1 /* 2 * Copyright (c) Meta Platforms, Inc. and affiliates. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 11 #if defined (__cplusplus) 12 extern "C" { 13 #endif 14 15 #ifndef ZSTD_ZDICT_H 16 #define ZSTD_ZDICT_H 17 18 /*====== Dependencies ======*/ 19 #include <stddef.h> /* size_t */ 20 21 22 /* ===== ZDICTLIB_API : control library symbols visibility ===== */ 23 #ifndef ZDICTLIB_VISIBLE 24 /* Backwards compatibility with old macro name */ 25 # ifdef ZDICTLIB_VISIBILITY 26 # define ZDICTLIB_VISIBLE ZDICTLIB_VISIBILITY 27 # elif defined(__GNUC__) && (__GNUC__ >= 4) && !defined(__MINGW32__) 28 # define ZDICTLIB_VISIBLE __attribute__ ((visibility ("default"))) 29 # else 30 # define ZDICTLIB_VISIBLE 31 # endif 32 #endif 33 34 #ifndef ZDICTLIB_HIDDEN 35 # if defined(__GNUC__) && (__GNUC__ >= 4) && !defined(__MINGW32__) 36 # define ZDICTLIB_HIDDEN __attribute__ ((visibility ("hidden"))) 37 # else 38 # define ZDICTLIB_HIDDEN 39 # endif 40 #endif 41 42 #if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) 43 # define ZDICTLIB_API __declspec(dllexport) ZDICTLIB_VISIBLE 44 #elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) 45 # define ZDICTLIB_API __declspec(dllimport) ZDICTLIB_VISIBLE /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/ 46 #else 47 # define ZDICTLIB_API ZDICTLIB_VISIBLE 48 #endif 49 50 /******************************************************************************* 51 * Zstd dictionary builder 52 * 53 * FAQ 54 * === 55 * Why should I use a dictionary? 56 * ------------------------------ 57 * 58 * Zstd can use dictionaries to improve compression ratio of small data. 59 * Traditionally small files don't compress well because there is very little 60 * repetition in a single sample, since it is small. But, if you are compressing 61 * many similar files, like a bunch of JSON records that share the same 62 * structure, you can train a dictionary on ahead of time on some samples of 63 * these files. Then, zstd can use the dictionary to find repetitions that are 64 * present across samples. This can vastly improve compression ratio. 65 * 66 * When is a dictionary useful? 67 * ---------------------------- 68 * 69 * Dictionaries are useful when compressing many small files that are similar. 70 * The larger a file is, the less benefit a dictionary will have. Generally, 71 * we don't expect dictionary compression to be effective past 100KB. And the 72 * smaller a file is, the more we would expect the dictionary to help. 73 * 74 * How do I use a dictionary? 75 * -------------------------- 76 * 77 * Simply pass the dictionary to the zstd compressor with 78 * `ZSTD_CCtx_loadDictionary()`. The same dictionary must then be passed to 79 * the decompressor, using `ZSTD_DCtx_loadDictionary()`. There are other 80 * more advanced functions that allow selecting some options, see zstd.h for 81 * complete documentation. 82 * 83 * What is a zstd dictionary? 84 * -------------------------- 85 * 86 * A zstd dictionary has two pieces: Its header, and its content. The header 87 * contains a magic number, the dictionary ID, and entropy tables. These 88 * entropy tables allow zstd to save on header costs in the compressed file, 89 * which really matters for small data. The content is just bytes, which are 90 * repeated content that is common across many samples. 91 * 92 * What is a raw content dictionary? 93 * --------------------------------- 94 * 95 * A raw content dictionary is just bytes. It doesn't have a zstd dictionary 96 * header, a dictionary ID, or entropy tables. Any buffer is a valid raw 97 * content dictionary. 98 * 99 * How do I train a dictionary? 100 * ---------------------------- 101 * 102 * Gather samples from your use case. These samples should be similar to each 103 * other. If you have several use cases, you could try to train one dictionary 104 * per use case. 105 * 106 * Pass those samples to `ZDICT_trainFromBuffer()` and that will train your 107 * dictionary. There are a few advanced versions of this function, but this 108 * is a great starting point. If you want to further tune your dictionary 109 * you could try `ZDICT_optimizeTrainFromBuffer_cover()`. If that is too slow 110 * you can try `ZDICT_optimizeTrainFromBuffer_fastCover()`. 111 * 112 * If the dictionary training function fails, that is likely because you 113 * either passed too few samples, or a dictionary would not be effective 114 * for your data. Look at the messages that the dictionary trainer printed, 115 * if it doesn't say too few samples, then a dictionary would not be effective. 116 * 117 * How large should my dictionary be? 118 * ---------------------------------- 119 * 120 * A reasonable dictionary size, the `dictBufferCapacity`, is about 100KB. 121 * The zstd CLI defaults to a 110KB dictionary. You likely don't need a 122 * dictionary larger than that. But, most use cases can get away with a 123 * smaller dictionary. The advanced dictionary builders can automatically 124 * shrink the dictionary for you, and select the smallest size that doesn't 125 * hurt compression ratio too much. See the `shrinkDict` parameter. 