decompress.c 80 KB

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  1. // SPDX-License-Identifier: (GPL-2.0 or BSD-3-Clause-Clear)
  2. /**
  3. * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
  4. * All rights reserved.
  5. */
  6. /* ***************************************************************
  7. * Tuning parameters
  8. *****************************************************************/
  9. /*!
  10. * MAXWINDOWSIZE_DEFAULT :
  11. * maximum window size accepted by DStream, by default.
  12. * Frames requiring more memory will be rejected.
  13. */
  14. #ifndef ZSTD_MAXWINDOWSIZE_DEFAULT
  15. #define ZSTD_MAXWINDOWSIZE_DEFAULT ((1 << ZSTD_WINDOWLOG_MAX) + 1) /* defined within zstd.h */
  16. #endif
  17. /*-*******************************************************
  18. * Dependencies
  19. *********************************************************/
  20. #include "fse.h"
  21. #include "huf.h"
  22. #include "mem.h" /* low level memory routines */
  23. #include "zstd_internal.h"
  24. #include <malloc.h>
  25. #include <linux/kernel.h>
  26. #include <linux/compat.h>
  27. #include <linux/string.h> /* memcpy, memmove, memset */
  28. #define ZSTD_PREFETCH(ptr) __builtin_prefetch(ptr, 0, 0)
  29. /*-*************************************
  30. * Macros
  31. ***************************************/
  32. #define ZSTD_isError ERR_isError /* for inlining */
  33. #define FSE_isError ERR_isError
  34. #define HUF_isError ERR_isError
  35. /*_*******************************************************
  36. * Memory operations
  37. **********************************************************/
  38. static void ZSTD_copy4(void *dst, const void *src) { memcpy(dst, src, 4); }
  39. /*-*************************************************************
  40. * Context management
  41. ***************************************************************/
  42. typedef enum {
  43. ZSTDds_getFrameHeaderSize,
  44. ZSTDds_decodeFrameHeader,
  45. ZSTDds_decodeBlockHeader,
  46. ZSTDds_decompressBlock,
  47. ZSTDds_decompressLastBlock,
  48. ZSTDds_checkChecksum,
  49. ZSTDds_decodeSkippableHeader,
  50. ZSTDds_skipFrame
  51. } ZSTD_dStage;
  52. typedef struct {
  53. FSE_DTable LLTable[FSE_DTABLE_SIZE_U32(LLFSELog)];
  54. FSE_DTable OFTable[FSE_DTABLE_SIZE_U32(OffFSELog)];
  55. FSE_DTable MLTable[FSE_DTABLE_SIZE_U32(MLFSELog)];
  56. HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)]; /* can accommodate HUF_decompress4X */
  57. U64 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32 / 2];
  58. U32 rep[ZSTD_REP_NUM];
  59. } ZSTD_entropyTables_t;
  60. struct ZSTD_DCtx_s {
  61. const FSE_DTable *LLTptr;
  62. const FSE_DTable *MLTptr;
  63. const FSE_DTable *OFTptr;
  64. const HUF_DTable *HUFptr;
  65. ZSTD_entropyTables_t entropy;
  66. const void *previousDstEnd; /* detect continuity */
  67. const void *base; /* start of curr segment */
  68. const void *vBase; /* virtual start of previous segment if it was just before curr one */
  69. const void *dictEnd; /* end of previous segment */
  70. size_t expected;
  71. ZSTD_frameParams fParams;
  72. blockType_e bType; /* used in ZSTD_decompressContinue(), to transfer blockType between header decoding and block decoding stages */
  73. ZSTD_dStage stage;
  74. U32 litEntropy;
  75. U32 fseEntropy;
  76. struct xxh64_state xxhState;
  77. size_t headerSize;
  78. U32 dictID;
  79. const BYTE *litPtr;
  80. ZSTD_customMem customMem;
  81. size_t litSize;
  82. size_t rleSize;
  83. BYTE litBuffer[ZSTD_BLOCKSIZE_ABSOLUTEMAX + WILDCOPY_OVERLENGTH];
  84. BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
  85. }; /* typedef'd to ZSTD_DCtx within "zstd.h" */
  86. size_t ZSTD_DCtxWorkspaceBound(void) { return ZSTD_ALIGN(sizeof(ZSTD_stack)) + ZSTD_ALIGN(sizeof(ZSTD_DCtx)); }
  87. size_t ZSTD_decompressBegin(ZSTD_DCtx *dctx)
  88. {
  89. dctx->expected = ZSTD_frameHeaderSize_prefix;
  90. dctx->stage = ZSTDds_getFrameHeaderSize;
  91. dctx->previousDstEnd = NULL;
  92. dctx->base = NULL;
  93. dctx->vBase = NULL;
  94. dctx->dictEnd = NULL;
  95. dctx->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); /* cover both little and big endian */
  96. dctx->litEntropy = dctx->fseEntropy = 0;
  97. dctx->dictID = 0;
  98. ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.rep) == sizeof(repStartValue));
  99. memcpy(dctx->entropy.rep, repStartValue, sizeof(repStartValue)); /* initial repcodes */
  100. dctx->LLTptr = dctx->entropy.LLTable;
  101. dctx->MLTptr = dctx->entropy.MLTable;
  102. dctx->OFTptr = dctx->entropy.OFTable;
  103. dctx->HUFptr = dctx->entropy.hufTable;
  104. return 0;
  105. }
  106. ZSTD_DCtx *ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
  107. {
  108. ZSTD_DCtx *dctx;
  109. if (!customMem.customAlloc || !customMem.customFree)
  110. return NULL;
  111. dctx = (ZSTD_DCtx *)ZSTD_malloc(sizeof(ZSTD_DCtx), customMem);
  112. if (!dctx)
  113. return NULL;
  114. memcpy(&dctx->customMem, &customMem, sizeof(customMem));
  115. ZSTD_decompressBegin(dctx);
  116. return dctx;
  117. }
  118. ZSTD_DCtx *ZSTD_initDCtx(void *workspace, size_t workspaceSize)
  119. {
  120. ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
  121. return ZSTD_createDCtx_advanced(stackMem);
  122. }
  123. size_t ZSTD_freeDCtx(ZSTD_DCtx *dctx)
  124. {
  125. if (dctx == NULL)
  126. return 0; /* support free on NULL */
  127. ZSTD_free(dctx, dctx->customMem);
  128. return 0; /* reserved as a potential error code in the future */
  129. }
  130. void ZSTD_copyDCtx(ZSTD_DCtx *dstDCtx, const ZSTD_DCtx *srcDCtx)
  131. {
  132. size_t const workSpaceSize = (ZSTD_BLOCKSIZE_ABSOLUTEMAX + WILDCOPY_OVERLENGTH) + ZSTD_frameHeaderSize_max;
  133. memcpy(dstDCtx, srcDCtx, sizeof(ZSTD_DCtx) - workSpaceSize); /* no need to copy workspace */
  134. }
  135. static void ZSTD_refDDict(ZSTD_DCtx *dstDCtx, const ZSTD_DDict *ddict);
  136. /*-*************************************************************
  137. * Decompression section
  138. ***************************************************************/
  139. /*! ZSTD_isFrame() :
  140. * Tells if the content of `buffer` starts with a valid Frame Identifier.
  141. * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0.
  142. * Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled.
  143. * Note 3 : Skippable Frame Identifiers are considered valid. */
  144. unsigned ZSTD_isFrame(const void *buffer, size_t size)
  145. {
  146. if (size < 4)
  147. return 0;
  148. {
  149. U32 const magic = ZSTD_readLE32(buffer);
  150. if (magic == ZSTD_MAGICNUMBER)
  151. return 1;
  152. if ((magic & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START)
  153. return 1;
  154. }
  155. return 0;
  156. }
  157. /** ZSTD_frameHeaderSize() :
  158. * srcSize must be >= ZSTD_frameHeaderSize_prefix.
  159. * @return : size of the Frame Header */
  160. static size_t ZSTD_frameHeaderSize(const void *src, size_t srcSize)
  161. {
  162. if (srcSize < ZSTD_frameHeaderSize_prefix)
  163. return ERROR(srcSize_wrong);
  164. {
  165. BYTE const fhd = ((const BYTE *)src)[4];
  166. U32 const dictID = fhd & 3;
  167. U32 const singleSegment = (fhd >> 5) & 1;
  168. U32 const fcsId = fhd >> 6;
  169. return ZSTD_frameHeaderSize_prefix + !singleSegment + ZSTD_did_fieldSize[dictID] + ZSTD_fcs_fieldSize[fcsId] + (singleSegment && !fcsId);
  170. }
  171. }
  172. /** ZSTD_getFrameParams() :
  173. * decode Frame Header, or require larger `srcSize`.
  174. * @return : 0, `fparamsPtr` is correctly filled,
  175. * >0, `srcSize` is too small, result is expected `srcSize`,
  176. * or an error code, which can be tested using ZSTD_isError() */
  177. size_t ZSTD_getFrameParams(ZSTD_frameParams *fparamsPtr, const void *src, size_t srcSize)
  178. {
  179. const BYTE *ip = (const BYTE *)src;
  180. if (srcSize < ZSTD_frameHeaderSize_prefix)
  181. return ZSTD_frameHeaderSize_prefix;
  182. if (ZSTD_readLE32(src) != ZSTD_MAGICNUMBER) {
  183. if ((ZSTD_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
  184. if (srcSize < ZSTD_skippableHeaderSize)
  185. return ZSTD_skippableHeaderSize; /* magic number + skippable frame length */
  186. memset(fparamsPtr, 0, sizeof(*fparamsPtr));
  187. fparamsPtr->frameContentSize = ZSTD_readLE32((const char *)src + 4);
  188. fparamsPtr->windowSize = 0; /* windowSize==0 means a frame is skippable */
  189. return 0;
  190. }
  191. return ERROR(prefix_unknown);
  192. }
  193. /* ensure there is enough `srcSize` to fully read/decode frame header */
  194. {
  195. size_t const fhsize = ZSTD_frameHeaderSize(src, srcSize);
  196. if (srcSize < fhsize)
  197. return fhsize;
  198. }
  199. {
  200. BYTE const fhdByte = ip[4];
  201. size_t pos = 5;
  202. U32 const dictIDSizeCode = fhdByte & 3;
  203. U32 const checksumFlag = (fhdByte >> 2) & 1;
  204. U32 const singleSegment = (fhdByte >> 5) & 1;
  205. U32 const fcsID = fhdByte >> 6;
  206. U32 const windowSizeMax = 1U << ZSTD_WINDOWLOG_MAX;
  207. U32 windowSize = 0;
  208. U32 dictID = 0;
  209. U64 frameContentSize = 0;
  210. if ((fhdByte & 0x08) != 0)
  211. return ERROR(frameParameter_unsupported); /* reserved bits, which must be zero */
  212. if (!singleSegment) {
  213. BYTE const wlByte = ip[pos++];
  214. U32 const windowLog = (wlByte >> 3) + ZSTD_WINDOWLOG_ABSOLUTEMIN;
  215. if (windowLog > ZSTD_WINDOWLOG_MAX)
  216. return ERROR(frameParameter_windowTooLarge); /* avoids issue with 1 << windowLog */
  217. windowSize = (1U << windowLog);
  218. windowSize += (windowSize >> 3) * (wlByte & 7);
  219. }
  220. switch (dictIDSizeCode) {
  221. default: /* impossible */
  222. case 0: break;
  223. case 1:
  224. dictID = ip[pos];
  225. pos++;
  226. break;
  227. case 2:
  228. dictID = ZSTD_readLE16(ip + pos);
  229. pos += 2;
  230. break;
  231. case 3:
  232. dictID = ZSTD_readLE32(ip + pos);
  233. pos += 4;
  234. break;
  235. }
  236. switch (fcsID) {
  237. default: /* impossible */
  238. case 0:
  239. if (singleSegment)
  240. frameContentSize = ip[pos];
  241. break;
  242. case 1: frameContentSize = ZSTD_readLE16(ip + pos) + 256; break;
  243. case 2: frameContentSize = ZSTD_readLE32(ip + pos); break;
  244. case 3: frameContentSize = ZSTD_readLE64(ip + pos); break;
  245. }
  246. if (!windowSize)
  247. windowSize = (U32)frameContentSize;
  248. if (windowSize > windowSizeMax)
  249. return ERROR(frameParameter_windowTooLarge);
  250. fparamsPtr->frameContentSize = frameContentSize;
  251. fparamsPtr->windowSize = windowSize;
  252. fparamsPtr->dictID = dictID;
  253. fparamsPtr->checksumFlag = checksumFlag;
  254. }
  255. return 0;
  256. }
  257. /** ZSTD_getFrameContentSize() :
  258. * compatible with legacy mode
  259. * @return : decompressed size of the single frame pointed to be `src` if known, otherwise
  260. * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
  261. * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) */
  262. unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize)
  263. {
  264. {
  265. ZSTD_frameParams fParams;
  266. if (ZSTD_getFrameParams(&fParams, src, srcSize) != 0)
  267. return ZSTD_CONTENTSIZE_ERROR;
  268. if (fParams.windowSize == 0) {
  269. /* Either skippable or empty frame, size == 0 either way */
  270. return 0;
  271. } else if (fParams.frameContentSize != 0) {
  272. return fParams.frameContentSize;
  273. } else {
  274. return ZSTD_CONTENTSIZE_UNKNOWN;
  275. }
  276. }
  277. }
  278. /** ZSTD_findDecompressedSize() :
  279. * compatible with legacy mode
  280. * `srcSize` must be the exact length of some number of ZSTD compressed and/or
  281. * skippable frames
  282. * @return : decompressed size of the frames contained */
  283. unsigned long long ZSTD_findDecompressedSize(const void *src, size_t srcSize)
  284. {
  285. {
  286. unsigned long long totalDstSize = 0;
  287. while (srcSize >= ZSTD_frameHeaderSize_prefix) {
  288. const U32 magicNumber = ZSTD_readLE32(src);
  289. if ((magicNumber & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
  290. size_t skippableSize;
  291. if (srcSize < ZSTD_skippableHeaderSize)
  292. return ERROR(srcSize_wrong);
  293. skippableSize = ZSTD_readLE32((const BYTE *)src + 4) + ZSTD_skippableHeaderSize;
  294. if (srcSize < skippableSize) {
  295. return ZSTD_CONTENTSIZE_ERROR;
  296. }
  297. src = (const BYTE *)src + skippableSize;
  298. srcSize -= skippableSize;
  299. continue;
  300. }
  301. {
  302. unsigned long long const ret = ZSTD_getFrameContentSize(src, srcSize);
  303. if (ret >= ZSTD_CONTENTSIZE_ERROR)
  304. return ret;
  305. /* check for overflow */
  306. if (totalDstSize + ret < totalDstSize)
  307. return ZSTD_CONTENTSIZE_ERROR;
  308. totalDstSize += ret;
  309. }
  310. {
  311. size_t const frameSrcSize = ZSTD_findFrameCompressedSize(src, srcSize);
  312. if (ZSTD_isError(frameSrcSize)) {
  313. return ZSTD_CONTENTSIZE_ERROR;
  314. }
  315. src = (const BYTE *)src + frameSrcSize;
  316. srcSize -= frameSrcSize;
  317. }
  318. }
  319. if (srcSize) {
  320. return ZSTD_CONTENTSIZE_ERROR;
  321. }
  322. return totalDstSize;
  323. }
  324. }
  325. /** ZSTD_decodeFrameHeader() :
  326. * `headerSize` must be the size provided by ZSTD_frameHeaderSize().
