2586         case ZSTD_btlazy2:
2587         case ZSTD_btopt:
2588         case ZSTD_btopt2:
2589                 if (srcSize >= HASH_READ_SIZE)
2590                         ZSTD_updateTree(zc, iend - HASH_READ_SIZE, iend, 1 << zc->params.cParams.searchLog, zc->params.cParams.searchLength);
2591                 break;
2592 
2593         default:
2594                 return ERROR(GENERIC); /* strategy doesn't exist; impossible */
2595         }
2596 
2597         zc->nextToUpdate = (U32)(iend - zc->base);
2598         return 0;
2599 }
2600 
2601 /* Dictionaries that assign zero probability to symbols that show up causes problems
2602    when FSE encoding.  Refuse dictionaries that assign zero probability to symbols
2603    that we may encounter during compression.
2604    NOTE: This behavior is not standard and could be improved in the future. */
2605 static size_t ZSTD_checkDictNCount(short *normalizedCounter, unsigned dictMaxSymbolValue, unsigned maxSymbolValue)
2606 {
2607         U32 s;
2608         if (dictMaxSymbolValue < maxSymbolValue)
2609                 return ERROR(dictionary_corrupted);
2610         for (s = 0; s <= maxSymbolValue; ++s) {
2611                 if (normalizedCounter[s] == 0)
2612                         return ERROR(dictionary_corrupted);
2613         }
2614         return 0;
2615 }
2616 
2617 /* Dictionary format :
2618  * See :
2619  * https://github.com/facebook/zstd/blob/master/doc/zstd_compression_format.md#dictionary-format
2620  */
2621 /*! ZSTD_loadZstdDictionary() :
2622  * @return : 0, or an error code
2623  *  assumptions : magic number supposed already checked
2624  *                dictSize supposed > 8
2625  */
2626 static size_t ZSTD_loadZstdDictionary(ZSTD_CCtx *cctx, const void *dict, size_t dictSize)
2627 {
2628         const BYTE *dictPtr = (const BYTE *)dict;
2629         const BYTE *const dictEnd = dictPtr + dictSize;
2630         short offcodeNCount[MaxOff + 1];
2631         unsigned offcodeMaxValue = MaxOff;
2632 
2633         dictPtr += 4; /* skip magic number */
2634         cctx->dictID = cctx->params.fParams.noDictIDFlag ? 0 : ZSTD_readLE32(dictPtr);
2635         dictPtr += 4;
2636 
2637         {
2638                 size_t const hufHeaderSize = HUF_readCTable_wksp(cctx->hufTable, 255, dictPtr, dictEnd - dictPtr, cctx->tmpCounters, sizeof(cctx->tmpCounters));
2639                 if (HUF_isError(hufHeaderSize))
2640                         return ERROR(dictionary_corrupted);
2641                 dictPtr += hufHeaderSize;
2642         }
2643 
2644         {
2645                 unsigned offcodeLog;
2646                 size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd - dictPtr);
2647                 if (FSE_isError(offcodeHeaderSize))
2648                         return ERROR(dictionary_corrupted);
2649                 if (offcodeLog > OffFSELog)
2650                         return ERROR(dictionary_corrupted);
2651                 /* Defer checking offcodeMaxValue because we need to know the size of the dictionary content */
2652                 CHECK_E(FSE_buildCTable_wksp(cctx->offcodeCTable, offcodeNCount, offcodeMaxValue, offcodeLog, cctx->tmpCounters, sizeof(cctx->tmpCounters)),
2653                         dictionary_corrupted);
2654                 dictPtr += offcodeHeaderSize;
2655         }
2656 
2657         {
2658                 short matchlengthNCount[MaxML + 1];
2659                 unsigned matchlengthMaxValue = MaxML, matchlengthLog;
2660                 size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd - dictPtr);
2661                 if (FSE_isError(matchlengthHeaderSize))
2662                         return ERROR(dictionary_corrupted);
2663                 if (matchlengthLog > MLFSELog)
2664                         return ERROR(dictionary_corrupted);
2665                 /* Every match length code must have non-zero probability */
2666                 CHECK_F(ZSTD_checkDictNCount(matchlengthNCount, matchlengthMaxValue, MaxML));
2667                 CHECK_E(
2668                     FSE_buildCTable_wksp(cctx->matchlengthCTable, matchlengthNCount, matchlengthMaxValue, matchlengthLog, cctx->tmpCounters, sizeof(cctx->tmpCounters)),
2669                     dictionary_corrupted);
2670                 dictPtr += matchlengthHeaderSize;
2671         }
2672 
2673         {
2674                 short litlengthNCount[MaxLL + 1];
2675                 unsigned litlengthMaxValue = MaxLL, litlengthLog;
2676                 size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd - dictPtr);
2677                 if (FSE_isError(litlengthHeaderSize))
2678                         return ERROR(dictionary_corrupted);
2679                 if (litlengthLog > LLFSELog)
2680                         return ERROR(dictionary_corrupted);
2681                 /* Every literal length code must have non-zero probability */
2682                 CHECK_F(ZSTD_checkDictNCount(litlengthNCount, litlengthMaxValue, MaxLL));
2683                 CHECK_E(FSE_buildCTable_wksp(cctx->litlengthCTable, litlengthNCount, litlengthMaxValue, litlengthLog, cctx->tmpCounters, sizeof(cctx->tmpCounters)),
2684                         dictionary_corrupted);
2685                 dictPtr += litlengthHeaderSize;
2686         }
2687 
2688         if (dictPtr + 12 > dictEnd)
2689                 return ERROR(dictionary_corrupted);
2690         cctx->rep[0] = ZSTD_readLE32(dictPtr + 0);
2691         cctx->rep[1] = ZSTD_readLE32(dictPtr + 4);
2692         cctx->rep[2] = ZSTD_readLE32(dictPtr + 8);
