1 /* 2 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 11 #ifndef DICTBUILDER_H_001 12 #define DICTBUILDER_H_001 13 14 #if defined (__cplusplus) 15 extern "C" { 16 #endif 17 18 19 /*====== Dependencies ======*/ 20 #include <stddef.h> /* size_t */ 21 22 23 /* ===== ZDICTLIB_API : control library symbols visibility ===== */ 24 #ifndef ZDICTLIB_VISIBILITY 25 # if defined(__GNUC__) && (__GNUC__ >= 4) 26 # define ZDICTLIB_VISIBILITY __attribute__ ((visibility ("default"))) 27 # else 28 # define ZDICTLIB_VISIBILITY 29 # endif 30 #endif 31 #if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) 32 # define ZDICTLIB_API __declspec(dllexport) ZDICTLIB_VISIBILITY 33 #elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) 34 # define ZDICTLIB_API __declspec(dllimport) ZDICTLIB_VISIBILITY /* It isn't required but allows to generate better code, saving a function pointer load from the IAT and an indirect jump.*/ 35 #else 36 # define ZDICTLIB_API ZDICTLIB_VISIBILITY 37 #endif 38 39 40 /*! ZDICT_trainFromBuffer(): 41 * Train a dictionary from an array of samples. 42 * Redirect towards ZDICT_optimizeTrainFromBuffer_fastCover() single-threaded, with d=8, steps=4, 43 * f=20, and accel=1. 44 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, 45 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. 46 * The resulting dictionary will be saved into `dictBuffer`. 47 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 48 * or an error code, which can be tested with ZDICT_isError(). 49 * Note: Dictionary training will fail if there are not enough samples to construct a 50 * dictionary, or if most of the samples are too small (< 8 bytes being the lower limit). 51 * If dictionary training fails, you should use zstd without a dictionary, as the dictionary 52 * would've been ineffective anyways. If you believe your samples would benefit from a dictionary 53 * please open an issue with details, and we can look into it. 54 * Note: ZDICT_trainFromBuffer()'s memory usage is about 6 MB. 55 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. 56 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. 57 * In general, it's recommended to provide a few thousands samples, though this can vary a lot. 58 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. 59 */ 60 ZDICTLIB_API size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity, 61 const void* samplesBuffer, 62 const size_t* samplesSizes, unsigned nbSamples); 63 64 65 /*====== Helper functions ======*/ 66 ZDICTLIB_API unsigned ZDICT_getDictID(const void* dictBuffer, size_t dictSize); /**< extracts dictID; @return zero if error (not a valid dictionary) */ 67 ZDICTLIB_API unsigned ZDICT_isError(size_t errorCode); 68 ZDICTLIB_API const char* ZDICT_getErrorName(size_t errorCode); 69 70 71 72 #ifdef ZDICT_STATIC_LINKING_ONLY 73 74 /* ==================================================================================== 75 * The definitions in this section are considered experimental. 76 * They should never be used with a dynamic library, as they may change in the future. 77 * They are provided for advanced usages. 78 * Use them only in association with static linking. 79 * ==================================================================================== */ 80 81 typedef struct { 82 int compressionLevel; /* optimize for a specific zstd compression level; 0 means default */ 83 unsigned notificationLevel; /* Write log to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */ 84 unsigned dictID; /* force dictID value; 0 means auto mode (32-bits random value) */ 85 } ZDICT_params_t; 86 87 /*! ZDICT_cover_params_t: 88 * k and d are the only required parameters. 89 * For others, value 0 means default. 90 */ 91 typedef struct { 92 unsigned k; /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */ 93 unsigned d; /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */ 94 unsigned steps; /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */ 95 unsigned nbThreads; /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */ 96 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 */ 97 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 */ 98 unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */ 99 ZDICT_params_t zParams; 100 } ZDICT_cover_params_t; 101 102 typedef struct { 103 unsigned k; /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */ 104 unsigned d; /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */ 105 unsigned f; /* log of size of frequency array : constraint: 0 < f <= 31 : 1 means default(20)*/ 106 unsigned steps; /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */ 107 unsigned nbThreads; /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */ 108 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 */ 109 unsigned accel; /* Acceleration level: constraint: 0 < accel <= 10, higher means faster and less accurate, 0 means default(1) */ 110 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 */ 111 unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */ 112 113 ZDICT_params_t zParams; 114 } ZDICT_fastCover_params_t; 115 116 /*! ZDICT_trainFromBuffer_cover(): 117 * Train a dictionary from an array of samples using the COVER algorithm. 