Editando: zdict.h
/* * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. * All rights reserved. * * This source code is licensed under both the BSD-style license (found in the * LICENSE file in the root directory of this source tree) and the GPLv2 (found * in the COPYING file in the root directory of this source tree). * You may select, at your option, one of the above-listed licenses. */ #ifndef DICTBUILDER_H_001 #define DICTBUILDER_H_001 #if defined (__cplusplus) extern "C" { #endif /*====== Dependencies ======*/ #include <stddef.h> /* size_t */ /* ===== ZDICTLIB_API : control library symbols visibility ===== */ #ifndef ZDICTLIB_VISIBILITY # if defined(__GNUC__) && (__GNUC__ >= 4) # define ZDICTLIB_VISIBILITY __attribute__ ((visibility ("default"))) # else # define ZDICTLIB_VISIBILITY # endif #endif #if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1) # define ZDICTLIB_API __declspec(dllexport) ZDICTLIB_VISIBILITY #elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1) # 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.*/ #else # define ZDICTLIB_API ZDICTLIB_VISIBILITY #endif /*! ZDICT_trainFromBuffer(): * Train a dictionary from an array of samples. * Redirect towards ZDICT_optimizeTrainFromBuffer_fastCover() single-threaded, with d=8, steps=4, * f=20, and accel=1. * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. * The resulting dictionary will be saved into `dictBuffer`. * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) * or an error code, which can be tested with ZDICT_isError(). * Note: Dictionary training will fail if there are not enough samples to construct a * dictionary, or if most of the samples are too small (< 8 bytes being the lower limit). * If dictionary training fails, you should use zstd without a dictionary, as the dictionary * would've been ineffective anyways. If you believe your samples would benefit from a dictionary * please open an issue with details, and we can look into it. * Note: ZDICT_trainFromBuffer()'s memory usage is about 6 MB. * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. * In general, it's recommended to provide a few thousands samples, though this can vary a lot. * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. */ ZDICTLIB_API size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity, const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples); /*====== Helper functions ======*/ ZDICTLIB_API unsigned ZDICT_getDictID(const void* dictBuffer, size_t dictSize); /**< extracts dictID; @return zero if error (not a valid dictionary) */ ZDICTLIB_API unsigned ZDICT_isError(size_t errorCode); ZDICTLIB_API const char* ZDICT_getErrorName(size_t errorCode); #ifdef ZDICT_STATIC_LINKING_ONLY /* ==================================================================================== * The definitions in this section are considered experimental. * They should never be used with a dynamic library, as they may change in the future. * They are provided for advanced usages. * Use them only in association with static linking. * ==================================================================================== */ typedef struct { int compressionLevel; /* optimize for a specific zstd compression level; 0 means default */ unsigned notificationLevel; /* Write log to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */ unsigned dictID; /* force dictID value; 0 means auto mode (32-bits random value) */ } ZDICT_params_t; /*! ZDICT_cover_params_t: * k and d are the only required parameters. * For others, value 0 means default. */ typedef struct { unsigned k; /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */ unsigned d; /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */ unsigned steps; /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */ unsigned nbThreads; /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */ 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 */ 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 */ unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */ ZDICT_params_t zParams; } ZDICT_cover_params_t; typedef struct { unsigned k; /* Segment size : constraint: 0 < k : Reasonable range [16, 2048+] */ unsigned d; /* dmer size : constraint: 0 < d <= k : Reasonable range [6, 16] */ unsigned f; /* log of size of frequency array : constraint: 0 < f <= 31 : 1 means default(20)*/ unsigned steps; /* Number of steps : Only used for optimization : 0 means default (40) : Higher means more parameters checked */ unsigned nbThreads; /* Number of threads : constraint: 0 < nbThreads : 1 means single-threaded : Only used for optimization : Ignored if ZSTD_MULTITHREAD is not defined */ 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 */ unsigned accel; /* Acceleration level: constraint: 0 < accel <= 10, higher means faster and less accurate, 0 means default(1) */ 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 */ unsigned shrinkDictMaxRegression; /* Sets shrinkDictMaxRegression so that a smaller dictionary can be at worse shrinkDictMaxRegression% worse than the max dict size dictionary. */ ZDICT_params_t zParams; } ZDICT_fastCover_params_t; /*! ZDICT_trainFromBuffer_cover(): * Train a dictionary from an array of samples using the COVER algorithm. * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. * The resulting dictionary will be saved into `dictBuffer`. * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) * or an error code, which can be tested with ZDICT_isError(). * See ZDICT_trainFromBuffer() for details on failure modes. * Note: ZDICT_trainFromBuffer_cover() requires about 9 bytes of memory for each input byte. * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. * In general, it's recommended to provide a few thousands samples, though this can vary a lot. * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. */ ZDICTLIB_API size_t ZDICT_trainFromBuffer_cover( void *dictBuffer, size_t dictBufferCapacity, const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples, ZDICT_cover_params_t parameters); /*! ZDICT_optimizeTrainFromBuffer_cover(): * The same requirements as above hold for all the parameters except `parameters`. * This function tries many parameter combinations and picks the best parameters. * `*parameters` is filled with the best parameters found, * dictionary constructed with those parameters is stored in `dictBuffer`. * * All of the parameters d, k, steps are optional. * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}. * if steps is zero it defaults to its default value. * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000]. * * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) * or an error code, which can be tested with ZDICT_isError(). * On