126 * A smaller dictionary can save memory, and potentially speed up 127 * compression. 128 * 129 * How many samples should I provide to the dictionary builder? 130 * ------------------------------------------------------------ 131 * 132 * We generally recommend passing ~100x the size of the dictionary 133 * in samples. A few thousand should suffice. Having too few samples 134 * can hurt the dictionaries effectiveness. Having more samples will 135 * only improve the dictionaries effectiveness. But having too many 136 * samples can slow down the dictionary builder. 137 * 138 * How do I determine if a dictionary will be effective? 139 * ----------------------------------------------------- 140 * 141 * Simply train a dictionary and try it out. You can use zstd's built in 142 * benchmarking tool to test the dictionary effectiveness. 143 * 144 * # Benchmark levels 1-3 without a dictionary 145 * zstd -b1e3 -r /path/to/my/files 146 * # Benchmark levels 1-3 with a dictionary 147 * zstd -b1e3 -r /path/to/my/files -D /path/to/my/dictionary 148 * 149 * When should I retrain a dictionary? 150 * ----------------------------------- 151 * 152 * You should retrain a dictionary when its effectiveness drops. Dictionary 153 * effectiveness drops as the data you are compressing changes. Generally, we do 154 * expect dictionaries to "decay" over time, as your data changes, but the rate 155 * at which they decay depends on your use case. Internally, we regularly 156 * retrain dictionaries, and if the new dictionary performs significantly 157 * better than the old dictionary, we will ship the new dictionary. 158 * 159 * I have a raw content dictionary, how do I turn it into a zstd dictionary? 160 * ------------------------------------------------------------------------- 161 * 162 * If you have a raw content dictionary, e.g. by manually constructing it, or 163 * using a third-party dictionary builder, you can turn it into a zstd 164 * dictionary by using `ZDICT_finalizeDictionary()`. You'll also have to 165 * provide some samples of the data. It will add the zstd header to the 166 * raw content, which contains a dictionary ID and entropy tables, which 167 * will improve compression ratio, and allow zstd to write the dictionary ID 168 * into the frame, if you so choose. 169 * 170 * Do I have to use zstd's dictionary builder? 171 * ------------------------------------------- 172 * 173 * No! You can construct dictionary content however you please, it is just 174 * bytes. It will always be valid as a raw content dictionary. If you want 175 * a zstd dictionary, which can improve compression ratio, use 176 * `ZDICT_finalizeDictionary()`. 177 * 178 * What is the attack surface of a zstd dictionary? 179 * ------------------------------------------------ 180 * 181 * Zstd is heavily fuzz tested, including loading fuzzed dictionaries, so 182 * zstd should never crash, or access out-of-bounds memory no matter what 183 * the dictionary is. However, if an attacker can control the dictionary 184 * during decompression, they can cause zstd to generate arbitrary bytes, 185 * just like if they controlled the compressed data. 186 * 187 ******************************************************************************/ 188 189 190 /*! ZDICT_trainFromBuffer(): 191 * Train a dictionary from an array of samples. 192 * Redirect towards ZDICT_optimizeTrainFromBuffer_fastCover() single-threaded, with d=8, steps=4, 193 * f=20, and accel=1. 194 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, 195 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. 196 * The resulting dictionary will be saved into `dictBuffer`. 197 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 198 * or an error code, which can be tested with ZDICT_isError(). 199 * Note: Dictionary training will fail if there are not enough samples to construct a 200 * dictionary, or if most of the samples are too small (< 8 bytes being the lower limit). 201 * If dictionary training fails, you should use zstd without a dictionary, as the dictionary 202 * would've been ineffective anyways. If you believe your samples would benefit from a dictionary 203 * please open an issue with details, and we can look into it. 204 * Note: ZDICT_trainFromBuffer()'s memory usage is about 6 MB. 205 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. 206 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. 207 * In general, it's recommended to provide a few thousands samples, though this can vary a lot. 208 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. 