  327. * @return : 0 if success, or an error code, which can be tested using ZSTD_isError() */
  328. static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx *dctx, const void *src, size_t headerSize)
  329. {
  330. size_t const result = ZSTD_getFrameParams(&(dctx->fParams), src, headerSize);
  331. if (ZSTD_isError(result))
  332. return result; /* invalid header */
  333. if (result > 0)
  334. return ERROR(srcSize_wrong); /* headerSize too small */
  335. if (dctx->fParams.dictID && (dctx->dictID != dctx->fParams.dictID))
  336. return ERROR(dictionary_wrong);
  337. if (dctx->fParams.checksumFlag)
  338. xxh64_reset(&dctx->xxhState, 0);
  339. return 0;
  340. }
  341. typedef struct {
  342. blockType_e blockType;
  343. U32 lastBlock;
  344. U32 origSize;
  345. } blockProperties_t;
  346. /*! ZSTD_getcBlockSize() :
  347. * Provides the size of compressed block from block header `src` */
  348. size_t ZSTD_getcBlockSize(const void *src, size_t srcSize, blockProperties_t *bpPtr)
  349. {
  350. if (srcSize < ZSTD_blockHeaderSize)
  351. return ERROR(srcSize_wrong);
  352. {
  353. U32 const cBlockHeader = ZSTD_readLE24(src);
  354. U32 const cSize = cBlockHeader >> 3;
  355. bpPtr->lastBlock = cBlockHeader & 1;
  356. bpPtr->blockType = (blockType_e)((cBlockHeader >> 1) & 3);
  357. bpPtr->origSize = cSize; /* only useful for RLE */
  358. if (bpPtr->blockType == bt_rle)
  359. return 1;
  360. if (bpPtr->blockType == bt_reserved)
  361. return ERROR(corruption_detected);
  362. return cSize;
  363. }
  364. }
  365. static size_t ZSTD_copyRawBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
  366. {
  367. if (srcSize > dstCapacity)
  368. return ERROR(dstSize_tooSmall);
  369. memcpy(dst, src, srcSize);
  370. return srcSize;
  371. }
  372. static size_t ZSTD_setRleBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize, size_t regenSize)
  373. {
  374. if (srcSize != 1)
  375. return ERROR(srcSize_wrong);
  376. if (regenSize > dstCapacity)
  377. return ERROR(dstSize_tooSmall);
  378. memset(dst, *(const BYTE *)src, regenSize);
  379. return regenSize;
  380. }
  381. /*! ZSTD_decodeLiteralsBlock() :
  382. @return : nb of bytes read from src (< srcSize ) */
  383. size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx *dctx, const void *src, size_t srcSize) /* note : srcSize < BLOCKSIZE */
  384. {
  385. if (srcSize < MIN_CBLOCK_SIZE)
  386. return ERROR(corruption_detected);
  387. {
  388. const BYTE *const istart = (const BYTE *)src;
  389. symbolEncodingType_e const litEncType = (symbolEncodingType_e)(istart[0] & 3);
  390. switch (litEncType) {
  391. case set_repeat:
  392. if (dctx->litEntropy == 0)
  393. return ERROR(dictionary_corrupted);
  394. /* fall-through */
  395. case set_compressed:
  396. if (srcSize < 5)
  397. return ERROR(corruption_detected); /* srcSize >= MIN_CBLOCK_SIZE == 3; here we need up to 5 for case 3 */
  398. {
  399. size_t lhSize, litSize, litCSize;
  400. U32 singleStream = 0;
  401. U32 const lhlCode = (istart[0] >> 2) & 3;
  402. U32 const lhc = ZSTD_readLE32(istart);
  403. switch (lhlCode) {
  404. case 0:
  405. case 1:
  406. default: /* note : default is impossible, since lhlCode into [0..3] */
  407. /* 2 - 2 - 10 - 10 */
  408. singleStream = !lhlCode;
  409. lhSize = 3;
  410. litSize = (lhc >> 4) & 0x3FF;
  411. litCSize = (lhc >> 14) & 0x3FF;
  412. break;
  413. case 2:
  414. /* 2 - 2 - 14 - 14 */
  415. lhSize = 4;
  416. litSize = (lhc >> 4) & 0x3FFF;
  417. litCSize = lhc >> 18;
  418. break;
  419. case 3:
  420. /* 2 - 2 - 18 - 18 */
  421. lhSize = 5;
  422. litSize = (lhc >> 4) & 0x3FFFF;
  423. litCSize = (lhc >> 22) + (istart[4] << 10);
  424. break;
  425. }
  426. if (litSize > ZSTD_BLOCKSIZE_ABSOLUTEMAX)
  427. return ERROR(corruption_detected);
  428. if (litCSize + lhSize > srcSize)
  429. return ERROR(corruption_detected);
  430. if (HUF_isError(
  431. (litEncType == set_repeat)
  432. ? (singleStream ? HUF_decompress1X_usingDTable(dctx->litBuffer, litSize, istart + lhSize, litCSize, dctx->HUFptr)
  433. : HUF_decompress4X_usingDTable(dctx->litBuffer, litSize, istart + lhSize, litCSize, dctx->HUFptr))
  434. : (singleStream
  435. ? HUF_decompress1X2_DCtx_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, istart + lhSize, litCSize,
  436. dctx->entropy.workspace, sizeof(dctx->entropy.workspace))
  437. : HUF_decompress4X_hufOnly_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, istart + lhSize, litCSize,
  438. dctx->entropy.workspace, sizeof(dctx->entropy.workspace)))))
  439. return ERROR(corruption_detected);
  440. dctx->litPtr = dctx->litBuffer;
  441. dctx->litSize = litSize;
  442. dctx->litEntropy = 1;
  443. if (litEncType == set_compressed)
  444. dctx->HUFptr = dctx->entropy.hufTable;
  445. memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
  446. return litCSize + lhSize;
  447. }
  448. case set_basic: {
  449. size_t litSize, lhSize;
  450. U32 const lhlCode = ((istart[0]) >> 2) & 3;
  451. switch (lhlCode) {
  452. case 0:
  453. case 2:
  454. default: /* note : default is impossible, since lhlCode into [0..3] */
  455. lhSize = 1;
  456. litSize = istart[0] >> 3;
  457. break;
  458. case 1:
  459. lhSize = 2;
  460. litSize = ZSTD_readLE16(istart) >> 4;
  461. break;
  462. case 3:
  463. lhSize = 3;
  464. litSize = ZSTD_readLE24(istart) >> 4;
  465. break;
  466. }
  467. if (lhSize + litSize + WILDCOPY_OVERLENGTH > srcSize) { /* risk reading beyond src buffer with wildcopy */
  468. if (litSize + lhSize > srcSize)
  469. return ERROR(corruption_detected);
  470. memcpy(dctx->litBuffer, istart + lhSize, litSize);
  471. dctx->litPtr = dctx->litBuffer;
  472. dctx->litSize = litSize;
  473. memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
  474. return lhSize + litSize;
  475. }
  476. /* direct reference into compressed stream */
  477. dctx->litPtr = istart + lhSize;
  478. dctx->litSize = litSize;
  479. return lhSize + litSize;
  480. }
  481. case set_rle: {
  482. U32 const lhlCode = ((istart[0]) >> 2) & 3;
  483. size_t litSize, lhSize;
  484. switch (lhlCode) {
  485. case 0:
  486. case 2:
  487. default: /* note : default is impossible, since lhlCode into [0..3] */
  488. lhSize = 1;
  489. litSize = istart[0] >> 3;
  490. break;
  491. case 1:
  492. lhSize = 2;
  493. litSize = ZSTD_readLE16(istart) >> 4;
  494. break;
  495. case 3:
  496. lhSize = 3;
  497. litSize = ZSTD_readLE24(istart) >> 4;
  498. if (srcSize < 4)
  499. return ERROR(corruption_detected); /* srcSize >= MIN_CBLOCK_SIZE == 3; here we need lhSize+1 = 4 */
  500. break;
  501. }
  502. if (litSize > ZSTD_BLOCKSIZE_ABSOLUTEMAX)
  503. return ERROR(corruption_detected);
  504. memset(dctx->litBuffer, istart[lhSize], litSize + WILDCOPY_OVERLENGTH);
  505. dctx->litPtr = dctx->litBuffer;
  506. dctx->litSize = litSize;
  507. return lhSize + 1;
  508. }
  509. default:
  510. return ERROR(corruption_detected); /* impossible */
  511. }
  512. }
  513. }
  514. typedef union {
  515. FSE_decode_t realData;
  516. U32 alignedBy4;
  517. } FSE_decode_t4;
  518. static const FSE_decode_t4 LL_defaultDTable[(1 << LL_DEFAULTNORMLOG) + 1] = {
  519. {{LL_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
  520. {{0, 0, 4}}, /* 0 : base, symbol, bits */
  521. {{16, 0, 4}},
  522. {{32, 1, 5}},
  523. {{0, 3, 5}},
  524. {{0, 4, 5}},
  525. {{0, 6, 5}},
  526. {{0, 7, 5}},
  527. {{0, 9, 5}},
  528. {{0, 10, 5}},
  529. {{0, 12, 5}},
  530. {{0, 14, 6}},
  531. {{0, 16, 5}},
  532. {{0, 18, 5}},
  533. {{0, 19, 5}},
  534. {{0, 21, 5}},
  535. {{0, 22, 5}},
  536. {{0, 24, 5}},
  537. {{32, 25, 5}},
  538. {{0, 26, 5}},
  539. {{0, 27, 6}},
  540. {{0, 29, 6}},
  541. {{0, 31, 6}},
  542. {{32, 0, 4}},
  543. {{0, 1, 4}},
  544. {{0, 2, 5}},
  545. {{32, 4, 5}},
  546. {{0, 5, 5}},
  547. {{32, 7, 5}},
  548. {{0, 8, 5}},
  549. {{32, 10, 5}},
  550. {{0, 11, 5}},
  551. {{0, 13, 6}},
  552. {{32, 16, 5}},
  553. {{0, 17, 5}},
  554. {{32, 19, 5}},
  555. {{0, 20, 5}},
  556. {{32, 22, 5}},
  557. {{0, 23, 5}},
  558. {{0, 25, 4}},
  559. {{16, 25, 4}},
  560. {{32, 26, 5}},
  561. {{0, 28, 6}},
  562. {{0, 30, 6}},
  563. {{48, 0, 4}},
  564. {{16, 1, 4}},
  565. {{32, 2, 5}},
  566. {{32, 3, 5}},
  567. {{32, 5, 5}},
  568. {{32, 6, 5}},
  569. {{32, 8, 5}},
  570. {{32, 9, 5}},
  571. {{32, 11, 5}},
  572. {{32, 12, 5}},
  573. {{0, 15, 6}},
  574. {{32, 17, 5}},
  575. {{32, 18, 5}},
  576. {{32, 20, 5}},
  577. {{32, 21, 5}},
  578. {{32, 23, 5}},
  579. {{32, 24, 5}},
  580. {{0, 35, 6}},
  581. {{0, 34, 6}},
  582. {{0, 33, 6}},
  583. {{0, 32, 6}},
  584. }; /* LL_defaultDTable */
  585. static const FSE_decode_t4 ML_defaultDTable[(1 << ML_DEFAULTNORMLOG) + 1] = {
  586. {{ML_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
  587. {{0, 0, 6}}, /* 0 : base, symbol, bits */
  588. {{0, 1, 4}},
  589. {{32, 2, 5}},
  590. {{0, 3, 5}},
  591. {{0, 5, 5}},
  592. {{0, 6, 5}},
  593. {{0, 8, 5}},
  594. {{0, 10, 6}},
  595. {{0, 13, 6}},
  596. {{0, 16, 6}},
  597. {{0, 19, 6}},
  598. {{0, 22, 6}},
  599. {{0, 25, 6}},
  600. {{0, 28, 6}},
  601. {{0, 31, 6}},
  602. {{0, 33, 6}},
  603. {{0, 35, 6}},
  604. {{0, 37, 6}},
  605. {{0, 39, 6}},
  606. {{0, 41, 6}},
  607. {{0, 43, 6}},
  608. {{0, 45, 6}},
  609. {{16, 1, 4}},
  610. {{0, 2, 4}},
  611. {{32, 3, 5}},
  612. {{0, 4, 5}},
  613. {{32, 6, 5}},
  614. {{0, 7, 5}},
  615. {{0, 9, 6}},
  616. {{0, 12, 6}},
  617. {{0, 15, 6}},
  618. {{0, 18, 6}},
  619. {{0, 21, 6}},
  620. {{0, 24, 6}},
  621. {{0, 27, 6}},
  622. {{0, 30, 6}},
  623. {{0, 32, 6}},
  624. {{0, 34, 6}},
  625. {{0, 36, 6}},
  626. {{0, 38, 6}},
  627. {{0, 40, 6}},
  628. {{0, 42, 6}},
  629. {{0, 44, 6}},
  630. {{32, 1, 4}},
  631. {{48, 1, 4}},
  632. {{16, 2, 4}},
  633. {{32, 4, 5}},
  634. {{32, 5, 5}},
  635. {{32, 7, 5}},
  636. {{32, 8, 5}},
  637. {{0, 11, 6}},
  638. {{0, 14, 6}},
  639. {{0, 17, 6}},
  640. {{0, 20, 6}},
  641. {{0, 23, 6}},
  642. {{0, 26, 6}},
  643. {{0, 29, 6}},
  644. {{0, 52, 6}},
  645. {{0, 51, 6}},
  646. {{0, 50, 6}},
  647. {{0, 49, 6}},
  648. {{0, 48, 6}},
  649. {{0, 47, 6}},
  650. {{0, 46, 6}},
  651. }; /* ML_defaultDTable */
  652. static const FSE_decode_t4 OF_defaultDTable[(1 << OF_DEFAULTNORMLOG) + 1] = {
  653. {{OF_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
  654. {{0, 0, 5}}, /* 0 : base, symbol, bits */
  655. {{0, 6, 4}},
  656. {{0, 9, 5}},
  657. {{0, 15, 5}},
  658. {{0, 21, 5}},
  659. {{0, 3, 5}},
  660. {{0, 7, 4}},
  661. {{0, 12, 5}},
  662. {{0, 18, 5}},
  663. {{0, 23, 5}},
  664. {{0, 5, 5}},
  665. {{0, 8, 4}},
  666. {{0, 14, 5}},
  667. {{0, 20, 5}},
  668. {{0, 2, 5}},
  669. {{16, 7, 4}},
  670. {{0, 11, 5}},
  671. {{0, 17, 5}},
  672. {{0, 22, 5}},
  673. {{0, 4, 5}},
  674. {{16, 8, 4}},
  675. {{0, 13, 5}},
  676. {{0, 19, 5}},
  677. {{0, 1, 5}},
  678. {{16, 6, 4}},
  679. {{0, 10, 5}},
  680. {{0, 16, 5}},
  681. {{0, 28, 5}},
  682. {{0, 27, 5}},
  683. {{0, 26, 5}},
  684. {{0, 25, 5}},
  685. {{0, 24, 5}},
  686. }; /* OF_defaultDTable */
  687. /*! ZSTD_buildSeqTable() :
  688. @return : nb bytes read from src,
  689. or an error code if it fails, testable with ZSTD_isError()
  690. */