2693         dictPtr += 12;
2694 
2695         {
2696                 size_t const dictContentSize = (size_t)(dictEnd - dictPtr);
2697                 U32 offcodeMax = MaxOff;
2698                 if (dictContentSize <= ((U32)-1) - 128 KB) {
2699                         U32 const maxOffset = (U32)dictContentSize + 128 KB; /* The maximum offset that must be supported */
2700                         offcodeMax = ZSTD_highbit32(maxOffset);              /* Calculate minimum offset code required to represent maxOffset */
2701                 }
2702                 /* All offset values <= dictContentSize + 128 KB must be representable */
2703                 CHECK_F(ZSTD_checkDictNCount(offcodeNCount, offcodeMaxValue, MIN(offcodeMax, MaxOff)));
2704                 /* All repCodes must be <= dictContentSize and != 0*/
2705                 {
2706                         U32 u;
2707                         for (u = 0; u < 3; u++) {
2708                                 if (cctx->rep[u] == 0)
2709                                         return ERROR(dictionary_corrupted);
2710                                 if (cctx->rep[u] > dictContentSize)
2711                                         return ERROR(dictionary_corrupted);
2712                         }
2713                 }
2714 
2715                 cctx->flagStaticTables = 1;
2716                 cctx->flagStaticHufTable = HUF_repeat_valid;
2717                 return ZSTD_loadDictionaryContent(cctx, dictPtr, dictContentSize);
2718         }
2719 }
2720 
2721 /** ZSTD_compress_insertDictionary() :
2722 *   @return : 0, or an error code */
2723 static size_t ZSTD_compress_insertDictionary(ZSTD_CCtx *cctx, const void *dict, size_t dictSize)
2724 {
2725         if ((dict == NULL) || (dictSize <= 8))
2726                 return 0;
2727 
2728         /* dict as pure content */
2729         if ((ZSTD_readLE32(dict) != ZSTD_DICT_MAGIC) || (cctx->forceRawDict))
2730                 return ZSTD_loadDictionaryContent(cctx, dict, dictSize);
2731 
2732         /* dict as zstd dictionary */
2733         return ZSTD_loadZstdDictionary(cctx, dict, dictSize);
2734 }
2735 
2736 /*! ZSTD_compressBegin_internal() :
2737 *   @return : 0, or an error code */
2738 static size_t ZSTD_compressBegin_internal(ZSTD_CCtx *cctx, const void *dict, size_t dictSize, ZSTD_parameters params, U64 pledgedSrcSize)
2739 {
2740         ZSTD_compResetPolicy_e const crp = dictSize ? ZSTDcrp_fullReset : ZSTDcrp_continue;
2741         CHECK_F(ZSTD_resetCCtx_advanced(cctx, params, pledgedSrcSize, crp));
2742         return ZSTD_compress_insertDictionary(cctx, dict, dictSize);
2743 }
2744 
2745 /*! ZSTD_compressBegin_advanced() :
2746 *   @return : 0, or an error code */
2747 size_t ZSTD_compressBegin_advanced(ZSTD_CCtx *cctx, const void *dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize)
2748 {
2749         /* compression parameters verification and optimization */
2750         CHECK_F(ZSTD_checkCParams(params.cParams));
2751         return ZSTD_compressBegin_internal(cctx, dict, dictSize, params, pledgedSrcSize);
2752 }
2753 
2754 size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx *cctx, const void *dict, size_t dictSize, int compressionLevel)
2755 {
2756         ZSTD_parameters const params = ZSTD_getParams(compressionLevel, 0, dictSize);
2757         return ZSTD_compressBegin_internal(cctx, dict, dictSize, params, 0);
2758 }
2759 
2760 size_t ZSTD_compressBegin(ZSTD_CCtx *cctx, int compressionLevel) { return ZSTD_compressBegin_usingDict(cctx, NULL, 0, compressionLevel); }
2761 
2762 /*! ZSTD_writeEpilogue() :
2763 *   Ends a frame.
2764 *   @return : nb of bytes written into dst (or an error code) */
2765 static size_t ZSTD_writeEpilogue(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity)
2766 {
2767         BYTE *const ostart = (BYTE *)dst;
2768         BYTE *op = ostart;
2769         size_t fhSize = 0;
2770 
2771         if (cctx->stage == ZSTDcs_created)
2772                 return ERROR(stage_wrong); /* init missing */
2773 
2774         /* special case : empty frame */
2775         if (cctx->stage == ZSTDcs_init) {
2776                 fhSize = ZSTD_writeFrameHeader(dst, dstCapacity, cctx->params, 0, 0);
2777                 if (ZSTD_isError(fhSize))
2778                         return fhSize;
2779                 dstCapacity -= fhSize;
2780                 op += fhSize;
2781                 cctx->stage = ZSTDcs_ongoing;
2782         }
2783 
2784         if (cctx->stage != ZSTDcs_ending) {
2785                 /* write one last empty block, make it the "last" block */
2786                 U32 const cBlockHeader24 = 1 /* last block */ + (((U32)bt_raw) << 1) + 0;
2787                 if (dstCapacity < 4)
2788                         return ERROR(dstSize_tooSmall);
2789                 ZSTD_writeLE32(op, cBlockHeader24);
2790                 op += ZSTD_blockHeaderSize;
2791                 dstCapacity -= ZSTD_blockHeaderSize;
2792         }
2793 
2794         if (cctx->params.fParams.checksumFlag) {
2795                 U32 const checksum = (U32)xxh64_digest(&cctx->xxhState);
2796                 if (dstCapacity < 4)
2797                         return ERROR(dstSize_tooSmall);
2798                 ZSTD_writeLE32(op, checksum);
2799                 op += 4;
2800         }
2801 
2802         cctx->stage = ZSTDcs_created; /* return to "created but no init" status */
2803         return op - ostart;
2804 }
2805 
2806 size_t ZSTD_compressEnd(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
2807 {
2808         size_t endResult;