209 */ 210 ZDICTLIB_API size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity, 211 const void* samplesBuffer, 212 const size_t* samplesSizes, unsigned nbSamples); 213 214 typedef struct { 215 int compressionLevel; /**< optimize for a specific zstd compression level; 0 means default */ 216 unsigned notificationLevel; /**< Write log to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */ 217 unsigned dictID; /**< force dictID value; 0 means auto mode (32-bits random value) 218 * NOTE: The zstd format reserves some dictionary IDs for future use. 219 * You may use them in private settings, but be warned that they 220 * may be used by zstd in a public dictionary registry in the future. 221 * These dictionary IDs are: 222 * - low range : <= 32767 223 * - high range : >= (2^31) 224 */ 225 } ZDICT_params_t; 226 227 /*! ZDICT_finalizeDictionary(): 228 * Given a custom content as a basis for dictionary, and a set of samples, 229 * finalize dictionary by adding headers and statistics according to the zstd 230 * dictionary format. 231 * 232 * Samples must be stored concatenated in a flat buffer `samplesBuffer`, 233 * supplied with an array of sizes `samplesSizes`, providing the size of each 234 * sample in order. The samples are used to construct the statistics, so they 235 * should be representative of what you will compress with this dictionary. 236 * 237 * The compression level can be set in `parameters`. You should pass the 238 * compression level you expect to use in production. The statistics for each 239 * compression level differ, so tuning the dictionary for the compression level 240 * can help quite a bit. 241 * 242 * You can set an explicit dictionary ID in `parameters`, or allow us to pick 243 * a random dictionary ID for you, but we can't guarantee no collisions. 244 * 245 * The dstDictBuffer and the dictContent may overlap, and the content will be 246 * appended to the end of the header. If the header + the content doesn't fit in 247 * maxDictSize the beginning of the content is truncated to make room, since it 248 * is presumed that the most profitable content is at the end of the dictionary, 249 * since that is the cheapest to reference. 250 * 251 * `maxDictSize` must be >= max(dictContentSize, ZSTD_DICTSIZE_MIN). 252 * 253 * @return: size of dictionary stored into `dstDictBuffer` (<= `maxDictSize`), 254 * or an error code, which can be tested by ZDICT_isError(). 255 * Note: ZDICT_finalizeDictionary() will push notifications into stderr if 256 * instructed to, using notificationLevel>0. 257 * NOTE: This function currently may fail in several edge cases including: 258 * * Not enough samples 259 * * Samples are uncompressible 260 * * Samples are all exactly the same 261 */ 262 ZDICTLIB_API size_t ZDICT_finalizeDictionary(void* dstDictBuffer, size_t maxDictSize, 263 const void* dictContent, size_t dictContentSize, 264 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples, 265 ZDICT_params_t parameters); 266 267 268 /*====== Helper functions ======*/ 269 ZDICTLIB_API unsigned ZDICT_getDictID(const void* dictBuffer, size_t dictSize); /**< extracts dictID; @return zero if error (not a valid dictionary) */ 270 ZDICTLIB_API size_t ZDICT_getDictHeaderSize(const void* dictBuffer, size_t dictSize); /* returns dict header size; returns a ZSTD error code on failure */ 271 ZDICTLIB_API unsigned ZDICT_isError(size_t errorCode); 272 ZDICTLIB_API const char* ZDICT_getErrorName(size_t errorCode); 273 274 #endif /* ZSTD_ZDICT_H */ 275 276 #if defined(ZDICT_STATIC_LINKING_ONLY) && !defined(ZSTD_ZDICT_H_STATIC) 277 #define ZSTD_ZDICT_H_STATIC 278 279 /* This can be overridden externally to hide static symbols. */ 280 #ifndef ZDICTLIB_STATIC_API 281 # if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) 282 # define ZDICTLIB_STATIC_API __declspec(dllexport) ZDICTLIB_VISIBLE 283 # elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) 284 # define ZDICTLIB_STATIC_API __declspec(dllimport) ZDICTLIB_VISIBLE 285 # else 286 # define ZDICTLIB_STATIC_API ZDICTLIB_VISIBLE 287 # endif 288 #endif 289 290 /* ==================================================================================== 291 * The definitions in this section are considered experimental. 292 * They should never be used with a dynamic library, as they may change in the future. 293 * They are provided for advanced usages. 294 * Use them only in association with static linking. 295 * ==================================================================================== */ 296 297 #define ZDICT_DICTSIZE_MIN 256 298 /* Deprecated: Remove in v1.6.0 */ 299 #define ZDICT_CONTENTSIZE_MIN 128 300 301 /*! ZDICT_cover_params_t: 302 * k and d are the only required parameters. 303 * For others, value 0 means default. 