  691. static size_t ZSTD_buildSeqTable(FSE_DTable *DTableSpace, const FSE_DTable **DTablePtr, symbolEncodingType_e type, U32 max, U32 maxLog, const void *src,
  692. size_t srcSize, const FSE_decode_t4 *defaultTable, U32 flagRepeatTable, void *workspace, size_t workspaceSize)
  693. {
  694. const void *const tmpPtr = defaultTable; /* bypass strict aliasing */
  695. switch (type) {
  696. case set_rle:
  697. if (!srcSize)
  698. return ERROR(srcSize_wrong);
  699. if ((*(const BYTE *)src) > max)
  700. return ERROR(corruption_detected);
  701. FSE_buildDTable_rle(DTableSpace, *(const BYTE *)src);
  702. *DTablePtr = DTableSpace;
  703. return 1;
  704. case set_basic: *DTablePtr = (const FSE_DTable *)tmpPtr; return 0;
  705. case set_repeat:
  706. if (!flagRepeatTable)
  707. return ERROR(corruption_detected);
  708. return 0;
  709. default: /* impossible */
  710. case set_compressed: {
  711. U32 tableLog;
  712. S16 *norm = (S16 *)workspace;
  713. size_t const spaceUsed32 = ALIGN(sizeof(S16) * (MaxSeq + 1), sizeof(U32)) >> 2;
  714. if ((spaceUsed32 << 2) > workspaceSize)
  715. return ERROR(GENERIC);
  716. workspace = (U32 *)workspace + spaceUsed32;
  717. workspaceSize -= (spaceUsed32 << 2);
  718. {
  719. size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize);
  720. if (FSE_isError(headerSize))
  721. return ERROR(corruption_detected);
  722. if (tableLog > maxLog)
  723. return ERROR(corruption_detected);
  724. FSE_buildDTable_wksp(DTableSpace, norm, max, tableLog, workspace, workspaceSize);
  725. *DTablePtr = DTableSpace;
  726. return headerSize;
  727. }
  728. }
  729. }
  730. }
  731. size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx *dctx, int *nbSeqPtr, const void *src, size_t srcSize)
  732. {
  733. const BYTE *const istart = (const BYTE *const)src;
  734. const BYTE *const iend = istart + srcSize;
  735. const BYTE *ip = istart;
  736. /* check */
  737. if (srcSize < MIN_SEQUENCES_SIZE)
  738. return ERROR(srcSize_wrong);
  739. /* SeqHead */
  740. {
  741. int nbSeq = *ip++;
  742. if (!nbSeq) {
  743. *nbSeqPtr = 0;
  744. return 1;
  745. }
  746. if (nbSeq > 0x7F) {
  747. if (nbSeq == 0xFF) {
  748. if (ip + 2 > iend)
  749. return ERROR(srcSize_wrong);
  750. nbSeq = ZSTD_readLE16(ip) + LONGNBSEQ, ip += 2;
  751. } else {
  752. if (ip >= iend)
  753. return ERROR(srcSize_wrong);
  754. nbSeq = ((nbSeq - 0x80) << 8) + *ip++;
  755. }
  756. }
  757. *nbSeqPtr = nbSeq;
  758. }
  759. /* FSE table descriptors */
  760. if (ip + 4 > iend)
  761. return ERROR(srcSize_wrong); /* minimum possible size */
  762. {
  763. symbolEncodingType_e const LLtype = (symbolEncodingType_e)(*ip >> 6);
  764. symbolEncodingType_e const OFtype = (symbolEncodingType_e)((*ip >> 4) & 3);
  765. symbolEncodingType_e const MLtype = (symbolEncodingType_e)((*ip >> 2) & 3);
  766. ip++;
  767. /* Build DTables */
  768. {
  769. size_t const llhSize = ZSTD_buildSeqTable(dctx->entropy.LLTable, &dctx->LLTptr, LLtype, MaxLL, LLFSELog, ip, iend - ip,
  770. LL_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, sizeof(dctx->entropy.workspace));
  771. if (ZSTD_isError(llhSize))
  772. return ERROR(corruption_detected);
  773. ip += llhSize;
  774. }
  775. {
  776. size_t const ofhSize = ZSTD_buildSeqTable(dctx->entropy.OFTable, &dctx->OFTptr, OFtype, MaxOff, OffFSELog, ip, iend - ip,
  777. OF_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, sizeof(dctx->entropy.workspace));
  778. if (ZSTD_isError(ofhSize))
  779. return ERROR(corruption_detected);
  780. ip += ofhSize;
  781. }
  782. {
  783. size_t const mlhSize = ZSTD_buildSeqTable(dctx->entropy.MLTable, &dctx->MLTptr, MLtype, MaxML, MLFSELog, ip, iend - ip,
  784. ML_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, sizeof(dctx->entropy.workspace));
  785. if (ZSTD_isError(mlhSize))
  786. return ERROR(corruption_detected);
  787. ip += mlhSize;
  788. }
  789. }
  790. return ip - istart;
  791. }
  792. typedef struct {
  793. size_t litLength;
  794. size_t matchLength;
  795. size_t offset;
  796. const BYTE *match;
  797. } seq_t;
  798. typedef struct {
  799. BIT_DStream_t DStream;
  800. FSE_DState_t stateLL;
  801. FSE_DState_t stateOffb;
  802. FSE_DState_t stateML;
  803. size_t prevOffset[ZSTD_REP_NUM];
  804. const BYTE *base;
  805. size_t pos;
  806. uPtrDiff gotoDict;
  807. } seqState_t;
  808. FORCE_NOINLINE
  809. size_t ZSTD_execSequenceLast7(BYTE *op, BYTE *const oend, seq_t sequence, const BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
  810. const BYTE *const vBase, const BYTE *const dictEnd)
  811. {
  812. BYTE *const oLitEnd = op + sequence.litLength;
  813. size_t const sequenceLength = sequence.litLength + sequence.matchLength;
  814. BYTE *const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
  815. BYTE *const oend_w = oend - WILDCOPY_OVERLENGTH;
  816. const BYTE *const iLitEnd = *litPtr + sequence.litLength;
  817. const BYTE *match = oLitEnd - sequence.offset;
  818. /* check */
  819. if (oMatchEnd > oend)
  820. return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
  821. if (iLitEnd > litLimit)
  822. return ERROR(corruption_detected); /* over-read beyond lit buffer */
  823. if (oLitEnd <= oend_w)
  824. return ERROR(GENERIC); /* Precondition */
  825. /* copy literals */
  826. if (op < oend_w) {
  827. ZSTD_wildcopy(op, *litPtr, oend_w - op);
  828. *litPtr += oend_w - op;
  829. op = oend_w;
  830. }
  831. while (op < oLitEnd)
  832. *op++ = *(*litPtr)++;
  833. /* copy Match */
  834. if (sequence.offset > (size_t)(oLitEnd - base)) {
  835. /* offset beyond prefix */
  836. if (sequence.offset > (size_t)(oLitEnd - vBase))
  837. return ERROR(corruption_detected);
  838. match = dictEnd - (base - match);
  839. if (match + sequence.matchLength <= dictEnd) {
  840. memmove(oLitEnd, match, sequence.matchLength);
  841. return sequenceLength;
  842. }
  843. /* span extDict & currPrefixSegment */
  844. {
  845. size_t const length1 = dictEnd - match;
  846. memmove(oLitEnd, match, length1);
  847. op = oLitEnd + length1;
  848. sequence.matchLength -= length1;
  849. match = base;
  850. }
  851. }
  852. while (op < oMatchEnd)
  853. *op++ = *match++;
  854. return sequenceLength;
  855. }
  856. static seq_t ZSTD_decodeSequence(seqState_t *seqState)
  857. {
  858. seq_t seq;
  859. U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
  860. U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
  861. U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= maxOff, by table construction */
  862. U32 const llBits = LL_bits[llCode];
  863. U32 const mlBits = ML_bits[mlCode];
  864. U32 const ofBits = ofCode;
  865. U32 const totalBits = llBits + mlBits + ofBits;
  866. static const U32 LL_base[MaxLL + 1] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18,
  867. 20, 22, 24, 28, 32, 40, 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000};
  868. static const U32 ML_base[MaxML + 1] = {3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
  869. 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 39, 41,
  870. 43, 47, 51, 59, 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803, 0x1003, 0x2003, 0x4003, 0x8003, 0x10003};
  871. static const U32 OF_base[MaxOff + 1] = {0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D, 0xFD, 0x1FD,
  872. 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD, 0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD,
  873. 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD, 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD};
  874. /* sequence */
  875. {
  876. size_t offset;
  877. if (!ofCode)
  878. offset = 0;
  879. else {
  880. offset = OF_base[ofCode] + BIT_readBitsFast(&seqState->DStream, ofBits); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */
  881. if (ZSTD_32bits())
  882. BIT_reloadDStream(&seqState->DStream);
  883. }
  884. if (ofCode <= 1) {
  885. offset += (llCode == 0);
  886. if (offset) {
  887. size_t temp = (offset == 3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
  888. temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */
  889. if (offset != 1)
  890. seqState->prevOffset[2] = seqState->prevOffset[1];
  891. seqState->prevOffset[1] = seqState->prevOffset[0];
  892. seqState->prevOffset[0] = offset = temp;
  893. } else {
  894. offset = seqState->prevOffset[0];
  895. }
  896. } else {
  897. seqState->prevOffset[2] = seqState->prevOffset[1];
  898. seqState->prevOffset[1] = seqState->prevOffset[0];
  899. seqState->prevOffset[0] = offset;
  900. }
  901. seq.offset = offset;
  902. }
  903. seq.matchLength = ML_base[mlCode] + ((mlCode > 31) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <= 16 bits */
  904. if (ZSTD_32bits() && (mlBits + llBits > 24))
  905. BIT_reloadDStream(&seqState->DStream);
  906. seq.litLength = LL_base[llCode] + ((llCode > 15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <= 16 bits */
  907. if (ZSTD_32bits() || (totalBits > 64 - 7 - (LLFSELog + MLFSELog + OffFSELog)))
  908. BIT_reloadDStream(&seqState->DStream);
  909. /* ANS state update */
  910. FSE_updateState(&seqState->stateLL, &seqState->DStream); /* <= 9 bits */
  911. FSE_updateState(&seqState->stateML, &seqState->DStream); /* <= 9 bits */
  912. if (ZSTD_32bits())
  913. BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */
  914. FSE_updateState(&seqState->stateOffb, &seqState->DStream); /* <= 8 bits */
  915. seq.match = NULL;
  916. return seq;
  917. }
  918. FORCE_INLINE
  919. size_t ZSTD_execSequence(BYTE *op, BYTE *const oend, seq_t sequence, const BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
  920. const BYTE *const vBase, const BYTE *const dictEnd)
  921. {
  922. BYTE *const oLitEnd = op + sequence.litLength;
  923. size_t const sequenceLength = sequence.litLength + sequence.matchLength;
  924. BYTE *const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
  925. BYTE *const oend_w = oend - WILDCOPY_OVERLENGTH;
  926. const BYTE *const iLitEnd = *litPtr + sequence.litLength;
  927. const BYTE *match = oLitEnd - sequence.offset;
  928. /* check */
  929. if (oMatchEnd > oend)
  930. return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
  931. if (iLitEnd > litLimit)
  932. return ERROR(corruption_detected); /* over-read beyond lit buffer */
  933. if (oLitEnd > oend_w)
  934. return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, base, vBase, dictEnd);
  935. /* copy Literals */
  936. ZSTD_copy8(op, *litPtr);
  937. if (sequence.litLength > 8)
  938. ZSTD_wildcopy(op + 8, (*litPtr) + 8,
  939. sequence.litLength - 8); /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
  940. op = oLitEnd;
  941. *litPtr = iLitEnd; /* update for next sequence */
  942. /* copy Match */
  943. if (sequence.offset > (size_t)(oLitEnd - base)) {
  944. /* offset beyond prefix */
  945. if (sequence.offset > (size_t)(oLitEnd - vBase))
  946. return ERROR(corruption_detected);
  947. match = dictEnd + (match - base);
  948. if (match + sequence.matchLength <= dictEnd) {
  949. memmove(oLitEnd, match, sequence.matchLength);
  950. return sequenceLength;
  951. }
  952. /* span extDict & currPrefixSegment */
  953. {
  954. size_t const length1 = dictEnd - match;
  955. memmove(oLitEnd, match, length1);
  956. op = oLitEnd + length1;
