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gerrit.opencord.org / voltha-openolt-adapter / 82efc4970cd32d794c5055d7ad2c2739e0b26fd8 / . / vendor / github.com / DataDog / zstd / zstd_decompress_block.c
blob: a2a7eedcf218ce0706f3fbd431693d09a58b3a47 [file] [log] [blame]
Abhilash S.L3b494632019-07-16 15:51:09 +0530[diff] [blame]1/*
2 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
9 */
10
11/* zstd_decompress_block :
12 * this module takes care of decompressing _compressed_ block */
13
14/*-*******************************************************
15* Dependencies
16*********************************************************/
17#include <string.h> /* memcpy, memmove, memset */
18#include "compiler.h" /* prefetch */
19#include "cpu.h" /* bmi2 */
20#include "mem.h" /* low level memory routines */
21#define FSE_STATIC_LINKING_ONLY
22#include "fse.h"
23#define HUF_STATIC_LINKING_ONLY
24#include "huf.h"
25#include "zstd_internal.h"
26#include "zstd_decompress_internal.h" /* ZSTD_DCtx */
27#include "zstd_ddict.h" /* ZSTD_DDictDictContent */
28#include "zstd_decompress_block.h"
29
30/*_*******************************************************
31* Macros
32**********************************************************/
33
34/* These two optional macros force the use one way or another of the two
35 * ZSTD_decompressSequences implementations. You can't force in both directions
36 * at the same time.
37 */
38#if defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
39 defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
40#error "Cannot force the use of the short and the long ZSTD_decompressSequences variants!"
41#endif
42
43
44/*_*******************************************************
45* Memory operations
46**********************************************************/
47static void ZSTD_copy4(void* dst, const void* src) { memcpy(dst, src, 4); }
48
49
50/*-*************************************************************
51 * Block decoding
52 ***************************************************************/
53
54/*! ZSTD_getcBlockSize() :
55 * Provides the size of compressed block from block header `src` */
56size_t ZSTD_getcBlockSize(const void* src, size_t srcSize,
57 blockProperties_t* bpPtr)
58{
59 RETURN_ERROR_IF(srcSize < ZSTD_blockHeaderSize, srcSize_wrong);
60
61 { U32 const cBlockHeader = MEM_readLE24(src);
62 U32 const cSize = cBlockHeader >> 3;
63 bpPtr->lastBlock = cBlockHeader & 1;
64 bpPtr->blockType = (blockType_e)((cBlockHeader >> 1) & 3);
65 bpPtr->origSize = cSize; /* only useful for RLE */
66 if (bpPtr->blockType == bt_rle) return 1;
67 RETURN_ERROR_IF(bpPtr->blockType == bt_reserved, corruption_detected);
68 return cSize;
69 }
70}
71
72
73/* Hidden declaration for fullbench */
74size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
75 const void* src, size_t srcSize);
76/*! ZSTD_decodeLiteralsBlock() :
77 * @return : nb of bytes read from src (< srcSize )
78 * note : symbol not declared but exposed for fullbench */
79size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
80 const void* src, size_t srcSize) /* note : srcSize < BLOCKSIZE */
81{
82 RETURN_ERROR_IF(srcSize < MIN_CBLOCK_SIZE, corruption_detected);
83
84 { const BYTE* const istart = (const BYTE*) src;
85 symbolEncodingType_e const litEncType = (symbolEncodingType_e)(istart[0] & 3);
86
87 switch(litEncType)
88 {
89 case set_repeat:
90 RETURN_ERROR_IF(dctx->litEntropy==0, dictionary_corrupted);
91 /* fall-through */
92
93 case set_compressed:
94 RETURN_ERROR_IF(srcSize < 5, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 3; here we need up to 5 for case 3");
95 { size_t lhSize, litSize, litCSize;
96 U32 singleStream=0;
97 U32 const lhlCode = (istart[0] >> 2) & 3;
98 U32 const lhc = MEM_readLE32(istart);
99 size_t hufSuccess;
100 switch(lhlCode)
101 {
102 case 0: case 1: default: /* note : default is impossible, since lhlCode into [0..3] */
103 /* 2 - 2 - 10 - 10 */
104 singleStream = !lhlCode;
105 lhSize = 3;
106 litSize = (lhc >> 4) & 0x3FF;
107 litCSize = (lhc >> 14) & 0x3FF;
108 break;
109 case 2:
110 /* 2 - 2 - 14 - 14 */
111 lhSize = 4;
112 litSize = (lhc >> 4) & 0x3FFF;
113 litCSize = lhc >> 18;
114 break;
115 case 3:
116 /* 2 - 2 - 18 - 18 */
117 lhSize = 5;
118 litSize = (lhc >> 4) & 0x3FFFF;
119 litCSize = (lhc >> 22) + (istart[4] << 10);
120 break;
121 }
122 RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected);
123 RETURN_ERROR_IF(litCSize + lhSize > srcSize, corruption_detected);
124
125 /* prefetch huffman table if cold */
126 if (dctx->ddictIsCold && (litSize > 768 /* heuristic */)) {
127 PREFETCH_AREA(dctx->HUFptr, sizeof(dctx->entropy.hufTable));
128 }
129
130 if (litEncType==set_repeat) {
131 if (singleStream) {
132 hufSuccess = HUF_decompress1X_usingDTable_bmi2(
133 dctx->litBuffer, litSize, istart+lhSize, litCSize,
134 dctx->HUFptr, dctx->bmi2);
135 } else {
136 hufSuccess = HUF_decompress4X_usingDTable_bmi2(
137 dctx->litBuffer, litSize, istart+lhSize, litCSize,
138 dctx->HUFptr, dctx->bmi2);
139 }
140 } else {
141 if (singleStream) {
142#if defined(HUF_FORCE_DECOMPRESS_X2)
143 hufSuccess = HUF_decompress1X_DCtx_wksp(
144 dctx->entropy.hufTable, dctx->litBuffer, litSize,
145 istart+lhSize, litCSize, dctx->workspace,
146 sizeof(dctx->workspace));
147#else
148 hufSuccess = HUF_decompress1X1_DCtx_wksp_bmi2(
149 dctx->entropy.hufTable, dctx->litBuffer, litSize,
150 istart+lhSize, litCSize, dctx->workspace,
151 sizeof(dctx->workspace), dctx->bmi2);
152#endif
153 } else {
154 hufSuccess = HUF_decompress4X_hufOnly_wksp_bmi2(
155 dctx->entropy.hufTable, dctx->litBuffer, litSize,
156 istart+lhSize, litCSize, dctx->workspace,
157 sizeof(dctx->workspace), dctx->bmi2);
158 }
159 }
160
161 RETURN_ERROR_IF(HUF_isError(hufSuccess), corruption_detected);
162
163 dctx->litPtr = dctx->litBuffer;
164 dctx->litSize = litSize;
165 dctx->litEntropy = 1;
166 if (litEncType==set_compressed) dctx->HUFptr = dctx->entropy.hufTable;
167 memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
168 return litCSize + lhSize;
169 }
170
171 case set_basic:
172 { size_t litSize, lhSize;
173 U32 const lhlCode = ((istart[0]) >> 2) & 3;
174 switch(lhlCode)
175 {
176 case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */
177 lhSize = 1;
178 litSize = istart[0] >> 3;
179 break;
180 case 1:
181 lhSize = 2;
182 litSize = MEM_readLE16(istart) >> 4;
183 break;
184 case 3:
185 lhSize = 3;
186 litSize = MEM_readLE24(istart) >> 4;
187 break;
188 }
189
190 if (lhSize+litSize+WILDCOPY_OVERLENGTH > srcSize) { /* risk reading beyond src buffer with wildcopy */
191 RETURN_ERROR_IF(litSize+lhSize > srcSize, corruption_detected);
192 memcpy(dctx->litBuffer, istart+lhSize, litSize);
193 dctx->litPtr = dctx->litBuffer;
194 dctx->litSize = litSize;
195 memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
196 return lhSize+litSize;
197 }
198 /* direct reference into compressed stream */
199 dctx->litPtr = istart+lhSize;
200 dctx->litSize = litSize;
201 return lhSize+litSize;
202 }
203
204 case set_rle:
205 { U32 const lhlCode = ((istart[0]) >> 2) & 3;
206 size_t litSize, lhSize;
207 switch(lhlCode)
208 {
209 case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */
210 lhSize = 1;
211 litSize = istart[0] >> 3;
212 break;
213 case 1:
214 lhSize = 2;
215 litSize = MEM_readLE16(istart) >> 4;
216 break;
217 case 3:
218 lhSize = 3;
219 litSize = MEM_readLE24(istart) >> 4;
220 RETURN_ERROR_IF(srcSize<4, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 3; here we need lhSize+1 = 4");
221 break;
222 }
223 RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected);
224 memset(dctx->litBuffer, istart[lhSize], litSize + WILDCOPY_OVERLENGTH);
225 dctx->litPtr = dctx->litBuffer;
226 dctx->litSize = litSize;
227 return lhSize+1;
228 }
229 default:
230 RETURN_ERROR(corruption_detected, "impossible");
231 }
232 }
233}
234
235/* Default FSE distribution tables.
