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comparison CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/include/zstd.h @ 69:33d812a61356
planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d
author | jpayne |
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date | Tue, 18 Mar 2025 17:55:14 -0400 |
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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) | |
11 extern "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 | |
109 #define ZSTD_VERSION_RELEASE 6 | |
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). */ | |
114 ZSTDLIB_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+. */ | |
123 ZSTDLIB_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()). */ | |
155 ZSTDLIB_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()). */ | |
165 ZSTDLIB_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) | |
193 ZSTDLIB_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. */ | |
201 ZSTD_DEPRECATED("Replaced by ZSTD_getFrameContentSize") | |
202 ZSTDLIB_API | |
203 unsigned 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 */ | |
211 ZSTDLIB_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 */ | |
231 #define ZSTD_MAX_INPUT_SIZE ((sizeof(size_t)==8) ? 0xFF00FF00FF00FF00ULL : 0xFF00FF00U) | |
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 */ | |
233 ZSTDLIB_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 */ | |
239 ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */ | |
240 ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */ | |
241 ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed, requires v1.4.0+ */ | |
242 ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */ | |
243 ZSTDLIB_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, | |
252 * and reuse it for each successive compression operation. | |
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 */ | |
259 typedef struct ZSTD_CCtx_s ZSTD_CCtx; | |
260 ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void); | |
261 ZSTDLIB_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. | |
265 * Important : in order to mirror `ZSTD_compress()` behavior, | |
266 * this function compresses at the requested compression level, | |
267 * __ignoring any other advanced parameter__ . | |
268 * If any advanced parameter was set using the advanced API, | |
269 * they will all be reset. Only `compressionLevel` remains. | |
270 */ | |
271 ZSTDLIB_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, | |
279 * and reuse it for each successive compression operation. | |
280 * This will make workload friendlier for system's memory. | |
281 * Use one context per thread for parallel execution. */ | |
282 typedef struct ZSTD_DCtx_s ZSTD_DCtx; | |
283 ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void); | |
284 ZSTDLIB_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. | |
289 * Compatible with sticky parameters (see below). | |
290 */ | |
291 ZSTDLIB_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*()` ! | |
305 * __They do not apply to one-shot variants such as ZSTD_compressCCtx()__ . | |
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. | |
310 * In the future, we expect to remove API entry points from experimental which are redundant with this API. | |
311 */ | |
312 | |
313 | |
314 /* Compression strategies, listed from fastest to strongest */ | |
315 typedef 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 | |
328 typedef 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". */ | |
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 */ | |
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 | |
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, | |
505 /* was ZSTD_c_experimentalParam6=1003; is now ZSTD_c_targetCBlockSize */ | |
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 | |
521 typedef 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 */ | |
534 ZSTDLIB_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 */ | |
547 ZSTDLIB_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 */ | |
564 ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize); | |
565 | |
566 typedef 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 */ | |
586 ZSTDLIB_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. | |
590 * (note that this entry point doesn't even expose a compression level parameter). | |
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 */ | |
600 ZSTDLIB_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 | |
617 typedef 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 | |
634 * ZSTD_d_maxBlockSize | |
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, | |
642 ZSTD_d_experimentalParam5=1004, | |
643 ZSTD_d_experimentalParam6=1005 | |
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 */ | |
654 ZSTDLIB_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 */ | |
663 ZSTDLIB_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 */ | |
671 ZSTDLIB_API size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset); | |
672 | |
673 | |
674 /**************************** | |
675 * Streaming | |
676 ****************************/ | |
677 | |
678 typedef 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 | |
684 typedef 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. | |
698 * It is recommended to reuse ZSTD_CStream since it will play nicer with system's memory, by re-using already allocated memory. | |
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, | |
705 * it will reuse the same sticky parameters as previous compression session. | |
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 | |
753 typedef 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 =====*/ | |
756 ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void); | |
757 ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs); /* accept NULL pointer */ | |
758 | |
759 /*===== Streaming compression functions =====*/ | |
760 typedef 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. | |
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()) | |
799 */ | |
800 ZSTDLIB_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 */ | |
819 ZSTDLIB_API size_t ZSTD_CStreamInSize(void); /**< recommended size for input buffer */ | |
820 ZSTDLIB_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 */ | |
839 ZSTDLIB_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 */ | |