  957. sequence.matchLength -= length1;
  958. match = base;
  959. if (op > oend_w || sequence.matchLength < MINMATCH) {
  960. U32 i;
  961. for (i = 0; i < sequence.matchLength; ++i)
  962. op[i] = match[i];
  963. return sequenceLength;
  964. }
  965. }
  966. }
  967. /* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
  968. /* match within prefix */
  969. if (sequence.offset < 8) {
  970. /* close range match, overlap */
  971. static const U32 dec32table[] = {0, 1, 2, 1, 4, 4, 4, 4}; /* added */
  972. static const int dec64table[] = {8, 8, 8, 7, 8, 9, 10, 11}; /* subtracted */
  973. int const sub2 = dec64table[sequence.offset];
  974. op[0] = match[0];
  975. op[1] = match[1];
  976. op[2] = match[2];
  977. op[3] = match[3];
  978. match += dec32table[sequence.offset];
  979. ZSTD_copy4(op + 4, match);
  980. match -= sub2;
  981. } else {
  982. ZSTD_copy8(op, match);
  983. }
  984. op += 8;
  985. match += 8;
  986. if (oMatchEnd > oend - (16 - MINMATCH)) {
  987. if (op < oend_w) {
  988. ZSTD_wildcopy(op, match, oend_w - op);
  989. match += oend_w - op;
  990. op = oend_w;
  991. }
  992. while (op < oMatchEnd)
  993. *op++ = *match++;
  994. } else {
  995. ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength - 8); /* works even if matchLength < 8 */
  996. }
  997. return sequenceLength;
  998. }
  999. static size_t ZSTD_decompressSequences(ZSTD_DCtx *dctx, void *dst, size_t maxDstSize, const void *seqStart, size_t seqSize)
  1000. {
  1001. const BYTE *ip = (const BYTE *)seqStart;
  1002. const BYTE *const iend = ip + seqSize;
  1003. BYTE *const ostart = (BYTE * const)dst;
  1004. BYTE *const oend = ostart + maxDstSize;
  1005. BYTE *op = ostart;
  1006. const BYTE *litPtr = dctx->litPtr;
  1007. const BYTE *const litEnd = litPtr + dctx->litSize;
  1008. const BYTE *const base = (const BYTE *)(dctx->base);
  1009. const BYTE *const vBase = (const BYTE *)(dctx->vBase);
  1010. const BYTE *const dictEnd = (const BYTE *)(dctx->dictEnd);
  1011. int nbSeq;
  1012. /* Build Decoding Tables */
  1013. {
  1014. size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, seqSize);
  1015. if (ZSTD_isError(seqHSize))
  1016. return seqHSize;
  1017. ip += seqHSize;
  1018. }
  1019. /* Regen sequences */
  1020. if (nbSeq) {
  1021. seqState_t seqState;
  1022. dctx->fseEntropy = 1;
  1023. {
  1024. U32 i;
  1025. for (i = 0; i < ZSTD_REP_NUM; i++)
  1026. seqState.prevOffset[i] = dctx->entropy.rep[i];
  1027. }
  1028. CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend - ip), corruption_detected);
  1029. FSE_initDState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
  1030. FSE_initDState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
  1031. FSE_initDState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
  1032. for (; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && nbSeq;) {
  1033. nbSeq--;
  1034. {
  1035. seq_t const sequence = ZSTD_decodeSequence(&seqState);
  1036. size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, base, vBase, dictEnd);
  1037. if (ZSTD_isError(oneSeqSize))
  1038. return oneSeqSize;
  1039. op += oneSeqSize;
  1040. }
  1041. }
  1042. /* check if reached exact end */
  1043. if (nbSeq)
  1044. return ERROR(corruption_detected);
  1045. /* save reps for next block */
  1046. {
  1047. U32 i;
  1048. for (i = 0; i < ZSTD_REP_NUM; i++)
  1049. dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]);
  1050. }
  1051. }
  1052. /* last literal segment */
  1053. {
  1054. size_t const lastLLSize = litEnd - litPtr;
  1055. if (lastLLSize > (size_t)(oend - op))
  1056. return ERROR(dstSize_tooSmall);
  1057. memcpy(op, litPtr, lastLLSize);
  1058. op += lastLLSize;
  1059. }
  1060. return op - ostart;
  1061. }
  1062. FORCE_INLINE seq_t ZSTD_decodeSequenceLong_generic(seqState_t *seqState, int const longOffsets)
  1063. {
  1064. seq_t seq;
  1065. U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
  1066. U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
  1067. U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= maxOff, by table construction */
  1068. U32 const llBits = LL_bits[llCode];
  1069. U32 const mlBits = ML_bits[mlCode];
  1070. U32 const ofBits = ofCode;
  1071. U32 const totalBits = llBits + mlBits + ofBits;
  1072. static const U32 LL_base[MaxLL + 1] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18,
  1073. 20, 22, 24, 28, 32, 40, 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000};
  1074. static const U32 ML_base[MaxML + 1] = {3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
  1075. 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 39, 41,
  1076. 43, 47, 51, 59, 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803, 0x1003, 0x2003, 0x4003, 0x8003, 0x10003};
  1077. static const U32 OF_base[MaxOff + 1] = {0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D, 0xFD, 0x1FD,
  1078. 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD, 0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD,
  1079. 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD, 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD};
  1080. /* sequence */
  1081. {
  1082. size_t offset;
  1083. if (!ofCode)
  1084. offset = 0;
  1085. else {
  1086. if (longOffsets) {
  1087. int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN);
  1088. offset = OF_base[ofCode] + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
  1089. if (ZSTD_32bits() || extraBits)
  1090. BIT_reloadDStream(&seqState->DStream);
  1091. if (extraBits)
  1092. offset += BIT_readBitsFast(&seqState->DStream, extraBits);
  1093. } else {
  1094. offset = OF_base[ofCode] + BIT_readBitsFast(&seqState->DStream, ofBits); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */
  1095. if (ZSTD_32bits())
  1096. BIT_reloadDStream(&seqState->DStream);
  1097. }
  1098. }
  1099. if (ofCode <= 1) {
  1100. offset += (llCode == 0);
  1101. if (offset) {
  1102. size_t temp = (offset == 3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
  1103. temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */
  1104. if (offset != 1)
  1105. seqState->prevOffset[2] = seqState->prevOffset[1];
  1106. seqState->prevOffset[1] = seqState->prevOffset[0];
  1107. seqState->prevOffset[0] = offset = temp;
  1108. } else {
  1109. offset = seqState->prevOffset[0];
  1110. }
  1111. } else {
  1112. seqState->prevOffset[2] = seqState->prevOffset[1];
  1113. seqState->prevOffset[1] = seqState->prevOffset[0];
  1114. seqState->prevOffset[0] = offset;
  1115. }
  1116. seq.offset = offset;
  1117. }
  1118. seq.matchLength = ML_base[mlCode] + ((mlCode > 31) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <= 16 bits */
  1119. if (ZSTD_32bits() && (mlBits + llBits > 24))
  1120. BIT_reloadDStream(&seqState->DStream);
  1121. seq.litLength = LL_base[llCode] + ((llCode > 15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <= 16 bits */
  1122. if (ZSTD_32bits() || (totalBits > 64 - 7 - (LLFSELog + MLFSELog + OffFSELog)))
  1123. BIT_reloadDStream(&seqState->DStream);
  1124. {
  1125. size_t const pos = seqState->pos + seq.litLength;
  1126. seq.match = seqState->base + pos - seq.offset; /* single memory segment */
  1127. if (seq.offset > pos)
  1128. seq.match += seqState->gotoDict; /* separate memory segment */
  1129. seqState->pos = pos + seq.matchLength;
  1130. }
  1131. /* ANS state update */
  1132. FSE_updateState(&seqState->stateLL, &seqState->DStream); /* <= 9 bits */
  1133. FSE_updateState(&seqState->stateML, &seqState->DStream); /* <= 9 bits */
  1134. if (ZSTD_32bits())
  1135. BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */
  1136. FSE_updateState(&seqState->stateOffb, &seqState->DStream); /* <= 8 bits */
  1137. return seq;
  1138. }
  1139. static seq_t ZSTD_decodeSequenceLong(seqState_t *seqState, unsigned const windowSize)
  1140. {
  1141. if (ZSTD_highbit32(windowSize) > STREAM_ACCUMULATOR_MIN) {
  1142. return ZSTD_decodeSequenceLong_generic(seqState, 1);
  1143. } else {
  1144. return ZSTD_decodeSequenceLong_generic(seqState, 0);
  1145. }
  1146. }
  1147. FORCE_INLINE
  1148. size_t ZSTD_execSequenceLong(BYTE *op, BYTE *const oend, seq_t sequence, const BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
  1149. const BYTE *const vBase, const BYTE *const dictEnd)
  1150. {
  1151. BYTE *const oLitEnd = op + sequence.litLength;
  1152. size_t const sequenceLength = sequence.litLength + sequence.matchLength;
  1153. BYTE *const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
  1154. BYTE *const oend_w = oend - WILDCOPY_OVERLENGTH;
  1155. const BYTE *const iLitEnd = *litPtr + sequence.litLength;
  1156. const BYTE *match = sequence.match;
  1157. /* check */
  1158. if (oMatchEnd > oend)
  1159. return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
  1160. if (iLitEnd > litLimit)
  1161. return ERROR(corruption_detected); /* over-read beyond lit buffer */
  1162. if (oLitEnd > oend_w)
  1163. return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, base, vBase, dictEnd);
  1164. /* copy Literals */
  1165. ZSTD_copy8(op, *litPtr);
  1166. if (sequence.litLength > 8)
  1167. ZSTD_wildcopy(op + 8, (*litPtr) + 8,
  1168. sequence.litLength - 8); /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
  1169. op = oLitEnd;
  1170. *litPtr = iLitEnd; /* update for next sequence */
  1171. /* copy Match */
  1172. if (sequence.offset > (size_t)(oLitEnd - base)) {
  1173. /* offset beyond prefix */
  1174. if (sequence.offset > (size_t)(oLitEnd - vBase))
  1175. return ERROR(corruption_detected);
  1176. if (match + sequence.matchLength <= dictEnd) {
  1177. memmove(oLitEnd, match, sequence.matchLength);
  1178. return sequenceLength;
  1179. }
  1180. /* span extDict & currPrefixSegment */
  1181. {
  1182. size_t const length1 = dictEnd - match;
  1183. memmove(oLitEnd, match, length1);
  1184. op = oLitEnd + length1;
  1185. sequence.matchLength -= length1;
  1186. match = base;
  1187. if (op > oend_w || sequence.matchLength < MINMATCH) {
  1188. U32 i;
  1189. for (i = 0; i < sequence.matchLength; ++i)
  1190. op[i] = match[i];
  1191. return sequenceLength;
  1192. }
  1193. }
  1194. }
  1195. /* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
  1196. /* match within prefix */
  1197. if (sequence.offset < 8) {
  1198. /* close range match, overlap */
  1199. static const U32 dec32table[] = {0, 1, 2, 1, 4, 4, 4, 4}; /* added */
  1200. static const int dec64table[] = {8, 8, 8, 7, 8, 9, 10, 11}; /* subtracted */
  1201. int const sub2 = dec64table[sequence.offset];
  1202. op[0] = match[0];
  1203. op[1] = match[1];
  1204. op[2] = match[2];
  1205. op[3] = match[3];
  1206. match += dec32table[sequence.offset];
  1207. ZSTD_copy4(op + 4, match);
  1208. match -= sub2;
  1209. } else {
  1210. ZSTD_copy8(op, match);
  1211. }
  1212. op += 8;
  1213. match += 8;
  1214. if (oMatchEnd > oend - (16 - MINMATCH)) {
  1215. if (op < oend_w) {
  1216. ZSTD_wildcopy(op, match, oend_w - op);
  1217. match += oend_w - op;
  1218. op = oend_w;
  1219. }
  1220. while (op < oMatchEnd)
  1221. *op++ = *match++;
  1222. } else {
  1223. ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength - 8); /* works even if matchLength < 8 */
