1 /* 2 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 #if defined (__cplusplus) 11 extern "C" { 12 #endif 13 14 #ifndef ZSTD_H_235446 15 #define ZSTD_H_235446 16 17 /* ====== Dependency ======*/ 18 #include <stddef.h> /* size_t */ 19 20 21 /* ===== ZSTDLIB_API : control library symbols visibility ===== */ 22 #ifndef ZSTDLIB_VISIBILITY 23 # if defined(__GNUC__) && (__GNUC__ >= 4) 24 # define ZSTDLIB_VISIBILITY __attribute__ ((visibility ("default"))) 25 # else 26 # define ZSTDLIB_VISIBILITY 27 # endif 28 #endif 29 #if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) 30 # define ZSTDLIB_API __declspec(dllexport) ZSTDLIB_VISIBILITY 31 #elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) 32 # define ZSTDLIB_API __declspec(dllimport) ZSTDLIB_VISIBILITY /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/ 33 #else 34 # define ZSTDLIB_API ZSTDLIB_VISIBILITY 35 #endif 36 37 38 /******************************************************************************* 39 Introduction 40 41 zstd, short for Zstandard, is a fast lossless compression algorithm, targeting 42 real-time compression scenarios at zlib-level and better compression ratios. 43 The zstd compression library provides in-memory compression and decompression 44 functions. 45 46 The library supports regular compression levels from 1 up to ZSTD_maxCLevel(), 47 which is currently 22. Levels >= 20, labeled `--ultra`, should be used with 48 caution, as they require more memory. The library also offers negative 49 compression levels, which extend the range of speed vs. ratio preferences. 50 The lower the level, the faster the speed (at the cost of compression). 51 52 Compression can be done in: 53 - a single step (described as Simple API) 54 - a single step, reusing a context (described as Explicit context) 55 - unbounded multiple steps (described as Streaming compression) 56 57 The compression ratio achievable on small data can be highly improved using 58 a dictionary. Dictionary compression can be performed in: 59 - a single step (described as Simple dictionary API) 60 - a single step, reusing a dictionary (described as Bulk-processing 61 dictionary API) 62 63 Advanced experimental functions can be accessed using 64 `#define ZSTD_STATIC_LINKING_ONLY` before including zstd.h. 65 66 Advanced experimental APIs should never be used with a dynamically-linked 67 library. They are not "stable"; their definitions or signatures may change in 68 the future. Only static linking is allowed. 69 *******************************************************************************/ 70 71 /*------ Version ------*/ 72 #define ZSTD_VERSION_MAJOR 1 73 #define ZSTD_VERSION_MINOR 4 74 #define ZSTD_VERSION_RELEASE 0 75 76 #define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE) 77 ZSTDLIB_API unsigned ZSTD_versionNumber(void); /**< to check runtime library version */ 78 79 #define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE 80 #define ZSTD_QUOTE(str) #str 81 #define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str) 82 #define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION) 83 ZSTDLIB_API const char* ZSTD_versionString(void); /* requires v1.3.0+ */ 84 85 /*************************************** 86 * Default constant 87 ***************************************/ 88 #ifndef ZSTD_CLEVEL_DEFAULT 89 # define ZSTD_CLEVEL_DEFAULT 3 90 #endif 91 92 /*************************************** 93 * Constants 94 ***************************************/ 95 96 /* All magic numbers are supposed read/written to/from files/memory using little-endian convention */ 97 #define ZSTD_MAGICNUMBER 0xFD2FB528 /* valid since v0.8.0 */ 98 #define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* valid since v0.7.0 */ 99 #define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50 /* all 16 values, from 0x184D2A50 to 0x184D2A5F, signal the beginning of a skippable frame */ 100 #define ZSTD_MAGIC_SKIPPABLE_MASK 0xFFFFFFF0 101 102 #define ZSTD_BLOCKSIZELOG_MAX 17 103 #define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX) 104 105 106 107 /*************************************** 108 * Simple API 109 ***************************************/ 110 /*! ZSTD_compress() : 111 * Compresses `src` content as a single zstd compressed frame into already allocated `dst`. 112 * Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`. 113 * @return : compressed size written into `dst` (<= `dstCapacity), 114 * or an error code if it fails (which can be tested using ZSTD_isError()). */ 115 ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity, 116 const void* src, size_t srcSize, 117 int compressionLevel); 118 119 /*! ZSTD_decompress() : 120 * `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames. 121 * `dstCapacity` is an upper bound of originalSize to regenerate. 122 * If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data. 123 * @return : the number of bytes decompressed into `dst` (<= `dstCapacity`), 124 * or an errorCode if it fails (which can be tested using ZSTD_isError()). */ 125 ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity, 126 const void* src, size_t compressedSize); 127 128 /*! ZSTD_getFrameContentSize() : requires v1.3.0+ 129 * `src` should point to the start of a ZSTD encoded frame. 130 * `srcSize` must be at least as large as the frame header. 131 * hint : any size >= `ZSTD_frameHeaderSize_max` is large enough. 132 * @return : - decompressed size of `src` frame content, if known 133 * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined 134 * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) 135 * note 1 : a 0 return value means the frame is valid but "empty". 136 * note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode. 137 * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. 138 * In which case, it's necessary to use streaming mode to decompress data. 139 * Optionally, application can rely on some implicit limit, 140 * as ZSTD_decompress() only needs an upper bound of decompressed size. 141 * (For example, data could be necessarily cut into blocks <= 16 KB). 142 * note 3 : decompressed size is always present when compression is completed using single-pass functions, 143 * such as ZSTD_compress(), ZSTD_compressCCtx() ZSTD_compress_usingDict() or ZSTD_compress_usingCDict(). 144 * note 4 : decompressed size can be very large (64-bits value), 145 * potentially larger than what local system can handle as a single memory segment. 146 * In which case, it's necessary to use streaming mode to decompress data. 147 * note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified. 148 * Always ensure return value fits within application's authorized limits. 149 * Each application can set its own limits. 150 * note 6 : This function replaces ZSTD_getDecompressedSize() */ 151 #define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1) 152 #define ZSTD_CONTENTSIZE_ERROR (0ULL - 2) 153 ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize); 154 155 /*! ZSTD_getDecompressedSize() : 156 * NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize(). 157 * Both functions work the same way, but ZSTD_getDecompressedSize() blends 158 * "empty", "unknown" and "error" results to the same return value (0), 159 * while ZSTD_getFrameContentSize() gives them separate return values. 160 * @return : decompressed size of `src` frame content _if known and not empty_, 0 otherwise. */ 161 ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize); 162 163 /*! ZSTD_findFrameCompressedSize() : 164 * `src` should point to the start of a ZSTD frame or skippable frame. 165 * `srcSize` must be >= first frame size 166 * @return : the compressed size of the first frame starting at `src`, 167 * suitable to pass as `srcSize` to `ZSTD_decompress` or similar, 168 * or an error code if input is invalid */ 169 ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize); 170 171 172 /*====== Helper functions ======*/ 173 #define ZSTD_COMPRESSBOUND(srcSize) ((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 */ 174 ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case single-pass scenario */ 175 ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */ 176 ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */ 177 ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed */ 178 ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */ 179 180 181 /*************************************** 182 * Explicit context 183 ***************************************/ 184 /*= Compression context 185 * When compressing many times, 186 * it is recommended to allocate a context just once, and re-use it for each successive compression operation. 187 * This will make workload friendlier for system's memory. 188 * Use one context per thread for parallel execution in multi-threaded environments. */ 189 typedef struct ZSTD_CCtx_s ZSTD_CCtx; 190 ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void); 191 ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); 192 193 /*! ZSTD_compressCCtx() : 194 * Same as ZSTD_compress(), using an explicit ZSTD_CCtx 195 * The function will compress at requested compression level, 196 * ignoring any other parameter */ 197 ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* cctx, 198 void* dst, size_t dstCapacity, 199 const void* src, size_t srcSize, 200 int compressionLevel); 201 202 /*= Decompression context 203 * When decompressing many times, 204 * it is recommended to allocate a context only once, 205 * and re-use it for each successive compression operation. 206 * This will make workload friendlier for system's memory. 207 * Use one context per thread for parallel execution. */ 208 typedef struct ZSTD_DCtx_s ZSTD_DCtx; 209 ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void); 210 ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx); 211 212 /*! ZSTD_decompressDCtx() : 213 * Same as ZSTD_decompress(), 214 * requires an allocated ZSTD_DCtx. 215 * Compatible with sticky parameters. 216 */ 217 ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, 218 void* dst, size_t dstCapacity, 219 const void* src, size_t srcSize); 220 221 222 /*************************************** 223 * Advanced compression API 224 ***************************************/ 225 226 /* API design : 227 * Parameters are pushed one by one into an existing context, 228 * using ZSTD_CCtx_set*() functions. 229 * Pushed parameters are sticky : they are valid for next compressed frame, and any subsequent frame. 230 * "sticky" parameters are applicable to `ZSTD_compress2()` and `ZSTD_compressStream*()` ! 231 * They do not apply to "simple" one-shot variants such as ZSTD_compressCCtx() 232 * 233 * It's possible to reset all parameters to "default" using ZSTD_CCtx_reset(). 234 * 235 * This API supercedes all other "advanced" API entry points in the experimental section. 236 * In the future, we expect to remove from experimental API entry points which are redundant with this API. 237 */ 238 239 240 /* Compression strategies, listed from fastest to strongest */ 241 typedef enum { ZSTD_fast=1, 242 ZSTD_dfast=2, 243 ZSTD_greedy=3, 244 ZSTD_lazy=4, 245 ZSTD_lazy2=5, 246 ZSTD_btlazy2=6, 247 ZSTD_btopt=7, 248 ZSTD_btultra=8, 249 ZSTD_btultra2=9 250 /* note : new strategies _might_ be added in the future. 251 Only the order (from fast to strong) is guaranteed */ 252 } ZSTD_strategy; 253 254 255 typedef enum { 256 257 /* compression parameters 258 * Note: When compressing with a ZSTD_CDict these parameters are superseded 259 * by the parameters used to construct the ZSTD_CDict. See ZSTD_CCtx_refCDict() 260 * for more info (superseded-by-cdict). */ 261 ZSTD_c_compressionLevel=100, /* Update all compression parameters according to pre-defined cLevel table 262 * Default level is ZSTD_CLEVEL_DEFAULT==3. 263 * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT. 264 * Note 1 : it's possible to pass a negative compression level. 265 * Note 2 : setting a level sets all default values of other compression parameters */ 266 ZSTD_c_windowLog=101, /* Maximum allowed back-reference distance, expressed as power of 2. 267 * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX. 268 * Special: value 0 means "use default windowLog". 269 * Note: Using a windowLog greater than ZSTD_WINDOWLOG_LIMIT_DEFAULT 270 * requires explicitly allowing such window size at decompression stage if using streaming. */ 271 ZSTD_c_hashLog=102, /* Size of the initial probe table, as a power of 2. 272 * Resulting memory usage is (1 << (hashLog+2)). 273 * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX. 274 * Larger tables improve compression ratio of strategies <= dFast, 275 * and improve speed of strategies > dFast. 276 * Special: value 0 means "use default hashLog". */ 277 ZSTD_c_chainLog=103, /* Size of the multi-probe search table, as a power of 2. 278 * Resulting memory usage is (1 << (chainLog+2)). 