success `*parameters` contains the parameters selected. * See ZDICT_trainFromBuffer() for details on failure modes. * 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. */ ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_cover( void* dictBuffer, size_t dictBufferCapacity, const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples, ZDICT_cover_params_t* parameters); /*! ZDICT_trainFromBuffer_fastCover(): * Train a dictionary from an array of samples using a modified version of COVER algorithm. * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. * d and k are required. * All other parameters are optional, will use default values if not provided * The resulting dictionary will be saved into `dictBuffer`. * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) * or an error code, which can be tested with ZDICT_isError(). * See ZDICT_trainFromBuffer() for details on failure modes. * Note: ZDICT_trainFromBuffer_fastCover() requires 6 * 2^f bytes of memory. * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. * In general, it's recommended to provide a few thousands samples, though this can vary a lot. * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. */ ZDICTLIB_API size_t ZDICT_trainFromBuffer_fastCover(void *dictBuffer, size_t dictBufferCapacity, const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples, ZDICT_fastCover_params_t parameters); /*! ZDICT_optimizeTrainFromBuffer_fastCover(): * The same requirements as above hold for all the parameters except `parameters`. * This function tries many parameter combinations (specifically, k and d combinations) * and picks the best parameters. `*parameters` is filled with the best parameters found, * dictionary constructed with those parameters is stored in `dictBuffer`. * All of the parameters d, k, steps, f, and accel are optional. * If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8}. * if steps is zero it defaults to its default value. * If k is non-zero then we don't check multiple values of k, otherwise we check steps values in [50, 2000]. * If f is zero, default value of 20 is used. * If accel is zero, default value of 1 is used. * * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) * or an error code, which can be tested with ZDICT_isError(). * On success `*parameters` contains the parameters selected. * See ZDICT_trainFromBuffer() for details on failure modes. * Note: ZDICT_optimizeTrainFromBuffer_fastCover() requires about 6 * 2^f bytes of memory for each thread. */ ZDICTLIB_API size_t ZDICT_optimizeTrainFromBuffer_fastCover(void* dictBuffer, size_t dictBufferCapacity, const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples, ZDICT_fastCover_params_t* parameters); /*! ZDICT_finalizeDictionary(): * Given a custom content as a basis for dictionary, and a set of samples, * finalize dictionary by adding headers and statistics. * * Samples must be stored concatenated in a flat buffer `samplesBuffer`, * supplied with an array of sizes `samplesSizes`, providing the size of each sample in order. * * dictContentSize must be >= ZDICT_CONTENTSIZE_MIN bytes. * maxDictSize must be >= dictContentSize, and must be >= ZDICT_DICTSIZE_MIN bytes. * * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`), * or an error code, which can be tested by ZDICT_isError(). * Note: ZDICT_finalizeDictionary() will push notifications into stderr if instructed to, using notificationLevel>0. * Note 2: dictBuffer and dictContent can overlap */ #define ZDICT_CONTENTSIZE_MIN 128 #define ZDICT_DICTSIZE_MIN 256 ZDICTLIB_API size_t ZDICT_finalizeDictionary(void* dictBuffer, size_t dictBufferCapacity, const void* dictContent, size_t dictContentSize, const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples, ZDICT_params_t parameters); typedef struct { unsigned selectivityLevel; /* 0 means default; larger => select more => larger dictionary */ ZDICT_params_t zParams; } ZDICT_legacy_params_t; /*! ZDICT_trainFromBuffer_legacy(): * Train a dictionary from an array of samples. * Samples must be stored concatenated in a single flat buffer `samplesBuffer`, * supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order. * The resulting dictionary will be saved into `dictBuffer`. * `parameters` is optional and can be provided with values set to 0 to mean "default". * @return: size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`) * or an error code, which can be tested with ZDICT_isError(). * See ZDICT_trainFromBuffer() for details on failure modes. * Tips: In general, a reasonable dictionary has a size of ~ 100 KB. * It's possible to select smaller or larger size, just by specifying `dictBufferCapacity`. * In general, it's recommended to provide a few thousands samples, though this can vary a lot. * It's recommended that total size of all samples be about ~x100 times the target size of dictionary. * Note: ZDICT_trainFromBuffer_legacy() will send notifications into stderr if instructed to, using notificationLevel>0. */ ZDICTLIB_API size_t ZDICT_trainFromBuffer_legacy( void *dictBuffer, size_t dictBufferCapacity, const void *samplesBuffer, const size_t *samplesSizes, unsigned nbSamples, ZDICT_legacy_params_t parameters); /* Deprecation warnings */ /* It is generally possible to disable deprecation warnings from compiler, for example with -Wno-deprecated-declarations for gcc or _CRT_SECURE_NO_WARNINGS in Visual. Otherwise, it's also possible to manually define ZDICT_DISABLE_DEPRECATE_WARNINGS */ #ifdef ZDICT_DISABLE_DEPRECATE_WARNINGS # define ZDICT_DEPRECATED(message) ZDICTLIB_API /* disable deprecation warnings */ #else # define ZDICT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) # if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */ # define ZDICT_DEPRECATED(message) [[deprecated(message)]] ZDICTLIB_API # elif (ZDICT_GCC_VERSION >= 405) || defined(__clang__) # define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated(message))) # elif (ZDICT_GCC_VERSION >= 301) # define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated)) # elif defined(_MSC_VER) # define ZDICT_DEPRECATED(message) ZDICTLIB_API __declspec(deprecated(message)) # else # pragma message("WARNING: You need to implement ZDICT_DEPRECATED for this compiler") # define ZDICT_DEPRECATED(message) ZDICTLIB_API # endif #endif /* ZDICT_DISABLE_DEPRECATE_WARNINGS */ ZDICT_DEPRECATED("use ZDICT_finalizeDictionary() instead") size_t ZDICT_addEntropyTablesFromBuffer(void* dictBuffer, size_t dictContentSize, size_t dictBufferCapacity, const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples); #endif /* ZDICT_STATIC_LINKING_ONLY */ #if defined (__cplusplus) } #endif #endif /* DICTBUILDER_H_001 */
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