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648db22b 1/*
2 * Copyright (c) Meta Platforms, Inc. and affiliates.
3 * All rights reserved.
4 *
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
9 */
10#if defined (__cplusplus)
11extern "C" {
12#endif
13
14#ifndef ZSTD_H_235446
15#define ZSTD_H_235446
16
17/* ====== Dependencies ======*/
18#include <limits.h> /* INT_MAX */
19#include <stddef.h> /* size_t */
20
21
22/* ===== ZSTDLIB_API : control library symbols visibility ===== */
23#ifndef ZSTDLIB_VISIBLE
24 /* Backwards compatibility with old macro name */
25# ifdef ZSTDLIB_VISIBILITY
26# define ZSTDLIB_VISIBLE ZSTDLIB_VISIBILITY
27# elif defined(__GNUC__) && (__GNUC__ >= 4) && !defined(__MINGW32__)
28# define ZSTDLIB_VISIBLE __attribute__ ((visibility ("default")))
29# else
30# define ZSTDLIB_VISIBLE
31# endif
32#endif
33
34#ifndef ZSTDLIB_HIDDEN
35# if defined(__GNUC__) && (__GNUC__ >= 4) && !defined(__MINGW32__)
36# define ZSTDLIB_HIDDEN __attribute__ ((visibility ("hidden")))
37# else
38# define ZSTDLIB_HIDDEN
39# endif
40#endif
41
42#if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
43# define ZSTDLIB_API __declspec(dllexport) ZSTDLIB_VISIBLE
44#elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1)
45# define ZSTDLIB_API __declspec(dllimport) ZSTDLIB_VISIBLE /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/
46#else
47# define ZSTDLIB_API ZSTDLIB_VISIBLE
48#endif
49
50/* Deprecation warnings :
51 * Should these warnings be a problem, it is generally possible to disable them,
52 * typically with -Wno-deprecated-declarations for gcc or _CRT_SECURE_NO_WARNINGS in Visual.
53 * Otherwise, it's also possible to define ZSTD_DISABLE_DEPRECATE_WARNINGS.
54 */
55#ifdef ZSTD_DISABLE_DEPRECATE_WARNINGS
56# define ZSTD_DEPRECATED(message) /* disable deprecation warnings */
57#else
58# if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */
59# define ZSTD_DEPRECATED(message) [[deprecated(message)]]
60# elif (defined(GNUC) && (GNUC > 4 || (GNUC == 4 && GNUC_MINOR >= 5))) || defined(__clang__)
61# define ZSTD_DEPRECATED(message) __attribute__((deprecated(message)))
62# elif defined(__GNUC__) && (__GNUC__ >= 3)
63# define ZSTD_DEPRECATED(message) __attribute__((deprecated))
64# elif defined(_MSC_VER)
65# define ZSTD_DEPRECATED(message) __declspec(deprecated(message))
66# else
67# pragma message("WARNING: You need to implement ZSTD_DEPRECATED for this compiler")
68# define ZSTD_DEPRECATED(message)
69# endif
70#endif /* ZSTD_DISABLE_DEPRECATE_WARNINGS */
71
72
73/*******************************************************************************
74 Introduction
75
76 zstd, short for Zstandard, is a fast lossless compression algorithm, targeting
77 real-time compression scenarios at zlib-level and better compression ratios.
78 The zstd compression library provides in-memory compression and decompression
79 functions.
80
81 The library supports regular compression levels from 1 up to ZSTD_maxCLevel(),
82 which is currently 22. Levels >= 20, labeled `--ultra`, should be used with
83 caution, as they require more memory. The library also offers negative
84 compression levels, which extend the range of speed vs. ratio preferences.
85 The lower the level, the faster the speed (at the cost of compression).
86
87 Compression can be done in:
88 - a single step (described as Simple API)
89 - a single step, reusing a context (described as Explicit context)
90 - unbounded multiple steps (described as Streaming compression)
91
92 The compression ratio achievable on small data can be highly improved using
93 a dictionary. Dictionary compression can be performed in:
94 - a single step (described as Simple dictionary API)
95 - a single step, reusing a dictionary (described as Bulk-processing
96 dictionary API)
97
98 Advanced experimental functions can be accessed using
99 `#define ZSTD_STATIC_LINKING_ONLY` before including zstd.h.
100
101 Advanced experimental APIs should never be used with a dynamically-linked
102 library. They are not "stable"; their definitions or signatures may change in
103 the future. Only static linking is allowed.
104*******************************************************************************/
105
106/*------ Version ------*/
107#define ZSTD_VERSION_MAJOR 1
108#define ZSTD_VERSION_MINOR 5
f535537f 109#define ZSTD_VERSION_RELEASE 6
648db22b 110#define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE)
111
112/*! ZSTD_versionNumber() :
113 * Return runtime library version, the value is (MAJOR*100*100 + MINOR*100 + RELEASE). */
114ZSTDLIB_API unsigned ZSTD_versionNumber(void);
115
116#define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE
117#define ZSTD_QUOTE(str) #str
118#define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str)
119#define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION)
120
121/*! ZSTD_versionString() :
122 * Return runtime library version, like "1.4.5". Requires v1.3.0+. */
123ZSTDLIB_API const char* ZSTD_versionString(void);
124
125/* *************************************
126 * Default constant
127 ***************************************/
128#ifndef ZSTD_CLEVEL_DEFAULT
129# define ZSTD_CLEVEL_DEFAULT 3
130#endif
131
132/* *************************************
133 * Constants
134 ***************************************/
135
136/* All magic numbers are supposed read/written to/from files/memory using little-endian convention */
137#define ZSTD_MAGICNUMBER 0xFD2FB528 /* valid since v0.8.0 */
138#define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* valid since v0.7.0 */
139#define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50 /* all 16 values, from 0x184D2A50 to 0x184D2A5F, signal the beginning of a skippable frame */
140#define ZSTD_MAGIC_SKIPPABLE_MASK 0xFFFFFFF0
141
142#define ZSTD_BLOCKSIZELOG_MAX 17
143#define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX)
144
145
146/***************************************
147* Simple API
148***************************************/
149/*! ZSTD_compress() :
150 * Compresses `src` content as a single zstd compressed frame into already allocated `dst`.
151 * NOTE: Providing `dstCapacity >= ZSTD_compressBound(srcSize)` guarantees that zstd will have
152 * enough space to successfully compress the data.
153 * @return : compressed size written into `dst` (<= `dstCapacity),
154 * or an error code if it fails (which can be tested using ZSTD_isError()). */
155ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity,
156 const void* src, size_t srcSize,
157 int compressionLevel);
158
159/*! ZSTD_decompress() :
160 * `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames.
161 * `dstCapacity` is an upper bound of originalSize to regenerate.
162 * If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data.
163 * @return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
164 * or an errorCode if it fails (which can be tested using ZSTD_isError()). */
165ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity,
166 const void* src, size_t compressedSize);
167
168/*! ZSTD_getFrameContentSize() : requires v1.3.0+
169 * `src` should point to the start of a ZSTD encoded frame.
170 * `srcSize` must be at least as large as the frame header.
171 * hint : any size >= `ZSTD_frameHeaderSize_max` is large enough.
172 * @return : - decompressed size of `src` frame content, if known
173 * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
174 * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small)
175 * note 1 : a 0 return value means the frame is valid but "empty".
176 * note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode.
177 * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.
178 * In which case, it's necessary to use streaming mode to decompress data.
179 * Optionally, application can rely on some implicit limit,
180 * as ZSTD_decompress() only needs an upper bound of decompressed size.
181 * (For example, data could be necessarily cut into blocks <= 16 KB).
182 * note 3 : decompressed size is always present when compression is completed using single-pass functions,
183 * such as ZSTD_compress(), ZSTD_compressCCtx() ZSTD_compress_usingDict() or ZSTD_compress_usingCDict().
184 * note 4 : decompressed size can be very large (64-bits value),
185 * potentially larger than what local system can handle as a single memory segment.
186 * In which case, it's necessary to use streaming mode to decompress data.
187 * note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified.
188 * Always ensure return value fits within application's authorized limits.
189 * Each application can set its own limits.
190 * note 6 : This function replaces ZSTD_getDecompressedSize() */
191#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)
192#define ZSTD_CONTENTSIZE_ERROR (0ULL - 2)
193ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);
194
195/*! ZSTD_getDecompressedSize() :
196 * NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize().
197 * Both functions work the same way, but ZSTD_getDecompressedSize() blends
198 * "empty", "unknown" and "error" results to the same return value (0),
199 * while ZSTD_getFrameContentSize() gives them separate return values.
200 * @return : decompressed size of `src` frame content _if known and not empty_, 0 otherwise. */
201ZSTD_DEPRECATED("Replaced by ZSTD_getFrameContentSize")
202ZSTDLIB_API
203unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize);
204
205/*! ZSTD_findFrameCompressedSize() : Requires v1.4.0+
206 * `src` should point to the start of a ZSTD frame or skippable frame.
207 * `srcSize` must be >= first frame size
208 * @return : the compressed size of the first frame starting at `src`,
209 * suitable to pass as `srcSize` to `ZSTD_decompress` or similar,
210 * or an error code if input is invalid */
211ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize);
212
213
214/*====== Helper functions ======*/
215/* ZSTD_compressBound() :
216 * maximum compressed size in worst case single-pass scenario.
217 * When invoking `ZSTD_compress()` or any other one-pass compression function,
218 * it's recommended to provide @dstCapacity >= ZSTD_compressBound(srcSize)
219 * as it eliminates one potential failure scenario,
220 * aka not enough room in dst buffer to write the compressed frame.
221 * Note : ZSTD_compressBound() itself can fail, if @srcSize > ZSTD_MAX_INPUT_SIZE .
222 * In which case, ZSTD_compressBound() will return an error code
223 * which can be tested using ZSTD_isError().
224 *
225 * ZSTD_COMPRESSBOUND() :
226 * same as ZSTD_compressBound(), but as a macro.
227 * It can be used to produce constants, which can be useful for static allocation,
228 * for example to size a static array on stack.
229 * Will produce constant value 0 if srcSize too large.
230 */
f535537f 231#define ZSTD_MAX_INPUT_SIZE ((sizeof(size_t)==8) ? 0xFF00FF00FF00FF00ULL : 0xFF00FF00U)
648db22b 232#define ZSTD_COMPRESSBOUND(srcSize) (((size_t)(srcSize) >= ZSTD_MAX_INPUT_SIZE) ? 0 : (srcSize) + ((srcSize)>>8) + (((srcSize) < (128<<10)) ? (((128<<10) - (srcSize)) >> 11) /* margin, from 64 to 0 */ : 0)) /* this formula ensures that bound(A) + bound(B) <= bound(A+B) as long as A and B >= 128 KB */
233ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case single-pass scenario */
234/* ZSTD_isError() :
235 * Most ZSTD_* functions returning a size_t value can be tested for error,
236 * using ZSTD_isError().
237 * @return 1 if error, 0 otherwise
238 */
239ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */
240ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */
241ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed, requires v1.4.0+ */
242ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */
243ZSTDLIB_API int ZSTD_defaultCLevel(void); /*!< default compression level, specified by ZSTD_CLEVEL_DEFAULT, requires v1.5.0+ */
244
245
246/***************************************
247* Explicit context
248***************************************/
249/*= Compression context
250 * When compressing many times,
251 * it is recommended to allocate a context just once,
f535537f 252 * and reuse it for each successive compression operation.
648db22b 253 * This will make workload friendlier for system's memory.
254 * Note : re-using context is just a speed / resource optimization.
255 * It doesn't change the compression ratio, which remains identical.
256 * Note 2 : In multi-threaded environments,
257 * use one different context per thread for parallel execution.
258 */
259typedef struct ZSTD_CCtx_s ZSTD_CCtx;
260ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void);
261ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); /* accept NULL pointer */
262
263/*! ZSTD_compressCCtx() :
264 * Same as ZSTD_compress(), using an explicit ZSTD_CCtx.
f535537f 265 * Important : in order to mirror `ZSTD_compress()` behavior,
266 * this function compresses at the requested compression level,
267 * __ignoring any other advanced parameter__ .
648db22b 268 * If any advanced parameter was set using the advanced API,
269 * they will all be reset. Only `compressionLevel` remains.
270 */
271ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* cctx,
272 void* dst, size_t dstCapacity,
273 const void* src, size_t srcSize,
274 int compressionLevel);
275
276/*= Decompression context
277 * When decompressing many times,
278 * it is recommended to allocate a context only once,
f535537f 279 * and reuse it for each successive compression operation.
648db22b 280 * This will make workload friendlier for system's memory.
281 * Use one context per thread for parallel execution. */
282typedef struct ZSTD_DCtx_s ZSTD_DCtx;
283ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void);
284ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx); /* accept NULL pointer */
285
286/*! ZSTD_decompressDCtx() :
287 * Same as ZSTD_decompress(),
288 * requires an allocated ZSTD_DCtx.
f535537f 289 * Compatible with sticky parameters (see below).
648db22b 290 */
291ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx,
292 void* dst, size_t dstCapacity,
293 const void* src, size_t srcSize);
294
295
296/*********************************************
297* Advanced compression API (Requires v1.4.0+)
298**********************************************/
299
300/* API design :
301 * Parameters are pushed one by one into an existing context,
302 * using ZSTD_CCtx_set*() functions.
303 * Pushed parameters are sticky : they are valid for next compressed frame, and any subsequent frame.
304 * "sticky" parameters are applicable to `ZSTD_compress2()` and `ZSTD_compressStream*()` !
f535537f 305 * __They do not apply to one-shot variants such as ZSTD_compressCCtx()__ .
648db22b 306 *
307 * It's possible to reset all parameters to "default" using ZSTD_CCtx_reset().
308 *
309 * This API supersedes all other "advanced" API entry points in the experimental section.
f535537f 310 * In the future, we expect to remove API entry points from experimental which are redundant with this API.
648db22b 311 */
312
313
314/* Compression strategies, listed from fastest to strongest */
315typedef enum { ZSTD_fast=1,
316 ZSTD_dfast=2,
317 ZSTD_greedy=3,
318 ZSTD_lazy=4,
319 ZSTD_lazy2=5,
320 ZSTD_btlazy2=6,
321 ZSTD_btopt=7,
322 ZSTD_btultra=8,
323 ZSTD_btultra2=9
324 /* note : new strategies _might_ be added in the future.
325 Only the order (from fast to strong) is guaranteed */
326} ZSTD_strategy;
327
328typedef enum {
329
330 /* compression parameters
331 * Note: When compressing with a ZSTD_CDict these parameters are superseded
332 * by the parameters used to construct the ZSTD_CDict.
333 * See ZSTD_CCtx_refCDict() for more info (superseded-by-cdict). */
334 ZSTD_c_compressionLevel=100, /* Set compression parameters according to pre-defined cLevel table.
335 * Note that exact compression parameters are dynamically determined,
336 * depending on both compression level and srcSize (when known).
337 * Default level is ZSTD_CLEVEL_DEFAULT==3.
338 * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT.
339 * Note 1 : it's possible to pass a negative compression level.
340 * Note 2 : setting a level does not automatically set all other compression parameters
341 * to default. Setting this will however eventually dynamically impact the compression
342 * parameters which have not been manually set. The manually set
343 * ones will 'stick'. */
344 /* Advanced compression parameters :
345 * It's possible to pin down compression parameters to some specific values.
346 * In which case, these values are no longer dynamically selected by the compressor */
347 ZSTD_c_windowLog=101, /* Maximum allowed back-reference distance, expressed as power of 2.
348 * This will set a memory budget for streaming decompression,
349 * with larger values requiring more memory
350 * and typically compressing more.
351 * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX.
352 * Special: value 0 means "use default windowLog".
353 * Note: Using a windowLog greater than ZSTD_WINDOWLOG_LIMIT_DEFAULT
354 * requires explicitly allowing such size at streaming decompression stage. */
355 ZSTD_c_hashLog=102, /* Size of the initial probe table, as a power of 2.
356 * Resulting memory usage is (1 << (hashLog+2)).
357 * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX.
358 * Larger tables improve compression ratio of strategies <= dFast,
359 * and improve speed of strategies > dFast.
360 * Special: value 0 means "use default hashLog". */
361 ZSTD_c_chainLog=103, /* Size of the multi-probe search table, as a power of 2.
362 * Resulting memory usage is (1 << (chainLog+2)).
363 * Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX.
364 * Larger tables result in better and slower compression.
365 * This parameter is useless for "fast" strategy.
366 * It's still useful when using "dfast" strategy,
367 * in which case it defines a secondary probe table.
368 * Special: value 0 means "use default chainLog". */
369 ZSTD_c_searchLog=104, /* Number of search attempts, as a power of 2.
370 * More attempts result in better and slower compression.
371 * This parameter is useless for "fast" and "dFast" strategies.
372 * Special: value 0 means "use default searchLog". */
373 ZSTD_c_minMatch=105, /* Minimum size of searched matches.
374 * Note that Zstandard can still find matches of smaller size,
375 * it just tweaks its search algorithm to look for this size and larger.
376 * Larger values increase compression and decompression speed, but decrease ratio.
377 * Must be clamped between ZSTD_MINMATCH_MIN and ZSTD_MINMATCH_MAX.
378 * Note that currently, for all strategies < btopt, effective minimum is 4.
379 * , for all strategies > fast, effective maximum is 6.
380 * Special: value 0 means "use default minMatchLength". */
381 ZSTD_c_targetLength=106, /* Impact of this field depends on strategy.
382 * For strategies btopt, btultra & btultra2:
383 * Length of Match considered "good enough" to stop search.
384 * Larger values make compression stronger, and slower.
385 * For strategy fast:
386 * Distance between match sampling.
387 * Larger values make compression faster, and weaker.
388 * Special: value 0 means "use default targetLength". */
389 ZSTD_c_strategy=107, /* See ZSTD_strategy enum definition.
390 * The higher the value of selected strategy, the more complex it is,
391 * resulting in stronger and slower compression.
392 * Special: value 0 means "use default strategy". */
f535537f 393
394 ZSTD_c_targetCBlockSize=130, /* v1.5.6+
395 * Attempts to fit compressed block size into approximatively targetCBlockSize.
396 * Bound by ZSTD_TARGETCBLOCKSIZE_MIN and ZSTD_TARGETCBLOCKSIZE_MAX.
397 * Note that it's not a guarantee, just a convergence target (default:0).
398 * No target when targetCBlockSize == 0.
399 * This is helpful in low bandwidth streaming environments to improve end-to-end latency,
400 * when a client can make use of partial documents (a prominent example being Chrome).
401 * Note: this parameter is stable since v1.5.6.
402 * It was present as an experimental parameter in earlier versions,
403 * but it's not recommended using it with earlier library versions
404 * due to massive performance regressions.
405 */
648db22b 406 /* LDM mode parameters */
407 ZSTD_c_enableLongDistanceMatching=160, /* Enable long distance matching.
408 * This parameter is designed to improve compression ratio
409 * for large inputs, by finding large matches at long distance.
410 * It increases memory usage and window size.
411 * Note: enabling this parameter increases default ZSTD_c_windowLog to 128 MB
412 * except when expressly set to a different value.
413 * Note: will be enabled by default if ZSTD_c_windowLog >= 128 MB and
414 * compression strategy >= ZSTD_btopt (== compression level 16+) */
415 ZSTD_c_ldmHashLog=161, /* Size of the table for long distance matching, as a power of 2.
416 * Larger values increase memory usage and compression ratio,
417 * but decrease compression speed.
418 * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX
419 * default: windowlog - 7.
