1 /* 2 * Copyright (c) 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 11 #ifndef ZSTD_H_235446 12 #define ZSTD_H_235446 13 14 /* ====== Dependency ======*/ 15 #include <linux/limits.h> /* INT_MAX */ 16 #include <linux/types.h> /* size_t */ 17 18 19 /* ===== ZSTDLIB_API : control library symbols visibility ===== */ 20 #define ZSTDLIB_VISIBILITY 21 #define ZSTDLIB_API ZSTDLIB_VISIBILITY 22 23 24 /* ***************************************************************************** 25 Introduction 26 27 zstd, short for Zstandard, is a fast lossless compression algorithm, targeting 28 real-time compression scenarios at zlib-level and better compression ratios. 29 The zstd compression library provides in-memory compression and decompression 30 functions. 31 32 The library supports regular compression levels from 1 up to ZSTD_maxCLevel(), 33 which is currently 22. Levels >= 20, labeled `--ultra`, should be used with 34 caution, as they require more memory. The library also offers negative 35 compression levels, which extend the range of speed vs. ratio preferences. 36 The lower the level, the faster the speed (at the cost of compression). 37 38 Compression can be done in: 39 - a single step (described as Simple API) 40 - a single step, reusing a context (described as Explicit context) 41 - unbounded multiple steps (described as Streaming compression) 42 43 The compression ratio achievable on small data can be highly improved using 44 a dictionary. Dictionary compression can be performed in: 45 - a single step (described as Simple dictionary API) 46 - a single step, reusing a dictionary (described as Bulk-processing 47 dictionary API) 48 49 Advanced experimental functions can be accessed using 50 `#define ZSTD_STATIC_LINKING_ONLY` before including zstd.h. 51 52 Advanced experimental APIs should never be used with a dynamically-linked 53 library. They are not "stable"; their definitions or signatures may change in 54 the future. Only static linking is allowed. 55 *******************************************************************************/ 56 57 /*------ Version ------*/ 58 #define ZSTD_VERSION_MAJOR 1 59 #define ZSTD_VERSION_MINOR 4 60 #define ZSTD_VERSION_RELEASE 10 61 #define ZSTD_VERSION_NUMBER (ZSTD_VERSION_MAJOR *100*100 + ZSTD_VERSION_MINOR *100 + ZSTD_VERSION_RELEASE) 62 63 /*! ZSTD_versionNumber() : 64 * Return runtime library version, the value is (MAJOR*100*100 + MINOR*100 + RELEASE). */ 65 ZSTDLIB_API unsigned ZSTD_versionNumber(void); 66 67 #define ZSTD_LIB_VERSION ZSTD_VERSION_MAJOR.ZSTD_VERSION_MINOR.ZSTD_VERSION_RELEASE 68 #define ZSTD_QUOTE(str) #str 69 #define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str) 70 #define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION) 71 72 /*! ZSTD_versionString() : 73 * Return runtime library version, like "1.4.5". Requires v1.3.0+. */ 74 ZSTDLIB_API const char* ZSTD_versionString(void); 75 76 /* ************************************* 77 * Default constant 78 ***************************************/ 79 #ifndef ZSTD_CLEVEL_DEFAULT 80 # define ZSTD_CLEVEL_DEFAULT 3 81 #endif 82 83 /* ************************************* 84 * Constants 85 ***************************************/ 86 87 /* All magic numbers are supposed read/written to/from files/memory using little-endian convention */ 88 #define ZSTD_MAGICNUMBER 0xFD2FB528 /* valid since v0.8.0 */ 89 #define ZSTD_MAGIC_DICTIONARY 0xEC30A437 /* valid since v0.7.0 */ 90 #define ZSTD_MAGIC_SKIPPABLE_START 0x184D2A50 /* all 16 values, from 0x184D2A50 to 0x184D2A5F, signal the beginning of a skippable frame */ 91 #define ZSTD_MAGIC_SKIPPABLE_MASK 0xFFFFFFF0 92 93 #define ZSTD_BLOCKSIZELOG_MAX 17 94 #define ZSTD_BLOCKSIZE_MAX (1<<ZSTD_BLOCKSIZELOG_MAX) 95 96 97 98 /* ************************************* 99 * Simple API 100 ***************************************/ 101 /*! ZSTD_compress() : 102 * Compresses `src` content as a single zstd compressed frame into already allocated `dst`. 103 * Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`. 104 * @return : compressed size written into `dst` (<= `dstCapacity), 105 * or an error code if it fails (which can be tested using ZSTD_isError()). */ 106 ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity, 107 const void* src, size_t srcSize, 108 int compressionLevel); 109 110 /*! ZSTD_decompress() : 111 * `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames. 112 * `dstCapacity` is an upper bound of originalSize to regenerate. 113 * If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data. 114 * @return : the number of bytes decompressed into `dst` (<= `dstCapacity`), 115 * or an errorCode if it fails (which can be tested using ZSTD_isError()). */ 116 ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity, 117 const void* src, size_t compressedSize); 118 119 /*! ZSTD_getFrameContentSize() : requires v1.3.0+ 120 * `src` should point to the start of a ZSTD encoded frame. 121 * `srcSize` must be at least as large as the frame header. 122 * hint : any size >= `ZSTD_frameHeaderSize_max` is large enough. 123 * @return : - decompressed size of `src` frame content, if known 124 * - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined 125 * - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) 126 * note 1 : a 0 return value means the frame is valid but "empty". 127 * note 2 : decompressed size is an optional field, it may not be present, typically in streaming mode. 128 * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. 129 * In which case, it's necessary to use streaming mode to decompress data. 130 * Optionally, application can rely on some implicit limit, 131 * as ZSTD_decompress() only needs an upper bound of decompressed size. 132 * (For example, data could be necessarily cut into blocks <= 16 KB). 133 * note 3 : decompressed size is always present when compression is completed using single-pass functions, 134 * such as ZSTD_compress(), ZSTD_compressCCtx() ZSTD_compress_usingDict() or ZSTD_compress_usingCDict(). 135 * note 4 : decompressed size can be very large (64-bits value), 136 * potentially larger than what local system can handle as a single memory segment. 137 * In which case, it's necessary to use streaming mode to decompress data. 138 * note 5 : If source is untrusted, decompressed size could be wrong or intentionally modified. 139 * Always ensure return value fits within application's authorized limits. 140 * Each application can set its own limits. 141 * note 6 : This function replaces ZSTD_getDecompressedSize() */ 142 #define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1) 143 #define ZSTD_CONTENTSIZE_ERROR (0ULL - 2) 144 ZSTDLIB_API unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize); 145 146 /*! ZSTD_getDecompressedSize() : 147 * NOTE: This function is now obsolete, in favor of ZSTD_getFrameContentSize(). 148 * Both functions work the same way, but ZSTD_getDecompressedSize() blends 149 * "empty", "unknown" and "error" results to the same return value (0), 150 * while ZSTD_getFrameContentSize() gives them separate return values. 151 * @return : decompressed size of `src` frame content _if known and not empty_, 0 otherwise. */ 152 ZSTDLIB_API unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize); 153 154 /*! ZSTD_findFrameCompressedSize() : 155 * `src` should point to the start of a ZSTD frame or skippable frame. 156 * `srcSize` must be >= first frame size 157 * @return : the compressed size of the first frame starting at `src`, 158 * suitable to pass as `srcSize` to `ZSTD_decompress` or similar, 159 * or an error code if input is invalid */ 160 ZSTDLIB_API size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize); 161 162 163 /*====== Helper functions ======*/ 164 #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 */ 165 ZSTDLIB_API size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case single-pass scenario */ 166 ZSTDLIB_API unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */ 167 ZSTDLIB_API const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */ 168 ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed */ 169 ZSTDLIB_API int ZSTD_maxCLevel(void); /*!< maximum compression level available */ 170 171 172 /* ************************************* 173 * Explicit context 174 ***************************************/ 175 /*= Compression context 176 * When compressing many times, 177 * it is recommended to allocate a context just once, 178 * and re-use it for each successive compression operation. 179 * This will make workload friendlier for system's memory. 180 * Note : re-using context is just a speed / resource optimization. 181 * It doesn't change the compression ratio, which remains identical. 182 * Note 2 : In multi-threaded environments, 183 * use one different context per thread for parallel execution. 184 */ 185 typedef struct ZSTD_CCtx_s ZSTD_CCtx; 186 ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void); 187 ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); /* accept NULL pointer */ 188 189 /*! ZSTD_compressCCtx() : 190 * Same as ZSTD_compress(), using an explicit ZSTD_CCtx. 191 * Important : in order to behave similarly to `ZSTD_compress()`, 192 * this function compresses at requested compression level, 193 * __ignoring any other parameter__ . 194 * If any advanced parameter was set using the advanced API, 195 * they will all be reset. Only `compressionLevel` remains. 196 */ 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); /* accept NULL pointer */ 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. 260 * See ZSTD_CCtx_refCDict() for more info (superseded-by-cdict). */ 261 ZSTD_c_compressionLevel=100, /* Set compression parameters according to pre-defined cLevel table. 262 * Note that exact compression parameters are dynamically determined, 263 * depending on both compression level and srcSize (when known). 264 * Default level is ZSTD_CLEVEL_DEFAULT==3. 265 * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT. 266 * Note 1 : it's possible to pass a negative compression level. 267 * Note 2 : setting a level does not automatically set all other compression parameters 268 * to default. Setting this will however eventually dynamically impact the compression 269 * parameters which have not been manually set. The manually set 270 * ones will 'stick'. */ 271 /* Advanced compression parameters : 272 * It's possible to pin down compression parameters to some specific values. 273 * In which case, these values are no longer dynamically selected by the compressor */ 274 ZSTD_c_windowLog=101, /* Maximum allowed back-reference distance, expressed as power of 2. 275 * This will set a memory budget for streaming decompression, 276 * with larger values requiring more memory 277 * and typically compressing more. 278 * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX. 279 * Special: value 0 means "use default windowLog". 280 * Note: Using a windowLog greater than ZSTD_WINDOWLOG_LIMIT_DEFAULT 281 * requires explicitly allowing such size at streaming decompression stage. */ 282 ZSTD_c_hashLog=102, /* Size of the initial probe table, as a power of 2. 283 * Resulting memory usage is (1 << (hashLog+2)). 284 * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX. 285 * Larger tables improve compression ratio of strategies <= dFast, 286 * and improve speed of strategies > dFast. 287 * Special: value 0 means "use default hashLog". */ 288 ZSTD_c_chainLog=103, /* Size of the multi-probe search table, as a power of 2. 289 * Resulting memory usage is (1 << (chainLog+2)). 290 * Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX. 291 * Larger tables result in better and slower compression. 292 * This parameter is useless for "fast" strategy. 293 * It's still useful when using "dfast" strategy, 294 * in which case it defines a secondary probe table. 295 * Special: value 0 means "use default chainLog". */ 296 ZSTD_c_searchLog=104, /* Number of search attempts, as a power of 2. 297 * More attempts result in better and slower compression. 298 * This parameter is useless for "fast" and "dFast" strategies. 299 * Special: value 0 means "use default searchLog". */ 300 ZSTD_c_minMatch=105, /* Minimum size of searched matches. 301 * Note that Zstandard can still find matches of smaller size, 302 * it just tweaks its search algorithm to look for this size and larger. 303 * Larger values increase compression and decompression speed, but decrease ratio. 304 * Must be clamped between ZSTD_MINMATCH_MIN and ZSTD_MINMATCH_MAX. 305 * Note that currently, for all strategies < btopt, effective minimum is 4. 306 * , for all strategies > fast, effective maximum is 6. 307 * Special: value 0 means "use default minMatchLength". */ 308 ZSTD_c_targetLength=106, /* Impact of this field depends on strategy. 309 * For strategies btopt, btultra & btultra2: 310 * Length of Match considered "good enough" to stop search. 311 * Larger values make compression stronger, and slower. 312 * For strategy fast: 313 * Distance between match sampling. 314 * Larger values make compression faster, and weaker. 315 * Special: value 0 means "use default targetLength". */ 316 ZSTD_c_strategy=107, /* See ZSTD_strategy enum definition. 317 * The higher the value of selected strategy, the more complex it is, 318 * resulting in stronger and slower compression. 319 * Special: value 0 means "use default strategy". */ 320 321 /* LDM mode parameters */ 322 ZSTD_c_enableLongDistanceMatching=160, /* Enable long distance matching. 323 * This parameter is designed to improve compression ratio 324 * for large inputs, by finding large matches at long distance. 325 * It increases memory usage and window size. 326 * Note: enabling this parameter increases default ZSTD_c_windowLog to 128 MB 327 * except when expressly set to a different value. 328 * Note: will be enabled by default if ZSTD_c_windowLog >= 128 MB and 329 * compression strategy >= ZSTD_btopt (== compression level 16+) */ 330 ZSTD_c_ldmHashLog=161, /* Size of the table for long distance matching, as a power of 2. 331 * Larger values increase memory usage and compression ratio, 332 * but decrease compression speed. 333 * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX 334 * default: windowlog - 7. 335 * Special: value 0 means "automatically determine hashlog". */ 336 ZSTD_c_ldmMinMatch=162, /* Minimum match size for long distance matcher. 337 * Larger/too small values usually decrease compression ratio. 338 * Must be clamped between ZSTD_LDM_MINMATCH_MIN and ZSTD_LDM_MINMATCH_MAX. 339 * Special: value 0 means "use default value" (default: 64). */ 340 ZSTD_c_ldmBucketSizeLog=163, /* Log size of each bucket in the LDM hash table for collision resolution. 341 * Larger values improve collision resolution but decrease compression speed. 342 * The maximum value is ZSTD_LDM_BUCKETSIZELOG_MAX. 343 * Special: value 0 means "use default value" (default: 3). */ 344 ZSTD_c_ldmHashRateLog=164, /* Frequency of inserting/looking up entries into the LDM hash table. 345 * Must be clamped between 0 and (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN). 346 * Default is MAX(0, (windowLog - ldmHashLog)), optimizing hash table usage. 347 * Larger values improve compression speed. 348 * Deviating far from default value will likely result in a compression ratio decrease. 349 * Special: value 0 means "automatically determine hashRateLog". */ 350 351 /* frame parameters */ 352 ZSTD_c_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1) 353 * Content size must be known at the beginning of compression. 354 * This is automatically the case when using ZSTD_compress2(), 355 * For streaming scenarios, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */ 356 ZSTD_c_checksumFlag=201, /* A 32-bits checksum of content is written at end of frame (default:0) */ 357 ZSTD_c_dictIDFlag=202, /* When applicable, dictionary's ID is written into frame header (default:1) */ 358 359 /* multi-threading parameters */ 360 /* These parameters are only active if multi-threading is enabled (compiled with build macro ZSTD_MULTITHREAD). 361 * Otherwise, trying to set any other value than default (0) will be a no-op and return an error. 362 * In a situation where it's unknown if the linked library supports multi-threading or not, 363 * setting ZSTD_c_nbWorkers to any value >= 1 and consulting the return value provides a quick way to check this property. 