279 * Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX. 280 * Larger tables result in better and slower compression. 281 * This parameter is useless when using "fast" strategy. 282 * It's still useful when using "dfast" strategy, 283 * in which case it defines a secondary probe table. 284 * Special: value 0 means "use default chainLog". */ 285 ZSTD_c_searchLog=104, /* Number of search attempts, as a power of 2. 286 * More attempts result in better and slower compression. 287 * This parameter is useless when using "fast" and "dFast" strategies. 288 * Special: value 0 means "use default searchLog". */ 289 ZSTD_c_minMatch=105, /* Minimum size of searched matches. 290 * Note that Zstandard can still find matches of smaller size, 291 * it just tweaks its search algorithm to look for this size and larger. 292 * Larger values increase compression and decompression speed, but decrease ratio. 293 * Must be clamped between ZSTD_MINMATCH_MIN and ZSTD_MINMATCH_MAX. 294 * Note that currently, for all strategies < btopt, effective minimum is 4. 295 * , for all strategies > fast, effective maximum is 6. 296 * Special: value 0 means "use default minMatchLength". */ 297 ZSTD_c_targetLength=106, /* Impact of this field depends on strategy. 298 * For strategies btopt, btultra & btultra2: 299 * Length of Match considered "good enough" to stop search. 300 * Larger values make compression stronger, and slower. 301 * For strategy fast: 302 * Distance between match sampling. 303 * Larger values make compression faster, and weaker. 304 * Special: value 0 means "use default targetLength". */ 305 ZSTD_c_strategy=107, /* See ZSTD_strategy enum definition. 306 * The higher the value of selected strategy, the more complex it is, 307 * resulting in stronger and slower compression. 308 * Special: value 0 means "use default strategy". */ 309 310 /* LDM mode parameters */ 311 ZSTD_c_enableLongDistanceMatching=160, /* Enable long distance matching. 312 * This parameter is designed to improve compression ratio 313 * for large inputs, by finding large matches at long distance. 314 * It increases memory usage and window size. 315 * Note: enabling this parameter increases default ZSTD_c_windowLog to 128 MB 316 * except when expressly set to a different value. */ 317 ZSTD_c_ldmHashLog=161, /* Size of the table for long distance matching, as a power of 2. 318 * Larger values increase memory usage and compression ratio, 319 * but decrease compression speed. 320 * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX 321 * default: windowlog - 7. 322 * Special: value 0 means "automatically determine hashlog". */ 323 ZSTD_c_ldmMinMatch=162, /* Minimum match size for long distance matcher. 324 * Larger/too small values usually decrease compression ratio. 325 * Must be clamped between ZSTD_LDM_MINMATCH_MIN and ZSTD_LDM_MINMATCH_MAX. 326 * Special: value 0 means "use default value" (default: 64). */ 327 ZSTD_c_ldmBucketSizeLog=163, /* Log size of each bucket in the LDM hash table for collision resolution. 328 * Larger values improve collision resolution but decrease compression speed. 329 * The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX. 330 * Special: value 0 means "use default value" (default: 3). */ 331 ZSTD_c_ldmHashRateLog=164, /* Frequency of inserting/looking up entries into the LDM hash table. 332 * Must be clamped between 0 and (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN). 333 * Default is MAX(0, (windowLog - ldmHashLog)), optimizing hash table usage. 334 * Larger values improve compression speed. 335 * Deviating far from default value will likely result in a compression ratio decrease. 336 * Special: value 0 means "automatically determine hashRateLog". */ 337 338 /* frame parameters */ 339 ZSTD_c_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1) 340 * Content size must be known at the beginning of compression. 341 * This is automatically the case when using ZSTD_compress2(), 342 * For streaming variants, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */ 343 ZSTD_c_checksumFlag=201, /* A 32-bits checksum of content is written at end of frame (default:0) */ 344 ZSTD_c_dictIDFlag=202, /* When applicable, dictionary's ID is written into frame header (default:1) */ 345 346 /* multi-threading parameters */ 347 /* These parameters are only useful if multi-threading is enabled (compiled with build macro ZSTD_MULTITHREAD). 348 * They return an error otherwise. */ 349 ZSTD_c_nbWorkers=400, /* Select how many threads will be spawned to compress in parallel. 350 * When nbWorkers >= 1, triggers asynchronous mode when used with ZSTD_compressStream*() : 351 * ZSTD_compressStream*() consumes input and flush output if possible, but immediately gives back control to caller, 352 * while compression work is performed in parallel, within worker threads. 353 * (note : a strong exception to this rule is when first invocation of ZSTD_compressStream2() sets ZSTD_e_end : 354 * in which case, ZSTD_compressStream2() delegates to ZSTD_compress2(), which is always a blocking call). 355 * More workers improve speed, but also increase memory usage. 356 * Default value is `0`, aka "single-threaded mode" : no worker is spawned, compression is performed inside Caller's thread, all invocations are blocking */ 357 ZSTD_c_jobSize=401, /* Size of a compression job. This value is enforced only when nbWorkers >= 1. 358 * Each compression job is completed in parallel, so this value can indirectly impact the nb of active threads. 359 * 0 means default, which is dynamically determined based on compression parameters. 360 * Job size must be a minimum of overlap size, or 1 MB, whichever is largest. 361 * The minimum size is automatically and transparently enforced */ 362 ZSTD_c_overlapLog=402, /* Control the overlap size, as a fraction of window size. 363 * The overlap size is an amount of data reloaded from previous job at the beginning of a new job. 364 * It helps preserve compression ratio, while each job is compressed in parallel. 365 * This value is enforced only when nbWorkers >= 1. 366 * Larger values increase compression ratio, but decrease speed. 367 * Possible values range from 0 to 9 : 368 * - 0 means "default" : value will be determined by the library, depending on strategy 369 * - 1 means "no overlap" 370 * - 9 means "full overlap", using a full window size. 371 * Each intermediate rank increases/decreases load size by a factor 2 : 372 * 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 373 * default value varies between 6 and 9, depending on strategy */ 374 375 /* note : additional experimental parameters are also available 376 * within the experimental section of the API. 377 * At the time of this writing, they include : 378 * ZSTD_c_rsyncable 379 * ZSTD_c_format 380 * ZSTD_c_forceMaxWindow 381 * ZSTD_c_forceAttachDict 382 * ZSTD_c_literalCompressionMode 383 * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. 384 * note : never ever use experimentalParam? names directly; 385 * also, the enums values themselves are unstable and can still change. 386 */ 387 ZSTD_c_experimentalParam1=500, 388 ZSTD_c_experimentalParam2=10, 389 ZSTD_c_experimentalParam3=1000, 390 ZSTD_c_experimentalParam4=1001, 391 ZSTD_c_experimentalParam5=1002, 392 } ZSTD_cParameter; 393 394 typedef struct { 395 size_t error; 396 int lowerBound; 397 int upperBound; 398 } ZSTD_bounds; 399 400 /*! ZSTD_cParam_getBounds() : 401 * All parameters must belong to an interval with lower and upper bounds, 402 * otherwise they will either trigger an error or be automatically clamped. 403 * @return : a structure, ZSTD_bounds, which contains 404 * - an error status field, which must be tested using ZSTD_isError() 405 * - lower and upper bounds, both inclusive 406 */ 407 ZSTDLIB_API ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter cParam); 408 409 /*! ZSTD_CCtx_setParameter() : 410 * Set one compression parameter, selected by enum ZSTD_cParameter. 411 * All parameters have valid bounds. Bounds can be queried using ZSTD_cParam_getBounds(). 412 * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). 413 * Setting a parameter is generally only possible during frame initialization (before starting compression). 414 * Exception : when using multi-threading mode (nbWorkers >= 1), 415 * the following parameters can be updated _during_ compression (within same frame): 416 * => compressionLevel, hashLog, chainLog, searchLog, minMatch, targetLength and strategy. 417 * new parameters will be active for next job only (after a flush()). 418 * @return : an error code (which can be tested using ZSTD_isError()). 419 */ 420 ZSTDLIB_API size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value); 421 422 /*! ZSTD_CCtx_setPledgedSrcSize() : 423 * Total input data size to be compressed as a single frame. 424 * Value will be written in frame header, unless if explicitly forbidden using ZSTD_c_contentSizeFlag. 425 * This value will also be controlled at end of frame, and trigger an error if not respected. 426 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 427 * Note 1 : pledgedSrcSize==0 actually means zero, aka an empty frame. 428 * In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN. 429 * ZSTD_CONTENTSIZE_UNKNOWN is default value for any new frame. 430 * Note 2 : pledgedSrcSize is only valid once, for the next frame. 431 * It's discarded at the end of the frame, and replaced by ZSTD_CONTENTSIZE_UNKNOWN. 432 * Note 3 : Whenever all input data is provided and consumed in a single round, 433 * for example with ZSTD_compress2(), 434 * or invoking immediately ZSTD_compressStream2(,,,ZSTD_e_end), 435 * this value is automatically overridden by srcSize instead. 436 */ 437 ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize); 438 439 typedef enum { 440 ZSTD_reset_session_only = 1, 441 ZSTD_reset_parameters = 2, 442 ZSTD_reset_session_and_parameters = 3 443 } ZSTD_ResetDirective; 444 445 /*! ZSTD_CCtx_reset() : 446 * There are 2 different things that can be reset, independently or jointly : 447 * - The session : will stop compressing current frame, and make CCtx ready to start a new one. 448 * Useful after an error, or to interrupt any ongoing compression. 449 * Any internal data not yet flushed is cancelled. 450 * Compression parameters and dictionary remain unchanged. 451 * They will be used to compress next frame. 452 * Resetting session never fails. 453 * - The parameters : changes all parameters back to "default". 454 * This removes any reference to any dictionary too. 455 * Parameters can only be changed between 2 sessions (i.e. no compression is currently ongoing) 456 * otherwise the reset fails, and function returns an error value (which can be tested using ZSTD_isError()) 457 * - Both : similar to resetting the session, followed by resetting parameters. 458 */ 459 ZSTDLIB_API size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset); 460 461 /*! ZSTD_compress2() : 462 * Behave the same as ZSTD_compressCCtx(), but compression parameters are set using the advanced API. 463 * ZSTD_compress2() always starts a new frame. 464 * Should cctx hold data from a previously unfinished frame, everything about it is forgotten. 465 * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() 466 * - The function is always blocking, returns when compression is completed. 467 * Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`. 468 * @return : compressed size written into `dst` (<= `dstCapacity), 469 * or an error code if it fails (which can be tested using ZSTD_isError()). 470 */ 471 ZSTDLIB_API size_t ZSTD_compress2( ZSTD_CCtx* cctx, 472 void* dst, size_t dstCapacity, 473 const void* src, size_t srcSize); 474 475 476 /*************************************** 477 * Advanced decompression API 478 ***************************************/ 479 480 /* The advanced API pushes parameters one by one into an existing DCtx context. 481 * Parameters are sticky, and remain valid for all following frames 482 * using the same DCtx context. 483 * It's possible to reset parameters to default values using ZSTD_DCtx_reset(). 484 * Note : This API is compatible with existing ZSTD_decompressDCtx() and ZSTD_decompressStream(). 485 * Therefore, no new decompression function is necessary. 486 */ 487 488 typedef enum { 489 490 ZSTD_d_windowLogMax=100, /* Select a size limit (in power of 2) beyond which 491 * the streaming API will refuse to allocate memory buffer 492 * in order to protect the host from unreasonable memory requirements. 493 * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. 494 * By default, a decompression context accepts window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT). 495 * Special: value 0 means "use default maximum windowLog". */ 496 497 /* note : additional experimental parameters are also available 498 * within the experimental section of the API. 499 * At the time of this writing, they include : 500 * ZSTD_c_format 501 * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. 