2809         size_t const cSize = ZSTD_compressContinue_internal(cctx, dst, dstCapacity, src, srcSize, 1, 1);
2810         if (ZSTD_isError(cSize))
2811                 return cSize;
2812         endResult = ZSTD_writeEpilogue(cctx, (char *)dst + cSize, dstCapacity - cSize);
2813         if (ZSTD_isError(endResult))
2814                 return endResult;
2815         return cSize + endResult;
2816 }
2817 
2818 static size_t ZSTD_compress_internal(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize,
2819                                      ZSTD_parameters params)
2820 {
2821         CHECK_F(ZSTD_compressBegin_internal(cctx, dict, dictSize, params, srcSize));
2822         return ZSTD_compressEnd(cctx, dst, dstCapacity, src, srcSize);
2823 }
2824 
2825 size_t ZSTD_compress_usingDict(ZSTD_CCtx *ctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize,
2826                                ZSTD_parameters params)
2827 {
2828         return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, dict, dictSize, params);
2829 }
2830 
2831 size_t ZSTD_compressCCtx(ZSTD_CCtx *ctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, ZSTD_parameters params)
2832 {
2833         return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, NULL, 0, params);
2834 }
2835 
2836 /* =====  Dictionary API  ===== */
2837 
2838 struct ZSTD_CDict_s {
2839         void *dictBuffer;
2840         const void *dictContent;
2841         size_t dictContentSize;
2842         ZSTD_CCtx *refContext;
2843 }; /* typedef'd tp ZSTD_CDict within "zstd.h" */
2844 
2845 size_t ZSTD_CDictWorkspaceBound(ZSTD_compressionParameters cParams) { return ZSTD_CCtxWorkspaceBound(cParams) + ZSTD_ALIGN(sizeof(ZSTD_CDict)); }
2846 
2847 static ZSTD_CDict *ZSTD_createCDict_advanced(const void *dictBuffer, size_t dictSize, unsigned byReference, ZSTD_parameters params, ZSTD_customMem customMem)
2848 {
2849         if (!customMem.customAlloc || !customMem.customFree)
2850                 return NULL;
2851 
2852         {
2853                 ZSTD_CDict *const cdict = (ZSTD_CDict *)ZSTD_malloc(sizeof(ZSTD_CDict), customMem);
2854                 ZSTD_CCtx *const cctx = ZSTD_createCCtx_advanced(customMem);
2855 
2856                 if (!cdict || !cctx) {
2857                         ZSTD_free(cdict, customMem);
2858                         ZSTD_freeCCtx(cctx);
2859                         return NULL;
2860                 }
2861 
2862                 if ((byReference) || (!dictBuffer) || (!dictSize)) {
2863                         cdict->dictBuffer = NULL;
2864                         cdict->dictContent = dictBuffer;
2865                 } else {
2866                         void *const internalBuffer = ZSTD_malloc(dictSize, customMem);
2867                         if (!internalBuffer) {
2868                                 ZSTD_free(cctx, customMem);
2869                                 ZSTD_free(cdict, customMem);
2870                                 return NULL;
2871                         }
2872                         memcpy(internalBuffer, dictBuffer, dictSize);
2873                         cdict->dictBuffer = internalBuffer;
2874                         cdict->dictContent = internalBuffer;
2875                 }
2876 
2877                 {
2878                         size_t const errorCode = ZSTD_compressBegin_advanced(cctx, cdict->dictContent, dictSize, params, 0);
2879                         if (ZSTD_isError(errorCode)) {
2880                                 ZSTD_free(cdict->dictBuffer, customMem);
2881                                 ZSTD_free(cdict, customMem);
2882                                 ZSTD_freeCCtx(cctx);
2883                                 return NULL;
2884                         }
2885                 }
2886 
2887                 cdict->refContext = cctx;
2888                 cdict->dictContentSize = dictSize;
2889                 return cdict;
2890         }
2891 }
2892 
2893 ZSTD_CDict *ZSTD_initCDict(const void *dict, size_t dictSize, ZSTD_parameters params, void *workspace, size_t workspaceSize)
2894 {
2895         ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
2896         return ZSTD_createCDict_advanced(dict, dictSize, 1, params, stackMem);
2897 }
2898 
2899 size_t ZSTD_freeCDict(ZSTD_CDict *cdict)
2900 {
2901         if (cdict == NULL)
2902                 return 0; /* support free on NULL */
2903         {
2904                 ZSTD_customMem const cMem = cdict->refContext->customMem;
2905                 ZSTD_freeCCtx(cdict->refContext);
2906                 ZSTD_free(cdict->dictBuffer, cMem);
2907                 ZSTD_free(cdict, cMem);
2908                 return 0;
2909         }
2910 }
2911 
2912 static ZSTD_parameters ZSTD_getParamsFromCDict(const ZSTD_CDict *cdict) { return ZSTD_getParamsFromCCtx(cdict->refContext); }
2913 
2914 size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx *cctx, const ZSTD_CDict *cdict, unsigned long long pledgedSrcSize)
2915 {
2916         if (cdict->dictContentSize)
2917                 CHECK_F(ZSTD_copyCCtx(cctx, cdict->refContext, pledgedSrcSize))
2918         else {
2919                 ZSTD_parameters params = cdict->refContext->params;
2920                 params.fParams.contentSizeFlag = (pledgedSrcSize > 0);
2921                 CHECK_F(ZSTD_compressBegin_advanced(cctx, NULL, 0, params, pledgedSrcSize));
2922         }
2923         return 0;
2924 }
2925 
2926 /*! ZSTD_compress_usingCDict() :
2927 *   Compression using a digested Dictionary.
2928 *   Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.