364 */ 365 ZSTD_c_nbWorkers=400, /* Select how many threads will be spawned to compress in parallel. 366 * When nbWorkers >= 1, triggers asynchronous mode when invoking ZSTD_compressStream*() : 367 * ZSTD_compressStream*() consumes input and flush output if possible, but immediately gives back control to caller, 368 * while compression is performed in parallel, within worker thread(s). 369 * (note : a strong exception to this rule is when first invocation of ZSTD_compressStream2() sets ZSTD_e_end : 370 * in which case, ZSTD_compressStream2() delegates to ZSTD_compress2(), which is always a blocking call). 371 * More workers improve speed, but also increase memory usage. 372 * Default value is `0`, aka "single-threaded mode" : no worker is spawned, 373 * compression is performed inside Caller's thread, and all invocations are blocking */ 374 ZSTD_c_jobSize=401, /* Size of a compression job. This value is enforced only when nbWorkers >= 1. 375 * Each compression job is completed in parallel, so this value can indirectly impact the nb of active threads. 376 * 0 means default, which is dynamically determined based on compression parameters. 377 * Job size must be a minimum of overlap size, or 1 MB, whichever is largest. 378 * The minimum size is automatically and transparently enforced. */ 379 ZSTD_c_overlapLog=402, /* Control the overlap size, as a fraction of window size. 380 * The overlap size is an amount of data reloaded from previous job at the beginning of a new job. 381 * It helps preserve compression ratio, while each job is compressed in parallel. 382 * This value is enforced only when nbWorkers >= 1. 383 * Larger values increase compression ratio, but decrease speed. 384 * Possible values range from 0 to 9 : 385 * - 0 means "default" : value will be determined by the library, depending on strategy 386 * - 1 means "no overlap" 387 * - 9 means "full overlap", using a full window size. 388 * Each intermediate rank increases/decreases load size by a factor 2 : 389 * 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 390 * default value varies between 6 and 9, depending on strategy */ 391 392 /* note : additional experimental parameters are also available 393 * within the experimental section of the API. 394 * At the time of this writing, they include : 395 * ZSTD_c_rsyncable 396 * ZSTD_c_format 397 * ZSTD_c_forceMaxWindow 398 * ZSTD_c_forceAttachDict 399 * ZSTD_c_literalCompressionMode 400 * ZSTD_c_targetCBlockSize 401 * ZSTD_c_srcSizeHint 402 * ZSTD_c_enableDedicatedDictSearch 403 * ZSTD_c_stableInBuffer 404 * ZSTD_c_stableOutBuffer 405 * ZSTD_c_blockDelimiters 406 * ZSTD_c_validateSequences 407 * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. 408 * note : never ever use experimentalParam? names directly; 409 * also, the enums values themselves are unstable and can still change. 410 */ 411 ZSTD_c_experimentalParam1=500, 412 ZSTD_c_experimentalParam2=10, 413 ZSTD_c_experimentalParam3=1000, 414 ZSTD_c_experimentalParam4=1001, 415 ZSTD_c_experimentalParam5=1002, 416 ZSTD_c_experimentalParam6=1003, 417 ZSTD_c_experimentalParam7=1004, 418 ZSTD_c_experimentalParam8=1005, 419 ZSTD_c_experimentalParam9=1006, 420 ZSTD_c_experimentalParam10=1007, 421 ZSTD_c_experimentalParam11=1008, 422 ZSTD_c_experimentalParam12=1009 423 } ZSTD_cParameter; 424 425 typedef struct { 426 size_t error; 427 int lowerBound; 428 int upperBound; 429 } ZSTD_bounds; 430 431 /*! ZSTD_cParam_getBounds() : 432 * All parameters must belong to an interval with lower and upper bounds, 433 * otherwise they will either trigger an error or be automatically clamped. 434 * @return : a structure, ZSTD_bounds, which contains 435 * - an error status field, which must be tested using ZSTD_isError() 436 * - lower and upper bounds, both inclusive 437 */ 438 ZSTDLIB_API ZSTD_bounds ZSTD_cParam_getBounds(ZSTD_cParameter cParam); 439 440 /*! ZSTD_CCtx_setParameter() : 441 * Set one compression parameter, selected by enum ZSTD_cParameter. 442 * All parameters have valid bounds. Bounds can be queried using ZSTD_cParam_getBounds(). 443 * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). 444 * Setting a parameter is generally only possible during frame initialization (before starting compression). 445 * Exception : when using multi-threading mode (nbWorkers >= 1), 446 * the following parameters can be updated _during_ compression (within same frame): 447 * => compressionLevel, hashLog, chainLog, searchLog, minMatch, targetLength and strategy. 448 * new parameters will be active for next job only (after a flush()). 449 * @return : an error code (which can be tested using ZSTD_isError()). 450 */ 451 ZSTDLIB_API size_t ZSTD_CCtx_setParameter(ZSTD_CCtx* cctx, ZSTD_cParameter param, int value); 452 453 /*! ZSTD_CCtx_setPledgedSrcSize() : 454 * Total input data size to be compressed as a single frame. 455 * Value will be written in frame header, unless if explicitly forbidden using ZSTD_c_contentSizeFlag. 456 * This value will also be controlled at end of frame, and trigger an error if not respected. 457 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 458 * Note 1 : pledgedSrcSize==0 actually means zero, aka an empty frame. 459 * In order to mean "unknown content size", pass constant ZSTD_CONTENTSIZE_UNKNOWN. 460 * ZSTD_CONTENTSIZE_UNKNOWN is default value for any new frame. 461 * Note 2 : pledgedSrcSize is only valid once, for the next frame. 462 * It's discarded at the end of the frame, and replaced by ZSTD_CONTENTSIZE_UNKNOWN. 463 * Note 3 : Whenever all input data is provided and consumed in a single round, 464 * for example with ZSTD_compress2(), 465 * or invoking immediately ZSTD_compressStream2(,,,ZSTD_e_end), 466 * this value is automatically overridden by srcSize instead. 467 */ 468 ZSTDLIB_API size_t ZSTD_CCtx_setPledgedSrcSize(ZSTD_CCtx* cctx, unsigned long long pledgedSrcSize); 469 470 typedef enum { 471 ZSTD_reset_session_only = 1, 472 ZSTD_reset_parameters = 2, 473 ZSTD_reset_session_and_parameters = 3 474 } ZSTD_ResetDirective; 475 476 /*! ZSTD_CCtx_reset() : 477 * There are 2 different things that can be reset, independently or jointly : 478 * - The session : will stop compressing current frame, and make CCtx ready to start a new one. 479 * Useful after an error, or to interrupt any ongoing compression. 480 * Any internal data not yet flushed is cancelled. 481 * Compression parameters and dictionary remain unchanged. 482 * They will be used to compress next frame. 483 * Resetting session never fails. 484 * - The parameters : changes all parameters back to "default". 485 * This removes any reference to any dictionary too. 486 * Parameters can only be changed between 2 sessions (i.e. no compression is currently ongoing) 487 * otherwise the reset fails, and function returns an error value (which can be tested using ZSTD_isError()) 488 * - Both : similar to resetting the session, followed by resetting parameters. 489 */ 490 ZSTDLIB_API size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset); 491 492 /*! ZSTD_compress2() : 493 * Behave the same as ZSTD_compressCCtx(), but compression parameters are set using the advanced API. 494 * ZSTD_compress2() always starts a new frame. 495 * Should cctx hold data from a previously unfinished frame, everything about it is forgotten. 496 * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() 497 * - The function is always blocking, returns when compression is completed. 498 * Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`. 499 * @return : compressed size written into `dst` (<= `dstCapacity), 500 * or an error code if it fails (which can be tested using ZSTD_isError()). 501 */ 502 ZSTDLIB_API size_t ZSTD_compress2( ZSTD_CCtx* cctx, 503 void* dst, size_t dstCapacity, 504 const void* src, size_t srcSize); 505 506 507 /* ************************************* 508 * Advanced decompression API 509 ***************************************/ 510 511 /* The advanced API pushes parameters one by one into an existing DCtx context. 512 * Parameters are sticky, and remain valid for all following frames 513 * using the same DCtx context. 514 * It's possible to reset parameters to default values using ZSTD_DCtx_reset(). 515 * Note : This API is compatible with existing ZSTD_decompressDCtx() and ZSTD_decompressStream(). 516 * Therefore, no new decompression function is necessary. 517 */ 518 519 typedef enum { 520 521 ZSTD_d_windowLogMax=100, /* Select a size limit (in power of 2) beyond which 522 * the streaming API will refuse to allocate memory buffer 523 * in order to protect the host from unreasonable memory requirements. 524 * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. 525 * By default, a decompression context accepts window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT). 526 * Special: value 0 means "use default maximum windowLog". */ 527 528 /* note : additional experimental parameters are also available 529 * within the experimental section of the API. 530 * At the time of this writing, they include : 531 * ZSTD_d_format 532 * ZSTD_d_stableOutBuffer 533 * ZSTD_d_forceIgnoreChecksum 534 * ZSTD_d_refMultipleDDicts 535 * Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them. 536 * note : never ever use experimentalParam? names directly 537 */ 538 ZSTD_d_experimentalParam1=1000, 539 ZSTD_d_experimentalParam2=1001, 540 ZSTD_d_experimentalParam3=1002, 541 ZSTD_d_experimentalParam4=1003 542 543 } ZSTD_dParameter; 544 545 /*! ZSTD_dParam_getBounds() : 546 * All parameters must belong to an interval with lower and upper bounds, 547 * otherwise they will either trigger an error or be automatically clamped. 548 * @return : a structure, ZSTD_bounds, which contains 549 * - an error status field, which must be tested using ZSTD_isError() 550 * - both lower and upper bounds, inclusive 551 */ 552 ZSTDLIB_API ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam); 553 554 /*! ZSTD_DCtx_setParameter() : 555 * Set one compression parameter, selected by enum ZSTD_dParameter. 556 * All parameters have valid bounds. Bounds can be queried using ZSTD_dParam_getBounds(). 557 * Providing a value beyond bound will either clamp it, or trigger an error (depending on parameter). 558 * Setting a parameter is only possible during frame initialization (before starting decompression). 559 * @return : 0, or an error code (which can be tested using ZSTD_isError()). 560 */ 561 ZSTDLIB_API size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int value); 562 563 /*! ZSTD_DCtx_reset() : 564 * Return a DCtx to clean state. 565 * Session and parameters can be reset jointly or separately. 566 * Parameters can only be reset when no active frame is being decompressed. 567 * @return : 0, or an error code, which can be tested with ZSTD_isError() 568 */ 569 ZSTDLIB_API size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset); 570 571 572 /* ************************** 573 * Streaming 574 ****************************/ 575 576 typedef struct ZSTD_inBuffer_s { 577 const void* src; /*< start of input buffer */ 578 size_t size; /*< size of input buffer */ 579 size_t pos; /*< position where reading stopped. Will be updated. Necessarily 0 <= pos <= size */ 580 } ZSTD_inBuffer; 581 582 typedef struct ZSTD_outBuffer_s { 583 void* dst; /*< start of output buffer */ 584 size_t size; /*< size of output buffer */ 585 size_t pos; /*< position where writing stopped. Will be updated. Necessarily 0 <= pos <= size */ 586 } ZSTD_outBuffer; 587 588 589 590 /*-*********************************************************************** 591 * Streaming compression - HowTo 592 * 593 * A ZSTD_CStream object is required to track streaming operation. 594 * Use ZSTD_createCStream() and ZSTD_freeCStream() to create/release resources. 595 * ZSTD_CStream objects can be reused multiple times on consecutive compression operations. 596 * It is recommended to re-use ZSTD_CStream since it will play nicer with system's memory, by re-using already allocated memory. 597 * 598 * For parallel execution, use one separate ZSTD_CStream per thread. 599 * 600 * note : since v1.3.0, ZSTD_CStream and ZSTD_CCtx are the same thing. 601 * 602 * Parameters are sticky : when starting a new compression on the same context, 603 * it will re-use the same sticky parameters as previous compression session. 604 * When in doubt, it's recommended to fully initialize the context before usage. 605 * Use ZSTD_CCtx_reset() to reset the context and ZSTD_CCtx_setParameter(), 606 * ZSTD_CCtx_setPledgedSrcSize(), or ZSTD_CCtx_loadDictionary() and friends to 607 * set more specific parameters, the pledged source size, or load a dictionary. 608 * 609 * Use ZSTD_compressStream2() with ZSTD_e_continue as many times as necessary to 610 * consume input stream. The function will automatically update both `pos` 611 * fields within `input` and `output`. 612 * Note that the function may not consume the entire input, for example, because 613 * the output buffer is already full, in which case `input.pos < input.size`. 614 * The caller must check if input has been entirely consumed. 615 * If not, the caller must make some room to receive more compressed data, 616 * and then present again remaining input data. 617 * note: ZSTD_e_continue is guaranteed to make some forward progress when called, 618 * but doesn't guarantee maximal forward progress. This is especially relevant 619 * when compressing with multiple threads. The call won't block if it can 620 * consume some input, but if it can't it will wait for some, but not all, 621 * output to be flushed. 622 * @return : provides a minimum amount of data remaining to be flushed from internal buffers 623 * or an error code, which can be tested using ZSTD_isError(). 624 * 625 * At any moment, it's possible to flush whatever data might remain stuck within internal buffer, 626 * using ZSTD_compressStream2() with ZSTD_e_flush. `output->pos` will be updated. 627 * Note that, if `output->size` is too small, a single invocation with ZSTD_e_flush might not be enough (return code > 0). 628 * In which case, make some room to receive more compressed data, and call again ZSTD_compressStream2() with ZSTD_e_flush. 629 * You must continue calling ZSTD_compressStream2() with ZSTD_e_flush until it returns 0, at which point you can change the 630 * operation. 631 * note: ZSTD_e_flush will flush as much output as possible, meaning when compressing with multiple threads, it will 632 * block until the flush is complete or the output buffer is full. 633 * @return : 0 if internal buffers are entirely flushed, 634 * >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), 635 * or an error code, which can be tested using ZSTD_isError(). 636 * 637 * Calling ZSTD_compressStream2() with ZSTD_e_end instructs to finish a frame. 638 * It will perform a flush and write frame epilogue. 639 * The epilogue is required for decoders to consider a frame completed. 640 * flush operation is the same, and follows same rules as calling ZSTD_compressStream2() with ZSTD_e_flush. 641 * You must continue calling ZSTD_compressStream2() with ZSTD_e_end until it returns 0, at which point you are free to 642 * start a new frame. 643 * note: ZSTD_e_end will flush as much output as possible, meaning when compressing with multiple threads, it will 644 * block until the flush is complete or the output buffer is full. 645 * @return : 0 if frame fully completed and fully flushed, 646 * >0 if some data still present within internal buffer (the value is minimal estimation of remaining size), 647 * or an error code, which can be tested using ZSTD_isError(). 648 * 649 * *******************************************************************/ 650 651 typedef ZSTD_CCtx ZSTD_CStream; /*< CCtx and CStream are now effectively same object (>= v1.3.0) */ 652 /* Continue to distinguish them for compatibility with older versions <= v1.2.0 */ 653 /*===== ZSTD_CStream management functions =====*/ 654 ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream(void); 655 ZSTDLIB_API size_t ZSTD_freeCStream(ZSTD_CStream* zcs); /* accept NULL pointer */ 656 657 /*===== Streaming compression functions =====*/ 658 typedef enum { 659 ZSTD_e_continue=0, /* collect more data, encoder decides when to output compressed result, for optimal compression ratio */ 660 ZSTD_e_flush=1, /* flush any data provided so far, 661 * it creates (at least) one new block, that can be decoded immediately on reception; 662 * frame will continue: any future data can still reference previously compressed data, improving compression. 