1// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
2/*
3 * Copyright (c) Meta Platforms, Inc. and affiliates.
4 * All rights reserved.
5 *
6 * This source code is licensed under both the BSD-style license (found in the
7 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
8 * in the COPYING file in the root directory of this source tree).
9 * You may select, at your option, one of the above-listed licenses.
10 */
11
12
13/* ***************************************************************
14* Tuning parameters
15*****************************************************************/
16/*!
17 * HEAPMODE :
18 * Select how default decompression function ZSTD_decompress() allocates its context,
19 * on stack (0), or into heap (1, default; requires malloc()).
20 * Note that functions with explicit context such as ZSTD_decompressDCtx() are unaffected.
21 */
22#ifndef ZSTD_HEAPMODE
23# define ZSTD_HEAPMODE 1
24#endif
25
26/*!
27* LEGACY_SUPPORT :
28* if set to 1+, ZSTD_decompress() can decode older formats (v0.1+)
29*/
30
31/*!
32 * MAXWINDOWSIZE_DEFAULT :
33 * maximum window size accepted by DStream __by default__.
34 * Frames requiring more memory will be rejected.
35 * It's possible to set a different limit using ZSTD_DCtx_setMaxWindowSize().
36 */
37#ifndef ZSTD_MAXWINDOWSIZE_DEFAULT
38# define ZSTD_MAXWINDOWSIZE_DEFAULT (((U32)1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT) + 1)
39#endif
40
41/*!
42 * NO_FORWARD_PROGRESS_MAX :
43 * maximum allowed nb of calls to ZSTD_decompressStream()
44 * without any forward progress
45 * (defined as: no byte read from input, and no byte flushed to output)
46 * before triggering an error.
47 */
48#ifndef ZSTD_NO_FORWARD_PROGRESS_MAX
49# define ZSTD_NO_FORWARD_PROGRESS_MAX 16
50#endif
51
52
53/*-*******************************************************
54* Dependencies
55*********************************************************/
56#include "../common/zstd_deps.h" /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */
57#include "../common/allocations.h" /* ZSTD_customMalloc, ZSTD_customCalloc, ZSTD_customFree */
58#include "../common/error_private.h"
59#include "../common/zstd_internal.h" /* blockProperties_t */
60#include "../common/mem.h" /* low level memory routines */
61#include "../common/bits.h" /* ZSTD_highbit32 */
62#define FSE_STATIC_LINKING_ONLY
63#include "../common/fse.h"
64#include "../common/huf.h"
65#include <linux/xxhash.h> /* xxh64_reset, xxh64_update, xxh64_digest, XXH64 */
66#include "zstd_decompress_internal.h" /* ZSTD_DCtx */
67#include "zstd_ddict.h" /* ZSTD_DDictDictContent */
68#include "zstd_decompress_block.h" /* ZSTD_decompressBlock_internal */
69
70
71
72
73/* ***********************************
74 * Multiple DDicts Hashset internals *
75 *************************************/
76
77#define DDICT_HASHSET_MAX_LOAD_FACTOR_COUNT_MULT 4
78#define DDICT_HASHSET_MAX_LOAD_FACTOR_SIZE_MULT 3 /* These two constants represent SIZE_MULT/COUNT_MULT load factor without using a float.
79 * Currently, that means a 0.75 load factor.
80 * So, if count * COUNT_MULT / size * SIZE_MULT != 0, then we've exceeded
81 * the load factor of the ddict hash set.
82 */
83
84#define DDICT_HASHSET_TABLE_BASE_SIZE 64
85#define DDICT_HASHSET_RESIZE_FACTOR 2
86
87/* Hash function to determine starting position of dict insertion within the table
88 * Returns an index between [0, hashSet->ddictPtrTableSize]
89 */
90static size_t ZSTD_DDictHashSet_getIndex(const ZSTD_DDictHashSet* hashSet, U32 dictID) {
91 const U64 hash = xxh64(input: &dictID, length: sizeof(U32), seed: 0);
92 /* DDict ptr table size is a multiple of 2, use size - 1 as mask to get index within [0, hashSet->ddictPtrTableSize) */
93 return hash & (hashSet->ddictPtrTableSize - 1);
94}
95
96/* Adds DDict to a hashset without resizing it.
97 * If inserting a DDict with a dictID that already exists in the set, replaces the one in the set.
98 * Returns 0 if successful, or a zstd error code if something went wrong.
99 */
100static size_t ZSTD_DDictHashSet_emplaceDDict(ZSTD_DDictHashSet* hashSet, const ZSTD_DDict* ddict) {
101 const U32 dictID = ZSTD_getDictID_fromDDict(ddict);
102 size_t idx = ZSTD_DDictHashSet_getIndex(hashSet, dictID);
103 const size_t idxRangeMask = hashSet->ddictPtrTableSize - 1;
104 RETURN_ERROR_IF(hashSet->ddictPtrCount == hashSet->ddictPtrTableSize, GENERIC, "Hash set is full!");
105 DEBUGLOG(4, "Hashed index: for dictID: %u is %zu", dictID, idx);
106 while (hashSet->ddictPtrTable[idx] != NULL) {
107 /* Replace existing ddict if inserting ddict with same dictID */
108 if (ZSTD_getDictID_fromDDict(ddict: hashSet->ddictPtrTable[idx]) == dictID) {
109 DEBUGLOG(4, "DictID already exists, replacing rather than adding");
110 hashSet->ddictPtrTable[idx] = ddict;
111 return 0;
112 }
113 idx &= idxRangeMask;
114 idx++;
115 }
116 DEBUGLOG(4, "Final idx after probing for dictID %u is: %zu", dictID, idx);
117 hashSet->ddictPtrTable[idx] = ddict;
118 hashSet->ddictPtrCount++;
119 return 0;
120}
121
122/* Expands hash table by factor of DDICT_HASHSET_RESIZE_FACTOR and
123 * rehashes all values, allocates new table, frees old table.
124 * Returns 0 on success, otherwise a zstd error code.
125 */
126static size_t ZSTD_DDictHashSet_expand(ZSTD_DDictHashSet* hashSet, ZSTD_customMem customMem) {
127 size_t newTableSize = hashSet->ddictPtrTableSize * DDICT_HASHSET_RESIZE_FACTOR;
128 const ZSTD_DDict** newTable = (const ZSTD_DDict**)ZSTD_customCalloc(size: sizeof(ZSTD_DDict*) * newTableSize, customMem);
129 const ZSTD_DDict** oldTable = hashSet->ddictPtrTable;
130 size_t oldTableSize = hashSet->ddictPtrTableSize;
131 size_t i;
132
133 DEBUGLOG(4, "Expanding DDict hash table! Old size: %zu new size: %zu", oldTableSize, newTableSize);
134 RETURN_ERROR_IF(!newTable, memory_allocation, "Expanded hashset allocation failed!");
135 hashSet->ddictPtrTable = newTable;
136 hashSet->ddictPtrTableSize = newTableSize;
137 hashSet->ddictPtrCount = 0;
138 for (i = 0; i < oldTableSize; ++i) {
139 if (oldTable[i] != NULL) {
140 FORWARD_IF_ERROR(ZSTD_DDictHashSet_emplaceDDict(hashSet, oldTable[i]), "");
141 }
142 }
143 ZSTD_customFree(ptr: (void*)oldTable, customMem);
144 DEBUGLOG(4, "Finished re-hash");
145 return 0;
146}
147
148/* Fetches a DDict with the given dictID
149 * Returns the ZSTD_DDict* with the requested dictID. If it doesn't exist, then returns NULL.
150 */
151static const ZSTD_DDict* ZSTD_DDictHashSet_getDDict(ZSTD_DDictHashSet* hashSet, U32 dictID) {
152 size_t idx = ZSTD_DDictHashSet_getIndex(hashSet, dictID);
153 const size_t idxRangeMask = hashSet->ddictPtrTableSize - 1;
154 DEBUGLOG(4, "Hashed index: for dictID: %u is %zu", dictID, idx);
155 for (;;) {
156 size_t currDictID = ZSTD_getDictID_fromDDict(ddict: hashSet->ddictPtrTable[idx]);
157 if (currDictID == dictID || currDictID == 0) {
158 /* currDictID == 0 implies a NULL ddict entry */
159 break;
160 } else {
161 idx &= idxRangeMask; /* Goes to start of table when we reach the end */
162 idx++;
163 }
164 }
165 DEBUGLOG(4, "Final idx after probing for dictID %u is: %zu", dictID, idx);
166 return hashSet->ddictPtrTable[idx];
167}
168
169/* Allocates space for and returns a ddict hash set
170 * The hash set's ZSTD_DDict* table has all values automatically set to NULL to begin with.
171 * Returns NULL if allocation failed.
172 */
173static ZSTD_DDictHashSet* ZSTD_createDDictHashSet(ZSTD_customMem customMem) {
174 ZSTD_DDictHashSet* ret = (ZSTD_DDictHashSet*)ZSTD_customMalloc(size: sizeof(ZSTD_DDictHashSet), customMem);
175 DEBUGLOG(4, "Allocating new hash set");
176 if (!ret)
177 return NULL;
178 ret->ddictPtrTable = (const ZSTD_DDict**)ZSTD_customCalloc(DDICT_HASHSET_TABLE_BASE_SIZE * sizeof(ZSTD_DDict*), customMem);
179 if (!ret->ddictPtrTable) {
180 ZSTD_customFree(ptr: ret, customMem);
181 return NULL;
182 }
183 ret->ddictPtrTableSize = DDICT_HASHSET_TABLE_BASE_SIZE;
184 ret->ddictPtrCount = 0;
185 return ret;
186}
187
188/* Frees the table of ZSTD_DDict* within a hashset, then frees the hashset itself.
189 * Note: The ZSTD_DDict* within the table are NOT freed.
190 */
191static void ZSTD_freeDDictHashSet(ZSTD_DDictHashSet* hashSet, ZSTD_customMem customMem) {
192 DEBUGLOG(4, "Freeing ddict hash set");
193 if (hashSet && hashSet->ddictPtrTable) {
194 ZSTD_customFree(ptr: (void*)hashSet->ddictPtrTable, customMem);
195 }
196 if (hashSet) {
197 ZSTD_customFree(ptr: hashSet, customMem);
198 }
199}
200
201/* Public function: Adds a DDict into the ZSTD_DDictHashSet, possibly triggering a resize of the hash set.
202 * Returns 0 on success, or a ZSTD error.
203 */
204static size_t ZSTD_DDictHashSet_addDDict(ZSTD_DDictHashSet* hashSet, const ZSTD_DDict* ddict, ZSTD_customMem customMem) {
205 DEBUGLOG(4, "Adding dict ID: %u to hashset with - Count: %zu Tablesize: %zu", ZSTD_getDictID_fromDDict(ddict), hashSet->ddictPtrCount, hashSet->ddictPtrTableSize);
206 if (hashSet->ddictPtrCount * DDICT_HASHSET_MAX_LOAD_FACTOR_COUNT_MULT / hashSet->ddictPtrTableSize * DDICT_HASHSET_MAX_LOAD_FACTOR_SIZE_MULT != 0) {
207 FORWARD_IF_ERROR(ZSTD_DDictHashSet_expand(hashSet, customMem), "");
208 }
209 FORWARD_IF_ERROR(ZSTD_DDictHashSet_emplaceDDict(hashSet, ddict), "");
210 return 0;
211}
212
213/*-*************************************************************
214* Context management
215***************************************************************/
216size_t ZSTD_sizeof_DCtx (const ZSTD_DCtx* dctx)
217{
218 if (dctx==NULL) return 0; /* support sizeof NULL */
219 return sizeof(*dctx)
220 + ZSTD_sizeof_DDict(ddict: dctx->ddictLocal)
221 + dctx->inBuffSize + dctx->outBuffSize;
222}
223
224size_t ZSTD_estimateDCtxSize(void) { return sizeof(ZSTD_DCtx); }
225
226
227static size_t ZSTD_startingInputLength(ZSTD_format_e format)
228{
229 size_t const startingInputLength = ZSTD_FRAMEHEADERSIZE_PREFIX(format);
230 /* only supports formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless */
231 assert( (format == ZSTD_f_zstd1) || (format == ZSTD_f_zstd1_magicless) );
232 return startingInputLength;
233}
234
235static void ZSTD_DCtx_resetParameters(ZSTD_DCtx* dctx)
236{
237 assert(dctx->streamStage == zdss_init);
238 dctx->format = ZSTD_f_zstd1;
239 dctx->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT;
240 dctx->outBufferMode = ZSTD_bm_buffered;
241 dctx->forceIgnoreChecksum = ZSTD_d_validateChecksum;
242 dctx->refMultipleDDicts = ZSTD_rmd_refSingleDDict;
243 dctx->disableHufAsm = 0;
244 dctx->maxBlockSizeParam = 0;
245}
246
247static void ZSTD_initDCtx_internal(ZSTD_DCtx* dctx)
248{
249 dctx->staticSize = 0;
250 dctx->ddict = NULL;
251 dctx->ddictLocal = NULL;
252 dctx->dictEnd = NULL;
253 dctx->ddictIsCold = 0;
254 dctx->dictUses = ZSTD_dont_use;
255 dctx->inBuff = NULL;
256 dctx->inBuffSize = 0;
257 dctx->outBuffSize = 0;
258 dctx->streamStage = zdss_init;
259 dctx->noForwardProgress = 0;
260 dctx->oversizedDuration = 0;
261 dctx->isFrameDecompression = 1;
262#if DYNAMIC_BMI2
263 dctx->bmi2 = ZSTD_cpuSupportsBmi2();
264#endif
265 dctx->ddictSet = NULL;
266 ZSTD_DCtx_resetParameters(dctx);
267#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
268 dctx->dictContentEndForFuzzing = NULL;
269#endif
270}
271
272ZSTD_DCtx* ZSTD_initStaticDCtx(void *workspace, size_t workspaceSize)
273{
274 ZSTD_DCtx* const dctx = (ZSTD_DCtx*) workspace;
275
276 if ((size_t)workspace & 7) return NULL; /* 8-aligned */
277 if (workspaceSize < sizeof(ZSTD_DCtx)) return NULL; /* minimum size */
278
279 ZSTD_initDCtx_internal(dctx);
280 dctx->staticSize = workspaceSize;
281 dctx->inBuff = (char*)(dctx+1);
282 return dctx;
283}
284
285static ZSTD_DCtx* ZSTD_createDCtx_internal(ZSTD_customMem customMem) {
286 if ((!customMem.customAlloc) ^ (!customMem.customFree)) return NULL;
287
288 { ZSTD_DCtx* const dctx = (ZSTD_DCtx*)ZSTD_customMalloc(size: sizeof(*dctx), customMem);
289 if (!dctx) return NULL;
290 dctx->customMem = customMem;
291 ZSTD_initDCtx_internal(dctx);
292 return dctx;
293 }
294}
295
296ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
297{
298 return ZSTD_createDCtx_internal(customMem);
299}
300
301ZSTD_DCtx* ZSTD_createDCtx(void)
302{
303 DEBUGLOG(3, "ZSTD_createDCtx");
304 return ZSTD_createDCtx_internal(customMem: ZSTD_defaultCMem);
305}
306
307static void ZSTD_clearDict(ZSTD_DCtx* dctx)
308{
309 ZSTD_freeDDict(ddict: dctx->ddictLocal);
310 dctx->ddictLocal = NULL;
311 dctx->ddict = NULL;
312 dctx->dictUses = ZSTD_dont_use;
313}
314
315size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx)
316{
317 if (dctx==NULL) return 0; /* support free on NULL */
318 RETURN_ERROR_IF(dctx->staticSize, memory_allocation, "not compatible with static DCtx");
319 { ZSTD_customMem const cMem = dctx->customMem;
320 ZSTD_clearDict(dctx);
321 ZSTD_customFree(ptr: dctx->inBuff, customMem: cMem);
322 dctx->inBuff = NULL;
323 if (dctx->ddictSet) {
324 ZSTD_freeDDictHashSet(hashSet: dctx->ddictSet, customMem: cMem);
325 dctx->ddictSet = NULL;
326 }
327 ZSTD_customFree(ptr: dctx, customMem: cMem);
328 return 0;
329 }
330}
331
332/* no longer useful */
333void ZSTD_copyDCtx(ZSTD_DCtx* dstDCtx, const ZSTD_DCtx* srcDCtx)
334{
335 size_t const toCopy = (size_t)((char*)(&dstDCtx->inBuff) - (char*)dstDCtx);
336 ZSTD_memcpy(dstDCtx, srcDCtx, toCopy); /* no need to copy workspace */
337}
338
339/* Given a dctx with a digested frame params, re-selects the correct ZSTD_DDict based on
340 * the requested dict ID from the frame. If there exists a reference to the correct ZSTD_DDict, then
341 * accordingly sets the ddict to be used to decompress the frame.