420 * Special: value 0 means "automatically determine hashlog". */
421 ZSTD_c_ldmMinMatch=162, /* Minimum match size for long distance matcher.
422 * Larger/too small values usually decrease compression ratio.
423 * Must be clamped between ZSTD_LDM_MINMATCH_MIN and ZSTD_LDM_MINMATCH_MAX.
424 * Special: value 0 means "use default value" (default: 64). */
425 ZSTD_c_ldmBucketSizeLog=163, /* Log size of each bucket in the LDM hash table for collision resolution.
426 * Larger values improve collision resolution but decrease compression speed.
427 * The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX.
428 * Special: value 0 means "use default value" (default: 3). */
429 ZSTD_c_ldmHashRateLog=164, /* Frequency of inserting/looking up entries into the LDM hash table.
430 * Must be clamped between 0 and (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN).
431 * Default is MAX(0, (windowLog - ldmHashLog)), optimizing hash table usage.
432 * Larger values improve compression speed.
433 * Deviating far from default value will likely result in a compression ratio decrease.
434 * Special: value 0 means "automatically determine hashRateLog". */
435
436 /* frame parameters */
437 ZSTD_c_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1)
438 * Content size must be known at the beginning of compression.
439 * This is automatically the case when using ZSTD_compress2(),
440 * For streaming scenarios, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */
441 ZSTD_c_checksumFlag=201, /* A 32-bits checksum of content is written at end of frame (default:0) */
442 ZSTD_c_dictIDFlag=202, /* When applicable, dictionary's ID is written into frame header (default:1) */
443
444 /* multi-threading parameters */
445 /* These parameters are only active if multi-threading is enabled (compiled with build macro ZSTD_MULTITHREAD).
446 * Otherwise, trying to set any other value than default (0) will be a no-op and return an error.
447 * In a situation where it's unknown if the linked library supports multi-threading or not,
448 * setting ZSTD_c_nbWorkers to any value >= 1 and consulting the return value provides a quick way to check this property.
449 */
450 ZSTD_c_nbWorkers=400, /* Select how many threads will be spawned to compress in parallel.
451 * When nbWorkers >= 1, triggers asynchronous mode when invoking ZSTD_compressStream*() :
452 * ZSTD_compressStream*() consumes input and flush output if possible, but immediately gives back control to caller,
453 * while compression is performed in parallel, within worker thread(s).
454 * (note : a strong exception to this rule is when first invocation of ZSTD_compressStream2() sets ZSTD_e_end :
455 * in which case, ZSTD_compressStream2() delegates to ZSTD_compress2(), which is always a blocking call).
456 * More workers improve speed, but also increase memory usage.
457 * Default value is `0`, aka "single-threaded mode" : no worker is spawned,
458 * compression is performed inside Caller's thread, and all invocations are blocking */
459 ZSTD_c_jobSize=401, /* Size of a compression job. This value is enforced only when nbWorkers >= 1.
460 * Each compression job is completed in parallel, so this value can indirectly impact the nb of active threads.
461 * 0 means default, which is dynamically determined based on compression parameters.
462 * Job size must be a minimum of overlap size, or ZSTDMT_JOBSIZE_MIN (= 512 KB), whichever is largest.
463 * The minimum size is automatically and transparently enforced. */
464 ZSTD_c_overlapLog=402, /* Control the overlap size, as a fraction of window size.
465 * The overlap size is an amount of data reloaded from previous job at the beginning of a new job.
466 * It helps preserve compression ratio, while each job is compressed in parallel.
467 * This value is enforced only when nbWorkers >= 1.
468 * Larger values increase compression ratio, but decrease speed.
469 * Possible values range from 0 to 9 :
470 * - 0 means "default" : value will be determined by the library, depending on strategy
471 * - 1 means "no overlap"
472 * - 9 means "full overlap", using a full window size.
473 * Each intermediate rank increases/decreases load size by a factor 2 :
474 * 9: full window; 8: w/2; 7: w/4; 6: w/8; 5:w/16; 4: w/32; 3:w/64; 2:w/128; 1:no overlap; 0:default
475 * default value varies between 6 and 9, depending on strategy */
476
477 /* note : additional experimental parameters are also available
478 * within the experimental section of the API.
479 * At the time of this writing, they include :
480 * ZSTD_c_rsyncable
481 * ZSTD_c_format
482 * ZSTD_c_forceMaxWindow
483 * ZSTD_c_forceAttachDict
484 * ZSTD_c_literalCompressionMode
648db22b 485 * ZSTD_c_srcSizeHint
486 * ZSTD_c_enableDedicatedDictSearch
487 * ZSTD_c_stableInBuffer
488 * ZSTD_c_stableOutBuffer
489 * ZSTD_c_blockDelimiters
490 * ZSTD_c_validateSequences
491 * ZSTD_c_useBlockSplitter
492 * ZSTD_c_useRowMatchFinder
493 * ZSTD_c_prefetchCDictTables
494 * ZSTD_c_enableSeqProducerFallback
495 * ZSTD_c_maxBlockSize
496 * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
497 * note : never ever use experimentalParam? names directly;
498 * also, the enums values themselves are unstable and can still change.
499 */
500 ZSTD_c_experimentalParam1=500,
501 ZSTD_c_experimentalParam2=10,
502 ZSTD_c_experimentalParam3=1000,
503 ZSTD_c_experimentalParam4=1001,
504 ZSTD_c_experimentalParam5=1002,
f535537f 505 /* was ZSTD_c_experimentalParam6=1003; is now ZSTD_c_targetCBlockSize */
648db22b 506 ZSTD_c_experimentalParam7=1004,
507 ZSTD_c_experimentalParam8=1005,
508 ZSTD_c_experimentalParam9=1006,
509 ZSTD_c_experimentalParam10=1007,
510 ZSTD_c_experimentalParam11=1008,
511 ZSTD_c_experimentalParam12=1009,
512 ZSTD_c_experimentalParam13=1010,
513 ZSTD_c_experimentalParam14=1011,
514 ZSTD_c_experimentalParam15=1012,
515 ZSTD_c_experimentalParam16=1013,
516 ZSTD_c_experimentalParam17=1014,
517 ZSTD_c_experimentalParam18=1015,
518 ZSTD_c_experimentalParam19=1016
519} ZSTD_cParameter;
520
521typedef struct {
522 size_t error;
523 int lowerBound;
524 int upperBound;
525} ZSTD_bounds;
526
527/*! ZSTD_cParam_getBounds() :
528 * All parameters must belong to an interval with lower and upper bounds,
529 * otherwise they will either trigger an error or be automatically clamped.
530 * @return : a structure, ZSTD_bounds, which contains
531 * - an error status field, which must be tested using ZSTD_isError()
532 * - lower and upper bounds, both inclusive
533 */
534ZSTDLIB_API ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter cParam);
535
536/*! ZSTD_CCtx_setParameter() :
537 * Set one compression parameter, selected by enum ZSTD_cParameter.
538 * All parameters have valid bounds. Bounds can be queried using ZSTD_cParam_getBounds().
539 * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter).
540 * Setting a parameter is generally only possible during frame initialization (before starting compression).
541 * Exception : when using multi-threading mode (nbWorkers >= 1),
542 * the following parameters can be updated _during_ compression (within same frame):
543 * => compressionLevel, hashLog, chainLog, searchLog, minMatch, targetLength and strategy.
544 * new parameters will be active for next job only (after a flush()).
545 * @return : an error code (which can be tested using ZSTD_isError()).
546 */
547ZSTDLIB_API size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value);
548
549/*! ZSTD_CCtx_setPledgedSrcSize() :
550 * Total input data size to be compressed as a single frame.
551 * Value will be written in frame header, unless if explicitly forbidden using ZSTD_c_contentSizeFlag.
552 * This value will also be controlled at end of frame, and trigger an error if not respected.
553 * @result : 0, or an error code (which can be tested with ZSTD_isError()).
554 * Note 1 : pledgedSrcSize==0 actually means zero, aka an empty frame.
555 * In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN.
556 * ZSTD_CONTENTSIZE_UNKNOWN is default value for any new frame.
557 * Note 2 : pledgedSrcSize is only valid once, for the next frame.
558 * It's discarded at the end of the frame, and replaced by ZSTD_CONTENTSIZE_UNKNOWN.
559 * Note 3 : Whenever all input data is provided and consumed in a single round,
560 * for example with ZSTD_compress2(),
561 * or invoking immediately ZSTD_compressStream2(,,,ZSTD_e_end),
562 * this value is automatically overridden by srcSize instead.
563 */
564ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize);
565
566typedef enum {
567 ZSTD_reset_session_only = 1,
568 ZSTD_reset_parameters = 2,
569 ZSTD_reset_session_and_parameters = 3
570} ZSTD_ResetDirective;
571
572/*! ZSTD_CCtx_reset() :
573 * There are 2 different things that can be reset, independently or jointly :
574 * - The session : will stop compressing current frame, and make CCtx ready to start a new one.
575 * Useful after an error, or to interrupt any ongoing compression.
576 * Any internal data not yet flushed is cancelled.
577 * Compression parameters and dictionary remain unchanged.
578 * They will be used to compress next frame.
579 * Resetting session never fails.
580 * - The parameters : changes all parameters back to "default".
581 * This also removes any reference to any dictionary or external sequence producer.
582 * Parameters can only be changed between 2 sessions (i.e. no compression is currently ongoing)
583 * otherwise the reset fails, and function returns an error value (which can be tested using ZSTD_isError())
584 * - Both : similar to resetting the session, followed by resetting parameters.
585 */
586ZSTDLIB_API size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset);
587
588/*! ZSTD_compress2() :
589 * Behave the same as ZSTD_compressCCtx(), but compression parameters are set using the advanced API.
f535537f 590 * (note that this entry point doesn't even expose a compression level parameter).
648db22b 591 * ZSTD_compress2() always starts a new frame.
592 * Should cctx hold data from a previously unfinished frame, everything about it is forgotten.
593 * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*()
594 * - The function is always blocking, returns when compression is completed.
595 * NOTE: Providing `dstCapacity >= ZSTD_compressBound(srcSize)` guarantees that zstd will have
596 * enough space to successfully compress the data, though it is possible it fails for other reasons.
597 * @return : compressed size written into `dst` (<= `dstCapacity),
598 * or an error code if it fails (which can be tested using ZSTD_isError()).
599 */
600ZSTDLIB_API size_t ZSTD_compress2( ZSTD_CCtx* cctx,
601 void* dst, size_t dstCapacity,
602 const void* src, size_t srcSize);
603
604
605/***********************************************
606* Advanced decompression API (Requires v1.4.0+)
607************************************************/
608
609/* The advanced API pushes parameters one by one into an existing DCtx context.
610 * Parameters are sticky, and remain valid for all following frames
611 * using the same DCtx context.
612 * It's possible to reset parameters to default values using ZSTD_DCtx_reset().
613 * Note : This API is compatible with existing ZSTD_decompressDCtx() and ZSTD_decompressStream().
614 * Therefore, no new decompression function is necessary.
615 */
616
617typedef enum {
618
619 ZSTD_d_windowLogMax=100, /* Select a size limit (in power of 2) beyond which
620 * the streaming API will refuse to allocate memory buffer
621 * in order to protect the host from unreasonable memory requirements.
622 * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode.
623 * By default, a decompression context accepts window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT).
624 * Special: value 0 means "use default maximum windowLog". */
625
626 /* note : additional experimental parameters are also available
627 * within the experimental section of the API.
628 * At the time of this writing, they include :
629 * ZSTD_d_format
630 * ZSTD_d_stableOutBuffer
631 * ZSTD_d_forceIgnoreChecksum
632 * ZSTD_d_refMultipleDDicts
633 * ZSTD_d_disableHuffmanAssembly
f535537f 634 * ZSTD_d_maxBlockSize
648db22b 635 * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
636 * note : never ever use experimentalParam? names directly
637 */
638 ZSTD_d_experimentalParam1=1000,
639 ZSTD_d_experimentalParam2=1001,
640 ZSTD_d_experimentalParam3=1002,
641 ZSTD_d_experimentalParam4=1003,
f535537f 642 ZSTD_d_experimentalParam5=1004,
643 ZSTD_d_experimentalParam6=1005
648db22b 644
645} ZSTD_dParameter;
646
647/*! ZSTD_dParam_getBounds() :
648 * All parameters must belong to an interval with lower and upper bounds,
649 * otherwise they will either trigger an error or be automatically clamped.
650 * @return : a structure, ZSTD_bounds, which contains
651 * - an error status field, which must be tested using ZSTD_isError()
652 * - both lower and upper bounds, inclusive
653 */
654ZSTDLIB_API ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam);
655
656/*! ZSTD_DCtx_setParameter() :
657 * Set one compression parameter, selected by enum ZSTD_dParameter.
658 * All parameters have valid bounds. Bounds can be queried using ZSTD_dParam_getBounds().
659 * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter).
660 * Setting a parameter is only possible during frame initialization (before starting decompression).
661 * @return : 0, or an error code (which can be tested using ZSTD_isError()).
662 */
663ZSTDLIB_API size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int value);
664
665/*! ZSTD_DCtx_reset() :
666 * Return a DCtx to clean state.
667 * Session and parameters can be reset jointly or separately.
668 * Parameters can only be reset when no active frame is being decompressed.
669 * @return : 0, or an error code, which can be tested with ZSTD_isError()
670 */
671ZSTDLIB_API size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset);
672
673
674/****************************
675* Streaming
676****************************/
677
678typedef struct ZSTD_inBuffer_s {
679 const void* src; /**< start of input buffer */
680 size_t size; /**< size of input buffer */
681 size_t pos; /**< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */
682} ZSTD_inBuffer;
683
684typedef struct ZSTD_outBuffer_s {
685 void* dst; /**< start of output buffer */
686 size_t size; /**< size of output buffer */
687 size_t pos; /**< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */
688} ZSTD_outBuffer;
689
690
691
692/*-***********************************************************************
693* Streaming compression - HowTo
694*
695* A ZSTD_CStream object is required to track streaming operation.
696* Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources.
697* ZSTD_CStream objects can be reused multiple times on consecutive compression operations.
f535537f 698* It is recommended to reuse ZSTD_CStream since it will play nicer with system's memory, by re-using already allocated memory.
648db22b 699*
700* For parallel execution, use one separate ZSTD_CStream per thread.
701*
702* note : since v1.3.0, ZSTD_CStream and ZSTD_CCtx are the same thing.
703*
704* Parameters are sticky : when starting a new compression on the same context,
f535537f 705* it will reuse the same sticky parameters as previous compression session.
648db22b 706* When in doubt, it's recommended to fully initialize the context before usage.
707* Use ZSTD_CCtx_reset() to reset the context and ZSTD_CCtx_setParameter(),
708* ZSTD_CCtx_setPledgedSrcSize(), or ZSTD_CCtx_loadDictionary() and friends to
709* set more specific parameters, the pledged source size, or load a dictionary.
710*
711* Use ZSTD_compressStream2() with ZSTD_e_continue as many times as necessary to
712* consume input stream. The function will automatically update both `pos`
713* fields within `input` and `output`.
714* Note that the function may not consume the entire input, for example, because
715* the output buffer is already full, in which case `input.pos < input.size`.
716* The caller must check if input has been entirely consumed.
717* If not, the caller must make some room to receive more compressed data,
718* and then present again remaining input data.
719* note: ZSTD_e_continue is guaranteed to make some forward progress when called,
720* but doesn't guarantee maximal forward progress. This is especially relevant
721* when compressing with multiple threads. The call won't block if it can
722* consume some input, but if it can't it will wait for some, but not all,
723* output to be flushed.
724* @return : provides a minimum amount of data remaining to be flushed from internal buffers
725* or an error code, which can be tested using ZSTD_isError().
726*
727* At any moment, it's possible to flush whatever data might remain stuck within internal buffer,
728* using ZSTD_compressStream2() with ZSTD_e_flush. `output->pos` will be updated.
729* Note that, if `output->size` is too small, a single invocation with ZSTD_e_flush might not be enough (return code > 0).
730* In which case, make some room to receive more compressed data, and call again ZSTD_compressStream2() with ZSTD_e_flush.
731* You must continue calling ZSTD_compressStream2() with ZSTD_e_flush until it returns 0, at which point you can change the
732* operation.
733* note: ZSTD_e_flush will flush as much output as possible, meaning when compressing with multiple threads, it will
734* block until the flush is complete or the output buffer is full.
735* @return : 0 if internal buffers are entirely flushed,
736* >0 if some data still present within internal buffer (the value is minimal estimation of remaining size),
737* or an error code, which can be tested using ZSTD_isError().
738*
739* Calling ZSTD_compressStream2() with ZSTD_e_end instructs to finish a frame.
740* It will perform a flush and write frame epilogue.
741* The epilogue is required for decoders to consider a frame completed.
742* flush operation is the same, and follows same rules as calling ZSTD_compressStream2() with ZSTD_e_flush.
743* You must continue calling ZSTD_compressStream2() with ZSTD_e_end until it returns 0, at which point you are free to
744* start a new frame.
745* note: ZSTD_e_end will flush as much output as possible, meaning when compressing with multiple threads, it will
746* block until the flush is complete or the output buffer is full.
747* @return : 0 if frame fully completed and fully flushed,
748* >0 if some data still present within internal buffer (the value is minimal estimation of remaining size),
749* or an error code, which can be tested using ZSTD_isError().
750*
751* *******************************************************************/
752
753typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are now effectively same object (>= v1.3.0) */
754 /* Continue to distinguish them for compatibility with older versions <= v1.2.0 */
755/*===== ZSTD_CStream management functions =====*/
756ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void);
757ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs); /* accept NULL pointer */
758
759/*===== Streaming compression functions =====*/
760typedef enum {
761 ZSTD_e_continue=0, /* collect more data, encoder decides when to output compressed result, for optimal compression ratio */
762 ZSTD_e_flush=1, /* flush any data provided so far,
763 * it creates (at least) one new block, that can be decoded immediately on reception;
764 * frame will continue: any future data can still reference previously compressed data, improving compression.
765 * note : multithreaded compression will block to flush as much output as possible. */
766 ZSTD_e_end=2 /* flush any remaining data _and_ close current frame.
767 * note that frame is only closed after compressed data is fully flushed (return value == 0).
768 * After that point, any additional data starts a new frame.
769 * note : each frame is independent (does not reference any content from previous frame).
770 : note : multithreaded compression will block to flush as much output as possible. */
771} ZSTD_EndDirective;
772
773/*! ZSTD_compressStream2() : Requires v1.4.0+
774 * Behaves about the same as ZSTD_compressStream, with additional control on end directive.
775 * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*()
776 * - Compression parameters cannot be changed once compression is started (save a list of exceptions in multi-threading mode)
777 * - output->pos must be <= dstCapacity, input->pos must be <= srcSize
778 * - output->pos and input->pos will be updated. They are guaranteed to remain below their respective limit.
779 * - endOp must be a valid directive
780 * - When nbWorkers==0 (default), function is blocking : it completes its job before returning to caller.
781 * - When nbWorkers>=1, function is non-blocking : it copies a portion of input, distributes jobs to internal worker threads, flush to output whatever is available,
782 * and then immediately returns, just indicating that there is some data remaining to be flushed.
783 * The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte.
784 * - Exception : if the first call requests a ZSTD_e_end directive and provides enough dstCapacity, the function delegates to ZSTD_compress2() which is always blocking.
785 * - @return provides a minimum amount of data remaining to be flushed from internal buffers
786 * or an error code, which can be tested using ZSTD_isError().
787 * if @return != 0, flush is not fully completed, there is still some data left within internal buffers.
788 * This is useful for ZSTD_e_flush, since in this case more flushes are necessary to empty all buffers.