  1224. }
  1225. return sequenceLength;
  1226. }
  1227. static size_t ZSTD_decompressSequencesLong(ZSTD_DCtx *dctx, void *dst, size_t maxDstSize, const void *seqStart, size_t seqSize)
  1228. {
  1229. const BYTE *ip = (const BYTE *)seqStart;
  1230. const BYTE *const iend = ip + seqSize;
  1231. BYTE *const ostart = (BYTE * const)dst;
  1232. BYTE *const oend = ostart + maxDstSize;
  1233. BYTE *op = ostart;
  1234. const BYTE *litPtr = dctx->litPtr;
  1235. const BYTE *const litEnd = litPtr + dctx->litSize;
  1236. const BYTE *const base = (const BYTE *)(dctx->base);
  1237. const BYTE *const vBase = (const BYTE *)(dctx->vBase);
  1238. const BYTE *const dictEnd = (const BYTE *)(dctx->dictEnd);
  1239. unsigned const windowSize = dctx->fParams.windowSize;
  1240. int nbSeq;
  1241. /* Build Decoding Tables */
  1242. {
  1243. size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, seqSize);
  1244. if (ZSTD_isError(seqHSize))
  1245. return seqHSize;
  1246. ip += seqHSize;
  1247. }
  1248. /* Regen sequences */
  1249. if (nbSeq) {
  1250. #define STORED_SEQS 4
  1251. #define STOSEQ_MASK (STORED_SEQS - 1)
  1252. #define ADVANCED_SEQS 4
  1253. seq_t *sequences = (seq_t *)dctx->entropy.workspace;
  1254. int const seqAdvance = MIN(nbSeq, ADVANCED_SEQS);
  1255. seqState_t seqState;
  1256. int seqNb;
  1257. ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.workspace) >= sizeof(seq_t) * STORED_SEQS);
  1258. dctx->fseEntropy = 1;
  1259. {
  1260. U32 i;
  1261. for (i = 0; i < ZSTD_REP_NUM; i++)
  1262. seqState.prevOffset[i] = dctx->entropy.rep[i];
  1263. }
  1264. seqState.base = base;
  1265. seqState.pos = (size_t)(op - base);
  1266. seqState.gotoDict = (uPtrDiff)dictEnd - (uPtrDiff)base; /* cast to avoid undefined behaviour */
  1267. CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend - ip), corruption_detected);
  1268. FSE_initDState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
  1269. FSE_initDState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
  1270. FSE_initDState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
  1271. /* prepare in advance */
  1272. for (seqNb = 0; (BIT_reloadDStream(&seqState.DStream) <= BIT_DStream_completed) && seqNb < seqAdvance; seqNb++) {
  1273. sequences[seqNb] = ZSTD_decodeSequenceLong(&seqState, windowSize);
  1274. }
  1275. if (seqNb < seqAdvance)
  1276. return ERROR(corruption_detected);
  1277. /* decode and decompress */
  1278. for (; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && seqNb < nbSeq; seqNb++) {
  1279. seq_t const sequence = ZSTD_decodeSequenceLong(&seqState, windowSize);
  1280. size_t const oneSeqSize =
  1281. ZSTD_execSequenceLong(op, oend, sequences[(seqNb - ADVANCED_SEQS) & STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
  1282. if (ZSTD_isError(oneSeqSize))
  1283. return oneSeqSize;
  1284. ZSTD_PREFETCH(sequence.match);
  1285. sequences[seqNb & STOSEQ_MASK] = sequence;
  1286. op += oneSeqSize;
  1287. }
  1288. if (seqNb < nbSeq)
  1289. return ERROR(corruption_detected);
  1290. /* finish queue */
  1291. seqNb -= seqAdvance;
  1292. for (; seqNb < nbSeq; seqNb++) {
  1293. size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[seqNb & STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
  1294. if (ZSTD_isError(oneSeqSize))
  1295. return oneSeqSize;
  1296. op += oneSeqSize;
  1297. }
  1298. /* save reps for next block */
  1299. {
  1300. U32 i;
  1301. for (i = 0; i < ZSTD_REP_NUM; i++)
  1302. dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]);
  1303. }
  1304. }
  1305. /* last literal segment */
  1306. {
  1307. size_t const lastLLSize = litEnd - litPtr;
  1308. if (lastLLSize > (size_t)(oend - op))
  1309. return ERROR(dstSize_tooSmall);
  1310. memcpy(op, litPtr, lastLLSize);
  1311. op += lastLLSize;
  1312. }
  1313. return op - ostart;
  1314. }
  1315. static size_t ZSTD_decompressBlock_internal(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
  1316. { /* blockType == blockCompressed */
  1317. const BYTE *ip = (const BYTE *)src;
  1318. if (srcSize >= ZSTD_BLOCKSIZE_ABSOLUTEMAX)
  1319. return ERROR(srcSize_wrong);
  1320. /* Decode literals section */
  1321. {
  1322. size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize);
  1323. if (ZSTD_isError(litCSize))
  1324. return litCSize;
  1325. ip += litCSize;
  1326. srcSize -= litCSize;
  1327. }
  1328. if (sizeof(size_t) > 4) /* do not enable prefetching on 32-bits x86, as it's performance detrimental */
  1329. /* likely because of register pressure */
  1330. /* if that's the correct cause, then 32-bits ARM should be affected differently */
  1331. /* it would be good to test this on ARM real hardware, to see if prefetch version improves speed */
  1332. if (dctx->fParams.windowSize > (1 << 23))
  1333. return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize);
  1334. return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize);
  1335. }
  1336. static void ZSTD_checkContinuity(ZSTD_DCtx *dctx, const void *dst)
  1337. {
  1338. if (dst != dctx->previousDstEnd) { /* not contiguous */
  1339. dctx->dictEnd = dctx->previousDstEnd;
  1340. dctx->vBase = (const char *)dst - ((const char *)(dctx->previousDstEnd) - (const char *)(dctx->base));
  1341. dctx->base = dst;
  1342. dctx->previousDstEnd = dst;
  1343. }
  1344. }
  1345. size_t ZSTD_decompressBlock(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
  1346. {
  1347. size_t dSize;
  1348. ZSTD_checkContinuity(dctx, dst);
  1349. dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize);
  1350. dctx->previousDstEnd = (char *)dst + dSize;
  1351. return dSize;
  1352. }
  1353. /** ZSTD_insertBlock() :
  1354. insert `src` block into `dctx` history. Useful to track uncompressed blocks. */
  1355. size_t ZSTD_insertBlock(ZSTD_DCtx *dctx, const void *blockStart, size_t blockSize)
  1356. {
  1357. ZSTD_checkContinuity(dctx, blockStart);
  1358. dctx->previousDstEnd = (const char *)blockStart + blockSize;
  1359. return blockSize;
  1360. }
  1361. size_t ZSTD_generateNxBytes(void *dst, size_t dstCapacity, BYTE byte, size_t length)
  1362. {
  1363. if (length > dstCapacity)
  1364. return ERROR(dstSize_tooSmall);
  1365. memset(dst, byte, length);
  1366. return length;
  1367. }
  1368. /** ZSTD_findFrameCompressedSize() :
  1369. * compatible with legacy mode
  1370. * `src` must point to the start of a ZSTD frame, ZSTD legacy frame, or skippable frame
  1371. * `srcSize` must be at least as large as the frame contained
  1372. * @return : the compressed size of the frame starting at `src` */
  1373. size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize)
  1374. {
  1375. if (srcSize >= ZSTD_skippableHeaderSize && (ZSTD_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
  1376. return ZSTD_skippableHeaderSize + ZSTD_readLE32((const BYTE *)src + 4);
  1377. } else {
  1378. const BYTE *ip = (const BYTE *)src;
  1379. const BYTE *const ipstart = ip;
  1380. size_t remainingSize = srcSize;
  1381. ZSTD_frameParams fParams;
  1382. size_t const headerSize = ZSTD_frameHeaderSize(ip, remainingSize);
  1383. if (ZSTD_isError(headerSize))
  1384. return headerSize;
  1385. /* Frame Header */
  1386. {
  1387. size_t const ret = ZSTD_getFrameParams(&fParams, ip, remainingSize);
  1388. if (ZSTD_isError(ret))
  1389. return ret;
  1390. if (ret > 0)
  1391. return ERROR(srcSize_wrong);
  1392. }
  1393. ip += headerSize;
  1394. remainingSize -= headerSize;
  1395. /* Loop on each block */
  1396. while (1) {
  1397. blockProperties_t blockProperties;
  1398. size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
  1399. if (ZSTD_isError(cBlockSize))
  1400. return cBlockSize;
  1401. if (ZSTD_blockHeaderSize + cBlockSize > remainingSize)
  1402. return ERROR(srcSize_wrong);
  1403. ip += ZSTD_blockHeaderSize + cBlockSize;
  1404. remainingSize -= ZSTD_blockHeaderSize + cBlockSize;
  1405. if (blockProperties.lastBlock)
  1406. break;
  1407. }
  1408. if (fParams.checksumFlag) { /* Frame content checksum */
  1409. if (remainingSize < 4)
  1410. return ERROR(srcSize_wrong);
  1411. ip += 4;
  1412. remainingSize -= 4;
  1413. }
  1414. return ip - ipstart;
  1415. }
  1416. }
  1417. /*! ZSTD_decompressFrame() :
  1418. * @dctx must be properly initialized */
  1419. static size_t ZSTD_decompressFrame(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void **srcPtr, size_t *srcSizePtr)
  1420. {
  1421. const BYTE *ip = (const BYTE *)(*srcPtr);
  1422. BYTE *const ostart = (BYTE * const)dst;
  1423. BYTE *const oend = ostart + dstCapacity;
  1424. BYTE *op = ostart;
  1425. size_t remainingSize = *srcSizePtr;
  1426. /* check */
  1427. if (remainingSize < ZSTD_frameHeaderSize_min + ZSTD_blockHeaderSize)
  1428. return ERROR(srcSize_wrong);
  1429. /* Frame Header */
  1430. {
  1431. size_t const frameHeaderSize = ZSTD_frameHeaderSize(ip, ZSTD_frameHeaderSize_prefix);
  1432. if (ZSTD_isError(frameHeaderSize))
  1433. return frameHeaderSize;
  1434. if (remainingSize < frameHeaderSize + ZSTD_blockHeaderSize)
  1435. return ERROR(srcSize_wrong);
  1436. CHECK_F(ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize));
  1437. ip += frameHeaderSize;
  1438. remainingSize -= frameHeaderSize;
  1439. }
  1440. /* Loop on each block */
  1441. while (1) {
  1442. size_t decodedSize;
  1443. blockProperties_t blockProperties;
  1444. size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
  1445. if (ZSTD_isError(cBlockSize))
  1446. return cBlockSize;
  1447. ip += ZSTD_blockHeaderSize;
  1448. remainingSize -= ZSTD_blockHeaderSize;
  1449. if (cBlockSize > remainingSize)
  1450. return ERROR(srcSize_wrong);
  1451. switch (blockProperties.blockType) {
  1452. case bt_compressed: decodedSize = ZSTD_decompressBlock_internal(dctx, op, oend - op, ip, cBlockSize); break;
  1453. case bt_raw: decodedSize = ZSTD_copyRawBlock(op, oend - op, ip, cBlockSize); break;
  1454. case bt_rle: decodedSize = ZSTD_generateNxBytes(op, oend - op, *ip, blockProperties.origSize); break;
  1455. case bt_reserved:
  1456. default: return ERROR(corruption_detected);
  1457. }
  1458. if (ZSTD_isError(decodedSize))
  1459. return decodedSize;
  1460. if (dctx->fParams.checksumFlag)
  1461. xxh64_update(&dctx->xxhState, op, decodedSize);
  1462. op += decodedSize;
  1463. ip += cBlockSize;
  1464. remainingSize -= cBlockSize;
  1465. if (blockProperties.lastBlock)
  1466. break;
  1467. }
  1468. if (dctx->fParams.checksumFlag) { /* Frame content checksum verification */
  1469. U32 const checkCalc = (U32)xxh64_digest(&dctx->xxhState);
  1470. U32 checkRead;
  1471. if (remainingSize < 4)
  1472. return ERROR(checksum_wrong);
  1473. checkRead = ZSTD_readLE32(ip);
  1474. if (checkRead != checkCalc)
  1475. return ERROR(checksum_wrong);
  1476. ip += 4;
  1477. remainingSize -= 4;
  1478. }
  1479. /* Allow caller to get size read */
  1480. *srcPtr = ip;
  1481. *srcSizePtr = remainingSize;
  1482. return op - ostart;
  1483. }
  1484. static const void *ZSTD_DDictDictContent(const ZSTD_DDict *ddict);
  1485. static size_t ZSTD_DDictDictSize(const ZSTD_DDict *ddict);
  1486. static size_t ZSTD_decompressMultiFrame(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize,