342 *
343 * If no DDict is found, then no action is taken, and the ZSTD_DCtx::ddict remains as-is.
344 *
345 * ZSTD_d_refMultipleDDicts must be enabled for this function to be called.
346 */
347static void ZSTD_DCtx_selectFrameDDict(ZSTD_DCtx* dctx) {
348 assert(dctx->refMultipleDDicts && dctx->ddictSet);
349 DEBUGLOG(4, "Adjusting DDict based on requested dict ID from frame");
350 if (dctx->ddict) {
351 const ZSTD_DDict* frameDDict = ZSTD_DDictHashSet_getDDict(hashSet: dctx->ddictSet, dictID: dctx->fParams.dictID);
352 if (frameDDict) {
353 DEBUGLOG(4, "DDict found!");
354 ZSTD_clearDict(dctx);
355 dctx->dictID = dctx->fParams.dictID;
356 dctx->ddict = frameDDict;
357 dctx->dictUses = ZSTD_use_indefinitely;
358 }
359 }
360}
361
362
363/*-*************************************************************
364 * Frame header decoding
365 ***************************************************************/
366
367/*! ZSTD_isFrame() :
368 * Tells if the content of `buffer` starts with a valid Frame Identifier.
369 * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0.
370 * Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled.
371 * Note 3 : Skippable Frame Identifiers are considered valid. */
372unsigned ZSTD_isFrame(const void* buffer, size_t size)
373{
374 if (size < ZSTD_FRAMEIDSIZE) return 0;
375 { U32 const magic = MEM_readLE32(memPtr: buffer);
376 if (magic == ZSTD_MAGICNUMBER) return 1;
377 if ((magic & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) return 1;
378 }
379 return 0;
380}
381
382/*! ZSTD_isSkippableFrame() :
383 * Tells if the content of `buffer` starts with a valid Frame Identifier for a skippable frame.
384 * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0.
385 */
386unsigned ZSTD_isSkippableFrame(const void* buffer, size_t size)
387{
388 if (size < ZSTD_FRAMEIDSIZE) return 0;
389 { U32 const magic = MEM_readLE32(memPtr: buffer);
390 if ((magic & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) return 1;
391 }
392 return 0;
393}
394
395/* ZSTD_frameHeaderSize_internal() :
396 * srcSize must be large enough to reach header size fields.
397 * note : only works for formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless.
398 * @return : size of the Frame Header
399 * or an error code, which can be tested with ZSTD_isError() */
400static size_t ZSTD_frameHeaderSize_internal(const void* src, size_t srcSize, ZSTD_format_e format)
401{
402 size_t const minInputSize = ZSTD_startingInputLength(format);
403 RETURN_ERROR_IF(srcSize < minInputSize, srcSize_wrong, "");
404
405 { BYTE const fhd = ((const BYTE*)src)[minInputSize-1];
406 U32 const dictID= fhd & 3;
407 U32 const singleSegment = (fhd >> 5) & 1;
408 U32 const fcsId = fhd >> 6;
409 return minInputSize + !singleSegment
410 + ZSTD_did_fieldSize[dictID] + ZSTD_fcs_fieldSize[fcsId]
411 + (singleSegment && !fcsId);
412 }
413}
414
415/* ZSTD_frameHeaderSize() :
416 * srcSize must be >= ZSTD_frameHeaderSize_prefix.
417 * @return : size of the Frame Header,
418 * or an error code (if srcSize is too small) */
419size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize)
420{
421 return ZSTD_frameHeaderSize_internal(src, srcSize, format: ZSTD_f_zstd1);
422}
423
424
425/* ZSTD_getFrameHeader_advanced() :
426 * decode Frame Header, or require larger `srcSize`.
427 * note : only works for formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless
428 * @return : 0, `zfhPtr` is correctly filled,
429 * >0, `srcSize` is too small, value is wanted `srcSize` amount,
430** or an error code, which can be tested using ZSTD_isError() */
431size_t ZSTD_getFrameHeader_advanced(ZSTD_FrameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format)
432{
433 const BYTE* ip = (const BYTE*)src;
434 size_t const minInputSize = ZSTD_startingInputLength(format);
435
436 DEBUGLOG(5, "ZSTD_getFrameHeader_advanced: minInputSize = %zu, srcSize = %zu", minInputSize, srcSize);
437
438 if (srcSize > 0) {
439 /* note : technically could be considered an assert(), since it's an invalid entry */
440 RETURN_ERROR_IF(src==NULL, GENERIC, "invalid parameter : src==NULL, but srcSize>0");
441 }
442 if (srcSize < minInputSize) {
443 if (srcSize > 0 && format != ZSTD_f_zstd1_magicless) {
444 /* when receiving less than @minInputSize bytes,
445 * control these bytes at least correspond to a supported magic number
446 * in order to error out early if they don't.
447 **/
448 size_t const toCopy = MIN(4, srcSize);
449 unsigned char hbuf[4]; MEM_writeLE32(memPtr: hbuf, ZSTD_MAGICNUMBER);
450 assert(src != NULL);
451 ZSTD_memcpy(hbuf, src, toCopy);
452 if ( MEM_readLE32(memPtr: hbuf) != ZSTD_MAGICNUMBER ) {
453 /* not a zstd frame : let's check if it's a skippable frame */
454 MEM_writeLE32(memPtr: hbuf, ZSTD_MAGIC_SKIPPABLE_START);
455 ZSTD_memcpy(hbuf, src, toCopy);
456 if ((MEM_readLE32(memPtr: hbuf) & ZSTD_MAGIC_SKIPPABLE_MASK) != ZSTD_MAGIC_SKIPPABLE_START) {
457 RETURN_ERROR(prefix_unknown,
458 "first bytes don't correspond to any supported magic number");
459 } } }
460 return minInputSize;
461 }
462
463 ZSTD_memset(zfhPtr, 0, sizeof(*zfhPtr)); /* not strictly necessary, but static analyzers may not understand that zfhPtr will be read only if return value is zero, since they are 2 different signals */
464 if ( (format != ZSTD_f_zstd1_magicless)
465 && (MEM_readLE32(memPtr: src) != ZSTD_MAGICNUMBER) ) {
466 if ((MEM_readLE32(memPtr: src) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) {
467 /* skippable frame */
468 if (srcSize < ZSTD_SKIPPABLEHEADERSIZE)
469 return ZSTD_SKIPPABLEHEADERSIZE; /* magic number + frame length */
470 ZSTD_memset(zfhPtr, 0, sizeof(*zfhPtr));
471 zfhPtr->frameType = ZSTD_skippableFrame;
472 zfhPtr->dictID = MEM_readLE32(memPtr: src) - ZSTD_MAGIC_SKIPPABLE_START;
473 zfhPtr->headerSize = ZSTD_SKIPPABLEHEADERSIZE;
474 zfhPtr->frameContentSize = MEM_readLE32(memPtr: (const char *)src + ZSTD_FRAMEIDSIZE);
475 return 0;
476 }
477 RETURN_ERROR(prefix_unknown, "");
478 }
479
480 /* ensure there is enough `srcSize` to fully read/decode frame header */
481 { size_t const fhsize = ZSTD_frameHeaderSize_internal(src, srcSize, format);
482 if (srcSize < fhsize) return fhsize;
483 zfhPtr->headerSize = (U32)fhsize;
484 }
485
486 { BYTE const fhdByte = ip[minInputSize-1];
487 size_t pos = minInputSize;
488 U32 const dictIDSizeCode = fhdByte&3;
489 U32 const checksumFlag = (fhdByte>>2)&1;
490 U32 const singleSegment = (fhdByte>>5)&1;
491 U32 const fcsID = fhdByte>>6;
492 U64 windowSize = 0;
493 U32 dictID = 0;
494 U64 frameContentSize = ZSTD_CONTENTSIZE_UNKNOWN;
495 RETURN_ERROR_IF((fhdByte & 0x08) != 0, frameParameter_unsupported,
496 "reserved bits, must be zero");
497
498 if (!singleSegment) {
499 BYTE const wlByte = ip[pos++];
500 U32 const windowLog = (wlByte >> 3) + ZSTD_WINDOWLOG_ABSOLUTEMIN;
501 RETURN_ERROR_IF(windowLog > ZSTD_WINDOWLOG_MAX, frameParameter_windowTooLarge, "");
502 windowSize = (1ULL << windowLog);
503 windowSize += (windowSize >> 3) * (wlByte&7);
504 }
505 switch(dictIDSizeCode)
506 {
507 default:
508 assert(0); /* impossible */
509 ZSTD_FALLTHROUGH;
510 case 0 : break;
511 case 1 : dictID = ip[pos]; pos++; break;
512 case 2 : dictID = MEM_readLE16(memPtr: ip+pos); pos+=2; break;
513 case 3 : dictID = MEM_readLE32(memPtr: ip+pos); pos+=4; break;
514 }
515 switch(fcsID)
516 {
517 default:
518 assert(0); /* impossible */
519 ZSTD_FALLTHROUGH;
520 case 0 : if (singleSegment) frameContentSize = ip[pos]; break;
521 case 1 : frameContentSize = MEM_readLE16(memPtr: ip+pos)+256; break;
522 case 2 : frameContentSize = MEM_readLE32(memPtr: ip+pos); break;
523 case 3 : frameContentSize = MEM_readLE64(memPtr: ip+pos); break;
524 }
525 if (singleSegment) windowSize = frameContentSize;
526
527 zfhPtr->frameType = ZSTD_frame;
528 zfhPtr->frameContentSize = frameContentSize;
529 zfhPtr->windowSize = windowSize;
530 zfhPtr->blockSizeMax = (unsigned) MIN(windowSize, ZSTD_BLOCKSIZE_MAX);
531 zfhPtr->dictID = dictID;
532 zfhPtr->checksumFlag = checksumFlag;
533 }
534 return 0;
535}
536
537/* ZSTD_getFrameHeader() :
538 * decode Frame Header, or require larger `srcSize`.
539 * note : this function does not consume input, it only reads it.
540 * @return : 0, `zfhPtr` is correctly filled,
541 * >0, `srcSize` is too small, value is wanted `srcSize` amount,
542 * or an error code, which can be tested using ZSTD_isError() */
543size_t ZSTD_getFrameHeader(ZSTD_FrameHeader* zfhPtr, const void* src, size_t srcSize)
544{
545 return ZSTD_getFrameHeader_advanced(zfhPtr, src, srcSize, format: ZSTD_f_zstd1);
546}
547
548/* ZSTD_getFrameContentSize() :
549 * compatible with legacy mode
550 * @return : decompressed size of the single frame pointed to be `src` if known, otherwise
551 * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
552 * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) */
553unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize)
554{
555 { ZSTD_FrameHeader zfh;
556 if (ZSTD_getFrameHeader(zfhPtr: &zfh, src, srcSize) != 0)
557 return ZSTD_CONTENTSIZE_ERROR;
558 if (zfh.frameType == ZSTD_skippableFrame) {
559 return 0;
560 } else {
561 return zfh.frameContentSize;
562 } }
563}
564
565static size_t readSkippableFrameSize(void const* src, size_t srcSize)
566{
567 size_t const skippableHeaderSize = ZSTD_SKIPPABLEHEADERSIZE;
568 U32 sizeU32;
569
570 RETURN_ERROR_IF(srcSize < ZSTD_SKIPPABLEHEADERSIZE, srcSize_wrong, "");
571
572 sizeU32 = MEM_readLE32(memPtr: (BYTE const*)src + ZSTD_FRAMEIDSIZE);
573 RETURN_ERROR_IF((U32)(sizeU32 + ZSTD_SKIPPABLEHEADERSIZE) < sizeU32,
574 frameParameter_unsupported, "");
575 { size_t const skippableSize = skippableHeaderSize + sizeU32;
576 RETURN_ERROR_IF(skippableSize > srcSize, srcSize_wrong, "");
577 return skippableSize;
578 }
579}
580
581/*! ZSTD_readSkippableFrame() :
582 * Retrieves content of a skippable frame, and writes it to dst buffer.