304 */ 305 typedef struct { 306 unsigned k; /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */ 307 unsigned d; /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */ 308 unsigned steps; /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */ 309 unsigned nbThreads; /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */ 310 double splitPoint; /* Percentage of samples used for training: Only used for optimization : the first nbSamples * splitPoint samples will be used to training, the last nbSamples * (1 - splitPoint) samples will be used for testing, 0 means default (1.0), 1.0 when all samples are used for both training and testing */ 311 unsigned shrinkDict; /* Train dictionaries to shrink in size starting from the minimum size and selects the smallest dictionary that is shrinkDictMaxRegression% worse than the largest dictionary. 0 means no shrinking and 1 means shrinking */ 312 unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */ 313 ZDICT_params_t zParams; 314 } ZDICT_cover_params_t; 315 316 typedef struct { 317 unsigned k; /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */ 318 unsigned d; /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */ 319 unsigned f; /* log of size of frequency array : constraint: 0 < f <= 31 : 1 means default(20)*/ 320 unsigned steps; /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */ 321 unsigned nbThreads; /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */ 322 double splitPoint; /* Percentage of samples used for training: Only used for optimization : the first nbSamples * splitPoint samples will be used to training, the last nbSamples * (1 - splitPoint) samples will be used for testing, 0 means default (0.75), 1.0 when all samples are used for both training and testing */ 323 unsigned accel; /* Acceleration level: constraint: 0 < accel <= 10, higher means faster and less accurate, 0 means default(1) */ 324 unsigned shrinkDict; /* Train dictionaries to shrink in size starting from the minimum size and selects the smallest dictionary that is shrinkDictMaxRegression% worse than the largest dictionary. 0 means no shrinking and 1 means shrinking */ 325 unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */ 326 327 ZDICT_params_t zParams; 328 } ZDICT_fastCover_params_t; 329 330 /*! ZDICT_trainFromBuffer_cover(): 331 * Train a dictionary from an array of samples using the COVER algorithm. 332 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, 333 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. 334 * The resulting dictionary will be saved into `dictBuffer`. 335 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 336 * or an error code, which can be tested with ZDICT_isError(). 337 * See ZDICT_trainFromBuffer() for details on failure modes. 338 * Note: ZDICT_trainFromBuffer_cover() requires about 9 bytes of memory for each input byte. 339 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. 340 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. 341 * In general, it's recommended to provide a few thousands samples, though this can vary a lot. 342 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. 343 */ 344 ZDICTLIB_STATIC_API size_t ZDICT_trainFromBuffer_cover( 345 void *dictBuffer, size_t dictBufferCapacity, 346 const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples, 347 ZDICT_cover_params_t parameters); 348 349 /*! ZDICT_optimizeTrainFromBuffer_cover(): 350 * The same requirements as above hold for all the parameters except `parameters`. 351 * This function tries many parameter combinations and picks the best parameters. 352 * `*parameters` is filled with the best parameters found, 353 * dictionary constructed with those parameters is stored in `dictBuffer`. 354 * 355 * All of the parameters d, k, steps are optional. 356 * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}. 357 * if steps is zero it defaults to its default value. 358 * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000]. 359 * 360 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 361 * or an error code, which can be tested with ZDICT_isError(). 362 * On success `*parameters` contains the parameters selected. 363 * See ZDICT_trainFromBuffer() for details on failure modes. 364 * Note: ZDICT_optimizeTrainFromBuffer_cover() requires about 8 bytes of memory for each input byte and additionally another 5 bytes of memory for each byte of memory for each thread. 365 */ 366 ZDICTLIB_STATIC_API size_t ZDICT_optimizeTrainFromBuffer_cover( 367 void* dictBuffer, size_t dictBufferCapacity, 368 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples, 369 ZDICT_cover_params_t* parameters); 370 371 /*! ZDICT_trainFromBuffer_fastCover(): 372 * Train a dictionary from an array of samples using a modified version of COVER algorithm. 373 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, 374 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. 375 * d and k are required. 376 * All other parameters are optional, will use default values if not provided 377 * The resulting dictionary will be saved into `dictBuffer`. 378 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 379 * or an error code, which can be tested with ZDICT_isError(). 