663 * note : multithreaded compression will block to flush as much output as possible. */ 664 ZSTD_e_end=2 /* flush any remaining data _and_ close current frame. 665 * note that frame is only closed after compressed data is fully flushed (return value == 0). 666 * After that point, any additional data starts a new frame. 667 * note : each frame is independent (does not reference any content from previous frame). 668 : note : multithreaded compression will block to flush as much output as possible. */ 669 } ZSTD_EndDirective; 670 671 /*! ZSTD_compressStream2() : 672 * Behaves about the same as ZSTD_compressStream, with additional control on end directive. 673 * - Compression parameters are pushed into CCtx before starting compression, using ZSTD_CCtx_set*() 674 * - Compression parameters cannot be changed once compression is started (save a list of exceptions in multi-threading mode) 675 * - output->pos must be <= dstCapacity, input->pos must be <= srcSize 676 * - output->pos and input->pos will be updated. They are guaranteed to remain below their respective limit. 677 * - endOp must be a valid directive 678 * - When nbWorkers==0 (default), function is blocking : it completes its job before returning to caller. 679 * - When nbWorkers>=1, function is non-blocking : it copies a portion of input, distributes jobs to internal worker threads, flush to output whatever is available, 680 * and then immediately returns, just indicating that there is some data remaining to be flushed. 681 * The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte. 682 * - 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. 683 * - @return provides a minimum amount of data remaining to be flushed from internal buffers 684 * or an error code, which can be tested using ZSTD_isError(). 685 * if @return != 0, flush is not fully completed, there is still some data left within internal buffers. 686 * This is useful for ZSTD_e_flush, since in this case more flushes are necessary to empty all buffers. 687 * For ZSTD_e_end, @return == 0 when internal buffers are fully flushed and frame is completed. 688 * - after a ZSTD_e_end directive, if internal buffer is not fully flushed (@return != 0), 689 * only ZSTD_e_end or ZSTD_e_flush operations are allowed. 690 * Before starting a new compression job, or changing compression parameters, 691 * it is required to fully flush internal buffers. 692 */ 693 ZSTDLIB_API size_t ZSTD_compressStream2( ZSTD_CCtx* cctx, 694 ZSTD_outBuffer* output, 695 ZSTD_inBuffer* input, 696 ZSTD_EndDirective endOp); 697 698 699 /* These buffer sizes are softly recommended. 700 * They are not required : ZSTD_compressStream*() happily accepts any buffer size, for both input and output. 701 * Respecting the recommended size just makes it a bit easier for ZSTD_compressStream*(), 702 * reducing the amount of memory shuffling and buffering, resulting in minor performance savings. 703 * 704 * However, note that these recommendations are from the perspective of a C caller program. 705 * If the streaming interface is invoked from some other language, 706 * especially managed ones such as Java or Go, through a foreign function interface such as jni or cgo, 707 * a major performance rule is to reduce crossing such interface to an absolute minimum. 708 * It's not rare that performance ends being spent more into the interface, rather than compression itself. 709 * In which cases, prefer using large buffers, as large as practical, 710 * for both input and output, to reduce the nb of roundtrips. 711 */ 712 ZSTDLIB_API size_t ZSTD_CStreamInSize(void); /*< recommended size for input buffer */ 713 ZSTDLIB_API size_t ZSTD_CStreamOutSize(void); /*< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block. */ 714 715 716 /* ***************************************************************************** 717 * This following is a legacy streaming API. 718 * It can be replaced by ZSTD_CCtx_reset() and ZSTD_compressStream2(). 719 * It is redundant, but remains fully supported. 720 * Advanced parameters and dictionary compression can only be used through the 721 * new API. 722 ******************************************************************************/ 723 724 /*! 725 * Equivalent to: 726 * 727 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 728 * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any) 729 * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); 730 */ 731 ZSTDLIB_API size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel); 732 /*! 733 * Alternative for ZSTD_compressStream2(zcs, output, input, ZSTD_e_continue). 734 * NOTE: The return value is different. ZSTD_compressStream() returns a hint for 735 * the next read size (if non-zero and not an error). ZSTD_compressStream2() 736 * returns the minimum nb of bytes left to flush (if non-zero and not an error). 737 */ 738 ZSTDLIB_API size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input); 739 /*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_flush). */ 740 ZSTDLIB_API size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); 741 /*! Equivalent to ZSTD_compressStream2(zcs, output, &emptyInput, ZSTD_e_end). */ 742 ZSTDLIB_API size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); 743 744 745 /*-*************************************************************************** 746 * Streaming decompression - HowTo 747 * 748 * A ZSTD_DStream object is required to track streaming operations. 749 * Use ZSTD_createDStream() and ZSTD_freeDStream() to create/release resources. 750 * ZSTD_DStream objects can be re-used multiple times. 751 * 752 * Use ZSTD_initDStream() to start a new decompression operation. 753 * @return : recommended first input size 754 * Alternatively, use advanced API to set specific properties. 755 * 756 * Use ZSTD_decompressStream() repetitively to consume your input. 757 * The function will update both `pos` fields. 758 * If `input.pos < input.size`, some input has not been consumed. 759 * It's up to the caller to present again remaining data. 760 * The function tries to flush all data decoded immediately, respecting output buffer size. 761 * If `output.pos < output.size`, decoder has flushed everything it could. 762 * But if `output.pos == output.size`, there might be some data left within internal buffers., 763 * In which case, call ZSTD_decompressStream() again to flush whatever remains in the buffer. 764 * Note : with no additional input provided, amount of data flushed is necessarily <= ZSTD_BLOCKSIZE_MAX. 765 * @return : 0 when a frame is completely decoded and fully flushed, 766 * or an error code, which can be tested using ZSTD_isError(), 767 * or any other value > 0, which means there is still some decoding or flushing to do to complete current frame : 768 * the return value is a suggested next input size (just a hint for better latency) 769 * that will never request more than the remaining frame size. 770 * *******************************************************************************/ 771 772 typedef ZSTD_DCtx ZSTD_DStream; /*< DCtx and DStream are now effectively same object (>= v1.3.0) */ 773 /* For compatibility with versions <= v1.2.0, prefer differentiating them. */ 774 /*===== ZSTD_DStream management functions =====*/ 775 ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream(void); 776 ZSTDLIB_API size_t ZSTD_freeDStream(ZSTD_DStream* zds); /* accept NULL pointer */ 777 778 /*===== Streaming decompression functions =====*/ 779 780 /* This function is redundant with the advanced API and equivalent to: 781 * 782 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); 783 * ZSTD_DCtx_refDDict(zds, NULL); 784 */ 785 ZSTDLIB_API size_t ZSTD_initDStream(ZSTD_DStream* zds); 786 787 ZSTDLIB_API size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input); 788 789 ZSTDLIB_API size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */ 790 ZSTDLIB_API size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */ 791 792 793 /* ************************ 794 * Simple dictionary API 795 ***************************/ 796 /*! ZSTD_compress_usingDict() : 797 * Compression at an explicit compression level using a Dictionary. 798 * A dictionary can be any arbitrary data segment (also called a prefix), 799 * or a buffer with specified information (see dictBuilder/zdict.h). 800 * Note : This function loads the dictionary, resulting in significant startup delay. 801 * It's intended for a dictionary used only once. 802 * Note 2 : When `dict == NULL || dictSize < 8` no dictionary is used. */ 803 ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, 804 void* dst, size_t dstCapacity, 805 const void* src, size_t srcSize, 806 const void* dict,size_t dictSize, 807 int compressionLevel); 808 809 /*! ZSTD_decompress_usingDict() : 810 * Decompression using a known Dictionary. 811 * Dictionary must be identical to the one used during compression. 812 * Note : This function loads the dictionary, resulting in significant startup delay. 813 * It's intended for a dictionary used only once. 814 * Note : When `dict == NULL || dictSize < 8` no dictionary is used. */ 815 ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx, 816 void* dst, size_t dstCapacity, 817 const void* src, size_t srcSize, 818 const void* dict,size_t dictSize); 819 820 821 /* ********************************* 822 * Bulk processing dictionary API 823 **********************************/ 824 typedef struct ZSTD_CDict_s ZSTD_CDict; 825 826 /*! ZSTD_createCDict() : 827 * When compressing multiple messages or blocks using the same dictionary, 828 * it's recommended to digest the dictionary only once, since it's a costly operation. 829 * ZSTD_createCDict() will create a state from digesting a dictionary. 830 * The resulting state can be used for future compression operations with very limited startup cost. 831 * ZSTD_CDict can be created once and shared by multiple threads concurrently, since its usage is read-only. 832 * @dictBuffer can be released after ZSTD_CDict creation, because its content is copied within CDict. 833 * Note 1 : Consider experimental function `ZSTD_createCDict_byReference()` if you prefer to not duplicate @dictBuffer content. 834 * Note 2 : A ZSTD_CDict can be created from an empty @dictBuffer, 835 * in which case the only thing that it transports is the @compressionLevel. 836 * This can be useful in a pipeline featuring ZSTD_compress_usingCDict() exclusively, 837 * expecting a ZSTD_CDict parameter with any data, including those without a known dictionary. */ 838 ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize, 839 int compressionLevel); 840 841 /*! ZSTD_freeCDict() : 842 * Function frees memory allocated by ZSTD_createCDict(). 843 * If a NULL pointer is passed, no operation is performed. */ 844 ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict); 845 846 /*! ZSTD_compress_usingCDict() : 847 * Compression using a digested Dictionary. 848 * Recommended when same dictionary is used multiple times. 849 * Note : compression level is _decided at dictionary creation time_, 850 * and frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no) */ 851 ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx, 852 void* dst, size_t dstCapacity, 853 const void* src, size_t srcSize, 854 const ZSTD_CDict* cdict); 855 856 857 typedef struct ZSTD_DDict_s ZSTD_DDict; 858 859 /*! ZSTD_createDDict() : 860 * Create a digested dictionary, ready to start decompression operation without startup delay. 861 * dictBuffer can be released after DDict creation, as its content is copied inside DDict. */ 862 ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize); 863 864 /*! ZSTD_freeDDict() : 865 * Function frees memory allocated with ZSTD_createDDict() 866 * If a NULL pointer is passed, no operation is performed. */ 867 ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict); 868 869 /*! ZSTD_decompress_usingDDict() : 870 * Decompression using a digested Dictionary. 871 * Recommended when same dictionary is used multiple times. */ 872 ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx, 873 void* dst, size_t dstCapacity, 874 const void* src, size_t srcSize, 875 const ZSTD_DDict* ddict); 876 877 878 /* ****************************** 879 * Dictionary helper functions 880 *******************************/ 881 882 /*! ZSTD_getDictID_fromDict() : 883 * Provides the dictID stored within dictionary. 884 * if @return == 0, the dictionary is not conformant with Zstandard specification. 885 * It can still be loaded, but as a content-only dictionary. */ 886 ZSTDLIB_API unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize); 887 888 /*! ZSTD_getDictID_fromDDict() : 889 * Provides the dictID of the dictionary loaded into `ddict`. 890 * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty. 891 * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */ 892 ZSTDLIB_API unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict); 893 894 /*! ZSTD_getDictID_fromFrame() : 895 * Provides the dictID required to decompressed the frame stored within `src`. 896 * If @return == 0, the dictID could not be decoded. 897 * This could for one of the following reasons : 898 * - The frame does not require a dictionary to be decoded (most common case). 899 * - The frame was built with dictID intentionally removed. Whatever dictionary is necessary is a hidden information. 900 * Note : this use case also happens when using a non-conformant dictionary. 901 * - `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`). 902 * - This is not a Zstandard frame. 903 * When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code. */ 904 ZSTDLIB_API unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize); 905 906 907 /* ***************************************************************************** 908 * Advanced dictionary and prefix API 909 * 910 * This API allows dictionaries to be used with ZSTD_compress2(), 911 * ZSTD_compressStream2(), and ZSTD_decompress(). Dictionaries are sticky, and 912 * only reset with the context is reset with ZSTD_reset_parameters or 913 * ZSTD_reset_session_and_parameters. Prefixes are single-use. 914 ******************************************************************************/ 915 916 917 /*! ZSTD_CCtx_loadDictionary() : 918 * Create an internal CDict from `dict` buffer. 919 * Decompression will have to use same dictionary. 920 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 921 * Special: Loading a NULL (or 0-size) dictionary invalidates previous dictionary, 922 * meaning "return to no-dictionary mode". 923 * Note 1 : Dictionary is sticky, it will be used for all future compressed frames. 924 * To return to "no-dictionary" situation, load a NULL dictionary (or reset parameters). 925 * Note 2 : Loading a dictionary involves building tables. 926 * It's also a CPU consuming operation, with non-negligible impact on latency. 927 * Tables are dependent on compression parameters, and for this reason, 928 * compression parameters can no longer be changed after loading a dictionary. 929 * Note 3 :`dict` content will be copied internally. 930 * Use experimental ZSTD_CCtx_loadDictionary_byReference() to reference content instead. 931 * In such a case, dictionary buffer must outlive its users. 932 * Note 4 : Use ZSTD_CCtx_loadDictionary_advanced() 933 * to precisely select how dictionary content must be interpreted. */ 934 ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); 935 936 /*! ZSTD_CCtx_refCDict() : 937 * Reference a prepared dictionary, to be used for all next compressed frames. 938 * Note that compression parameters are enforced from within CDict, 939 * and supersede any compression parameter previously set within CCtx. 940 * The parameters ignored are labelled as "superseded-by-cdict" in the ZSTD_cParameter enum docs. 941 * The ignored parameters will be used again if the CCtx is returned to no-dictionary mode. 942 * The dictionary will remain valid for future compressed frames using same CCtx. 943 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 944 * Special : Referencing a NULL CDict means "return to no-dictionary mode". 