583 *
584 * The parameter magicVariant will receive the magicVariant that was supplied when the frame was written,
585 * i.e. magicNumber - ZSTD_MAGIC_SKIPPABLE_START. This can be NULL if the caller is not interested
586 * in the magicVariant.
587 *
588 * Returns an error if destination buffer is not large enough, or if this is not a valid skippable frame.
589 *
590 * @return : number of bytes written or a ZSTD error.
591 */
592size_t ZSTD_readSkippableFrame(void* dst, size_t dstCapacity,
593 unsigned* magicVariant, /* optional, can be NULL */
594 const void* src, size_t srcSize)
595{
596 RETURN_ERROR_IF(srcSize < ZSTD_SKIPPABLEHEADERSIZE, srcSize_wrong, "");
597
598 { U32 const magicNumber = MEM_readLE32(memPtr: src);
599 size_t skippableFrameSize = readSkippableFrameSize(src, srcSize);
600 size_t skippableContentSize = skippableFrameSize - ZSTD_SKIPPABLEHEADERSIZE;
601
602 /* check input validity */
603 RETURN_ERROR_IF(!ZSTD_isSkippableFrame(src, srcSize), frameParameter_unsupported, "");
604 RETURN_ERROR_IF(skippableFrameSize < ZSTD_SKIPPABLEHEADERSIZE || skippableFrameSize > srcSize, srcSize_wrong, "");
605 RETURN_ERROR_IF(skippableContentSize > dstCapacity, dstSize_tooSmall, "");
606
607 /* deliver payload */
608 if (skippableContentSize > 0 && dst != NULL)
609 ZSTD_memcpy(dst, (const BYTE *)src + ZSTD_SKIPPABLEHEADERSIZE, skippableContentSize);
610 if (magicVariant != NULL)
611 *magicVariant = magicNumber - ZSTD_MAGIC_SKIPPABLE_START;
612 return skippableContentSize;
613 }
614}
615
616/* ZSTD_findDecompressedSize() :
617 * `srcSize` must be the exact length of some number of ZSTD compressed and/or
618 * skippable frames
619 * note: compatible with legacy mode
620 * @return : decompressed size of the frames contained */
621unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize)
622{
623 unsigned long long totalDstSize = 0;
624
625 while (srcSize >= ZSTD_startingInputLength(format: ZSTD_f_zstd1)) {
626 U32 const magicNumber = MEM_readLE32(memPtr: src);
627
628 if ((magicNumber & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) {
629 size_t const skippableSize = readSkippableFrameSize(src, srcSize);
630 if (ZSTD_isError(code: skippableSize)) return ZSTD_CONTENTSIZE_ERROR;
631 assert(skippableSize <= srcSize);
632
633 src = (const BYTE *)src + skippableSize;
634 srcSize -= skippableSize;
635 continue;
636 }
637
638 { unsigned long long const fcs = ZSTD_getFrameContentSize(src, srcSize);
639 if (fcs >= ZSTD_CONTENTSIZE_ERROR) return fcs;
640
641 if (totalDstSize + fcs < totalDstSize)
642 return ZSTD_CONTENTSIZE_ERROR; /* check for overflow */
643 totalDstSize += fcs;
644 }
645 /* skip to next frame */
646 { size_t const frameSrcSize = ZSTD_findFrameCompressedSize(src, srcSize);
647 if (ZSTD_isError(code: frameSrcSize)) return ZSTD_CONTENTSIZE_ERROR;
648 assert(frameSrcSize <= srcSize);
649
650 src = (const BYTE *)src + frameSrcSize;
651 srcSize -= frameSrcSize;
652 }
653 } /* while (srcSize >= ZSTD_frameHeaderSize_prefix) */
654
655 if (srcSize) return ZSTD_CONTENTSIZE_ERROR;
656
657 return totalDstSize;
658}
659
660/* ZSTD_getDecompressedSize() :
661 * compatible with legacy mode
662 * @return : decompressed size if known, 0 otherwise
663 note : 0 can mean any of the following :
664 - frame content is empty
665 - decompressed size field is not present in frame header
666 - frame header unknown / not supported
667 - frame header not complete (`srcSize` too small) */
668unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize)
669{
670 unsigned long long const ret = ZSTD_getFrameContentSize(src, srcSize);
671 ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_ERROR < ZSTD_CONTENTSIZE_UNKNOWN);
672 return (ret >= ZSTD_CONTENTSIZE_ERROR) ? 0 : ret;
673}
674
675
676/* ZSTD_decodeFrameHeader() :
677 * `headerSize` must be the size provided by ZSTD_frameHeaderSize().
678 * If multiple DDict references are enabled, also will choose the correct DDict to use.
679 * @return : 0 if success, or an error code, which can be tested using ZSTD_isError() */
680static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx* dctx, const void* src, size_t headerSize)
681{
682 size_t const result = ZSTD_getFrameHeader_advanced(zfhPtr: &(dctx->fParams), src, srcSize: headerSize, format: dctx->format);
683 if (ZSTD_isError(code: result)) return result; /* invalid header */
684 RETURN_ERROR_IF(result>0, srcSize_wrong, "headerSize too small");
685
686 /* Reference DDict requested by frame if dctx references multiple ddicts */
687 if (dctx->refMultipleDDicts == ZSTD_rmd_refMultipleDDicts && dctx->ddictSet) {
688 ZSTD_DCtx_selectFrameDDict(dctx);
689 }
690
691#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
692 /* Skip the dictID check in fuzzing mode, because it makes the search
693 * harder.
694 */
695 RETURN_ERROR_IF(dctx->fParams.dictID && (dctx->dictID != dctx->fParams.dictID),
696 dictionary_wrong, "");
697#endif
698 dctx->validateChecksum = (dctx->fParams.checksumFlag && !dctx->forceIgnoreChecksum) ? 1 : 0;
699 if (dctx->validateChecksum) xxh64_reset(state: &dctx->xxhState, seed: 0);
700 dctx->processedCSize += headerSize;
701 return 0;
702}
703
704static ZSTD_frameSizeInfo ZSTD_errorFrameSizeInfo(size_t ret)
705{
706 ZSTD_frameSizeInfo frameSizeInfo;
707 frameSizeInfo.compressedSize = ret;
708 frameSizeInfo.decompressedBound = ZSTD_CONTENTSIZE_ERROR;
709 return frameSizeInfo;
710}
711
712static ZSTD_frameSizeInfo ZSTD_findFrameSizeInfo(const void* src, size_t srcSize, ZSTD_format_e format)
713{
714 ZSTD_frameSizeInfo frameSizeInfo;
715 ZSTD_memset(&frameSizeInfo, 0, sizeof(ZSTD_frameSizeInfo));
716
717
718 if (format == ZSTD_f_zstd1 && (srcSize >= ZSTD_SKIPPABLEHEADERSIZE)
719 && (MEM_readLE32(memPtr: src) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) {
720 frameSizeInfo.compressedSize = readSkippableFrameSize(src, srcSize);
721 assert(ZSTD_isError(frameSizeInfo.compressedSize) ||
722 frameSizeInfo.compressedSize <= srcSize);
723 return frameSizeInfo;
724 } else {
725 const BYTE* ip = (const BYTE*)src;
726 const BYTE* const ipstart = ip;
727 size_t remainingSize = srcSize;
728 size_t nbBlocks = 0;
729 ZSTD_FrameHeader zfh;
730
731 /* Extract Frame Header */
732 { size_t const ret = ZSTD_getFrameHeader_advanced(zfhPtr: &zfh, src, srcSize, format);
733 if (ZSTD_isError(code: ret))
734 return ZSTD_errorFrameSizeInfo(ret);
735 if (ret > 0)
736 return ZSTD_errorFrameSizeInfo(ERROR(srcSize_wrong));
737 }
738
739 ip += zfh.headerSize;
740 remainingSize -= zfh.headerSize;
741
742 /* Iterate over each block */
743 while (1) {
744 blockProperties_t blockProperties;
745 size_t const cBlockSize = ZSTD_getcBlockSize(src: ip, srcSize: remainingSize, bpPtr: &blockProperties);
746 if (ZSTD_isError(code: cBlockSize))
747 return ZSTD_errorFrameSizeInfo(ret: cBlockSize);
748
749 if (ZSTD_blockHeaderSize + cBlockSize > remainingSize)
750 return ZSTD_errorFrameSizeInfo(ERROR(srcSize_wrong));
751
752 ip += ZSTD_blockHeaderSize + cBlockSize;
753 remainingSize -= ZSTD_blockHeaderSize + cBlockSize;
754 nbBlocks++;
755
756 if (blockProperties.lastBlock) break;
757 }
758
759 /* Final frame content checksum */
760 if (zfh.checksumFlag) {
761 if (remainingSize < 4)
762 return ZSTD_errorFrameSizeInfo(ERROR(srcSize_wrong));
763 ip += 4;
764 }
765
766 frameSizeInfo.nbBlocks = nbBlocks;
767 frameSizeInfo.compressedSize = (size_t)(ip - ipstart);
768 frameSizeInfo.decompressedBound = (zfh.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN)
769 ? zfh.frameContentSize
770 : (unsigned long long)nbBlocks * zfh.blockSizeMax;
771 return frameSizeInfo;
772 }
773}
774
775static size_t ZSTD_findFrameCompressedSize_advanced(const void *src, size_t srcSize, ZSTD_format_e format) {
776 ZSTD_frameSizeInfo const frameSizeInfo = ZSTD_findFrameSizeInfo(src, srcSize, format);
777 return frameSizeInfo.compressedSize;
778}
779
780/* ZSTD_findFrameCompressedSize() :
781 * See docs in zstd.h
782 * Note: compatible with legacy mode */
783size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize)
784{
785 return ZSTD_findFrameCompressedSize_advanced(src, srcSize, format: ZSTD_f_zstd1);
786}
787
788/* ZSTD_decompressBound() :
789 * compatible with legacy mode
790 * `src` must point to the start of a ZSTD frame or a skippable frame
791 * `srcSize` must be at least as large as the frame contained
792 * @return : the maximum decompressed size of the compressed source
793 */
794unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize)
795{
796 unsigned long long bound = 0;
797 /* Iterate over each frame */
798 while (srcSize > 0) {
799 ZSTD_frameSizeInfo const frameSizeInfo = ZSTD_findFrameSizeInfo(src, srcSize, format: ZSTD_f_zstd1);
800 size_t const compressedSize = frameSizeInfo.compressedSize;
801 unsigned long long const decompressedBound = frameSizeInfo.decompressedBound;
802 if (ZSTD_isError(code: compressedSize) || decompressedBound == ZSTD_CONTENTSIZE_ERROR)
803 return ZSTD_CONTENTSIZE_ERROR;
804 assert(srcSize >= compressedSize);
805 src = (const BYTE*)src + compressedSize;
806 srcSize -= compressedSize;
807 bound += decompressedBound;
808 }
809 return bound;
810}
811
812size_t ZSTD_decompressionMargin(void const* src, size_t srcSize)
813{
814 size_t margin = 0;
815 unsigned maxBlockSize = 0;
816
817 /* Iterate over each frame */
818 while (srcSize > 0) {
819 ZSTD_frameSizeInfo const frameSizeInfo = ZSTD_findFrameSizeInfo(src, srcSize, format: ZSTD_f_zstd1);
820 size_t const compressedSize = frameSizeInfo.compressedSize;
821 unsigned long long const decompressedBound = frameSizeInfo.decompressedBound;
822 ZSTD_FrameHeader zfh;
823
824 FORWARD_IF_ERROR(ZSTD_getFrameHeader(&zfh, src, srcSize), "");
825 if (ZSTD_isError(code: compressedSize) || decompressedBound == ZSTD_CONTENTSIZE_ERROR)
826 return ERROR(corruption_detected);
827
828 if (zfh.frameType == ZSTD_frame) {
829 /* Add the frame header to our margin */
830 margin += zfh.headerSize;
831 /* Add the checksum to our margin */
832 margin += zfh.checksumFlag ? 4 : 0;
833 /* Add 3 bytes per block */
834 margin += 3 * frameSizeInfo.nbBlocks;
835
836 /* Compute the max block size */
837 maxBlockSize = MAX(maxBlockSize, zfh.blockSizeMax);
838 } else {
839 assert(zfh.frameType == ZSTD_skippableFrame);
840 /* Add the entire skippable frame size to our margin. */
841 margin += compressedSize;
842 }
843
844 assert(srcSize >= compressedSize);
845 src = (const BYTE*)src + compressedSize;
846 srcSize -= compressedSize;
847 }
848
849 /* Add the max block size back to the margin. */
850 margin += maxBlockSize;
851
852 return margin;
853}
854
855/*-*************************************************************
856 * Frame decoding
857 ***************************************************************/
858
859/* ZSTD_insertBlock() :
860 * insert `src` block into `dctx` history. Useful to track uncompressed blocks. */
861size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize)
862{
863 DEBUGLOG(5, "ZSTD_insertBlock: %u bytes", (unsigned)blockSize);
864 ZSTD_checkContinuity(dctx, dst: blockStart, dstSize: blockSize);
865 dctx->previousDstEnd = (const char*)blockStart + blockSize;
866 return blockSize;
867}
868
869
870static size_t ZSTD_copyRawBlock(void* dst, size_t dstCapacity,
871 const void* src, size_t srcSize)
872{
873 DEBUGLOG(5, "ZSTD_copyRawBlock");
874 RETURN_ERROR_IF(srcSize > dstCapacity, dstSize_tooSmall, "");
875 if (dst == NULL) {
876 if (srcSize == 0) return 0;
877 RETURN_ERROR(dstBuffer_null, "");
878 }
879 ZSTD_memmove(dst, src, srcSize);
880 return srcSize;
881}
882
883static size_t ZSTD_setRleBlock(void* dst, size_t dstCapacity,
884 BYTE b,
885 size_t regenSize)
886{
887 RETURN_ERROR_IF(regenSize > dstCapacity, dstSize_tooSmall, "");
888 if (dst == NULL) {
889 if (regenSize == 0) return 0;
890 RETURN_ERROR(dstBuffer_null, "");
891 }
892 ZSTD_memset(dst, b, regenSize);
893 return regenSize;
894}
895
896static void ZSTD_DCtx_trace_end(ZSTD_DCtx const* dctx, U64 uncompressedSize, U64 compressedSize, int streaming)
897{
898 (void)dctx;
899 (void)uncompressedSize;
900 (void)compressedSize;
901 (void)streaming;
902}
903
904
905/*! ZSTD_decompressFrame() :
906 * @dctx must be properly initialized
907 * will update *srcPtr and *srcSizePtr,
908 * to make *srcPtr progress by one frame. */
909static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
910 void* dst, size_t dstCapacity,
911 const void** srcPtr, size_t *srcSizePtr)
912{
913 const BYTE* const istart = (const BYTE*)(*srcPtr);
914 const BYTE* ip = istart;
915 BYTE* const ostart = (BYTE*)dst;
916 BYTE* const oend = dstCapacity != 0 ? ostart + dstCapacity : ostart;
917 BYTE* op = ostart;
918 size_t remainingSrcSize = *srcSizePtr;
919
920 DEBUGLOG(4, "ZSTD_decompressFrame (srcSize:%i)", (int)*srcSizePtr);
921
922 /* check */
923 RETURN_ERROR_IF(
924 remainingSrcSize < ZSTD_FRAMEHEADERSIZE_MIN(dctx->format)+ZSTD_blockHeaderSize,
925 srcSize_wrong, "");
926
927 /* Frame Header */
928 { size_t const frameHeaderSize = ZSTD_frameHeaderSize_internal(
929 src: ip, ZSTD_FRAMEHEADERSIZE_PREFIX(dctx->format), format: dctx->format);
930 if (ZSTD_isError(code: frameHeaderSize)) return frameHeaderSize;
931 RETURN_ERROR_IF(remainingSrcSize < frameHeaderSize+ZSTD_blockHeaderSize,
932 srcSize_wrong, "");
933 FORWARD_IF_ERROR( ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize) , "");
934 ip += frameHeaderSize; remainingSrcSize -= frameHeaderSize;
935 }
936
937 /* Shrink the blockSizeMax if enabled */
938 if (dctx->maxBlockSizeParam != 0)
939 dctx->fParams.blockSizeMax = MIN(dctx->fParams.blockSizeMax, (unsigned)dctx->maxBlockSizeParam);
940
941 /* Loop on each block */
942 while (1) {
943 BYTE* oBlockEnd = oend;
944 size_t decodedSize;
945 blockProperties_t blockProperties;
946 size_t const cBlockSize = ZSTD_getcBlockSize(src: ip, srcSize: remainingSrcSize, bpPtr: &blockProperties);
947 if (ZSTD_isError(code: cBlockSize)) return cBlockSize;
948
949 ip += ZSTD_blockHeaderSize;
950 remainingSrcSize -= ZSTD_blockHeaderSize;
951 RETURN_ERROR_IF(cBlockSize > remainingSrcSize, srcSize_wrong, "");
952
953 if (ip >= op && ip < oBlockEnd) {
954 /* We are decompressing in-place. Limit the output pointer so that we
955 * don't overwrite the block that we are currently reading. This will
956 * fail decompression if the input & output pointers aren't spaced
957 * far enough apart.