789 * For ZSTD_e_end, @return == 0 when internal buffers are fully flushed and frame is completed.
790 * - after a ZSTD_e_end directive, if internal buffer is not fully flushed (@return != 0),
791 * only ZSTD_e_end or ZSTD_e_flush operations are allowed.
792 * Before starting a new compression job, or changing compression parameters,
793 * it is required to fully flush internal buffers.
f535537f 794 * - note: if an operation ends with an error, it may leave @cctx in an undefined state.
795 * Therefore, it's UB to invoke ZSTD_compressStream2() of ZSTD_compressStream() on such a state.
796 * In order to be re-employed after an error, a state must be reset,
797 * which can be done explicitly (ZSTD_CCtx_reset()),
798 * or is sometimes implied by methods starting a new compression job (ZSTD_initCStream(), ZSTD_compressCCtx())
648db22b 799 */
800ZSTDLIB_API size_t ZSTD_compressStream2( ZSTD_CCtx* cctx,
801 ZSTD_outBuffer* output,
802 ZSTD_inBuffer* input,
803 ZSTD_EndDirective endOp);
804
805
806/* These buffer sizes are softly recommended.
807 * They are not required : ZSTD_compressStream*() happily accepts any buffer size, for both input and output.
808 * Respecting the recommended size just makes it a bit easier for ZSTD_compressStream*(),
809 * reducing the amount of memory shuffling and buffering, resulting in minor performance savings.
810 *
811 * However, note that these recommendations are from the perspective of a C caller program.
812 * If the streaming interface is invoked from some other language,
813 * especially managed ones such as Java or Go, through a foreign function interface such as jni or cgo,
814 * a major performance rule is to reduce crossing such interface to an absolute minimum.
815 * It's not rare that performance ends being spent more into the interface, rather than compression itself.
816 * In which cases, prefer using large buffers, as large as practical,
817 * for both input and output, to reduce the nb of roundtrips.
818 */
819ZSTDLIB_API size_t ZSTD_CStreamInSize(void); /**< recommended size for input buffer */
820ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block. */
821
822
823/* *****************************************************************************
824 * This following is a legacy streaming API, available since v1.0+ .
825 * It can be replaced by ZSTD_CCtx_reset() and ZSTD_compressStream2().
826 * It is redundant, but remains fully supported.
827 ******************************************************************************/
828
829/*!
830 * Equivalent to:
831 *
832 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
833 * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any)
834 * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
835 *
836 * Note that ZSTD_initCStream() clears any previously set dictionary. Use the new API
837 * to compress with a dictionary.
838 */
839ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel);
840/*!
841 * Alternative for ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue).
842 * NOTE: The return value is different. ZSTD_compressStream() returns a hint for
843 * the next read size (if non-zero and not an error). ZSTD_compressStream2()
844 * returns the minimum nb of bytes left to flush (if non-zero and not an error).
845 */
846ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
847/*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_flush). */
848ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output);
849/*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_end). */
850ZSTDLIB_API size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output);
851
852
853/*-***************************************************************************
854* Streaming decompression - HowTo
855*
856* A ZSTD_DStream object is required to track streaming operations.
857* Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources.
f535537f 858* ZSTD_DStream objects can be reused multiple times.
648db22b 859*
860* Use ZSTD_initDStream() to start a new decompression operation.
861* @return : recommended first input size
862* Alternatively, use advanced API to set specific properties.
863*
864* Use ZSTD_decompressStream() repetitively to consume your input.
865* The function will update both `pos` fields.
866* If `input.pos < input.size`, some input has not been consumed.
867* It's up to the caller to present again remaining data.
868* The function tries to flush all data decoded immediately, respecting output buffer size.
869* If `output.pos < output.size`, decoder has flushed everything it could.
870* But if `output.pos == output.size`, there might be some data left within internal buffers.,
871* In which case, call ZSTD_decompressStream() again to flush whatever remains in the buffer.
872* Note : with no additional input provided, amount of data flushed is necessarily <= ZSTD_BLOCKSIZE_MAX.
873* @return : 0 when a frame is completely decoded and fully flushed,
874* or an error code, which can be tested using ZSTD_isError(),
875* or any other value > 0, which means there is still some decoding or flushing to do to complete current frame :
876* the return value is a suggested next input size (just a hint for better latency)
877* that will never request more than the remaining frame size.
878* *******************************************************************************/
879
880typedef ZSTD_DCtx ZSTD_DStream; /**< DCtx and DStream are now effectively same object (>= v1.3.0) */
881 /* For compatibility with versions <= v1.2.0, prefer differentiating them. */
882/*===== ZSTD_DStream management functions =====*/
883ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void);
884ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds); /* accept NULL pointer */
885
886/*===== Streaming decompression functions =====*/
887
888/*! ZSTD_initDStream() :
889 * Initialize/reset DStream state for new decompression operation.
890 * Call before new decompression operation using same DStream.
891 *
892 * Note : This function is redundant with the advanced API and equivalent to:
893 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
894 * ZSTD_DCtx_refDDict(zds, NULL);
895 */
896ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds);
897
898/*! ZSTD_decompressStream() :
899 * Streaming decompression function.
900 * Call repetitively to consume full input updating it as necessary.
901 * Function will update both input and output `pos` fields exposing current state via these fields:
902 * - `input.pos < input.size`, some input remaining and caller should provide remaining input
903 * on the next call.
904 * - `output.pos < output.size`, decoder finished and flushed all remaining buffers.
905 * - `output.pos == output.size`, potentially uncflushed data present in the internal buffers,
906 * call ZSTD_decompressStream() again to flush remaining data to output.
907 * Note : with no additional input, amount of data flushed <= ZSTD_BLOCKSIZE_MAX.
908 *
909 * @return : 0 when a frame is completely decoded and fully flushed,
910 * or an error code, which can be tested using ZSTD_isError(),
911 * or any other value > 0, which means there is some decoding or flushing to do to complete current frame.
f535537f 912 *
913 * Note: when an operation returns with an error code, the @zds state may be left in undefined state.
914 * It's UB to invoke `ZSTD_decompressStream()` on such a state.
915 * In order to re-use such a state, it must be first reset,
916 * which can be done explicitly (`ZSTD_DCtx_reset()`),
917 * or is implied for operations starting some new decompression job (`ZSTD_initDStream`, `ZSTD_decompressDCtx()`, `ZSTD_decompress_usingDict()`)
648db22b 918 */
919ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
920
921ZSTDLIB_API size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */
922ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */
923
924
925/**************************
926* Simple dictionary API
927***************************/
928/*! ZSTD_compress_usingDict() :
929 * Compression at an explicit compression level using a Dictionary.
930 * A dictionary can be any arbitrary data segment (also called a prefix),
931 * or a buffer with specified information (see zdict.h).
932 * Note : This function loads the dictionary, resulting in significant startup delay.
933 * It's intended for a dictionary used only once.
934 * Note 2 : When `dict == NULL || dictSize < 8` no dictionary is used. */
935ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
936 void* dst, size_t dstCapacity,
937 const void* src, size_t srcSize,
938 const void* dict,size_t dictSize,
939 int compressionLevel);
940
941/*! ZSTD_decompress_usingDict() :
942 * Decompression using a known Dictionary.
943 * Dictionary must be identical to the one used during compression.
944 * Note : This function loads the dictionary, resulting in significant startup delay.
945 * It's intended for a dictionary used only once.
946 * Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
947ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
948 void* dst, size_t dstCapacity,
949 const void* src, size_t srcSize,
950 const void* dict,size_t dictSize);
951
952
953/***********************************
954 * Bulk processing dictionary API
955 **********************************/
956typedef struct ZSTD_CDict_s ZSTD_CDict;
957
958/*! ZSTD_createCDict() :
959 * When compressing multiple messages or blocks using the same dictionary,
960 * it's recommended to digest the dictionary only once, since it's a costly operation.
961 * ZSTD_createCDict() will create a state from digesting a dictionary.
962 * The resulting state can be used for future compression operations with very limited startup cost.
963 * ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only.
964 * @dictBuffer can be released after ZSTD_CDict creation, because its content is copied within CDict.
965 * Note 1 : Consider experimental function `ZSTD_createCDict_byReference()` if you prefer to not duplicate @dictBuffer content.
966 * Note 2 : A ZSTD_CDict can be created from an empty @dictBuffer,
967 * in which case the only thing that it transports is the @compressionLevel.
968 * This can be useful in a pipeline featuring ZSTD_compress_usingCDict() exclusively,
969 * expecting a ZSTD_CDict parameter with any data, including those without a known dictionary. */
970ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize,
971 int compressionLevel);
972
973/*! ZSTD_freeCDict() :
974 * Function frees memory allocated by ZSTD_createCDict().
975 * If a NULL pointer is passed, no operation is performed. */
976ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict);
977
978/*! ZSTD_compress_usingCDict() :
979 * Compression using a digested Dictionary.
980 * Recommended when same dictionary is used multiple times.
981 * Note : compression level is _decided at dictionary creation time_,
982 * and frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) */
983ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
984 void* dst, size_t dstCapacity,
985 const void* src, size_t srcSize,
986 const ZSTD_CDict* cdict);
987
988
989typedef struct ZSTD_DDict_s ZSTD_DDict;
990
991/*! ZSTD_createDDict() :
992 * Create a digested dictionary, ready to start decompression operation without startup delay.
993 * dictBuffer can be released after DDict creation, as its content is copied inside DDict. */
994ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize);
995
996/*! ZSTD_freeDDict() :
997 * Function frees memory allocated with ZSTD_createDDict()
998 * If a NULL pointer is passed, no operation is performed. */
999ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict);
1000
1001/*! ZSTD_decompress_usingDDict() :
1002 * Decompression using a digested Dictionary.
1003 * Recommended when same dictionary is used multiple times. */
1004ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
1005 void* dst, size_t dstCapacity,
1006 const void* src, size_t srcSize,
1007 const ZSTD_DDict* ddict);
1008
1009
1010/********************************
1011 * Dictionary helper functions
1012 *******************************/
1013
1014/*! ZSTD_getDictID_fromDict() : Requires v1.4.0+
1015 * Provides the dictID stored within dictionary.
1016 * if @return == 0, the dictionary is not conformant with Zstandard specification.
1017 * It can still be loaded, but as a content-only dictionary. */
1018ZSTDLIB_API unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize);
1019
1020/*! ZSTD_getDictID_fromCDict() : Requires v1.5.0+
1021 * Provides the dictID of the dictionary loaded into `cdict`.
1022 * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
1023 * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
1024ZSTDLIB_API unsigned ZSTD_getDictID_fromCDict(const ZSTD_CDict* cdict);
1025
1026/*! ZSTD_getDictID_fromDDict() : Requires v1.4.0+
1027 * Provides the dictID of the dictionary loaded into `ddict`.
1028 * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
1029 * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
1030ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict);
1031
1032/*! ZSTD_getDictID_fromFrame() : Requires v1.4.0+
1033 * Provides the dictID required to decompressed the frame stored within `src`.
1034 * If @return == 0, the dictID could not be decoded.
1035 * This could for one of the following reasons :
1036 * - The frame does not require a dictionary to be decoded (most common case).
1037 * - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden piece of information.
1038 * Note : this use case also happens when using a non-conformant dictionary.
1039 * - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`).
1040 * - This is not a Zstandard frame.
1041 * When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. */
1042ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize);
1043
1044
1045/*******************************************************************************
1046 * Advanced dictionary and prefix API (Requires v1.4.0+)
1047 *
1048 * This API allows dictionaries to be used with ZSTD_compress2(),
1049 * ZSTD_compressStream2(), and ZSTD_decompressDCtx().
f535537f 1050 * Dictionaries are sticky, they remain valid when same context is reused,
648db22b 1051 * they only reset when the context is reset
1052 * with ZSTD_reset_parameters or ZSTD_reset_session_and_parameters.
1053 * In contrast, Prefixes are single-use.
1054 ******************************************************************************/
1055
1056
1057/*! ZSTD_CCtx_loadDictionary() : Requires v1.4.0+
1058 * Create an internal CDict from `dict` buffer.
1059 * Decompression will have to use same dictionary.
1060 * @result : 0, or an error code (which can be tested with ZSTD_isError()).
1061 * Special: Loading a NULL (or 0-size) dictionary invalidates previous dictionary,
1062 * meaning "return to no-dictionary mode".
1063 * Note 1 : Dictionary is sticky, it will be used for all future compressed frames,
1064 * until parameters are reset, a new dictionary is loaded, or the dictionary
1065 * is explicitly invalidated by loading a NULL dictionary.
1066 * Note 2 : Loading a dictionary involves building tables.
1067 * It's also a CPU consuming operation, with non-negligible impact on latency.
1068 * Tables are dependent on compression parameters, and for this reason,
1069 * compression parameters can no longer be changed after loading a dictionary.
1070 * Note 3 :`dict` content will be copied internally.
1071 * Use experimental ZSTD_CCtx_loadDictionary_byReference() to reference content instead.
1072 * In such a case, dictionary buffer must outlive its users.
1073 * Note 4 : Use ZSTD_CCtx_loadDictionary_advanced()
1074 * to precisely select how dictionary content must be interpreted.
1075 * Note 5 : This method does not benefit from LDM (long distance mode).
1076 * If you want to employ LDM on some large dictionary content,
1077 * prefer employing ZSTD_CCtx_refPrefix() described below.
1078 */
1079ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
1080
1081/*! ZSTD_CCtx_refCDict() : Requires v1.4.0+
1082 * Reference a prepared dictionary, to be used for all future compressed frames.
1083 * Note that compression parameters are enforced from within CDict,
1084 * and supersede any compression parameter previously set within CCtx.
1085 * The parameters ignored are labelled as "superseded-by-cdict" in the ZSTD_cParameter enum docs.
1086 * The ignored parameters will be used again if the CCtx is returned to no-dictionary mode.
1087 * The dictionary will remain valid for future compressed frames using same CCtx.
1088 * @result : 0, or an error code (which can be tested with ZSTD_isError()).
1089 * Special : Referencing a NULL CDict means "return to no-dictionary mode".
1090 * Note 1 : Currently, only one dictionary can be managed.
1091 * Referencing a new dictionary effectively "discards" any previous one.
1092 * Note 2 : CDict is just referenced, its lifetime must outlive its usage within CCtx. */
1093ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict);
1094
1095/*! ZSTD_CCtx_refPrefix() : Requires v1.4.0+
1096 * Reference a prefix (single-usage dictionary) for next compressed frame.
1097 * A prefix is **only used once**. Tables are discarded at end of frame (ZSTD_e_end).
1098 * Decompression will need same prefix to properly regenerate data.
1099 * Compressing with a prefix is similar in outcome as performing a diff and compressing it,
1100 * but performs much faster, especially during decompression (compression speed is tunable with compression level).
1101 * This method is compatible with LDM (long distance mode).
1102 * @result : 0, or an error code (which can be tested with ZSTD_isError()).
1103 * Special: Adding any prefix (including NULL) invalidates any previous prefix or dictionary
1104 * Note 1 : Prefix buffer is referenced. It **must** outlive compression.
1105 * Its content must remain unmodified during compression.
1106 * Note 2 : If the intention is to diff some large src data blob with some prior version of itself,
1107 * ensure that the window size is large enough to contain the entire source.
1108 * See ZSTD_c_windowLog.
1109 * Note 3 : Referencing a prefix involves building tables, which are dependent on compression parameters.
1110 * It's a CPU consuming operation, with non-negligible impact on latency.
1111 * If there is a need to use the same prefix multiple times, consider loadDictionary instead.
1112 * Note 4 : By default, the prefix is interpreted as raw content (ZSTD_dct_rawContent).
1113 * Use experimental ZSTD_CCtx_refPrefix_advanced() to alter dictionary interpretation. */
1114ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx,
1115 const void* prefix, size_t prefixSize);
1116
1117/*! ZSTD_DCtx_loadDictionary() : Requires v1.4.0+
1118 * Create an internal DDict from dict buffer, to be used to decompress all future frames.
1119 * The dictionary remains valid for all future frames, until explicitly invalidated, or
1120 * a new dictionary is loaded.
1121 * @result : 0, or an error code (which can be tested with ZSTD_isError()).
1122 * Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary,
1123 * meaning "return to no-dictionary mode".
1124 * Note 1 : Loading a dictionary involves building tables,
1125 * which has a non-negligible impact on CPU usage and latency.
1126 * It's recommended to "load once, use many times", to amortize the cost
1127 * Note 2 :`dict` content will be copied internally, so `dict` can be released after loading.
1128 * Use ZSTD_DCtx_loadDictionary_byReference() to reference dictionary content instead.
1129 * Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to take control of
1130 * how dictionary content is loaded and interpreted.
1131 */
1132ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
1133
1134/*! ZSTD_DCtx_refDDict() : Requires v1.4.0+
1135 * Reference a prepared dictionary, to be used to decompress next frames.
1136 * The dictionary remains active for decompression of future frames using same DCtx.
1137 *
1138 * If called with ZSTD_d_refMultipleDDicts enabled, repeated calls of this function
1139 * will store the DDict references in a table, and the DDict used for decompression
1140 * will be determined at decompression time, as per the dict ID in the frame.
1141 * The memory for the table is allocated on the first call to refDDict, and can be
1142 * freed with ZSTD_freeDCtx().
1143 *
1144 * If called with ZSTD_d_refMultipleDDicts disabled (the default), only one dictionary
1145 * will be managed, and referencing a dictionary effectively "discards" any previous one.
1146 *
1147 * @result : 0, or an error code (which can be tested with ZSTD_isError()).
1148 * Special: referencing a NULL DDict means "return to no-dictionary mode".
1149 * Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx.
1150 */
1151ZSTDLIB_API size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict);
1152
1153/*! ZSTD_DCtx_refPrefix() : Requires v1.4.0+
1154 * Reference a prefix (single-usage dictionary) to decompress next frame.
1155 * This is the reverse operation of ZSTD_CCtx_refPrefix(),
1156 * and must use the same prefix as the one used during compression.
1157 * Prefix is **only used once**. Reference is discarded at end of frame.
1158 * End of frame is reached when ZSTD_decompressStream() returns 0.
1159 * @result : 0, or an error code (which can be tested with ZSTD_isError()).
1160 * Note 1 : Adding any prefix (including NULL) invalidates any previously set prefix or dictionary
1161 * Note 2 : Prefix buffer is referenced. It **must** outlive decompression.
1162 * Prefix buffer must remain unmodified up to the end of frame,
1163 * reached when ZSTD_decompressStream() returns 0.
1164 * Note 3 : By default, the prefix is treated as raw content (ZSTD_dct_rawContent).
1165 * Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode (Experimental section)
1166 * Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost.
1167 * A full dictionary is more costly, as it requires building tables.
1168 */
1169ZSTDLIB_API size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx,
1170 const void* prefix, size_t prefixSize);
1171
1172/* === Memory management === */
1173
1174/*! ZSTD_sizeof_*() : Requires v1.4.0+
1175 * These functions give the _current_ memory usage of selected object.
1176 * Note that object memory usage can evolve (increase or decrease) over time. */
1177ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);
1178ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx);
1179ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs);
1180ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds);
1181ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict);
1182ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
1183
1184#endif /* ZSTD_H_235446 */
1185
1186
1187/* **************************************************************************************
1188 * ADVANCED AND EXPERIMENTAL FUNCTIONS
1189 ****************************************************************************************
1190 * The definitions in the following section are considered experimental.
1191 * They are provided for advanced scenarios.
1192 * They should never be used with a dynamic library, as prototypes may change in the future.
1193 * Use them only in association with static linking.