945 * Note 1 : Currently, only one dictionary can be managed. 946 * Referencing a new dictionary effectively "discards" any previous one. 947 * Note 2 : CDict is just referenced, its lifetime must outlive its usage within CCtx. */ 948 ZSTDLIB_API size_t ZSTD_CCtx_refCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); 949 950 /*! ZSTD_CCtx_refPrefix() : 951 * Reference a prefix (single-usage dictionary) for next compressed frame. 952 * A prefix is **only used once**. Tables are discarded at end of frame (ZSTD_e_end). 953 * Decompression will need same prefix to properly regenerate data. 954 * Compressing with a prefix is similar in outcome as performing a diff and compressing it, 955 * but performs much faster, especially during decompression (compression speed is tunable with compression level). 956 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 957 * Special: Adding any prefix (including NULL) invalidates any previous prefix or dictionary 958 * Note 1 : Prefix buffer is referenced. It **must** outlive compression. 959 * Its content must remain unmodified during compression. 960 * Note 2 : If the intention is to diff some large src data blob with some prior version of itself, 961 * ensure that the window size is large enough to contain the entire source. 962 * See ZSTD_c_windowLog. 963 * Note 3 : Referencing a prefix involves building tables, which are dependent on compression parameters. 964 * It's a CPU consuming operation, with non-negligible impact on latency. 965 * If there is a need to use the same prefix multiple times, consider loadDictionary instead. 966 * Note 4 : By default, the prefix is interpreted as raw content (ZSTD_dct_rawContent). 967 * Use experimental ZSTD_CCtx_refPrefix_advanced() to alter dictionary interpretation. */ 968 ZSTDLIB_API size_t ZSTD_CCtx_refPrefix(ZSTD_CCtx* cctx, 969 const void* prefix, size_t prefixSize); 970 971 /*! ZSTD_DCtx_loadDictionary() : 972 * Create an internal DDict from dict buffer, 973 * to be used to decompress next frames. 974 * The dictionary remains valid for all future frames, until explicitly invalidated. 975 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 976 * Special : Adding a NULL (or 0-size) dictionary invalidates any previous dictionary, 977 * meaning "return to no-dictionary mode". 978 * Note 1 : Loading a dictionary involves building tables, 979 * which has a non-negligible impact on CPU usage and latency. 980 * It's recommended to "load once, use many times", to amortize the cost 981 * Note 2 :`dict` content will be copied internally, so `dict` can be released after loading. 982 * Use ZSTD_DCtx_loadDictionary_byReference() to reference dictionary content instead. 983 * Note 3 : Use ZSTD_DCtx_loadDictionary_advanced() to take control of 984 * how dictionary content is loaded and interpreted. 985 */ 986 ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); 987 988 /*! ZSTD_DCtx_refDDict() : 989 * Reference a prepared dictionary, to be used to decompress next frames. 990 * The dictionary remains active for decompression of future frames using same DCtx. 991 * 992 * If called with ZSTD_d_refMultipleDDicts enabled, repeated calls of this function 993 * will store the DDict references in a table, and the DDict used for decompression 994 * will be determined at decompression time, as per the dict ID in the frame. 995 * The memory for the table is allocated on the first call to refDDict, and can be 996 * freed with ZSTD_freeDCtx(). 997 * 998 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 999 * Note 1 : Currently, only one dictionary can be managed. 1000 * Referencing a new dictionary effectively "discards" any previous one. 1001 * Special: referencing a NULL DDict means "return to no-dictionary mode". 1002 * Note 2 : DDict is just referenced, its lifetime must outlive its usage from DCtx. 1003 */ 1004 ZSTDLIB_API size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); 1005 1006 /*! ZSTD_DCtx_refPrefix() : 1007 * Reference a prefix (single-usage dictionary) to decompress next frame. 1008 * This is the reverse operation of ZSTD_CCtx_refPrefix(), 1009 * and must use the same prefix as the one used during compression. 1010 * Prefix is **only used once**. Reference is discarded at end of frame. 1011 * End of frame is reached when ZSTD_decompressStream() returns 0. 1012 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 1013 * Note 1 : Adding any prefix (including NULL) invalidates any previously set prefix or dictionary 1014 * Note 2 : Prefix buffer is referenced. It **must** outlive decompression. 1015 * Prefix buffer must remain unmodified up to the end of frame, 1016 * reached when ZSTD_decompressStream() returns 0. 1017 * Note 3 : By default, the prefix is treated as raw content (ZSTD_dct_rawContent). 1018 * Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode (Experimental section) 1019 * Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost. 1020 * A full dictionary is more costly, as it requires building tables. 1021 */ 1022 ZSTDLIB_API size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, 1023 const void* prefix, size_t prefixSize); 1024 1025 /* === Memory management === */ 1026 1027 /*! ZSTD_sizeof_*() : 1028 * These functions give the _current_ memory usage of selected object. 1029 * Note that object memory usage can evolve (increase or decrease) over time. */ 1030 ZSTDLIB_API size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx); 1031 ZSTDLIB_API size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx); 1032 ZSTDLIB_API size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); 1033 ZSTDLIB_API size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); 1034 ZSTDLIB_API size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict); 1035 ZSTDLIB_API size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict); 1036 1037 #endif /* ZSTD_H_235446 */ 1038 1039 1040 /* ************************************************************************************** 1041 * ADVANCED AND EXPERIMENTAL FUNCTIONS 1042 **************************************************************************************** 1043 * The definitions in the following section are considered experimental. 1044 * They are provided for advanced scenarios. 1045 * They should never be used with a dynamic library, as prototypes may change in the future. 1046 * Use them only in association with static linking. 1047 * ***************************************************************************************/ 1048 1049 #if !defined(ZSTD_H_ZSTD_STATIC_LINKING_ONLY) 1050 #define ZSTD_H_ZSTD_STATIC_LINKING_ONLY 1051 1052 /* ************************************************************************************** 1053 * experimental API (static linking only) 1054 **************************************************************************************** 1055 * The following symbols and constants 1056 * are not planned to join "stable API" status in the near future. 1057 * They can still change in future versions. 1058 * Some of them are planned to remain in the static_only section indefinitely. 1059 * Some of them might be removed in the future (especially when redundant with existing stable functions) 1060 * ***************************************************************************************/ 1061 1062 #define ZSTD_FRAMEHEADERSIZE_PREFIX(format) ((format) == ZSTD_f_zstd1 ? 5 : 1) /* minimum input size required to query frame header size */ 1063 #define ZSTD_FRAMEHEADERSIZE_MIN(format) ((format) == ZSTD_f_zstd1 ? 6 : 2) 1064 #define ZSTD_FRAMEHEADERSIZE_MAX 18 /* can be useful for static allocation */ 1065 #define ZSTD_SKIPPABLEHEADERSIZE 8 1066 1067 /* compression parameter bounds */ 1068 #define ZSTD_WINDOWLOG_MAX_32 30 1069 #define ZSTD_WINDOWLOG_MAX_64 31 1070 #define ZSTD_WINDOWLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_WINDOWLOG_MAX_32 : ZSTD_WINDOWLOG_MAX_64)) 1071 #define ZSTD_WINDOWLOG_MIN 10 1072 #define ZSTD_HASHLOG_MAX ((ZSTD_WINDOWLOG_MAX < 30) ? ZSTD_WINDOWLOG_MAX : 30) 1073 #define ZSTD_HASHLOG_MIN 6 1074 #define ZSTD_CHAINLOG_MAX_32 29 1075 #define ZSTD_CHAINLOG_MAX_64 30 1076 #define ZSTD_CHAINLOG_MAX ((int)(sizeof(size_t) == 4 ? ZSTD_CHAINLOG_MAX_32 : ZSTD_CHAINLOG_MAX_64)) 1077 #define ZSTD_CHAINLOG_MIN ZSTD_HASHLOG_MIN 1078 #define ZSTD_SEARCHLOG_MAX (ZSTD_WINDOWLOG_MAX-1) 1079 #define ZSTD_SEARCHLOG_MIN 1 1080 #define ZSTD_MINMATCH_MAX 7 /* only for ZSTD_fast, other strategies are limited to 6 */ 1081 #define ZSTD_MINMATCH_MIN 3 /* only for ZSTD_btopt+, faster strategies are limited to 4 */ 1082 #define ZSTD_TARGETLENGTH_MAX ZSTD_BLOCKSIZE_MAX 1083 #define ZSTD_TARGETLENGTH_MIN 0 /* note : comparing this constant to an unsigned results in a tautological test */ 1084 #define ZSTD_STRATEGY_MIN ZSTD_fast 1085 #define ZSTD_STRATEGY_MAX ZSTD_btultra2 1086 1087 1088 #define ZSTD_OVERLAPLOG_MIN 0 1089 #define ZSTD_OVERLAPLOG_MAX 9 1090 1091 #define ZSTD_WINDOWLOG_LIMIT_DEFAULT 27 /* by default, the streaming decoder will refuse any frame 1092 * requiring larger than (1<<ZSTD_WINDOWLOG_LIMIT_DEFAULT) window size, 1093 * to preserve host's memory from unreasonable requirements. 1094 * This limit can be overridden using ZSTD_DCtx_setParameter(,ZSTD_d_windowLogMax,). 1095 * The limit does not apply for one-pass decoders (such as ZSTD_decompress()), since no additional memory is allocated */ 1096 1097 1098 /* LDM parameter bounds */ 1099 #define ZSTD_LDM_HASHLOG_MIN ZSTD_HASHLOG_MIN 1100 #define ZSTD_LDM_HASHLOG_MAX ZSTD_HASHLOG_MAX 1101 #define ZSTD_LDM_MINMATCH_MIN 4 1102 #define ZSTD_LDM_MINMATCH_MAX 4096 1103 #define ZSTD_LDM_BUCKETSIZELOG_MIN 1 1104 #define ZSTD_LDM_BUCKETSIZELOG_MAX 8 1105 #define ZSTD_LDM_HASHRATELOG_MIN 0 1106 #define ZSTD_LDM_HASHRATELOG_MAX (ZSTD_WINDOWLOG_MAX - ZSTD_HASHLOG_MIN) 1107 1108 /* Advanced parameter bounds */ 1109 #define ZSTD_TARGETCBLOCKSIZE_MIN 64 1110 #define ZSTD_TARGETCBLOCKSIZE_MAX ZSTD_BLOCKSIZE_MAX 1111 #define ZSTD_SRCSIZEHINT_MIN 0 1112 #define ZSTD_SRCSIZEHINT_MAX INT_MAX 1113 1114 /* internal */ 1115 #define ZSTD_HASHLOG3_MAX 17 1116 1117 1118 /* --- Advanced types --- */ 1119 1120 typedef struct ZSTD_CCtx_params_s ZSTD_CCtx_params; 1121 1122 typedef struct { 1123 unsigned int offset; /* The offset of the match. (NOT the same as the offset code) 1124 * If offset == 0 and matchLength == 0, this sequence represents the last 1125 * literals in the block of litLength size. 1126 */ 1127 1128 unsigned int litLength; /* Literal length of the sequence. */ 1129 unsigned int matchLength; /* Match length of the sequence. */ 1130 1131 /* Note: Users of this API may provide a sequence with matchLength == litLength == offset == 0. 1132 * In this case, we will treat the sequence as a marker for a block boundary. 1133 */ 1134 1135 unsigned int rep; /* Represents which repeat offset is represented by the field 'offset'. 1136 * Ranges from [0, 3]. 1137 * 1138 * Repeat offsets are essentially previous offsets from previous sequences sorted in 1139 * recency order. For more detail, see doc/zstd_compression_format.md 1140 * 1141 * If rep == 0, then 'offset' does not contain a repeat offset. 1142 * If rep > 0: 1143 * If litLength != 0: 1144 * rep == 1 --> offset == repeat_offset_1 1145 * rep == 2 --> offset == repeat_offset_2 1146 * rep == 3 --> offset == repeat_offset_3 1147 * If litLength == 0: 1148 * rep == 1 --> offset == repeat_offset_2 1149 * rep == 2 --> offset == repeat_offset_3 1150 * rep == 3 --> offset == repeat_offset_1 - 1 1151 * 1152 * Note: This field is optional. ZSTD_generateSequences() will calculate the value of 1153 * 'rep', but repeat offsets do not necessarily need to be calculated from an external 1154 * sequence provider's perspective. For example, ZSTD_compressSequences() does not 1155 * use this 'rep' field at all (as of now). 1156 */ 1157 } ZSTD_Sequence; 1158 1159 typedef struct { 1160 unsigned windowLog; /*< largest match distance : larger == more compression, more memory needed during decompression */ 1161 unsigned chainLog; /*< fully searched segment : larger == more compression, slower, more memory (useless for fast) */ 1162 unsigned hashLog; /*< dispatch table : larger == faster, more memory */ 1163 unsigned searchLog; /*< nb of searches : larger == more compression, slower */ 1164 unsigned minMatch; /*< match length searched : larger == faster decompression, sometimes less compression */ 1165 unsigned targetLength; /*< acceptable match size for optimal parser (only) : larger == more compression, slower */ 1166 ZSTD_strategy strategy; /*< see ZSTD_strategy definition above */ 1167 } ZSTD_compressionParameters; 1168 1169 typedef struct { 1170 int contentSizeFlag; /*< 1: content size will be in frame header (when known) */ 1171 int checksumFlag; /*< 1: generate a 32-bits checksum using XXH64 algorithm at end of frame, for error detection */ 1172 int noDictIDFlag; /*< 1: no dictID will be saved into frame header (dictID is only useful for dictionary compression) */ 1173 } ZSTD_frameParameters; 1174 1175 typedef struct { 1176 ZSTD_compressionParameters cParams; 1177 ZSTD_frameParameters fParams; 1178 } ZSTD_parameters; 1179 1180 typedef enum { 1181 ZSTD_dct_auto = 0, /* dictionary is "full" when starting with ZSTD_MAGIC_DICTIONARY, otherwise it is "rawContent" */ 1182 ZSTD_dct_rawContent = 1, /* ensures dictionary is always loaded as rawContent, even if it starts with ZSTD_MAGIC_DICTIONARY */ 1183 ZSTD_dct_fullDict = 2 /* refuses to load a dictionary if it does not respect Zstandard's specification, starting with ZSTD_MAGIC_DICTIONARY */ 1184 } ZSTD_dictContentType_e; 1185 1186 typedef enum { 1187 ZSTD_dlm_byCopy = 0, /*< Copy dictionary content internally */ 1188 ZSTD_dlm_byRef = 1 /*< Reference dictionary content -- the dictionary buffer must outlive its users. */ 1189 } ZSTD_dictLoadMethod_e; 1190 1191 typedef enum { 1192 ZSTD_f_zstd1 = 0, /* zstd frame format, specified in zstd_compression_format.md (default) */ 1193 ZSTD_f_zstd1_magicless = 1 /* Variant of zstd frame format, without initial 4-bytes magic number. 1194 * Useful to save 4 bytes per generated frame. 1195 * Decoder cannot recognise automatically this format, requiring this instruction. */ 1196 } ZSTD_format_e; 1197 1198 typedef enum { 1199 /* Note: this enum controls ZSTD_d_forceIgnoreChecksum */ 1200 ZSTD_d_validateChecksum = 0, 1201 ZSTD_d_ignoreChecksum = 1 1202 } ZSTD_forceIgnoreChecksum_e; 1203 1204 typedef enum { 1205 /* Note: this enum controls ZSTD_d_refMultipleDDicts */ 1206 ZSTD_rmd_refSingleDDict = 0, 1207 ZSTD_rmd_refMultipleDDicts = 1 1208 } ZSTD_refMultipleDDicts_e; 1209 1210 typedef enum { 1211 /* Note: this enum and the behavior it controls are effectively internal 1212 * implementation details of the compressor. They are expected to continue 1213 * to evolve and should be considered only in the context of extremely 1214 * advanced performance tuning. 1215 * 1216 * Zstd currently supports the use of a CDict in three ways: 1217 * 1218 * - The contents of the CDict can be copied into the working context. This 1219 * means that the compression can search both the dictionary and input 1220 * while operating on a single set of internal tables. This makes 1221 * the compression faster per-byte of input. However, the initial copy of 1222 * the CDict's tables incurs a fixed cost at the beginning of the 1223 * compression. For small compressions (< 8 KB), that copy can dominate 1224 * the cost of the compression. 1225 * 1226 * - The CDict's tables can be used in-place. In this model, compression is 1227 * slower per input byte, because the compressor has to search two sets of 1228 * tables. However, this model incurs no start-up cost (as long as the 1229 * working context's tables can be reused). For small inputs, this can be 1230 * faster than copying the CDict's tables. 1231 * 1232 * - The CDict's tables are not used at all, and instead we use the working 1233 * context alone to reload the dictionary and use params based on the source 1234 * size. See ZSTD_compress_insertDictionary() and ZSTD_compress_usingDict(). 