236 * These are pre-calculated FSE decoding tables using default distributions as defined in specification :
237 * https://github.com/facebook/zstd/blob/master/doc/zstd_compression_format.md#default-distributions
238 * They were generated programmatically with following method :
239 * - start from default distributions, present in /lib/common/zstd_internal.h
240 * - generate tables normally, using ZSTD_buildFSETable()
241 * - printout the content of tables
242 * - pretify output, report below, test with fuzzer to ensure it's correct */
243
244/* Default FSE distribution table for Literal Lengths */
245static const ZSTD_seqSymbol LL_defaultDTable[(1<<LL_DEFAULTNORMLOG)+1] = {
246 { 1, 1, 1, LL_DEFAULTNORMLOG}, /* header : fastMode, tableLog */
247 /* nextState, nbAddBits, nbBits, baseVal */
248 { 0, 0, 4, 0}, { 16, 0, 4, 0},
249 { 32, 0, 5, 1}, { 0, 0, 5, 3},
250 { 0, 0, 5, 4}, { 0, 0, 5, 6},
251 { 0, 0, 5, 7}, { 0, 0, 5, 9},
252 { 0, 0, 5, 10}, { 0, 0, 5, 12},
253 { 0, 0, 6, 14}, { 0, 1, 5, 16},
254 { 0, 1, 5, 20}, { 0, 1, 5, 22},
255 { 0, 2, 5, 28}, { 0, 3, 5, 32},
256 { 0, 4, 5, 48}, { 32, 6, 5, 64},
257 { 0, 7, 5, 128}, { 0, 8, 6, 256},
258 { 0, 10, 6, 1024}, { 0, 12, 6, 4096},
259 { 32, 0, 4, 0}, { 0, 0, 4, 1},
260 { 0, 0, 5, 2}, { 32, 0, 5, 4},
261 { 0, 0, 5, 5}, { 32, 0, 5, 7},
262 { 0, 0, 5, 8}, { 32, 0, 5, 10},
263 { 0, 0, 5, 11}, { 0, 0, 6, 13},
264 { 32, 1, 5, 16}, { 0, 1, 5, 18},
265 { 32, 1, 5, 22}, { 0, 2, 5, 24},
266 { 32, 3, 5, 32}, { 0, 3, 5, 40},
267 { 0, 6, 4, 64}, { 16, 6, 4, 64},
268 { 32, 7, 5, 128}, { 0, 9, 6, 512},
269 { 0, 11, 6, 2048}, { 48, 0, 4, 0},
270 { 16, 0, 4, 1}, { 32, 0, 5, 2},
271 { 32, 0, 5, 3}, { 32, 0, 5, 5},
272 { 32, 0, 5, 6}, { 32, 0, 5, 8},
273 { 32, 0, 5, 9}, { 32, 0, 5, 11},
274 { 32, 0, 5, 12}, { 0, 0, 6, 15},
275 { 32, 1, 5, 18}, { 32, 1, 5, 20},
276 { 32, 2, 5, 24}, { 32, 2, 5, 28},
277 { 32, 3, 5, 40}, { 32, 4, 5, 48},
278 { 0, 16, 6,65536}, { 0, 15, 6,32768},
279 { 0, 14, 6,16384}, { 0, 13, 6, 8192},
280}; /* LL_defaultDTable */
281
282/* Default FSE distribution table for Offset Codes */
283static const ZSTD_seqSymbol OF_defaultDTable[(1<<OF_DEFAULTNORMLOG)+1] = {
284 { 1, 1, 1, OF_DEFAULTNORMLOG}, /* header : fastMode, tableLog */
285 /* nextState, nbAddBits, nbBits, baseVal */
286 { 0, 0, 5, 0}, { 0, 6, 4, 61},
287 { 0, 9, 5, 509}, { 0, 15, 5,32765},
288 { 0, 21, 5,2097149}, { 0, 3, 5, 5},
289 { 0, 7, 4, 125}, { 0, 12, 5, 4093},
290 { 0, 18, 5,262141}, { 0, 23, 5,8388605},
291 { 0, 5, 5, 29}, { 0, 8, 4, 253},
292 { 0, 14, 5,16381}, { 0, 20, 5,1048573},
293 { 0, 2, 5, 1}, { 16, 7, 4, 125},
294 { 0, 11, 5, 2045}, { 0, 17, 5,131069},
295 { 0, 22, 5,4194301}, { 0, 4, 5, 13},
296 { 16, 8, 4, 253}, { 0, 13, 5, 8189},
297 { 0, 19, 5,524285}, { 0, 1, 5, 1},
298 { 16, 6, 4, 61}, { 0, 10, 5, 1021},
299 { 0, 16, 5,65533}, { 0, 28, 5,268435453},
300 { 0, 27, 5,134217725}, { 0, 26, 5,67108861},
301 { 0, 25, 5,33554429}, { 0, 24, 5,16777213},
302}; /* OF_defaultDTable */
303
304
305/* Default FSE distribution table for Match Lengths */
306static const ZSTD_seqSymbol ML_defaultDTable[(1<<ML_DEFAULTNORMLOG)+1] = {
307 { 1, 1, 1, ML_DEFAULTNORMLOG}, /* header : fastMode, tableLog */
308 /* nextState, nbAddBits, nbBits, baseVal */
309 { 0, 0, 6, 3}, { 0, 0, 4, 4},
310 { 32, 0, 5, 5}, { 0, 0, 5, 6},
311 { 0, 0, 5, 8}, { 0, 0, 5, 9},
312 { 0, 0, 5, 11}, { 0, 0, 6, 13},
313 { 0, 0, 6, 16}, { 0, 0, 6, 19},
314 { 0, 0, 6, 22}, { 0, 0, 6, 25},
315 { 0, 0, 6, 28}, { 0, 0, 6, 31},
316 { 0, 0, 6, 34}, { 0, 1, 6, 37},
317 { 0, 1, 6, 41}, { 0, 2, 6, 47},
318 { 0, 3, 6, 59}, { 0, 4, 6, 83},
319 { 0, 7, 6, 131}, { 0, 9, 6, 515},
320 { 16, 0, 4, 4}, { 0, 0, 4, 5},
321 { 32, 0, 5, 6}, { 0, 0, 5, 7},
322 { 32, 0, 5, 9}, { 0, 0, 5, 10},
323 { 0, 0, 6, 12}, { 0, 0, 6, 15},
324 { 0, 0, 6, 18}, { 0, 0, 6, 21},
325 { 0, 0, 6, 24}, { 0, 0, 6, 27},
326 { 0, 0, 6, 30}, { 0, 0, 6, 33},
327 { 0, 1, 6, 35}, { 0, 1, 6, 39},
328 { 0, 2, 6, 43}, { 0, 3, 6, 51},
329 { 0, 4, 6, 67}, { 0, 5, 6, 99},
330 { 0, 8, 6, 259}, { 32, 0, 4, 4},