502 * note : never ever use experimentalParam? names directly 503 */ 504 ZSTD_d_experimentalParam1=1000 505 506 } ZSTD_dParameter; 507 508 /*! ZSTD_dParam_getBounds() : 509 * All parameters must belong to an interval with lower and upper bounds, 510 * otherwise they will either trigger an error or be automatically clamped. 511 * @return : a structure, ZSTD_bounds, which contains 512 * - an error status field, which must be tested using ZSTD_isError() 513 * - both lower and upper bounds, inclusive 514 */ 515 ZSTDLIB_API ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam); 516 517 /*! ZSTD_DCtx_setParameter() : 518 * Set one compression parameter, selected by enum ZSTD_dParameter. 519 * All parameters have valid bounds. Bounds can be queried using ZSTD_dParam_getBounds(). 520 * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). 521 * Setting a parameter is only possible during frame initialization (before starting decompression). 522 * @return : 0, or an error code (which can be tested using ZSTD_isError()). 523 */ 524 ZSTDLIB_API size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int value); 525 526 /*! ZSTD_DCtx_reset() : 527 * Return a DCtx to clean state. 528 * Session and parameters can be reset jointly or separately. 529 * Parameters can only be reset when no active frame is being decompressed. 530 * @return : 0, or an error code, which can be tested with ZSTD_isError() 531 */ 532 ZSTDLIB_API size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset); 533 534 535 /**************************** 536 * Streaming 537 ****************************/ 538 539 typedef struct ZSTD_inBuffer_s { 540 const void* src; /**< start of input buffer */ 541 size_t size; /**< size of input buffer */ 542 size_t pos; /**< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */ 543 } ZSTD_inBuffer; 544 545 typedef struct ZSTD_outBuffer_s { 546 void* dst; /**< start of output buffer */ 547 size_t size; /**< size of output buffer */ 548 size_t pos; /**< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */ 549 } ZSTD_outBuffer; 550 551 552 553 /*-*********************************************************************** 554 * Streaming compression - HowTo 555 * 556 * A ZSTD_CStream object is required to track streaming operation. 557 * Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources. 558 * ZSTD_CStream objects can be reused multiple times on consecutive compression operations. 559 * It is recommended to re-use ZSTD_CStream since it will play nicer with system's memory, by re-using already allocated memory. 560 * 561 * For parallel execution, use one separate ZSTD_CStream per thread. 562 * 563 * note : since v1.3.0, ZSTD_CStream and ZSTD_CCtx are the same thing. 564 * 565 * Parameters are sticky : when starting a new compression on the same context, 566 * it will re-use the same sticky parameters as previous compression session. 567 * When in doubt, it's recommended to fully initialize the context before usage. 568 * Use ZSTD_CCtx_reset() to reset the context and ZSTD_CCtx_setParameter(), 569 * ZSTD_CCtx_setPledgedSrcSize(), or ZSTD_CCtx_loadDictionary() and friends to 570 * set more specific parameters, the pledged source size, or load a dictionary. 571 * 572 * Use ZSTD_compressStream2() with ZSTD_e_continue as many times as necessary to 573 * consume input stream. The function will automatically update both `pos` 574 * fields within `input` and `output`. 575 * Note that the function may not consume the entire input, for example, because 576 * the output buffer is already full, in which case `input.pos < input.size`. 577 * The caller must check if input has been entirely consumed. 578 * If not, the caller must make some room to receive more compressed data, 579 * and then present again remaining input data. 580 * note: ZSTD_e_continue is guaranteed to make some forward progress when called, 581 * but doesn't guarantee maximal forward progress. This is especially relevant 582 * when compressing with multiple threads. The call won't block if it can 583 * consume some input, but if it can't it will wait for some, but not all, 584 * output to be flushed. 585 * @return : provides a minimum amount of data remaining to be flushed from internal buffers 586 * or an error code, which can be tested using ZSTD_isError(). 587 * 588 * At any moment, it's possible to flush whatever data might remain stuck within internal buffer, 589 * using ZSTD_compressStream2() with ZSTD_e_flush. `output->pos` will be updated. 590 * Note that, if `output->size` is too small, a single invocation with ZSTD_e_flush might not be enough (return code > 0). 591 * In which case, make some room to receive more compressed data, and call again ZSTD_compressStream2() with ZSTD_e_flush. 592 * You must continue calling ZSTD_compressStream2() with ZSTD_e_flush until it returns 0, at which point you can change the 593 * operation. 594 * note: ZSTD_e_flush will flush as much output as possible, meaning when compressing with multiple threads, it will 595 * block until the flush is complete or the output buffer is full. 596 * @return : 0 if internal buffers are entirely flushed, 597 * >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), 598 * or an error code, which can be tested using ZSTD_isError(). 599 * 600 * Calling ZSTD_compressStream2() with ZSTD_e_end instructs to finish a frame. 601 * It will perform a flush and write frame epilogue. 602 * The epilogue is required for decoders to consider a frame completed. 603 * flush operation is the same, and follows same rules as calling ZSTD_compressStream2() with ZSTD_e_flush. 604 * You must continue calling ZSTD_compressStream2() with ZSTD_e_end until it returns 0, at which point you are free to 605 * start a new frame. 606 * note: ZSTD_e_end will flush as much output as possible, meaning when compressing with multiple threads, it will 607 * block until the flush is complete or the output buffer is full. 608 * @return : 0 if frame fully completed and fully flushed, 609 * >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), 610 * or an error code, which can be tested using ZSTD_isError(). 611 * 612 * *******************************************************************/ 613 614 typedef ZSTD_CCtx ZSTD_CStream; /**< CCtx and CStream are now effectively same object (>= v1.3.0) */ 615 /* Continue to distinguish them for compatibility with older versions <= v1.2.0 */ 616 /*===== ZSTD_CStream management functions =====*/ 617 ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void); 618 ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs); 619 620 /*===== Streaming compression functions =====*/ 621 typedef enum { 622 ZSTD_e_continue=0, /* collect more data, encoder decides when to output compressed result, for optimal compression ratio */ 623 ZSTD_e_flush=1, /* flush any data provided so far, 624 * it creates (at least) one new block, that can be decoded immediately on reception; 625 * frame will continue: any future data can still reference previously compressed data, improving compression. 626 * note : multithreaded compression will block to flush as much output as possible. */ 627 ZSTD_e_end=2 /* flush any remaining data _and_ close current frame. 628 * note that frame is only closed after compressed data is fully flushed (return value == 0). 629 * After that point, any additional data starts a new frame. 630 * note : each frame is independent (does not reference any content from previous frame). 631 : note : multithreaded compression will block to flush as much output as possible. */ 632 } ZSTD_EndDirective; 633 634 /*! ZSTD_compressStream2() : 635 * Behaves about the same as ZSTD_compressStream, with additional control on end directive. 636 * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() 637 * - Compression parameters cannot be changed once compression is started (save a list of exceptions in multi-threading mode) 638 * - output->pos must be <= dstCapacity, input->pos must be <= srcSize 639 * - output->pos and input->pos will be updated. They are guaranteed to remain below their respective limit. 640 * - When nbWorkers==0 (default), function is blocking : it completes its job before returning to caller. 641 * - When nbWorkers>=1, function is non-blocking : it just acquires a copy of input, and distributes jobs to internal worker threads, flush whatever is available, 642 * and then immediately returns, just indicating that there is some data remaining to be flushed. 643 * The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte. 644 * - 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. 645 * - @return provides a minimum amount of data remaining to be flushed from internal buffers 646 * or an error code, which can be tested using ZSTD_isError(). 647 * if @return != 0, flush is not fully completed, there is still some data left within internal buffers. 648 * This is useful for ZSTD_e_flush, since in this case more flushes are necessary to empty all buffers. 649 * For ZSTD_e_end, @return == 0 when internal buffers are fully flushed and frame is completed. 650 * - after a ZSTD_e_end directive, if internal buffer is not fully flushed (@return != 0), 651 * only ZSTD_e_end or ZSTD_e_flush operations are allowed. 652 * Before starting a new compression job, or changing compression parameters, 653 * it is required to fully flush internal buffers. 654 */ 655 ZSTDLIB_API size_t ZSTD_compressStream2( ZSTD_CCtx* cctx, 656 ZSTD_outBuffer* output, 657 ZSTD_inBuffer* input, 658 ZSTD_EndDirective endOp); 659 660 ZSTDLIB_API size_t ZSTD_CStreamInSize(void); /**< recommended size for input buffer */ 661 ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block in all circumstances. */ 662 663 /******************************************************************************* 664 * This is a legacy streaming API, and can be replaced by ZSTD_CCtx_reset() and 665 * ZSTD_compressStream2(). It is redundant, but is still fully supported. 666 * Advanced parameters and dictionary compression can only be used through the 667 * new API. 668 ******************************************************************************/ 669 670 /** 671 * Equivalent to: 672 * 673 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 674 * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any) 675 * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); 676 */ 677 ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel); 678 /** 679 * Alternative for ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue). 680 * NOTE: The return value is different. ZSTD_compressStream() returns a hint for 681 * the next read size (if non-zero and not an error). ZSTD_compressStream2() 682 * returns the number of bytes left to flush (if non-zero and not an error). 683 */ 684 ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input); 685 /** Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_flush). */ 686 ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); 687 /** Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_end). */ 688 ZSTDLIB_API size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); 689 690 691 /*-*************************************************************************** 692 * Streaming decompression - HowTo 693 * 694 * A ZSTD_DStream object is required to track streaming operations. 695 * Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources. 696 * ZSTD_DStream objects can be re-used multiple times. 697 * 698 * Use ZSTD_initDStream() to start a new decompression operation. 699 * @return : recommended first input size 700 * Alternatively, use advanced API to set specific properties. 701 * 702 * Use ZSTD_decompressStream() repetitively to consume your input. 703 * The function will update both `pos` fields. 704 * If `input.pos < input.size`, some input has not been consumed. 705 * It's up to the caller to present again remaining data. 706 * The function tries to flush all data decoded immediately, respecting output buffer size. 707 * If `output.pos < output.size`, decoder has flushed everything it could. 708 * But if `output.pos == output.size`, there might be some data left within internal buffers., 709 * In which case, call ZSTD_decompressStream() again to flush whatever remains in the buffer. 