1235 * This method is effective when the dictionary sizes are very small relative 1236 * to the input size, and the input size is fairly large to begin with. 1237 * 1238 * Zstd has a simple internal heuristic that selects which strategy to use 1239 * at the beginning of a compression. However, if experimentation shows that 1240 * Zstd is making poor choices, it is possible to override that choice with 1241 * this enum. 1242 */ 1243 ZSTD_dictDefaultAttach = 0, /* Use the default heuristic. */ 1244 ZSTD_dictForceAttach = 1, /* Never copy the dictionary. */ 1245 ZSTD_dictForceCopy = 2, /* Always copy the dictionary. */ 1246 ZSTD_dictForceLoad = 3 /* Always reload the dictionary */ 1247 } ZSTD_dictAttachPref_e; 1248 1249 typedef enum { 1250 ZSTD_lcm_auto = 0, /*< Automatically determine the compression mode based on the compression level. 1251 * Negative compression levels will be uncompressed, and positive compression 1252 * levels will be compressed. */ 1253 ZSTD_lcm_huffman = 1, /*< Always attempt Huffman compression. Uncompressed literals will still be 1254 * emitted if Huffman compression is not profitable. */ 1255 ZSTD_lcm_uncompressed = 2 /*< Always emit uncompressed literals. */ 1256 } ZSTD_literalCompressionMode_e; 1257 1258 1259 /* ************************************* 1260 * Frame size functions 1261 ***************************************/ 1262 1263 /*! ZSTD_findDecompressedSize() : 1264 * `src` should point to the start of a series of ZSTD encoded and/or skippable frames 1265 * `srcSize` must be the _exact_ size of this series 1266 * (i.e. there should be a frame boundary at `src + srcSize`) 1267 * @return : - decompressed size of all data in all successive frames 1268 * - if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN 1269 * - if an error occurred: ZSTD_CONTENTSIZE_ERROR 1270 * 1271 * note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode. 1272 * When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size. 1273 * In which case, it's necessary to use streaming mode to decompress data. 1274 * note 2 : decompressed size is always present when compression is done with ZSTD_compress() 1275 * note 3 : decompressed size can be very large (64-bits value), 1276 * potentially larger than what local system can handle as a single memory segment. 1277 * In which case, it's necessary to use streaming mode to decompress data. 1278 * note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified. 1279 * Always ensure result fits within application's authorized limits. 1280 * Each application can set its own limits. 1281 * note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to 1282 * read each contained frame header. This is fast as most of the data is skipped, 1283 * however it does mean that all frame data must be present and valid. */ 1284 ZSTDLIB_API unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize); 1285 1286 /*! ZSTD_decompressBound() : 1287 * `src` should point to the start of a series of ZSTD encoded and/or skippable frames 1288 * `srcSize` must be the _exact_ size of this series 1289 * (i.e. there should be a frame boundary at `src + srcSize`) 1290 * @return : - upper-bound for the decompressed size of all data in all successive frames 1291 * - if an error occurred: ZSTD_CONTENTSIZE_ERROR 1292 * 1293 * note 1 : an error can occur if `src` contains an invalid or incorrectly formatted frame. 1294 * note 2 : the upper-bound is exact when the decompressed size field is available in every ZSTD encoded frame of `src`. 1295 * in this case, `ZSTD_findDecompressedSize` and `ZSTD_decompressBound` return the same value. 1296 * note 3 : when the decompressed size field isn't available, the upper-bound for that frame is calculated by: 1297 * upper-bound = # blocks * min(128 KB, Window_Size) 1298 */ 1299 ZSTDLIB_API unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize); 1300 1301 /*! ZSTD_frameHeaderSize() : 1302 * srcSize must be >= ZSTD_FRAMEHEADERSIZE_PREFIX. 1303 * @return : size of the Frame Header, 1304 * or an error code (if srcSize is too small) */ 1305 ZSTDLIB_API size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize); 1306 1307 typedef enum { 1308 ZSTD_sf_noBlockDelimiters = 0, /* Representation of ZSTD_Sequence has no block delimiters, sequences only */ 1309 ZSTD_sf_explicitBlockDelimiters = 1 /* Representation of ZSTD_Sequence contains explicit block delimiters */ 1310 } ZSTD_sequenceFormat_e; 1311 1312 /*! ZSTD_generateSequences() : 1313 * Generate sequences using ZSTD_compress2, given a source buffer. 1314 * 1315 * Each block will end with a dummy sequence 1316 * with offset == 0, matchLength == 0, and litLength == length of last literals. 1317 * litLength may be == 0, and if so, then the sequence of (of: 0 ml: 0 ll: 0) 1318 * simply acts as a block delimiter. 1319 * 1320 * zc can be used to insert custom compression params. 1321 * This function invokes ZSTD_compress2 1322 * 1323 * The output of this function can be fed into ZSTD_compressSequences() with CCtx 1324 * setting of ZSTD_c_blockDelimiters as ZSTD_sf_explicitBlockDelimiters 1325 * @return : number of sequences generated 1326 */ 1327 1328 ZSTDLIB_API size_t ZSTD_generateSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs, 1329 size_t outSeqsSize, const void* src, size_t srcSize); 1330 1331 /*! ZSTD_mergeBlockDelimiters() : 1332 * Given an array of ZSTD_Sequence, remove all sequences that represent block delimiters/last literals 1333 * by merging them into into the literals of the next sequence. 1334 * 1335 * As such, the final generated result has no explicit representation of block boundaries, 1336 * and the final last literals segment is not represented in the sequences. 1337 * 1338 * The output of this function can be fed into ZSTD_compressSequences() with CCtx 1339 * setting of ZSTD_c_blockDelimiters as ZSTD_sf_noBlockDelimiters 1340 * @return : number of sequences left after merging 1341 */ 1342 ZSTDLIB_API size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, size_t seqsSize); 1343 1344 /*! ZSTD_compressSequences() : 1345 * Compress an array of ZSTD_Sequence, generated from the original source buffer, into dst. 1346 * If a dictionary is included, then the cctx should reference the dict. (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.) 1347 * The entire source is compressed into a single frame. 1348 * 1349 * The compression behavior changes based on cctx params. In particular: 1350 * If ZSTD_c_blockDelimiters == ZSTD_sf_noBlockDelimiters, the array of ZSTD_Sequence is expected to contain 1351 * no block delimiters (defined in ZSTD_Sequence). Block boundaries are roughly determined based on 1352 * the block size derived from the cctx, and sequences may be split. This is the default setting. 1353 * 1354 * If ZSTD_c_blockDelimiters == ZSTD_sf_explicitBlockDelimiters, the array of ZSTD_Sequence is expected to contain 1355 * block delimiters (defined in ZSTD_Sequence). Behavior is undefined if no block delimiters are provided. 1356 * 1357 * If ZSTD_c_validateSequences == 0, this function will blindly accept the sequences provided. Invalid sequences cause undefined 1358 * behavior. If ZSTD_c_validateSequences == 1, then if sequence is invalid (see doc/zstd_compression_format.md for 1359 * specifics regarding offset/matchlength requirements) then the function will bail out and return an error. 1360 * 1361 * In addition to the two adjustable experimental params, there are other important cctx params. 1362 * - ZSTD_c_minMatch MUST be set as less than or equal to the smallest match generated by the match finder. It has a minimum value of ZSTD_MINMATCH_MIN. 1363 * - ZSTD_c_compressionLevel accordingly adjusts the strength of the entropy coder, as it would in typical compression. 1364 * - ZSTD_c_windowLog affects offset validation: this function will return an error at higher debug levels if a provided offset 1365 * is larger than what the spec allows for a given window log and dictionary (if present). See: doc/zstd_compression_format.md 1366 * 1367 * Note: Repcodes are, as of now, always re-calculated within this function, so ZSTD_Sequence::rep is unused. 1368 * Note 2: Once we integrate ability to ingest repcodes, the explicit block delims mode must respect those repcodes exactly, 1369 * and cannot emit an RLE block that disagrees with the repcode history 1370 * @return : final compressed size or a ZSTD error. 1371 */ 1372 ZSTDLIB_API size_t ZSTD_compressSequences(ZSTD_CCtx* const cctx, void* dst, size_t dstSize, 1373 const ZSTD_Sequence* inSeqs, size_t inSeqsSize, 1374 const void* src, size_t srcSize); 1375 1376 1377 /*! ZSTD_writeSkippableFrame() : 1378 * Generates a zstd skippable frame containing data given by src, and writes it to dst buffer. 1379 * 1380 * Skippable frames begin with a a 4-byte magic number. There are 16 possible choices of magic number, 1381 * ranging from ZSTD_MAGIC_SKIPPABLE_START to ZSTD_MAGIC_SKIPPABLE_START+15. 1382 * As such, the parameter magicVariant controls the exact skippable frame magic number variant used, so 1383 * the magic number used will be ZSTD_MAGIC_SKIPPABLE_START + magicVariant. 1384 * 1385 * Returns an error if destination buffer is not large enough, if the source size is not representable 1386 * with a 4-byte unsigned int, or if the parameter magicVariant is greater than 15 (and therefore invalid). 1387 * 1388 * @return : number of bytes written or a ZSTD error. 1389 */ 1390 ZSTDLIB_API size_t ZSTD_writeSkippableFrame(void* dst, size_t dstCapacity, 1391 const void* src, size_t srcSize, unsigned magicVariant); 1392 1393 1394 /* ************************************* 1395 * Memory management 1396 ***************************************/ 1397 1398 /*! ZSTD_estimate*() : 1399 * These functions make it possible to estimate memory usage 1400 * of a future {D,C}Ctx, before its creation. 1401 * 1402 * ZSTD_estimateCCtxSize() will provide a memory budget large enough 1403 * for any compression level up to selected one. 1404 * Note : Unlike ZSTD_estimateCStreamSize*(), this estimate 1405 * does not include space for a window buffer. 1406 * Therefore, the estimation is only guaranteed for single-shot compressions, not streaming. 1407 * The estimate will assume the input may be arbitrarily large, 1408 * which is the worst case. 1409 * 1410 * When srcSize can be bound by a known and rather "small" value, 1411 * this fact can be used to provide a tighter estimation 1412 * because the CCtx compression context will need less memory. 1413 * This tighter estimation can be provided by more advanced functions 1414 * ZSTD_estimateCCtxSize_usingCParams(), which can be used in tandem with ZSTD_getCParams(), 1415 * and ZSTD_estimateCCtxSize_usingCCtxParams(), which can be used in tandem with ZSTD_CCtxParams_setParameter(). 1416 * Both can be used to estimate memory using custom compression parameters and arbitrary srcSize limits. 1417 * 1418 * Note 2 : only single-threaded compression is supported. 1419 * ZSTD_estimateCCtxSize_usingCCtxParams() will return an error code if ZSTD_c_nbWorkers is >= 1. 1420 */ 1421 ZSTDLIB_API size_t ZSTD_estimateCCtxSize(int compressionLevel); 1422 ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams); 1423 ZSTDLIB_API size_t ZSTD_estimateCCtxSize_usingCCtxParams(const ZSTD_CCtx_params* params); 1424 ZSTDLIB_API size_t ZSTD_estimateDCtxSize(void); 1425 1426 /*! ZSTD_estimateCStreamSize() : 1427 * ZSTD_estimateCStreamSize() will provide a budget large enough for any compression level up to selected one. 1428 * It will also consider src size to be arbitrarily "large", which is worst case. 1429 * If srcSize is known to always be small, ZSTD_estimateCStreamSize_usingCParams() can provide a tighter estimation. 1430 * ZSTD_estimateCStreamSize_usingCParams() can be used in tandem with ZSTD_getCParams() to create cParams from compressionLevel. 1431 * 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. 1432 * Note : CStream size estimation is only correct for single-threaded compression. 1433 * ZSTD_DStream memory budget depends on window Size. 1434 * This information can be passed manually, using ZSTD_estimateDStreamSize, 1435 * or deducted from a valid frame Header, using ZSTD_estimateDStreamSize_fromFrame(); 1436 * Note : if streaming is init with function ZSTD_init?Stream_usingDict(), 1437 * an internal ?Dict will be created, which additional size is not estimated here. 1438 * In this case, get total size by adding ZSTD_estimate?DictSize */ 1439 ZSTDLIB_API size_t ZSTD_estimateCStreamSize(int compressionLevel); 1440 ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCParams(ZSTD_compressionParameters cParams); 1441 ZSTDLIB_API size_t ZSTD_estimateCStreamSize_usingCCtxParams(const ZSTD_CCtx_params* params); 1442 ZSTDLIB_API size_t ZSTD_estimateDStreamSize(size_t windowSize); 1443 ZSTDLIB_API size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize); 1444 1445 /*! ZSTD_estimate?DictSize() : 1446 * ZSTD_estimateCDictSize() will bet that src size is relatively "small", and content is copied, like ZSTD_createCDict(). 1447 * ZSTD_estimateCDictSize_advanced() makes it possible to control compression parameters precisely, like ZSTD_createCDict_advanced(). 1448 * Note : dictionaries created by reference (`ZSTD_dlm_byRef`) are logically smaller. 1449 */ 1450 ZSTDLIB_API size_t ZSTD_estimateCDictSize(size_t dictSize, int compressionLevel); 1451 ZSTDLIB_API size_t ZSTD_estimateCDictSize_advanced(size_t dictSize, ZSTD_compressionParameters cParams, ZSTD_dictLoadMethod_e dictLoadMethod); 1452 ZSTDLIB_API size_t ZSTD_estimateDDictSize(size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod); 1453 1454 /*! ZSTD_initStatic*() : 1455 * Initialize an object using a pre-allocated fixed-size buffer. 1456 * workspace: The memory area to emplace the object into. 1457 * Provided pointer *must be 8-bytes aligned*. 1458 * Buffer must outlive object. 1459 * workspaceSize: Use ZSTD_estimate*Size() to determine 1460 * how large workspace must be to support target scenario. 1461 * @return : pointer to object (same address as workspace, just different type), 1462 * or NULL if error (size too small, incorrect alignment, etc.) 1463 * Note : zstd will never resize nor malloc() when using a static buffer. 1464 * If the object requires more memory than available, 1465 * zstd will just error out (typically ZSTD_error_memory_allocation). 1466 * Note 2 : there is no corresponding "free" function. 1467 * Since workspace is allocated externally, it must be freed externally too. 1468 * Note 3 : cParams : use ZSTD_getCParams() to convert a compression level 1469 * into its associated cParams. 1470 * Limitation 1 : currently not compatible with internal dictionary creation, triggered by 1471 * ZSTD_CCtx_loadDictionary(), ZSTD_initCStream_usingDict() or ZSTD_initDStream_usingDict(). 1472 * Limitation 2 : static cctx currently not compatible with multi-threading. 1473 * Limitation 3 : static dctx is incompatible with legacy support. 1474 */ 1475 ZSTDLIB_API ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize); 1476 ZSTDLIB_API ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize); /*< same as ZSTD_initStaticCCtx() */ 1477 1478 ZSTDLIB_API ZSTD_DCtx* ZSTD_initStaticDCtx(void* workspace, size_t workspaceSize); 1479 ZSTDLIB_API ZSTD_DStream* ZSTD_initStaticDStream(void* workspace, size_t workspaceSize); /*< same as ZSTD_initStaticDCtx() */ 1480 1481 ZSTDLIB_API const ZSTD_CDict* ZSTD_initStaticCDict( 1482 void* workspace, size_t workspaceSize, 1483 const void* dict, size_t dictSize, 1484 ZSTD_dictLoadMethod_e dictLoadMethod, 1485 ZSTD_dictContentType_e dictContentType, 1486 ZSTD_compressionParameters cParams); 1487 1488 ZSTDLIB_API const ZSTD_DDict* ZSTD_initStaticDDict( 1489 void* workspace, size_t workspaceSize, 1490 const void* dict, size_t dictSize, 1491 ZSTD_dictLoadMethod_e dictLoadMethod, 1492 ZSTD_dictContentType_e dictContentType); 1493 1494 1495 /*! Custom memory allocation : 1496 * These prototypes make it possible to pass your own allocation/free functions. 1497 * ZSTD_customMem is provided at creation time, using ZSTD_create*_advanced() variants listed below. 