  1487. const ZSTD_DDict *ddict)
  1488. {
  1489. void *const dststart = dst;
  1490. if (ddict) {
  1491. if (dict) {
  1492. /* programmer error, these two cases should be mutually exclusive */
  1493. return ERROR(GENERIC);
  1494. }
  1495. dict = ZSTD_DDictDictContent(ddict);
  1496. dictSize = ZSTD_DDictDictSize(ddict);
  1497. }
  1498. while (srcSize >= ZSTD_frameHeaderSize_prefix) {
  1499. U32 magicNumber;
  1500. magicNumber = ZSTD_readLE32(src);
  1501. if (magicNumber != ZSTD_MAGICNUMBER) {
  1502. if ((magicNumber & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
  1503. size_t skippableSize;
  1504. if (srcSize < ZSTD_skippableHeaderSize)
  1505. return ERROR(srcSize_wrong);
  1506. skippableSize = ZSTD_readLE32((const BYTE *)src + 4) + ZSTD_skippableHeaderSize;
  1507. if (srcSize < skippableSize) {
  1508. return ERROR(srcSize_wrong);
  1509. }
  1510. src = (const BYTE *)src + skippableSize;
  1511. srcSize -= skippableSize;
  1512. continue;
  1513. } else {
  1514. return ERROR(prefix_unknown);
  1515. }
  1516. }
  1517. if (ddict) {
  1518. /* we were called from ZSTD_decompress_usingDDict */
  1519. ZSTD_refDDict(dctx, ddict);
  1520. } else {
  1521. /* this will initialize correctly with no dict if dict == NULL, so
  1522. * use this in all cases but ddict */
  1523. CHECK_F(ZSTD_decompressBegin_usingDict(dctx, dict, dictSize));
  1524. }
  1525. ZSTD_checkContinuity(dctx, dst);
  1526. {
  1527. const size_t res = ZSTD_decompressFrame(dctx, dst, dstCapacity, &src, &srcSize);
  1528. if (ZSTD_isError(res))
  1529. return res;
  1530. /* don't need to bounds check this, ZSTD_decompressFrame will have
  1531. * already */
  1532. dst = (BYTE *)dst + res;
  1533. dstCapacity -= res;
  1534. }
  1535. }
  1536. if (srcSize)
  1537. return ERROR(srcSize_wrong); /* input not entirely consumed */
  1538. return (BYTE *)dst - (BYTE *)dststart;
  1539. }
  1540. size_t ZSTD_decompress_usingDict(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const void *dict, size_t dictSize)
  1541. {
  1542. return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, dict, dictSize, NULL);
  1543. }
  1544. size_t ZSTD_decompressDCtx(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
  1545. {
  1546. return ZSTD_decompress_usingDict(dctx, dst, dstCapacity, src, srcSize, NULL, 0);
  1547. }
  1548. /*-**************************************
  1549. * Advanced Streaming Decompression API
  1550. * Bufferless and synchronous
  1551. ****************************************/
  1552. size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx *dctx) { return dctx->expected; }
  1553. ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx *dctx)
  1554. {
  1555. switch (dctx->stage) {
  1556. default: /* should not happen */
  1557. case ZSTDds_getFrameHeaderSize:
  1558. case ZSTDds_decodeFrameHeader: return ZSTDnit_frameHeader;
  1559. case ZSTDds_decodeBlockHeader: return ZSTDnit_blockHeader;
  1560. case ZSTDds_decompressBlock: return ZSTDnit_block;
  1561. case ZSTDds_decompressLastBlock: return ZSTDnit_lastBlock;
  1562. case ZSTDds_checkChecksum: return ZSTDnit_checksum;
  1563. case ZSTDds_decodeSkippableHeader:
  1564. case ZSTDds_skipFrame: return ZSTDnit_skippableFrame;
  1565. }
  1566. }
  1567. int ZSTD_isSkipFrame(ZSTD_DCtx *dctx) { return dctx->stage == ZSTDds_skipFrame; } /* for zbuff */
  1568. /** ZSTD_decompressContinue() :
  1569. * @return : nb of bytes generated into `dst` (necessarily <= `dstCapacity)
  1570. * or an error code, which can be tested using ZSTD_isError() */
  1571. size_t ZSTD_decompressContinue(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize)
  1572. {
  1573. /* Sanity check */
  1574. if (srcSize != dctx->expected)
  1575. return ERROR(srcSize_wrong);
  1576. if (dstCapacity)
  1577. ZSTD_checkContinuity(dctx, dst);
  1578. switch (dctx->stage) {
  1579. case ZSTDds_getFrameHeaderSize:
  1580. if (srcSize != ZSTD_frameHeaderSize_prefix)
  1581. return ERROR(srcSize_wrong); /* impossible */
  1582. if ((ZSTD_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */
  1583. memcpy(dctx->headerBuffer, src, ZSTD_frameHeaderSize_prefix);
  1584. dctx->expected = ZSTD_skippableHeaderSize - ZSTD_frameHeaderSize_prefix; /* magic number + skippable frame length */
  1585. dctx->stage = ZSTDds_decodeSkippableHeader;
  1586. return 0;
  1587. }
  1588. dctx->headerSize = ZSTD_frameHeaderSize(src, ZSTD_frameHeaderSize_prefix);
  1589. if (ZSTD_isError(dctx->headerSize))
  1590. return dctx->headerSize;
  1591. memcpy(dctx->headerBuffer, src, ZSTD_frameHeaderSize_prefix);
  1592. if (dctx->headerSize > ZSTD_frameHeaderSize_prefix) {
  1593. dctx->expected = dctx->headerSize - ZSTD_frameHeaderSize_prefix;
  1594. dctx->stage = ZSTDds_decodeFrameHeader;
  1595. return 0;
  1596. }
  1597. dctx->expected = 0; /* not necessary to copy more */
  1598. case ZSTDds_decodeFrameHeader:
  1599. memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, dctx->expected);
  1600. CHECK_F(ZSTD_decodeFrameHeader(dctx, dctx->headerBuffer, dctx->headerSize));
  1601. dctx->expected = ZSTD_blockHeaderSize;
  1602. dctx->stage = ZSTDds_decodeBlockHeader;
  1603. return 0;
  1604. case ZSTDds_decodeBlockHeader: {
  1605. blockProperties_t bp;
  1606. size_t const cBlockSize = ZSTD_getcBlockSize(src, ZSTD_blockHeaderSize, &bp);
  1607. if (ZSTD_isError(cBlockSize))
  1608. return cBlockSize;
  1609. dctx->expected = cBlockSize;
  1610. dctx->bType = bp.blockType;
  1611. dctx->rleSize = bp.origSize;
  1612. if (cBlockSize) {
  1613. dctx->stage = bp.lastBlock ? ZSTDds_decompressLastBlock : ZSTDds_decompressBlock;
  1614. return 0;
  1615. }
  1616. /* empty block */
  1617. if (bp.lastBlock) {
  1618. if (dctx->fParams.checksumFlag) {
  1619. dctx->expected = 4;
  1620. dctx->stage = ZSTDds_checkChecksum;
  1621. } else {
  1622. dctx->expected = 0; /* end of frame */
  1623. dctx->stage = ZSTDds_getFrameHeaderSize;
  1624. }
  1625. } else {
  1626. dctx->expected = 3; /* go directly to next header */
  1627. dctx->stage = ZSTDds_decodeBlockHeader;
  1628. }
  1629. return 0;
  1630. }
  1631. case ZSTDds_decompressLastBlock:
  1632. case ZSTDds_decompressBlock: {
  1633. size_t rSize;
  1634. switch (dctx->bType) {
  1635. case bt_compressed: rSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize); break;
  1636. case bt_raw: rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, srcSize); break;
  1637. case bt_rle: rSize = ZSTD_setRleBlock(dst, dstCapacity, src, srcSize, dctx->rleSize); break;
  1638. case bt_reserved: /* should never happen */
  1639. default: return ERROR(corruption_detected);
  1640. }
  1641. if (ZSTD_isError(rSize))
  1642. return rSize;
  1643. if (dctx->fParams.checksumFlag)
  1644. xxh64_update(&dctx->xxhState, dst, rSize);
  1645. if (dctx->stage == ZSTDds_decompressLastBlock) { /* end of frame */
  1646. if (dctx->fParams.checksumFlag) { /* another round for frame checksum */
  1647. dctx->expected = 4;
  1648. dctx->stage = ZSTDds_checkChecksum;
  1649. } else {
  1650. dctx->expected = 0; /* ends here */
  1651. dctx->stage = ZSTDds_getFrameHeaderSize;
  1652. }
  1653. } else {
  1654. dctx->stage = ZSTDds_decodeBlockHeader;
  1655. dctx->expected = ZSTD_blockHeaderSize;
  1656. dctx->previousDstEnd = (char *)dst + rSize;
  1657. }
  1658. return rSize;
  1659. }
  1660. case ZSTDds_checkChecksum: {
  1661. U32 const h32 = (U32)xxh64_digest(&dctx->xxhState);
  1662. U32 const check32 = ZSTD_readLE32(src); /* srcSize == 4, guaranteed by dctx->expected */
  1663. if (check32 != h32)
  1664. return ERROR(checksum_wrong);
  1665. dctx->expected = 0;
  1666. dctx->stage = ZSTDds_getFrameHeaderSize;
  1667. return 0;
  1668. }
  1669. case ZSTDds_decodeSkippableHeader: {
  1670. memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, dctx->expected);
  1671. dctx->expected = ZSTD_readLE32(dctx->headerBuffer + 4);
  1672. dctx->stage = ZSTDds_skipFrame;
  1673. return 0;
  1674. }
  1675. case ZSTDds_skipFrame: {
  1676. dctx->expected = 0;
  1677. dctx->stage = ZSTDds_getFrameHeaderSize;
  1678. return 0;
  1679. }
  1680. default:
  1681. return ERROR(GENERIC); /* impossible */
  1682. }
  1683. }
  1684. static size_t ZSTD_refDictContent(ZSTD_DCtx *dctx, const void *dict, size_t dictSize)
  1685. {
  1686. dctx->dictEnd = dctx->previousDstEnd;
  1687. dctx->vBase = (const char *)dict - ((const char *)(dctx->previousDstEnd) - (const char *)(dctx->base));
  1688. dctx->base = dict;
  1689. dctx->previousDstEnd = (const char *)dict + dictSize;
  1690. return 0;
  1691. }
  1692. /* ZSTD_loadEntropy() :
  1693. * dict : must point at beginning of a valid zstd dictionary
  1694. * @return : size of entropy tables read */
  1695. static size_t ZSTD_loadEntropy(ZSTD_entropyTables_t *entropy, const void *const dict, size_t const dictSize)
  1696. {
  1697. const BYTE *dictPtr = (const BYTE *)dict;
  1698. const BYTE *const dictEnd = dictPtr + dictSize;
  1699. if (dictSize <= 8)
  1700. return ERROR(dictionary_corrupted);
  1701. dictPtr += 8; /* skip header = magic + dictID */
  1702. {
  1703. size_t const hSize = HUF_readDTableX4_wksp(entropy->hufTable, dictPtr, dictEnd - dictPtr, entropy->workspace, sizeof(entropy->workspace));
  1704. if (HUF_isError(hSize))
  1705. return ERROR(dictionary_corrupted);
  1706. dictPtr += hSize;
  1707. }
  1708. {
  1709. short offcodeNCount[MaxOff + 1];
  1710. U32 offcodeMaxValue = MaxOff, offcodeLog;
  1711. size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd - dictPtr);
  1712. if (FSE_isError(offcodeHeaderSize))
  1713. return ERROR(dictionary_corrupted);
  1714. if (offcodeLog > OffFSELog)
  1715. return ERROR(dictionary_corrupted);
  1716. CHECK_E(FSE_buildDTable_wksp(entropy->OFTable, offcodeNCount, offcodeMaxValue, offcodeLog, entropy->workspace, sizeof(entropy->workspace)), dictionary_corrupted);
  1717. dictPtr += offcodeHeaderSize;
  1718. }
  1719. {
  1720. short matchlengthNCount[MaxML + 1];
  1721. unsigned matchlengthMaxValue = MaxML, matchlengthLog;
  1722. size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd - dictPtr);
  1723. if (FSE_isError(matchlengthHeaderSize))
  1724. return ERROR(dictionary_corrupted);
  1725. if (matchlengthLog > MLFSELog)
  1726. return ERROR(dictionary_corrupted);
  1727. CHECK_E(FSE_buildDTable_wksp(entropy->MLTable, matchlengthNCount, matchlengthMaxValue, matchlengthLog, entropy->workspace, sizeof(entropy->workspace)), dictionary_corrupted);
  1728. dictPtr += matchlengthHeaderSize;
  1729. }
  1730. {
  1731. short litlengthNCount[MaxLL + 1];
  1732. unsigned litlengthMaxValue = MaxLL, litlengthLog;
  1733. size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd - dictPtr);
  1734. if (FSE_isError(litlengthHeaderSize))
  1735. return ERROR(dictionary_corrupted);
  1736. if (litlengthLog > LLFSELog)
  1737. return ERROR(dictionary_corrupted);
  1738. CHECK_E(FSE_buildDTable_wksp(entropy->LLTable, litlengthNCount, litlengthMaxValue, litlengthLog, entropy->workspace, sizeof(entropy->workspace)), dictionary_corrupted);
  1739. dictPtr += litlengthHeaderSize;
  1740. }
  1741. if (dictPtr + 12 > dictEnd)
  1742. return ERROR(dictionary_corrupted);
  1743. {
  1744. int i;
  1745. size_t const dictContentSize = (size_t)(dictEnd - (dictPtr + 12));