846 ZSTDLIB_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). */ | |
848 ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); | |
849 /*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_end). */ | |
850 ZSTDLIB_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. | |
858 * ZSTD_DStream objects can be reused multiple times. | |
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 | |
880 typedef 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 =====*/ | |
883 ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void); | |
884 ZSTDLIB_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 */ | |
896 ZSTDLIB_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. | |
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()`) | |
918 */ | |
919 ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input); | |
920 | |
921 ZSTDLIB_API size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */ | |
922 ZSTDLIB_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. */ | |
935 ZSTDLIB_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. */ | |
947 ZSTDLIB_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 **********************************/ | |
956 typedef 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. */ | |
970 ZSTDLIB_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. */ | |
976 ZSTDLIB_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) */ | |
983 ZSTDLIB_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 | |
989 typedef 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. */ | |
994 ZSTDLIB_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. */ | |
999 ZSTDLIB_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. */ | |
1004 ZSTDLIB_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. */ | |
1018 ZSTDLIB_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. */ | |
1024 ZSTDLIB_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. */ | |
1030 ZSTDLIB_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. */ | |
1042 ZSTDLIB_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(). | |
1050 * Dictionaries are sticky, they remain valid when same context is reused, | |
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 */ | |
1079 ZSTDLIB_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. */ | |
1093 ZSTDLIB_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. */ | |
1114 ZSTDLIB_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 */ | |
1132 ZSTDLIB_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 */ | |
1151 ZSTDLIB_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 */ | |
1169 ZSTDLIB_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. */ | |
1177 ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx); | |
1178 ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx); | |
1179 ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); | |
1180 ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); | |
1181 ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict); | |
1182 ZSTDLIB_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 */ | |
1268 #define ZSTD_TARGETCBLOCKSIZE_MIN 1340 /* suitable to fit into an ethernet / wifi / 4G transport frame */ | |
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 | |
1276 typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params; | |
1277 | |
1278 typedef 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 | |
1315 typedef 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 | |
1325 typedef 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 | |
1331 typedef struct { | |
1332 ZSTD_compressionParameters cParams; | |
1333 ZSTD_frameParameters fParams; | |
1334 } ZSTD_parameters; | |
1335 | |
1336 typedef 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 | |
1342 typedef 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 | |
1347 typedef 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 | |
1354 typedef enum { | |
1355 /* Note: this enum controls ZSTD_d_forceIgnoreChecksum */ | |
1356 ZSTD_d_validateChecksum = 0, | |
1357 ZSTD_d_ignoreChecksum = 1 | |
1358 } ZSTD_forceIgnoreChecksum_e; | |
1359 | |
1360 typedef enum { | |
1361 /* Note: this enum controls ZSTD_d_refMultipleDDicts */ | |
1362 ZSTD_rmd_refSingleDDict = 0, | |
1363 ZSTD_rmd_refMultipleDDicts = 1 | |
1364 } ZSTD_refMultipleDDicts_e; | |
1365 | |
1366 typedef 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 | |
1405 typedef 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 | |
1414 typedef 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. */ | |
1449 ZSTDLIB_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 */ | |
1464 ZSTDLIB_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) */ | |
1470 ZSTDLIB_STATIC_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize); | |
1471 | |
1472 typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e; | |
1473 typedef 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() */ | |
1490 ZSTDLIB_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) */ | |
1494 ZSTDLIB_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 */ | |
1519 ZSTDLIB_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 | |
1541 typedef 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 */ | |
1553 ZSTDLIB_STATIC_API size_t ZSTD_sequenceBound(size_t srcSize); | |
1554 | |
1555 /*! ZSTD_generateSequences() : | |
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 * | |
1563 * Generate sequences using ZSTD_compress2(), given a source buffer. | |
1564 * | |
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 * | |
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 * | |
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(). | |
1582 */ | |
1583 ZSTD_DEPRECATED("For debugging only, will be replaced by ZSTD_extractSequences()") | |
1584 ZSTDLIB_STATIC_API size_t | |
1585 ZSTD_generateSequences(ZSTD_CCtx* zc, | |
1586 ZSTD_Sequence* outSeqs, size_t outSeqsSize, | |
1587 const void* src, size_t srcSize); | |
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 */ | |
1600 ZSTDLIB_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 */ | |
1632 ZSTDLIB_STATIC_API size_t | |
1633 ZSTD_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 */ | |
1651 ZSTDLIB_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 */ | |
1665 ZSTDLIB_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 */ | |
1671 ZSTDLIB_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. | |
1682 * This is useful in combination with ZSTD_initStatic(), | |