1498 * All allocation/free operations will be completed using these custom variants instead of regular <stdlib.h> ones. 1499 */ 1500 typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size); 1501 typedef void (*ZSTD_freeFunction) (void* opaque, void* address); 1502 typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem; 1503 static 1504 __attribute__((__unused__)) 1505 ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; /*< this constant defers to stdlib's functions */ 1506 1507 ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem); 1508 ZSTDLIB_API ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem); 1509 ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem); 1510 ZSTDLIB_API ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem); 1511 1512 ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, 1513 ZSTD_dictLoadMethod_e dictLoadMethod, 1514 ZSTD_dictContentType_e dictContentType, 1515 ZSTD_compressionParameters cParams, 1516 ZSTD_customMem customMem); 1517 1518 /* ! Thread pool : 1519 * These prototypes make it possible to share a thread pool among multiple compression contexts. 1520 * This can limit resources for applications with multiple threads where each one uses 1521 * a threaded compression mode (via ZSTD_c_nbWorkers parameter). 1522 * ZSTD_createThreadPool creates a new thread pool with a given number of threads. 1523 * Note that the lifetime of such pool must exist while being used. 1524 * ZSTD_CCtx_refThreadPool assigns a thread pool to a context (use NULL argument value 1525 * to use an internal thread pool). 1526 * ZSTD_freeThreadPool frees a thread pool, accepts NULL pointer. 1527 */ 1528 typedef struct POOL_ctx_s ZSTD_threadPool; 1529 ZSTDLIB_API ZSTD_threadPool* ZSTD_createThreadPool(size_t numThreads); 1530 ZSTDLIB_API void ZSTD_freeThreadPool (ZSTD_threadPool* pool); /* accept NULL pointer */ 1531 ZSTDLIB_API size_t ZSTD_CCtx_refThreadPool(ZSTD_CCtx* cctx, ZSTD_threadPool* pool); 1532 1533 1534 /* 1535 * This API is temporary and is expected to change or disappear in the future! 1536 */ 1537 ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced2( 1538 const void* dict, size_t dictSize, 1539 ZSTD_dictLoadMethod_e dictLoadMethod, 1540 ZSTD_dictContentType_e dictContentType, 1541 const ZSTD_CCtx_params* cctxParams, 1542 ZSTD_customMem customMem); 1543 1544 ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced( 1545 const void* dict, size_t dictSize, 1546 ZSTD_dictLoadMethod_e dictLoadMethod, 1547 ZSTD_dictContentType_e dictContentType, 1548 ZSTD_customMem customMem); 1549 1550 1551 /* ************************************* 1552 * Advanced compression functions 1553 ***************************************/ 1554 1555 /*! ZSTD_createCDict_byReference() : 1556 * Create a digested dictionary for compression 1557 * Dictionary content is just referenced, not duplicated. 1558 * As a consequence, `dictBuffer` **must** outlive CDict, 1559 * and its content must remain unmodified throughout the lifetime of CDict. 1560 * note: equivalent to ZSTD_createCDict_advanced(), with dictLoadMethod==ZSTD_dlm_byRef */ 1561 ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel); 1562 1563 /*! ZSTD_getDictID_fromCDict() : 1564 * Provides the dictID of the dictionary loaded into `cdict`. 1565 * If @return == 0, the dictionary is not conformant to Zstandard specification, or empty. 1566 * Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */ 1567 ZSTDLIB_API unsigned ZSTD_getDictID_fromCDict(const ZSTD_CDict* cdict); 1568 1569 /*! ZSTD_getCParams() : 1570 * @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize. 1571 * `estimatedSrcSize` value is optional, select 0 if not known */ 1572 ZSTDLIB_API ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); 1573 1574 /*! ZSTD_getParams() : 1575 * same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of sub-component `ZSTD_compressionParameters`. 1576 * All fields of `ZSTD_frameParameters` are set to default : contentSize=1, checksum=0, noDictID=0 */ 1577 ZSTDLIB_API ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); 1578 1579 /*! ZSTD_checkCParams() : 1580 * Ensure param values remain within authorized range. 1581 * @return 0 on success, or an error code (can be checked with ZSTD_isError()) */ 1582 ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params); 1583 1584 /*! ZSTD_adjustCParams() : 1585 * optimize params for a given `srcSize` and `dictSize`. 1586 * `srcSize` can be unknown, in which case use ZSTD_CONTENTSIZE_UNKNOWN. 1587 * `dictSize` must be `0` when there is no dictionary. 1588 * cPar can be invalid : all parameters will be clamped within valid range in the @return struct. 1589 * This function never fails (wide contract) */ 1590 ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize); 1591 1592 /*! ZSTD_compress_advanced() : 1593 * Note : this function is now DEPRECATED. 1594 * It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_setParameter() and other parameter setters. 1595 * This prototype will be marked as deprecated and generate compilation warning on reaching v1.5.x */ 1596 ZSTDLIB_API size_t ZSTD_compress_advanced(ZSTD_CCtx* cctx, 1597 void* dst, size_t dstCapacity, 1598 const void* src, size_t srcSize, 1599 const void* dict,size_t dictSize, 1600 ZSTD_parameters params); 1601 1602 /*! ZSTD_compress_usingCDict_advanced() : 1603 * Note : this function is now REDUNDANT. 1604 * It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_loadDictionary() and other parameter setters. 1605 * This prototype will be marked as deprecated and generate compilation warning in some future version */ 1606 ZSTDLIB_API size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx, 1607 void* dst, size_t dstCapacity, 1608 const void* src, size_t srcSize, 1609 const ZSTD_CDict* cdict, 1610 ZSTD_frameParameters fParams); 1611 1612 1613 /*! ZSTD_CCtx_loadDictionary_byReference() : 1614 * Same as ZSTD_CCtx_loadDictionary(), but dictionary content is referenced, instead of being copied into CCtx. 1615 * It saves some memory, but also requires that `dict` outlives its usage within `cctx` */ 1616 ZSTDLIB_API size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize); 1617 1618 /*! ZSTD_CCtx_loadDictionary_advanced() : 1619 * Same as ZSTD_CCtx_loadDictionary(), but gives finer control over 1620 * how to load the dictionary (by copy ? by reference ?) 1621 * and how to interpret it (automatic ? force raw mode ? full mode only ?) */ 1622 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); 1623 1624 /*! ZSTD_CCtx_refPrefix_advanced() : 1625 * Same as ZSTD_CCtx_refPrefix(), but gives finer control over 1626 * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */ 1627 ZSTDLIB_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType); 1628 1629 /* === experimental parameters === */ 1630 /* these parameters can be used with ZSTD_setParameter() 1631 * they are not guaranteed to remain supported in the future */ 1632 1633 /* Enables rsyncable mode, 1634 * which makes compressed files more rsync friendly 1635 * by adding periodic synchronization points to the compressed data. 1636 * The target average block size is ZSTD_c_jobSize / 2. 1637 * It's possible to modify the job size to increase or decrease 1638 * the granularity of the synchronization point. 1639 * Once the jobSize is smaller than the window size, 1640 * it will result in compression ratio degradation. 1641 * NOTE 1: rsyncable mode only works when multithreading is enabled. 1642 * NOTE 2: rsyncable performs poorly in combination with long range mode, 1643 * since it will decrease the effectiveness of synchronization points, 1644 * though mileage may vary. 1645 * NOTE 3: Rsyncable mode limits maximum compression speed to ~400 MB/s. 1646 * If the selected compression level is already running significantly slower, 1647 * the overall speed won't be significantly impacted. 1648 */ 1649 #define ZSTD_c_rsyncable ZSTD_c_experimentalParam1 1650 1651 /* Select a compression format. 1652 * The value must be of type ZSTD_format_e. 1653 * See ZSTD_format_e enum definition for details */ 1654 #define ZSTD_c_format ZSTD_c_experimentalParam2 1655 1656 /* Force back-reference distances to remain < windowSize, 1657 * even when referencing into Dictionary content (default:0) */ 1658 #define ZSTD_c_forceMaxWindow ZSTD_c_experimentalParam3 1659 1660 /* Controls whether the contents of a CDict 1661 * are used in place, or copied into the working context. 1662 * Accepts values from the ZSTD_dictAttachPref_e enum. 1663 * See the comments on that enum for an explanation of the feature. */ 1664 #define ZSTD_c_forceAttachDict ZSTD_c_experimentalParam4 1665 1666 /* Controls how the literals are compressed (default is auto). 1667 * The value must be of type ZSTD_literalCompressionMode_e. 1668 * See ZSTD_literalCompressionMode_t enum definition for details. 1669 */ 1670 #define ZSTD_c_literalCompressionMode ZSTD_c_experimentalParam5 1671 1672 /* Tries to fit compressed block size to be around targetCBlockSize. 1673 * No target when targetCBlockSize == 0. 1674 * There is no guarantee on compressed block size (default:0) */ 1675 #define ZSTD_c_targetCBlockSize ZSTD_c_experimentalParam6 1676 1677 /* User's best guess of source size. 1678 * Hint is not valid when srcSizeHint == 0. 1679 * There is no guarantee that hint is close to actual source size, 1680 * but compression ratio may regress significantly if guess considerably underestimates */ 1681 #define ZSTD_c_srcSizeHint ZSTD_c_experimentalParam7 1682 1683 /* Controls whether the new and experimental "dedicated dictionary search 1684 * structure" can be used. This feature is still rough around the edges, be 1685 * prepared for surprising behavior! 1686 * 1687 * How to use it: 1688 * 1689 * When using a CDict, whether to use this feature or not is controlled at 1690 * CDict creation, and it must be set in a CCtxParams set passed into that 1691 * construction (via ZSTD_createCDict_advanced2()). A compression will then 1692 * use the feature or not based on how the CDict was constructed; the value of 1693 * this param, set in the CCtx, will have no effect. 1694 * 1695 * However, when a dictionary buffer is passed into a CCtx, such as via 1696 * ZSTD_CCtx_loadDictionary(), this param can be set on the CCtx to control 1697 * whether the CDict that is created internally can use the feature or not. 1698 * 1699 * What it does: 1700 * 1701 * Normally, the internal data structures of the CDict are analogous to what 1702 * would be stored in a CCtx after compressing the contents of a dictionary. 1703 * To an approximation, a compression using a dictionary can then use those 1704 * data structures to simply continue what is effectively a streaming 1705 * compression where the simulated compression of the dictionary left off. 1706 * Which is to say, the search structures in the CDict are normally the same 1707 * format as in the CCtx. 1708 * 1709 * It is possible to do better, since the CDict is not like a CCtx: the search 1710 * structures are written once during CDict creation, and then are only read 1711 * after that, while the search structures in the CCtx are both read and 1712 * written as the compression goes along. This means we can choose a search 1713 * structure for the dictionary that is read-optimized. 1714 * 1715 * This feature enables the use of that different structure. 1716 * 1717 * Note that some of the members of the ZSTD_compressionParameters struct have 1718 * different semantics and constraints in the dedicated search structure. It is 1719 * highly recommended that you simply set a compression level in the CCtxParams 1720 * you pass into the CDict creation call, and avoid messing with the cParams 1721 * directly. 1722 * 1723 * Effects: 1724 * 1725 * This will only have any effect when the selected ZSTD_strategy 1726 * implementation supports this feature. Currently, that's limited to 1727 * ZSTD_greedy, ZSTD_lazy, and ZSTD_lazy2. 1728 * 1729 * Note that this means that the CDict tables can no longer be copied into the 1730 * CCtx, so the dict attachment mode ZSTD_dictForceCopy will no longer be 1731 * useable. The dictionary can only be attached or reloaded. 1732 * 1733 * In general, you should expect compression to be faster--sometimes very much 1734 * so--and CDict creation to be slightly slower. Eventually, we will probably 1735 * make this mode the default. 1736 */ 1737 #define ZSTD_c_enableDedicatedDictSearch ZSTD_c_experimentalParam8 1738 1739 /* ZSTD_c_stableInBuffer 1740 * Experimental parameter. 1741 * Default is 0 == disabled. Set to 1 to enable. 1742 * 1743 * Tells the compressor that the ZSTD_inBuffer will ALWAYS be the same 1744 * between calls, except for the modifications that zstd makes to pos (the 1745 * caller must not modify pos). This is checked by the compressor, and 1746 * compression will fail if it ever changes. This means the only flush 1747 * mode that makes sense is ZSTD_e_end, so zstd will error if ZSTD_e_end 1748 * is not used. The data in the ZSTD_inBuffer in the range [src, src + pos) 1749 * MUST not be modified during compression or you will get data corruption. 1750 * 1751 * When this flag is enabled zstd won't allocate an input window buffer, 1752 * because the user guarantees it can reference the ZSTD_inBuffer until 1753 * the frame is complete. But, it will still allocate an output buffer 1754 * large enough to fit a block (see ZSTD_c_stableOutBuffer). This will also 1755 * avoid the memcpy() from the input buffer to the input window buffer. 1756 * 1757 * NOTE: ZSTD_compressStream2() will error if ZSTD_e_end is not used. 1758 * That means this flag cannot be used with ZSTD_compressStream(). 1759 * 1760 * NOTE: So long as the ZSTD_inBuffer always points to valid memory, using 1761 * this flag is ALWAYS memory safe, and will never access out-of-bounds 1762 * memory. However, compression WILL fail if you violate the preconditions. 1763 * 1764 * WARNING: The data in the ZSTD_inBuffer in the range [dst, dst + pos) MUST 1765 * not be modified during compression or you will get data corruption. This 1766 * is because zstd needs to reference data in the ZSTD_inBuffer to find 1767 * matches. Normally zstd maintains its own window buffer for this purpose, 1768 * but passing this flag tells zstd to use the user provided buffer. 1769 */ 1770 #define ZSTD_c_stableInBuffer ZSTD_c_experimentalParam9 1771 1772 /* ZSTD_c_stableOutBuffer 1773 * Experimental parameter. 1774 * Default is 0 == disabled. Set to 1 to enable. 1775 * 1776 * Tells he compressor that the ZSTD_outBuffer will not be resized between 1777 * calls. Specifically: (out.size - out.pos) will never grow. This gives the 1778 * compressor the freedom to say: If the compressed data doesn't fit in the 1779 * output buffer then return ZSTD_error_dstSizeTooSmall. This allows us to 1780 * always decompress directly into the output buffer, instead of decompressing 1781 * into an internal buffer and copying to the output buffer. 1782 * 1783 * When this flag is enabled zstd won't allocate an output buffer, because 1784 * it can write directly to the ZSTD_outBuffer. It will still allocate the 1785 * input window buffer (see ZSTD_c_stableInBuffer). 1786 * 1787 * Zstd will check that (out.size - out.pos) never grows and return an error 1788 * if it does. While not strictly necessary, this should prevent surprises. 1789 */ 1790 #define ZSTD_c_stableOutBuffer ZSTD_c_experimentalParam10 1791 1792 /* ZSTD_c_blockDelimiters 1793 * Default is 0 == ZSTD_sf_noBlockDelimiters. 1794 * 1795 * For use with sequence compression API: ZSTD_compressSequences(). 1796 * 1797 * Designates whether or not the given array of ZSTD_Sequence contains block delimiters 1798 * and last literals, which are defined as sequences with offset == 0 and matchLength == 0. 1799 * See the definition of ZSTD_Sequence for more specifics. 1800 */ 1801 #define ZSTD_c_blockDelimiters ZSTD_c_experimentalParam11 1802 1803 /* ZSTD_c_validateSequences 1804 * Default is 0 == disabled. Set to 1 to enable sequence validation. 1805 * 1806 * For use with sequence compression API: ZSTD_compressSequences(). 1807 * Designates whether or not we validate sequences provided to ZSTD_compressSequences() 1808 * during function execution. 1809 * 1810 * Without validation, providing a sequence that does not conform to the zstd spec will cause 1811 * undefined behavior, and may produce a corrupted block. 1812 * 1813 * With validation enabled, a if sequence is invalid (see doc/zstd_compression_format.md for 1814 * specifics regarding offset/matchlength requirements) then the function will bail out and 1815 * return an error. 1816 * 1817 */ 1818 #define ZSTD_c_validateSequences ZSTD_c_experimentalParam12 1819 1820 /*! ZSTD_CCtx_getParameter() : 1821 * Get the requested compression parameter value, selected by enum ZSTD_cParameter, 1822 * and store it into int* value. 