  1746. for (i = 0; i < 3; i++) {
  1747. U32 const rep = ZSTD_readLE32(dictPtr);
  1748. dictPtr += 4;
  1749. if (rep == 0 || rep >= dictContentSize)
  1750. return ERROR(dictionary_corrupted);
  1751. entropy->rep[i] = rep;
  1752. }
  1753. }
  1754. return dictPtr - (const BYTE *)dict;
  1755. }
  1756. static size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx *dctx, const void *dict, size_t dictSize)
  1757. {
  1758. if (dictSize < 8)
  1759. return ZSTD_refDictContent(dctx, dict, dictSize);
  1760. {
  1761. U32 const magic = ZSTD_readLE32(dict);
  1762. if (magic != ZSTD_DICT_MAGIC) {
  1763. return ZSTD_refDictContent(dctx, dict, dictSize); /* pure content mode */
  1764. }
  1765. }
  1766. dctx->dictID = ZSTD_readLE32((const char *)dict + 4);
  1767. /* load entropy tables */
  1768. {
  1769. size_t const eSize = ZSTD_loadEntropy(&dctx->entropy, dict, dictSize);
  1770. if (ZSTD_isError(eSize))
  1771. return ERROR(dictionary_corrupted);
  1772. dict = (const char *)dict + eSize;
  1773. dictSize -= eSize;
  1774. }
  1775. dctx->litEntropy = dctx->fseEntropy = 1;
  1776. /* reference dictionary content */
  1777. return ZSTD_refDictContent(dctx, dict, dictSize);
  1778. }
  1779. size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx *dctx, const void *dict, size_t dictSize)
  1780. {
  1781. CHECK_F(ZSTD_decompressBegin(dctx));
  1782. if (dict && dictSize)
  1783. CHECK_E(ZSTD_decompress_insertDictionary(dctx, dict, dictSize), dictionary_corrupted);
  1784. return 0;
  1785. }
  1786. /* ====== ZSTD_DDict ====== */
  1787. struct ZSTD_DDict_s {
  1788. void *dictBuffer;
  1789. const void *dictContent;
  1790. size_t dictSize;
  1791. ZSTD_entropyTables_t entropy;
  1792. U32 dictID;
  1793. U32 entropyPresent;
  1794. ZSTD_customMem cMem;
  1795. }; /* typedef'd to ZSTD_DDict within "zstd.h" */
  1796. size_t ZSTD_DDictWorkspaceBound(void) { return ZSTD_ALIGN(sizeof(ZSTD_stack)) + ZSTD_ALIGN(sizeof(ZSTD_DDict)); }
  1797. static const void *ZSTD_DDictDictContent(const ZSTD_DDict *ddict) { return ddict->dictContent; }
  1798. static size_t ZSTD_DDictDictSize(const ZSTD_DDict *ddict) { return ddict->dictSize; }
  1799. static void ZSTD_refDDict(ZSTD_DCtx *dstDCtx, const ZSTD_DDict *ddict)
  1800. {
  1801. ZSTD_decompressBegin(dstDCtx); /* init */
  1802. if (ddict) { /* support refDDict on NULL */
  1803. dstDCtx->dictID = ddict->dictID;
  1804. dstDCtx->base = ddict->dictContent;
  1805. dstDCtx->vBase = ddict->dictContent;
  1806. dstDCtx->dictEnd = (const BYTE *)ddict->dictContent + ddict->dictSize;
  1807. dstDCtx->previousDstEnd = dstDCtx->dictEnd;
  1808. if (ddict->entropyPresent) {
  1809. dstDCtx->litEntropy = 1;
  1810. dstDCtx->fseEntropy = 1;
  1811. dstDCtx->LLTptr = ddict->entropy.LLTable;
  1812. dstDCtx->MLTptr = ddict->entropy.MLTable;
  1813. dstDCtx->OFTptr = ddict->entropy.OFTable;
  1814. dstDCtx->HUFptr = ddict->entropy.hufTable;
  1815. dstDCtx->entropy.rep[0] = ddict->entropy.rep[0];
  1816. dstDCtx->entropy.rep[1] = ddict->entropy.rep[1];
  1817. dstDCtx->entropy.rep[2] = ddict->entropy.rep[2];
  1818. } else {
  1819. dstDCtx->litEntropy = 0;
  1820. dstDCtx->fseEntropy = 0;
  1821. }
  1822. }
  1823. }
  1824. static size_t ZSTD_loadEntropy_inDDict(ZSTD_DDict *ddict)
  1825. {
  1826. ddict->dictID = 0;
  1827. ddict->entropyPresent = 0;
  1828. if (ddict->dictSize < 8)
  1829. return 0;
  1830. {
  1831. U32 const magic = ZSTD_readLE32(ddict->dictContent);
  1832. if (magic != ZSTD_DICT_MAGIC)
  1833. return 0; /* pure content mode */
  1834. }
  1835. ddict->dictID = ZSTD_readLE32((const char *)ddict->dictContent + 4);
  1836. /* load entropy tables */
  1837. CHECK_E(ZSTD_loadEntropy(&ddict->entropy, ddict->dictContent, ddict->dictSize), dictionary_corrupted);
  1838. ddict->entropyPresent = 1;
  1839. return 0;
  1840. }
  1841. static ZSTD_DDict *ZSTD_createDDict_advanced(const void *dict, size_t dictSize, unsigned byReference, ZSTD_customMem customMem)
  1842. {
  1843. if (!customMem.customAlloc || !customMem.customFree)
  1844. return NULL;
  1845. {
  1846. ZSTD_DDict *const ddict = (ZSTD_DDict *)ZSTD_malloc(sizeof(ZSTD_DDict), customMem);
  1847. if (!ddict)
  1848. return NULL;
  1849. ddict->cMem = customMem;
  1850. if ((byReference) || (!dict) || (!dictSize)) {
  1851. ddict->dictBuffer = NULL;
  1852. ddict->dictContent = dict;
  1853. } else {
  1854. void *const internalBuffer = ZSTD_malloc(dictSize, customMem);
  1855. if (!internalBuffer) {
  1856. ZSTD_freeDDict(ddict);
  1857. return NULL;
  1858. }
  1859. memcpy(internalBuffer, dict, dictSize);
  1860. ddict->dictBuffer = internalBuffer;
  1861. ddict->dictContent = internalBuffer;
  1862. }
  1863. ddict->dictSize = dictSize;
  1864. ddict->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); /* cover both little and big endian */
  1865. /* parse dictionary content */
  1866. {
  1867. size_t const errorCode = ZSTD_loadEntropy_inDDict(ddict);
  1868. if (ZSTD_isError(errorCode)) {
  1869. ZSTD_freeDDict(ddict);
  1870. return NULL;
  1871. }
  1872. }
  1873. return ddict;
  1874. }
  1875. }
  1876. /*! ZSTD_initDDict() :
  1877. * Create a digested dictionary, to start decompression without startup delay.
  1878. * `dict` content is copied inside DDict.
  1879. * Consequently, `dict` can be released after `ZSTD_DDict` creation */
  1880. ZSTD_DDict *ZSTD_initDDict(const void *dict, size_t dictSize, void *workspace, size_t workspaceSize)
  1881. {
  1882. ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
  1883. return ZSTD_createDDict_advanced(dict, dictSize, 1, stackMem);
  1884. }
  1885. size_t ZSTD_freeDDict(ZSTD_DDict *ddict)
  1886. {
  1887. if (ddict == NULL)
  1888. return 0; /* support free on NULL */
  1889. {
  1890. ZSTD_customMem const cMem = ddict->cMem;
  1891. ZSTD_free(ddict->dictBuffer, cMem);
  1892. ZSTD_free(ddict, cMem);
  1893. return 0;
  1894. }
  1895. }
  1896. /*! ZSTD_getDictID_fromDict() :
  1897. * Provides the dictID stored within dictionary.
  1898. * if @return == 0, the dictionary is not conformant with Zstandard specification.
  1899. * It can still be loaded, but as a content-only dictionary. */
  1900. unsigned ZSTD_getDictID_fromDict(const void *dict, size_t dictSize)
  1901. {
  1902. if (dictSize < 8)
  1903. return 0;
  1904. if (ZSTD_readLE32(dict) != ZSTD_DICT_MAGIC)
  1905. return 0;
  1906. return ZSTD_readLE32((const char *)dict + 4);
  1907. }
  1908. /*! ZSTD_getDictID_fromDDict() :
  1909. * Provides the dictID of the dictionary loaded into `ddict`.
  1910. * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
  1911. * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
  1912. unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict *ddict)
  1913. {
  1914. if (ddict == NULL)
  1915. return 0;
  1916. return ZSTD_getDictID_fromDict(ddict->dictContent, ddict->dictSize);
  1917. }
  1918. /*! ZSTD_getDictID_fromFrame() :
  1919. * Provides the dictID required to decompressed the frame stored within `src`.
  1920. * If @return == 0, the dictID could not be decoded.
  1921. * This could for one of the following reasons :
  1922. * - The frame does not require a dictionary to be decoded (most common case).
  1923. * - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden information.
  1924. * Note : this use case also happens when using a non-conformant dictionary.
  1925. * - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`).
  1926. * - This is not a Zstandard frame.
  1927. * When identifying the exact failure cause, it's possible to used ZSTD_getFrameParams(), which will provide a more precise error code. */
  1928. unsigned ZSTD_getDictID_fromFrame(const void *src, size_t srcSize)
  1929. {
  1930. ZSTD_frameParams zfp = {0, 0, 0, 0};
  1931. size_t const hError = ZSTD_getFrameParams(&zfp, src, srcSize);
  1932. if (ZSTD_isError(hError))
  1933. return 0;
  1934. return zfp.dictID;
  1935. }
  1936. /*! ZSTD_decompress_usingDDict() :
  1937. * Decompression using a pre-digested Dictionary
  1938. * Use dictionary without significant overhead. */
  1939. size_t ZSTD_decompress_usingDDict(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, const void *src, size_t srcSize, const ZSTD_DDict *ddict)
  1940. {
  1941. /* pass content and size in case legacy frames are encountered */
  1942. return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, NULL, 0, ddict);
  1943. }
  1944. /*=====================================
  1945. * Streaming decompression
  1946. *====================================*/
  1947. typedef enum { zdss_init, zdss_loadHeader, zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
  1948. /* *** Resource management *** */
  1949. struct ZSTD_DStream_s {
  1950. ZSTD_DCtx *dctx;
  1951. ZSTD_DDict *ddictLocal;
  1952. const ZSTD_DDict *ddict;
  1953. ZSTD_frameParams fParams;
  1954. ZSTD_dStreamStage stage;
  1955. char *inBuff;
  1956. size_t inBuffSize;
  1957. size_t inPos;
  1958. size_t maxWindowSize;
  1959. char *outBuff;
  1960. size_t outBuffSize;
  1961. size_t outStart;
  1962. size_t outEnd;
  1963. size_t blockSize;
  1964. BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX]; /* tmp buffer to store frame header */
  1965. size_t lhSize;
  1966. ZSTD_customMem customMem;
  1967. void *legacyContext;
  1968. U32 previousLegacyVersion;
  1969. U32 legacyVersion;
  1970. U32 hostageByte;
  1971. }; /* typedef'd to ZSTD_DStream within "zstd.h" */
  1972. size_t ZSTD_DStreamWorkspaceBound(size_t maxWindowSize)
  1973. {
  1974. size_t const blockSize = MIN(maxWindowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
  1975. size_t const inBuffSize = blockSize;
  1976. size_t const outBuffSize = maxWindowSize + blockSize + WILDCOPY_OVERLENGTH * 2;
  1977. return ZSTD_DCtxWorkspaceBound() + ZSTD_ALIGN(sizeof(ZSTD_DStream)) + ZSTD_ALIGN(inBuffSize) + ZSTD_ALIGN(outBuffSize);
  1978. }
  1979. static ZSTD_DStream *ZSTD_createDStream_advanced(ZSTD_customMem customMem)
  1980. {
  1981. ZSTD_DStream *zds;
  1982. if (!customMem.customAlloc || !customMem.customFree)
  1983. return NULL;
  1984. zds = (ZSTD_DStream *)ZSTD_malloc(sizeof(ZSTD_DStream), customMem);
  1985. if (zds == NULL)
  1986. return NULL;
  1987. memset(zds, 0, sizeof(ZSTD_DStream));
  1988. memcpy(&zds->customMem, &customMem, sizeof(ZSTD_customMem));
  1989. zds->dctx = ZSTD_createDCtx_advanced(customMem);
  1990. if (zds->dctx == NULL) {
  1991. ZSTD_freeDStream(zds);
  1992. return NULL;
  1993. }
  1994. zds->stage = zdss_init;
  1995. zds->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT;
  1996. return zds;
  1997. }
  1998. ZSTD_DStream *ZSTD_initDStream(size_t maxWindowSize, void *workspace, size_t workspaceSize)
  1999. {
  2000. ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
  2001. ZSTD_DStream *zds = ZSTD_createDStream_advanced(stackMem);
  2002. if (!zds) {
  2003. return NULL;
  2004. }
  2005. zds->maxWindowSize = maxWindowSize;
  2006. zds->stage = zdss_loadHeader;
  2007. zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
  2008. ZSTD_freeDDict(zds->ddictLocal);
  2009. zds->ddictLocal = NULL;
  2010. zds->ddict = zds->ddictLocal;
  2011. zds->legacyVersion = 0;
  2012. zds->hostageByte = 0;