118 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, 119 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. 120 * The resulting dictionary will be saved into `dictBuffer`. 121 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 122 * or an error code, which can be tested with ZDICT_isError(). 123 * See ZDICT_trainFromBuffer() for details on failure modes. 124 * Note: ZDICT_trainFromBuffer_cover() requires about 9 bytes of memory for each input byte. 125 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. 126 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. 127 * In general, it's recommended to provide a few thousands samples, though this can vary a lot. 128 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. 129 */ 130 ZDICTLIB_API size_t ZDICT_trainFromBuffer_cover( 131 void *dictBuffer, size_t dictBufferCapacity, 132 const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples, 133 ZDICT_cover_params_t parameters); 134 135 /*! ZDICT_optimizeTrainFromBuffer_cover(): 136 * The same requirements as above hold for all the parameters except `parameters`. 137 * This function tries many parameter combinations and picks the best parameters. 138 * `*parameters` is filled with the best parameters found, 139 * dictionary constructed with those parameters is stored in `dictBuffer`. 140 * 141 * All of the parameters d, k, steps are optional. 142 * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}. 143 * if steps is zero it defaults to its default value. 144 * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000]. 145 * 146 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 147 * or an error code, which can be tested with ZDICT_isError(). 148 * On success `*parameters` contains the parameters selected. 149 * See ZDICT_trainFromBuffer() for details on failure modes. 150 * 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. 151 */ 152 ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_cover( 153 void* dictBuffer, size_t dictBufferCapacity, 154 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples, 155 ZDICT_cover_params_t* parameters); 156 157 /*! ZDICT_trainFromBuffer_fastCover(): 158 * Train a dictionary from an array of samples using a modified version of COVER algorithm. 159 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, 160 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. 161 * d and k are required. 162 * All other parameters are optional, will use default values if not provided 163 * The resulting dictionary will be saved into `dictBuffer`. 164 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 165 * or an error code, which can be tested with ZDICT_isError(). 166 * See ZDICT_trainFromBuffer() for details on failure modes. 167 * Note: ZDICT_trainFromBuffer_fastCover() requires 6 * 2^f bytes of memory. 168 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. 169 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. 170 * In general, it's recommended to provide a few thousands samples, though this can vary a lot. 171 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. 172 */ 173 ZDICTLIB_API size_t ZDICT_trainFromBuffer_fastCover(void *dictBuffer, 174 size_t dictBufferCapacity, const void *samplesBuffer, 175 const size_t *samplesSizes, unsigned nbSamples, 176 ZDICT_fastCover_params_t parameters); 177 178 /*! ZDICT_optimizeTrainFromBuffer_fastCover(): 179 * The same requirements as above hold for all the parameters except `parameters`. 180 * This function tries many parameter combinations (specifically, k and d combinations) 181 * and picks the best parameters. `*parameters` is filled with the best parameters found, 182 * dictionary constructed with those parameters is stored in `dictBuffer`. 183 * All of the parameters d, k, steps, f, and accel are optional. 184 * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}. 185 * if steps is zero it defaults to its default value. 186 * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000]. 187 * If f is zero, default value of 20 is used. 188 * If accel is zero, default value of 1 is used. 189 * 190 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 191 * or an error code, which can be tested with ZDICT_isError(). 