958 *
959 * This is important to set, even when the pointers are far enough
960 * apart, because ZSTD_decompressBlock_internal() can decide to store
961 * literals in the output buffer, after the block it is decompressing.
962 * Since we don't want anything to overwrite our input, we have to tell
963 * ZSTD_decompressBlock_internal to never write past ip.
964 *
965 * See ZSTD_allocateLiteralsBuffer() for reference.
966 */
967 oBlockEnd = op + (ip - op);
968 }
969
970 switch(blockProperties.blockType)
971 {
972 case bt_compressed:
973 assert(dctx->isFrameDecompression == 1);
974 decodedSize = ZSTD_decompressBlock_internal(dctx, dst: op, dstCapacity: (size_t)(oBlockEnd-op), src: ip, srcSize: cBlockSize, streaming: not_streaming);
975 break;
976 case bt_raw :
977 /* Use oend instead of oBlockEnd because this function is safe to overlap. It uses memmove. */
978 decodedSize = ZSTD_copyRawBlock(dst: op, dstCapacity: (size_t)(oend-op), src: ip, srcSize: cBlockSize);
979 break;
980 case bt_rle :
981 decodedSize = ZSTD_setRleBlock(dst: op, dstCapacity: (size_t)(oBlockEnd-op), b: *ip, regenSize: blockProperties.origSize);
982 break;
983 case bt_reserved :
984 default:
985 RETURN_ERROR(corruption_detected, "invalid block type");
986 }
987 FORWARD_IF_ERROR(decodedSize, "Block decompression failure");
988 DEBUGLOG(5, "Decompressed block of dSize = %u", (unsigned)decodedSize);
989 if (dctx->validateChecksum) {
990 xxh64_update(state: &dctx->xxhState, input: op, length: decodedSize);
991 }
992 if (decodedSize) /* support dst = NULL,0 */ {
993 op += decodedSize;
994 }
995 assert(ip != NULL);
996 ip += cBlockSize;
997 remainingSrcSize -= cBlockSize;
998 if (blockProperties.lastBlock) break;
999 }
1000
1001 if (dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN) {
1002 RETURN_ERROR_IF((U64)(op-ostart) != dctx->fParams.frameContentSize,
1003 corruption_detected, "");
1004 }
1005 if (dctx->fParams.checksumFlag) { /* Frame content checksum verification */
1006 RETURN_ERROR_IF(remainingSrcSize<4, checksum_wrong, "");
1007 if (!dctx->forceIgnoreChecksum) {
1008 U32 const checkCalc = (U32)xxh64_digest(state: &dctx->xxhState);
1009 U32 checkRead;
1010 checkRead = MEM_readLE32(memPtr: ip);
1011 RETURN_ERROR_IF(checkRead != checkCalc, checksum_wrong, "");
1012 }
1013 ip += 4;
1014 remainingSrcSize -= 4;
1015 }
1016 ZSTD_DCtx_trace_end(dctx, uncompressedSize: (U64)(op-ostart), compressedSize: (U64)(ip-istart), /* streaming */ 0);
1017 /* Allow caller to get size read */
1018 DEBUGLOG(4, "ZSTD_decompressFrame: decompressed frame of size %i, consuming %i bytes of input", (int)(op-ostart), (int)(ip - (const BYTE*)*srcPtr));
1019 *srcPtr = ip;
1020 *srcSizePtr = remainingSrcSize;
1021 return (size_t)(op-ostart);
1022}
1023
1024static
1025ZSTD_ALLOW_POINTER_OVERFLOW_ATTR
1026size_t ZSTD_decompressMultiFrame(ZSTD_DCtx* dctx,
1027 void* dst, size_t dstCapacity,
1028 const void* src, size_t srcSize,
1029 const void* dict, size_t dictSize,
1030 const ZSTD_DDict* ddict)
1031{
1032 void* const dststart = dst;
1033 int moreThan1Frame = 0;
1034
1035 DEBUGLOG(5, "ZSTD_decompressMultiFrame");
1036 assert(dict==NULL || ddict==NULL); /* either dict or ddict set, not both */
1037
1038 if (ddict) {
1039 dict = ZSTD_DDict_dictContent(ddict);
1040 dictSize = ZSTD_DDict_dictSize(ddict);
1041 }
1042
1043 while (srcSize >= ZSTD_startingInputLength(format: dctx->format)) {
1044
1045
1046 if (dctx->format == ZSTD_f_zstd1 && srcSize >= 4) {
1047 U32 const magicNumber = MEM_readLE32(memPtr: src);
1048 DEBUGLOG(5, "reading magic number %08X", (unsigned)magicNumber);
1049 if ((magicNumber & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) {
1050 /* skippable frame detected : skip it */
1051 size_t const skippableSize = readSkippableFrameSize(src, srcSize);
1052 FORWARD_IF_ERROR(skippableSize, "invalid skippable frame");
1053 assert(skippableSize <= srcSize);
1054
1055 src = (const BYTE *)src + skippableSize;
1056 srcSize -= skippableSize;
1057 continue; /* check next frame */
1058 } }
1059
1060 if (ddict) {
1061 /* we were called from ZSTD_decompress_usingDDict */
1062 FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(dctx, ddict), "");
1063 } else {
1064 /* this will initialize correctly with no dict if dict == NULL, so
1065 * use this in all cases but ddict */
1066 FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDict(dctx, dict, dictSize), "");
1067 }
1068 ZSTD_checkContinuity(dctx, dst, dstSize: dstCapacity);
1069
1070 { const size_t res = ZSTD_decompressFrame(dctx, dst, dstCapacity,
1071 srcPtr: &src, srcSizePtr: &srcSize);
1072 RETURN_ERROR_IF(
1073 (ZSTD_getErrorCode(res) == ZSTD_error_prefix_unknown)
1074 && (moreThan1Frame==1),
1075 srcSize_wrong,
1076 "At least one frame successfully completed, "
1077 "but following bytes are garbage: "
1078 "it's more likely to be a srcSize error, "
1079 "specifying more input bytes than size of frame(s). "
1080 "Note: one could be unlucky, it might be a corruption error instead, "
1081 "happening right at the place where we expect zstd magic bytes. "
1082 "But this is _much_ less likely than a srcSize field error.");
1083 if (ZSTD_isError(code: res)) return res;
1084 assert(res <= dstCapacity);
1085 if (res != 0)
1086 dst = (BYTE*)dst + res;
1087 dstCapacity -= res;
1088 }
1089 moreThan1Frame = 1;
1090 } /* while (srcSize >= ZSTD_frameHeaderSize_prefix) */
1091
1092 RETURN_ERROR_IF(srcSize, srcSize_wrong, "input not entirely consumed");
1093
1094 return (size_t)((BYTE*)dst - (BYTE*)dststart);
1095}
1096
1097size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
1098 void* dst, size_t dstCapacity,
1099 const void* src, size_t srcSize,
1100 const void* dict, size_t dictSize)
1101{
1102 return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, dict, dictSize, NULL);
1103}
1104
1105
1106static ZSTD_DDict const* ZSTD_getDDict(ZSTD_DCtx* dctx)
1107{
1108 switch (dctx->dictUses) {
1109 default:
1110 assert(0 /* Impossible */);
1111 ZSTD_FALLTHROUGH;
1112 case ZSTD_dont_use:
1113 ZSTD_clearDict(dctx);
1114 return NULL;
1115 case ZSTD_use_indefinitely:
1116 return dctx->ddict;
1117 case ZSTD_use_once:
1118 dctx->dictUses = ZSTD_dont_use;
1119 return dctx->ddict;
1120 }
1121}
1122
1123size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
1124{
1125 return ZSTD_decompress_usingDDict(dctx, dst, dstCapacity, src, srcSize, ddict: ZSTD_getDDict(dctx));
1126}
1127
1128
1129size_t ZSTD_decompress(void* dst, size_t dstCapacity, const void* src, size_t srcSize)
1130{
1131#if defined(ZSTD_HEAPMODE) && (ZSTD_HEAPMODE>=1)
1132 size_t regenSize;
1133 ZSTD_DCtx* const dctx = ZSTD_createDCtx_internal(customMem: ZSTD_defaultCMem);
1134 RETURN_ERROR_IF(dctx==NULL, memory_allocation, "NULL pointer!");
1135 regenSize = ZSTD_decompressDCtx(dctx, dst, dstCapacity, src, srcSize);
1136 ZSTD_freeDCtx(dctx);
1137 return regenSize;
1138#else /* stack mode */
1139 ZSTD_DCtx dctx;
1140 ZSTD_initDCtx_internal(&dctx);
1141 return ZSTD_decompressDCtx(&dctx, dst, dstCapacity, src, srcSize);
1142#endif
1143}
1144
1145
1146/*-**************************************
1147* Advanced Streaming Decompression API
1148* Bufferless and synchronous
1149****************************************/
1150size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx) { return dctx->expected; }
1151
1152/*
1153 * Similar to ZSTD_nextSrcSizeToDecompress(), but when a block input can be streamed, we
1154 * allow taking a partial block as the input. Currently only raw uncompressed blocks can
1155 * be streamed.
1156 *
1157 * For blocks that can be streamed, this allows us to reduce the latency until we produce
1158 * output, and avoid copying the input.
1159 *
1160 * @param inputSize - The total amount of input that the caller currently has.