1823 * @return : 0, or an error code (which can be tested with ZSTD_isError()). 1824 */ 1825 ZSTDLIB_API size_t ZSTD_CCtx_getParameter(const ZSTD_CCtx* cctx, ZSTD_cParameter param, int* value); 1826 1827 1828 /*! ZSTD_CCtx_params : 1829 * Quick howto : 1830 * - ZSTD_createCCtxParams() : Create a ZSTD_CCtx_params structure 1831 * - ZSTD_CCtxParams_setParameter() : Push parameters one by one into 1832 * an existing ZSTD_CCtx_params structure. 1833 * This is similar to 1834 * ZSTD_CCtx_setParameter(). 1835 * - ZSTD_CCtx_setParametersUsingCCtxParams() : Apply parameters to 1836 * an existing CCtx. 1837 * These parameters will be applied to 1838 * all subsequent frames. 1839 * - ZSTD_compressStream2() : Do compression using the CCtx. 1840 * - ZSTD_freeCCtxParams() : Free the memory, accept NULL pointer. 1841 * 1842 * This can be used with ZSTD_estimateCCtxSize_advanced_usingCCtxParams() 1843 * for static allocation of CCtx for single-threaded compression. 1844 */ 1845 ZSTDLIB_API ZSTD_CCtx_params* ZSTD_createCCtxParams(void); 1846 ZSTDLIB_API size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params); /* accept NULL pointer */ 1847 1848 /*! ZSTD_CCtxParams_reset() : 1849 * Reset params to default values. 1850 */ 1851 ZSTDLIB_API size_t ZSTD_CCtxParams_reset(ZSTD_CCtx_params* params); 1852 1853 /*! ZSTD_CCtxParams_init() : 1854 * Initializes the compression parameters of cctxParams according to 1855 * compression level. All other parameters are reset to their default values. 1856 */ 1857 ZSTDLIB_API size_t ZSTD_CCtxParams_init(ZSTD_CCtx_params* cctxParams, int compressionLevel); 1858 1859 /*! ZSTD_CCtxParams_init_advanced() : 1860 * Initializes the compression and frame parameters of cctxParams according to 1861 * params. All other parameters are reset to their default values. 1862 */ 1863 ZSTDLIB_API size_t ZSTD_CCtxParams_init_advanced(ZSTD_CCtx_params* cctxParams, ZSTD_parameters params); 1864 1865 /*! ZSTD_CCtxParams_setParameter() : 1866 * Similar to ZSTD_CCtx_setParameter. 1867 * Set one compression parameter, selected by enum ZSTD_cParameter. 1868 * Parameters must be applied to a ZSTD_CCtx using 1869 * ZSTD_CCtx_setParametersUsingCCtxParams(). 1870 * @result : a code representing success or failure (which can be tested with 1871 * ZSTD_isError()). 1872 */ 1873 ZSTDLIB_API size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int value); 1874 1875 /*! ZSTD_CCtxParams_getParameter() : 1876 * Similar to ZSTD_CCtx_getParameter. 1877 * Get the requested value of one compression parameter, selected by enum ZSTD_cParameter. 1878 * @result : 0, or an error code (which can be tested with ZSTD_isError()). 1879 */ 1880 ZSTDLIB_API size_t ZSTD_CCtxParams_getParameter(const ZSTD_CCtx_params* params, ZSTD_cParameter param, int* value); 1881 1882 /*! ZSTD_CCtx_setParametersUsingCCtxParams() : 1883 * Apply a set of ZSTD_CCtx_params to the compression context. 1884 * This can be done even after compression is started, 1885 * if nbWorkers==0, this will have no impact until a new compression is started. 1886 * if nbWorkers>=1, new parameters will be picked up at next job, 1887 * with a few restrictions (windowLog, pledgedSrcSize, nbWorkers, jobSize, and overlapLog are not updated). 1888 */ 1889 ZSTDLIB_API size_t ZSTD_CCtx_setParametersUsingCCtxParams( 1890 ZSTD_CCtx* cctx, const ZSTD_CCtx_params* params); 1891 1892 /*! ZSTD_compressStream2_simpleArgs() : 1893 * Same as ZSTD_compressStream2(), 1894 * but using only integral types as arguments. 1895 * This variant might be helpful for binders from dynamic languages 1896 * which have troubles handling structures containing memory pointers. 1897 */ 1898 ZSTDLIB_API size_t ZSTD_compressStream2_simpleArgs ( 1899 ZSTD_CCtx* cctx, 1900 void* dst, size_t dstCapacity, size_t* dstPos, 1901 const void* src, size_t srcSize, size_t* srcPos, 1902 ZSTD_EndDirective endOp); 1903 1904 1905 /* ************************************* 1906 * Advanced decompression functions 1907 ***************************************/ 1908 1909 /*! ZSTD_isFrame() : 1910 * Tells if the content of `buffer` starts with a valid Frame Identifier. 1911 * Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0. 1912 * Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled. 1913 * Note 3 : Skippable Frame Identifiers are considered valid. */ 1914 ZSTDLIB_API unsigned ZSTD_isFrame(const void* buffer, size_t size); 1915 1916 /*! ZSTD_createDDict_byReference() : 1917 * Create a digested dictionary, ready to start decompression operation without startup delay. 1918 * Dictionary content is referenced, and therefore stays in dictBuffer. 1919 * It is important that dictBuffer outlives DDict, 1920 * it must remain read accessible throughout the lifetime of DDict */ 1921 ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize); 1922 1923 /*! ZSTD_DCtx_loadDictionary_byReference() : 1924 * Same as ZSTD_DCtx_loadDictionary(), 1925 * but references `dict` content instead of copying it into `dctx`. 1926 * This saves memory if `dict` remains around., 1927 * However, it's imperative that `dict` remains accessible (and unmodified) while being used, so it must outlive decompression. */ 1928 ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); 1929 1930 /*! ZSTD_DCtx_loadDictionary_advanced() : 1931 * Same as ZSTD_DCtx_loadDictionary(), 1932 * but gives direct control over 1933 * how to load the dictionary (by copy ? by reference ?) 1934 * and how to interpret it (automatic ? force raw mode ? full mode only ?). */ 1935 ZSTDLIB_API size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType); 1936 1937 /*! ZSTD_DCtx_refPrefix_advanced() : 1938 * Same as ZSTD_DCtx_refPrefix(), but gives finer control over 1939 * how to interpret prefix content (automatic ? force raw mode (default) ? full mode only ?) */ 1940 ZSTDLIB_API size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType); 1941 1942 /*! ZSTD_DCtx_setMaxWindowSize() : 1943 * Refuses allocating internal buffers for frames requiring a window size larger than provided limit. 1944 * This protects a decoder context from reserving too much memory for itself (potential attack scenario). 1945 * This parameter is only useful in streaming mode, since no internal buffer is allocated in single-pass mode. 1946 * By default, a decompression context accepts all window sizes <= (1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT) 1947 * @return : 0, or an error code (which can be tested using ZSTD_isError()). 1948 */ 1949 ZSTDLIB_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize); 1950 1951 /*! ZSTD_DCtx_getParameter() : 1952 * Get the requested decompression parameter value, selected by enum ZSTD_dParameter, 1953 * and store it into int* value. 1954 * @return : 0, or an error code (which can be tested with ZSTD_isError()). 1955 */ 1956 ZSTDLIB_API size_t ZSTD_DCtx_getParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int* value); 1957 1958 /* ZSTD_d_format 1959 * experimental parameter, 1960 * allowing selection between ZSTD_format_e input compression formats 1961 */ 1962 #define ZSTD_d_format ZSTD_d_experimentalParam1 1963 /* ZSTD_d_stableOutBuffer 1964 * Experimental parameter. 1965 * Default is 0 == disabled. Set to 1 to enable. 1966 * 1967 * Tells the decompressor that the ZSTD_outBuffer will ALWAYS be the same 1968 * between calls, except for the modifications that zstd makes to pos (the 1969 * caller must not modify pos). This is checked by the decompressor, and 1970 * decompression will fail if it ever changes. Therefore the ZSTD_outBuffer 1971 * MUST be large enough to fit the entire decompressed frame. This will be 1972 * checked when the frame content size is known. The data in the ZSTD_outBuffer 1973 * in the range [dst, dst + pos) MUST not be modified during decompression 1974 * or you will get data corruption. 1975 * 1976 * When this flags is enabled zstd won't allocate an output buffer, because 1977 * it can write directly to the ZSTD_outBuffer, but it will still allocate 1978 * an input buffer large enough to fit any compressed block. This will also 1979 * avoid the memcpy() from the internal output buffer to the ZSTD_outBuffer. 1980 * If you need to avoid the input buffer allocation use the buffer-less 1981 * streaming API. 1982 * 1983 * NOTE: So long as the ZSTD_outBuffer always points to valid memory, using 1984 * this flag is ALWAYS memory safe, and will never access out-of-bounds 1985 * memory. However, decompression WILL fail if you violate the preconditions. 1986 * 1987 * WARNING: The data in the ZSTD_outBuffer in the range [dst, dst + pos) MUST 1988 * not be modified during decompression or you will get data corruption. This 1989 * is because zstd needs to reference data in the ZSTD_outBuffer to regenerate 1990 * matches. Normally zstd maintains its own buffer for this purpose, but passing 1991 * this flag tells zstd to use the user provided buffer. 1992 */ 1993 #define ZSTD_d_stableOutBuffer ZSTD_d_experimentalParam2 1994 1995 /* ZSTD_d_forceIgnoreChecksum 1996 * Experimental parameter. 1997 * Default is 0 == disabled. Set to 1 to enable 1998 * 1999 * Tells the decompressor to skip checksum validation during decompression, regardless 2000 * of whether checksumming was specified during compression. This offers some 2001 * slight performance benefits, and may be useful for debugging. 2002 * Param has values of type ZSTD_forceIgnoreChecksum_e 2003 */ 2004 #define ZSTD_d_forceIgnoreChecksum ZSTD_d_experimentalParam3 2005 2006 /* ZSTD_d_refMultipleDDicts 2007 * Experimental parameter. 2008 * Default is 0 == disabled. Set to 1 to enable 2009 * 2010 * If enabled and dctx is allocated on the heap, then additional memory will be allocated 2011 * to store references to multiple ZSTD_DDict. That is, multiple calls of ZSTD_refDDict() 2012 * using a given ZSTD_DCtx, rather than overwriting the previous DDict reference, will instead 2013 * store all references. At decompression time, the appropriate dictID is selected 2014 * from the set of DDicts based on the dictID in the frame. 2015 * 2016 * Usage is simply calling ZSTD_refDDict() on multiple dict buffers. 2017 * 2018 * Param has values of byte ZSTD_refMultipleDDicts_e 2019 * 2020 * WARNING: Enabling this parameter and calling ZSTD_DCtx_refDDict(), will trigger memory 2021 * allocation for the hash table. ZSTD_freeDCtx() also frees this memory. 2022 * Memory is allocated as per ZSTD_DCtx::customMem. 2023 * 2024 * Although this function allocates memory for the table, the user is still responsible for 2025 * memory management of the underlying ZSTD_DDict* themselves. 2026 */ 2027 #define ZSTD_d_refMultipleDDicts ZSTD_d_experimentalParam4 2028 2029 2030 /*! ZSTD_DCtx_setFormat() : 2031 * Instruct the decoder context about what kind of data to decode next. 2032 * This instruction is mandatory to decode data without a fully-formed header, 2033 * such ZSTD_f_zstd1_magicless for example. 2034 * @return : 0, or an error code (which can be tested using ZSTD_isError()). */ 2035 ZSTDLIB_API size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format); 2036 2037 /*! ZSTD_decompressStream_simpleArgs() : 2038 * Same as ZSTD_decompressStream(), 2039 * but using only integral types as arguments. 2040 * This can be helpful for binders from dynamic languages 2041 * which have troubles handling structures containing memory pointers. 2042 */ 2043 ZSTDLIB_API size_t ZSTD_decompressStream_simpleArgs ( 2044 ZSTD_DCtx* dctx, 2045 void* dst, size_t dstCapacity, size_t* dstPos, 2046 const void* src, size_t srcSize, size_t* srcPos); 2047 2048 2049 /* ****************************************************************** 2050 * Advanced streaming functions 2051 * Warning : most of these functions are now redundant with the Advanced API. 2052 * Once Advanced API reaches "stable" status, 2053 * redundant functions will be deprecated, and then at some point removed. 2054 ********************************************************************/ 2055 2056 /*===== Advanced Streaming compression functions =====*/ 2057 2058 /*! ZSTD_initCStream_srcSize() : 2059 * This function is deprecated, and equivalent to: 2060 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 2061 * ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any) 2062 * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); 2063 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); 2064 * 2065 * pledgedSrcSize must be correct. If it is not known at init time, use 2066 * ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs, 2067 * "0" also disables frame content size field. It may be enabled in the future. 2068 * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x 2069 */ 2070 ZSTDLIB_API size_t 2071 ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, 2072 int compressionLevel, 2073 unsigned long long pledgedSrcSize); 2074 2075 /*! ZSTD_initCStream_usingDict() : 2076 * This function is deprecated, and is equivalent to: 2077 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 2078 * ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel); 2079 * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize); 2080 * 2081 * Creates of an internal CDict (incompatible with static CCtx), except if 2082 * dict == NULL or dictSize < 8, in which case no dict is used. 2083 * Note: dict is loaded with ZSTD_dct_auto (treated as a full zstd dictionary if 2084 * it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy. 2085 * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x 2086 */ 2087 ZSTDLIB_API size_t 2088 ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, 2089 const void* dict, size_t dictSize, 2090 int compressionLevel); 2091 2092 /*! ZSTD_initCStream_advanced() : 2093 * This function is deprecated, and is approximately equivalent to: 2094 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 2095 * // Pseudocode: Set each zstd parameter and leave the rest as-is. 2096 * for ((param, value) : params) { 2097 * ZSTD_CCtx_setParameter(zcs, param, value); 2098 * } 2099 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); 2100 * ZSTD_CCtx_loadDictionary(zcs, dict, dictSize); 2101 * 2102 * dict is loaded with ZSTD_dct_auto and ZSTD_dlm_byCopy. 2103 * pledgedSrcSize must be correct. 2104 * If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN. 2105 * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x 2106 */ 2107 ZSTDLIB_API size_t 2108 ZSTD_initCStream_advanced(ZSTD_CStream* zcs, 2109 const void* dict, size_t dictSize, 2110 ZSTD_parameters params, 2111 unsigned long long pledgedSrcSize); 2112 2113 /*! ZSTD_initCStream_usingCDict() : 2114 * This function is deprecated, and equivalent to: 2115 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 2116 * ZSTD_CCtx_refCDict(zcs, cdict); 2117 * 2118 * note : cdict will just be referenced, and must outlive compression session 2119 * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x 2120 */ 2121 ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict); 2122 2123 /*! ZSTD_initCStream_usingCDict_advanced() : 2124 * This function is DEPRECATED, and is approximately equivalent to: 2125 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 2126 * // Pseudocode: Set each zstd frame parameter and leave the rest as-is. 2127 * for ((fParam, value) : fParams) { 2128 * ZSTD_CCtx_setParameter(zcs, fParam, value); 2129 * } 2130 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); 2131 * ZSTD_CCtx_refCDict(zcs, cdict); 2132 * 2133 * same as ZSTD_initCStream_usingCDict(), with control over frame parameters. 2134 * pledgedSrcSize must be correct. If srcSize is not known at init time, use 2135 * value ZSTD_CONTENTSIZE_UNKNOWN. 2136 * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x 2137 */ 2138 ZSTDLIB_API size_t 2139 ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, 2140 const ZSTD_CDict* cdict, 2141 ZSTD_frameParameters fParams, 2142 unsigned long long pledgedSrcSize); 2143 2144 /*! ZSTD_resetCStream() : 2145 * This function is deprecated, and is equivalent to: 2146 * ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only); 2147 * ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize); 2148 * 2149 * start a new frame, using same parameters from previous frame. 