2929 *   Note that compression level is decided during dictionary creation */
2930 size_t ZSTD_compress_usingCDict(ZSTD_CCtx *cctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const ZSTD_CDict *cdict)
2931 {
2932         CHECK_F(ZSTD_compressBegin_usingCDict(cctx, cdict, srcSize));
2933 
2934         if (cdict->refContext->params.fParams.contentSizeFlag == 1) {
2935                 cctx->params.fParams.contentSizeFlag = 1;
2936                 cctx->frameContentSize = srcSize;
2937         } else {
2938                 cctx->params.fParams.contentSizeFlag = 0;
2939         }
2940 
2941         return ZSTD_compressEnd(cctx, dst, dstCapacity, src, srcSize);
2942 }
2943 
2944 /* ******************************************************************
2945 *  Streaming
2946 ********************************************************************/
2947 
2948 typedef enum { zcss_init, zcss_load, zcss_flush, zcss_final } ZSTD_cStreamStage;
2949 
2950 struct ZSTD_CStream_s {
2951         ZSTD_CCtx *cctx;
2952         ZSTD_CDict *cdictLocal;
2953         const ZSTD_CDict *cdict;
2954         char *inBuff;
2955         size_t inBuffSize;
2956         size_t inToCompress;
2957         size_t inBuffPos;
2958         size_t inBuffTarget;
2959         size_t blockSize;
2960         char *outBuff;
2961         size_t outBuffSize;
2962         size_t outBuffContentSize;
2963         size_t outBuffFlushedSize;
2964         ZSTD_cStreamStage stage;
2965         U32 checksum;
2966         U32 frameEnded;
2967         U64 pledgedSrcSize;
2968         U64 inputProcessed;
2969         ZSTD_parameters params;
2970         ZSTD_customMem customMem;
2971 }; /* typedef'd to ZSTD_CStream within "zstd.h" */
2972 
2973 size_t ZSTD_CStreamWorkspaceBound(ZSTD_compressionParameters cParams)
2974 {
2975         size_t const inBuffSize = (size_t)1 << cParams.windowLog;
2976         size_t const blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, inBuffSize);
2977         size_t const outBuffSize = ZSTD_compressBound(blockSize) + 1;
2978 
2979         return ZSTD_CCtxWorkspaceBound(cParams) + ZSTD_ALIGN(sizeof(ZSTD_CStream)) + ZSTD_ALIGN(inBuffSize) + ZSTD_ALIGN(outBuffSize);
2980 }
2981 
2982 ZSTD_CStream *ZSTD_createCStream_advanced(ZSTD_customMem customMem)
2983 {
2984         ZSTD_CStream *zcs;
2985 
2986         if (!customMem.customAlloc || !customMem.customFree)
2987                 return NULL;
2988 
2989         zcs = (ZSTD_CStream *)ZSTD_malloc(sizeof(ZSTD_CStream), customMem);
2990         if (zcs == NULL)
2991                 return NULL;
2992         memset(zcs, 0, sizeof(ZSTD_CStream));
2993         memcpy(&zcs->customMem, &customMem, sizeof(ZSTD_customMem));
2994         zcs->cctx = ZSTD_createCCtx_advanced(customMem);
2995         if (zcs->cctx == NULL) {
2996                 ZSTD_freeCStream(zcs);
2997                 return NULL;
2998         }
2999         return zcs;
3000 }
3001 
3002 size_t ZSTD_freeCStream(ZSTD_CStream *zcs)
3003 {
3004         if (zcs == NULL)
3005                 return 0; /* support free on NULL */
3006         {
3007                 ZSTD_customMem const cMem = zcs->customMem;
3008                 ZSTD_freeCCtx(zcs->cctx);
3009                 zcs->cctx = NULL;
3010                 ZSTD_freeCDict(zcs->cdictLocal);
3011                 zcs->cdictLocal = NULL;
3012                 ZSTD_free(zcs->inBuff, cMem);
3013                 zcs->inBuff = NULL;
3014                 ZSTD_free(zcs->outBuff, cMem);
3015                 zcs->outBuff = NULL;
3016                 ZSTD_free(zcs, cMem);
3017                 return 0;
3018         }
3019 }
3020 
3021 /*======   Initialization   ======*/
3022 
3023 size_t ZSTD_CStreamInSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX; }
3024 size_t ZSTD_CStreamOutSize(void) { return ZSTD_compressBound(ZSTD_BLOCKSIZE_ABSOLUTEMAX) + ZSTD_blockHeaderSize + 4 /* 32-bits hash */; }
3025 
3026 static size_t ZSTD_resetCStream_internal(ZSTD_CStream *zcs, unsigned long long pledgedSrcSize)
3027 {
3028         if (zcs->inBuffSize == 0)
3029                 return ERROR(stage_wrong); /* zcs has not been init at least once => can't reset */
3030 
3031         if (zcs->cdict)
3032                 CHECK_F(ZSTD_compressBegin_usingCDict(zcs->cctx, zcs->cdict, pledgedSrcSize))
3033         else
3034                 CHECK_F(ZSTD_compressBegin_advanced(zcs->cctx, NULL, 0, zcs->params, pledgedSrcSize));
3035 
3036         zcs->inToCompress = 0;
3037         zcs->inBuffPos = 0;
3038         zcs->inBuffTarget = zcs->blockSize;
3039         zcs->outBuffContentSize = zcs->outBuffFlushedSize = 0;
3040         zcs->stage = zcss_load;
3041         zcs->frameEnded = 0;
3042         zcs->pledgedSrcSize = pledgedSrcSize;
3043         zcs->inputProcessed = 0;
3044         return 0; /* ready to go */
3045 }
3046 
3047 size_t ZSTD_resetCStream(ZSTD_CStream *zcs, unsigned long long pledgedSrcSize)
3048 {
3049 
3050         zcs->params.fParams.contentSizeFlag = (pledgedSrcSize > 0);
3051 
3052         return ZSTD_resetCStream_internal(zcs, pledgedSrcSize);
3053 }
3054 
3055 static size_t ZSTD_initCStream_advanced(ZSTD_CStream *zcs, const void *dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize)
3056 {
3057         /* allocate buffers */
3058         {
3059                 size_t const neededInBuffSize = (size_t)1 << params.cParams.windowLog;
3060                 if (zcs->inBuffSize < neededInBuffSize) {
3061                         zcs->inBuffSize = neededInBuffSize;
3062                         ZSTD_free(zcs->inBuff, zcs->customMem);
3063                         zcs->inBuff = (char *)ZSTD_malloc(neededInBuffSize, zcs->customMem);
3064                         if (zcs->inBuff == NULL)
3065                                 return ERROR(memory_allocation);
3066                 }
3067                 zcs->blockSize = MIN(ZSTD_BLOCKSIZE_ABSOLUTEMAX, neededInBuffSize);
3068         }
3069         if (zcs->outBuffSize < ZSTD_compressBound(zcs->blockSize) + 1) {
3070                 zcs->outBuffSize = ZSTD_compressBound(zcs->blockSize) + 1;
3071                 ZSTD_free(zcs->outBuff, zcs->customMem);