1161 */
1162static size_t ZSTD_nextSrcSizeToDecompressWithInputSize(ZSTD_DCtx* dctx, size_t inputSize) {
1163 if (!(dctx->stage == ZSTDds_decompressBlock || dctx->stage == ZSTDds_decompressLastBlock))
1164 return dctx->expected;
1165 if (dctx->bType != bt_raw)
1166 return dctx->expected;
1167 return BOUNDED(1, inputSize, dctx->expected);
1168}
1169
1170ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx) {
1171 switch(dctx->stage)
1172 {
1173 default: /* should not happen */
1174 assert(0);
1175 ZSTD_FALLTHROUGH;
1176 case ZSTDds_getFrameHeaderSize:
1177 ZSTD_FALLTHROUGH;
1178 case ZSTDds_decodeFrameHeader:
1179 return ZSTDnit_frameHeader;
1180 case ZSTDds_decodeBlockHeader:
1181 return ZSTDnit_blockHeader;
1182 case ZSTDds_decompressBlock:
1183 return ZSTDnit_block;
1184 case ZSTDds_decompressLastBlock:
1185 return ZSTDnit_lastBlock;
1186 case ZSTDds_checkChecksum:
1187 return ZSTDnit_checksum;
1188 case ZSTDds_decodeSkippableHeader:
1189 ZSTD_FALLTHROUGH;
1190 case ZSTDds_skipFrame:
1191 return ZSTDnit_skippableFrame;
1192 }
1193}
1194
1195static int ZSTD_isSkipFrame(ZSTD_DCtx* dctx) { return dctx->stage == ZSTDds_skipFrame; }
1196
1197/* ZSTD_decompressContinue() :
1198 * srcSize : must be the exact nb of bytes expected (see ZSTD_nextSrcSizeToDecompress())
1199 * @return : nb of bytes generated into `dst` (necessarily <= `dstCapacity)
1200 * or an error code, which can be tested using ZSTD_isError() */
1201size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
1202{
1203 DEBUGLOG(5, "ZSTD_decompressContinue (srcSize:%u)", (unsigned)srcSize);
1204 /* Sanity check */
1205 RETURN_ERROR_IF(srcSize != ZSTD_nextSrcSizeToDecompressWithInputSize(dctx, srcSize), srcSize_wrong, "not allowed");
1206 ZSTD_checkContinuity(dctx, dst, dstSize: dstCapacity);
1207
1208 dctx->processedCSize += srcSize;
1209
1210 switch (dctx->stage)
1211 {
1212 case ZSTDds_getFrameHeaderSize :
1213 assert(src != NULL);
1214 if (dctx->format == ZSTD_f_zstd1) { /* allows header */
1215 assert(srcSize >= ZSTD_FRAMEIDSIZE); /* to read skippable magic number */
1216 if ((MEM_readLE32(memPtr: src) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */
1217 ZSTD_memcpy(dctx->headerBuffer, src, srcSize);
1218 dctx->expected = ZSTD_SKIPPABLEHEADERSIZE - srcSize; /* remaining to load to get full skippable frame header */
1219 dctx->stage = ZSTDds_decodeSkippableHeader;
1220 return 0;
1221 } }
1222 dctx->headerSize = ZSTD_frameHeaderSize_internal(src, srcSize, format: dctx->format);
1223 if (ZSTD_isError(code: dctx->headerSize)) return dctx->headerSize;
1224 ZSTD_memcpy(dctx->headerBuffer, src, srcSize);
1225 dctx->expected = dctx->headerSize - srcSize;
1226 dctx->stage = ZSTDds_decodeFrameHeader;
1227 return 0;
1228
1229 case ZSTDds_decodeFrameHeader:
1230 assert(src != NULL);
1231 ZSTD_memcpy(dctx->headerBuffer + (dctx->headerSize - srcSize), src, srcSize);
1232 FORWARD_IF_ERROR(ZSTD_decodeFrameHeader(dctx, dctx->headerBuffer, dctx->headerSize), "");
1233 dctx->expected = ZSTD_blockHeaderSize;
1234 dctx->stage = ZSTDds_decodeBlockHeader;
1235 return 0;
1236
1237 case ZSTDds_decodeBlockHeader:
1238 { blockProperties_t bp;
1239 size_t const cBlockSize = ZSTD_getcBlockSize(src, srcSize: ZSTD_blockHeaderSize, bpPtr: &bp);
1240 if (ZSTD_isError(code: cBlockSize)) return cBlockSize;
1241 RETURN_ERROR_IF(cBlockSize > dctx->fParams.blockSizeMax, corruption_detected, "Block Size Exceeds Maximum");
1242 dctx->expected = cBlockSize;
1243 dctx->bType = bp.blockType;
1244 dctx->rleSize = bp.origSize;
1245 if (cBlockSize) {
1246 dctx->stage = bp.lastBlock ? ZSTDds_decompressLastBlock : ZSTDds_decompressBlock;
1247 return 0;
1248 }
1249 /* empty block */
1250 if (bp.lastBlock) {
1251 if (dctx->fParams.checksumFlag) {
1252 dctx->expected = 4;
1253 dctx->stage = ZSTDds_checkChecksum;
1254 } else {
1255 dctx->expected = 0; /* end of frame */
1256 dctx->stage = ZSTDds_getFrameHeaderSize;
1257 }
1258 } else {
1259 dctx->expected = ZSTD_blockHeaderSize; /* jump to next header */
1260 dctx->stage = ZSTDds_decodeBlockHeader;
1261 }
1262 return 0;
1263 }
1264
1265 case ZSTDds_decompressLastBlock:
1266 case ZSTDds_decompressBlock:
1267 DEBUGLOG(5, "ZSTD_decompressContinue: case ZSTDds_decompressBlock");
1268 { size_t rSize;
1269 switch(dctx->bType)
1270 {
1271 case bt_compressed:
1272 DEBUGLOG(5, "ZSTD_decompressContinue: case bt_compressed");
1273 assert(dctx->isFrameDecompression == 1);
1274 rSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, streaming: is_streaming);
1275 dctx->expected = 0; /* Streaming not supported */
1276 break;
1277 case bt_raw :
1278 assert(srcSize <= dctx->expected);
1279 rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, srcSize);
1280 FORWARD_IF_ERROR(rSize, "ZSTD_copyRawBlock failed");
1281 assert(rSize == srcSize);
1282 dctx->expected -= rSize;
1283 break;
1284 case bt_rle :
1285 rSize = ZSTD_setRleBlock(dst, dstCapacity, b: *(const BYTE*)src, regenSize: dctx->rleSize);
1286 dctx->expected = 0; /* Streaming not supported */
1287 break;
1288 case bt_reserved : /* should never happen */
1289 default:
1290 RETURN_ERROR(corruption_detected, "invalid block type");
1291 }
1292 FORWARD_IF_ERROR(rSize, "");
1293 RETURN_ERROR_IF(rSize > dctx->fParams.blockSizeMax, corruption_detected, "Decompressed Block Size Exceeds Maximum");
1294 DEBUGLOG(5, "ZSTD_decompressContinue: decoded size from block : %u", (unsigned)rSize);
1295 dctx->decodedSize += rSize;
1296 if (dctx->validateChecksum) xxh64_update(state: &dctx->xxhState, input: dst, length: rSize);
1297 dctx->previousDstEnd = (char*)dst + rSize;
1298
1299 /* Stay on the same stage until we are finished streaming the block. */
1300 if (dctx->expected > 0) {
1301 return rSize;
1302 }
1303
1304 if (dctx->stage == ZSTDds_decompressLastBlock) { /* end of frame */
1305 DEBUGLOG(4, "ZSTD_decompressContinue: decoded size from frame : %u", (unsigned)dctx->decodedSize);
1306 RETURN_ERROR_IF(
1307 dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN
1308 && dctx->decodedSize != dctx->fParams.frameContentSize,
1309 corruption_detected, "");
1310 if (dctx->fParams.checksumFlag) { /* another round for frame checksum */
1311 dctx->expected = 4;
1312 dctx->stage = ZSTDds_checkChecksum;
1313 } else {
1314 ZSTD_DCtx_trace_end(dctx, uncompressedSize: dctx->decodedSize, compressedSize: dctx->processedCSize, /* streaming */ 1);
1315 dctx->expected = 0; /* ends here */
1316 dctx->stage = ZSTDds_getFrameHeaderSize;
1317 }
1318 } else {
1319 dctx->stage = ZSTDds_decodeBlockHeader;
1320 dctx->expected = ZSTD_blockHeaderSize;
1321 }
1322 return rSize;
1323 }
1324
1325 case ZSTDds_checkChecksum:
1326 assert(srcSize == 4); /* guaranteed by dctx->expected */
1327 {
1328 if (dctx->validateChecksum) {
1329 U32 const h32 = (U32)xxh64_digest(state: &dctx->xxhState);
1330 U32 const check32 = MEM_readLE32(memPtr: src);
1331 DEBUGLOG(4, "ZSTD_decompressContinue: checksum : calculated %08X :: %08X read", (unsigned)h32, (unsigned)check32);
1332 RETURN_ERROR_IF(check32 != h32, checksum_wrong, "");
1333 }
1334 ZSTD_DCtx_trace_end(dctx, uncompressedSize: dctx->decodedSize, compressedSize: dctx->processedCSize, /* streaming */ 1);
1335 dctx->expected = 0;
1336 dctx->stage = ZSTDds_getFrameHeaderSize;
1337 return 0;
1338 }
1339
1340 case ZSTDds_decodeSkippableHeader:
1341 assert(src != NULL);
1342 assert(srcSize <= ZSTD_SKIPPABLEHEADERSIZE);
1343 assert(dctx->format != ZSTD_f_zstd1_magicless);
1344 ZSTD_memcpy(dctx->headerBuffer + (ZSTD_SKIPPABLEHEADERSIZE - srcSize), src, srcSize); /* complete skippable header */
1345 dctx->expected = MEM_readLE32(memPtr: dctx->headerBuffer + ZSTD_FRAMEIDSIZE); /* note : dctx->expected can grow seriously large, beyond local buffer size */
1346 dctx->stage = ZSTDds_skipFrame;
1347 return 0;
1348
1349 case ZSTDds_skipFrame:
1350 dctx->expected = 0;
1351 dctx->stage = ZSTDds_getFrameHeaderSize;
1352 return 0;
1353
1354 default:
1355 assert(0); /* impossible */
1356 RETURN_ERROR(GENERIC, "impossible to reach"); /* some compilers require default to do something */
1357 }
1358}
1359
1360
1361static size_t ZSTD_refDictContent(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
1362{
1363 dctx->dictEnd = dctx->previousDstEnd;
1364 dctx->virtualStart = (const char*)dict - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->prefixStart));
1365 dctx->prefixStart = dict;
1366 dctx->previousDstEnd = (const char*)dict + dictSize;
1367#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
1368 dctx->dictContentBeginForFuzzing = dctx->prefixStart;
1369 dctx->dictContentEndForFuzzing = dctx->previousDstEnd;
1370#endif
1371 return 0;
1372}
1373
1374/*! ZSTD_loadDEntropy() :
1375 * dict : must point at beginning of a valid zstd dictionary.
1376 * @return : size of entropy tables read */
1377size_t
1378ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
1379 const void* const dict, size_t const dictSize)
1380{
1381 const BYTE* dictPtr = (const BYTE*)dict;
1382 const BYTE* const dictEnd = dictPtr + dictSize;
1383
1384 RETURN_ERROR_IF(dictSize <= 8, dictionary_corrupted, "dict is too small");
1385 assert(MEM_readLE32(dict) == ZSTD_MAGIC_DICTIONARY); /* dict must be valid */
1386 dictPtr += 8; /* skip header = magic + dictID */
1387
1388 ZSTD_STATIC_ASSERT(offsetof(ZSTD_entropyDTables_t, OFTable) == offsetof(ZSTD_entropyDTables_t, LLTable) + sizeof(entropy->LLTable));
1389 ZSTD_STATIC_ASSERT(offsetof(ZSTD_entropyDTables_t, MLTable) == offsetof(ZSTD_entropyDTables_t, OFTable) + sizeof(entropy->OFTable));
1390 ZSTD_STATIC_ASSERT(sizeof(entropy->LLTable) + sizeof(entropy->OFTable) + sizeof(entropy->MLTable) >= HUF_DECOMPRESS_WORKSPACE_SIZE);
1391 { void* const workspace = &entropy->LLTable; /* use fse tables as temporary workspace; implies fse tables are grouped together */
1392 size_t const workspaceSize = sizeof(entropy->LLTable) + sizeof(entropy->OFTable) + sizeof(entropy->MLTable);
1393#ifdef HUF_FORCE_DECOMPRESS_X1
1394 /* in minimal huffman, we always use X1 variants */
1395 size_t const hSize = HUF_readDTableX1_wksp(entropy->hufTable,
1396 dictPtr, dictEnd - dictPtr,
1397 workspace, workspaceSize, /* flags */ 0);
1398#else
1399 size_t const hSize = HUF_readDTableX2_wksp(DTable: entropy->hufTable,
1400 src: dictPtr, srcSize: (size_t)(dictEnd - dictPtr),
1401 workSpace: workspace, wkspSize: workspaceSize, /* flags */ 0);
1402#endif
1403 RETURN_ERROR_IF(HUF_isError(hSize), dictionary_corrupted, "");
1404 dictPtr += hSize;
1405 }
1406
1407 { short offcodeNCount[MaxOff+1];
1408 unsigned offcodeMaxValue = MaxOff, offcodeLog;
1409 size_t const offcodeHeaderSize = FSE_readNCount(normalizedCounter: offcodeNCount, maxSymbolValuePtr: &offcodeMaxValue, tableLogPtr: &offcodeLog, rBuffer: dictPtr, rBuffSize: (size_t)(dictEnd-dictPtr));
1410 RETURN_ERROR_IF(FSE_isError(offcodeHeaderSize), dictionary_corrupted, "");
1411 RETURN_ERROR_IF(offcodeMaxValue > MaxOff, dictionary_corrupted, "");
1412 RETURN_ERROR_IF(offcodeLog > OffFSELog, dictionary_corrupted, "");
1413 ZSTD_buildFSETable( dt: entropy->OFTable,
1414 normalizedCounter: offcodeNCount, maxSymbolValue: offcodeMaxValue,
1415 baseValue: OF_base, nbAdditionalBits: OF_bits,
1416 tableLog: offcodeLog,
1417 wksp: entropy->workspace, wkspSize: sizeof(entropy->workspace),
1418 /* bmi2 */0);