1194 * ***************************************************************************************/
1195
1196#if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY)
1197#define ZSTD_H_ZSTD_STATIC_LINKING_ONLY
1198
1199/* This can be overridden externally to hide static symbols. */
1200#ifndef ZSTDLIB_STATIC_API
1201# if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
1202# define ZSTDLIB_STATIC_API __declspec(dllexport) ZSTDLIB_VISIBLE
1203# elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1)
1204# define ZSTDLIB_STATIC_API __declspec(dllimport) ZSTDLIB_VISIBLE
1205# else
1206# define ZSTDLIB_STATIC_API ZSTDLIB_VISIBLE
1207# endif
1208#endif
1209
1210/****************************************************************************************
1211 * experimental API (static linking only)
1212 ****************************************************************************************
1213 * The following symbols and constants
1214 * are not planned to join "stable API" status in the near future.
1215 * They can still change in future versions.
1216 * Some of them are planned to remain in the static_only section indefinitely.
1217 * Some of them might be removed in the future (especially when redundant with existing stable functions)
1218 * ***************************************************************************************/
1219
1220#define ZSTD_FRAMEHEADERSIZE_PREFIX(format) ((format) == ZSTD_f_zstd1 ? 5 : 1) /* minimum input size required to query frame header size */
1221#define ZSTD_FRAMEHEADERSIZE_MIN(format) ((format) == ZSTD_f_zstd1 ? 6 : 2)
1222#define ZSTD_FRAMEHEADERSIZE_MAX 18 /* can be useful for static allocation */
1223#define ZSTD_SKIPPABLEHEADERSIZE 8
1224
1225/* compression parameter bounds */
1226#define ZSTD_WINDOWLOG_MAX_32 30
1227#define ZSTD_WINDOWLOG_MAX_64 31
1228#define ZSTD_WINDOWLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64))
1229#define ZSTD_WINDOWLOG_MIN 10
1230#define ZSTD_HASHLOG_MAX ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30)
1231#define ZSTD_HASHLOG_MIN 6
1232#define ZSTD_CHAINLOG_MAX_32 29
1233#define ZSTD_CHAINLOG_MAX_64 30
1234#define ZSTD_CHAINLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64))
1235#define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN
1236#define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1)
1237#define ZSTD_SEARCHLOG_MIN 1
1238#define ZSTD_MINMATCH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */
1239#define ZSTD_MINMATCH_MIN 3 /* only for ZSTD_btopt+, faster strategies are limited to 4 */
1240#define ZSTD_TARGETLENGTH_MAX ZSTD_BLOCKSIZE_MAX
1241#define ZSTD_TARGETLENGTH_MIN 0 /* note : comparing this constant to an unsigned results in a tautological test */
1242#define ZSTD_STRATEGY_MIN ZSTD_fast
1243#define ZSTD_STRATEGY_MAX ZSTD_btultra2
1244#define ZSTD_BLOCKSIZE_MAX_MIN (1 << 10) /* The minimum valid max blocksize. Maximum blocksizes smaller than this make compressBound() inaccurate. */
1245
1246
1247#define ZSTD_OVERLAPLOG_MIN 0
1248#define ZSTD_OVERLAPLOG_MAX 9
1249
1250#define ZSTD_WINDOWLOG_LIMIT_DEFAULT 27 /* by default, the streaming decoder will refuse any frame
1251 * requiring larger than (1<<ZSTD_WINDOWLOG_LIMIT_DEFAULT) window size,
1252 * to preserve host's memory from unreasonable requirements.
1253 * This limit can be overridden using ZSTD_DCtx_setParameter(,ZSTD_d_windowLogMax,).
1254 * The limit does not apply for one-pass decoders (such as ZSTD_decompress()), since no additional memory is allocated */
1255
1256
1257/* LDM parameter bounds */
1258#define ZSTD_LDM_HASHLOG_MIN ZSTD_HASHLOG_MIN
1259#define ZSTD_LDM_HASHLOG_MAX ZSTD_HASHLOG_MAX
1260#define ZSTD_LDM_MINMATCH_MIN 4
1261#define ZSTD_LDM_MINMATCH_MAX 4096
1262#define ZSTD_LDM_BUCKETSIZELOG_MIN 1
1263#define ZSTD_LDM_BUCKETSIZELOG_MAX 8
1264#define ZSTD_LDM_HASHRATELOG_MIN 0
1265#define ZSTD_LDM_HASHRATELOG_MAX (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN)
1266
1267/* Advanced parameter bounds */
f535537f 1268#define ZSTD_TARGETCBLOCKSIZE_MIN 1340 /* suitable to fit into an ethernet / wifi / 4G transport frame */
648db22b 1269#define ZSTD_TARGETCBLOCKSIZE_MAX ZSTD_BLOCKSIZE_MAX
1270#define ZSTD_SRCSIZEHINT_MIN 0
1271#define ZSTD_SRCSIZEHINT_MAX INT_MAX
1272
1273
1274/* --- Advanced types --- */
1275
1276typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params;
1277
1278typedef struct {
1279 unsigned int offset; /* The offset of the match. (NOT the same as the offset code)
1280 * If offset == 0 and matchLength == 0, this sequence represents the last
1281 * literals in the block of litLength size.
1282 */
1283
1284 unsigned int litLength; /* Literal length of the sequence. */
1285 unsigned int matchLength; /* Match length of the sequence. */
1286
1287 /* Note: Users of this API may provide a sequence with matchLength == litLength == offset == 0.
1288 * In this case, we will treat the sequence as a marker for a block boundary.
1289 */
1290
1291 unsigned int rep; /* Represents which repeat offset is represented by the field 'offset'.
1292 * Ranges from [0, 3].
1293 *
1294 * Repeat offsets are essentially previous offsets from previous sequences sorted in
1295 * recency order. For more detail, see doc/zstd_compression_format.md
1296 *
1297 * If rep == 0, then 'offset' does not contain a repeat offset.
1298 * If rep > 0:
1299 * If litLength != 0:
1300 * rep == 1 --> offset == repeat_offset_1
1301 * rep == 2 --> offset == repeat_offset_2
1302 * rep == 3 --> offset == repeat_offset_3
1303 * If litLength == 0:
1304 * rep == 1 --> offset == repeat_offset_2
1305 * rep == 2 --> offset == repeat_offset_3
1306 * rep == 3 --> offset == repeat_offset_1 - 1
1307 *
1308 * Note: This field is optional. ZSTD_generateSequences() will calculate the value of
1309 * 'rep', but repeat offsets do not necessarily need to be calculated from an external
1310 * sequence provider's perspective. For example, ZSTD_compressSequences() does not
1311 * use this 'rep' field at all (as of now).
1312 */
1313} ZSTD_Sequence;
1314
1315typedef struct {
1316 unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */
1317 unsigned chainLog; /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */
1318 unsigned hashLog; /**< dispatch table : larger == faster, more memory */
1319 unsigned searchLog; /**< nb of searches : larger == more compression, slower */
1320 unsigned minMatch; /**< match length searched : larger == faster decompression, sometimes less compression */
1321 unsigned targetLength; /**< acceptable match size for optimal parser (only) : larger == more compression, slower */
1322 ZSTD_strategy strategy; /**< see ZSTD_strategy definition above */
1323} ZSTD_compressionParameters;
1324
1325typedef struct {
1326 int contentSizeFlag; /**< 1: content size will be in frame header (when known) */
1327 int checksumFlag; /**< 1: generate a 32-bits checksum using XXH64 algorithm at end of frame, for error detection */
1328 int noDictIDFlag; /**< 1: no dictID will be saved into frame header (dictID is only useful for dictionary compression) */
1329} ZSTD_frameParameters;
1330
1331typedef struct {
1332 ZSTD_compressionParameters cParams;
1333 ZSTD_frameParameters fParams;
1334} ZSTD_parameters;
1335
1336typedef enum {
1337 ZSTD_dct_auto = 0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */
1338 ZSTD_dct_rawContent = 1, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */
1339 ZSTD_dct_fullDict = 2 /* refuses to load a dictionary if it does not respect Zstandard's specification, starting with ZSTD_MAGIC_DICTIONARY */
1340} ZSTD_dictContentType_e;
1341
1342typedef enum {
1343 ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */
1344 ZSTD_dlm_byRef = 1 /**< Reference dictionary content -- the dictionary buffer must outlive its users. */
1345} ZSTD_dictLoadMethod_e;
1346
1347typedef enum {
1348 ZSTD_f_zstd1 = 0, /* zstd frame format, specified in zstd_compression_format.md (default) */
1349 ZSTD_f_zstd1_magicless = 1 /* Variant of zstd frame format, without initial 4-bytes magic number.
1350 * Useful to save 4 bytes per generated frame.
1351 * Decoder cannot recognise automatically this format, requiring this instruction. */
1352} ZSTD_format_e;
1353
1354typedef enum {
1355 /* Note: this enum controls ZSTD_d_forceIgnoreChecksum */
1356 ZSTD_d_validateChecksum = 0,
1357 ZSTD_d_ignoreChecksum = 1
1358} ZSTD_forceIgnoreChecksum_e;
1359
1360typedef enum {
1361 /* Note: this enum controls ZSTD_d_refMultipleDDicts */
1362 ZSTD_rmd_refSingleDDict = 0,
1363 ZSTD_rmd_refMultipleDDicts = 1
1364} ZSTD_refMultipleDDicts_e;
1365
1366typedef enum {
1367 /* Note: this enum and the behavior it controls are effectively internal
1368 * implementation details of the compressor. They are expected to continue
1369 * to evolve and should be considered only in the context of extremely
1370 * advanced performance tuning.
1371 *
1372 * Zstd currently supports the use of a CDict in three ways:
1373 *
1374 * - The contents of the CDict can be copied into the working context. This
1375 * means that the compression can search both the dictionary and input
1376 * while operating on a single set of internal tables. This makes
1377 * the compression faster per-byte of input. However, the initial copy of
1378 * the CDict's tables incurs a fixed cost at the beginning of the
1379 * compression. For small compressions (< 8 KB), that copy can dominate
1380 * the cost of the compression.
1381 *
1382 * - The CDict's tables can be used in-place. In this model, compression is
1383 * slower per input byte, because the compressor has to search two sets of
1384 * tables. However, this model incurs no start-up cost (as long as the
1385 * working context's tables can be reused). For small inputs, this can be
1386 * faster than copying the CDict's tables.
1387 *
1388 * - The CDict's tables are not used at all, and instead we use the working
1389 * context alone to reload the dictionary and use params based on the source
1390 * size. See ZSTD_compress_insertDictionary() and ZSTD_compress_usingDict().
1391 * This method is effective when the dictionary sizes are very small relative
1392 * to the input size, and the input size is fairly large to begin with.
1393 *
1394 * Zstd has a simple internal heuristic that selects which strategy to use
1395 * at the beginning of a compression. However, if experimentation shows that
1396 * Zstd is making poor choices, it is possible to override that choice with
1397 * this enum.
1398 */
1399 ZSTD_dictDefaultAttach = 0, /* Use the default heuristic. */
1400 ZSTD_dictForceAttach = 1, /* Never copy the dictionary. */
1401 ZSTD_dictForceCopy = 2, /* Always copy the dictionary. */
1402 ZSTD_dictForceLoad = 3 /* Always reload the dictionary */
1403} ZSTD_dictAttachPref_e;
1404
1405typedef enum {
1406 ZSTD_lcm_auto = 0, /**< Automatically determine the compression mode based on the compression level.
1407 * Negative compression levels will be uncompressed, and positive compression
1408 * levels will be compressed. */
1409 ZSTD_lcm_huffman = 1, /**< Always attempt Huffman compression. Uncompressed literals will still be
1410 * emitted if Huffman compression is not profitable. */
1411 ZSTD_lcm_uncompressed = 2 /**< Always emit uncompressed literals. */
1412} ZSTD_literalCompressionMode_e;
1413
1414typedef enum {
1415 /* Note: This enum controls features which are conditionally beneficial. Zstd typically will make a final
1416 * decision on whether or not to enable the feature (ZSTD_ps_auto), but setting the switch to ZSTD_ps_enable
1417 * or ZSTD_ps_disable allow for a force enable/disable the feature.
1418 */
1419 ZSTD_ps_auto = 0, /* Let the library automatically determine whether the feature shall be enabled */
1420 ZSTD_ps_enable = 1, /* Force-enable the feature */
1421 ZSTD_ps_disable = 2 /* Do not use the feature */
1422} ZSTD_paramSwitch_e;
1423
1424/***************************************
1425* Frame header and size functions
1426***************************************/
1427
1428/*! ZSTD_findDecompressedSize() :
1429 * `src` should point to the start of a series of ZSTD encoded and/or skippable frames
1430 * `srcSize` must be the _exact_ size of this series
1431 * (i.e. there should be a frame boundary at `src + srcSize`)
1432 * @return : - decompressed size of all data in all successive frames
1433 * - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN
1434 * - if an error occurred: ZSTD_CONTENTSIZE_ERROR
1435 *
1436 * note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.
1437 * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.
1438 * In which case, it's necessary to use streaming mode to decompress data.
1439 * note 2 : decompressed size is always present when compression is done with ZSTD_compress()
1440 * note 3 : decompressed size can be very large (64-bits value),
1441 * potentially larger than what local system can handle as a single memory segment.
1442 * In which case, it's necessary to use streaming mode to decompress data.
1443 * note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified.
1444 * Always ensure result fits within application's authorized limits.
1445 * Each application can set its own limits.
1446 * note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to
1447 * read each contained frame header. This is fast as most of the data is skipped,
1448 * however it does mean that all frame data must be present and valid. */
1449ZSTDLIB_STATIC_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize);
1450
1451/*! ZSTD_decompressBound() :
1452 * `src` should point to the start of a series of ZSTD encoded and/or skippable frames
1453 * `srcSize` must be the _exact_ size of this series
1454 * (i.e. there should be a frame boundary at `src + srcSize`)
1455 * @return : - upper-bound for the decompressed size of all data in all successive frames
1456 * - if an error occurred: ZSTD_CONTENTSIZE_ERROR
1457 *
1458 * note 1 : an error can occur if `src` contains an invalid or incorrectly formatted frame.
1459 * note 2 : the upper-bound is exact when the decompressed size field is available in every ZSTD encoded frame of `src`.
1460 * in this case, `ZSTD_findDecompressedSize` and `ZSTD_decompressBound` return the same value.
1461 * note 3 : when the decompressed size field isn't available, the upper-bound for that frame is calculated by:
1462 * upper-bound = # blocks * min(128 KB, Window_Size)
1463 */
1464ZSTDLIB_STATIC_API unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize);
1465
1466/*! ZSTD_frameHeaderSize() :
1467 * srcSize must be >= ZSTD_FRAMEHEADERSIZE_PREFIX.
1468 * @return : size of the Frame Header,
1469 * or an error code (if srcSize is too small) */
1470ZSTDLIB_STATIC_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize);
1471
1472typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e;
1473typedef struct {
1474 unsigned long long frameContentSize; /* if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty" */
1475 unsigned long long windowSize; /* can be very large, up to <= frameContentSize */
1476 unsigned blockSizeMax;
1477 ZSTD_frameType_e frameType; /* if == ZSTD_skippableFrame, frameContentSize is the size of skippable content */
1478 unsigned headerSize;
1479 unsigned dictID;
1480 unsigned checksumFlag;
1481 unsigned _reserved1;
1482 unsigned _reserved2;
1483} ZSTD_frameHeader;
1484
1485/*! ZSTD_getFrameHeader() :
1486 * decode Frame Header, or requires larger `srcSize`.
1487 * @return : 0, `zfhPtr` is correctly filled,
1488 * >0, `srcSize` is too small, value is wanted `srcSize` amount,
1489 * or an error code, which can be tested using ZSTD_isError() */
1490ZSTDLIB_STATIC_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /**< doesn't consume input */
1491/*! ZSTD_getFrameHeader_advanced() :
1492 * same as ZSTD_getFrameHeader(),
1493 * with added capability to select a format (like ZSTD_f_zstd1_magicless) */
1494ZSTDLIB_STATIC_API size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format);
1495
1496/*! ZSTD_decompressionMargin() :
1497 * Zstd supports in-place decompression, where the input and output buffers overlap.
1498 * In this case, the output buffer must be at least (Margin + Output_Size) bytes large,
1499 * and the input buffer must be at the end of the output buffer.
1500 *
1501 * _______________________ Output Buffer ________________________
1502 * | |
1503 * | ____ Input Buffer ____|
1504 * | | |
1505 * v v v
1506 * |---------------------------------------|-----------|----------|
1507 * ^ ^ ^
1508 * |___________________ Output_Size ___________________|_ Margin _|
1509 *
1510 * NOTE: See also ZSTD_DECOMPRESSION_MARGIN().
1511 * NOTE: This applies only to single-pass decompression through ZSTD_decompress() or
1512 * ZSTD_decompressDCtx().
1513 * NOTE: This function supports multi-frame input.
1514 *
1515 * @param src The compressed frame(s)
1516 * @param srcSize The size of the compressed frame(s)
1517 * @returns The decompression margin or an error that can be checked with ZSTD_isError().
1518 */
1519ZSTDLIB_STATIC_API size_t ZSTD_decompressionMargin(const void* src, size_t srcSize);
1520
1521/*! ZSTD_DECOMPRESS_MARGIN() :
1522 * Similar to ZSTD_decompressionMargin(), but instead of computing the margin from
1523 * the compressed frame, compute it from the original size and the blockSizeLog.
1524 * See ZSTD_decompressionMargin() for details.
1525 *
1526 * WARNING: This macro does not support multi-frame input, the input must be a single
1527 * zstd frame. If you need that support use the function, or implement it yourself.
1528 *
1529 * @param originalSize The original uncompressed size of the data.
1530 * @param blockSize The block size == MIN(windowSize, ZSTD_BLOCKSIZE_MAX).
1531 * Unless you explicitly set the windowLog smaller than
1532 * ZSTD_BLOCKSIZELOG_MAX you can just use ZSTD_BLOCKSIZE_MAX.
1533 */
1534#define ZSTD_DECOMPRESSION_MARGIN(originalSize, blockSize) ((size_t)( \
1535 ZSTD_FRAMEHEADERSIZE_MAX /* Frame header */ + \
1536 4 /* checksum */ + \
1537 ((originalSize) == 0 ? 0 : 3 * (((originalSize) + (blockSize) - 1) / blockSize)) /* 3 bytes per block */ + \
1538 (blockSize) /* One block of margin */ \
1539 ))
1540
1541typedef enum {
1542 ZSTD_sf_noBlockDelimiters = 0, /* Representation of ZSTD_Sequence has no block delimiters, sequences only */
1543 ZSTD_sf_explicitBlockDelimiters = 1 /* Representation of ZSTD_Sequence contains explicit block delimiters */
1544} ZSTD_sequenceFormat_e;
1545
1546/*! ZSTD_sequenceBound() :
1547 * `srcSize` : size of the input buffer
1548 * @return : upper-bound for the number of sequences that can be generated
1549 * from a buffer of srcSize bytes
1550 *
1551 * note : returns number of sequences - to get bytes, multiply by sizeof(ZSTD_Sequence).
1552 */
1553ZSTDLIB_STATIC_API size_t ZSTD_sequenceBound(size_t srcSize);
1554
1555/*! ZSTD_generateSequences() :
f535537f 1556 * WARNING: This function is meant for debugging and informational purposes ONLY!
1557 * Its implementation is flawed, and it will be deleted in a future version.
1558 * It is not guaranteed to succeed, as there are several cases where it will give
1559 * up and fail. You should NOT use this function in production code.
1560 *
1561 * This function is deprecated, and will be removed in a future version.
