202 lines
10 KiB
C
202 lines
10 KiB
C
/**
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* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*/
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#ifndef DICTBUILDER_H_001
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#define DICTBUILDER_H_001
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#if defined (__cplusplus)
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extern "C" {
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#endif
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/*====== Dependencies ======*/
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#include <stddef.h> /* size_t */
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/* ===== ZDICTLIB_API : control library symbols visibility ===== */
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#if defined(__GNUC__) && (__GNUC__ >= 4)
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# define ZDICTLIB_VISIBILITY __attribute__ ((visibility ("default")))
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#else
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# define ZDICTLIB_VISIBILITY
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#endif
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#if defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
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# define ZDICTLIB_API __declspec(dllexport) ZDICTLIB_VISIBILITY
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#elif defined(ZSTD_DLL_IMPORT) && (ZSTD_DLL_IMPORT==1)
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# 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.*/
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#else
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# define ZDICTLIB_API ZDICTLIB_VISIBILITY
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#endif
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/*! ZDICT_trainFromBuffer() :
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Train a dictionary from an array of samples.
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Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
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supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
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The resulting dictionary will be saved into `dictBuffer`.
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@return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
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or an error code, which can be tested with ZDICT_isError().
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Tips : In general, a reasonable dictionary has a size of ~ 100 KB.
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It's obviously possible to target smaller or larger ones, just by specifying different `dictBufferCapacity`.
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In general, it's recommended to provide a few thousands samples, but this can vary a lot.
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It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
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*/
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ZDICTLIB_API size_t ZDICT_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
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const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples);
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/*====== Helper functions ======*/
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ZDICTLIB_API unsigned ZDICT_getDictID(const void* dictBuffer, size_t dictSize); /**< extracts dictID; @return zero if error (not a valid dictionary) */
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ZDICTLIB_API unsigned ZDICT_isError(size_t errorCode);
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ZDICTLIB_API const char* ZDICT_getErrorName(size_t errorCode);
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#ifdef ZDICT_STATIC_LINKING_ONLY
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/* ====================================================================================
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* The definitions in this section are considered experimental.
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* They should never be used with a dynamic library, as they may change in the future.
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* They are provided for advanced usages.
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* Use them only in association with static linking.
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* ==================================================================================== */
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typedef struct {
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unsigned selectivityLevel; /* 0 means default; larger => select more => larger dictionary */
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int compressionLevel; /* 0 means default; target a specific zstd compression level */
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unsigned notificationLevel; /* Write to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */
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unsigned dictID; /* 0 means auto mode (32-bits random value); other : force dictID value */
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unsigned reserved[2]; /* reserved space for future parameters */
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} ZDICT_params_t;
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/*! ZDICT_trainFromBuffer_advanced() :
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Same as ZDICT_trainFromBuffer() with control over more parameters.
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`parameters` is optional and can be provided with values set to 0 to mean "default".
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@return : size of dictionary stored into `dictBuffer` (<= `dictBufferSize`),
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or an error code, which can be tested by ZDICT_isError().
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note : ZDICT_trainFromBuffer_advanced() will send notifications into stderr if instructed to, using notificationLevel>0.
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*/
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ZDICTLIB_API size_t ZDICT_trainFromBuffer_advanced(void* dictBuffer, size_t dictBufferCapacity,
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const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
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ZDICT_params_t parameters);
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/*! COVER_params_t :
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For all values 0 means default.
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kMin and d are the only required parameters.
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*/
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typedef struct {
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unsigned d; /* dmer size : constraint: <= kMin : Should probably be in the range [6, 16]. */
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unsigned kMin; /* Minimum segment size : constraint: > 0 */
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unsigned kStep; /* Try kStep segment lengths uniformly distributed in the range [kMin, kMax] : 0 (default) only if kMax == 0 */
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unsigned kMax; /* Maximum segment size : 0 = kMin (default) : constraint : 0 or >= kMin */
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unsigned smoothing; /* Higher smoothing => larger segments are selected. Only useful if kMax > kMin. */
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unsigned notificationLevel; /* Write to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */
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unsigned dictID; /* 0 means auto mode (32-bits random value); other : force dictID value */
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int compressionLevel; /* 0 means default; target a specific zstd compression level */
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} COVER_params_t;
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/*! COVER_trainFromBuffer() :
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Train a dictionary from an array of samples using the COVER algorithm.
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Samples must be stored concatenated in a single flat buffer `samplesBuffer`,
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supplied with an array of sizes `samplesSizes`, providing the size of each sample, in order.
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The resulting dictionary will be saved into `dictBuffer`.