710 * Note : with no additional input provided, amount of data flushed is necessarily <= ZSTD_BLOCKSIZE_MAX. 711 * @return : 0 when a frame is completely decoded and fully flushed, 712 * or an error code, which can be tested using ZSTD_isError(), 713 * or any other value > 0, which means there is still some decoding or flushing to do to complete current frame : 714 * the return value is a suggested next input size (just a hint for better latency) 715 * that will never request more than the remaining frame size. 716 * *******************************************************************************/ 717 718 typedef ZSTD_DCtx ZSTD_DStream; /**< DCtx and DStream are now effectively same object (>= v1.3.0) */ 719 /* For compatibility with versions <= v1.2.0, prefer differentiating them. */ 720 /*===== ZSTD_DStream management functions =====*/ 721 ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void); 722 ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds); 723 724 /*===== Streaming decompression functions =====*/ 725 726 /* This function is redundant with the advanced API and equivalent to: 727 * 728 * ZSTD_DCtx_reset(zds); 729 * ZSTD_DCtx_refDDict(zds, NULL); 730 */ 731 ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds); 732 733 ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input); 734 735 ZSTDLIB_API size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */ 736 ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */ 737 738 739 /************************** 740 * Simple dictionary API 741 ***************************/ 742 /*! ZSTD_compress_usingDict() : 743 * Compression at an explicit compression level using a Dictionary. 744 * A dictionary can be any arbitrary data segment (also called a prefix), 745 * or a buffer with specified information (see dictBuilder/zdict.h). 746 * Note : This function loads the dictionary, resulting in significant startup delay. 747 * It's intended for a dictionary used only once. 748 * Note 2 : When `dict == NULL || dictSize < 8` no dictionary is used. */ 749 ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, 750 void* dst, size_t dstCapacity, 751 const void* src, size_t srcSize, 752 const void* dict,size_t dictSize, 753 int compressionLevel); 754 755 /*! ZSTD_decompress_usingDict() : 756 * Decompression using a known Dictionary. 757 * Dictionary must be identical to the one used during compression. 758 * Note : This function loads the dictionary, resulting in significant startup delay. 759 * It's intended for a dictionary used only once. 760 * Note : When `dict == NULL || dictSize < 8` no dictionary is used. */ 761 ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx, 762 void* dst, size_t dstCapacity, 763 const void* src, size_t srcSize, 764 const void* dict,size_t dictSize); 765 766 767 /*********************************** 768 * Bulk processing dictionary API 769 **********************************/ 770 typedef struct ZSTD_CDict_s ZSTD_CDict; 771 772 /*! ZSTD_createCDict() : 773 * When compressing multiple messages / blocks using the same dictionary, it's recommended to load it only once. 774 * ZSTD_createCDict() will create a digested dictionary, ready to start future compression operations without startup cost. 775 * ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only. 776 * `dictBuffer` can be released after ZSTD_CDict creation, because its content is copied within CDict. 777 * Consider experimental function `ZSTD_createCDict_byReference()` if you prefer to not duplicate `dictBuffer` content. 778 * Note : A ZSTD_CDict can be created from an empty dictBuffer, but it is inefficient when used to compress small data. */ 779 ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize, 780 int compressionLevel); 781 782 /*! ZSTD_freeCDict() : 783 * Function frees memory allocated by ZSTD_createCDict(). */ 784 ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict); 785 786 /*! ZSTD_compress_usingCDict() : 787 * Compression using a digested Dictionary. 788 * Recommended when same dictionary is used multiple times. 789 * Note : compression level is _decided at dictionary creation time_, 790 * and frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) */ 791 ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx, 792 void* dst, size_t dstCapacity, 793 const void* src, size_t srcSize, 794 const ZSTD_CDict* cdict); 795 796 797 typedef struct ZSTD_DDict_s ZSTD_DDict; 798 799 /*! ZSTD_createDDict() : 800 * Create a digested dictionary, ready to start decompression operation without startup delay. 801 * dictBuffer can be released after DDict creation, as its content is copied inside DDict. */ 802 ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize); 803 804 /*! ZSTD_freeDDict() : 805 * Function frees memory allocated with ZSTD_createDDict() */ 806 ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict); 807 808 /*! ZSTD_decompress_usingDDict() : 809 * Decompression using a digested Dictionary. 810 * Recommended when same dictionary is used multiple times. */ 811 ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx, 812 void* dst, size_t dstCapacity, 813 const void* src, size_t srcSize, 814 const ZSTD_DDict* ddict); 815 816 817 /******************************** 818 * Dictionary helper functions 819 *******************************/ 820 821 /*! ZSTD_getDictID_fromDict() : 822 * Provides the dictID stored within dictionary. 823 * if @return == 0, the dictionary is not conformant with Zstandard specification. 824 * It can still be loaded, but as a content-only dictionary. */ 825 ZSTDLIB_API unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize); 826 827 /*! ZSTD_getDictID_fromDDict() : 828 * Provides the dictID of the dictionary loaded into `ddict`. 829 * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty. 830 * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */ 831 ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict); 832 833 /*! ZSTD_getDictID_fromFrame() : 834 * Provides the dictID required to decompressed the frame stored within `src`. 835 * If @return == 0, the dictID could not be decoded. 836 * This could for one of the following reasons : 837 * - The frame does not require a dictionary to be decoded (most common case). 838 * - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden information. 839 * Note : this use case also happens when using a non-conformant dictionary. 840 * - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`). 841 * - This is not a Zstandard frame. 842 * When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. */ 843 ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize); 844 845 846 /******************************************************************************* 847 * Advanced dictionary and prefix API 848 * 849 * This API allows dictionaries to be used with ZSTD_compress2(), 850 * ZSTD_compressStream2(), and ZSTD_decompress(). Dictionaries are sticky, and 851 * only reset with the context is reset with ZSTD_reset_parameters or 852 * ZSTD_reset_session_and_parameters. Prefixes are single-use. 853 ******************************************************************************/ 854 855 856 /*! ZSTD_CCtx_loadDictionary() : 857 * Create an internal CDict from `dict` buffer. 858 * Decompression will have to use same dictionary. 859 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 860 * Special: Loading a NULL (or 0-size) dictionary invalidates previous dictionary, 861 * meaning "return to no-dictionary mode". 862 * Note 1 : Dictionary is sticky, it will be used for all future compressed frames. 863 * To return to "no-dictionary" situation, load a NULL dictionary (or reset parameters). 864 * Note 2 : Loading a dictionary involves building tables. 865 * It's also a CPU consuming operation, with non-negligible impact on latency. 866 * Tables are dependent on compression parameters, and for this reason, 867 * compression parameters can no longer be changed after loading a dictionary. 868 * Note 3 :`dict` content will be copied internally. 869 * Use experimental ZSTD_CCtx_loadDictionary_byReference() to reference content instead. 870 * In such a case, dictionary buffer must outlive its users. 871 * Note 4 : Use ZSTD_CCtx_loadDictionary_advanced() 872 * to precisely select how dictionary content must be interpreted. */ 873 ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); 874 875 /*! ZSTD_CCtx_refCDict() : 876 * Reference a prepared dictionary, to be used for all next compressed frames. 877 * Note that compression parameters are enforced from within CDict, 878 * and supersede any compression parameter previously set within CCtx. 879 * The parameters ignored are labled as "superseded-by-cdict" in the ZSTD_cParameter enum docs. 880 * The ignored parameters will be used again if the CCtx is returned to no-dictionary mode. 881 * The dictionary will remain valid for future compressed frames using same CCtx. 882 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 883 * Special : Referencing a NULL CDict means "return to no-dictionary mode". 884 * Note 1 : Currently, only one dictionary can be managed. 885 * Referencing a new dictionary effectively "discards" any previous one. 886 * Note 2 : CDict is just referenced, its lifetime must outlive its usage within CCtx. */ 887 ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); 888 889 /*! ZSTD_CCtx_refPrefix() : 890 * Reference a prefix (single-usage dictionary) for next compressed frame. 891 * A prefix is **only used once**. Tables are discarded at end of frame (ZSTD_e_end). 892 * Decompression will need same prefix to properly regenerate data. 893 * Compressing with a prefix is similar in outcome as performing a diff and compressing it, 894 * but performs much faster, especially during decompression (compression speed is tunable with compression level). 895 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 896 * Special: Adding any prefix (including NULL) invalidates any previous prefix or dictionary 897 * Note 1 : Prefix buffer is referenced. It **must** outlive compression. 898 * Its content must remain unmodified during compression. 899 * Note 2 : If the intention is to diff some large src data blob with some prior version of itself, 900 * ensure that the window size is large enough to contain the entire source. 901 * See ZSTD_c_windowLog. 902 * Note 3 : Referencing a prefix involves building tables, which are dependent on compression parameters. 903 * It's a CPU consuming operation, with non-negligible impact on latency. 904 * If there is a need to use the same prefix multiple times, consider loadDictionary instead. 905 * Note 4 : By default, the prefix is interpreted as raw content (ZSTD_dm_rawContent). 906 * Use experimental ZSTD_CCtx_refPrefix_advanced() to alter dictionary interpretation. */ 907 ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, 908 const void* prefix, size_t prefixSize); 909 910 /*! ZSTD_DCtx_loadDictionary() : 911 * Create an internal DDict from dict buffer, 912 * to be used to decompress next frames. 913 * The dictionary remains valid for all future frames, until explicitly invalidated. 914 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 915 * Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary, 916 * meaning "return to no-dictionary mode". 917 * Note 1 : Loading a dictionary involves building tables, 918 * which has a non-negligible impact on CPU usage and latency. 919 * It's recommended to "load once, use many times", to amortize the cost 920 * Note 2 :`dict` content will be copied internally, so `dict` can be released after loading. 921 * Use ZSTD_DCtx_loadDictionary_byReference() to reference dictionary content instead. 922 * Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to take control of 923 * how dictionary content is loaded and interpreted. 924 */ 925 ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); 926 927 /*! ZSTD_DCtx_refDDict() : 928 * Reference a prepared dictionary, to be used to decompress next frames. 929 * The dictionary remains active for decompression of future frames using same DCtx. 930 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 931 * Note 1 : Currently, only one dictionary can be managed. 932 * Referencing a new dictionary effectively "discards" any previous one. 933 * Special: referencing a NULL DDict means "return to no-dictionary mode". 934 * Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx. 935 */ 936 ZSTDLIB_API size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); 937 938 /*! ZSTD_DCtx_refPrefix() : 939 * Reference a prefix (single-usage dictionary) to decompress next frame. 940 * This is the reverse operation of ZSTD_CCtx_refPrefix(), 941 * and must use the same prefix as the one used during compression. 942 * Prefix is **only used once**. Reference is discarded at end of frame. 943 * End of frame is reached when ZSTD_decompressStream() returns 0. 944 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 945 * Note 1 : Adding any prefix (including NULL) invalidates any previously set prefix or dictionary 946 * Note 2 : Prefix buffer is referenced. It **must** outlive decompression. 947 * Prefix buffer must remain unmodified up to the end of frame, 948 * reached when ZSTD_decompressStream() returns 0. 949 * Note 3 : By default, the prefix is treated as raw content (ZSTD_dm_rawContent). 950 * Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode (Experimental section) 951 * Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost. 952 * A full dictionary is more costly, as it requires building tables. 