1562 *
648db22b 1563 * Generate sequences using ZSTD_compress2(), given a source buffer.
1564 *
f535537f 1565 * @param zc The compression context to be used for ZSTD_compress2(). Set any
1566 * compression parameters you need on this context.
1567 * @param outSeqs The output sequences buffer of size @p outSeqsSize
1568 * @param outSeqsSize The size of the output sequences buffer.
1569 * ZSTD_sequenceBound(srcSize) is an upper bound on the number
1570 * of sequences that can be generated.
1571 * @param src The source buffer to generate sequences from of size @p srcSize.
1572 * @param srcSize The size of the source buffer.
1573 *
648db22b 1574 * Each block will end with a dummy sequence
1575 * with offset == 0, matchLength == 0, and litLength == length of last literals.
1576 * litLength may be == 0, and if so, then the sequence of (of: 0 ml: 0 ll: 0)
1577 * simply acts as a block delimiter.
1578 *
f535537f 1579 * @returns The number of sequences generated, necessarily less than
1580 * ZSTD_sequenceBound(srcSize), or an error code that can be checked
1581 * with ZSTD_isError().
648db22b 1582 */
f535537f 1583ZSTD_DEPRECATED("For debugging only, will be replaced by ZSTD_extractSequences()")
648db22b 1584ZSTDLIB_STATIC_API size_t
f535537f 1585ZSTD_generateSequences(ZSTD_CCtx* zc,
1586 ZSTD_Sequence* outSeqs, size_t outSeqsSize,
1587 const void* src, size_t srcSize);
648db22b 1588
1589/*! ZSTD_mergeBlockDelimiters() :
1590 * Given an array of ZSTD_Sequence, remove all sequences that represent block delimiters/last literals
1591 * by merging them into the literals of the next sequence.
1592 *
1593 * As such, the final generated result has no explicit representation of block boundaries,
1594 * and the final last literals segment is not represented in the sequences.
1595 *
1596 * The output of this function can be fed into ZSTD_compressSequences() with CCtx
1597 * setting of ZSTD_c_blockDelimiters as ZSTD_sf_noBlockDelimiters
1598 * @return : number of sequences left after merging
1599 */
1600ZSTDLIB_STATIC_API size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, size_t seqsSize);
1601
1602/*! ZSTD_compressSequences() :
1603 * Compress an array of ZSTD_Sequence, associated with @src buffer, into dst.
1604 * @src contains the entire input (not just the literals).
1605 * If @srcSize > sum(sequence.length), the remaining bytes are considered all literals
1606 * If a dictionary is included, then the cctx should reference the dict. (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.)
1607 * The entire source is compressed into a single frame.
1608 *
1609 * The compression behavior changes based on cctx params. In particular:
1610 * If ZSTD_c_blockDelimiters == ZSTD_sf_noBlockDelimiters, the array of ZSTD_Sequence is expected to contain
1611 * no block delimiters (defined in ZSTD_Sequence). Block boundaries are roughly determined based on
1612 * the block size derived from the cctx, and sequences may be split. This is the default setting.
1613 *
1614 * If ZSTD_c_blockDelimiters == ZSTD_sf_explicitBlockDelimiters, the array of ZSTD_Sequence is expected to contain
1615 * block delimiters (defined in ZSTD_Sequence). Behavior is undefined if no block delimiters are provided.
1616 *
1617 * If ZSTD_c_validateSequences == 0, this function will blindly accept the sequences provided. Invalid sequences cause undefined
1618 * behavior. If ZSTD_c_validateSequences == 1, then if sequence is invalid (see doc/zstd_compression_format.md for
1619 * specifics regarding offset/matchlength requirements) then the function will bail out and return an error.
1620 *
1621 * In addition to the two adjustable experimental params, there are other important cctx params.
1622 * - ZSTD_c_minMatch MUST be set as less than or equal to the smallest match generated by the match finder. It has a minimum value of ZSTD_MINMATCH_MIN.
1623 * - ZSTD_c_compressionLevel accordingly adjusts the strength of the entropy coder, as it would in typical compression.
1624 * - ZSTD_c_windowLog affects offset validation: this function will return an error at higher debug levels if a provided offset
1625 * is larger than what the spec allows for a given window log and dictionary (if present). See: doc/zstd_compression_format.md
1626 *
1627 * Note: Repcodes are, as of now, always re-calculated within this function, so ZSTD_Sequence::rep is unused.
1628 * Note 2: Once we integrate ability to ingest repcodes, the explicit block delims mode must respect those repcodes exactly,
1629 * and cannot emit an RLE block that disagrees with the repcode history
1630 * @return : final compressed size, or a ZSTD error code.
1631 */
1632ZSTDLIB_STATIC_API size_t
1633ZSTD_compressSequences( ZSTD_CCtx* cctx, void* dst, size_t dstSize,
1634 const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
1635 const void* src, size_t srcSize);
1636
1637
1638/*! ZSTD_writeSkippableFrame() :
1639 * Generates a zstd skippable frame containing data given by src, and writes it to dst buffer.
1640 *
1641 * Skippable frames begin with a 4-byte magic number. There are 16 possible choices of magic number,
1642 * ranging from ZSTD_MAGIC_SKIPPABLE_START to ZSTD_MAGIC_SKIPPABLE_START+15.
1643 * As such, the parameter magicVariant controls the exact skippable frame magic number variant used, so
1644 * the magic number used will be ZSTD_MAGIC_SKIPPABLE_START + magicVariant.
1645 *
1646 * Returns an error if destination buffer is not large enough, if the source size is not representable
1647 * with a 4-byte unsigned int, or if the parameter magicVariant is greater than 15 (and therefore invalid).
1648 *
1649 * @return : number of bytes written or a ZSTD error.
1650 */
1651ZSTDLIB_STATIC_API size_t ZSTD_writeSkippableFrame(void* dst, size_t dstCapacity,
1652 const void* src, size_t srcSize, unsigned magicVariant);
1653
1654/*! ZSTD_readSkippableFrame() :
1655 * Retrieves a zstd skippable frame containing data given by src, and writes it to dst buffer.
1656 *
1657 * The parameter magicVariant will receive the magicVariant that was supplied when the frame was written,
1658 * i.e. magicNumber - ZSTD_MAGIC_SKIPPABLE_START. This can be NULL if the caller is not interested
1659 * in the magicVariant.
1660 *
1661 * Returns an error if destination buffer is not large enough, or if the frame is not skippable.
1662 *
1663 * @return : number of bytes written or a ZSTD error.
1664 */
1665ZSTDLIB_API size_t ZSTD_readSkippableFrame(void* dst, size_t dstCapacity, unsigned* magicVariant,
1666 const void* src, size_t srcSize);
1667
1668/*! ZSTD_isSkippableFrame() :
1669 * Tells if the content of `buffer` starts with a valid Frame Identifier for a skippable frame.
1670 */
1671ZSTDLIB_API unsigned ZSTD_isSkippableFrame(const void* buffer, size_t size);
1672
1673
1674
1675/***************************************
1676* Memory management
1677***************************************/
1678
1679/*! ZSTD_estimate*() :
1680 * These functions make it possible to estimate memory usage
1681 * of a future {D,C}Ctx, before its creation.
f535537f 1682 * This is useful in combination with ZSTD_initStatic(),
1683 * which makes it possible to employ a static buffer for ZSTD_CCtx* state.
648db22b 1684 *
1685 * ZSTD_estimateCCtxSize() will provide a memory budget large enough
f535537f 1686 * to compress data of any size using one-shot compression ZSTD_compressCCtx() or ZSTD_compress2()
1687 * associated with any compression level up to max specified one.
648db22b 1688 * The estimate will assume the input may be arbitrarily large,
1689 * which is the worst case.
1690 *
f535537f 1691 * Note that the size estimation is specific for one-shot compression,
1692 * it is not valid for streaming (see ZSTD_estimateCStreamSize*())
1693 * nor other potential ways of using a ZSTD_CCtx* state.
1694 *
648db22b 1695 * When srcSize can be bound by a known and rather "small" value,
f535537f 1696 * this knowledge can be used to provide a tighter budget estimation
1697 * because the ZSTD_CCtx* state will need less memory for small inputs.
1698 * This tighter estimation can be provided by employing more advanced functions
648db22b 1699 * ZSTD_estimateCCtxSize_usingCParams(), which can be used in tandem with ZSTD_getCParams(),
1700 * and ZSTD_estimateCCtxSize_usingCCtxParams(), which can be used in tandem with ZSTD_CCtxParams_setParameter().
1701 * Both can be used to estimate memory using custom compression parameters and arbitrary srcSize limits.
1702 *
1703 * Note : only single-threaded compression is supported.
1704 * ZSTD_estimateCCtxSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1.
648db22b 1705 */
f535537f 1706ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize(int maxCompressionLevel);
648db22b 1707ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams);
1708ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params);
1709ZSTDLIB_STATIC_API size_t ZSTD_estimateDCtxSize(void);
1710
1711/*! ZSTD_estimateCStreamSize() :
f535537f 1712 * ZSTD_estimateCStreamSize() will provide a memory budget large enough for streaming compression
1713 * using any compression level up to the max specified one.
1714 * It will also consider src size to be arbitrarily "large", which is a worst case scenario.
648db22b 1715 * If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation.
1716 * ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel.
1717 * ZSTD_estimateCStreamSize_usingCCtxParams() can be used in tandem with ZSTD_CCtxParams_setParameter(). Only single-threaded compression is supported. This function will return an error code if ZSTD_c_nbWorkers is >= 1.
1718 * Note : CStream size estimation is only correct for single-threaded compression.
f535537f 1719 * ZSTD_estimateCStreamSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1.
1720 * Note 2 : ZSTD_estimateCStreamSize* functions are not compatible with the Block-Level Sequence Producer API at this time.
1721 * Size estimates assume that no external sequence producer is registered.
1722 *
1723 * ZSTD_DStream memory budget depends on frame's window Size.
648db22b 1724 * This information can be passed manually, using ZSTD_estimateDStreamSize,
1725 * or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame();
f535537f 1726 * Any frame requesting a window size larger than max specified one will be rejected.
648db22b 1727 * Note : if streaming is init with function ZSTD_init?Stream_usingDict(),
1728 * an internal ?Dict will be created, which additional size is not estimated here.
1729 * In this case, get total size by adding ZSTD_estimate?DictSize
648db22b 1730 */
f535537f 1731ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize(int maxCompressionLevel);
648db22b 1732ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams);
1733ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params);
f535537f 1734ZSTDLIB_STATIC_API size_t ZSTD_estimateDStreamSize(size_t maxWindowSize);
648db22b 1735ZSTDLIB_STATIC_API size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize);
1736
1737/*! ZSTD_estimate?DictSize() :
1738 * ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict().
1739 * ZSTD_estimateCDictSize_advanced() makes it possible to control compression parameters precisely, like ZSTD_createCDict_advanced().
1740 * Note : dictionaries created by reference (`ZSTD_dlm_byRef`) are logically smaller.
1741 */
1742ZSTDLIB_STATIC_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel);
1743ZSTDLIB_STATIC_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod);
1744ZSTDLIB_STATIC_API size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod);
1745
1746/*! ZSTD_initStatic*() :
1747 * Initialize an object using a pre-allocated fixed-size buffer.
1748 * workspace: The memory area to emplace the object into.
1749 * Provided pointer *must be 8-bytes aligned*.
1750 * Buffer must outlive object.
1751 * workspaceSize: Use ZSTD_estimate*Size() to determine
1752 * how large workspace must be to support target scenario.
1753 * @return : pointer to object (same address as workspace, just different type),
1754 * or NULL if error (size too small, incorrect alignment, etc.)
1755 * Note : zstd will never resize nor malloc() when using a static buffer.
1756 * If the object requires more memory than available,
1757 * zstd will just error out (typically ZSTD_error_memory_allocation).
1758 * Note 2 : there is no corresponding "free" function.
1759 * Since workspace is allocated externally, it must be freed externally too.
1760 * Note 3 : cParams : use ZSTD_getCParams() to convert a compression level
1761 * into its associated cParams.
1762 * Limitation 1 : currently not compatible with internal dictionary creation, triggered by
1763 * ZSTD_CCtx_loadDictionary(), ZSTD_initCStream_usingDict() or ZSTD_initDStream_usingDict().
1764 * Limitation 2 : static cctx currently not compatible with multi-threading.
1765 * Limitation 3 : static dctx is incompatible with legacy support.
1766 */
1767ZSTDLIB_STATIC_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize);
1768ZSTDLIB_STATIC_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticCCtx() */
1769
1770ZSTDLIB_STATIC_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize);
1771ZSTDLIB_STATIC_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticDCtx() */
1772
1773ZSTDLIB_STATIC_API const ZSTD_CDict* ZSTD_initStaticCDict(
1774 void* workspace, size_t workspaceSize,
1775 const void* dict, size_t dictSize,
1776 ZSTD_dictLoadMethod_e dictLoadMethod,
1777 ZSTD_dictContentType_e dictContentType,
1778 ZSTD_compressionParameters cParams);
1779
1780ZSTDLIB_STATIC_API const ZSTD_DDict* ZSTD_initStaticDDict(
1781 void* workspace, size_t workspaceSize,
1782 const void* dict, size_t dictSize,
1783 ZSTD_dictLoadMethod_e dictLoadMethod,
1784 ZSTD_dictContentType_e dictContentType);
1785
1786
1787/*! Custom memory allocation :
1788 * These prototypes make it possible to pass your own allocation/free functions.
1789 * ZSTD_customMem is provided at creation time, using ZSTD_create*_advanced() variants listed below.
1790 * All allocation/free operations will be completed using these custom variants instead of regular <stdlib.h> ones.
1791 */
1792typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size);
1793typedef void (*ZSTD_freeFunction) (void* opaque, void* address);
1794typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem;
1795static
1796#ifdef __GNUC__
1797__attribute__((__unused__))
1798#endif
1799ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; /**< this constant defers to stdlib's functions */
1800
1801ZSTDLIB_STATIC_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
1802ZSTDLIB_STATIC_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem);
1803ZSTDLIB_STATIC_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem);
1804ZSTDLIB_STATIC_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem);
1805
1806ZSTDLIB_STATIC_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize,
1807 ZSTD_dictLoadMethod_e dictLoadMethod,
1808 ZSTD_dictContentType_e dictContentType,
1809 ZSTD_compressionParameters cParams,
1810 ZSTD_customMem customMem);
1811
1812/*! Thread pool :
1813 * These prototypes make it possible to share a thread pool among multiple compression contexts.
1814 * This can limit resources for applications with multiple threads where each one uses
1815 * a threaded compression mode (via ZSTD_c_nbWorkers parameter).
1816 * ZSTD_createThreadPool creates a new thread pool with a given number of threads.
1817 * Note that the lifetime of such pool must exist while being used.
1818 * ZSTD_CCtx_refThreadPool assigns a thread pool to a context (use NULL argument value
1819 * to use an internal thread pool).
1820 * ZSTD_freeThreadPool frees a thread pool, accepts NULL pointer.
1821 */
1822typedef struct POOL_ctx_s ZSTD_threadPool;
1823ZSTDLIB_STATIC_API ZSTD_threadPool* ZSTD_createThreadPool(size_t numThreads);
1824ZSTDLIB_STATIC_API void ZSTD_freeThreadPool (ZSTD_threadPool* pool); /* accept NULL pointer */
1825ZSTDLIB_STATIC_API size_t ZSTD_CCtx_refThreadPool(ZSTD_CCtx* cctx, ZSTD_threadPool* pool);
1826
1827
1828/*
1829 * This API is temporary and is expected to change or disappear in the future!
1830 */
1831ZSTDLIB_STATIC_API ZSTD_CDict* ZSTD_createCDict_advanced2(
1832 const void* dict, size_t dictSize,
1833 ZSTD_dictLoadMethod_e dictLoadMethod,
1834 ZSTD_dictContentType_e dictContentType,
1835 const ZSTD_CCtx_params* cctxParams,
1836 ZSTD_customMem customMem);
1837
1838ZSTDLIB_STATIC_API ZSTD_DDict* ZSTD_createDDict_advanced(
1839 const void* dict, size_t dictSize,
1840 ZSTD_dictLoadMethod_e dictLoadMethod,
1841 ZSTD_dictContentType_e dictContentType,
1842 ZSTD_customMem customMem);
1843
1844
1845/***************************************
1846* Advanced compression functions
1847***************************************/
1848
1849/*! ZSTD_createCDict_byReference() :
1850 * Create a digested dictionary for compression
1851 * Dictionary content is just referenced, not duplicated.
1852 * As a consequence, `dictBuffer` **must** outlive CDict,
1853 * and its content must remain unmodified throughout the lifetime of CDict.
1854 * note: equivalent to ZSTD_createCDict_advanced(), with dictLoadMethod==ZSTD_dlm_byRef */
1855ZSTDLIB_STATIC_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
1856
1857/*! ZSTD_getCParams() :
1858 * @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize.
1859 * `estimatedSrcSize` value is optional, select 0 if not known */
1860ZSTDLIB_STATIC_API ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize);
1861
1862/*! ZSTD_getParams() :
1863 * same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of sub-component `ZSTD_compressionParameters`.
1864 * All fields of `ZSTD_frameParameters` are set to default : contentSize=1, checksum=0, noDictID=0 */
1865ZSTDLIB_STATIC_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize);
1866
1867/*! ZSTD_checkCParams() :
1868 * Ensure param values remain within authorized range.
1869 * @return 0 on success, or an error code (can be checked with ZSTD_isError()) */
1870ZSTDLIB_STATIC_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params);
1871
1872/*! ZSTD_adjustCParams() :
1873 * optimize params for a given `srcSize` and `dictSize`.
1874 * `srcSize` can be unknown, in which case use ZSTD_CONTENTSIZE_UNKNOWN.
1875 * `dictSize` must be `0` when there is no dictionary.
1876 * cPar can be invalid : all parameters will be clamped within valid range in the @return struct.
1877 * This function never fails (wide contract) */
1878ZSTDLIB_STATIC_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize);
1879
1880/*! ZSTD_CCtx_setCParams() :
1881 * Set all parameters provided within @p cparams into the working @p cctx.
1882 * Note : if modifying parameters during compression (MT mode only),
1883 * note that changes to the .windowLog parameter will be ignored.
1884 * @return 0 on success, or an error code (can be checked with ZSTD_isError()).
1885 * On failure, no parameters are updated.
1886 */
1887ZSTDLIB_STATIC_API size_t ZSTD_CCtx_setCParams(ZSTD_CCtx* cctx, ZSTD_compressionParameters cparams);
1888
1889/*! ZSTD_CCtx_setFParams() :
1890 * Set all parameters provided within @p fparams into the working @p cctx.
1891 * @return 0 on success, or an error code (can be checked with ZSTD_isError()).
1892 */
1893ZSTDLIB_STATIC_API size_t ZSTD_CCtx_setFParams(ZSTD_CCtx* cctx, ZSTD_frameParameters fparams);
1894
1895/*! ZSTD_CCtx_setParams() :
1896 * Set all parameters provided within @p params into the working @p cctx.
1897 * @return 0 on success, or an error code (can be checked with ZSTD_isError()).
1898 */
1899ZSTDLIB_STATIC_API size_t ZSTD_CCtx_setParams(ZSTD_CCtx* cctx, ZSTD_parameters params);
1900
1901/*! ZSTD_compress_advanced() :
1902 * Note : this function is now DEPRECATED.
1903 * It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_setParameter() and other parameter setters.