2150 * This is typically useful to skip dictionary loading stage, since it will re-use it in-place. 2151 * Note that zcs must be init at least once before using ZSTD_resetCStream(). 2152 * If pledgedSrcSize is not known at reset time, use macro ZSTD_CONTENTSIZE_UNKNOWN. 2153 * If pledgedSrcSize > 0, its value must be correct, as it will be written in header, and controlled at the end. 2154 * For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs, 2155 * but it will change to mean "empty" in future version, so use macro ZSTD_CONTENTSIZE_UNKNOWN instead. 2156 * @return : 0, or an error code (which can be tested using ZSTD_isError()) 2157 * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x 2158 */ 2159 ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); 2160 2161 2162 typedef struct { 2163 unsigned long long ingested; /* nb input bytes read and buffered */ 2164 unsigned long long consumed; /* nb input bytes actually compressed */ 2165 unsigned long long produced; /* nb of compressed bytes generated and buffered */ 2166 unsigned long long flushed; /* nb of compressed bytes flushed : not provided; can be tracked from caller side */ 2167 unsigned currentJobID; /* MT only : latest started job nb */ 2168 unsigned nbActiveWorkers; /* MT only : nb of workers actively compressing at probe time */ 2169 } ZSTD_frameProgression; 2170 2171 /* ZSTD_getFrameProgression() : 2172 * tells how much data has been ingested (read from input) 2173 * consumed (input actually compressed) and produced (output) for current frame. 2174 * Note : (ingested - consumed) is amount of input data buffered internally, not yet compressed. 2175 * Aggregates progression inside active worker threads. 2176 */ 2177 ZSTDLIB_API ZSTD_frameProgression ZSTD_getFrameProgression(const ZSTD_CCtx* cctx); 2178 2179 /*! ZSTD_toFlushNow() : 2180 * Tell how many bytes are ready to be flushed immediately. 2181 * Useful for multithreading scenarios (nbWorkers >= 1). 2182 * Probe the oldest active job, defined as oldest job not yet entirely flushed, 2183 * and check its output buffer. 2184 * @return : amount of data stored in oldest job and ready to be flushed immediately. 2185 * if @return == 0, it means either : 2186 * + there is no active job (could be checked with ZSTD_frameProgression()), or 2187 * + oldest job is still actively compressing data, 2188 * but everything it has produced has also been flushed so far, 2189 * therefore flush speed is limited by production speed of oldest job 2190 * irrespective of the speed of concurrent (and newer) jobs. 2191 */ 2192 ZSTDLIB_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx); 2193 2194 2195 /*===== Advanced Streaming decompression functions =====*/ 2196 2197 /*! 2198 * This function is deprecated, and is equivalent to: 2199 * 2200 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); 2201 * ZSTD_DCtx_loadDictionary(zds, dict, dictSize); 2202 * 2203 * note: no dictionary will be used if dict == NULL or dictSize < 8 2204 * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x 2205 */ 2206 ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); 2207 2208 /*! 2209 * This function is deprecated, and is equivalent to: 2210 * 2211 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); 2212 * ZSTD_DCtx_refDDict(zds, ddict); 2213 * 2214 * note : ddict is referenced, it must outlive decompression session 2215 * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x 2216 */ 2217 ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); 2218 2219 /*! 2220 * This function is deprecated, and is equivalent to: 2221 * 2222 * ZSTD_DCtx_reset(zds, ZSTD_reset_session_only); 2223 * 2224 * re-use decompression parameters from previous init; saves dictionary loading 2225 * Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x 2226 */ 2227 ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds); 2228 2229 2230 /* ******************************************************************* 2231 * Buffer-less and synchronous inner streaming functions 2232 * 2233 * This is an advanced API, giving full control over buffer management, for users which need direct control over memory. 2234 * But it's also a complex one, with several restrictions, documented below. 2235 * Prefer normal streaming API for an easier experience. 2236 ********************************************************************* */ 2237 2238 /* 2239 Buffer-less streaming compression (synchronous mode) 2240 2241 A ZSTD_CCtx object is required to track streaming operations. 2242 Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource. 2243 ZSTD_CCtx object can be re-used multiple times within successive compression operations. 2244 2245 Start by initializing a context. 2246 Use ZSTD_compressBegin(), or ZSTD_compressBegin_usingDict() for dictionary compression, 2247 or ZSTD_compressBegin_advanced(), for finer parameter control. 2248 It's also possible to duplicate a reference context which has already been initialized, using ZSTD_copyCCtx() 2249 2250 Then, consume your input using ZSTD_compressContinue(). 2251 There are some important considerations to keep in mind when using this advanced function : 2252 - ZSTD_compressContinue() has no internal buffer. It uses externally provided buffers only. 2253 - Interface is synchronous : input is consumed entirely and produces 1+ compressed blocks. 2254 - Caller must ensure there is enough space in `dst` to store compressed data under worst case scenario. 2255 Worst case evaluation is provided by ZSTD_compressBound(). 2256 ZSTD_compressContinue() doesn't guarantee recover after a failed compression. 2257 - ZSTD_compressContinue() presumes prior input ***is still accessible and unmodified*** (up to maximum distance size, see WindowLog). 2258 It remembers all previous contiguous blocks, plus one separated memory segment (which can itself consists of multiple contiguous blocks) 2259 - ZSTD_compressContinue() detects that prior input has been overwritten when `src` buffer overlaps. 2260 In which case, it will "discard" the relevant memory section from its history. 2261 2262 Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum. 2263 It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame. 2264 Without last block mark, frames are considered unfinished (hence corrupted) by compliant decoders. 2265 2266 `ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress again. 2267 */ 2268 2269 /*===== Buffer-less streaming compression functions =====*/ 2270 ZSTDLIB_API size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel); 2271 ZSTDLIB_API size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel); 2272 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 */ 2273 ZSTDLIB_API size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); /*< note: fails if cdict==NULL */ 2274 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 */ 2275 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 */ 2276 2277 ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 2278 ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 2279 2280 2281 /* 2282 Buffer-less streaming decompression (synchronous mode) 2283 2284 A ZSTD_DCtx object is required to track streaming operations. 2285 Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it. 2286 A ZSTD_DCtx object can be re-used multiple times. 2287 2288 First typical operation is to retrieve frame parameters, using ZSTD_getFrameHeader(). 2289 Frame header is extracted from the beginning of compressed frame, so providing only the frame's beginning is enough. 2290 Data fragment must be large enough to ensure successful decoding. 2291 `ZSTD_frameHeaderSize_max` bytes is guaranteed to always be large enough. 2292 @result : 0 : successful decoding, the `ZSTD_frameHeader` structure is correctly filled. 2293 >0 : `srcSize` is too small, please provide at least @result bytes on next attempt. 2294 errorCode, which can be tested using ZSTD_isError(). 2295 2296 It fills a ZSTD_frameHeader structure with important information to correctly decode the frame, 2297 such as the dictionary ID, content size, or maximum back-reference distance (`windowSize`). 2298 Note that these values could be wrong, either because of data corruption, or because a 3rd party deliberately spoofs false information. 2299 As a consequence, check that values remain within valid application range. 2300 For example, do not allocate memory blindly, check that `windowSize` is within expectation. 2301 Each application can set its own limits, depending on local restrictions. 2302 For extended interoperability, it is recommended to support `windowSize` of at least 8 MB. 2303 2304 ZSTD_decompressContinue() needs previous data blocks during decompression, up to `windowSize` bytes. 2305 ZSTD_decompressContinue() is very sensitive to contiguity, 2306 if 2 blocks don't follow each other, make sure that either the compressor breaks contiguity at the same place, 2307 or that previous contiguous segment is large enough to properly handle maximum back-reference distance. 2308 There are multiple ways to guarantee this condition. 2309 2310 The most memory efficient way is to use a round buffer of sufficient size. 2311 Sufficient size is determined by invoking ZSTD_decodingBufferSize_min(), 2312 which can @return an error code if required value is too large for current system (in 32-bits mode). 2313 In a round buffer methodology, ZSTD_decompressContinue() decompresses each block next to previous one, 2314 up to the moment there is not enough room left in the buffer to guarantee decoding another full block, 2315 which maximum size is provided in `ZSTD_frameHeader` structure, field `blockSizeMax`. 2316 At which point, decoding can resume from the beginning of the buffer. 2317 Note that already decoded data stored in the buffer should be flushed before being overwritten. 2318 2319 There are alternatives possible, for example using two or more buffers of size `windowSize` each, though they consume more memory. 2320 2321 Finally, if you control the compression process, you can also ignore all buffer size rules, 2322 as long as the encoder and decoder progress in "lock-step", 2323 aka use exactly the same buffer sizes, break contiguity at the same place, etc. 2324 2325 Once buffers are setup, start decompression, with ZSTD_decompressBegin(). 2326 If decompression requires a dictionary, use ZSTD_decompressBegin_usingDict() or ZSTD_decompressBegin_usingDDict(). 2327 2328 Then use ZSTD_nextSrcSizeToDecompress() and ZSTD_decompressContinue() alternatively. 2329 ZSTD_nextSrcSizeToDecompress() tells how many bytes to provide as 'srcSize' to ZSTD_decompressContinue(). 2330 ZSTD_decompressContinue() requires this _exact_ amount of bytes, or it will fail. 2331 2332 @result of ZSTD_decompressContinue() is the number of bytes regenerated within 'dst' (necessarily <= dstCapacity). 2333 It can be zero : it just means ZSTD_decompressContinue() has decoded some metadata item. 2334 It can also be an error code, which can be tested with ZSTD_isError(). 2335 2336 A frame is fully decoded when ZSTD_nextSrcSizeToDecompress() returns zero. 2337 Context can then be reset to start a new decompression. 2338 2339 Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType(). 2340 This information is not required to properly decode a frame. 2341 2342 == Special case : skippable frames == 2343 2344 Skippable frames allow integration of user-defined data into a flow of concatenated frames. 2345 Skippable frames will be ignored (skipped) by decompressor. 2346 The format of skippable frames is as follows : 2347 a) Skippable frame ID - 4 Bytes, Little endian format, any value from 0x184D2A50 to 0x184D2A5F 2348 b) Frame Size - 4 Bytes, Little endian format, unsigned 32-bits 2349 c) Frame Content - any content (User Data) of length equal to Frame Size 2350 For skippable frames ZSTD_getFrameHeader() returns zfhPtr->frameType==ZSTD_skippableFrame. 2351 For skippable frames ZSTD_decompressContinue() always returns 0 : it only skips the content. 2352 */ 2353 2354 /*===== Buffer-less streaming decompression functions =====*/ 2355 typedef enum { ZSTD_frame, ZSTD_skippableFrame } ZSTD_frameType_e; 2356 typedef struct { 2357 unsigned long long frameContentSize; /* if == ZSTD_CONTENTSIZE_UNKNOWN, it means this field is not available. 0 means "empty" */ 2358 unsigned long long windowSize; /* can be very large, up to <= frameContentSize */ 2359 unsigned blockSizeMax; 2360 ZSTD_frameType_e frameType; /* if == ZSTD_skippableFrame, frameContentSize is the size of skippable content */ 2361 unsigned headerSize; 2362 unsigned dictID; 2363 unsigned checksumFlag; 2364 } ZSTD_frameHeader; 2365 2366 /*! ZSTD_getFrameHeader() : 2367 * decode Frame Header, or requires larger `srcSize`. 2368 * @return : 0, `zfhPtr` is correctly filled, 2369 * >0, `srcSize` is too small, value is wanted `srcSize` amount, 2370 * or an error code, which can be tested using ZSTD_isError() */ 2371 ZSTDLIB_API size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); /*< doesn't consume input */ 2372 /*! ZSTD_getFrameHeader_advanced() : 2373 * same as ZSTD_getFrameHeader(), 2374 * with added capability to select a format (like ZSTD_f_zstd1_magicless) */ 2375 ZSTDLIB_API size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format); 2376 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 */ 2377 2378 ZSTDLIB_API size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx); 2379 ZSTDLIB_API size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); 2380 ZSTDLIB_API size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); 2381 2382 ZSTDLIB_API size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx); 2383 ZSTDLIB_API size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 2384 2385 /* misc */ 2386 ZSTDLIB_API void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx); 2387 typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e; 2388 ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx); 2389 2390 2391 2392 2393 /* ============================ */ 2394 /* Block level API */ 2395 /* ============================ */ 2396 2397 /*! 2398 Block functions produce and decode raw zstd blocks, without frame metadata. 2399 Frame metadata cost is typically ~12 bytes, which can be non-negligible for very small blocks (< 100 bytes). 2400 But users will have to take in charge needed metadata to regenerate data, such as compressed and content sizes. 2401 2402 A few rules to respect : 2403 - Compressing and decompressing require a context structure 2404 + Use ZSTD_createCCtx() and ZSTD_createDCtx() 2405 - It is necessary to init context before starting 2406 + compression : any ZSTD_compressBegin*() variant, including with dictionary 2407 + decompression : any ZSTD_decompressBegin*() variant, including with dictionary 2408 + copyCCtx() and copyDCtx() can be used too 2409 - Block size is limited, it must be <= ZSTD_getBlockSize() <= ZSTD_BLOCKSIZE_MAX == 128 KB 2410 + If input is larger than a block size, it's necessary to split input data into multiple blocks 2411 + For inputs larger than a single block, consider using regular ZSTD_compress() instead. 2412 Frame metadata is not that costly, and quickly becomes negligible as source size grows larger than a block. 2413 - When a block is considered not compressible enough, ZSTD_compressBlock() result will be 0 (zero) ! 2414 ===> In which case, nothing is produced into `dst` ! 2415 + User __must__ test for such outcome and deal directly with uncompressed data 2416 + A block cannot be declared incompressible if ZSTD_compressBlock() return value was != 0. 2417 Doing so would mess up with statistics history, leading to potential data corruption. 2418 + ZSTD_decompressBlock() _doesn't accept uncompressed data as input_ !! 2419 + In case of multiple successive blocks, should some of them be uncompressed, 2420 decoder must be informed of their existence in order to follow proper history. 2421 Use ZSTD_insertBlock() for such a case. 2422 */ 2423 2424 /*===== Raw zstd block functions =====*/ 2425 ZSTDLIB_API size_t ZSTD_getBlockSize (const ZSTD_CCtx* cctx); 2426 ZSTDLIB_API size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 2427 ZSTDLIB_API size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); 2428 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. */ 2429 2430 2431 #endif /* ZSTD_H_ZSTD_STATIC_LINKING_ONLY */ 2432 2433