3072                 zcs->outBuff = (char *)ZSTD_malloc(zcs->outBuffSize, zcs->customMem);
3073                 if (zcs->outBuff == NULL)
3074                         return ERROR(memory_allocation);
3075         }
3076 
3077         if (dict && dictSize >= 8) {
3078                 ZSTD_freeCDict(zcs->cdictLocal);
3079                 zcs->cdictLocal = ZSTD_createCDict_advanced(dict, dictSize, 0, params, zcs->customMem);
3080                 if (zcs->cdictLocal == NULL)
3081                         return ERROR(memory_allocation);
3082                 zcs->cdict = zcs->cdictLocal;
3083         } else
3084                 zcs->cdict = NULL;
3085 
3086         zcs->checksum = params.fParams.checksumFlag > 0;
3087         zcs->params = params;
3088 
3089         return ZSTD_resetCStream_internal(zcs, pledgedSrcSize);
3090 }
3091 
3092 ZSTD_CStream *ZSTD_initCStream(ZSTD_parameters params, unsigned long long pledgedSrcSize, void *workspace, size_t workspaceSize)
3093 {
3094         ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
3095         ZSTD_CStream *const zcs = ZSTD_createCStream_advanced(stackMem);
3096         if (zcs) {
3097                 size_t const code = ZSTD_initCStream_advanced(zcs, NULL, 0, params, pledgedSrcSize);
3098                 if (ZSTD_isError(code)) {
3099                         return NULL;
3100                 }
3101         }
3102         return zcs;
3103 }
3104 
3105 ZSTD_CStream *ZSTD_initCStream_usingCDict(const ZSTD_CDict *cdict, unsigned long long pledgedSrcSize, void *workspace, size_t workspaceSize)
3106 {
3107         ZSTD_parameters const params = ZSTD_getParamsFromCDict(cdict);
3108         ZSTD_CStream *const zcs = ZSTD_initCStream(params, pledgedSrcSize, workspace, workspaceSize);
3109         if (zcs) {
3110                 zcs->cdict = cdict;
3111                 if (ZSTD_isError(ZSTD_resetCStream_internal(zcs, pledgedSrcSize))) {
3112                         return NULL;
3113                 }
3114         }
3115         return zcs;
3116 }
3117 
3118 /*======   Compression   ======*/
3119 
3120 typedef enum { zsf_gather, zsf_flush, zsf_end } ZSTD_flush_e;
3121 
3122 ZSTD_STATIC size_t ZSTD_limitCopy(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
3123 {
3124         size_t const length = MIN(dstCapacity, srcSize);
3125         memcpy(dst, src, length);
3126         return length;
3127 }
3128 
3129 static size_t ZSTD_compressStream_generic(ZSTD_CStream *zcs, void *dst, size_t *dstCapacityPtr, const void *src, size_t *srcSizePtr, ZSTD_flush_e const flush)
3130 {
3131         U32 someMoreWork = 1;
3132         const char *const istart = (const char *)src;
3133         const char *const iend = istart + *srcSizePtr;
3134         const char *ip = istart;
3135         char *const ostart = (char *)dst;
3136         char *const oend = ostart + *dstCapacityPtr;
3137         char *op = ostart;
3138 
3139         while (someMoreWork) {
3140                 switch (zcs->stage) {
3141                 case zcss_init:
3142                         return ERROR(init_missing); /* call ZBUFF_compressInit() first ! */
3143 
3144                 case zcss_load:
3145                         /* complete inBuffer */
3146                         {
3147                                 size_t const toLoad = zcs->inBuffTarget - zcs->inBuffPos;
3148                                 size_t const loaded = ZSTD_limitCopy(zcs->inBuff + zcs->inBuffPos, toLoad, ip, iend - ip);
3149                                 zcs->inBuffPos += loaded;
3150                                 ip += loaded;
3151                                 if ((zcs->inBuffPos == zcs->inToCompress) || (!flush && (toLoad != loaded))) {
3152                                         someMoreWork = 0;
3153                                         break; /* not enough input to get a full block : stop there, wait for more */
3154                                 }
3155                         }
3156                         /* compress curr block (note : this stage cannot be stopped in the middle) */
3157                         {
3158                                 void *cDst;
3159                                 size_t cSize;
3160                                 size_t const iSize = zcs->inBuffPos - zcs->inToCompress;
3161                                 size_t oSize = oend - op;
3162                                 if (oSize >= ZSTD_compressBound(iSize))
3163                                         cDst = op; /* compress directly into output buffer (avoid flush stage) */
3164                                 else
3165                                         cDst = zcs->outBuff, oSize = zcs->outBuffSize;
3166                                 cSize = (flush == zsf_end) ? ZSTD_compressEnd(zcs->cctx, cDst, oSize, zcs->inBuff + zcs->inToCompress, iSize)
3167                                                            : ZSTD_compressContinue(zcs->cctx, cDst, oSize, zcs->inBuff + zcs->inToCompress, iSize);
3168                                 if (ZSTD_isError(cSize))
3169                                         return cSize;
3170                                 if (flush == zsf_end)
3171                                         zcs->frameEnded = 1;
3172                                 /* prepare next block */
3173                                 zcs->inBuffTarget = zcs->inBuffPos + zcs->blockSize;
3174                                 if (zcs->inBuffTarget > zcs->inBuffSize)
3175                                         zcs->inBuffPos = 0, zcs->inBuffTarget = zcs->blockSize; /* note : inBuffSize >= blockSize */
3176                                 zcs->inToCompress = zcs->inBuffPos;
3177                                 if (cDst == op) {
3178                                         op += cSize;
3179                                         break;
3180                                 } /* no need to flush */
3181                                 zcs->outBuffContentSize = cSize;
3182                                 zcs->outBuffFlushedSize = 0;
3183                                 zcs->stage = zcss_flush; /* pass-through to flush stage */
3184                         }