1904 * This prototype will generate compilation warnings. */
1905ZSTD_DEPRECATED("use ZSTD_compress2")
1906ZSTDLIB_STATIC_API
1907size_t ZSTD_compress_advanced(ZSTD_CCtx* cctx,
1908 void* dst, size_t dstCapacity,
1909 const void* src, size_t srcSize,
1910 const void* dict,size_t dictSize,
1911 ZSTD_parameters params);
1912
1913/*! ZSTD_compress_usingCDict_advanced() :
1914 * Note : this function is now DEPRECATED.
1915 * It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_loadDictionary() and other parameter setters.
1916 * This prototype will generate compilation warnings. */
1917ZSTD_DEPRECATED("use ZSTD_compress2 with ZSTD_CCtx_loadDictionary")
1918ZSTDLIB_STATIC_API
1919size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx,
1920 void* dst, size_t dstCapacity,
1921 const void* src, size_t srcSize,
1922 const ZSTD_CDict* cdict,
1923 ZSTD_frameParameters fParams);
1924
1925
1926/*! ZSTD_CCtx_loadDictionary_byReference() :
1927 * Same as ZSTD_CCtx_loadDictionary(), but dictionary content is referenced, instead of being copied into CCtx.
1928 * It saves some memory, but also requires that `dict` outlives its usage within `cctx` */
1929ZSTDLIB_STATIC_API size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
1930
1931/*! ZSTD_CCtx_loadDictionary_advanced() :
1932 * Same as ZSTD_CCtx_loadDictionary(), but gives finer control over
1933 * how to load the dictionary (by copy ? by reference ?)
1934 * and how to interpret it (automatic ? force raw mode ? full mode only ?) */
1935ZSTDLIB_STATIC_API size_t ZSTD_CCtx_loadDictionary_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType);
1936
1937/*! ZSTD_CCtx_refPrefix_advanced() :
1938 * Same as ZSTD_CCtx_refPrefix(), but gives finer control over
1939 * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */
1940ZSTDLIB_STATIC_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType);
1941
1942/* === experimental parameters === */
1943/* these parameters can be used with ZSTD_setParameter()
1944 * they are not guaranteed to remain supported in the future */
1945
1946 /* Enables rsyncable mode,
1947 * which makes compressed files more rsync friendly
1948 * by adding periodic synchronization points to the compressed data.
1949 * The target average block size is ZSTD_c_jobSize / 2.
1950 * It's possible to modify the job size to increase or decrease
1951 * the granularity of the synchronization point.
1952 * Once the jobSize is smaller than the window size,
1953 * it will result in compression ratio degradation.
1954 * NOTE 1: rsyncable mode only works when multithreading is enabled.
1955 * NOTE 2: rsyncable performs poorly in combination with long range mode,
1956 * since it will decrease the effectiveness of synchronization points,
1957 * though mileage may vary.
1958 * NOTE 3: Rsyncable mode limits maximum compression speed to ~400 MB/s.
1959 * If the selected compression level is already running significantly slower,
1960 * the overall speed won't be significantly impacted.
1961 */
1962 #define ZSTD_c_rsyncable ZSTD_c_experimentalParam1
1963
1964/* Select a compression format.
1965 * The value must be of type ZSTD_format_e.
1966 * See ZSTD_format_e enum definition for details */
1967#define ZSTD_c_format ZSTD_c_experimentalParam2
1968
1969/* Force back-reference distances to remain < windowSize,
1970 * even when referencing into Dictionary content (default:0) */
1971#define ZSTD_c_forceMaxWindow ZSTD_c_experimentalParam3
1972
1973/* Controls whether the contents of a CDict
1974 * are used in place, or copied into the working context.
1975 * Accepts values from the ZSTD_dictAttachPref_e enum.
1976 * See the comments on that enum for an explanation of the feature. */
1977#define ZSTD_c_forceAttachDict ZSTD_c_experimentalParam4
1978
1979/* Controlled with ZSTD_paramSwitch_e enum.
1980 * Default is ZSTD_ps_auto.
1981 * Set to ZSTD_ps_disable to never compress literals.
1982 * Set to ZSTD_ps_enable to always compress literals. (Note: uncompressed literals
1983 * may still be emitted if huffman is not beneficial to use.)
1984 *
1985 * By default, in ZSTD_ps_auto, the library will decide at runtime whether to use
1986 * literals compression based on the compression parameters - specifically,
1987 * negative compression levels do not use literal compression.
1988 */
1989#define ZSTD_c_literalCompressionMode ZSTD_c_experimentalParam5
1990
648db22b 1991/* User's best guess of source size.
1992 * Hint is not valid when srcSizeHint == 0.
1993 * There is no guarantee that hint is close to actual source size,
1994 * but compression ratio may regress significantly if guess considerably underestimates */
1995#define ZSTD_c_srcSizeHint ZSTD_c_experimentalParam7
1996
1997/* Controls whether the new and experimental "dedicated dictionary search
1998 * structure" can be used. This feature is still rough around the edges, be
1999 * prepared for surprising behavior!
2000 *
2001 * How to use it:
2002 *
2003 * When using a CDict, whether to use this feature or not is controlled at
2004 * CDict creation, and it must be set in a CCtxParams set passed into that
2005 * construction (via ZSTD_createCDict_advanced2()). A compression will then
2006 * use the feature or not based on how the CDict was constructed; the value of
2007 * this param, set in the CCtx, will have no effect.
2008 *
2009 * However, when a dictionary buffer is passed into a CCtx, such as via
2010 * ZSTD_CCtx_loadDictionary(), this param can be set on the CCtx to control
2011 * whether the CDict that is created internally can use the feature or not.
2012 *
2013 * What it does:
2014 *
2015 * Normally, the internal data structures of the CDict are analogous to what
2016 * would be stored in a CCtx after compressing the contents of a dictionary.
2017 * To an approximation, a compression using a dictionary can then use those
2018 * data structures to simply continue what is effectively a streaming
2019 * compression where the simulated compression of the dictionary left off.
2020 * Which is to say, the search structures in the CDict are normally the same
2021 * format as in the CCtx.
2022 *
2023 * It is possible to do better, since the CDict is not like a CCtx: the search
2024 * structures are written once during CDict creation, and then are only read
2025 * after that, while the search structures in the CCtx are both read and
2026 * written as the compression goes along. This means we can choose a search
2027 * structure for the dictionary that is read-optimized.
2028 *
2029 * This feature enables the use of that different structure.
2030 *
2031 * Note that some of the members of the ZSTD_compressionParameters struct have
2032 * different semantics and constraints in the dedicated search structure. It is
2033 * highly recommended that you simply set a compression level in the CCtxParams
2034 * you pass into the CDict creation call, and avoid messing with the cParams
2035 * directly.
2036 *
2037 * Effects:
2038 *
2039 * This will only have any effect when the selected ZSTD_strategy
2040 * implementation supports this feature. Currently, that's limited to
2041 * ZSTD_greedy, ZSTD_lazy, and ZSTD_lazy2.
2042 *
2043 * Note that this means that the CDict tables can no longer be copied into the
2044 * CCtx, so the dict attachment mode ZSTD_dictForceCopy will no longer be
2045 * usable. The dictionary can only be attached or reloaded.
2046 *
2047 * In general, you should expect compression to be faster--sometimes very much
2048 * so--and CDict creation to be slightly slower. Eventually, we will probably
2049 * make this mode the default.
2050 */
2051#define ZSTD_c_enableDedicatedDictSearch ZSTD_c_experimentalParam8
2052
2053/* ZSTD_c_stableInBuffer
2054 * Experimental parameter.
2055 * Default is 0 == disabled. Set to 1 to enable.
2056 *
2057 * Tells the compressor that input data presented with ZSTD_inBuffer
2058 * will ALWAYS be the same between calls.
2059 * Technically, the @src pointer must never be changed,
2060 * and the @pos field can only be updated by zstd.
2061 * However, it's possible to increase the @size field,
2062 * allowing scenarios where more data can be appended after compressions starts.
2063 * These conditions are checked by the compressor,
2064 * and compression will fail if they are not respected.
2065 * Also, data in the ZSTD_inBuffer within the range [src, src + pos)
2066 * MUST not be modified during compression or it will result in data corruption.
2067 *
2068 * When this flag is enabled zstd won't allocate an input window buffer,
2069 * because the user guarantees it can reference the ZSTD_inBuffer until
2070 * the frame is complete. But, it will still allocate an output buffer
2071 * large enough to fit a block (see ZSTD_c_stableOutBuffer). This will also
2072 * avoid the memcpy() from the input buffer to the input window buffer.
2073 *
2074 * NOTE: So long as the ZSTD_inBuffer always points to valid memory, using
2075 * this flag is ALWAYS memory safe, and will never access out-of-bounds
2076 * memory. However, compression WILL fail if conditions are not respected.
2077 *
2078 * WARNING: The data in the ZSTD_inBuffer in the range [src, src + pos) MUST
2079 * not be modified during compression or it will result in data corruption.
2080 * This is because zstd needs to reference data in the ZSTD_inBuffer to find
2081 * matches. Normally zstd maintains its own window buffer for this purpose,
2082 * but passing this flag tells zstd to rely on user provided buffer instead.
2083 */
2084#define ZSTD_c_stableInBuffer ZSTD_c_experimentalParam9
2085
2086/* ZSTD_c_stableOutBuffer
2087 * Experimental parameter.
2088 * Default is 0 == disabled. Set to 1 to enable.
2089 *
2090 * Tells he compressor that the ZSTD_outBuffer will not be resized between
2091 * calls. Specifically: (out.size - out.pos) will never grow. This gives the
2092 * compressor the freedom to say: If the compressed data doesn't fit in the
2093 * output buffer then return ZSTD_error_dstSizeTooSmall. This allows us to
2094 * always decompress directly into the output buffer, instead of decompressing
2095 * into an internal buffer and copying to the output buffer.
2096 *
2097 * When this flag is enabled zstd won't allocate an output buffer, because
2098 * it can write directly to the ZSTD_outBuffer. It will still allocate the
2099 * input window buffer (see ZSTD_c_stableInBuffer).
2100 *
2101 * Zstd will check that (out.size - out.pos) never grows and return an error
2102 * if it does. While not strictly necessary, this should prevent surprises.
2103 */
2104#define ZSTD_c_stableOutBuffer ZSTD_c_experimentalParam10
2105
2106/* ZSTD_c_blockDelimiters
2107 * Default is 0 == ZSTD_sf_noBlockDelimiters.
2108 *
2109 * For use with sequence compression API: ZSTD_compressSequences().
2110 *
2111 * Designates whether or not the given array of ZSTD_Sequence contains block delimiters
2112 * and last literals, which are defined as sequences with offset == 0 and matchLength == 0.
2113 * See the definition of ZSTD_Sequence for more specifics.
2114 */
2115#define ZSTD_c_blockDelimiters ZSTD_c_experimentalParam11
2116
2117/* ZSTD_c_validateSequences
2118 * Default is 0 == disabled. Set to 1 to enable sequence validation.
2119 *
2120 * For use with sequence compression API: ZSTD_compressSequences().
2121 * Designates whether or not we validate sequences provided to ZSTD_compressSequences()
2122 * during function execution.
2123 *
2124 * Without validation, providing a sequence that does not conform to the zstd spec will cause
2125 * undefined behavior, and may produce a corrupted block.
2126 *
2127 * With validation enabled, if sequence is invalid (see doc/zstd_compression_format.md for
2128 * specifics regarding offset/matchlength requirements) then the function will bail out and
2129 * return an error.
2130 *
2131 */
2132#define ZSTD_c_validateSequences ZSTD_c_experimentalParam12
2133
2134/* ZSTD_c_useBlockSplitter
2135 * Controlled with ZSTD_paramSwitch_e enum.
2136 * Default is ZSTD_ps_auto.
2137 * Set to ZSTD_ps_disable to never use block splitter.
2138 * Set to ZSTD_ps_enable to always use block splitter.
2139 *
2140 * By default, in ZSTD_ps_auto, the library will decide at runtime whether to use
2141 * block splitting based on the compression parameters.
2142 */
2143#define ZSTD_c_useBlockSplitter ZSTD_c_experimentalParam13
2144
2145/* ZSTD_c_useRowMatchFinder
2146 * Controlled with ZSTD_paramSwitch_e enum.
2147 * Default is ZSTD_ps_auto.
2148 * Set to ZSTD_ps_disable to never use row-based matchfinder.
2149 * Set to ZSTD_ps_enable to force usage of row-based matchfinder.
2150 *
2151 * By default, in ZSTD_ps_auto, the library will decide at runtime whether to use
2152 * the row-based matchfinder based on support for SIMD instructions and the window log.
2153 * Note that this only pertains to compression strategies: greedy, lazy, and lazy2
2154 */
2155#define ZSTD_c_useRowMatchFinder ZSTD_c_experimentalParam14
2156
2157/* ZSTD_c_deterministicRefPrefix
2158 * Default is 0 == disabled. Set to 1 to enable.
2159 *
2160 * Zstd produces different results for prefix compression when the prefix is
2161 * directly adjacent to the data about to be compressed vs. when it isn't.
2162 * This is because zstd detects that the two buffers are contiguous and it can
2163 * use a more efficient match finding algorithm. However, this produces different
2164 * results than when the two buffers are non-contiguous. This flag forces zstd
2165 * to always load the prefix in non-contiguous mode, even if it happens to be
2166 * adjacent to the data, to guarantee determinism.
2167 *
2168 * If you really care about determinism when using a dictionary or prefix,
2169 * like when doing delta compression, you should select this option. It comes
2170 * at a speed penalty of about ~2.5% if the dictionary and data happened to be
2171 * contiguous, and is free if they weren't contiguous. We don't expect that
2172 * intentionally making the dictionary and data contiguous will be worth the
2173 * cost to memcpy() the data.
2174 */
2175#define ZSTD_c_deterministicRefPrefix ZSTD_c_experimentalParam15
2176
2177/* ZSTD_c_prefetchCDictTables
2178 * Controlled with ZSTD_paramSwitch_e enum. Default is ZSTD_ps_auto.
2179 *
2180 * In some situations, zstd uses CDict tables in-place rather than copying them
2181 * into the working context. (See docs on ZSTD_dictAttachPref_e above for details).
2182 * In such situations, compression speed is seriously impacted when CDict tables are
2183 * "cold" (outside CPU cache). This parameter instructs zstd to prefetch CDict tables
2184 * when they are used in-place.
2185 *
2186 * For sufficiently small inputs, the cost of the prefetch will outweigh the benefit.
2187 * For sufficiently large inputs, zstd will by default memcpy() CDict tables
2188 * into the working context, so there is no need to prefetch. This parameter is
2189 * targeted at a middle range of input sizes, where a prefetch is cheap enough to be
2190 * useful but memcpy() is too expensive. The exact range of input sizes where this
2191 * makes sense is best determined by careful experimentation.
2192 *
2193 * Note: for this parameter, ZSTD_ps_auto is currently equivalent to ZSTD_ps_disable,
2194 * but in the future zstd may conditionally enable this feature via an auto-detection
2195 * heuristic for cold CDicts.
2196 * Use ZSTD_ps_disable to opt out of prefetching under any circumstances.
2197 */
2198#define ZSTD_c_prefetchCDictTables ZSTD_c_experimentalParam16
2199
2200/* ZSTD_c_enableSeqProducerFallback
2201 * Allowed values are 0 (disable) and 1 (enable). The default setting is 0.
2202 *
2203 * Controls whether zstd will fall back to an internal sequence producer if an
2204 * external sequence producer is registered and returns an error code. This fallback
2205 * is block-by-block: the internal sequence producer will only be called for blocks
2206 * where the external sequence producer returns an error code. Fallback parsing will
2207 * follow any other cParam settings, such as compression level, the same as in a
2208 * normal (fully-internal) compression operation.
2209 *
2210 * The user is strongly encouraged to read the full Block-Level Sequence Producer API
2211 * documentation (below) before setting this parameter. */
2212#define ZSTD_c_enableSeqProducerFallback ZSTD_c_experimentalParam17
2213
2214/* ZSTD_c_maxBlockSize
2215 * Allowed values are between 1KB and ZSTD_BLOCKSIZE_MAX (128KB).
2216 * The default is ZSTD_BLOCKSIZE_MAX, and setting to 0 will set to the default.
2217 *
2218 * This parameter can be used to set an upper bound on the blocksize
2219 * that overrides the default ZSTD_BLOCKSIZE_MAX. It cannot be used to set upper
2220 * bounds greater than ZSTD_BLOCKSIZE_MAX or bounds lower than 1KB (will make
2221 * compressBound() inaccurate). Only currently meant to be used for testing.
2222 *
2223 */
2224#define ZSTD_c_maxBlockSize ZSTD_c_experimentalParam18
2225
2226/* ZSTD_c_searchForExternalRepcodes
2227 * This parameter affects how zstd parses external sequences, such as sequences
2228 * provided through the compressSequences() API or from an external block-level
2229 * sequence producer.
2230 *
2231 * If set to ZSTD_ps_enable, the library will check for repeated offsets in
2232 * external sequences, even if those repcodes are not explicitly indicated in
2233 * the "rep" field. Note that this is the only way to exploit repcode matches
2234 * while using compressSequences() or an external sequence producer, since zstd
2235 * currently ignores the "rep" field of external sequences.
2236 *
2237 * If set to ZSTD_ps_disable, the library will not exploit repeated offsets in
2238 * external sequences, regardless of whether the "rep" field has been set. This
2239 * reduces sequence compression overhead by about 25% while sacrificing some
2240 * compression ratio.
2241 *
2242 * The default value is ZSTD_ps_auto, for which the library will enable/disable
2243 * based on compression level.
2244 *
2245 * Note: for now, this param only has an effect if ZSTD_c_blockDelimiters is
2246 * set to ZSTD_sf_explicitBlockDelimiters. That may change in the future.
2247 */
2248#define ZSTD_c_searchForExternalRepcodes ZSTD_c_experimentalParam19
2249
2250/*! ZSTD_CCtx_getParameter() :
2251 * Get the requested compression parameter value, selected by enum ZSTD_cParameter,
2252 * and store it into int* value.
2253 * @return : 0, or an error code (which can be tested with ZSTD_isError()).
2254 */
2255ZSTDLIB_STATIC_API size_t ZSTD_CCtx_getParameter(const ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value);
2256
2257
2258/*! ZSTD_CCtx_params :
2259 * Quick howto :
2260 * - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure
2261 * - ZSTD_CCtxParams_setParameter() : Push parameters one by one into
2262 * an existing ZSTD_CCtx_params structure.
2263 * This is similar to
2264 * ZSTD_CCtx_setParameter().
2265 * - ZSTD_CCtx_setParametersUsingCCtxParams() : Apply parameters to
2266 * an existing CCtx.
2267 * These parameters will be applied to
2268 * all subsequent frames.
2269 * - ZSTD_compressStream2() : Do compression using the CCtx.
2270 * - ZSTD_freeCCtxParams() : Free the memory, accept NULL pointer.
2271 *
2272 * This can be used with ZSTD_estimateCCtxSize_advanced_usingCCtxParams()
2273 * for static allocation of CCtx for single-threaded compression.
2274 */
2275ZSTDLIB_STATIC_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void);
2276ZSTDLIB_STATIC_API size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params); /* accept NULL pointer */
2277
2278/*! ZSTD_CCtxParams_reset() :
2279 * Reset params to default values.
2280 */
2281ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_reset(ZSTD_CCtx_params* params);
2282
2283/*! ZSTD_CCtxParams_init() :
2284 * Initializes the compression parameters of cctxParams according to
2285 * compression level. All other parameters are reset to their default values.