331 { 48, 0, 4, 4}, { 16, 0, 4, 5},
332 { 32, 0, 5, 7}, { 32, 0, 5, 8},
333 { 32, 0, 5, 10}, { 32, 0, 5, 11},
334 { 0, 0, 6, 14}, { 0, 0, 6, 17},
335 { 0, 0, 6, 20}, { 0, 0, 6, 23},
336 { 0, 0, 6, 26}, { 0, 0, 6, 29},
337 { 0, 0, 6, 32}, { 0, 16, 6,65539},
338 { 0, 15, 6,32771}, { 0, 14, 6,16387},
339 { 0, 13, 6, 8195}, { 0, 12, 6, 4099},
340 { 0, 11, 6, 2051}, { 0, 10, 6, 1027},
341}; /* ML_defaultDTable */
342
343
344static void ZSTD_buildSeqTable_rle(ZSTD_seqSymbol* dt, U32 baseValue, U32 nbAddBits)
345{
346 void* ptr = dt;
347 ZSTD_seqSymbol_header* const DTableH = (ZSTD_seqSymbol_header*)ptr;
348 ZSTD_seqSymbol* const cell = dt + 1;
349
350 DTableH->tableLog = 0;
351 DTableH->fastMode = 0;
352
353 cell->nbBits = 0;
354 cell->nextState = 0;
355 assert(nbAddBits < 255);
356 cell->nbAdditionalBits = (BYTE)nbAddBits;
357 cell->baseValue = baseValue;
358}
359
360
361/* ZSTD_buildFSETable() :
362 * generate FSE decoding table for one symbol (ll, ml or off)
363 * cannot fail if input is valid =>
364 * all inputs are presumed validated at this stage */
365void
366ZSTD_buildFSETable(ZSTD_seqSymbol* dt,
367 const short* normalizedCounter, unsigned maxSymbolValue,
368 const U32* baseValue, const U32* nbAdditionalBits,
369 unsigned tableLog)
370{
371 ZSTD_seqSymbol* const tableDecode = dt+1;
372 U16 symbolNext[MaxSeq+1];
373
374 U32 const maxSV1 = maxSymbolValue + 1;
375 U32 const tableSize = 1 << tableLog;
376 U32 highThreshold = tableSize-1;
377
378 /* Sanity Checks */
379 assert(maxSymbolValue <= MaxSeq);
380 assert(tableLog <= MaxFSELog);
381
382 /* Init, lay down lowprob symbols */
383 { ZSTD_seqSymbol_header DTableH;
384 DTableH.tableLog = tableLog;
385 DTableH.fastMode = 1;
386 { S16 const largeLimit= (S16)(1 << (tableLog-1));
387 U32 s;
388 for (s=0; s<maxSV1; s++) {
389 if (normalizedCounter[s]==-1) {
390 tableDecode[highThreshold--].baseValue = s;
391 symbolNext[s] = 1;
392 } else {
393 if (normalizedCounter[s] >= largeLimit) DTableH.fastMode=0;
394 symbolNext[s] = normalizedCounter[s];
395 } } }
396 memcpy(dt, &DTableH, sizeof(DTableH));
397 }
398
399 /* Spread symbols */
400 { U32 const tableMask = tableSize-1;
401 U32 const step = FSE_TABLESTEP(tableSize);
402 U32 s, position = 0;
403 for (s=0; s<maxSV1; s++) {
404 int i;
405 for (i=0; i<normalizedCounter[s]; i++) {
406 tableDecode[position].baseValue = s;
407 position = (position + step) & tableMask;
408 while (position > highThreshold) position = (position + step) & tableMask; /* lowprob area */
409 } }
410 assert(position == 0); /* position must reach all cells once, otherwise normalizedCounter is incorrect */
411 }
412
413 /* Build Decoding table */
414 { U32 u;
415 for (u=0; u<tableSize; u++) {
416 U32 const symbol = tableDecode[u].baseValue;
417 U32 const nextState = symbolNext[symbol]++;
418 tableDecode[u].nbBits = (BYTE) (tableLog - BIT_highbit32(nextState) );
419 tableDecode[u].nextState = (U16) ( (nextState << tableDecode[u].nbBits) - tableSize);
420 assert(nbAdditionalBits[symbol] < 255);
421 tableDecode[u].nbAdditionalBits = (BYTE)nbAdditionalBits[symbol];
422 tableDecode[u].baseValue = baseValue[symbol];
423 } }
424}
425
426
427/*! ZSTD_buildSeqTable() :
428 * @return : nb bytes read from src,
429 * or an error code if it fails */
430static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymbol** DTablePtr,
431 symbolEncodingType_e type, unsigned max, U32 maxLog,
432 const void* src, size_t srcSize,
433 const U32* baseValue, const U32* nbAdditionalBits,
434 const ZSTD_seqSymbol* defaultTable, U32 flagRepeatTable,
435 int ddictIsCold, int nbSeq)
436{
437 switch(type)
438 {
439 case set_rle :
440 RETURN_ERROR_IF(!srcSize, srcSize_wrong);
441 RETURN_ERROR_IF((*(const BYTE*)src) > max, corruption_detected);
442 { U32 const symbol = *(const BYTE*)src;
443 U32 const baseline = baseValue[symbol];
444 U32 const nbBits = nbAdditionalBits[symbol];
445 ZSTD_buildSeqTable_rle(DTableSpace, baseline, nbBits);
446 }
447 *DTablePtr = DTableSpace;
448 return 1;