1683 * which makes it possible to employ a static buffer for ZSTD_CCtx* state. | |
1684 * | |
1685 * ZSTD_estimateCCtxSize() will provide a memory budget large enough | |
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. | |
1688 * The estimate will assume the input may be arbitrarily large, | |
1689 * which is the worst case. | |
1690 * | |
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 * | |
1695 * When srcSize can be bound by a known and rather "small" value, | |
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 | |
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. | |
1705 */ | |
1706 ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize(int maxCompressionLevel); | |
1707 ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams); | |
1708 ZSTDLIB_STATIC_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params); | |
1709 ZSTDLIB_STATIC_API size_t ZSTD_estimateDCtxSize(void); | |
1710 | |
1711 /*! ZSTD_estimateCStreamSize() : | |
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. | |
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. | |
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. | |
1724 * This information can be passed manually, using ZSTD_estimateDStreamSize, | |
1725 * or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame(); | |
1726 * Any frame requesting a window size larger than max specified one will be rejected. | |
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 | |
1730 */ | |
1731 ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize(int maxCompressionLevel); | |
1732 ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams); | |
1733 ZSTDLIB_STATIC_API size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params); | |
1734 ZSTDLIB_STATIC_API size_t ZSTD_estimateDStreamSize(size_t maxWindowSize); | |
1735 ZSTDLIB_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 */ | |
1742 ZSTDLIB_STATIC_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel); | |
1743 ZSTDLIB_STATIC_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod); | |
1744 ZSTDLIB_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 */ | |
1767 ZSTDLIB_STATIC_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize); | |
1768 ZSTDLIB_STATIC_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticCCtx() */ | |
1769 | |
1770 ZSTDLIB_STATIC_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize); | |
1771 ZSTDLIB_STATIC_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticDCtx() */ | |
1772 | |
1773 ZSTDLIB_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 | |
1780 ZSTDLIB_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 */ | |
1792 typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size); | |
1793 typedef void (*ZSTD_freeFunction) (void* opaque, void* address); | |
1794 typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem; | |
1795 static | |
1796 #ifdef __GNUC__ | |
1797 __attribute__((__unused__)) | |
1798 #endif | |
1799 ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; /**< this constant defers to stdlib's functions */ | |
1800 | |
1801 ZSTDLIB_STATIC_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem); | |
1802 ZSTDLIB_STATIC_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem); | |
1803 ZSTDLIB_STATIC_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem); | |
1804 ZSTDLIB_STATIC_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem); | |
1805 | |
1806 ZSTDLIB_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 */ | |
1822 typedef struct POOL_ctx_s ZSTD_threadPool; | |
1823 ZSTDLIB_STATIC_API ZSTD_threadPool* ZSTD_createThreadPool(size_t numThreads); | |
1824 ZSTDLIB_STATIC_API void ZSTD_freeThreadPool (ZSTD_threadPool* pool); /* accept NULL pointer */ | |
1825 ZSTDLIB_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 */ | |
1831 ZSTDLIB_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 | |
1838 ZSTDLIB_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 */ | |
1855 ZSTDLIB_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 */ | |
1860 ZSTDLIB_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 */ | |
1865 ZSTDLIB_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()) */ | |
1870 ZSTDLIB_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) */ | |
1878 ZSTDLIB_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 */ | |
1887 ZSTDLIB_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 */ | |
1893 ZSTDLIB_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 */ | |
1899 ZSTDLIB_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. */ | |
1905 ZSTD_DEPRECATED("use ZSTD_compress2") | |
1906 ZSTDLIB_STATIC_API | |
1907 size_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. */ | |
1917 ZSTD_DEPRECATED("use ZSTD_compress2 with ZSTD_CCtx_loadDictionary") | |
1918 ZSTDLIB_STATIC_API | |
1919 size_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` */ | |
1929 ZSTDLIB_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 ?) */ | |
1935 ZSTDLIB_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 ?) */ | |
1940 ZSTDLIB_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 | |
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 */ | |
2255 ZSTDLIB_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 */ | |
2275 ZSTDLIB_STATIC_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void); | |
2276 ZSTDLIB_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 */ | |
2281 ZSTDLIB_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 */ | |
2287 ZSTDLIB_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 */ | |
2293 ZSTDLIB_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 */ | |
2303 ZSTDLIB_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 */ | |
2310 ZSTDLIB_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 */ | |
2319 ZSTDLIB_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 */ | |
2328 ZSTDLIB_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. */ | |
2344 ZSTDLIB_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 */ | |
2351 ZSTDLIB_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. */ | |
2358 ZSTDLIB_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 ?). */ | |
2365 ZSTDLIB_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 ?) */ | |
2370 ZSTDLIB_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 */ | |
2379 ZSTDLIB_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 */ | |
2386 ZSTDLIB_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 | |