2286 */
2287ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_init(ZSTD_CCtx_params* cctxParams, int compressionLevel);
2288
2289/*! ZSTD_CCtxParams_init_advanced() :
2290 * Initializes the compression and frame parameters of cctxParams according to
2291 * params. All other parameters are reset to their default values.
2292 */
2293ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params);
2294
2295/*! ZSTD_CCtxParams_setParameter() : Requires v1.4.0+
2296 * Similar to ZSTD_CCtx_setParameter.
2297 * Set one compression parameter, selected by enum ZSTD_cParameter.
2298 * Parameters must be applied to a ZSTD_CCtx using
2299 * ZSTD_CCtx_setParametersUsingCCtxParams().
2300 * @result : a code representing success or failure (which can be tested with
2301 * ZSTD_isError()).
2302 */
2303ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int value);
2304
2305/*! ZSTD_CCtxParams_getParameter() :
2306 * Similar to ZSTD_CCtx_getParameter.
2307 * Get the requested value of one compression parameter, selected by enum ZSTD_cParameter.
2308 * @result : 0, or an error code (which can be tested with ZSTD_isError()).
2309 */
2310ZSTDLIB_STATIC_API size_t ZSTD_CCtxParams_getParameter(const ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value);
2311
2312/*! ZSTD_CCtx_setParametersUsingCCtxParams() :
2313 * Apply a set of ZSTD_CCtx_params to the compression context.
2314 * This can be done even after compression is started,
2315 * if nbWorkers==0, this will have no impact until a new compression is started.
2316 * if nbWorkers>=1, new parameters will be picked up at next job,
2317 * with a few restrictions (windowLog, pledgedSrcSize, nbWorkers, jobSize, and overlapLog are not updated).
2318 */
2319ZSTDLIB_STATIC_API size_t ZSTD_CCtx_setParametersUsingCCtxParams(
2320 ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params);
2321
2322/*! ZSTD_compressStream2_simpleArgs() :
2323 * Same as ZSTD_compressStream2(),
2324 * but using only integral types as arguments.
2325 * This variant might be helpful for binders from dynamic languages
2326 * which have troubles handling structures containing memory pointers.
2327 */
2328ZSTDLIB_STATIC_API size_t ZSTD_compressStream2_simpleArgs (
2329 ZSTD_CCtx* cctx,
2330 void* dst, size_t dstCapacity, size_t* dstPos,
2331 const void* src, size_t srcSize, size_t* srcPos,
2332 ZSTD_EndDirective endOp);
2333
2334
2335/***************************************
2336* Advanced decompression functions
2337***************************************/
2338
2339/*! ZSTD_isFrame() :
2340 * Tells if the content of `buffer` starts with a valid Frame Identifier.
2341 * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0.
2342 * Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled.
2343 * Note 3 : Skippable Frame Identifiers are considered valid. */
2344ZSTDLIB_STATIC_API unsigned ZSTD_isFrame(const void* buffer, size_t size);
2345
2346/*! ZSTD_createDDict_byReference() :
2347 * Create a digested dictionary, ready to start decompression operation without startup delay.
2348 * Dictionary content is referenced, and therefore stays in dictBuffer.
2349 * It is important that dictBuffer outlives DDict,
2350 * it must remain read accessible throughout the lifetime of DDict */
2351ZSTDLIB_STATIC_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize);
2352
2353/*! ZSTD_DCtx_loadDictionary_byReference() :
2354 * Same as ZSTD_DCtx_loadDictionary(),
2355 * but references `dict` content instead of copying it into `dctx`.
2356 * This saves memory if `dict` remains around.,
2357 * However, it's imperative that `dict` remains accessible (and unmodified) while being used, so it must outlive decompression. */
2358ZSTDLIB_STATIC_API size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
2359
2360/*! ZSTD_DCtx_loadDictionary_advanced() :
2361 * Same as ZSTD_DCtx_loadDictionary(),
2362 * but gives direct control over
2363 * how to load the dictionary (by copy ? by reference ?)
2364 * and how to interpret it (automatic ? force raw mode ? full mode only ?). */
2365ZSTDLIB_STATIC_API size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType);
2366
2367/*! ZSTD_DCtx_refPrefix_advanced() :
2368 * Same as ZSTD_DCtx_refPrefix(), but gives finer control over
2369 * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */
2370ZSTDLIB_STATIC_API size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType);
2371
2372/*! ZSTD_DCtx_setMaxWindowSize() :
2373 * Refuses allocating internal buffers for frames requiring a window size larger than provided limit.
2374 * This protects a decoder context from reserving too much memory for itself (potential attack scenario).
2375 * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode.
2376 * By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT)
2377 * @return : 0, or an error code (which can be tested using ZSTD_isError()).
2378 */
2379ZSTDLIB_STATIC_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize);
2380
2381/*! ZSTD_DCtx_getParameter() :
2382 * Get the requested decompression parameter value, selected by enum ZSTD_dParameter,
2383 * and store it into int* value.
2384 * @return : 0, or an error code (which can be tested with ZSTD_isError()).
2385 */
2386ZSTDLIB_STATIC_API size_t ZSTD_DCtx_getParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int* value);
2387
2388/* ZSTD_d_format
2389 * experimental parameter,
2390 * allowing selection between ZSTD_format_e input compression formats
2391 */
2392#define ZSTD_d_format ZSTD_d_experimentalParam1
2393/* ZSTD_d_stableOutBuffer
2394 * Experimental parameter.
2395 * Default is 0 == disabled. Set to 1 to enable.
2396 *
2397 * Tells the decompressor that the ZSTD_outBuffer will ALWAYS be the same
2398 * between calls, except for the modifications that zstd makes to pos (the
2399 * caller must not modify pos). This is checked by the decompressor, and
2400 * decompression will fail if it ever changes. Therefore the ZSTD_outBuffer
2401 * MUST be large enough to fit the entire decompressed frame. This will be
2402 * checked when the frame content size is known. The data in the ZSTD_outBuffer
2403 * in the range [dst, dst + pos) MUST not be modified during decompression
2404 * or you will get data corruption.
2405 *
2406 * When this flag is enabled zstd won't allocate an output buffer, because
2407 * it can write directly to the ZSTD_outBuffer, but it will still allocate
2408 * an input buffer large enough to fit any compressed block. This will also
2409 * avoid the memcpy() from the internal output buffer to the ZSTD_outBuffer.
2410 * If you need to avoid the input buffer allocation use the buffer-less
2411 * streaming API.
2412 *
2413 * NOTE: So long as the ZSTD_outBuffer always points to valid memory, using
2414 * this flag is ALWAYS memory safe, and will never access out-of-bounds
2415 * memory. However, decompression WILL fail if you violate the preconditions.
2416 *
2417 * WARNING: The data in the ZSTD_outBuffer in the range [dst, dst + pos) MUST
2418 * not be modified during decompression or you will get data corruption. This
2419 * is because zstd needs to reference data in the ZSTD_outBuffer to regenerate
2420 * matches. Normally zstd maintains its own buffer for this purpose, but passing
2421 * this flag tells zstd to use the user provided buffer.
2422 */
2423#define ZSTD_d_stableOutBuffer ZSTD_d_experimentalParam2
2424
2425/* ZSTD_d_forceIgnoreChecksum
2426 * Experimental parameter.
2427 * Default is 0 == disabled. Set to 1 to enable
2428 *
2429 * Tells the decompressor to skip checksum validation during decompression, regardless
2430 * of whether checksumming was specified during compression. This offers some
2431 * slight performance benefits, and may be useful for debugging.
2432 * Param has values of type ZSTD_forceIgnoreChecksum_e
2433 */
2434#define ZSTD_d_forceIgnoreChecksum ZSTD_d_experimentalParam3
2435
2436/* ZSTD_d_refMultipleDDicts
2437 * Experimental parameter.
2438 * Default is 0 == disabled. Set to 1 to enable
2439 *
2440 * If enabled and dctx is allocated on the heap, then additional memory will be allocated
2441 * to store references to multiple ZSTD_DDict. That is, multiple calls of ZSTD_refDDict()
2442 * using a given ZSTD_DCtx, rather than overwriting the previous DDict reference, will instead
2443 * store all references. At decompression time, the appropriate dictID is selected
2444 * from the set of DDicts based on the dictID in the frame.
2445 *
2446 * Usage is simply calling ZSTD_refDDict() on multiple dict buffers.
2447 *
2448 * Param has values of byte ZSTD_refMultipleDDicts_e
2449 *
2450 * WARNING: Enabling this parameter and calling ZSTD_DCtx_refDDict(), will trigger memory
2451 * allocation for the hash table. ZSTD_freeDCtx() also frees this memory.
2452 * Memory is allocated as per ZSTD_DCtx::customMem.
2453 *
2454 * Although this function allocates memory for the table, the user is still responsible for
2455 * memory management of the underlying ZSTD_DDict* themselves.
2456 */
2457#define ZSTD_d_refMultipleDDicts ZSTD_d_experimentalParam4
2458
2459/* ZSTD_d_disableHuffmanAssembly
2460 * Set to 1 to disable the Huffman assembly implementation.
2461 * The default value is 0, which allows zstd to use the Huffman assembly
2462 * implementation if available.
2463 *
2464 * This parameter can be used to disable Huffman assembly at runtime.
2465 * If you want to disable it at compile time you can define the macro
2466 * ZSTD_DISABLE_ASM.
2467 */
2468#define ZSTD_d_disableHuffmanAssembly ZSTD_d_experimentalParam5
2469
f535537f 2470/* ZSTD_d_maxBlockSize
2471 * Allowed values are between 1KB and ZSTD_BLOCKSIZE_MAX (128KB).
2472 * The default is ZSTD_BLOCKSIZE_MAX, and setting to 0 will set to the default.
2473 *
2474 * Forces the decompressor to reject blocks whose content size is
2475 * larger than the configured maxBlockSize. When maxBlockSize is
2476 * larger than the windowSize, the windowSize is used instead.
2477 * This saves memory on the decoder when you know all blocks are small.
2478 *
2479 * This option is typically used in conjunction with ZSTD_c_maxBlockSize.
2480 *
2481 * WARNING: This causes the decoder to reject otherwise valid frames
2482 * that have block sizes larger than the configured maxBlockSize.
2483 */
2484#define ZSTD_d_maxBlockSize ZSTD_d_experimentalParam6
2485
648db22b 2486
2487/*! ZSTD_DCtx_setFormat() :
2488 * This function is REDUNDANT. Prefer ZSTD_DCtx_setParameter().
2489 * Instruct the decoder context about what kind of data to decode next.
2490 * This instruction is mandatory to decode data without a fully-formed header,
2491 * such ZSTD_f_zstd1_magicless for example.
2492 * @return : 0, or an error code (which can be tested using ZSTD_isError()). */
2493ZSTD_DEPRECATED("use ZSTD_DCtx_setParameter() instead")
2494ZSTDLIB_STATIC_API
2495size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format);
2496
2497/*! ZSTD_decompressStream_simpleArgs() :
2498 * Same as ZSTD_decompressStream(),
2499 * but using only integral types as arguments.
2500 * This can be helpful for binders from dynamic languages
2501 * which have troubles handling structures containing memory pointers.
2502 */
2503ZSTDLIB_STATIC_API size_t ZSTD_decompressStream_simpleArgs (
2504 ZSTD_DCtx* dctx,
2505 void* dst, size_t dstCapacity, size_t* dstPos,
2506 const void* src, size_t srcSize, size_t* srcPos);
2507
2508
2509/********************************************************************
2510* Advanced streaming functions
2511* Warning : most of these functions are now redundant with the Advanced API.
2512* Once Advanced API reaches "stable" status,
2513* redundant functions will be deprecated, and then at some point removed.
2514********************************************************************/
2515
2516/*===== Advanced Streaming compression functions =====*/
2517
2518/*! ZSTD_initCStream_srcSize() :
2519 * This function is DEPRECATED, and equivalent to:
2520 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
2521 * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any)
2522 * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
2523 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
2524 *
2525 * pledgedSrcSize must be correct. If it is not known at init time, use
2526 * ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs,
2527 * "0" also disables frame content size field. It may be enabled in the future.
2528 * This prototype will generate compilation warnings.
2529 */
2530ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions")
2531ZSTDLIB_STATIC_API
2532size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
2533 int compressionLevel,
2534 unsigned long long pledgedSrcSize);
2535
2536/*! ZSTD_initCStream_usingDict() :
2537 * This function is DEPRECATED, and is equivalent to:
2538 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
2539 * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
2540 * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
2541 *
2542 * Creates of an internal CDict (incompatible with static CCtx), except if
2543 * dict == NULL or dictSize < 8, in which case no dict is used.
2544 * Note: dict is loaded with ZSTD_dct_auto (treated as a full zstd dictionary if
2545 * it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy.
2546 * This prototype will generate compilation warnings.
2547 */
2548ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions")
2549ZSTDLIB_STATIC_API
2550size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs,
2551 const void* dict, size_t dictSize,
2552 int compressionLevel);
2553
2554/*! ZSTD_initCStream_advanced() :
2555 * This function is DEPRECATED, and is equivalent to:
2556 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
2557 * ZSTD_CCtx_setParams(zcs, params);
2558 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
2559 * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
2560 *
2561 * dict is loaded with ZSTD_dct_auto and ZSTD_dlm_byCopy.
2562 * pledgedSrcSize must be correct.
2563 * If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN.
2564 * This prototype will generate compilation warnings.
2565 */
2566ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions")
2567ZSTDLIB_STATIC_API
2568size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
2569 const void* dict, size_t dictSize,
2570 ZSTD_parameters params,
2571 unsigned long long pledgedSrcSize);
2572
2573/*! ZSTD_initCStream_usingCDict() :
2574 * This function is DEPRECATED, and equivalent to:
2575 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
2576 * ZSTD_CCtx_refCDict(zcs, cdict);
2577 *
2578 * note : cdict will just be referenced, and must outlive compression session
2579 * This prototype will generate compilation warnings.
2580 */
2581ZSTD_DEPRECATED("use ZSTD_CCtx_reset and ZSTD_CCtx_refCDict, see zstd.h for detailed instructions")
2582ZSTDLIB_STATIC_API
2583size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict);
2584
2585/*! ZSTD_initCStream_usingCDict_advanced() :
2586 * This function is DEPRECATED, and is equivalent to:
2587 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
2588 * ZSTD_CCtx_setFParams(zcs, fParams);
2589 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
2590 * ZSTD_CCtx_refCDict(zcs, cdict);
2591 *
2592 * same as ZSTD_initCStream_usingCDict(), with control over frame parameters.
2593 * pledgedSrcSize must be correct. If srcSize is not known at init time, use
2594 * value ZSTD_CONTENTSIZE_UNKNOWN.
2595 * This prototype will generate compilation warnings.
2596 */
2597ZSTD_DEPRECATED("use ZSTD_CCtx_reset and ZSTD_CCtx_refCDict, see zstd.h for detailed instructions")
2598ZSTDLIB_STATIC_API
2599size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs,
2600 const ZSTD_CDict* cdict,
2601 ZSTD_frameParameters fParams,
2602 unsigned long long pledgedSrcSize);
2603
2604/*! ZSTD_resetCStream() :
2605 * This function is DEPRECATED, and is equivalent to:
2606 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
2607 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
2608 * Note: ZSTD_resetCStream() interprets pledgedSrcSize == 0 as ZSTD_CONTENTSIZE_UNKNOWN, but
2609 * ZSTD_CCtx_setPledgedSrcSize() does not do the same, so ZSTD_CONTENTSIZE_UNKNOWN must be
2610 * explicitly specified.
2611 *
2612 * start a new frame, using same parameters from previous frame.
f535537f 2613 * This is typically useful to skip dictionary loading stage, since it will reuse it in-place.
648db22b 2614 * Note that zcs must be init at least once before using ZSTD_resetCStream().
2615 * If pledgedSrcSize is not known at reset time, use macro ZSTD_CONTENTSIZE_UNKNOWN.
2616 * If pledgedSrcSize > 0, its value must be correct, as it will be written in header, and controlled at the end.
2617 * For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs,
2618 * but it will change to mean "empty" in future version, so use macro ZSTD_CONTENTSIZE_UNKNOWN instead.
2619 * @return : 0, or an error code (which can be tested using ZSTD_isError())
2620 * This prototype will generate compilation warnings.
2621 */
2622ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions")
2623ZSTDLIB_STATIC_API
2624size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize);
2625
2626
2627typedef struct {
2628 unsigned long long ingested; /* nb input bytes read and buffered */
2629 unsigned long long consumed; /* nb input bytes actually compressed */
2630 unsigned long long produced; /* nb of compressed bytes generated and buffered */
2631 unsigned long long flushed; /* nb of compressed bytes flushed : not provided; can be tracked from caller side */
2632 unsigned currentJobID; /* MT only : latest started job nb */
2633 unsigned nbActiveWorkers; /* MT only : nb of workers actively compressing at probe time */
2634} ZSTD_frameProgression;
2635
2636/* ZSTD_getFrameProgression() :
2637 * tells how much data has been ingested (read from input)
2638 * consumed (input actually compressed) and produced (output) for current frame.
2639 * Note : (ingested - consumed) is amount of input data buffered internally, not yet compressed.
2640 * Aggregates progression inside active worker threads.
2641 */
2642ZSTDLIB_STATIC_API ZSTD_frameProgression ZSTD_getFrameProgression(const ZSTD_CCtx* cctx);
2643
2644/*! ZSTD_toFlushNow() :
2645 * Tell how many bytes are ready to be flushed immediately.
2646 * Useful for multithreading scenarios (nbWorkers >= 1).
2647 * Probe the oldest active job, defined as oldest job not yet entirely flushed,
2648 * and check its output buffer.
2649 * @return : amount of data stored in oldest job and ready to be flushed immediately.
2650 * if @return == 0, it means either :
2651 * + there is no active job (could be checked with ZSTD_frameProgression()), or
2652 * + oldest job is still actively compressing data,
2653 * but everything it has produced has also been flushed so far,
2654 * therefore flush speed is limited by production speed of oldest job
2655 * irrespective of the speed of concurrent (and newer) jobs.
2656 */
2657ZSTDLIB_STATIC_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx);
2658
2659
2660/*===== Advanced Streaming decompression functions =====*/
2661
2662/*!
2663 * This function is deprecated, and is equivalent to:
2664 *
2665 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
2666 * ZSTD_DCtx_loadDictionary(zds, dict, dictSize);
2667 *
2668 * note: no dictionary will be used if dict == NULL or dictSize < 8
2669 */
2670ZSTD_DEPRECATED("use ZSTD_DCtx_reset + ZSTD_DCtx_loadDictionary, see zstd.h for detailed instructions")
2671ZSTDLIB_STATIC_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize);
2672
2673/*!
2674 * This function is deprecated, and is equivalent to:
2675 *
2676 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
2677 * ZSTD_DCtx_refDDict(zds, ddict);
2678 *
2679 * note : ddict is referenced, it must outlive decompression session
2680 */
2681ZSTD_DEPRECATED("use ZSTD_DCtx_reset + ZSTD_DCtx_refDDict, see zstd.h for detailed instructions")
2682ZSTDLIB_STATIC_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict);
2683
2684/*!
2685 * This function is deprecated, and is equivalent to:
2686 *
2687 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
2688 *
f535537f 2689 * reuse decompression parameters from previous init; saves dictionary loading
648db22b 2690 */
2691ZSTD_DEPRECATED("use ZSTD_DCtx_reset, see zstd.h for detailed instructions")
2692ZSTDLIB_STATIC_API size_t ZSTD_resetDStream(ZSTD_DStream* zds);
2693
2694
2695/* ********************* BLOCK-LEVEL SEQUENCE PRODUCER API *********************
2696 *
2697 * *** OVERVIEW ***
2698 * The Block-Level Sequence Producer API allows users to provide their own custom
2699 * sequence producer which libzstd invokes to process each block. The produced list
2700 * of sequences (literals and matches) is then post-processed by libzstd to produce
2701 * valid compressed blocks.