1419 dictPtr += offcodeHeaderSize;
1420 }
1421
1422 { short matchlengthNCount[MaxML+1];
1423 unsigned matchlengthMaxValue = MaxML, matchlengthLog;
1424 size_t const matchlengthHeaderSize = FSE_readNCount(normalizedCounter: matchlengthNCount, maxSymbolValuePtr: &matchlengthMaxValue, tableLogPtr: &matchlengthLog, rBuffer: dictPtr, rBuffSize: (size_t)(dictEnd-dictPtr));
1425 RETURN_ERROR_IF(FSE_isError(matchlengthHeaderSize), dictionary_corrupted, "");
1426 RETURN_ERROR_IF(matchlengthMaxValue > MaxML, dictionary_corrupted, "");
1427 RETURN_ERROR_IF(matchlengthLog > MLFSELog, dictionary_corrupted, "");
1428 ZSTD_buildFSETable( dt: entropy->MLTable,
1429 normalizedCounter: matchlengthNCount, maxSymbolValue: matchlengthMaxValue,
1430 baseValue: ML_base, nbAdditionalBits: ML_bits,
1431 tableLog: matchlengthLog,
1432 wksp: entropy->workspace, wkspSize: sizeof(entropy->workspace),
1433 /* bmi2 */ 0);
1434 dictPtr += matchlengthHeaderSize;
1435 }
1436
1437 { short litlengthNCount[MaxLL+1];
1438 unsigned litlengthMaxValue = MaxLL, litlengthLog;
1439 size_t const litlengthHeaderSize = FSE_readNCount(normalizedCounter: litlengthNCount, maxSymbolValuePtr: &litlengthMaxValue, tableLogPtr: &litlengthLog, rBuffer: dictPtr, rBuffSize: (size_t)(dictEnd-dictPtr));
1440 RETURN_ERROR_IF(FSE_isError(litlengthHeaderSize), dictionary_corrupted, "");
1441 RETURN_ERROR_IF(litlengthMaxValue > MaxLL, dictionary_corrupted, "");
1442 RETURN_ERROR_IF(litlengthLog > LLFSELog, dictionary_corrupted, "");
1443 ZSTD_buildFSETable( dt: entropy->LLTable,
1444 normalizedCounter: litlengthNCount, maxSymbolValue: litlengthMaxValue,
1445 baseValue: LL_base, nbAdditionalBits: LL_bits,
1446 tableLog: litlengthLog,
1447 wksp: entropy->workspace, wkspSize: sizeof(entropy->workspace),
1448 /* bmi2 */ 0);
1449 dictPtr += litlengthHeaderSize;
1450 }
1451
1452 RETURN_ERROR_IF(dictPtr+12 > dictEnd, dictionary_corrupted, "");
1453 { int i;
1454 size_t const dictContentSize = (size_t)(dictEnd - (dictPtr+12));
1455 for (i=0; i<3; i++) {
1456 U32 const rep = MEM_readLE32(memPtr: dictPtr); dictPtr += 4;
1457 RETURN_ERROR_IF(rep==0 || rep > dictContentSize,
1458 dictionary_corrupted, "");
1459 entropy->rep[i] = rep;
1460 } }
1461
1462 return (size_t)(dictPtr - (const BYTE*)dict);
1463}
1464
1465static size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
1466{
1467 if (dictSize < 8) return ZSTD_refDictContent(dctx, dict, dictSize);
1468 { U32 const magic = MEM_readLE32(memPtr: dict);
1469 if (magic != ZSTD_MAGIC_DICTIONARY) {
1470 return ZSTD_refDictContent(dctx, dict, dictSize); /* pure content mode */
1471 } }
1472 dctx->dictID = MEM_readLE32(memPtr: (const char*)dict + ZSTD_FRAMEIDSIZE);
1473
1474 /* load entropy tables */
1475 { size_t const eSize = ZSTD_loadDEntropy(entropy: &dctx->entropy, dict, dictSize);
1476 RETURN_ERROR_IF(ZSTD_isError(eSize), dictionary_corrupted, "");
1477 dict = (const char*)dict + eSize;
1478 dictSize -= eSize;
1479 }
1480 dctx->litEntropy = dctx->fseEntropy = 1;
1481
1482 /* reference dictionary content */
1483 return ZSTD_refDictContent(dctx, dict, dictSize);
1484}
1485
1486size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx)
1487{
1488 assert(dctx != NULL);
1489 dctx->expected = ZSTD_startingInputLength(format: dctx->format); /* dctx->format must be properly set */
1490 dctx->stage = ZSTDds_getFrameHeaderSize;
1491 dctx->processedCSize = 0;
1492 dctx->decodedSize = 0;
1493 dctx->previousDstEnd = NULL;
1494 dctx->prefixStart = NULL;
1495 dctx->virtualStart = NULL;
1496 dctx->dictEnd = NULL;
1497 dctx->entropy.hufTable[0] = (HUF_DTable)((ZSTD_HUFFDTABLE_CAPACITY_LOG)*0x1000001); /* cover both little and big endian */
1498 dctx->litEntropy = dctx->fseEntropy = 0;
1499 dctx->dictID = 0;
1500 dctx->bType = bt_reserved;
1501 dctx->isFrameDecompression = 1;
1502 ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.rep) == sizeof(repStartValue));
1503 ZSTD_memcpy(dctx->entropy.rep, repStartValue, sizeof(repStartValue)); /* initial repcodes */
1504 dctx->LLTptr = dctx->entropy.LLTable;
1505 dctx->MLTptr = dctx->entropy.MLTable;
1506 dctx->OFTptr = dctx->entropy.OFTable;
1507 dctx->HUFptr = dctx->entropy.hufTable;
1508 return 0;
1509}
1510
1511size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
1512{
1513 FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) , "");
1514 if (dict && dictSize)
1515 RETURN_ERROR_IF(
1516 ZSTD_isError(ZSTD_decompress_insertDictionary(dctx, dict, dictSize)),
1517 dictionary_corrupted, "");
1518 return 0;
1519}
1520
1521
1522/* ====== ZSTD_DDict ====== */
1523
1524size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
1525{
1526 DEBUGLOG(4, "ZSTD_decompressBegin_usingDDict");
1527 assert(dctx != NULL);
1528 if (ddict) {
1529 const char* const dictStart = (const char*)ZSTD_DDict_dictContent(ddict);
1530 size_t const dictSize = ZSTD_DDict_dictSize(ddict);
1531 const void* const dictEnd = dictStart + dictSize;
1532 dctx->ddictIsCold = (dctx->dictEnd != dictEnd);
1533 DEBUGLOG(4, "DDict is %s",
1534 dctx->ddictIsCold ? "~cold~" : "hot!");
1535 }
1536 FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) , "");
1537 if (ddict) { /* NULL ddict is equivalent to no dictionary */
1538 ZSTD_copyDDictParameters(dctx, ddict);
1539 }
1540 return 0;
1541}
1542
1543/*! ZSTD_getDictID_fromDict() :
1544 * Provides the dictID stored within dictionary.
1545 * if @return == 0, the dictionary is not conformant with Zstandard specification.
1546 * It can still be loaded, but as a content-only dictionary. */
1547unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize)
1548{
1549 if (dictSize < 8) return 0;
1550 if (MEM_readLE32(memPtr: dict) != ZSTD_MAGIC_DICTIONARY) return 0;
1551 return MEM_readLE32(memPtr: (const char*)dict + ZSTD_FRAMEIDSIZE);
1552}
1553
1554/*! ZSTD_getDictID_fromFrame() :
1555 * Provides the dictID required to decompress frame stored within `src`.
1556 * If @return == 0, the dictID could not be decoded.
1557 * This could for one of the following reasons :
1558 * - The frame does not require a dictionary (most common case).
1559 * - The frame was built with dictID intentionally removed.
1560 * Needed dictionary is a hidden piece of information.
1561 * Note : this use case also happens when using a non-conformant dictionary.
1562 * - `srcSize` is too small, and as a result, frame header could not be decoded.
1563 * Note : possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`.
1564 * - This is not a Zstandard frame.
1565 * When identifying the exact failure cause, it's possible to use
1566 * ZSTD_getFrameHeader(), which will provide a more precise error code. */
1567unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize)
1568{
1569 ZSTD_FrameHeader zfp = { 0, 0, 0, ZSTD_frame, 0, 0, 0, 0, 0 };
1570 size_t const hError = ZSTD_getFrameHeader(zfhPtr: &zfp, src, srcSize);
1571 if (ZSTD_isError(code: hError)) return 0;
1572 return zfp.dictID;
1573}
1574
1575
1576/*! ZSTD_decompress_usingDDict() :
1577* Decompression using a pre-digested Dictionary
1578* Use dictionary without significant overhead. */
1579size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
1580 void* dst, size_t dstCapacity,
1581 const void* src, size_t srcSize,
1582 const ZSTD_DDict* ddict)
1583{
1584 /* pass content and size in case legacy frames are encountered */
1585 return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize,
1586 NULL, dictSize: 0,
1587 ddict);
1588}
1589
1590
1591/*=====================================
1592* Streaming decompression
1593*====================================*/
1594
1595ZSTD_DStream* ZSTD_createDStream(void)
1596{
1597 DEBUGLOG(3, "ZSTD_createDStream");
1598 return ZSTD_createDCtx_internal(customMem: ZSTD_defaultCMem);
1599}
1600
1601ZSTD_DStream* ZSTD_initStaticDStream(void *workspace, size_t workspaceSize)
1602{
1603 return ZSTD_initStaticDCtx(workspace, workspaceSize);
1604}
1605
1606ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem)
1607{
1608 return ZSTD_createDCtx_internal(customMem);
1609}
1610
1611size_t ZSTD_freeDStream(ZSTD_DStream* zds)
1612{
1613 return ZSTD_freeDCtx(dctx: zds);
1614}
1615
1616
1617/* *** Initialization *** */
1618
1619size_t ZSTD_DStreamInSize(void) { return ZSTD_BLOCKSIZE_MAX + ZSTD_blockHeaderSize; }
1620size_t ZSTD_DStreamOutSize(void) { return ZSTD_BLOCKSIZE_MAX; }
1621
1622size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx,
1623 const void* dict, size_t dictSize,
1624 ZSTD_dictLoadMethod_e dictLoadMethod,
1625 ZSTD_dictContentType_e dictContentType)
1626{
1627 RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
1628 ZSTD_clearDict(dctx);
1629 if (dict && dictSize != 0) {
1630 dctx->ddictLocal = ZSTD_createDDict_advanced(dict, dictSize, dictLoadMethod, dictContentType, customMem: dctx->customMem);
1631 RETURN_ERROR_IF(dctx->ddictLocal == NULL, memory_allocation, "NULL pointer!");
1632 dctx->ddict = dctx->ddictLocal;
1633 dctx->dictUses = ZSTD_use_indefinitely;
1634 }
1635 return 0;
1636}
1637
1638size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
1639{
1640 return ZSTD_DCtx_loadDictionary_advanced(dctx, dict, dictSize, dictLoadMethod: ZSTD_dlm_byRef, dictContentType: ZSTD_dct_auto);
1641}
1642
1643size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
1644{
1645 return ZSTD_DCtx_loadDictionary_advanced(dctx, dict, dictSize, dictLoadMethod: ZSTD_dlm_byCopy, dictContentType: ZSTD_dct_auto);
1646}
1647
1648size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType)
1649{
1650 FORWARD_IF_ERROR(ZSTD_DCtx_loadDictionary_advanced(dctx, prefix, prefixSize, ZSTD_dlm_byRef, dictContentType), "");
1651 dctx->dictUses = ZSTD_use_once;
1652 return 0;
1653}
1654
1655size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize)
1656{
1657 return ZSTD_DCtx_refPrefix_advanced(dctx, prefix, prefixSize, dictContentType: ZSTD_dct_rawContent);
1658}
1659
1660
1661/* ZSTD_initDStream_usingDict() :
1662 * return : expected size, aka ZSTD_startingInputLength().
1663 * this function cannot fail */
1664size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize)
1665{
1666 DEBUGLOG(4, "ZSTD_initDStream_usingDict");
1667 FORWARD_IF_ERROR( ZSTD_DCtx_reset(zds, ZSTD_reset_session_only) , "");
1668 FORWARD_IF_ERROR( ZSTD_DCtx_loadDictionary(zds, dict, dictSize) , "");
1669 return ZSTD_startingInputLength(format: zds->format);
1670}
1671
1672/* note : this variant can't fail */
1673size_t ZSTD_initDStream(ZSTD_DStream* zds)
1674{
1675 DEBUGLOG(4, "ZSTD_initDStream");
1676 FORWARD_IF_ERROR(ZSTD_DCtx_reset(zds, ZSTD_reset_session_only), "");
1677 FORWARD_IF_ERROR(ZSTD_DCtx_refDDict(zds, NULL), "");
1678 return ZSTD_startingInputLength(format: zds->format);
1679}
1680
1681/* ZSTD_initDStream_usingDDict() :
1682 * ddict will just be referenced, and must outlive decompression session
1683 * this function cannot fail */
1684size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* dctx, const ZSTD_DDict* ddict)
1685{
1686 DEBUGLOG(4, "ZSTD_initDStream_usingDDict");
1687 FORWARD_IF_ERROR( ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only) , "");
1688 FORWARD_IF_ERROR( ZSTD_DCtx_refDDict(dctx, ddict) , "");
1689 return ZSTD_startingInputLength(format: dctx->format);
1690}
1691
1692/* ZSTD_resetDStream() :
1693 * return : expected size, aka ZSTD_startingInputLength().