953 */ 954 ZSTDLIB_API size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, 955 const void* prefix, size_t prefixSize); 956 957 /* === Memory management === */ 958 959 /*! ZSTD_sizeof_*() : 960 * These functions give the _current_ memory usage of selected object. 961 * Note that object memory usage can evolve (increase or decrease) over time. */ 962 ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx); 963 ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx); 964 ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); 965 ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); 966 ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict); 967 ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict); 968 969 #endif /* ZSTD_H_235446 */ 970 971 972 /**************************************************************************************** 973 * ADVANCED AND EXPERIMENTAL FUNCTIONS 974 **************************************************************************************** 975 * The definitions in the following section are considered experimental. 976 * They are provided for advanced scenarios. 977 * They should never be used with a dynamic library, as prototypes may change in the future. 978 * Use them only in association with static linking. 979 * ***************************************************************************************/ 980 981 #if defined(ZSTD_STATIC_LINKING_ONLY) && !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY) 982 #define ZSTD_H_ZSTD_STATIC_LINKING_ONLY 983 984 /**************************************************************************************** 985 * experimental API (static linking only) 986 **************************************************************************************** 987 * The following symbols and constants 988 * are not planned to join "stable API" status in the near future. 989 * They can still change in future versions. 990 * Some of them are planned to remain in the static_only section indefinitely. 991 * Some of them might be removed in the future (especially when redundant with existing stable functions) 992 * ***************************************************************************************/ 993 994 #define ZSTD_FRAMEHEADERSIZE_PREFIX 5 /* minimum input size required to query frame header size */ 995 #define ZSTD_FRAMEHEADERSIZE_MIN 6 996 #define ZSTD_FRAMEHEADERSIZE_MAX 18 /* can be useful for static allocation */ 997 #define ZSTD_SKIPPABLEHEADERSIZE 8 998 999 /* compression parameter bounds */ 1000 #define ZSTD_WINDOWLOG_MAX_32 30 1001 #define ZSTD_WINDOWLOG_MAX_64 31 1002 #define ZSTD_WINDOWLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64)) 1003 #define ZSTD_WINDOWLOG_MIN 10 1004 #define ZSTD_HASHLOG_MAX ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30) 1005 #define ZSTD_HASHLOG_MIN 6 1006 #define ZSTD_CHAINLOG_MAX_32 29 1007 #define ZSTD_CHAINLOG_MAX_64 30 1008 #define ZSTD_CHAINLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64)) 1009 #define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN 1010 #define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1) 1011 #define ZSTD_SEARCHLOG_MIN 1 1012 #define ZSTD_MINMATCH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */ 1013 #define ZSTD_MINMATCH_MIN 3 /* only for ZSTD_btopt+, faster strategies are limited to 4 */ 1014 #define ZSTD_TARGETLENGTH_MAX ZSTD_BLOCKSIZE_MAX 1015 #define ZSTD_TARGETLENGTH_MIN 0 /* note : comparing this constant to an unsigned results in a tautological test */ 1016 #define ZSTD_STRATEGY_MIN ZSTD_fast 1017 #define ZSTD_STRATEGY_MAX ZSTD_btultra2 1018 1019 1020 #define ZSTD_OVERLAPLOG_MIN 0 1021 #define ZSTD_OVERLAPLOG_MAX 9 1022 1023 #define ZSTD_WINDOWLOG_LIMIT_DEFAULT 27 /* by default, the streaming decoder will refuse any frame 1024 * requiring larger than (1<<ZSTD_WINDOWLOG_LIMIT_DEFAULT) window size, 1025 * to preserve host's memory from unreasonable requirements. 1026 * This limit can be overridden using ZSTD_DCtx_setParameter(,ZSTD_d_windowLogMax,). 1027 * The limit does not apply for one-pass decoders (such as ZSTD_decompress()), since no additional memory is allocated */ 1028 1029 1030 /* LDM parameter bounds */ 1031 #define ZSTD_LDM_HASHLOG_MIN ZSTD_HASHLOG_MIN 1032 #define ZSTD_LDM_HASHLOG_MAX ZSTD_HASHLOG_MAX 1033 #define ZSTD_LDM_MINMATCH_MIN 4 1034 #define ZSTD_LDM_MINMATCH_MAX 4096 1035 #define ZSTD_LDM_BUCKETSIZELOG_MIN 1 1036 #define ZSTD_LDM_BUCKETSIZELOG_MAX 8 1037 #define ZSTD_LDM_HASHRATELOG_MIN 0 1038 #define ZSTD_LDM_HASHRATELOG_MAX (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN) 1039 1040 /* internal */ 1041 #define ZSTD_HASHLOG3_MAX 17 1042 1043 1044 /* --- Advanced types --- */ 1045 1046 typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params; 1047 1048 typedef struct { 1049 unsigned windowLog; /**< largest match distance : larger == more compression, more memory needed during decompression */ 1050 unsigned chainLog; /**< fully searched segment : larger == more compression, slower, more memory (useless for fast) */ 1051 unsigned hashLog; /**< dispatch table : larger == faster, more memory */ 1052 unsigned searchLog; /**< nb of searches : larger == more compression, slower */ 1053 unsigned minMatch; /**< match length searched : larger == faster decompression, sometimes less compression */ 1054 unsigned targetLength; /**< acceptable match size for optimal parser (only) : larger == more compression, slower */ 1055 ZSTD_strategy strategy; /**< see ZSTD_strategy definition above */ 1056 } ZSTD_compressionParameters; 1057 1058 typedef struct { 1059 int contentSizeFlag; /**< 1: content size will be in frame header (when known) */ 1060 int checksumFlag; /**< 1: generate a 32-bits checksum using XXH64 algorithm at end of frame, for error detection */ 1061 int noDictIDFlag; /**< 1: no dictID will be saved into frame header (dictID is only useful for dictionary compression) */ 1062 } ZSTD_frameParameters; 1063 1064 typedef struct { 1065 ZSTD_compressionParameters cParams; 1066 ZSTD_frameParameters fParams; 1067 } ZSTD_parameters; 1068 1069 typedef enum { 1070 ZSTD_dct_auto = 0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */ 1071 ZSTD_dct_rawContent = 1, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */ 1072 ZSTD_dct_fullDict = 2 /* refuses to load a dictionary if it does not respect Zstandard's specification, starting with ZSTD_MAGIC_DICTIONARY */ 1073 } ZSTD_dictContentType_e; 1074 1075 typedef enum { 1076 ZSTD_dlm_byCopy = 0, /**< Copy dictionary content internally */ 1077 ZSTD_dlm_byRef = 1, /**< Reference dictionary content -- the dictionary buffer must outlive its users. */ 1078 } ZSTD_dictLoadMethod_e; 1079 1080 typedef enum { 1081 /* Opened question : should we have a format ZSTD_f_auto ? 1082 * Today, it would mean exactly the same as ZSTD_f_zstd1. 1083 * But, in the future, should several formats become supported, 1084 * on the compression side, it would mean "default format". 1085 * On the decompression side, it would mean "automatic format detection", 1086 * so that ZSTD_f_zstd1 would mean "accept *only* zstd frames". 1087 * Since meaning is a little different, another option could be to define different enums for compression and decompression. 1088 * This question could be kept for later, when there are actually multiple formats to support, 1089 * but there is also the question of pinning enum values, and pinning value `0` is especially important */ 1090 ZSTD_f_zstd1 = 0, /* zstd frame format, specified in zstd_compression_format.md (default) */ 1091 ZSTD_f_zstd1_magicless = 1, /* Variant of zstd frame format, without initial 4-bytes magic number. 1092 * Useful to save 4 bytes per generated frame. 1093 * Decoder cannot recognise automatically this format, requiring this instruction. */ 1094 } ZSTD_format_e; 1095 1096 typedef enum { 1097 /* Note: this enum and the behavior it controls are effectively internal 1098 * implementation details of the compressor. They are expected to continue 1099 * to evolve and should be considered only in the context of extremely 1100 * advanced performance tuning. 1101 * 1102 * Zstd currently supports the use of a CDict in two ways: 1103 * 1104 * - The contents of the CDict can be copied into the working context. This 1105 * means that the compression can search both the dictionary and input 1106 * while operating on a single set of internal tables. This makes 1107 * the compression faster per-byte of input. However, the initial copy of 1108 * the CDict's tables incurs a fixed cost at the beginning of the 1109 * compression. For small compressions (< 8 KB), that copy can dominate 1110 * the cost of the compression. 1111 * 1112 * - The CDict's tables can be used in-place. In this model, compression is 1113 * slower per input byte, because the compressor has to search two sets of 1114 * tables. However, this model incurs no start-up cost (as long as the 1115 * working context's tables can be reused). For small inputs, this can be 1116 * faster than copying the CDict's tables. 1117 * 1118 * Zstd has a simple internal heuristic that selects which strategy to use 1119 * at the beginning of a compression. However, if experimentation shows that 1120 * Zstd is making poor choices, it is possible to override that choice with 1121 * this enum. 1122 */ 1123 ZSTD_dictDefaultAttach = 0, /* Use the default heuristic. */ 1124 ZSTD_dictForceAttach = 1, /* Never copy the dictionary. */ 1125 ZSTD_dictForceCopy = 2, /* Always copy the dictionary. */ 1126 } ZSTD_dictAttachPref_e; 1127 1128 typedef enum { 1129 ZSTD_lcm_auto = 0, /**< Automatically determine the compression mode based on the compression level. 1130 * Negative compression levels will be uncompressed, and positive compression 1131 * levels will be compressed. */ 1132 ZSTD_lcm_huffman = 1, /**< Always attempt Huffman compression. Uncompressed literals will still be 1133 * emitted if Huffman compression is not profitable. */ 1134 ZSTD_lcm_uncompressed = 2, /**< Always emit uncompressed literals. */ 1135 } ZSTD_literalCompressionMode_e; 1136 1137 1138 /*************************************** 1139 * Frame size functions 1140 ***************************************/ 1141 1142 /*! ZSTD_findDecompressedSize() : 1143 * `src` should point to the start of a series of ZSTD encoded and/or skippable frames 1144 * `srcSize` must be the _exact_ size of this series 1145 * (i.e. there should be a frame boundary at `src + srcSize`) 1146 * @return : - decompressed size of all data in all successive frames 1147 * - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN 1148 * - if an error occurred: ZSTD_CONTENTSIZE_ERROR 1149 * 1150 * note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode. 1151 * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. 1152 * In which case, it's necessary to use streaming mode to decompress data. 1153 * note 2 : decompressed size is always present when compression is done with ZSTD_compress() 1154 * note 3 : decompressed size can be very large (64-bits value), 1155 * potentially larger than what local system can handle as a single memory segment. 1156 * In which case, it's necessary to use streaming mode to decompress data. 1157 * note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified. 1158 * Always ensure result fits within application's authorized limits. 1159 * Each application can set its own limits. 1160 * note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to 1161 * read each contained frame header. This is fast as most of the data is skipped, 1162 * however it does mean that all frame data must be present and valid. */ 1163 ZSTDLIB_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize); 1164 1165 /** ZSTD_decompressBound() : 1166 * `src` should point to the start of a series of ZSTD encoded and/or skippable frames 1167 * `srcSize` must be the _exact_ size of this series 1168 * (i.e. there should be a frame boundary at `src + srcSize`) 1169 * @return : - upper-bound for the decompressed size of all data in all successive frames 1170 * - if an error occured: ZSTD_CONTENTSIZE_ERROR 1171 * 1172 * note 1 : an error can occur if `src` contains an invalid or incorrectly formatted frame. 1173 * note 2 : the upper-bound is exact when the decompressed size field is available in every ZSTD encoded frame of `src`. 1174 * in this case, `ZSTD_findDecompressedSize` and `ZSTD_decompressBound` return the same value. 1175 * note 3 : when the decompressed size field isn't available, the upper-bound for that frame is calculated by: 1176 * upper-bound = # blocks * min(128 KB, Window_Size) 1177 */ 1178 ZSTDLIB_API unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize); 1179 1180 /*! ZSTD_frameHeaderSize() : 1181 * srcSize must be >= ZSTD_FRAMEHEADERSIZE_PREFIX. 