  2013. {
  2014. size_t const blockSize = MIN(zds->maxWindowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
  2015. size_t const neededOutSize = zds->maxWindowSize + blockSize + WILDCOPY_OVERLENGTH * 2;
  2016. zds->inBuff = (char *)ZSTD_malloc(blockSize, zds->customMem);
  2017. zds->inBuffSize = blockSize;
  2018. zds->outBuff = (char *)ZSTD_malloc(neededOutSize, zds->customMem);
  2019. zds->outBuffSize = neededOutSize;
  2020. if (zds->inBuff == NULL || zds->outBuff == NULL) {
  2021. ZSTD_freeDStream(zds);
  2022. return NULL;
  2023. }
  2024. }
  2025. return zds;
  2026. }
  2027. ZSTD_DStream *ZSTD_initDStream_usingDDict(size_t maxWindowSize, const ZSTD_DDict *ddict, void *workspace, size_t workspaceSize)
  2028. {
  2029. ZSTD_DStream *zds = ZSTD_initDStream(maxWindowSize, workspace, workspaceSize);
  2030. if (zds) {
  2031. zds->ddict = ddict;
  2032. }
  2033. return zds;
  2034. }
  2035. size_t ZSTD_freeDStream(ZSTD_DStream *zds)
  2036. {
  2037. if (zds == NULL)
  2038. return 0; /* support free on null */
  2039. {
  2040. ZSTD_customMem const cMem = zds->customMem;
  2041. ZSTD_freeDCtx(zds->dctx);
  2042. zds->dctx = NULL;
  2043. ZSTD_freeDDict(zds->ddictLocal);
  2044. zds->ddictLocal = NULL;
  2045. ZSTD_free(zds->inBuff, cMem);
  2046. zds->inBuff = NULL;
  2047. ZSTD_free(zds->outBuff, cMem);
  2048. zds->outBuff = NULL;
  2049. ZSTD_free(zds, cMem);
  2050. return 0;
  2051. }
  2052. }
  2053. /* *** Initialization *** */
  2054. size_t ZSTD_DStreamInSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX + ZSTD_blockHeaderSize; }
  2055. size_t ZSTD_DStreamOutSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX; }
  2056. size_t ZSTD_resetDStream(ZSTD_DStream *zds)
  2057. {
  2058. zds->stage = zdss_loadHeader;
  2059. zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
  2060. zds->legacyVersion = 0;
  2061. zds->hostageByte = 0;
  2062. return ZSTD_frameHeaderSize_prefix;
  2063. }
  2064. /* ***** Decompression ***** */
  2065. ZSTD_STATIC size_t ZSTD_limitCopy(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
  2066. {
  2067. size_t const length = MIN(dstCapacity, srcSize);
  2068. memcpy(dst, src, length);
  2069. return length;
  2070. }
  2071. size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inBuffer *input)
  2072. {
  2073. const char *const istart = (const char *)(input->src) + input->pos;
  2074. const char *const iend = (const char *)(input->src) + input->size;
  2075. const char *ip = istart;
  2076. char *const ostart = (char *)(output->dst) + output->pos;
  2077. char *const oend = (char *)(output->dst) + output->size;
  2078. char *op = ostart;
  2079. U32 someMoreWork = 1;
  2080. while (someMoreWork) {
  2081. switch (zds->stage) {
  2082. case zdss_init:
  2083. ZSTD_resetDStream(zds); /* transparent reset on starting decoding a new frame */
  2084. /* fall-through */
  2085. case zdss_loadHeader: {
  2086. size_t const hSize = ZSTD_getFrameParams(&zds->fParams, zds->headerBuffer, zds->lhSize);
  2087. if (ZSTD_isError(hSize))
  2088. return hSize;
  2089. if (hSize != 0) { /* need more input */
  2090. size_t const toLoad = hSize - zds->lhSize; /* if hSize!=0, hSize > zds->lhSize */
  2091. if (toLoad > (size_t)(iend - ip)) { /* not enough input to load full header */
  2092. memcpy(zds->headerBuffer + zds->lhSize, ip, iend - ip);
  2093. zds->lhSize += iend - ip;
  2094. input->pos = input->size;
  2095. return (MAX(ZSTD_frameHeaderSize_min, hSize) - zds->lhSize) +
  2096. ZSTD_blockHeaderSize; /* remaining header bytes + next block header */
  2097. }
  2098. memcpy(zds->headerBuffer + zds->lhSize, ip, toLoad);
  2099. zds->lhSize = hSize;
  2100. ip += toLoad;
  2101. break;
  2102. }
  2103. /* check for single-pass mode opportunity */
  2104. if (zds->fParams.frameContentSize && zds->fParams.windowSize /* skippable frame if == 0 */
  2105. && (U64)(size_t)(oend - op) >= zds->fParams.frameContentSize) {
  2106. size_t const cSize = ZSTD_findFrameCompressedSize(istart, iend - istart);
  2107. if (cSize <= (size_t)(iend - istart)) {
  2108. size_t const decompressedSize = ZSTD_decompress_usingDDict(zds->dctx, op, oend - op, istart, cSize, zds->ddict);
  2109. if (ZSTD_isError(decompressedSize))
  2110. return decompressedSize;
  2111. ip = istart + cSize;
  2112. op += decompressedSize;
  2113. zds->dctx->expected = 0;
  2114. zds->stage = zdss_init;
  2115. someMoreWork = 0;
  2116. break;
  2117. }
  2118. }
  2119. /* Consume header */
  2120. ZSTD_refDDict(zds->dctx, zds->ddict);
  2121. {
  2122. size_t const h1Size = ZSTD_nextSrcSizeToDecompress(zds->dctx); /* == ZSTD_frameHeaderSize_prefix */
  2123. CHECK_F(ZSTD_decompressContinue(zds->dctx, NULL, 0, zds->headerBuffer, h1Size));
  2124. {
  2125. size_t const h2Size = ZSTD_nextSrcSizeToDecompress(zds->dctx);
  2126. CHECK_F(ZSTD_decompressContinue(zds->dctx, NULL, 0, zds->headerBuffer + h1Size, h2Size));
  2127. }
  2128. }
  2129. zds->fParams.windowSize = MAX(zds->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN);
  2130. if (zds->fParams.windowSize > zds->maxWindowSize)
  2131. return ERROR(frameParameter_windowTooLarge);
  2132. /* Buffers are preallocated, but double check */
  2133. {
  2134. size_t const blockSize = MIN(zds->maxWindowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
  2135. size_t const neededOutSize = zds->maxWindowSize + blockSize + WILDCOPY_OVERLENGTH * 2;
  2136. if (zds->inBuffSize < blockSize) {
  2137. return ERROR(GENERIC);
  2138. }
  2139. if (zds->outBuffSize < neededOutSize) {
  2140. return ERROR(GENERIC);
  2141. }
  2142. zds->blockSize = blockSize;
  2143. }
  2144. zds->stage = zdss_read;
  2145. }
  2146. /* pass-through */
  2147. case zdss_read: {
  2148. size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
  2149. if (neededInSize == 0) { /* end of frame */
  2150. zds->stage = zdss_init;
  2151. someMoreWork = 0;
  2152. break;
  2153. }
  2154. if ((size_t)(iend - ip) >= neededInSize) { /* decode directly from src */
  2155. const int isSkipFrame = ZSTD_isSkipFrame(zds->dctx);
  2156. size_t const decodedSize = ZSTD_decompressContinue(zds->dctx, zds->outBuff + zds->outStart,
  2157. (isSkipFrame ? 0 : zds->outBuffSize - zds->outStart), ip, neededInSize);
  2158. if (ZSTD_isError(decodedSize))
  2159. return decodedSize;
  2160. ip += neededInSize;
  2161. if (!decodedSize && !isSkipFrame)
  2162. break; /* this was just a header */
  2163. zds->outEnd = zds->outStart + decodedSize;
  2164. zds->stage = zdss_flush;
  2165. break;
  2166. }
  2167. if (ip == iend) {
  2168. someMoreWork = 0;
  2169. break;
  2170. } /* no more input */
  2171. zds->stage = zdss_load;
  2172. /* pass-through */
  2173. }
  2174. case zdss_load: {
  2175. size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
  2176. size_t const toLoad = neededInSize - zds->inPos; /* should always be <= remaining space within inBuff */
  2177. size_t loadedSize;
  2178. if (toLoad > zds->inBuffSize - zds->inPos)
  2179. return ERROR(corruption_detected); /* should never happen */
  2180. loadedSize = ZSTD_limitCopy(zds->inBuff + zds->inPos, toLoad, ip, iend - ip);
  2181. ip += loadedSize;
  2182. zds->inPos += loadedSize;
  2183. if (loadedSize < toLoad) {
  2184. someMoreWork = 0;
  2185. break;
  2186. } /* not enough input, wait for more */
  2187. /* decode loaded input */
  2188. {
  2189. const int isSkipFrame = ZSTD_isSkipFrame(zds->dctx);
  2190. size_t const decodedSize = ZSTD_decompressContinue(zds->dctx, zds->outBuff + zds->outStart, zds->outBuffSize - zds->outStart,
  2191. zds->inBuff, neededInSize);
  2192. if (ZSTD_isError(decodedSize))
  2193. return decodedSize;
  2194. zds->inPos = 0; /* input is consumed */
  2195. if (!decodedSize && !isSkipFrame) {
  2196. zds->stage = zdss_read;
  2197. break;
  2198. } /* this was just a header */
  2199. zds->outEnd = zds->outStart + decodedSize;
  2200. zds->stage = zdss_flush;
  2201. /* pass-through */
  2202. }
  2203. }
  2204. case zdss_flush: {
  2205. size_t const toFlushSize = zds->outEnd - zds->outStart;
  2206. size_t const flushedSize = ZSTD_limitCopy(op, oend - op, zds->outBuff + zds->outStart, toFlushSize);
  2207. op += flushedSize;
  2208. zds->outStart += flushedSize;
  2209. if (flushedSize == toFlushSize) { /* flush completed */
  2210. zds->stage = zdss_read;
  2211. if (zds->outStart + zds->blockSize > zds->outBuffSize)
  2212. zds->outStart = zds->outEnd = 0;
  2213. break;
  2214. }
  2215. /* cannot complete flush */
  2216. someMoreWork = 0;
  2217. break;
  2218. }
  2219. default:
  2220. return ERROR(GENERIC); /* impossible */
  2221. }
  2222. }
  2223. /* result */
  2224. input->pos += (size_t)(ip - istart);
  2225. output->pos += (size_t)(op - ostart);
  2226. {
  2227. size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zds->dctx);
  2228. if (!nextSrcSizeHint) { /* frame fully decoded */
  2229. if (zds->outEnd == zds->outStart) { /* output fully flushed */
  2230. if (zds->hostageByte) {
  2231. if (input->pos >= input->size) {
  2232. zds->stage = zdss_read;
  2233. return 1;
  2234. } /* can't release hostage (not present) */
  2235. input->pos++; /* release hostage */
  2236. }
  2237. return 0;
  2238. }
  2239. if (!zds->hostageByte) { /* output not fully flushed; keep last byte as hostage; will be released when all output is flushed */
  2240. input->pos--; /* note : pos > 0, otherwise, impossible to finish reading last block */
  2241. zds->hostageByte = 1;
  2242. }
  2243. return 1;
  2244. }
  2245. nextSrcSizeHint += ZSTD_blockHeaderSize * (ZSTD_nextInputType(zds->dctx) == ZSTDnit_block); /* preload header of next block */
  2246. if (zds->inPos > nextSrcSizeHint)
  2247. return ERROR(GENERIC); /* should never happen */
  2248. nextSrcSizeHint -= zds->inPos; /* already loaded*/
  2249. return nextSrcSizeHint;
  2250. }
  2251. }
  2252. EXPORT_SYMBOL(ZSTD_DCtxWorkspaceBound);
  2253. EXPORT_SYMBOL(ZSTD_initDCtx);
  2254. EXPORT_SYMBOL(ZSTD_decompressDCtx);
  2255. EXPORT_SYMBOL(ZSTD_decompress_usingDict);
  2256. EXPORT_SYMBOL(ZSTD_DDictWorkspaceBound);
  2257. EXPORT_SYMBOL(ZSTD_initDDict);
  2258. EXPORT_SYMBOL(ZSTD_decompress_usingDDict);
  2259. EXPORT_SYMBOL(ZSTD_DStreamWorkspaceBound);
  2260. EXPORT_SYMBOL(ZSTD_initDStream);
  2261. EXPORT_SYMBOL(ZSTD_initDStream_usingDDict);
  2262. EXPORT_SYMBOL(ZSTD_resetDStream);
  2263. EXPORT_SYMBOL(ZSTD_decompressStream);
  2264. EXPORT_SYMBOL(ZSTD_DStreamInSize);
  2265. EXPORT_SYMBOL(ZSTD_DStreamOutSize);
  2266. EXPORT_SYMBOL(ZSTD_findFrameCompressedSize);
  2267. EXPORT_SYMBOL(ZSTD_getFrameContentSize);
  2268. EXPORT_SYMBOL(ZSTD_findDecompressedSize);
  2269. EXPORT_SYMBOL(ZSTD_isFrame);
  2270. EXPORT_SYMBOL(ZSTD_getDictID_fromDict);
  2271. EXPORT_SYMBOL(ZSTD_getDictID_fromDDict);
  2272. EXPORT_SYMBOL(ZSTD_getDictID_fromFrame);
  2273. EXPORT_SYMBOL(ZSTD_getFrameParams);
  2274. EXPORT_SYMBOL(ZSTD_decompressBegin);
  2275. EXPORT_SYMBOL(ZSTD_decompressBegin_usingDict);
  2276. EXPORT_SYMBOL(ZSTD_copyDCtx);
  2277. EXPORT_SYMBOL(ZSTD_nextSrcSizeToDecompress);
  2278. EXPORT_SYMBOL(ZSTD_decompressContinue);
  2279. EXPORT_SYMBOL(ZSTD_nextInputType);
  2280. EXPORT_SYMBOL(ZSTD_decompressBlock);
  2281. EXPORT_SYMBOL(ZSTD_insertBlock);