3185                         /* fall through */
3186 
3187                 case zcss_flush: {
3188                         size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
3189                         size_t const flushed = ZSTD_limitCopy(op, oend - op, zcs->outBuff + zcs->outBuffFlushedSize, toFlush);
3190                         op += flushed;
3191                         zcs->outBuffFlushedSize += flushed;
3192                         if (toFlush != flushed) {
3193                                 someMoreWork = 0;
3194                                 break;
3195                         } /* dst too small to store flushed data : stop there */
3196                         zcs->outBuffContentSize = zcs->outBuffFlushedSize = 0;
3197                         zcs->stage = zcss_load;
3198                         break;
3199                 }
3200 
3201                 case zcss_final:
3202                         someMoreWork = 0; /* do nothing */
3203                         break;
3204 
3205                 default:
3206                         return ERROR(GENERIC); /* impossible */
3207                 }
3208         }
3209 
3210         *srcSizePtr = ip - istart;
3211         *dstCapacityPtr = op - ostart;
3212         zcs->inputProcessed += *srcSizePtr;
3213         if (zcs->frameEnded)
3214                 return 0;
3215         {
3216                 size_t hintInSize = zcs->inBuffTarget - zcs->inBuffPos;
3217                 if (hintInSize == 0)
3218                         hintInSize = zcs->blockSize;
3219                 return hintInSize;
3220         }
3221 }
3222 
3223 size_t ZSTD_compressStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output, ZSTD_inBuffer *input)
3224 {
3225         size_t sizeRead = input->size - input->pos;
3226         size_t sizeWritten = output->size - output->pos;
3227         size_t const result =
3228             ZSTD_compressStream_generic(zcs, (char *)(output->dst) + output->pos, &sizeWritten, (const char *)(input->src) + input->pos, &sizeRead, zsf_gather);
3229         input->pos += sizeRead;
3230         output->pos += sizeWritten;
3231         return result;
3232 }
3233 
3234 /*======   Finalize   ======*/
3235 
3236 /*! ZSTD_flushStream() :
3237 *   @return : amount of data remaining to flush */
3238 size_t ZSTD_flushStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output)
3239 {
3240         size_t srcSize = 0;
3241         size_t sizeWritten = output->size - output->pos;
3242         size_t const result = ZSTD_compressStream_generic(zcs, (char *)(output->dst) + output->pos, &sizeWritten, &srcSize,
3243                                                           &srcSize, /* use a valid src address instead of NULL */
3244                                                           zsf_flush);
3245         output->pos += sizeWritten;
3246         if (ZSTD_isError(result))
3247                 return result;
3248         return zcs->outBuffContentSize - zcs->outBuffFlushedSize; /* remaining to flush */
3249 }
3250 
3251 size_t ZSTD_endStream(ZSTD_CStream *zcs, ZSTD_outBuffer *output)
3252 {
3253         BYTE *const ostart = (BYTE *)(output->dst) + output->pos;
3254         BYTE *const oend = (BYTE *)(output->dst) + output->size;
3255         BYTE *op = ostart;
3256 
3257         if ((zcs->pledgedSrcSize) && (zcs->inputProcessed != zcs->pledgedSrcSize))
3258                 return ERROR(srcSize_wrong); /* pledgedSrcSize not respected */
3259 
3260         if (zcs->stage != zcss_final) {
3261                 /* flush whatever remains */
3262                 size_t srcSize = 0;
3263                 size_t sizeWritten = output->size - output->pos;
3264                 size_t const notEnded =
3265                     ZSTD_compressStream_generic(zcs, ostart, &sizeWritten, &srcSize, &srcSize, zsf_end); /* use a valid src address instead of NULL */
3266                 size_t const remainingToFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
3267                 op += sizeWritten;
3268                 if (remainingToFlush) {
3269                         output->pos += sizeWritten;
3270                         return remainingToFlush + ZSTD_BLOCKHEADERSIZE /* final empty block */ + (zcs->checksum * 4);
3271                 }
3272                 /* create epilogue */
3273                 zcs->stage = zcss_final;
3274                 zcs->outBuffContentSize = !notEnded ? 0 : ZSTD_compressEnd(zcs->cctx, zcs->outBuff, zcs->outBuffSize, NULL,
3275                                                                            0); /* write epilogue, including final empty block, into outBuff */
3276         }
3277 
3278         /* flush epilogue */
3279         {
3280                 size_t const toFlush = zcs->outBuffContentSize - zcs->outBuffFlushedSize;
3281                 size_t const flushed = ZSTD_limitCopy(op, oend - op, zcs->outBuff + zcs->outBuffFlushedSize, toFlush);
3282                 op += flushed;
3283                 zcs->outBuffFlushedSize += flushed;
3284                 output->pos += op - ostart;
3285                 if (toFlush == flushed)
3286                         zcs->stage = zcss_init; /* end reached */
3287                 return toFlush - flushed;
3288         }
3289 }
3290 
3291 /*-=====  Pre-defined compression levels  =====-*/
3292 
3293 #define ZSTD_DEFAULT_CLEVEL 1
3294 #define ZSTD_MAX_CLEVEL 22
3295 int ZSTD_maxCLevel(void) { return ZSTD_MAX_CLEVEL; }
3296 
3297 static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEVEL + 1] = {
3298     {
3299         /* "default" */
3300         /* W,  C,  H,  S,  L, TL, strat */
3301         {18, 12, 12, 1, 7, 16, ZSTD_fast},    /* level  0 - never used */
3302         {19, 13, 14, 1, 7, 16, ZSTD_fast},    /* level  1 */
3303         {19, 15, 16, 1, 6, 16, ZSTD_fast},    /* level  2 */
3304         {20, 16, 17, 1, 5, 16, ZSTD_dfast},   /* level  3.*/
3305         {20, 18, 18, 1, 5, 16, ZSTD_dfast},   /* level  4.*/
3306         {20, 15, 18, 3, 5, 16, ZSTD_greedy},  /* level  5 */
3307         {21, 16, 19, 2, 5, 16, ZSTD_lazy},    /* level  6 */
3308         {21, 17, 20, 3, 5, 16, ZSTD_lazy},    /* level  7 */