1182 * @return : size of the Frame Header, 1183 * or an error code (if srcSize is too small) */ 1184 ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize); 1185 1186 1187 /*************************************** 1188 * Memory management 1189 ***************************************/ 1190 1191 /*! ZSTD_estimate*() : 1192 * These functions make it possible to estimate memory usage 1193 * of a future {D,C}Ctx, before its creation. 1194 * ZSTD_estimateCCtxSize() will provide a budget large enough for any compression level up to selected one. 1195 * It will also consider src size to be arbitrarily "large", which is worst case. 1196 * If srcSize is known to always be small, ZSTD_estimateCCtxSize_usingCParams() can provide a tighter estimation. 1197 * ZSTD_estimateCCtxSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. 1198 * ZSTD_estimateCCtxSize_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. 1199 * Note : CCtx size estimation is only correct for single-threaded compression. */ 1200 ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel); 1201 ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams); 1202 ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params); 1203 ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void); 1204 1205 /*! ZSTD_estimateCStreamSize() : 1206 * ZSTD_estimateCStreamSize() will provide a budget large enough for any compression level up to selected one. 1207 * It will also consider src size to be arbitrarily "large", which is worst case. 1208 * If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation. 1209 * ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. 1210 * 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. 1211 * Note : CStream size estimation is only correct for single-threaded compression. 1212 * ZSTD_DStream memory budget depends on window Size. 1213 * This information can be passed manually, using ZSTD_estimateDStreamSize, 1214 * or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame(); 1215 * Note : if streaming is init with function ZSTD_init?Stream_usingDict(), 1216 * an internal ?Dict will be created, which additional size is not estimated here. 1217 * In this case, get total size by adding ZSTD_estimate?DictSize */ 1218 ZSTDLIB_API size_t ZSTD_estimateCStreamSize(int compressionLevel); 1219 ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams); 1220 ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params); 1221 ZSTDLIB_API size_t ZSTD_estimateDStreamSize(size_t windowSize); 1222 ZSTDLIB_API size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize); 1223 1224 /*! ZSTD_estimate?DictSize() : 1225 * ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict(). 1226 * ZSTD_estimateCDictSize_advanced() makes it possible to control compression parameters precisely, like ZSTD_createCDict_advanced(). 1227 * Note : dictionaries created by reference (`ZSTD_dlm_byRef`) are logically smaller. 1228 */ 1229 ZSTDLIB_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel); 1230 ZSTDLIB_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod); 1231 ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod); 1232 1233 /*! ZSTD_initStatic*() : 1234 * Initialize an object using a pre-allocated fixed-size buffer. 1235 * workspace: The memory area to emplace the object into. 1236 * Provided pointer *must be 8-bytes aligned*. 1237 * Buffer must outlive object. 1238 * workspaceSize: Use ZSTD_estimate*Size() to determine 1239 * how large workspace must be to support target scenario. 1240 * @return : pointer to object (same address as workspace, just different type), 1241 * or NULL if error (size too small, incorrect alignment, etc.) 1242 * Note : zstd will never resize nor malloc() when using a static buffer. 1243 * If the object requires more memory than available, 1244 * zstd will just error out (typically ZSTD_error_memory_allocation). 1245 * Note 2 : there is no corresponding "free" function. 1246 * Since workspace is allocated externally, it must be freed externally too. 1247 * Note 3 : cParams : use ZSTD_getCParams() to convert a compression level 1248 * into its associated cParams. 1249 * Limitation 1 : currently not compatible with internal dictionary creation, triggered by 1250 * ZSTD_CCtx_loadDictionary(), ZSTD_initCStream_usingDict() or ZSTD_initDStream_usingDict(). 1251 * Limitation 2 : static cctx currently not compatible with multi-threading. 1252 * Limitation 3 : static dctx is incompatible with legacy support. 1253 */ 1254 ZSTDLIB_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize); 1255 ZSTDLIB_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticCCtx() */ 1256 1257 ZSTDLIB_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize); 1258 ZSTDLIB_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /**< same as ZSTD_initStaticDCtx() */ 1259 1260 ZSTDLIB_API const ZSTD_CDict* ZSTD_initStaticCDict( 1261 void* workspace, size_t workspaceSize, 1262 const void* dict, size_t dictSize, 1263 ZSTD_dictLoadMethod_e dictLoadMethod, 1264 ZSTD_dictContentType_e dictContentType, 1265 ZSTD_compressionParameters cParams); 1266 1267 ZSTDLIB_API const ZSTD_DDict* ZSTD_initStaticDDict( 1268 void* workspace, size_t workspaceSize, 1269 const void* dict, size_t dictSize, 1270 ZSTD_dictLoadMethod_e dictLoadMethod, 1271 ZSTD_dictContentType_e dictContentType); 1272 1273 1274 /*! Custom memory allocation : 1275 * These prototypes make it possible to pass your own allocation/free functions. 1276 * ZSTD_customMem is provided at creation time, using ZSTD_create*_advanced() variants listed below. 1277 * All allocation/free operations will be completed using these custom variants instead of regular <stdlib.h> ones. 1278 */ 1279 typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size); 1280 typedef void (*ZSTD_freeFunction) (void* opaque, void* address); 1281 typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem; 1282 static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; /**< this constant defers to stdlib's functions */ 1283 1284 ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem); 1285 ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem); 1286 ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem); 1287 ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem); 1288 1289 ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, 1290 ZSTD_dictLoadMethod_e dictLoadMethod, 1291 ZSTD_dictContentType_e dictContentType, 1292 ZSTD_compressionParameters cParams, 1293 ZSTD_customMem customMem); 1294 1295 ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize, 1296 ZSTD_dictLoadMethod_e dictLoadMethod, 1297 ZSTD_dictContentType_e dictContentType, 1298 ZSTD_customMem customMem); 1299 1300 1301 1302 /*************************************** 1303 * Advanced compression functions 1304 ***************************************/ 1305 1306 /*! ZSTD_createCDict_byReference() : 1307 * Create a digested dictionary for compression 1308 * Dictionary content is just referenced, not duplicated. 1309 * As a consequence, `dictBuffer` **must** outlive CDict, 1310 * and its content must remain unmodified throughout the lifetime of CDict. */ 1311 ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel); 1312 1313 /*! ZSTD_getCParams() : 1314 * @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize. 1315 * `estimatedSrcSize` value is optional, select 0 if not known */ 1316 ZSTDLIB_API ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); 1317 1318 /*! ZSTD_getParams() : 1319 * same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of sub-component `ZSTD_compressionParameters`. 1320 * All fields of `ZSTD_frameParameters` are set to default : contentSize=1, checksum=0, noDictID=0 */ 1321 ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); 1322 1323 /*! ZSTD_checkCParams() : 1324 * Ensure param values remain within authorized range. 1325 * @return 0 on success, or an error code (can be checked with ZSTD_isError()) */ 1326 ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params); 1327 1328 /*! ZSTD_adjustCParams() : 1329 * optimize params for a given `srcSize` and `dictSize`. 1330 * `srcSize` can be unknown, in which case use ZSTD_CONTENTSIZE_UNKNOWN. 1331 * `dictSize` must be `0` when there is no dictionary. 1332 * cPar can be invalid : all parameters will be clamped within valid range in the @return struct. 1333 * This function never fails (wide contract) */ 1334 ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize); 1335 1336 /*! ZSTD_compress_advanced() : 1337 * Same as ZSTD_compress_usingDict(), with fine-tune control over compression parameters (by structure) */ 1338 ZSTDLIB_API size_t ZSTD_compress_advanced(ZSTD_CCtx* cctx, 1339 void* dst, size_t dstCapacity, 1340 const void* src, size_t srcSize, 1341 const void* dict,size_t dictSize, 1342 ZSTD_parameters params); 1343 1344 /*! ZSTD_compress_usingCDict_advanced() : 1345 * Same as ZSTD_compress_usingCDict(), with fine-tune control over frame parameters */ 1346 ZSTDLIB_API size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx, 1347 void* dst, size_t dstCapacity, 1348 const void* src, size_t srcSize, 1349 const ZSTD_CDict* cdict, 1350 ZSTD_frameParameters fParams); 1351 1352 1353 /*! ZSTD_CCtx_loadDictionary_byReference() : 1354 * Same as ZSTD_CCtx_loadDictionary(), but dictionary content is referenced, instead of being copied into CCtx. 1355 * It saves some memory, but also requires that `dict` outlives its usage within `cctx` */ 1356 ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); 1357 1358 /*! ZSTD_CCtx_loadDictionary_advanced() : 1359 * Same as ZSTD_CCtx_loadDictionary(), but gives finer control over 1360 * how to load the dictionary (by copy ? by reference ?) 1361 * and how to interpret it (automatic ? force raw mode ? full mode only ?) */ 1362 ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType); 1363 1364 /*! ZSTD_CCtx_refPrefix_advanced() : 1365 * Same as ZSTD_CCtx_refPrefix(), but gives finer control over 1366 * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */ 1367 ZSTDLIB_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType); 1368 1369 /* === experimental parameters === */ 1370 /* these parameters can be used with ZSTD_setParameter() 1371 * they are not guaranteed to remain supported in the future */ 1372 1373 /* Enables rsyncable mode, 1374 * which makes compressed files more rsync friendly 1375 * by adding periodic synchronization points to the compressed data. 1376 * The target average block size is ZSTD_c_jobSize / 2. 1377 * It's possible to modify the job size to increase or decrease 1378 * the granularity of the synchronization point. 1379 * Once the jobSize is smaller than the window size, 1380 * it will result in compression ratio degradation. 1381 * NOTE 1: rsyncable mode only works when multithreading is enabled. 1382 * NOTE 2: rsyncable performs poorly in combination with long range mode, 1383 * since it will decrease the effectiveness of synchronization points, 1384 * though mileage may vary. 1385 * NOTE 3: Rsyncable mode limits maximum compression speed to ~400 MB/s. 1386 * If the selected compression level is already running significantly slower, 1387 * the overall speed won't be significantly impacted. 1388 */ 1389 #define ZSTD_c_rsyncable ZSTD_c_experimentalParam1 1390 1391 /* Select a compression format. 1392 * The value must be of type ZSTD_format_e. 1393 * See ZSTD_format_e enum definition for details */ 1394 #define ZSTD_c_format ZSTD_c_experimentalParam2 1395 1396 /* Force back-reference distances to remain < windowSize, 1397 * even when referencing into Dictionary content (default:0) */ 1398 #define ZSTD_c_forceMaxWindow ZSTD_c_experimentalParam3 1399 1400 /* Controls whether the contents of a CDict 1401 * are used in place, or copied into the working context. 1402 * Accepts values from the ZSTD_dictAttachPref_e enum. 1403 * See the comments on that enum for an explanation of the feature. */ 1404 #define ZSTD_c_forceAttachDict ZSTD_c_experimentalParam4 1405 1406 /* Controls how the literals are compressed (default is auto). 1407 * The value must be of type ZSTD_literalCompressionMode_e. 1408 * See ZSTD_literalCompressionMode_t enum definition for details. 1409 */ 1410 #define ZSTD_c_literalCompressionMode ZSTD_c_experimentalParam5 1411 1412 /*! ZSTD_CCtx_getParameter() : 1413 * Get the requested compression parameter value, selected by enum ZSTD_cParameter, 1414 * and store it into int* value. 1415 * @return : 0, or an error code (which can be tested with ZSTD_isError()). 1416 */ 1417 ZSTDLIB_API size_t ZSTD_CCtx_getParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value); 1418 1419 1420 /*! ZSTD_CCtx_params : 1421 * Quick howto : 1422 * - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure 1423 * - ZSTD_CCtxParams_setParameter() : Push parameters one by one into 1424 * an existing ZSTD_CCtx_params structure. 1425 * This is similar to 1426 * ZSTD_CCtx_setParameter(). 1427 * - ZSTD_CCtx_setParametersUsingCCtxParams() : Apply parameters to 1428 * an existing CCtx. 1429 * These parameters will be applied to 1430 * all subsequent frames. 