380 * See ZDICT_trainFromBuffer() for details on failure modes. 381 * Note: ZDICT_trainFromBuffer_fastCover() requires 6 * 2^f bytes of memory. 382 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. 383 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. 384 * In general, it's recommended to provide a few thousands samples, though this can vary a lot. 385 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. 386 */ 387 ZDICTLIB_STATIC_API size_t ZDICT_trainFromBuffer_fastCover(void *dictBuffer, 388 size_t dictBufferCapacity, const void *samplesBuffer, 389 const size_t *samplesSizes, unsigned nbSamples, 390 ZDICT_fastCover_params_t parameters); 391 392 /*! ZDICT_optimizeTrainFromBuffer_fastCover(): 393 * The same requirements as above hold for all the parameters except `parameters`. 394 * This function tries many parameter combinations (specifically, k and d combinations) 395 * and picks the best parameters. `*parameters` is filled with the best parameters found, 396 * dictionary constructed with those parameters is stored in `dictBuffer`. 397 * All of the parameters d, k, steps, f, and accel are optional. 398 * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}. 399 * if steps is zero it defaults to its default value. 400 * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000]. 401 * If f is zero, default value of 20 is used. 402 * If accel is zero, default value of 1 is used. 403 * 404 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 405 * or an error code, which can be tested with ZDICT_isError(). 406 * On success `*parameters` contains the parameters selected. 407 * See ZDICT_trainFromBuffer() for details on failure modes. 408 * Note: ZDICT_optimizeTrainFromBuffer_fastCover() requires about 6 * 2^f bytes of memory for each thread. 409 */ 410 ZDICTLIB_STATIC_API size_t ZDICT_optimizeTrainFromBuffer_fastCover(void* dictBuffer, 411 size_t dictBufferCapacity, const void* samplesBuffer, 412 const size_t* samplesSizes, unsigned nbSamples, 413 ZDICT_fastCover_params_t* parameters); 414 415 typedef struct { 416 unsigned selectivityLevel; /* 0 means default; larger => select more => larger dictionary */ 417 ZDICT_params_t zParams; 418 } ZDICT_legacy_params_t; 419 420 /*! ZDICT_trainFromBuffer_legacy(): 421 * Train a dictionary from an array of samples. 422 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, 423 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. 424 * The resulting dictionary will be saved into `dictBuffer`. 425 * `parameters` is optional and can be provided with values set to 0 to mean "default". 426 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 427 * or an error code, which can be tested with ZDICT_isError(). 428 * See ZDICT_trainFromBuffer() for details on failure modes. 429 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. 430 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. 431 * In general, it's recommended to provide a few thousands samples, though this can vary a lot. 432 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. 433 * Note: ZDICT_trainFromBuffer_legacy() will send notifications into stderr if instructed to, using notificationLevel>0. 434 */ 435 ZDICTLIB_STATIC_API size_t ZDICT_trainFromBuffer_legacy( 436 void* dictBuffer, size_t dictBufferCapacity, 437 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples, 438 ZDICT_legacy_params_t parameters); 439 440 441 /* Deprecation warnings */ 442 /* It is generally possible to disable deprecation warnings from compiler, 443 for example with -Wno-deprecated-declarations for gcc 444 or _CRT_SECURE_NO_WARNINGS in Visual. 445 Otherwise, it's also possible to manually define ZDICT_DISABLE_DEPRECATE_WARNINGS */ 446 #ifdef ZDICT_DISABLE_DEPRECATE_WARNINGS 447 # define ZDICT_DEPRECATED(message) /* disable deprecation warnings */ 448 #else 449 # define ZDICT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) 450 # if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */ 451 # define ZDICT_DEPRECATED(message) [[deprecated(message)]] 452 # elif defined(__clang__) || (ZDICT_GCC_VERSION >= 405) 453 # define ZDICT_DEPRECATED(message) __attribute__((deprecated(message))) 454 # elif (ZDICT_GCC_VERSION >= 301) 455 # define ZDICT_DEPRECATED(message) __attribute__((deprecated)) 456 # elif defined(_MSC_VER) 457 # define ZDICT_DEPRECATED(message) __declspec(deprecated(message)) 458 # else 459 # pragma message("WARNING: You need to implement ZDICT_DEPRECATED for this compiler") 460 # define ZDICT_DEPRECATED(message) 461 # endif 462 #endif /* ZDICT_DISABLE_DEPRECATE_WARNINGS */ 463 464 ZDICT_DEPRECATED("use ZDICT_finalizeDictionary() instead") 465 ZDICTLIB_STATIC_API 466 size_t ZDICT_addEntropyTablesFromBuffer(void* dictBuffer, size_t dictContentSize, size_t dictBufferCapacity, 467 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples); 468 469 470 #endif /* ZSTD_ZDICT_H_STATIC */ 471 472 #if defined (__cplusplus) 473 } 474 #endif 475