192 * On success `*parameters` contains the parameters selected. 193 * See ZDICT_trainFromBuffer() for details on failure modes. 194 * Note: ZDICT_optimizeTrainFromBuffer_fastCover() requires about 6 * 2^f bytes of memory for each thread. 195 */ 196 ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_fastCover(void* dictBuffer, 197 size_t dictBufferCapacity, const void* samplesBuffer, 198 const size_t* samplesSizes, unsigned nbSamples, 199 ZDICT_fastCover_params_t* parameters); 200 201 /*! ZDICT_finalizeDictionary(): 202 * Given a custom content as a basis for dictionary, and a set of samples, 203 * finalize dictionary by adding headers and statistics. 204 * 205 * Samples must be stored concatenated in a flat buffer `samplesBuffer`, 206 * supplied with an array of sizes `samplesSizes`, providing the size of each sample in order. 207 * 208 * dictContentSize must be >= ZDICT_CONTENTSIZE_MIN bytes. 209 * maxDictSize must be >= dictContentSize, and must be >= ZDICT_DICTSIZE_MIN bytes. 210 * 211 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`), 212 * or an error code, which can be tested by ZDICT_isError(). 213 * Note: ZDICT_finalizeDictionary() will push notifications into stderr if instructed to, using notificationLevel>0. 214 * Note 2: dictBuffer and dictContent can overlap 215 */ 216 #define ZDICT_CONTENTSIZE_MIN 128 217 #define ZDICT_DICTSIZE_MIN 256 218 ZDICTLIB_API size_t ZDICT_finalizeDictionary(void* dictBuffer, size_t dictBufferCapacity, 219 const void* dictContent, size_t dictContentSize, 220 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples, 221 ZDICT_params_t parameters); 222 223 typedef struct { 224 unsigned selectivityLevel; /* 0 means default; larger => select more => larger dictionary */ 225 ZDICT_params_t zParams; 226 } ZDICT_legacy_params_t; 227 228 /*! ZDICT_trainFromBuffer_legacy(): 229 * Train a dictionary from an array of samples. 230 * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, 231 * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. 232 * The resulting dictionary will be saved into `dictBuffer`. 233 * `parameters` is optional and can be provided with values set to 0 to mean "default". 234 * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) 235 * or an error code, which can be tested with ZDICT_isError(). 236 * See ZDICT_trainFromBuffer() for details on failure modes. 237 * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. 238 * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. 239 * In general, it's recommended to provide a few thousands samples, though this can vary a lot. 240 * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. 241 * Note: ZDICT_trainFromBuffer_legacy() will send notifications into stderr if instructed to, using notificationLevel>0. 242 */ 243 ZDICTLIB_API size_t ZDICT_trainFromBuffer_legacy( 244 void *dictBuffer, size_t dictBufferCapacity, 245 const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples, 246 ZDICT_legacy_params_t parameters); 247 248 /* Deprecation warnings */ 249 /* It is generally possible to disable deprecation warnings from compiler, 250 for example with -Wno-deprecated-declarations for gcc 251 or _CRT_SECURE_NO_WARNINGS in Visual. 252 Otherwise, it's also possible to manually define ZDICT_DISABLE_DEPRECATE_WARNINGS */ 253 #ifdef ZDICT_DISABLE_DEPRECATE_WARNINGS 254 # define ZDICT_DEPRECATED(message) ZDICTLIB_API /* disable deprecation warnings */ 255 #else 256 # define ZDICT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) 257 # if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */ 258 # define ZDICT_DEPRECATED(message) [[deprecated(message)]] ZDICTLIB_API 259 # elif (ZDICT_GCC_VERSION >= 405) || defined(__clang__) 260 # define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated(message))) 261 # elif (ZDICT_GCC_VERSION >= 301) 262 # define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated)) 263 # elif defined(_MSC_VER) 264 # define ZDICT_DEPRECATED(message) ZDICTLIB_API __declspec(deprecated(message)) 265 # else 266 # pragma message("WARNING: You need to implement ZDICT_DEPRECATED for this compiler") 267 # define ZDICT_DEPRECATED(message) ZDICTLIB_API 268 # endif 269 #endif /* ZDICT_DISABLE_DEPRECATE_WARNINGS */ 270 271 ZDICT_DEPRECATED("use ZDICT_finalizeDictionary() instead") 272 size_t ZDICT_addEntropyTablesFromBuffer(void* dictBuffer, size_t dictContentSize, size_t dictBufferCapacity, 273 const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples); 274 275 276 #endif /* ZDICT_STATIC_LINKING_ONLY */ 277 278 #if defined (__cplusplus) 279 } 280 #endif 281 282 #endif /* DICTBUILDER_H_001 */ 283