3309         {21, 18, 20, 3, 5, 16, ZSTD_lazy2},   /* level  8 */
3310         {21, 20, 20, 3, 5, 16, ZSTD_lazy2},   /* level  9 */
3311         {21, 19, 21, 4, 5, 16, ZSTD_lazy2},   /* level 10 */
3312         {22, 20, 22, 4, 5, 16, ZSTD_lazy2},   /* level 11 */
3313         {22, 20, 22, 5, 5, 16, ZSTD_lazy2},   /* level 12 */
3314         {22, 21, 22, 5, 5, 16, ZSTD_lazy2},   /* level 13 */
3315         {22, 21, 22, 6, 5, 16, ZSTD_lazy2},   /* level 14 */
3316         {22, 21, 21, 5, 5, 16, ZSTD_btlazy2}, /* level 15 */
3317         {23, 22, 22, 5, 5, 16, ZSTD_btlazy2}, /* level 16 */
3318         {23, 21, 22, 4, 5, 24, ZSTD_btopt},   /* level 17 */
3319         {23, 23, 22, 6, 5, 32, ZSTD_btopt},   /* level 18 */
3320         {23, 23, 22, 6, 3, 48, ZSTD_btopt},   /* level 19 */
3321         {25, 25, 23, 7, 3, 64, ZSTD_btopt2},  /* level 20 */
3322         {26, 26, 23, 7, 3, 256, ZSTD_btopt2}, /* level 21 */
3323         {27, 27, 25, 9, 3, 512, ZSTD_btopt2}, /* level 22 */
3324     },
3325     {
3326         /* for srcSize <= 256 KB */
3327         /* W,  C,  H,  S,  L,  T, strat */
3328         {0, 0, 0, 0, 0, 0, ZSTD_fast},   /* level  0 - not used */
3329         {18, 13, 14, 1, 6, 8, ZSTD_fast},      /* level  1 */
3330         {18, 14, 13, 1, 5, 8, ZSTD_dfast},     /* level  2 */
3331         {18, 16, 15, 1, 5, 8, ZSTD_dfast},     /* level  3 */
3332         {18, 15, 17, 1, 5, 8, ZSTD_greedy},    /* level  4.*/
3333         {18, 16, 17, 4, 5, 8, ZSTD_greedy},    /* level  5.*/
3334         {18, 16, 17, 3, 5, 8, ZSTD_lazy},      /* level  6.*/
3335         {18, 17, 17, 4, 4, 8, ZSTD_lazy},      /* level  7 */
3336         {18, 17, 17, 4, 4, 8, ZSTD_lazy2},     /* level  8 */
3337         {18, 17, 17, 5, 4, 8, ZSTD_lazy2},     /* level  9 */
3338         {18, 17, 17, 6, 4, 8, ZSTD_lazy2},     /* level 10 */
3339         {18, 18, 17, 6, 4, 8, ZSTD_lazy2},     /* level 11.*/
3340         {18, 18, 17, 7, 4, 8, ZSTD_lazy2},     /* level 12.*/
3341         {18, 19, 17, 6, 4, 8, ZSTD_btlazy2},   /* level 13 */
3342         {18, 18, 18, 4, 4, 16, ZSTD_btopt},    /* level 14.*/
3343         {18, 18, 18, 4, 3, 16, ZSTD_btopt},    /* level 15.*/
3344         {18, 19, 18, 6, 3, 32, ZSTD_btopt},    /* level 16.*/
3345         {18, 19, 18, 8, 3, 64, ZSTD_btopt},    /* level 17.*/
3346         {18, 19, 18, 9, 3, 128, ZSTD_btopt},   /* level 18.*/
3347         {18, 19, 18, 10, 3, 256, ZSTD_btopt},  /* level 19.*/
3348         {18, 19, 18, 11, 3, 512, ZSTD_btopt2}, /* level 20.*/
3349         {18, 19, 18, 12, 3, 512, ZSTD_btopt2}, /* level 21.*/
3350         {18, 19, 18, 13, 3, 512, ZSTD_btopt2}, /* level 22.*/
3351     },
3352     {
3353         /* for srcSize <= 128 KB */
3354         /* W,  C,  H,  S,  L,  T, strat */
3355         {17, 12, 12, 1, 7, 8, ZSTD_fast},      /* level  0 - not used */
3356         {17, 12, 13, 1, 6, 8, ZSTD_fast},      /* level  1 */
3357         {17, 13, 16, 1, 5, 8, ZSTD_fast},      /* level  2 */
3358         {17, 16, 16, 2, 5, 8, ZSTD_dfast},     /* level  3 */
3359         {17, 13, 15, 3, 4, 8, ZSTD_greedy},    /* level  4 */
3360         {17, 15, 17, 4, 4, 8, ZSTD_greedy},    /* level  5 */
3361         {17, 16, 17, 3, 4, 8, ZSTD_lazy},      /* level  6 */
3362         {17, 15, 17, 4, 4, 8, ZSTD_lazy2},     /* level  7 */
3363         {17, 17, 17, 4, 4, 8, ZSTD_lazy2},     /* level  8 */
3364         {17, 17, 17, 5, 4, 8, ZSTD_lazy2},     /* level  9 */
3365         {17, 17, 17, 6, 4, 8, ZSTD_lazy2},     /* level 10 */
3366         {17, 17, 17, 7, 4, 8, ZSTD_lazy2},     /* level 11 */
3367         {17, 17, 17, 8, 4, 8, ZSTD_lazy2},     /* level 12 */
3368         {17, 18, 17, 6, 4, 8, ZSTD_btlazy2},   /* level 13.*/
3369         {17, 17, 17, 7, 3, 8, ZSTD_btopt},     /* level 14.*/
3370         {17, 17, 17, 7, 3, 16, ZSTD_btopt},    /* level 15.*/
3371         {17, 18, 17, 7, 3, 32, ZSTD_btopt},    /* level 16.*/
3372         {17, 18, 17, 7, 3, 64, ZSTD_btopt},    /* level 17.*/
3373         {17, 18, 17, 7, 3, 256, ZSTD_btopt},   /* level 18.*/
3374         {17, 18, 17, 8, 3, 256, ZSTD_btopt},   /* level 19.*/
3375         {17, 18, 17, 9, 3, 256, ZSTD_btopt2},  /* level 20.*/
3376         {17, 18, 17, 10, 3, 256, ZSTD_btopt2}, /* level 21.*/
3377         {17, 18, 17, 11, 3, 512, ZSTD_btopt2}, /* level 22.*/
3378     },
3379     {
3380         /* for srcSize <= 16 KB */
3381         /* W,  C,  H,  S,  L,  T, strat */
3382         {14, 12, 12, 1, 7, 6, ZSTD_fast},      /* level  0 - not used */
3383         {14, 14, 14, 1, 6, 6, ZSTD_fast},      /* level  1 */
3384         {14, 14, 14, 1, 4, 6, ZSTD_fast},      /* level  2 */
3385         {14, 14, 14, 1, 4, 6, ZSTD_dfast},     /* level  3.*/
3386         {14, 14, 14, 4, 4, 6, ZSTD_greedy},    /* level  4.*/
3387         {14, 14, 14, 3, 4, 6, ZSTD_lazy},      /* level  5.*/
3388         {14, 14, 14, 4, 4, 6, ZSTD_lazy2},     /* level  6 */
3389         {14, 14, 14, 5, 4, 6, ZSTD_lazy2},     /* level  7 */
3390         {14, 14, 14, 6, 4, 6, ZSTD_lazy2},     /* level  8.*/
3391         {14, 15, 14, 6, 4, 6, ZSTD_btlazy2},   /* level  9.*/
3392         {14, 15, 14, 3, 3, 6, ZSTD_btopt},     /* level 10.*/
3393         {14, 15, 14, 6, 3, 8, ZSTD_btopt},     /* level 11.*/
3394         {14, 15, 14, 6, 3, 16, ZSTD_btopt},    /* level 12.*/
3395         {14, 15, 14, 6, 3, 24, ZSTD_btopt},    /* level 13.*/
3396         {14, 15, 15, 6, 3, 48, ZSTD_btopt},    /* level 14.*/
3397         {14, 15, 15, 6, 3, 64, ZSTD_btopt},    /* level 15.*/
3398         {14, 15, 15, 6, 3, 96, ZSTD_btopt},    /* level 16.*/
3399         {14, 15, 15, 6, 3, 128, ZSTD_btopt},   /* level 17.*/
3400         {14, 15, 15, 6, 3, 256, ZSTD_btopt},   /* level 18.*/
3401         {14, 15, 15, 7, 3, 256, ZSTD_btopt},   /* level 19.*/
3402         {14, 15, 15, 8, 3, 256, ZSTD_btopt2},  /* level 20.*/
3403         {14, 15, 15, 9, 3, 256, ZSTD_btopt2},  /* level 21.*/
3404         {14, 15, 15, 10, 3, 256, ZSTD_btopt2}, /* level 22.*/
3405     },
3406 };
3407 
3408 /*! ZSTD_getCParams() :
3409 *   @return ZSTD_compressionParameters structure for a selected compression level, `srcSize` and `dictSize`.