449 case set_basic :
450 *DTablePtr = defaultTable;
451 return 0;
452 case set_repeat:
453 RETURN_ERROR_IF(!flagRepeatTable, corruption_detected);
454 /* prefetch FSE table if used */
455 if (ddictIsCold && (nbSeq > 24 /* heuristic */)) {
456 const void* const pStart = *DTablePtr;
457 size_t const pSize = sizeof(ZSTD_seqSymbol) * (SEQSYMBOL_TABLE_SIZE(maxLog));
458 PREFETCH_AREA(pStart, pSize);
459 }
460 return 0;
461 case set_compressed :
462 { unsigned tableLog;
463 S16 norm[MaxSeq+1];
464 size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize);
465 RETURN_ERROR_IF(FSE_isError(headerSize), corruption_detected);
466 RETURN_ERROR_IF(tableLog > maxLog, corruption_detected);
467 ZSTD_buildFSETable(DTableSpace, norm, max, baseValue, nbAdditionalBits, tableLog);
468 *DTablePtr = DTableSpace;
469 return headerSize;
470 }
471 default :
472 assert(0);
473 RETURN_ERROR(GENERIC, "impossible");
474 }
475}
476
477size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr,
478 const void* src, size_t srcSize)
479{
480 const BYTE* const istart = (const BYTE* const)src;
481 const BYTE* const iend = istart + srcSize;
482 const BYTE* ip = istart;
483 int nbSeq;
484 DEBUGLOG(5, "ZSTD_decodeSeqHeaders");
485
486 /* check */
487 RETURN_ERROR_IF(srcSize < MIN_SEQUENCES_SIZE, srcSize_wrong);
488
489 /* SeqHead */
490 nbSeq = *ip++;
491 if (!nbSeq) {
492 *nbSeqPtr=0;
493 RETURN_ERROR_IF(srcSize != 1, srcSize_wrong);
494 return 1;
495 }
496 if (nbSeq > 0x7F) {
497 if (nbSeq == 0xFF) {
498 RETURN_ERROR_IF(ip+2 > iend, srcSize_wrong);
499 nbSeq = MEM_readLE16(ip) + LONGNBSEQ, ip+=2;
500 } else {
501 RETURN_ERROR_IF(ip >= iend, srcSize_wrong);
502 nbSeq = ((nbSeq-0x80)<<8) + *ip++;
503 }
504 }
505 *nbSeqPtr = nbSeq;
506
507 /* FSE table descriptors */
508 RETURN_ERROR_IF(ip+4 > iend, srcSize_wrong); /* minimum possible size */
509 { symbolEncodingType_e const LLtype = (symbolEncodingType_e)(*ip >> 6);
510 symbolEncodingType_e const OFtype = (symbolEncodingType_e)((*ip >> 4) & 3);
511 symbolEncodingType_e const MLtype = (symbolEncodingType_e)((*ip >> 2) & 3);
512 ip++;
513
514 /* Build DTables */
515 { size_t const llhSize = ZSTD_buildSeqTable(dctx->entropy.LLTable, &dctx->LLTptr,
516 LLtype, MaxLL, LLFSELog,
517 ip, iend-ip,
518 LL_base, LL_bits,
519 LL_defaultDTable, dctx->fseEntropy,
520 dctx->ddictIsCold, nbSeq);
521 RETURN_ERROR_IF(ZSTD_isError(llhSize), corruption_detected);
522 ip += llhSize;
523 }
524
525 { size_t const ofhSize = ZSTD_buildSeqTable(dctx->entropy.OFTable, &dctx->OFTptr,
526 OFtype, MaxOff, OffFSELog,
527 ip, iend-ip,
528 OF_base, OF_bits,
529 OF_defaultDTable, dctx->fseEntropy,
530 dctx->ddictIsCold, nbSeq);
531 RETURN_ERROR_IF(ZSTD_isError(ofhSize), corruption_detected);
532 ip += ofhSize;
533 }
534
535 { size_t const mlhSize = ZSTD_buildSeqTable(dctx->entropy.MLTable, &dctx->MLTptr,
536 MLtype, MaxML, MLFSELog,
537 ip, iend-ip,
538 ML_base, ML_bits,
539 ML_defaultDTable, dctx->fseEntropy,
540 dctx->ddictIsCold, nbSeq);
541 RETURN_ERROR_IF(ZSTD_isError(mlhSize), corruption_detected);
542 ip += mlhSize;
543 }
544 }
545
546 return ip-istart;
547}
548
549
550typedef struct {
551 size_t litLength;
552 size_t matchLength;
553 size_t offset;
554 const BYTE* match;
555} seq_t;
556
557typedef struct {
558 size_t state;
559 const ZSTD_seqSymbol* table;
560} ZSTD_fseState;
561
562typedef struct {
563 BIT_DStream_t DStream;
564 ZSTD_fseState stateLL;
565 ZSTD_fseState stateOffb;
566 ZSTD_fseState stateML;
567 size_t prevOffset[ZSTD_REP_NUM];
568 const BYTE* prefixStart;
569 const BYTE* dictEnd;
570 size_t pos;
571} seqState_t;
572
573
574/* ZSTD_execSequenceLast7():
575 * exceptional case : decompress a match starting within last 7 bytes of output buffer.
576 * requires more careful checks, to ensure there is no overflow.
577 * performance does not matter though.
578 * note : this case is supposed to be never generated "naturally" by reference encoder,
579 * since in most cases it needs at least 8 bytes to look for a match.