1431 * - ZSTD_compressStream2() : Do compression using the CCtx. 1432 * - ZSTD_freeCCtxParams() : Free the memory. 1433 * 1434 * This can be used with ZSTD_estimateCCtxSize_advanced_usingCCtxParams() 1435 * for static allocation of CCtx for single-threaded compression. 1436 */ 1437 ZSTDLIB_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void); 1438 ZSTDLIB_API size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params); 1439 1440 /*! ZSTD_CCtxParams_reset() : 1441 * Reset params to default values. 1442 */ 1443 ZSTDLIB_API size_t ZSTD_CCtxParams_reset(ZSTD_CCtx_params* params); 1444 1445 /*! ZSTD_CCtxParams_init() : 1446 * Initializes the compression parameters of cctxParams according to 1447 * compression level. All other parameters are reset to their default values. 1448 */ 1449 ZSTDLIB_API size_t ZSTD_CCtxParams_init(ZSTD_CCtx_params* cctxParams, int compressionLevel); 1450 1451 /*! ZSTD_CCtxParams_init_advanced() : 1452 * Initializes the compression and frame parameters of cctxParams according to 1453 * params. All other parameters are reset to their default values. 1454 */ 1455 ZSTDLIB_API size_t ZSTD_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params); 1456 1457 /*! ZSTD_CCtxParams_setParameter() : 1458 * Similar to ZSTD_CCtx_setParameter. 1459 * Set one compression parameter, selected by enum ZSTD_cParameter. 1460 * Parameters must be applied to a ZSTD_CCtx using ZSTD_CCtx_setParametersUsingCCtxParams(). 1461 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 1462 */ 1463 ZSTDLIB_API size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int value); 1464 1465 /*! ZSTD_CCtxParams_getParameter() : 1466 * Similar to ZSTD_CCtx_getParameter. 1467 * Get the requested value of one compression parameter, selected by enum ZSTD_cParameter. 1468 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 1469 */ 1470 ZSTDLIB_API size_t ZSTD_CCtxParams_getParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value); 1471 1472 /*! ZSTD_CCtx_setParametersUsingCCtxParams() : 1473 * Apply a set of ZSTD_CCtx_params to the compression context. 1474 * This can be done even after compression is started, 1475 * if nbWorkers==0, this will have no impact until a new compression is started. 1476 * if nbWorkers>=1, new parameters will be picked up at next job, 1477 * with a few restrictions (windowLog, pledgedSrcSize, nbWorkers, jobSize, and overlapLog are not updated). 1478 */ 1479 ZSTDLIB_API size_t ZSTD_CCtx_setParametersUsingCCtxParams( 1480 ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params); 1481 1482 /*! ZSTD_compressStream2_simpleArgs() : 1483 * Same as ZSTD_compressStream2(), 1484 * but using only integral types as arguments. 1485 * This variant might be helpful for binders from dynamic languages 1486 * which have troubles handling structures containing memory pointers. 1487 */ 1488 ZSTDLIB_API size_t ZSTD_compressStream2_simpleArgs ( 1489 ZSTD_CCtx* cctx, 1490 void* dst, size_t dstCapacity, size_t* dstPos, 1491 const void* src, size_t srcSize, size_t* srcPos, 1492 ZSTD_EndDirective endOp); 1493 1494 1495 /*************************************** 1496 * Advanced decompression functions 1497 ***************************************/ 1498 1499 /*! ZSTD_isFrame() : 1500 * Tells if the content of `buffer` starts with a valid Frame Identifier. 1501 * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0. 1502 * Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled. 1503 * Note 3 : Skippable Frame Identifiers are considered valid. */ 1504 ZSTDLIB_API unsigned ZSTD_isFrame(const void* buffer, size_t size); 1505 1506 /*! ZSTD_createDDict_byReference() : 1507 * Create a digested dictionary, ready to start decompression operation without startup delay. 1508 * Dictionary content is referenced, and therefore stays in dictBuffer. 1509 * It is important that dictBuffer outlives DDict, 1510 * it must remain read accessible throughout the lifetime of DDict */ 1511 ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize); 1512 1513 /*! ZSTD_DCtx_loadDictionary_byReference() : 1514 * Same as ZSTD_DCtx_loadDictionary(), 1515 * but references `dict` content instead of copying it into `dctx`. 1516 * This saves memory if `dict` remains around., 1517 * However, it's imperative that `dict` remains accessible (and unmodified) while being used, so it must outlive decompression. */ 1518 ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); 1519 1520 /*! ZSTD_DCtx_loadDictionary_advanced() : 1521 * Same as ZSTD_DCtx_loadDictionary(), 1522 * but gives direct control over 1523 * how to load the dictionary (by copy ? by reference ?) 1524 * and how to interpret it (automatic ? force raw mode ? full mode only ?). */ 1525 ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType); 1526 1527 /*! ZSTD_DCtx_refPrefix_advanced() : 1528 * Same as ZSTD_DCtx_refPrefix(), but gives finer control over 1529 * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */ 1530 ZSTDLIB_API size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType); 1531 1532 /*! ZSTD_DCtx_setMaxWindowSize() : 1533 * Refuses allocating internal buffers for frames requiring a window size larger than provided limit. 1534 * This protects a decoder context from reserving too much memory for itself (potential attack scenario). 1535 * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. 1536 * By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT) 1537 * @return : 0, or an error code (which can be tested using ZSTD_isError()). 1538 */ 1539 ZSTDLIB_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize); 1540 1541 /* ZSTD_d_format 1542 * experimental parameter, 1543 * allowing selection between ZSTD_format_e input compression formats 1544 */ 1545 #define ZSTD_d_format ZSTD_d_experimentalParam1 1546 1547 /*! ZSTD_DCtx_setFormat() : 1548 * Instruct the decoder context about what kind of data to decode next. 1549 * This instruction is mandatory to decode data without a fully-formed header, 1550 * such ZSTD_f_zstd1_magicless for example. 1551 * @return : 0, or an error code (which can be tested using ZSTD_isError()). */ 1552 ZSTDLIB_API size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format); 1553 1554 /*! ZSTD_decompressStream_simpleArgs() : 1555 * Same as ZSTD_decompressStream(), 1556 * but using only integral types as arguments. 1557 * This can be helpful for binders from dynamic languages 1558 * which have troubles handling structures containing memory pointers. 1559 */ 1560 ZSTDLIB_API size_t ZSTD_decompressStream_simpleArgs ( 1561 ZSTD_DCtx* dctx, 1562 void* dst, size_t dstCapacity, size_t* dstPos, 1563 const void* src, size_t srcSize, size_t* srcPos); 1564 1565 1566 /******************************************************************** 1567 * Advanced streaming functions 1568 * Warning : most of these functions are now redundant with the Advanced API. 1569 * Once Advanced API reaches "stable" status, 1570 * redundant functions will be deprecated, and then at some point removed. 1571 ********************************************************************/ 1572 1573 /*===== Advanced Streaming compression functions =====*/ 1574 /**! ZSTD_initCStream_srcSize() : 1575 * This function is deprecated, and equivalent to: 1576 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 1577 * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any) 1578 * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); 1579 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); 1580 * 1581 * pledgedSrcSize must be correct. If it is not known at init time, use 1582 * ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs, 1583 * "0" also disables frame content size field. It may be enabled in the future. 1584 */ 1585 ZSTDLIB_API size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize); 1586 /**! ZSTD_initCStream_usingDict() : 1587 * This function is deprecated, and is equivalent to: 1588 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 1589 * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); 1590 * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize); 1591 * 1592 * Creates of an internal CDict (incompatible with static CCtx), except if 1593 * dict == NULL or dictSize < 8, in which case no dict is used. 1594 * Note: dict is loaded with ZSTD_dm_auto (treated as a full zstd dictionary if 1595 * it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy. 1596 */ 1597 ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); 1598 /**! ZSTD_initCStream_advanced() : 1599 * This function is deprecated, and is approximately equivalent to: 1600 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 1601 * ZSTD_CCtx_setZstdParams(zcs, params); // Set the zstd params and leave the rest as-is 1602 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); 1603 * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize); 1604 * 1605 * pledgedSrcSize must be correct. If srcSize is not known at init time, use 1606 * value ZSTD_CONTENTSIZE_UNKNOWN. dict is loaded with ZSTD_dm_auto and ZSTD_dlm_byCopy. 1607 */ 1608 ZSTDLIB_API size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize, 1609 ZSTD_parameters params, unsigned long long pledgedSrcSize); 1610 /**! ZSTD_initCStream_usingCDict() : 1611 * This function is deprecated, and equivalent to: 1612 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 1613 * ZSTD_CCtx_refCDict(zcs, cdict); 1614 * 1615 * note : cdict will just be referenced, and must outlive compression session 1616 */ 1617 ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict); 1618 /**! ZSTD_initCStream_usingCDict_advanced() : 1619 * This function is deprecated, and is approximately equivalent to: 1620 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 1621 * ZSTD_CCtx_setZstdFrameParams(zcs, fParams); // Set the zstd frame params and leave the rest as-is 1622 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); 1623 * ZSTD_CCtx_refCDict(zcs, cdict); 1624 * 1625 * same as ZSTD_initCStream_usingCDict(), with control over frame parameters. 1626 * pledgedSrcSize must be correct. If srcSize is not known at init time, use 1627 * value ZSTD_CONTENTSIZE_UNKNOWN. 1628 */ 1629 ZSTDLIB_API size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, ZSTD_frameParameters fParams, unsigned long long pledgedSrcSize); 1630 1631 /*! ZSTD_resetCStream() : 1632 * This function is deprecated, and is equivalent to: 1633 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 1634 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); 1635 * 1636 * start a new frame, using same parameters from previous frame. 1637 * This is typically useful to skip dictionary loading stage, since it will re-use it in-place. 1638 * Note that zcs must be init at least once before using ZSTD_resetCStream(). 1639 * If pledgedSrcSize is not known at reset time, use macro ZSTD_CONTENTSIZE_UNKNOWN. 1640 * If pledgedSrcSize > 0, its value must be correct, as it will be written in header, and controlled at the end. 1641 * For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs, 1642 * but it will change to mean "empty" in future version, so use macro ZSTD_CONTENTSIZE_UNKNOWN instead. 1643 * @return : 0, or an error code (which can be tested using ZSTD_isError()) 1644 */ 1645 ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); 1646 1647 1648 typedef struct { 1649 unsigned long long ingested; /* nb input bytes read and buffered */ 1650 unsigned long long consumed; /* nb input bytes actually compressed */ 1651 unsigned long long produced; /* nb of compressed bytes generated and buffered */ 1652 unsigned long long flushed; /* nb of compressed bytes flushed : not provided; can be tracked from caller side */ 1653 unsigned currentJobID; /* MT only : latest started job nb */ 1654 unsigned nbActiveWorkers; /* MT only : nb of workers actively compressing at probe time */ 1655 } ZSTD_frameProgression; 1656 1657 /* ZSTD_getFrameProgression() : 1658 * tells how much data has been ingested (read from input) 1659 * consumed (input actually compressed) and produced (output) for current frame. 1660 * Note : (ingested - consumed) is amount of input data buffered internally, not yet compressed. 1661 * Aggregates progression inside active worker threads. 1662 */ 1663 ZSTDLIB_API ZSTD_frameProgression ZSTD_getFrameProgression(const ZSTD_CCtx* cctx); 1664 1665 /*! ZSTD_toFlushNow() : 1666 * Tell how many bytes are ready to be flushed immediately. 1667 * Useful for multithreading scenarios (nbWorkers >= 1). 1668 * Probe the oldest active job, defined as oldest job not yet entirely flushed, 1669 * and check its output buffer. 1670 * @return : amount of data stored in oldest job and ready to be flushed immediately. 