3410 *   Size values are optional, provide 0 if not known or unused */
3411 ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long srcSize, size_t dictSize)
3412 {
3413         ZSTD_compressionParameters cp;
3414         size_t const addedSize = srcSize ? 0 : 500;
3415         U64 const rSize = srcSize + dictSize ? srcSize + dictSize + addedSize : (U64)-1;
3416         U32 const tableID = (rSize <= 256 KB) + (rSize <= 128 KB) + (rSize <= 16 KB); /* intentional underflow for srcSizeHint == 0 */
3417         if (compressionLevel <= 0)
3418                 compressionLevel = ZSTD_DEFAULT_CLEVEL; /* 0 == default; no negative compressionLevel yet */
3419         if (compressionLevel > ZSTD_MAX_CLEVEL)
3420                 compressionLevel = ZSTD_MAX_CLEVEL;
3421         cp = ZSTD_defaultCParameters[tableID][compressionLevel];
3422         if (ZSTD_32bits()) { /* auto-correction, for 32-bits mode */
3423                 if (cp.windowLog > ZSTD_WINDOWLOG_MAX)
3424                         cp.windowLog = ZSTD_WINDOWLOG_MAX;
3425                 if (cp.chainLog > ZSTD_CHAINLOG_MAX)
3426                         cp.chainLog = ZSTD_CHAINLOG_MAX;
3427                 if (cp.hashLog > ZSTD_HASHLOG_MAX)
3428                         cp.hashLog = ZSTD_HASHLOG_MAX;
3429         }
3430         cp = ZSTD_adjustCParams(cp, srcSize, dictSize);
3431         return cp;
3432 }
3433 
3434 /*! ZSTD_getParams() :
3435 *   same as ZSTD_getCParams(), but @return a `ZSTD_parameters` object (instead of `ZSTD_compressionParameters`).
3436 *   All fields of `ZSTD_frameParameters` are set to default (0) */
3437 ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long srcSize, size_t dictSize)
3438 {
3439         ZSTD_parameters params;
3440         ZSTD_compressionParameters const cParams = ZSTD_getCParams(compressionLevel, srcSize, dictSize);
3441         memset(&params, 0, sizeof(params));
3442         params.cParams = cParams;
3443         return params;
3444 }
3445 
3446 EXPORT_SYMBOL(ZSTD_maxCLevel);
3447 EXPORT_SYMBOL(ZSTD_compressBound);
3448 
3449 EXPORT_SYMBOL(ZSTD_CCtxWorkspaceBound);
3450 EXPORT_SYMBOL(ZSTD_initCCtx);
3451 EXPORT_SYMBOL(ZSTD_compressCCtx);
3452 EXPORT_SYMBOL(ZSTD_compress_usingDict);
3453 
3454 EXPORT_SYMBOL(ZSTD_CDictWorkspaceBound);
3455 EXPORT_SYMBOL(ZSTD_initCDict);
3456 EXPORT_SYMBOL(ZSTD_compress_usingCDict);
3457 
3458 EXPORT_SYMBOL(ZSTD_CStreamWorkspaceBound);
3459 EXPORT_SYMBOL(ZSTD_initCStream);
3460 EXPORT_SYMBOL(ZSTD_initCStream_usingCDict);
3461 EXPORT_SYMBOL(ZSTD_resetCStream);
3462 EXPORT_SYMBOL(ZSTD_compressStream);
3463 EXPORT_SYMBOL(ZSTD_flushStream);
3464 EXPORT_SYMBOL(ZSTD_endStream);
3465 EXPORT_SYMBOL(ZSTD_CStreamInSize);
3466 EXPORT_SYMBOL(ZSTD_CStreamOutSize);
3467 
3468 EXPORT_SYMBOL(ZSTD_getCParams);
3469 EXPORT_SYMBOL(ZSTD_getParams);
3470 EXPORT_SYMBOL(ZSTD_checkCParams);
3471 EXPORT_SYMBOL(ZSTD_adjustCParams);
3472 
3473 EXPORT_SYMBOL(ZSTD_compressBegin);
3474 EXPORT_SYMBOL(ZSTD_compressBegin_usingDict);
3475 EXPORT_SYMBOL(ZSTD_compressBegin_advanced);
3476 EXPORT_SYMBOL(ZSTD_copyCCtx);
3477 EXPORT_SYMBOL(ZSTD_compressBegin_usingCDict);
3478 EXPORT_SYMBOL(ZSTD_compressContinue);
3479 EXPORT_SYMBOL(ZSTD_compressEnd);
3480 
3481 EXPORT_SYMBOL(ZSTD_getBlockSizeMax);
3482 EXPORT_SYMBOL(ZSTD_compressBlock);
3483 
3484 MODULE_LICENSE("Dual BSD/GPL");
3485 MODULE_DESCRIPTION("Zstd Compressor");