580 * but it's allowed by the specification. */
581FORCE_NOINLINE
582size_t ZSTD_execSequenceLast7(BYTE* op,
583 BYTE* const oend, seq_t sequence,
584 const BYTE** litPtr, const BYTE* const litLimit,
585 const BYTE* const base, const BYTE* const vBase, const BYTE* const dictEnd)
586{
587 BYTE* const oLitEnd = op + sequence.litLength;
588 size_t const sequenceLength = sequence.litLength + sequence.matchLength;
589 BYTE* const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
590 const BYTE* const iLitEnd = *litPtr + sequence.litLength;
591 const BYTE* match = oLitEnd - sequence.offset;
592
593 /* check */
594 RETURN_ERROR_IF(oMatchEnd>oend, dstSize_tooSmall, "last match must fit within dstBuffer");
595 RETURN_ERROR_IF(iLitEnd > litLimit, corruption_detected, "try to read beyond literal buffer");
596
597 /* copy literals */
598 while (op < oLitEnd) *op++ = *(*litPtr)++;
599
600 /* copy Match */
601 if (sequence.offset > (size_t)(oLitEnd - base)) {
602 /* offset beyond prefix */
603 RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - vBase),corruption_detected);
604 match = dictEnd - (base-match);
605 if (match + sequence.matchLength <= dictEnd) {
606 memmove(oLitEnd, match, sequence.matchLength);
607 return sequenceLength;
608 }
609 /* span extDict & currentPrefixSegment */
610 { size_t const length1 = dictEnd - match;
611 memmove(oLitEnd, match, length1);
612 op = oLitEnd + length1;
613 sequence.matchLength -= length1;
614 match = base;
615 } }
616 while (op < oMatchEnd) *op++ = *match++;
617 return sequenceLength;
618}
619
620
621HINT_INLINE
622size_t ZSTD_execSequence(BYTE* op,
623 BYTE* const oend, seq_t sequence,
624 const BYTE** litPtr, const BYTE* const litLimit,
625 const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd)
626{
627 BYTE* const oLitEnd = op + sequence.litLength;
628 size_t const sequenceLength = sequence.litLength + sequence.matchLength;
629 BYTE* const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
630 BYTE* const oend_w = oend - WILDCOPY_OVERLENGTH;
631 const BYTE* const iLitEnd = *litPtr + sequence.litLength;
632 const BYTE* match = oLitEnd - sequence.offset;
633
634 /* check */
635 RETURN_ERROR_IF(oMatchEnd>oend, dstSize_tooSmall, "last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend");
636 RETURN_ERROR_IF(iLitEnd > litLimit, corruption_detected, "over-read beyond lit buffer");
637 if (oLitEnd>oend_w) return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, prefixStart, virtualStart, dictEnd);
638
639 /* copy Literals */
640 ZSTD_copy8(op, *litPtr);
641 if (sequence.litLength > 8)
642 ZSTD_wildcopy(op+8, (*litPtr)+8, sequence.litLength - 8); /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
643 op = oLitEnd;
644 *litPtr = iLitEnd; /* update for next sequence */
645
646 /* copy Match */
647 if (sequence.offset > (size_t)(oLitEnd - prefixStart)) {
648 /* offset beyond prefix -> go into extDict */
649 RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - virtualStart), corruption_detected);
650 match = dictEnd + (match - prefixStart);
651 if (match + sequence.matchLength <= dictEnd) {
652 memmove(oLitEnd, match, sequence.matchLength);
653 return sequenceLength;
654 }
655 /* span extDict & currentPrefixSegment */
656 { size_t const length1 = dictEnd - match;
657 memmove(oLitEnd, match, length1);
658 op = oLitEnd + length1;
659 sequence.matchLength -= length1;
660 match = prefixStart;
661 if (op > oend_w || sequence.matchLength < MINMATCH) {
662 U32 i;
663 for (i = 0; i < sequence.matchLength; ++i) op[i] = match[i];
664 return sequenceLength;
665 }
666 } }
667 /* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
668
669 /* match within prefix */
670 if (sequence.offset < 8) {
671 /* close range match, overlap */
672 static const U32 dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 }; /* added */
673 static const int dec64table[] = { 8, 8, 8, 7, 8, 9,10,11 }; /* subtracted */
674 int const sub2 = dec64table[sequence.offset];
675 op[0] = match[0];
676 op[1] = match[1];
677 op[2] = match[2];
678 op[3] = match[3];
679 match += dec32table[sequence.offset];
680 ZSTD_copy4(op+4, match);
681 match -= sub2;
682 } else {
683 ZSTD_copy8(op, match);
684 }
685 op += 8; match += 8;
686
687 if (oMatchEnd > oend-(16-MINMATCH)) {
688 if (op < oend_w) {
689 ZSTD_wildcopy(op, match, oend_w - op);
690 match += oend_w - op;
691 op = oend_w;
692 }
693 while (op < oMatchEnd) *op++ = *match++;
694 } else {
695 ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength-8); /* works even if matchLength < 8 */
696 }
697 return sequenceLength;
698}
699
700
701HINT_INLINE
702size_t ZSTD_execSequenceLong(BYTE* op,
703 BYTE* const oend, seq_t sequence,
704 const BYTE** litPtr, const BYTE* const litLimit,
705 const BYTE* const prefixStart, const BYTE* const dictStart, const BYTE* const dictEnd)
706{
707 BYTE* const oLitEnd = op + sequence.litLength;
708 size_t const sequenceLength = sequence.litLength + sequence.matchLength;
709 BYTE* const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
710 BYTE* const oend_w = oend - WILDCOPY_OVERLENGTH;
711 const BYTE* const iLitEnd = *litPtr + sequence.litLength;
712 const BYTE* match = sequence.match;
713
714 /* check */
715 RETURN_ERROR_IF(oMatchEnd > oend, dstSize_tooSmall, "last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend");
716 RETURN_ERROR_IF(iLitEnd > litLimit, corruption_detected, "over-read beyond lit buffer");
717 if (oLitEnd > oend_w) return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, prefixStart, dictStart, dictEnd);
718
719 /* copy Literals */
720 ZSTD_copy8(op, *litPtr); /* note : op <= oLitEnd <= oend_w == oend - 8 */
721 if (sequence.litLength > 8)
722 ZSTD_wildcopy(op+8, (*litPtr)+8, sequence.litLength - 8); /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
723 op = oLitEnd;
724 *litPtr = iLitEnd; /* update for next sequence */
725
726 /* copy Match */
727 if (sequence.offset > (size_t)(oLitEnd - prefixStart)) {
728 /* offset beyond prefix */
729 RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - dictStart), corruption_detected);
730 if (match + sequence.matchLength <= dictEnd) {
731 memmove(oLitEnd, match, sequence.matchLength);
732 return sequenceLength;
733 }
734 /* span extDict & currentPrefixSegment */
735 { size_t const length1 = dictEnd - match;
736 memmove(oLitEnd, match, length1);
737 op = oLitEnd + length1;
738 sequence.matchLength -= length1;
739 match = prefixStart;
740 if (op > oend_w || sequence.matchLength < MINMATCH) {
741 U32 i;
742 for (i = 0; i < sequence.matchLength; ++i) op[i] = match[i];
743 return sequenceLength;
744 }
745 } }
746 assert(op <= oend_w);
747 assert(sequence.matchLength >= MINMATCH);
748
749 /* match within prefix */
750 if (sequence.offset < 8) {
751 /* close range match, overlap */
752 static const U32 dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 }; /* added */
753 static const int dec64table[] = { 8, 8, 8, 7, 8, 9,10,11 }; /* subtracted */
754 int const sub2 = dec64table[sequence.offset];
755 op[0] = match[0];
756 op[1] = match[1];
757 op[2] = match[2];
758 op[3] = match[3];
759 match += dec32table[sequence.offset];
760 ZSTD_copy4(op+4, match);
761 match -= sub2;
762 } else {
763 ZSTD_copy8(op, match);
764 }
765 op += 8; match += 8;
766
767 if (oMatchEnd > oend-(16-MINMATCH)) {
768 if (op < oend_w) {
769 ZSTD_wildcopy(op, match, oend_w - op);
770 match += oend_w - op;
771 op = oend_w;
772 }
773 while (op < oMatchEnd) *op++ = *match++;
774 } else {
775 ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength-8); /* works even if matchLength < 8 */
776 }
777 return sequenceLength;
778}
779
780static void
781ZSTD_initFseState(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, const ZSTD_seqSymbol* dt)
782{
783 const void* ptr = dt;
784 const ZSTD_seqSymbol_header* const DTableH = (const ZSTD_seqSymbol_header*)ptr;
785 DStatePtr->state = BIT_readBits(bitD, DTableH->tableLog);
786 DEBUGLOG(6, "ZSTD_initFseState : val=%u using %u bits",
787 (U32)DStatePtr->state, DTableH->tableLog);
788 BIT_reloadDStream(bitD);
789 DStatePtr->table = dt + 1;
790}
791
792FORCE_INLINE_TEMPLATE void
793ZSTD_updateFseState(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD)
794{
795 ZSTD_seqSymbol const DInfo = DStatePtr->table[DStatePtr->state];
796 U32 const nbBits = DInfo.nbBits;
797 size_t const lowBits = BIT_readBits(bitD, nbBits);
798 DStatePtr->state = DInfo.nextState + lowBits;
799}
800
801/* We need to add at most (ZSTD_WINDOWLOG_MAX_32 - 1) bits to read the maximum
802 * offset bits. But we can only read at most (STREAM_ACCUMULATOR_MIN_32 - 1)
803 * bits before reloading. This value is the maximum number of bytes we read
804 * after reloading when we are decoding long offsets.