1694 * this function cannot fail */
1695size_t ZSTD_resetDStream(ZSTD_DStream* dctx)
1696{
1697 DEBUGLOG(4, "ZSTD_resetDStream");
1698 FORWARD_IF_ERROR(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only), "");
1699 return ZSTD_startingInputLength(format: dctx->format);
1700}
1701
1702
1703size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict)
1704{
1705 RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
1706 ZSTD_clearDict(dctx);
1707 if (ddict) {
1708 dctx->ddict = ddict;
1709 dctx->dictUses = ZSTD_use_indefinitely;
1710 if (dctx->refMultipleDDicts == ZSTD_rmd_refMultipleDDicts) {
1711 if (dctx->ddictSet == NULL) {
1712 dctx->ddictSet = ZSTD_createDDictHashSet(customMem: dctx->customMem);
1713 if (!dctx->ddictSet) {
1714 RETURN_ERROR(memory_allocation, "Failed to allocate memory for hash set!");
1715 }
1716 }
1717 assert(!dctx->staticSize); /* Impossible: ddictSet cannot have been allocated if static dctx */
1718 FORWARD_IF_ERROR(ZSTD_DDictHashSet_addDDict(dctx->ddictSet, ddict, dctx->customMem), "");
1719 }
1720 }
1721 return 0;
1722}
1723
1724/* ZSTD_DCtx_setMaxWindowSize() :
1725 * note : no direct equivalence in ZSTD_DCtx_setParameter,
1726 * since this version sets windowSize, and the other sets windowLog */
1727size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize)
1728{
1729 ZSTD_bounds const bounds = ZSTD_dParam_getBounds(dParam: ZSTD_d_windowLogMax);
1730 size_t const min = (size_t)1 << bounds.lowerBound;
1731 size_t const max = (size_t)1 << bounds.upperBound;
1732 RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
1733 RETURN_ERROR_IF(maxWindowSize < min, parameter_outOfBound, "");
1734 RETURN_ERROR_IF(maxWindowSize > max, parameter_outOfBound, "");
1735 dctx->maxWindowSize = maxWindowSize;
1736 return 0;
1737}
1738
1739size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format)
1740{
1741 return ZSTD_DCtx_setParameter(dctx, ZSTD_d_format, value: (int)format);
1742}
1743
1744ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam)
1745{
1746 ZSTD_bounds bounds = { 0, 0, 0 };
1747 switch(dParam) {
1748 case ZSTD_d_windowLogMax:
1749 bounds.lowerBound = ZSTD_WINDOWLOG_ABSOLUTEMIN;
1750 bounds.upperBound = ZSTD_WINDOWLOG_MAX;
1751 return bounds;
1752 case ZSTD_d_format:
1753 bounds.lowerBound = (int)ZSTD_f_zstd1;
1754 bounds.upperBound = (int)ZSTD_f_zstd1_magicless;
1755 ZSTD_STATIC_ASSERT(ZSTD_f_zstd1 < ZSTD_f_zstd1_magicless);
1756 return bounds;
1757 case ZSTD_d_stableOutBuffer:
1758 bounds.lowerBound = (int)ZSTD_bm_buffered;
1759 bounds.upperBound = (int)ZSTD_bm_stable;
1760 return bounds;
1761 case ZSTD_d_forceIgnoreChecksum:
1762 bounds.lowerBound = (int)ZSTD_d_validateChecksum;
1763 bounds.upperBound = (int)ZSTD_d_ignoreChecksum;
1764 return bounds;
1765 case ZSTD_d_refMultipleDDicts:
1766 bounds.lowerBound = (int)ZSTD_rmd_refSingleDDict;
1767 bounds.upperBound = (int)ZSTD_rmd_refMultipleDDicts;
1768 return bounds;
1769 case ZSTD_d_disableHuffmanAssembly:
1770 bounds.lowerBound = 0;
1771 bounds.upperBound = 1;
1772 return bounds;
1773 case ZSTD_d_maxBlockSize:
1774 bounds.lowerBound = ZSTD_BLOCKSIZE_MAX_MIN;
1775 bounds.upperBound = ZSTD_BLOCKSIZE_MAX;
1776 return bounds;
1777
1778 default:;
1779 }
1780 bounds.error = ERROR(parameter_unsupported);
1781 return bounds;
1782}
1783
1784/* ZSTD_dParam_withinBounds:
1785 * @return 1 if value is within dParam bounds,
1786 * 0 otherwise */
1787static int ZSTD_dParam_withinBounds(ZSTD_dParameter dParam, int value)
1788{
1789 ZSTD_bounds const bounds = ZSTD_dParam_getBounds(dParam);
1790 if (ZSTD_isError(code: bounds.error)) return 0;
1791 if (value < bounds.lowerBound) return 0;
1792 if (value > bounds.upperBound) return 0;
1793 return 1;
1794}
1795
1796#define CHECK_DBOUNDS(p,v) { \
1797 RETURN_ERROR_IF(!ZSTD_dParam_withinBounds(p, v), parameter_outOfBound, ""); \
1798}
1799
1800size_t ZSTD_DCtx_getParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int* value)
1801{
1802 switch (param) {
1803 case ZSTD_d_windowLogMax:
1804 *value = (int)ZSTD_highbit32(val: (U32)dctx->maxWindowSize);
1805 return 0;
1806 case ZSTD_d_format:
1807 *value = (int)dctx->format;
1808 return 0;
1809 case ZSTD_d_stableOutBuffer:
1810 *value = (int)dctx->outBufferMode;
1811 return 0;
1812 case ZSTD_d_forceIgnoreChecksum:
1813 *value = (int)dctx->forceIgnoreChecksum;
1814 return 0;
1815 case ZSTD_d_refMultipleDDicts:
1816 *value = (int)dctx->refMultipleDDicts;
1817 return 0;
1818 case ZSTD_d_disableHuffmanAssembly:
1819 *value = (int)dctx->disableHufAsm;
1820 return 0;
1821 case ZSTD_d_maxBlockSize:
1822 *value = dctx->maxBlockSizeParam;
1823 return 0;
1824 default:;
1825 }
1826 RETURN_ERROR(parameter_unsupported, "");
1827}
1828
1829size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter dParam, int value)
1830{
1831 RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
1832 switch(dParam) {
1833 case ZSTD_d_windowLogMax:
1834 if (value == 0) value = ZSTD_WINDOWLOG_LIMIT_DEFAULT;
1835 CHECK_DBOUNDS(ZSTD_d_windowLogMax, value);
1836 dctx->maxWindowSize = ((size_t)1) << value;
1837 return 0;
1838 case ZSTD_d_format:
1839 CHECK_DBOUNDS(ZSTD_d_format, value);
1840 dctx->format = (ZSTD_format_e)value;
1841 return 0;
1842 case ZSTD_d_stableOutBuffer:
1843 CHECK_DBOUNDS(ZSTD_d_stableOutBuffer, value);
1844 dctx->outBufferMode = (ZSTD_bufferMode_e)value;
1845 return 0;
1846 case ZSTD_d_forceIgnoreChecksum:
1847 CHECK_DBOUNDS(ZSTD_d_forceIgnoreChecksum, value);
1848 dctx->forceIgnoreChecksum = (ZSTD_forceIgnoreChecksum_e)value;
1849 return 0;
1850 case ZSTD_d_refMultipleDDicts:
1851 CHECK_DBOUNDS(ZSTD_d_refMultipleDDicts, value);
1852 if (dctx->staticSize != 0) {
1853 RETURN_ERROR(parameter_unsupported, "Static dctx does not support multiple DDicts!");
1854 }
1855 dctx->refMultipleDDicts = (ZSTD_refMultipleDDicts_e)value;
1856 return 0;
1857 case ZSTD_d_disableHuffmanAssembly:
1858 CHECK_DBOUNDS(ZSTD_d_disableHuffmanAssembly, value);
1859 dctx->disableHufAsm = value != 0;
1860 return 0;
1861 case ZSTD_d_maxBlockSize:
1862 if (value != 0) CHECK_DBOUNDS(ZSTD_d_maxBlockSize, value);
1863 dctx->maxBlockSizeParam = value;
1864 return 0;
1865 default:;
1866 }
1867 RETURN_ERROR(parameter_unsupported, "");
1868}
1869
1870size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset)
1871{
1872 if ( (reset == ZSTD_reset_session_only)
1873 || (reset == ZSTD_reset_session_and_parameters) ) {
1874 dctx->streamStage = zdss_init;
1875 dctx->noForwardProgress = 0;
1876 dctx->isFrameDecompression = 1;
1877 }
1878 if ( (reset == ZSTD_reset_parameters)
1879 || (reset == ZSTD_reset_session_and_parameters) ) {
1880 RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong, "");
1881 ZSTD_clearDict(dctx);
1882 ZSTD_DCtx_resetParameters(dctx);
1883 }
1884 return 0;
1885}
1886
1887
1888size_t ZSTD_sizeof_DStream(const ZSTD_DStream* dctx)
1889{
1890 return ZSTD_sizeof_DCtx(dctx);
1891}
1892
1893static size_t ZSTD_decodingBufferSize_internal(unsigned long long windowSize, unsigned long long frameContentSize, size_t blockSizeMax)
1894{
1895 size_t const blockSize = MIN((size_t)MIN(windowSize, ZSTD_BLOCKSIZE_MAX), blockSizeMax);
1896 /* We need blockSize + WILDCOPY_OVERLENGTH worth of buffer so that if a block
1897 * ends at windowSize + WILDCOPY_OVERLENGTH + 1 bytes, we can start writing
1898 * the block at the beginning of the output buffer, and maintain a full window.
1899 *
1900 * We need another blockSize worth of buffer so that we can store split
1901 * literals at the end of the block without overwriting the extDict window.
1902 */
1903 unsigned long long const neededRBSize = windowSize + (blockSize * 2) + (WILDCOPY_OVERLENGTH * 2);
1904 unsigned long long const neededSize = MIN(frameContentSize, neededRBSize);
1905 size_t const minRBSize = (size_t) neededSize;
1906 RETURN_ERROR_IF((unsigned long long)minRBSize != neededSize,
1907 frameParameter_windowTooLarge, "");
1908 return minRBSize;
1909}
1910
1911size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize)
1912{
1913 return ZSTD_decodingBufferSize_internal(windowSize, frameContentSize, ZSTD_BLOCKSIZE_MAX);
1914}
1915
1916size_t ZSTD_estimateDStreamSize(size_t windowSize)
1917{
1918 size_t const blockSize = MIN(windowSize, ZSTD_BLOCKSIZE_MAX);
1919 size_t const inBuffSize = blockSize; /* no block can be larger */
1920 size_t const outBuffSize = ZSTD_decodingBufferSize_min(windowSize, ZSTD_CONTENTSIZE_UNKNOWN);
1921 return ZSTD_estimateDCtxSize() + inBuffSize + outBuffSize;
1922}
1923
1924size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize)
1925{
1926 U32 const windowSizeMax = 1U << ZSTD_WINDOWLOG_MAX; /* note : should be user-selectable, but requires an additional parameter (or a dctx) */
1927 ZSTD_FrameHeader zfh;
1928 size_t const err = ZSTD_getFrameHeader(zfhPtr: &zfh, src, srcSize);
1929 if (ZSTD_isError(code: err)) return err;
1930 RETURN_ERROR_IF(err>0, srcSize_wrong, "");
1931 RETURN_ERROR_IF(zfh.windowSize > windowSizeMax,
1932 frameParameter_windowTooLarge, "");
1933 return ZSTD_estimateDStreamSize(windowSize: (size_t)zfh.windowSize);
1934}
1935
1936
1937/* ***** Decompression ***** */
1938
1939static int ZSTD_DCtx_isOverflow(ZSTD_DStream* zds, size_t const neededInBuffSize, size_t const neededOutBuffSize)
1940{
1941 return (zds->inBuffSize + zds->outBuffSize) >= (neededInBuffSize + neededOutBuffSize) * ZSTD_WORKSPACETOOLARGE_FACTOR;
1942}
1943
1944static void ZSTD_DCtx_updateOversizedDuration(ZSTD_DStream* zds, size_t const neededInBuffSize, size_t const neededOutBuffSize)
1945{
1946 if (ZSTD_DCtx_isOverflow(zds, neededInBuffSize, neededOutBuffSize))
1947 zds->oversizedDuration++;
1948 else
1949 zds->oversizedDuration = 0;
1950}
1951
1952static int ZSTD_DCtx_isOversizedTooLong(ZSTD_DStream* zds)
1953{
1954 return zds->oversizedDuration >= ZSTD_WORKSPACETOOLARGE_MAXDURATION;
1955}
1956
1957/* Checks that the output buffer hasn't changed if ZSTD_obm_stable is used. */
1958static size_t ZSTD_checkOutBuffer(ZSTD_DStream const* zds, ZSTD_outBuffer const* output)
1959{
1960 ZSTD_outBuffer const expect = zds->expectedOutBuffer;
1961 /* No requirement when ZSTD_obm_stable is not enabled. */
1962 if (zds->outBufferMode != ZSTD_bm_stable)
1963 return 0;
1964 /* Any buffer is allowed in zdss_init, this must be the same for every other call until
1965 * the context is reset.
1966 */
1967 if (zds->streamStage == zdss_init)
1968 return 0;
1969 /* The buffer must match our expectation exactly. */
1970 if (expect.dst == output->dst && expect.pos == output->pos && expect.size == output->size)
1971 return 0;
1972 RETURN_ERROR(dstBuffer_wrong, "ZSTD_d_stableOutBuffer enabled but output differs!");
1973}
1974
1975/* Calls ZSTD_decompressContinue() with the right parameters for ZSTD_decompressStream()
1976 * and updates the stage and the output buffer state. This call is extracted so it can be
1977 * used both when reading directly from the ZSTD_inBuffer, and in buffered input mode.
1978 * NOTE: You must break after calling this function since the streamStage is modified.