2702 *
2703 * This block-level offload API is a more granular complement of the existing
2704 * frame-level offload API compressSequences() (introduced in v1.5.1). It offers
2705 * an easier migration story for applications already integrated with libzstd: the
2706 * user application continues to invoke the same compression functions
2707 * ZSTD_compress2() or ZSTD_compressStream2() as usual, and transparently benefits
2708 * from the specific advantages of the external sequence producer. For example,
2709 * the sequence producer could be tuned to take advantage of known characteristics
2710 * of the input, to offer better speed / ratio, or could leverage hardware
2711 * acceleration not available within libzstd itself.
2712 *
2713 * See contrib/externalSequenceProducer for an example program employing the
2714 * Block-Level Sequence Producer API.
2715 *
2716 * *** USAGE ***
2717 * The user is responsible for implementing a function of type
2718 * ZSTD_sequenceProducer_F. For each block, zstd will pass the following
2719 * arguments to the user-provided function:
2720 *
2721 * - sequenceProducerState: a pointer to a user-managed state for the sequence
2722 * producer.
2723 *
2724 * - outSeqs, outSeqsCapacity: an output buffer for the sequence producer.
2725 * outSeqsCapacity is guaranteed >= ZSTD_sequenceBound(srcSize). The memory
2726 * backing outSeqs is managed by the CCtx.
2727 *
2728 * - src, srcSize: an input buffer for the sequence producer to parse.
2729 * srcSize is guaranteed to be <= ZSTD_BLOCKSIZE_MAX.
2730 *
2731 * - dict, dictSize: a history buffer, which may be empty, which the sequence
2732 * producer may reference as it parses the src buffer. Currently, zstd will
2733 * always pass dictSize == 0 into external sequence producers, but this will
2734 * change in the future.
2735 *
2736 * - compressionLevel: a signed integer representing the zstd compression level
2737 * set by the user for the current operation. The sequence producer may choose
2738 * to use this information to change its compression strategy and speed/ratio
2739 * tradeoff. Note: the compression level does not reflect zstd parameters set
2740 * through the advanced API.
2741 *
2742 * - windowSize: a size_t representing the maximum allowed offset for external
2743 * sequences. Note that sequence offsets are sometimes allowed to exceed the
2744 * windowSize if a dictionary is present, see doc/zstd_compression_format.md
2745 * for details.
2746 *
2747 * The user-provided function shall return a size_t representing the number of
2748 * sequences written to outSeqs. This return value will be treated as an error
2749 * code if it is greater than outSeqsCapacity. The return value must be non-zero
2750 * if srcSize is non-zero. The ZSTD_SEQUENCE_PRODUCER_ERROR macro is provided
2751 * for convenience, but any value greater than outSeqsCapacity will be treated as
2752 * an error code.
2753 *
2754 * If the user-provided function does not return an error code, the sequences
2755 * written to outSeqs must be a valid parse of the src buffer. Data corruption may
2756 * occur if the parse is not valid. A parse is defined to be valid if the
2757 * following conditions hold:
2758 * - The sum of matchLengths and literalLengths must equal srcSize.
2759 * - All sequences in the parse, except for the final sequence, must have
2760 * matchLength >= ZSTD_MINMATCH_MIN. The final sequence must have
2761 * matchLength >= ZSTD_MINMATCH_MIN or matchLength == 0.
2762 * - All offsets must respect the windowSize parameter as specified in
2763 * doc/zstd_compression_format.md.
2764 * - If the final sequence has matchLength == 0, it must also have offset == 0.
2765 *
2766 * zstd will only validate these conditions (and fail compression if they do not
2767 * hold) if the ZSTD_c_validateSequences cParam is enabled. Note that sequence
2768 * validation has a performance cost.
2769 *
2770 * If the user-provided function returns an error, zstd will either fall back
2771 * to an internal sequence producer or fail the compression operation. The user can
2772 * choose between the two behaviors by setting the ZSTD_c_enableSeqProducerFallback
2773 * cParam. Fallback compression will follow any other cParam settings, such as
2774 * compression level, the same as in a normal compression operation.
2775 *
2776 * The user shall instruct zstd to use a particular ZSTD_sequenceProducer_F
2777 * function by calling
2778 * ZSTD_registerSequenceProducer(cctx,
2779 * sequenceProducerState,
2780 * sequenceProducer)
2781 * This setting will persist until the next parameter reset of the CCtx.
2782 *
2783 * The sequenceProducerState must be initialized by the user before calling
2784 * ZSTD_registerSequenceProducer(). The user is responsible for destroying the
2785 * sequenceProducerState.
2786 *
2787 * *** LIMITATIONS ***
2788 * This API is compatible with all zstd compression APIs which respect advanced parameters.
2789 * However, there are three limitations:
2790 *
2791 * First, the ZSTD_c_enableLongDistanceMatching cParam is not currently supported.
2792 * COMPRESSION WILL FAIL if it is enabled and the user tries to compress with a block-level
2793 * external sequence producer.
2794 * - Note that ZSTD_c_enableLongDistanceMatching is auto-enabled by default in some
2795 * cases (see its documentation for details). Users must explicitly set
2796 * ZSTD_c_enableLongDistanceMatching to ZSTD_ps_disable in such cases if an external
2797 * sequence producer is registered.
2798 * - As of this writing, ZSTD_c_enableLongDistanceMatching is disabled by default
2799 * whenever ZSTD_c_windowLog < 128MB, but that's subject to change. Users should
2800 * check the docs on ZSTD_c_enableLongDistanceMatching whenever the Block-Level Sequence
2801 * Producer API is used in conjunction with advanced settings (like ZSTD_c_windowLog).
2802 *
2803 * Second, history buffers are not currently supported. Concretely, zstd will always pass
2804 * dictSize == 0 to the external sequence producer (for now). This has two implications:
2805 * - Dictionaries are not currently supported. Compression will *not* fail if the user
2806 * references a dictionary, but the dictionary won't have any effect.
2807 * - Stream history is not currently supported. All advanced compression APIs, including
2808 * streaming APIs, work with external sequence producers, but each block is treated as
2809 * an independent chunk without history from previous blocks.
2810 *
2811 * Third, multi-threading within a single compression is not currently supported. In other words,
2812 * COMPRESSION WILL FAIL if ZSTD_c_nbWorkers > 0 and an external sequence producer is registered.
2813 * Multi-threading across compressions is fine: simply create one CCtx per thread.
2814 *
2815 * Long-term, we plan to overcome all three limitations. There is no technical blocker to
2816 * overcoming them. It is purely a question of engineering effort.
2817 */
2818
2819#define ZSTD_SEQUENCE_PRODUCER_ERROR ((size_t)(-1))
2820
f535537f 2821typedef size_t (*ZSTD_sequenceProducer_F) (
648db22b 2822 void* sequenceProducerState,
2823 ZSTD_Sequence* outSeqs, size_t outSeqsCapacity,
2824 const void* src, size_t srcSize,
2825 const void* dict, size_t dictSize,
2826 int compressionLevel,
2827 size_t windowSize
2828);
2829
2830/*! ZSTD_registerSequenceProducer() :
2831 * Instruct zstd to use a block-level external sequence producer function.
2832 *
2833 * The sequenceProducerState must be initialized by the caller, and the caller is
2834 * responsible for managing its lifetime. This parameter is sticky across
2835 * compressions. It will remain set until the user explicitly resets compression
2836 * parameters.
2837 *
2838 * Sequence producer registration is considered to be an "advanced parameter",
2839 * part of the "advanced API". This means it will only have an effect on compression
2840 * APIs which respect advanced parameters, such as compress2() and compressStream2().
2841 * Older compression APIs such as compressCCtx(), which predate the introduction of
2842 * "advanced parameters", will ignore any external sequence producer setting.
2843 *
2844 * The sequence producer can be "cleared" by registering a NULL function pointer. This
2845 * removes all limitations described above in the "LIMITATIONS" section of the API docs.
2846 *
2847 * The user is strongly encouraged to read the full API documentation (above) before
2848 * calling this function. */
2849ZSTDLIB_STATIC_API void
2850ZSTD_registerSequenceProducer(
2851 ZSTD_CCtx* cctx,
2852 void* sequenceProducerState,
f535537f 2853 ZSTD_sequenceProducer_F sequenceProducer
2854);
2855
2856/*! ZSTD_CCtxParams_registerSequenceProducer() :
2857 * Same as ZSTD_registerSequenceProducer(), but operates on ZSTD_CCtx_params.
2858 * This is used for accurate size estimation with ZSTD_estimateCCtxSize_usingCCtxParams(),
2859 * which is needed when creating a ZSTD_CCtx with ZSTD_initStaticCCtx().
2860 *
2861 * If you are using the external sequence producer API in a scenario where ZSTD_initStaticCCtx()
2862 * is required, then this function is for you. Otherwise, you probably don't need it.
2863 *
2864 * See tests/zstreamtest.c for example usage. */
2865ZSTDLIB_STATIC_API void
2866ZSTD_CCtxParams_registerSequenceProducer(
2867 ZSTD_CCtx_params* params,
2868 void* sequenceProducerState,
2869 ZSTD_sequenceProducer_F sequenceProducer
648db22b 2870);
2871
2872
2873/*********************************************************************
2874* Buffer-less and synchronous inner streaming functions (DEPRECATED)
2875*
2876* This API is deprecated, and will be removed in a future version.
2877* It allows streaming (de)compression with user allocated buffers.
2878* However, it is hard to use, and not as well tested as the rest of
2879* our API.
2880*
2881* Please use the normal streaming API instead: ZSTD_compressStream2,
2882* and ZSTD_decompressStream.
2883* If there is functionality that you need, but it doesn't provide,
2884* please open an issue on our GitHub.
2885********************************************************************* */
2886
2887/**
2888 Buffer-less streaming compression (synchronous mode)
2889
2890 A ZSTD_CCtx object is required to track streaming operations.
2891 Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource.
f535537f 2892 ZSTD_CCtx object can be reused multiple times within successive compression operations.
648db22b 2893
2894 Start by initializing a context.
2895 Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary compression.
2896
2897 Then, consume your input using ZSTD_compressContinue().
2898 There are some important considerations to keep in mind when using this advanced function :
2899 - ZSTD_compressContinue() has no internal buffer. It uses externally provided buffers only.
2900 - Interface is synchronous : input is consumed entirely and produces 1+ compressed blocks.
2901 - Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario.
2902 Worst case evaluation is provided by ZSTD_compressBound().
2903 ZSTD_compressContinue() doesn't guarantee recover after a failed compression.
2904 - ZSTD_compressContinue() presumes prior input ***is still accessible and unmodified*** (up to maximum distance size, see WindowLog).
2905 It remembers all previous contiguous blocks, plus one separated memory segment (which can itself consists of multiple contiguous blocks)
2906 - ZSTD_compressContinue() detects that prior input has been overwritten when `src` buffer overlaps.
2907 In which case, it will "discard" the relevant memory section from its history.
2908
2909 Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum.
2910 It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame.
2911 Without last block mark, frames are considered unfinished (hence corrupted) by compliant decoders.
2912
f535537f 2913 `ZSTD_CCtx` object can be reused (ZSTD_compressBegin()) to compress again.
648db22b 2914*/
2915
2916/*===== Buffer-less streaming compression functions =====*/
2917ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.")
2918ZSTDLIB_STATIC_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel);
2919ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.")
2920ZSTDLIB_STATIC_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel);
2921ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.")
2922ZSTDLIB_STATIC_API size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); /**< note: fails if cdict==NULL */
2923
2924ZSTD_DEPRECATED("This function will likely be removed in a future release. It is misleading and has very limited utility.")
2925ZSTDLIB_STATIC_API
2926size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); /**< note: if pledgedSrcSize is not known, use ZSTD_CONTENTSIZE_UNKNOWN */
2927
2928ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.")
2929ZSTDLIB_STATIC_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
2930ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.")
2931ZSTDLIB_STATIC_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
2932
2933/* The ZSTD_compressBegin_advanced() and ZSTD_compressBegin_usingCDict_advanced() are now DEPRECATED and will generate a compiler warning */
2934ZSTD_DEPRECATED("use advanced API to access custom parameters")
2935ZSTDLIB_STATIC_API
2936size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize : If srcSize is not known at init time, use ZSTD_CONTENTSIZE_UNKNOWN */
2937ZSTD_DEPRECATED("use advanced API to access custom parameters")
2938ZSTDLIB_STATIC_API
2939size_t ZSTD_compressBegin_usingCDict_advanced(ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict, ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize); /* compression parameters are already set within cdict. pledgedSrcSize must be correct. If srcSize is not known, use macro ZSTD_CONTENTSIZE_UNKNOWN */
2940/**
2941 Buffer-less streaming decompression (synchronous mode)
2942
2943 A ZSTD_DCtx object is required to track streaming operations.
2944 Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
f535537f 2945 A ZSTD_DCtx object can be reused multiple times.
648db22b 2946
2947 First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader().
2948 Frame header is extracted from the beginning of compressed frame, so providing only the frame's beginning is enough.
2949 Data fragment must be large enough to ensure successful decoding.
2950 `ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough.
2951 result : 0 : successful decoding, the `ZSTD_frameHeader` structure is correctly filled.
2952 >0 : `srcSize` is too small, please provide at least result bytes on next attempt.
2953 errorCode, which can be tested using ZSTD_isError().
2954
2955 It fills a ZSTD_frameHeader structure with important information to correctly decode the frame,
2956 such as the dictionary ID, content size, or maximum back-reference distance (`windowSize`).
2957 Note that these values could be wrong, either because of data corruption, or because a 3rd party deliberately spoofs false information.
2958 As a consequence, check that values remain within valid application range.
2959 For example, do not allocate memory blindly, check that `windowSize` is within expectation.
2960 Each application can set its own limits, depending on local restrictions.
2961 For extended interoperability, it is recommended to support `windowSize` of at least 8 MB.
2962
2963 ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize` bytes.
2964 ZSTD_decompressContinue() is very sensitive to contiguity,
2965 if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place,
2966 or that previous contiguous segment is large enough to properly handle maximum back-reference distance.
2967 There are multiple ways to guarantee this condition.
2968
2969 The most memory efficient way is to use a round buffer of sufficient size.
2970 Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(),
2971 which can return an error code if required value is too large for current system (in 32-bits mode).
2972 In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one,
2973 up to the moment there is not enough room left in the buffer to guarantee decoding another full block,
2974 which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`.
2975 At which point, decoding can resume from the beginning of the buffer.
2976 Note that already decoded data stored in the buffer should be flushed before being overwritten.
2977
2978 There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory.
2979
2980 Finally, if you control the compression process, you can also ignore all buffer size rules,
2981 as long as the encoder and decoder progress in "lock-step",
2982 aka use exactly the same buffer sizes, break contiguity at the same place, etc.
2983
2984 Once buffers are setup, start decompression, with ZSTD_decompressBegin().
2985 If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict().
2986
2987 Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively.
2988 ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue().
2989 ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail.
2990
2991 result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity).
2992 It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item.
2993 It can also be an error code, which can be tested with ZSTD_isError().
2994
2995 A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero.
2996 Context can then be reset to start a new decompression.
2997
2998 Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType().
2999 This information is not required to properly decode a frame.
3000
3001 == Special case : skippable frames ==
3002
3003 Skippable frames allow integration of user-defined data into a flow of concatenated frames.
3004 Skippable frames will be ignored (skipped) by decompressor.
3005 The format of skippable frames is as follows :
3006 a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F
3007 b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits
3008 c) Frame Content - any content (User Data) of length equal to Frame Size
3009 For skippable frames ZSTD_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame.
3010 For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content.
3011*/
3012
3013/*===== Buffer-less streaming decompression functions =====*/
3014
3015ZSTDLIB_STATIC_API size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize); /**< when frame content size is not known, pass in frameContentSize == ZSTD_CONTENTSIZE_UNKNOWN */
3016
3017ZSTDLIB_STATIC_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx);
3018ZSTDLIB_STATIC_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
3019ZSTDLIB_STATIC_API size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict);
3020
3021ZSTDLIB_STATIC_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx);
3022ZSTDLIB_STATIC_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
3023
3024/* misc */
3025ZSTD_DEPRECATED("This function will likely be removed in the next minor release. It is misleading and has very limited utility.")
3026ZSTDLIB_STATIC_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx);
3027typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e;
3028ZSTDLIB_STATIC_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
3029
3030
3031
3032
3033/* ========================================= */
3034/** Block level API (DEPRECATED) */
3035/* ========================================= */
3036
3037/*!
3038
3039 This API is deprecated in favor of the regular compression API.
3040 You can get the frame header down to 2 bytes by setting:
3041 - ZSTD_c_format = ZSTD_f_zstd1_magicless
3042 - ZSTD_c_contentSizeFlag = 0
3043 - ZSTD_c_checksumFlag = 0
3044 - ZSTD_c_dictIDFlag = 0
3045
3046 This API is not as well tested as our normal API, so we recommend not using it.
3047 We will be removing it in a future version. If the normal API doesn't provide
3048 the functionality you need, please open a GitHub issue.
3049
3050 Block functions produce and decode raw zstd blocks, without frame metadata.
3051 Frame metadata cost is typically ~12 bytes, which can be non-negligible for very small blocks (< 100 bytes).
3052 But users will have to take in charge needed metadata to regenerate data, such as compressed and content sizes.
3053
3054 A few rules to respect :
3055 - Compressing and decompressing require a context structure
3056 + Use ZSTD_createCCtx() and ZSTD_createDCtx()
3057 - It is necessary to init context before starting
3058 + compression : any ZSTD_compressBegin*() variant, including with dictionary
3059 + decompression : any ZSTD_decompressBegin*() variant, including with dictionary
3060 - Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB
3061 + If input is larger than a block size, it's necessary to split input data into multiple blocks
3062 + For inputs larger than a single block, consider using regular ZSTD_compress() instead.
3063 Frame metadata is not that costly, and quickly becomes negligible as source size grows larger than a block.
3064 - When a block is considered not compressible enough, ZSTD_compressBlock() result will be 0 (zero) !
3065 ===> In which case, nothing is produced into `dst` !
3066 + User __must__ test for such outcome and deal directly with uncompressed data
3067 + A block cannot be declared incompressible if ZSTD_compressBlock() return value was != 0.
3068 Doing so would mess up with statistics history, leading to potential data corruption.
3069 + ZSTD_decompressBlock() _doesn't accept uncompressed data as input_ !!
3070 + In case of multiple successive blocks, should some of them be uncompressed,
3071 decoder must be informed of their existence in order to follow proper history.
3072 Use ZSTD_insertBlock() for such a case.
3073*/
3074
3075/*===== Raw zstd block functions =====*/
3076ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.")
3077ZSTDLIB_STATIC_API size_t ZSTD_getBlockSize (const ZSTD_CCtx* cctx);
3078ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.")
3079ZSTDLIB_STATIC_API size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
3080ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.")
3081ZSTDLIB_STATIC_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
3082ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.")
3083ZSTDLIB_STATIC_API size_t ZSTD_insertBlock (ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize); /**< insert uncompressed block into `dctx` history. Useful for multi-blocks decompression. */
3084
3085#endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */
3086
3087#if defined (__cplusplus)
3088}
3089#endif
ARM optimized PCSX fork