805 */
806#define LONG_OFFSETS_MAX_EXTRA_BITS_32 \
807 (ZSTD_WINDOWLOG_MAX_32 > STREAM_ACCUMULATOR_MIN_32 \
808 ? ZSTD_WINDOWLOG_MAX_32 - STREAM_ACCUMULATOR_MIN_32 \
809 : 0)
810
811typedef enum { ZSTD_lo_isRegularOffset, ZSTD_lo_isLongOffset=1 } ZSTD_longOffset_e;
812
813#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
814FORCE_INLINE_TEMPLATE seq_t
815ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets)
816{
817 seq_t seq;
818 U32 const llBits = seqState->stateLL.table[seqState->stateLL.state].nbAdditionalBits;
819 U32 const mlBits = seqState->stateML.table[seqState->stateML.state].nbAdditionalBits;
820 U32 const ofBits = seqState->stateOffb.table[seqState->stateOffb.state].nbAdditionalBits;
821 U32 const totalBits = llBits+mlBits+ofBits;
822 U32 const llBase = seqState->stateLL.table[seqState->stateLL.state].baseValue;
823 U32 const mlBase = seqState->stateML.table[seqState->stateML.state].baseValue;
824 U32 const ofBase = seqState->stateOffb.table[seqState->stateOffb.state].baseValue;
825
826 /* sequence */
827 { size_t offset;
828 if (!ofBits)
829 offset = 0;
830 else {
831 ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1);
832 ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 5);
833 assert(ofBits <= MaxOff);
834 if (MEM_32bits() && longOffsets && (ofBits >= STREAM_ACCUMULATOR_MIN_32)) {
835 U32 const extraBits = ofBits - MIN(ofBits, 32 - seqState->DStream.bitsConsumed);
836 offset = ofBase + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
837 BIT_reloadDStream(&seqState->DStream);
838 if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits);
839 assert(extraBits <= LONG_OFFSETS_MAX_EXTRA_BITS_32); /* to avoid another reload */
840 } else {
841 offset = ofBase + BIT_readBitsFast(&seqState->DStream, ofBits/*>0*/); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */
842 if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream);
843 }
844 }
845
846 if (ofBits <= 1) {
847 offset += (llBase==0);
848 if (offset) {
849 size_t temp = (offset==3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
850 temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */
851 if (offset != 1) seqState->prevOffset[2] = seqState->prevOffset[1];
852 seqState->prevOffset[1] = seqState->prevOffset[0];
853 seqState->prevOffset[0] = offset = temp;
854 } else { /* offset == 0 */
855 offset = seqState->prevOffset[0];
856 }
857 } else {
858 seqState->prevOffset[2] = seqState->prevOffset[1];
859 seqState->prevOffset[1] = seqState->prevOffset[0];
860 seqState->prevOffset[0] = offset;
861 }
862 seq.offset = offset;
863 }
864
865 seq.matchLength = mlBase
866 + ((mlBits>0) ? BIT_readBitsFast(&seqState->DStream, mlBits/*>0*/) : 0); /* <= 16 bits */
867 if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32))
868 BIT_reloadDStream(&seqState->DStream);
869 if (MEM_64bits() && (totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog)))
870 BIT_reloadDStream(&seqState->DStream);
871 /* Ensure there are enough bits to read the rest of data in 64-bit mode. */
872 ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64);
873
874 seq.litLength = llBase
875 + ((llBits>0) ? BIT_readBitsFast(&seqState->DStream, llBits/*>0*/) : 0); /* <= 16 bits */
876 if (MEM_32bits())
877 BIT_reloadDStream(&seqState->DStream);
878
879 DEBUGLOG(6, "seq: litL=%u, matchL=%u, offset=%u",
880 (U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset);
881
882 /* ANS state update */
883 ZSTD_updateFseState(&seqState->stateLL, &seqState->DStream); /* <= 9 bits */
884 ZSTD_updateFseState(&seqState->stateML, &seqState->DStream); /* <= 9 bits */
885 if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */
886 ZSTD_updateFseState(&seqState->stateOffb, &seqState->DStream); /* <= 8 bits */
887
888 return seq;
889}
890
891FORCE_INLINE_TEMPLATE size_t
892ZSTD_decompressSequences_body( ZSTD_DCtx* dctx,
893 void* dst, size_t maxDstSize,
894 const void* seqStart, size_t seqSize, int nbSeq,
895 const ZSTD_longOffset_e isLongOffset)
896{
897 const BYTE* ip = (const BYTE*)seqStart;
898 const BYTE* const iend = ip + seqSize;
899 BYTE* const ostart = (BYTE* const)dst;
900 BYTE* const oend = ostart + maxDstSize;
901 BYTE* op = ostart;
902 const BYTE* litPtr = dctx->litPtr;
903 const BYTE* const litEnd = litPtr + dctx->litSize;
904 const BYTE* const prefixStart = (const BYTE*) (dctx->prefixStart);
905 const BYTE* const vBase = (const BYTE*) (dctx->virtualStart);
906 const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
907 DEBUGLOG(5, "ZSTD_decompressSequences_body");
908
909 /* Regen sequences */
910 if (nbSeq) {
911 seqState_t seqState;
912 dctx->fseEntropy = 1;
913 { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; }
914 RETURN_ERROR_IF(
915 ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend-ip)),
916 corruption_detected);
917 ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
918 ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
919 ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
920
921 for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && nbSeq ; ) {
922 nbSeq--;
923 { seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset);
924 size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, prefixStart, vBase, dictEnd);
925 DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize);
926 if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
927 op += oneSeqSize;
928 } }
929
930 /* check if reached exact end */
931 DEBUGLOG(5, "ZSTD_decompressSequences_body: after decode loop, remaining nbSeq : %i", nbSeq);
932 RETURN_ERROR_IF(nbSeq, corruption_detected);
933 /* save reps for next block */
934 { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]); }
935 }
936
937 /* last literal segment */
938 { size_t const lastLLSize = litEnd - litPtr;
939 RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall);
940 memcpy(op, litPtr, lastLLSize);
941 op += lastLLSize;
942 }
943
944 return op-ostart;
945}
946
947static size_t
948ZSTD_decompressSequences_default(ZSTD_DCtx* dctx,
949 void* dst, size_t maxDstSize,
950 const void* seqStart, size_t seqSize, int nbSeq,
951 const ZSTD_longOffset_e isLongOffset)
952{
953 return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
954}
955#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */
956
957
958
959#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT
960FORCE_INLINE_TEMPLATE seq_t
961ZSTD_decodeSequenceLong(seqState_t* seqState, ZSTD_longOffset_e const longOffsets)
962{
963 seq_t seq;
964 U32 const llBits = seqState->stateLL.table[seqState->stateLL.state].nbAdditionalBits;
965 U32 const mlBits = seqState->stateML.table[seqState->stateML.state].nbAdditionalBits;
966 U32 const ofBits = seqState->stateOffb.table[seqState->stateOffb.state].nbAdditionalBits;
967 U32 const totalBits = llBits+mlBits+ofBits;
968 U32 const llBase = seqState->stateLL.table[seqState->stateLL.state].baseValue;
969 U32 const mlBase = seqState->stateML.table[seqState->stateML.state].baseValue;
970 U32 const ofBase = seqState->stateOffb.table[seqState->stateOffb.state].baseValue;
971
972 /* sequence */
973 { size_t offset;
974 if (!ofBits)
975 offset = 0;
976 else {
977 ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1);
978 ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 5);
979 assert(ofBits <= MaxOff);
980 if (MEM_32bits() && longOffsets) {
981 U32 const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN_32-1);
982 offset = ofBase + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
983 if (MEM_32bits() || extraBits) BIT_reloadDStream(&seqState->DStream);
984 if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits);
985 } else {
986 offset = ofBase + BIT_readBitsFast(&seqState->DStream, ofBits); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */
987 if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream);
988 }
989 }
990
991 if (ofBits <= 1) {
992 offset += (llBase==0);
993 if (offset) {