1671 * if @return == 0, it means either : 1672 * + there is no active job (could be checked with ZSTD_frameProgression()), or 1673 * + oldest job is still actively compressing data, 1674 * but everything it has produced has also been flushed so far, 1675 * therefore flush speed is limited by production speed of oldest job 1676 * irrespective of the speed of concurrent (and newer) jobs. 1677 */ 1678 ZSTDLIB_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx); 1679 1680 1681 /*===== Advanced Streaming decompression functions =====*/ 1682 /** 1683 * This function is deprecated, and is equivalent to: 1684 * 1685 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); 1686 * ZSTD_DCtx_loadDictionary(zds, dict, dictSize); 1687 * 1688 * note: no dictionary will be used if dict == NULL or dictSize < 8 1689 */ 1690 ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); 1691 /** 1692 * This function is deprecated, and is equivalent to: 1693 * 1694 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); 1695 * ZSTD_DCtx_refDDict(zds, ddict); 1696 * 1697 * note : ddict is referenced, it must outlive decompression session 1698 */ 1699 ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); 1700 /** 1701 * This function is deprecated, and is equivalent to: 1702 * 1703 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); 1704 * 1705 * re-use decompression parameters from previous init; saves dictionary loading 1706 */ 1707 ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); 1708 1709 1710 /********************************************************************* 1711 * Buffer-less and synchronous inner streaming functions 1712 * 1713 * This is an advanced API, giving full control over buffer management, for users which need direct control over memory. 1714 * But it's also a complex one, with several restrictions, documented below. 1715 * Prefer normal streaming API for an easier experience. 1716 ********************************************************************* */ 1717 1718 /** 1719 Buffer-less streaming compression (synchronous mode) 1720 1721 A ZSTD_CCtx object is required to track streaming operations. 1722 Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource. 1723 ZSTD_CCtx object can be re-used multiple times within successive compression operations. 1724 1725 Start by initializing a context. 1726 Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary compression, 1727 or ZSTD_compressBegin_advanced(), for finer parameter control. 1728 It's also possible to duplicate a reference context which has already been initialized, using ZSTD_copyCCtx() 1729 1730 Then, consume your input using ZSTD_compressContinue(). 1731 There are some important considerations to keep in mind when using this advanced function : 1732 - ZSTD_compressContinue() has no internal buffer. It uses externally provided buffers only. 1733 - Interface is synchronous : input is consumed entirely and produces 1+ compressed blocks. 1734 - Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario. 1735 Worst case evaluation is provided by ZSTD_compressBound(). 1736 ZSTD_compressContinue() doesn't guarantee recover after a failed compression. 1737 - ZSTD_compressContinue() presumes prior input ***is still accessible and unmodified*** (up to maximum distance size, see WindowLog). 1738 It remembers all previous contiguous blocks, plus one separated memory segment (which can itself consists of multiple contiguous blocks) 1739 - ZSTD_compressContinue() detects that prior input has been overwritten when `src` buffer overlaps. 1740 In which case, it will "discard" the relevant memory section from its history. 1741 1742 Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum. 1743 It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame. 1744 Without last block mark, frames are considered unfinished (hence corrupted) by compliant decoders. 1745 1746 `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress again. 1747 */ 1748 1749 /*===== Buffer-less streaming compression functions =====*/ 1750 ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel); 1751 ZSTDLIB_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel); 1752 ZSTDLIB_API 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 */ 1753 ZSTDLIB_API size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); /**< note: fails if cdict==NULL */ 1754 ZSTDLIB_API 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 */ 1755 ZSTDLIB_API 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 */ 1756 1757 ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 1758 ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 1759 1760 1761 /*- 1762 Buffer-less streaming decompression (synchronous mode) 1763 1764 A ZSTD_DCtx object is required to track streaming operations. 1765 Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it. 1766 A ZSTD_DCtx object can be re-used multiple times. 1767 1768 First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader(). 1769 Frame header is extracted from the beginning of compressed frame, so providing only the frame's beginning is enough. 1770 Data fragment must be large enough to ensure successful decoding. 1771 `ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough. 1772 @result : 0 : successful decoding, the `ZSTD_frameHeader` structure is correctly filled. 1773 >0 : `srcSize` is too small, please provide at least @result bytes on next attempt. 1774 errorCode, which can be tested using ZSTD_isError(). 1775 1776 It fills a ZSTD_frameHeader structure with important information to correctly decode the frame, 1777 such as the dictionary ID, content size, or maximum back-reference distance (`windowSize`). 1778 Note that these values could be wrong, either because of data corruption, or because a 3rd party deliberately spoofs false information. 1779 As a consequence, check that values remain within valid application range. 1780 For example, do not allocate memory blindly, check that `windowSize` is within expectation. 1781 Each application can set its own limits, depending on local restrictions. 1782 For extended interoperability, it is recommended to support `windowSize` of at least 8 MB. 1783 1784 ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize` bytes. 1785 ZSTD_decompressContinue() is very sensitive to contiguity, 1786 if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place, 1787 or that previous contiguous segment is large enough to properly handle maximum back-reference distance. 1788 There are multiple ways to guarantee this condition. 1789 1790 The most memory efficient way is to use a round buffer of sufficient size. 1791 Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(), 1792 which can @return an error code if required value is too large for current system (in 32-bits mode). 1793 In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one, 1794 up to the moment there is not enough room left in the buffer to guarantee decoding another full block, 1795 which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`. 1796 At which point, decoding can resume from the beginning of the buffer. 1797 Note that already decoded data stored in the buffer should be flushed before being overwritten. 1798 1799 There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory. 1800 1801 Finally, if you control the compression process, you can also ignore all buffer size rules, 1802 as long as the encoder and decoder progress in "lock-step", 1803 aka use exactly the same buffer sizes, break contiguity at the same place, etc. 1804 1805 Once buffers are setup, start decompression, with ZSTD_decompressBegin(). 1806 If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict(). 1807 1808 Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively. 1809 ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue(). 1810 ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail. 1811 1812 @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity). 1813 It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item. 1814 It can also be an error code, which can be tested with ZSTD_isError(). 1815 1816 A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero. 1817 Context can then be reset to start a new decompression. 1818 1819 Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType(). 1820 This information is not required to properly decode a frame. 1821 1822 == Special case : skippable frames == 1823 1824 Skippable frames allow integration of user-defined data into a flow of concatenated frames. 1825 Skippable frames will be ignored (skipped) by decompressor. 1826 The format of skippable frames is as follows : 1827 a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F 1828 b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits 1829 c) Frame Content - any content (User Data) of length equal to Frame Size 1830 For skippable frames ZSTD_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame. 1831 For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content. 1832 */ 1833 1834 /*===== Buffer-less streaming decompression functions =====*/ 1835 typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e; 1836 typedef struct { 1837 unsigned long long frameContentSize; /* if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty" */ 1838 unsigned long long windowSize; /* can be very large, up to <= frameContentSize */ 1839 unsigned blockSizeMax; 1840 ZSTD_frameType_e frameType; /* if == ZSTD_skippableFrame, frameContentSize is the size of skippable content */ 1841 unsigned headerSize; 1842 unsigned dictID; 1843 unsigned checksumFlag; 1844 } ZSTD_frameHeader; 1845 1846 /** ZSTD_getFrameHeader() : 1847 * decode Frame Header, or requires larger `srcSize`. 1848 * @return : 0, `zfhPtr` is correctly filled, 1849 * >0, `srcSize` is too small, value is wanted `srcSize` amount, 1850 * or an error code, which can be tested using ZSTD_isError() */ 1851 ZSTDLIB_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /**< doesn't consume input */ 1852 /*! ZSTD_getFrameHeader_advanced() : 1853 * same as ZSTD_getFrameHeader(), 1854 * with added capability to select a format (like ZSTD_f_zstd1_magicless) */ 1855 ZSTDLIB_API size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format); 1856 ZSTDLIB_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 */ 1857 1858 ZSTDLIB_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx); 1859 ZSTDLIB_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); 1860 ZSTDLIB_API size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); 1861 1862 ZSTDLIB_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx); 1863 ZSTDLIB_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 1864 1865 /* misc */ 1866 ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx); 1867 typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e; 1868 ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx); 1869 1870 1871 1872 1873 /* ============================ */ 1874 /** Block level API */ 1875 /* ============================ */ 1876 1877 /*! 1878 Block functions produce and decode raw zstd blocks, without frame metadata. 1879 Frame metadata cost is typically ~18 bytes, which can be non-negligible for very small blocks (< 100 bytes). 1880 User will have to take in charge required information to regenerate data, such as compressed and content sizes. 1881 1882 A few rules to respect : 1883 - Compressing and decompressing require a context structure 1884 + Use ZSTD_createCCtx() and ZSTD_createDCtx() 1885 - It is necessary to init context before starting 1886 + compression : any ZSTD_compressBegin*() variant, including with dictionary 1887 + decompression : any ZSTD_decompressBegin*() variant, including with dictionary 1888 + copyCCtx() and copyDCtx() can be used too 1889 - Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB 1890 + If input is larger than a block size, it's necessary to split input data into multiple blocks 1891 + For inputs larger than a single block, really consider using regular ZSTD_compress() instead. 1892 Frame metadata is not that costly, and quickly becomes negligible as source size grows larger. 1893 - When a block is considered not compressible enough, ZSTD_compressBlock() result will be zero. 1894 In which case, nothing is produced into `dst` ! 1895 + User must test for such outcome and deal directly with uncompressed data 1896 + ZSTD_decompressBlock() doesn't accept uncompressed data as input !!! 1897 + In case of multiple successive blocks, should some of them be uncompressed, 1898 decoder must be informed of their existence in order to follow proper history. 1899 Use ZSTD_insertBlock() for such a case. 1900 */ 1901 1902 /*===== Raw zstd block functions =====*/ 1903 ZSTDLIB_API size_t ZSTD_getBlockSize (const ZSTD_CCtx* cctx); 1904 ZSTDLIB_API size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 1905 ZSTDLIB_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 1906 ZSTDLIB_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. */ 1907 1908 1909 #endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */ 1910 1911 #if defined (__cplusplus) 1912 } 1913 #endif 1914