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 | |
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()). */ | |
2493 ZSTD_DEPRECATED("use ZSTD_DCtx_setParameter() instead") | |
2494 ZSTDLIB_STATIC_API | |
2495 size_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 */ | |
2503 ZSTDLIB_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 */ | |
2530 ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions") | |
2531 ZSTDLIB_STATIC_API | |
2532 size_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 */ | |
2548 ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions") | |
2549 ZSTDLIB_STATIC_API | |
2550 size_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 */ | |
2566 ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions") | |
2567 ZSTDLIB_STATIC_API | |
2568 size_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 */ | |
2581 ZSTD_DEPRECATED("use ZSTD_CCtx_reset and ZSTD_CCtx_refCDict, see zstd.h for detailed instructions") | |
2582 ZSTDLIB_STATIC_API | |
2583 size_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 */ | |
2597 ZSTD_DEPRECATED("use ZSTD_CCtx_reset and ZSTD_CCtx_refCDict, see zstd.h for detailed instructions") | |
2598 ZSTDLIB_STATIC_API | |
2599 size_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. | |
2613 * This is typically useful to skip dictionary loading stage, since it will reuse it in-place. | |
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 */ | |
2622 ZSTD_DEPRECATED("use ZSTD_CCtx_reset, see zstd.h for detailed instructions") | |
2623 ZSTDLIB_STATIC_API | |
2624 size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); | |
2625 | |
2626 | |
2627 typedef 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 */ | |
2642 ZSTDLIB_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 */ | |
2657 ZSTDLIB_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 */ | |
2670 ZSTD_DEPRECATED("use ZSTD_DCtx_reset + ZSTD_DCtx_loadDictionary, see zstd.h for detailed instructions") | |
2671 ZSTDLIB_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 */ | |
2681 ZSTD_DEPRECATED("use ZSTD_DCtx_reset + ZSTD_DCtx_refDDict, see zstd.h for detailed instructions") | |
2682 ZSTDLIB_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 * | |
2689 * reuse decompression parameters from previous init; saves dictionary loading | |
2690 */ | |
2691 ZSTD_DEPRECATED("use ZSTD_DCtx_reset, see zstd.h for detailed instructions") | |
2692 ZSTDLIB_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 | |
2821 typedef size_t (*ZSTD_sequenceProducer_F) ( | |
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. */ | |
2849 ZSTDLIB_STATIC_API void | |
2850 ZSTD_registerSequenceProducer( | |
2851 ZSTD_CCtx* cctx, | |
2852 void* sequenceProducerState, | |
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. */ | |
2865 ZSTDLIB_STATIC_API void | |
2866 ZSTD_CCtxParams_registerSequenceProducer( | |
2867 ZSTD_CCtx_params* params, | |
2868 void* sequenceProducerState, | |
2869 ZSTD_sequenceProducer_F sequenceProducer | |
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. | |
2892 ZSTD_CCtx object can be reused multiple times within successive compression operations. | |
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 | |
2913 `ZSTD_CCtx` object can be reused (ZSTD_compressBegin()) to compress again. | |
2914 */ | |
2915 | |
2916 /*===== Buffer-less streaming compression functions =====*/ | |
2917 ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") | |
2918 ZSTDLIB_STATIC_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel); | |
2919 ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") | |
2920 ZSTDLIB_STATIC_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel); | |
2921 ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") | |
2922 ZSTDLIB_STATIC_API size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); /**< note: fails if cdict==NULL */ | |
2923 | |
2924 ZSTD_DEPRECATED("This function will likely be removed in a future release. It is misleading and has very limited utility.") | |
2925 ZSTDLIB_STATIC_API | |
2926 size_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 | |
2928 ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") | |
2929 ZSTDLIB_STATIC_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); | |
2930 ZSTD_DEPRECATED("The buffer-less API is deprecated in favor of the normal streaming API. See docs.") | |
2931 ZSTDLIB_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 */ | |
2934 ZSTD_DEPRECATED("use advanced API to access custom parameters") | |
2935 ZSTDLIB_STATIC_API | |
2936 size_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 */ | |
2937 ZSTD_DEPRECATED("use advanced API to access custom parameters") | |
2938 ZSTDLIB_STATIC_API | |
2939 size_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. | |
2945 A ZSTD_DCtx object can be reused multiple times. | |
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 | |
3015 ZSTDLIB_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 | |
3017 ZSTDLIB_STATIC_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx); | |
3018 ZSTDLIB_STATIC_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); | |
3019 ZSTDLIB_STATIC_API size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); | |
3020 | |
3021 ZSTDLIB_STATIC_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx); | |
3022 ZSTDLIB_STATIC_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); | |
3023 | |
3024 /* misc */ | |
3025 ZSTD_DEPRECATED("This function will likely be removed in the next minor release. It is misleading and has very limited utility.") | |
3026 ZSTDLIB_STATIC_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx); | |
3027 typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e; | |
3028 ZSTDLIB_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 =====*/ | |
3076 ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.") | |
3077 ZSTDLIB_STATIC_API size_t ZSTD_getBlockSize (const ZSTD_CCtx* cctx); | |
3078 ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.") | |
3079 ZSTDLIB_STATIC_API size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); | |
3080 ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.") | |
3081 ZSTDLIB_STATIC_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); | |
3082 ZSTD_DEPRECATED("The block API is deprecated in favor of the normal compression API. See docs.") | |
3083 ZSTDLIB_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 |