994 size_t temp = (offset==3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
995 temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */
996 if (offset != 1) seqState->prevOffset[2] = seqState->prevOffset[1];
997 seqState->prevOffset[1] = seqState->prevOffset[0];
998 seqState->prevOffset[0] = offset = temp;
999 } else {
1000 offset = seqState->prevOffset[0];
1001 }
1002 } else {
1003 seqState->prevOffset[2] = seqState->prevOffset[1];
1004 seqState->prevOffset[1] = seqState->prevOffset[0];
1005 seqState->prevOffset[0] = offset;
1006 }
1007 seq.offset = offset;
1008 }
1009
1010 seq.matchLength = mlBase + ((mlBits>0) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <= 16 bits */
1011 if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32))
1012 BIT_reloadDStream(&seqState->DStream);
1013 if (MEM_64bits() && (totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog)))
1014 BIT_reloadDStream(&seqState->DStream);
1015 /* Verify that there is enough bits to read the rest of the data in 64-bit mode. */
1016 ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64);
1017
1018 seq.litLength = llBase + ((llBits>0) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <= 16 bits */
1019 if (MEM_32bits())
1020 BIT_reloadDStream(&seqState->DStream);
1021
1022 { size_t const pos = seqState->pos + seq.litLength;
1023 const BYTE* const matchBase = (seq.offset > pos) ? seqState->dictEnd : seqState->prefixStart;
1024 seq.match = matchBase + pos - seq.offset; /* note : this operation can overflow when seq.offset is really too large, which can only happen when input is corrupted.
1025 * No consequence though : no memory access will occur, overly large offset will be detected in ZSTD_execSequenceLong() */
1026 seqState->pos = pos + seq.matchLength;
1027 }
1028
1029 /* ANS state update */
1030 ZSTD_updateFseState(&seqState->stateLL, &seqState->DStream); /* <= 9 bits */
1031 ZSTD_updateFseState(&seqState->stateML, &seqState->DStream); /* <= 9 bits */
1032 if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */
1033 ZSTD_updateFseState(&seqState->stateOffb, &seqState->DStream); /* <= 8 bits */
1034
1035 return seq;
1036}
1037
1038FORCE_INLINE_TEMPLATE size_t
1039ZSTD_decompressSequencesLong_body(
1040 ZSTD_DCtx* dctx,
1041 void* dst, size_t maxDstSize,
1042 const void* seqStart, size_t seqSize, int nbSeq,
1043 const ZSTD_longOffset_e isLongOffset)
1044{
1045 const BYTE* ip = (const BYTE*)seqStart;
1046 const BYTE* const iend = ip + seqSize;
1047 BYTE* const ostart = (BYTE* const)dst;
1048 BYTE* const oend = ostart + maxDstSize;
1049 BYTE* op = ostart;
1050 const BYTE* litPtr = dctx->litPtr;
1051 const BYTE* const litEnd = litPtr + dctx->litSize;
1052 const BYTE* const prefixStart = (const BYTE*) (dctx->prefixStart);
1053 const BYTE* const dictStart = (const BYTE*) (dctx->virtualStart);
1054 const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
1055
1056 /* Regen sequences */
1057 if (nbSeq) {
1058#define STORED_SEQS 4
1059#define STORED_SEQS_MASK (STORED_SEQS-1)
1060#define ADVANCED_SEQS 4
1061 seq_t sequences[STORED_SEQS];
1062 int const seqAdvance = MIN(nbSeq, ADVANCED_SEQS);
1063 seqState_t seqState;
1064 int seqNb;
1065 dctx->fseEntropy = 1;
1066 { int i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; }
1067 seqState.prefixStart = prefixStart;
1068 seqState.pos = (size_t)(op-prefixStart);
1069 seqState.dictEnd = dictEnd;
1070 assert(iend >= ip);
1071 RETURN_ERROR_IF(
1072 ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend-ip)),
1073 corruption_detected);
1074 ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
1075 ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
1076 ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
1077
1078 /* prepare in advance */
1079 for (seqNb=0; (BIT_reloadDStream(&seqState.DStream) <= BIT_DStream_completed) && (seqNb<seqAdvance); seqNb++) {
1080 sequences[seqNb] = ZSTD_decodeSequenceLong(&seqState, isLongOffset);
1081 PREFETCH_L1(sequences[seqNb].match); PREFETCH_L1(sequences[seqNb].match + sequences[seqNb].matchLength - 1); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */
1082 }
1083 RETURN_ERROR_IF(seqNb<seqAdvance, corruption_detected);
1084
1085 /* decode and decompress */
1086 for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && (seqNb<nbSeq) ; seqNb++) {
1087 seq_t const sequence = ZSTD_decodeSequenceLong(&seqState, isLongOffset);
1088 size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[(seqNb-ADVANCED_SEQS) & STORED_SEQS_MASK], &litPtr, litEnd, prefixStart, dictStart, dictEnd);
1089 if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
1090 PREFETCH_L1(sequence.match); PREFETCH_L1(sequence.match + sequence.matchLength - 1); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */
1091 sequences[seqNb & STORED_SEQS_MASK] = sequence;
1092 op += oneSeqSize;
1093 }
1094 RETURN_ERROR_IF(seqNb<nbSeq, corruption_detected);
1095
1096 /* finish queue */
1097 seqNb -= seqAdvance;
1098 for ( ; seqNb<nbSeq ; seqNb++) {
1099 size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[seqNb&STORED_SEQS_MASK], &litPtr, litEnd, prefixStart, dictStart, dictEnd);
1100 if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
1101 op += oneSeqSize;
1102 }
1103
1104 /* save reps for next block */
1105 { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]); }
1106 }
1107
1108 /* last literal segment */
1109 { size_t const lastLLSize = litEnd - litPtr;
1110 RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall);
1111 memcpy(op, litPtr, lastLLSize);
1112 op += lastLLSize;
1113 }
1114
1115 return op-ostart;
1116}
1117
1118static size_t
1119ZSTD_decompressSequencesLong_default(ZSTD_DCtx* dctx,
1120 void* dst, size_t maxDstSize,
1121 const void* seqStart, size_t seqSize, int nbSeq,
1122 const ZSTD_longOffset_e isLongOffset)
1123{
1124 return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
1125}
1126#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */
1127
1128
1129
1130#if DYNAMIC_BMI2
1131
1132#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
1133static TARGET_ATTRIBUTE("bmi2") size_t
1134ZSTD_decompressSequences_bmi2(ZSTD_DCtx* dctx,
1135 void* dst, size_t maxDstSize,
1136 const void* seqStart, size_t seqSize, int nbSeq,
1137 const ZSTD_longOffset_e isLongOffset)
1138{
1139 return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
1140}
1141#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */
1142
1143#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT
1144static TARGET_ATTRIBUTE("bmi2") size_t
1145ZSTD_decompressSequencesLong_bmi2(ZSTD_DCtx* dctx,
1146 void* dst, size_t maxDstSize,
1147 const void* seqStart, size_t seqSize, int nbSeq,
1148 const ZSTD_longOffset_e isLongOffset)
1149{
1150 return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
1151}
1152#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */
1153
1154#endif /* DYNAMIC_BMI2 */
1155
1156typedef size_t (*ZSTD_decompressSequences_t)(
1157 ZSTD_DCtx* dctx,
1158 void* dst, size_t maxDstSize,
1159 const void* seqStart, size_t seqSize, int nbSeq,
1160 const ZSTD_longOffset_e isLongOffset);
1161
1162#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
1163static size_t
1164ZSTD_decompressSequences(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize,
1165 const void* seqStart, size_t seqSize, int nbSeq,
1166 const ZSTD_longOffset_e isLongOffset)
1167{
1168 DEBUGLOG(5, "ZSTD_decompressSequences");
1169#if DYNAMIC_BMI2
1170 if (dctx->bmi2) {
1171 return ZSTD_decompressSequences_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
1172 }
1173#endif
1174 return ZSTD_decompressSequences_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
1175}
1176#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */
1177
1178
1179#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT
1180/* ZSTD_decompressSequencesLong() :
1181 * decompression function triggered when a minimum share of offsets is considered "long",
1182 * aka out of cache.