1979 */
1980static size_t ZSTD_decompressContinueStream(
1981 ZSTD_DStream* zds, char** op, char* oend,
1982 void const* src, size_t srcSize) {
1983 int const isSkipFrame = ZSTD_isSkipFrame(dctx: zds);
1984 if (zds->outBufferMode == ZSTD_bm_buffered) {
1985 size_t const dstSize = isSkipFrame ? 0 : zds->outBuffSize - zds->outStart;
1986 size_t const decodedSize = ZSTD_decompressContinue(dctx: zds,
1987 dst: zds->outBuff + zds->outStart, dstCapacity: dstSize, src, srcSize);
1988 FORWARD_IF_ERROR(decodedSize, "");
1989 if (!decodedSize && !isSkipFrame) {
1990 zds->streamStage = zdss_read;
1991 } else {
1992 zds->outEnd = zds->outStart + decodedSize;
1993 zds->streamStage = zdss_flush;
1994 }
1995 } else {
1996 /* Write directly into the output buffer */
1997 size_t const dstSize = isSkipFrame ? 0 : (size_t)(oend - *op);
1998 size_t const decodedSize = ZSTD_decompressContinue(dctx: zds, dst: *op, dstCapacity: dstSize, src, srcSize);
1999 FORWARD_IF_ERROR(decodedSize, "");
2000 *op += decodedSize;
2001 /* Flushing is not needed. */
2002 zds->streamStage = zdss_read;
2003 assert(*op <= oend);
2004 assert(zds->outBufferMode == ZSTD_bm_stable);
2005 }
2006 return 0;
2007}
2008
2009size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
2010{
2011 const char* const src = (const char*)input->src;
2012 const char* const istart = input->pos != 0 ? src + input->pos : src;
2013 const char* const iend = input->size != 0 ? src + input->size : src;
2014 const char* ip = istart;
2015 char* const dst = (char*)output->dst;
2016 char* const ostart = output->pos != 0 ? dst + output->pos : dst;
2017 char* const oend = output->size != 0 ? dst + output->size : dst;
2018 char* op = ostart;
2019 U32 someMoreWork = 1;
2020
2021 DEBUGLOG(5, "ZSTD_decompressStream");
2022 assert(zds != NULL);
2023 RETURN_ERROR_IF(
2024 input->pos > input->size,
2025 srcSize_wrong,
2026 "forbidden. in: pos: %u vs size: %u",
2027 (U32)input->pos, (U32)input->size);
2028 RETURN_ERROR_IF(
2029 output->pos > output->size,
2030 dstSize_tooSmall,
2031 "forbidden. out: pos: %u vs size: %u",
2032 (U32)output->pos, (U32)output->size);
2033 DEBUGLOG(5, "input size : %u", (U32)(input->size - input->pos));
2034 FORWARD_IF_ERROR(ZSTD_checkOutBuffer(zds, output), "");
2035
2036 while (someMoreWork) {
2037 switch(zds->streamStage)
2038 {
2039 case zdss_init :
2040 DEBUGLOG(5, "stage zdss_init => transparent reset ");
2041 zds->streamStage = zdss_loadHeader;
2042 zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
2043 zds->hostageByte = 0;
2044 zds->expectedOutBuffer = *output;
2045 ZSTD_FALLTHROUGH;
2046
2047 case zdss_loadHeader :
2048 DEBUGLOG(5, "stage zdss_loadHeader (srcSize : %u)", (U32)(iend - ip));
2049 { size_t const hSize = ZSTD_getFrameHeader_advanced(zfhPtr: &zds->fParams, src: zds->headerBuffer, srcSize: zds->lhSize, format: zds->format);
2050 if (zds->refMultipleDDicts && zds->ddictSet) {
2051 ZSTD_DCtx_selectFrameDDict(dctx: zds);
2052 }
2053 if (ZSTD_isError(code: hSize)) {
2054 return hSize; /* error */
2055 }
2056 if (hSize != 0) { /* need more input */
2057 size_t const toLoad = hSize - zds->lhSize; /* if hSize!=0, hSize > zds->lhSize */
2058 size_t const remainingInput = (size_t)(iend-ip);
2059 assert(iend >= ip);
2060 if (toLoad > remainingInput) { /* not enough input to load full header */
2061 if (remainingInput > 0) {
2062 ZSTD_memcpy(zds->headerBuffer + zds->lhSize, ip, remainingInput);
2063 zds->lhSize += remainingInput;
2064 }
2065 input->pos = input->size;
2066 /* check first few bytes */
2067 FORWARD_IF_ERROR(
2068 ZSTD_getFrameHeader_advanced(&zds->fParams, zds->headerBuffer, zds->lhSize, zds->format),
2069 "First few bytes detected incorrect" );
2070 /* return hint input size */
2071 return (MAX((size_t)ZSTD_FRAMEHEADERSIZE_MIN(zds->format), hSize) - zds->lhSize) + ZSTD_blockHeaderSize; /* remaining header bytes + next block header */
2072 }
2073 assert(ip != NULL);
2074 ZSTD_memcpy(zds->headerBuffer + zds->lhSize, ip, toLoad); zds->lhSize = hSize; ip += toLoad;
2075 break;
2076 } }
2077
2078 /* check for single-pass mode opportunity */
2079 if (zds->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN
2080 && zds->fParams.frameType != ZSTD_skippableFrame
2081 && (U64)(size_t)(oend-op) >= zds->fParams.frameContentSize) {
2082 size_t const cSize = ZSTD_findFrameCompressedSize_advanced(src: istart, srcSize: (size_t)(iend-istart), format: zds->format);
2083 if (cSize <= (size_t)(iend-istart)) {
2084 /* shortcut : using single-pass mode */
2085 size_t const decompressedSize = ZSTD_decompress_usingDDict(dctx: zds, dst: op, dstCapacity: (size_t)(oend-op), src: istart, srcSize: cSize, ddict: ZSTD_getDDict(dctx: zds));
2086 if (ZSTD_isError(code: decompressedSize)) return decompressedSize;
2087 DEBUGLOG(4, "shortcut to single-pass ZSTD_decompress_usingDDict()");
2088 assert(istart != NULL);
2089 ip = istart + cSize;
2090 op = op ? op + decompressedSize : op; /* can occur if frameContentSize = 0 (empty frame) */
2091 zds->expected = 0;
2092 zds->streamStage = zdss_init;
2093 someMoreWork = 0;
2094 break;
2095 } }
2096
2097 /* Check output buffer is large enough for ZSTD_odm_stable. */
2098 if (zds->outBufferMode == ZSTD_bm_stable
2099 && zds->fParams.frameType != ZSTD_skippableFrame
2100 && zds->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN
2101 && (U64)(size_t)(oend-op) < zds->fParams.frameContentSize) {
2102 RETURN_ERROR(dstSize_tooSmall, "ZSTD_obm_stable passed but ZSTD_outBuffer is too small");
2103 }
2104
2105 /* Consume header (see ZSTDds_decodeFrameHeader) */
2106 DEBUGLOG(4, "Consume header");
2107 FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(zds, ZSTD_getDDict(zds)), "");
2108
2109 if (zds->format == ZSTD_f_zstd1
2110 && (MEM_readLE32(memPtr: zds->headerBuffer) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */
2111 zds->expected = MEM_readLE32(memPtr: zds->headerBuffer + ZSTD_FRAMEIDSIZE);
2112 zds->stage = ZSTDds_skipFrame;
2113 } else {
2114 FORWARD_IF_ERROR(ZSTD_decodeFrameHeader(zds, zds->headerBuffer, zds->lhSize), "");
2115 zds->expected = ZSTD_blockHeaderSize;
2116 zds->stage = ZSTDds_decodeBlockHeader;
2117 }
2118
2119 /* control buffer memory usage */
2120 DEBUGLOG(4, "Control max memory usage (%u KB <= max %u KB)",
2121 (U32)(zds->fParams.windowSize >>10),
2122 (U32)(zds->maxWindowSize >> 10) );
2123 zds->fParams.windowSize = MAX(zds->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN);
2124 RETURN_ERROR_IF(zds->fParams.windowSize > zds->maxWindowSize,
2125 frameParameter_windowTooLarge, "");
2126 if (zds->maxBlockSizeParam != 0)
2127 zds->fParams.blockSizeMax = MIN(zds->fParams.blockSizeMax, (unsigned)zds->maxBlockSizeParam);
2128
2129 /* Adapt buffer sizes to frame header instructions */
2130 { size_t const neededInBuffSize = MAX(zds->fParams.blockSizeMax, 4 /* frame checksum */);
2131 size_t const neededOutBuffSize = zds->outBufferMode == ZSTD_bm_buffered
2132 ? ZSTD_decodingBufferSize_internal(windowSize: zds->fParams.windowSize, frameContentSize: zds->fParams.frameContentSize, blockSizeMax: zds->fParams.blockSizeMax)
2133 : 0;
2134
2135 ZSTD_DCtx_updateOversizedDuration(zds, neededInBuffSize, neededOutBuffSize);
2136
2137 { int const tooSmall = (zds->inBuffSize < neededInBuffSize) || (zds->outBuffSize < neededOutBuffSize);
2138 int const tooLarge = ZSTD_DCtx_isOversizedTooLong(zds);
2139
2140 if (tooSmall || tooLarge) {
2141 size_t const bufferSize = neededInBuffSize + neededOutBuffSize;
2142 DEBUGLOG(4, "inBuff : from %u to %u",
2143 (U32)zds->inBuffSize, (U32)neededInBuffSize);
2144 DEBUGLOG(4, "outBuff : from %u to %u",
2145 (U32)zds->outBuffSize, (U32)neededOutBuffSize);
2146 if (zds->staticSize) { /* static DCtx */
2147 DEBUGLOG(4, "staticSize : %u", (U32)zds->staticSize);
2148 assert(zds->staticSize >= sizeof(ZSTD_DCtx)); /* controlled at init */
2149 RETURN_ERROR_IF(
2150 bufferSize > zds->staticSize - sizeof(ZSTD_DCtx),
2151 memory_allocation, "");
2152 } else {
2153 ZSTD_customFree(ptr: zds->inBuff, customMem: zds->customMem);
2154 zds->inBuffSize = 0;
2155 zds->outBuffSize = 0;
2156 zds->inBuff = (char*)ZSTD_customMalloc(size: bufferSize, customMem: zds->customMem);
2157 RETURN_ERROR_IF(zds->inBuff == NULL, memory_allocation, "");
2158 }
2159 zds->inBuffSize = neededInBuffSize;
2160 zds->outBuff = zds->inBuff + zds->inBuffSize;
2161 zds->outBuffSize = neededOutBuffSize;
2162 } } }
2163 zds->streamStage = zdss_read;
2164 ZSTD_FALLTHROUGH;
2165
2166 case zdss_read:
2167 DEBUGLOG(5, "stage zdss_read");
2168 { size_t const neededInSize = ZSTD_nextSrcSizeToDecompressWithInputSize(dctx: zds, inputSize: (size_t)(iend - ip));
2169 DEBUGLOG(5, "neededInSize = %u", (U32)neededInSize);
2170 if (neededInSize==0) { /* end of frame */
2171 zds->streamStage = zdss_init;
2172 someMoreWork = 0;
2173 break;
2174 }
2175 if ((size_t)(iend-ip) >= neededInSize) { /* decode directly from src */
2176 FORWARD_IF_ERROR(ZSTD_decompressContinueStream(zds, &op, oend, ip, neededInSize), "");
2177 assert(ip != NULL);
2178 ip += neededInSize;
2179 /* Function modifies the stage so we must break */
2180 break;
2181 } }
2182 if (ip==iend) { someMoreWork = 0; break; } /* no more input */
2183 zds->streamStage = zdss_load;
2184 ZSTD_FALLTHROUGH;
2185
2186 case zdss_load:
2187 { size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(dctx: zds);
2188 size_t const toLoad = neededInSize - zds->inPos;
2189 int const isSkipFrame = ZSTD_isSkipFrame(dctx: zds);
2190 size_t loadedSize;
2191 /* At this point we shouldn't be decompressing a block that we can stream. */
2192 assert(neededInSize == ZSTD_nextSrcSizeToDecompressWithInputSize(zds, (size_t)(iend - ip)));
2193 if (isSkipFrame) {
2194 loadedSize = MIN(toLoad, (size_t)(iend-ip));
2195 } else {
2196 RETURN_ERROR_IF(toLoad > zds->inBuffSize - zds->inPos,
2197 corruption_detected,
2198 "should never happen");
2199 loadedSize = ZSTD_limitCopy(dst: zds->inBuff + zds->inPos, dstCapacity: toLoad, src: ip, srcSize: (size_t)(iend-ip));
2200 }
2201 if (loadedSize != 0) {
2202 /* ip may be NULL */
2203 ip += loadedSize;
2204 zds->inPos += loadedSize;
2205 }
2206 if (loadedSize < toLoad) { someMoreWork = 0; break; } /* not enough input, wait for more */
2207
2208 /* decode loaded input */
2209 zds->inPos = 0; /* input is consumed */
2210 FORWARD_IF_ERROR(ZSTD_decompressContinueStream(zds, &op, oend, zds->inBuff, neededInSize), "");
2211 /* Function modifies the stage so we must break */
2212 break;
2213 }
2214 case zdss_flush:
2215 {
2216 size_t const toFlushSize = zds->outEnd - zds->outStart;
2217 size_t const flushedSize = ZSTD_limitCopy(dst: op, dstCapacity: (size_t)(oend-op), src: zds->outBuff + zds->outStart, srcSize: toFlushSize);
2218
2219 op = op ? op + flushedSize : op;
2220
2221 zds->outStart += flushedSize;
2222 if (flushedSize == toFlushSize) { /* flush completed */
2223 zds->streamStage = zdss_read;
2224 if ( (zds->outBuffSize < zds->fParams.frameContentSize)
2225 && (zds->outStart + zds->fParams.blockSizeMax > zds->outBuffSize) ) {
2226 DEBUGLOG(5, "restart filling outBuff from beginning (left:%i, needed:%u)",
2227 (int)(zds->outBuffSize - zds->outStart),
2228 (U32)zds->fParams.blockSizeMax);
2229 zds->outStart = zds->outEnd = 0;
2230 }
2231 break;
2232 } }
2233 /* cannot complete flush */
2234 someMoreWork = 0;
2235 break;
2236
2237 default:
2238 assert(0); /* impossible */
2239 RETURN_ERROR(GENERIC, "impossible to reach"); /* some compilers require default to do something */
2240 } }
2241
2242 /* result */
2243 input->pos = (size_t)(ip - (const char*)(input->src));
2244 output->pos = (size_t)(op - (char*)(output->dst));
2245
2246 /* Update the expected output buffer for ZSTD_obm_stable. */
2247 zds->expectedOutBuffer = *output;
2248
2249 if ((ip==istart) && (op==ostart)) { /* no forward progress */
2250 zds->noForwardProgress ++;
2251 if (zds->noForwardProgress >= ZSTD_NO_FORWARD_PROGRESS_MAX) {
2252 RETURN_ERROR_IF(op==oend, noForwardProgress_destFull, "");
2253 RETURN_ERROR_IF(ip==iend, noForwardProgress_inputEmpty, "");
2254 assert(0);
2255 }
2256 } else {
2257 zds->noForwardProgress = 0;
2258 }
2259 { size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(dctx: zds);
2260 if (!nextSrcSizeHint) { /* frame fully decoded */
2261 if (zds->outEnd == zds->outStart) { /* output fully flushed */
2262 if (zds->hostageByte) {
2263 if (input->pos >= input->size) {
2264 /* can't release hostage (not present) */
2265 zds->streamStage = zdss_read;
2266 return 1;
2267 }
2268 input->pos++; /* release hostage */
2269 } /* zds->hostageByte */
2270 return 0;
2271 } /* zds->outEnd == zds->outStart */
2272 if (!zds->hostageByte) { /* output not fully flushed; keep last byte as hostage; will be released when all output is flushed */
2273 input->pos--; /* note : pos > 0, otherwise, impossible to finish reading last block */
2274 zds->hostageByte=1;
2275 }
2276 return 1;
2277 } /* nextSrcSizeHint==0 */
2278 nextSrcSizeHint += ZSTD_blockHeaderSize * (ZSTD_nextInputType(dctx: zds) == ZSTDnit_block); /* preload header of next block */
2279 assert(zds->inPos <= nextSrcSizeHint);
2280 nextSrcSizeHint -= zds->inPos; /* part already loaded*/
2281 return nextSrcSizeHint;
2282 }
2283}
2284
2285size_t ZSTD_decompressStream_simpleArgs (
2286 ZSTD_DCtx* dctx,
2287 void* dst, size_t dstCapacity, size_t* dstPos,
2288 const void* src, size_t srcSize, size_t* srcPos)
2289{
2290 ZSTD_outBuffer output;
2291 ZSTD_inBuffer input;
2292 output.dst = dst;
2293 output.size = dstCapacity;
2294 output.pos = *dstPos;
2295 input.src = src;
2296 input.size = srcSize;
2297 input.pos = *srcPos;
2298 { size_t const cErr = ZSTD_decompressStream(zds: dctx, output: &output, input: &input);
2299 *dstPos = output.pos;
2300 *srcPos = input.pos;
2301 return cErr;
2302 }
2303}
2304