1183 * note : "long" definition seems overloaded here, sometimes meaning "wider than bitstream register", and sometimes meaning "farther than memory cache distance".
1184 * This function will try to mitigate main memory latency through the use of prefetching */
1185static size_t
1186ZSTD_decompressSequencesLong(ZSTD_DCtx* dctx,
1187 void* dst, size_t maxDstSize,
1188 const void* seqStart, size_t seqSize, int nbSeq,
1189 const ZSTD_longOffset_e isLongOffset)
1190{
1191 DEBUGLOG(5, "ZSTD_decompressSequencesLong");
1192#if DYNAMIC_BMI2
1193 if (dctx->bmi2) {
1194 return ZSTD_decompressSequencesLong_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
1195 }
1196#endif
1197 return ZSTD_decompressSequencesLong_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
1198}
1199#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */
1200
1201
1202
1203#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
1204 !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
1205/* ZSTD_getLongOffsetsShare() :
1206 * condition : offTable must be valid
1207 * @return : "share" of long offsets (arbitrarily defined as > (1<<23))
1208 * compared to maximum possible of (1<<OffFSELog) */
1209static unsigned
1210ZSTD_getLongOffsetsShare(const ZSTD_seqSymbol* offTable)
1211{
1212 const void* ptr = offTable;
1213 U32 const tableLog = ((const ZSTD_seqSymbol_header*)ptr)[0].tableLog;
1214 const ZSTD_seqSymbol* table = offTable + 1;
1215 U32 const max = 1 << tableLog;
1216 U32 u, total = 0;
1217 DEBUGLOG(5, "ZSTD_getLongOffsetsShare: (tableLog=%u)", tableLog);
1218
1219 assert(max <= (1 << OffFSELog)); /* max not too large */
1220 for (u=0; u<max; u++) {
1221 if (table[u].nbAdditionalBits > 22) total += 1;
1222 }
1223
1224 assert(tableLog <= OffFSELog);
1225 total <<= (OffFSELog - tableLog); /* scale to OffFSELog */
1226
1227 return total;
1228}
1229#endif
1230
1231
1232size_t
1233ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx,
1234 void* dst, size_t dstCapacity,
1235 const void* src, size_t srcSize, const int frame)
1236{ /* blockType == blockCompressed */
1237 const BYTE* ip = (const BYTE*)src;
1238 /* isLongOffset must be true if there are long offsets.
1239 * Offsets are long if they are larger than 2^STREAM_ACCUMULATOR_MIN.
1240 * We don't expect that to be the case in 64-bit mode.
1241 * In block mode, window size is not known, so we have to be conservative.
1242 * (note: but it could be evaluated from current-lowLimit)
1243 */
1244 ZSTD_longOffset_e const isLongOffset = (ZSTD_longOffset_e)(MEM_32bits() && (!frame || (dctx->fParams.windowSize > (1ULL << STREAM_ACCUMULATOR_MIN))));
1245 DEBUGLOG(5, "ZSTD_decompressBlock_internal (size : %u)", (U32)srcSize);
1246
1247 RETURN_ERROR_IF(srcSize >= ZSTD_BLOCKSIZE_MAX, srcSize_wrong);
1248
1249 /* Decode literals section */
1250 { size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize);
1251 DEBUGLOG(5, "ZSTD_decodeLiteralsBlock : %u", (U32)litCSize);
1252 if (ZSTD_isError(litCSize)) return litCSize;
1253 ip += litCSize;
1254 srcSize -= litCSize;
1255 }
1256
1257 /* Build Decoding Tables */
1258 {
1259 /* These macros control at build-time which decompressor implementation
1260 * we use. If neither is defined, we do some inspection and dispatch at
1261 * runtime.
1262 */
1263#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
1264 !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
1265 int usePrefetchDecoder = dctx->ddictIsCold;
1266#endif
1267 int nbSeq;
1268 size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, srcSize);
1269 if (ZSTD_isError(seqHSize)) return seqHSize;
1270 ip += seqHSize;
1271 srcSize -= seqHSize;
1272
1273#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
1274 !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
1275 if ( !usePrefetchDecoder
1276 && (!frame || (dctx->fParams.windowSize > (1<<24)))
1277 && (nbSeq>ADVANCED_SEQS) ) { /* could probably use a larger nbSeq limit */
1278 U32 const shareLongOffsets = ZSTD_getLongOffsetsShare(dctx->OFTptr);
1279 U32 const minShare = MEM_64bits() ? 7 : 20; /* heuristic values, correspond to 2.73% and 7.81% */
1280 usePrefetchDecoder = (shareLongOffsets >= minShare);
1281 }
1282#endif
1283
1284 dctx->ddictIsCold = 0;
1285
1286#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
1287 !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
1288 if (usePrefetchDecoder)
1289#endif
1290#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT
1291 return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset);
1292#endif
1293
1294#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
1295 /* else */
1296 return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset);
1297#endif
1298 }
1299}
1300
1301
1302size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx,
1303 void* dst, size_t dstCapacity,
1304 const void* src, size_t srcSize)
1305{
1306 size_t dSize;
1307 ZSTD_checkContinuity(dctx, dst);
1308 dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 0);
1309 dctx->previousDstEnd = (char*)dst + dSize;
1310 return dSize;
1311}