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@return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
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or an error code, which can be tested with ZDICT_isError().
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Tips : In general, a reasonable dictionary has a size of ~ 100 KB.
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It's obviously possible to target smaller or larger ones, just by specifying different `dictBufferCapacity`.
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In general, it's recommended to provide a few thousands samples, but this can vary a lot.
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It's recommended that total size of all samples be about ~x100 times the target size of dictionary.
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*/
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ZDICTLIB_API size_t COVER_trainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
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const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
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COVER_params_t parameters);
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/*! COVER_optimizeTrainFromBuffer() :
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The same requirements as above hold for all the parameters except `parameters`.
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This function tries many parameter combinations and picks the best parameters.
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`*parameters` is filled with the best parameters found, and the dictionary
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constructed with those parameters is stored in `dictBuffer`.
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All of the {d, kMin, kStep, kMax} are optional, and smoothing is ignored.
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If d is non-zero then we don't check multiple values of d, otherwise we check d = {6, 8, 10, 12, 14, 16}.
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If kStep is non-zero then it is used, otherwise we pick 8.
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If kMin and kMax are non-zero, then they limit the search space for kMin and kMax,
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otherwise we check kMin and kMax values in the range [32, 1024].
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@return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`)
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or an error code, which can be tested with ZDICT_isError().
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On success `*parameters` contains the parameters selected.
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*/
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ZDICTLIB_API size_t COVER_optimizeTrainFromBuffer(void* dictBuffer, size_t dictBufferCapacity,
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const void* samplesBuffer, const size_t *samplesSizes, unsigned nbSamples,
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COVER_params_t *parameters);
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/*! ZDICT_finalizeDictionary() :
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Given a custom content as a basis for dictionary, and a set of samples,
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finalize dictionary by adding headers and statistics.
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Samples must be stored concatenated in a flat buffer `samplesBuffer`,
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supplied with an array of sizes `samplesSizes`, providing the size of each sample in order.
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dictContentSize must be > ZDICT_CONTENTSIZE_MIN bytes.
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maxDictSize must be >= dictContentSize, and must be > ZDICT_DICTSIZE_MIN bytes.
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@return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`),
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or an error code, which can be tested by ZDICT_isError().
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note : ZDICT_finalizeDictionary() will push notifications into stderr if instructed to, using notificationLevel>0.
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note 2 : dictBuffer and customDictContent can overlap
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*/
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#define ZDICT_CONTENTSIZE_MIN 256
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#define ZDICT_DICTSIZE_MIN 512
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ZDICTLIB_API size_t ZDICT_finalizeDictionary(void* dictBuffer, size_t dictBufferCapacity,
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const void* customDictContent, size_t dictContentSize,
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const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
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ZDICT_params_t parameters);
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/* Deprecation warnings */
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/* It is generally possible to disable deprecation warnings from compiler,
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for example with -Wno-deprecated-declarations for gcc
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or _CRT_SECURE_NO_WARNINGS in Visual.
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Otherwise, it's also possible to manually define ZDICT_DISABLE_DEPRECATE_WARNINGS */
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#ifdef ZDICT_DISABLE_DEPRECATE_WARNINGS
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# define ZDICT_DEPRECATED(message) ZDICTLIB_API /* disable deprecation warnings */
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#else
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# define ZDICT_GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
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# if defined (__cplusplus) && (__cplusplus >= 201402) /* C++14 or greater */
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# define ZDICT_DEPRECATED(message) ZDICTLIB_API [[deprecated(message)]]
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# elif (ZDICT_GCC_VERSION >= 405) || defined(__clang__)
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# define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated(message)))
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# elif (ZDICT_GCC_VERSION >= 301)
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# define ZDICT_DEPRECATED(message) ZDICTLIB_API __attribute__((deprecated))
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# elif defined(_MSC_VER)
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# define ZDICT_DEPRECATED(message) ZDICTLIB_API __declspec(deprecated(message))
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# else
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# pragma message("WARNING: You need to implement ZDICT_DEPRECATED for this compiler")
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# define ZDICT_DEPRECATED(message) ZDICTLIB_API
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# endif
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#endif /* ZDICT_DISABLE_DEPRECATE_WARNINGS */
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ZDICT_DEPRECATED("use ZDICT_finalizeDictionary() instead")
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size_t ZDICT_addEntropyTablesFromBuffer(void* dictBuffer, size_t dictContentSize, size_t dictBufferCapacity,
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const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples);
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#endif /* ZDICT_STATIC_LINKING_ONLY */
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#if defined (__cplusplus)
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}
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#endif
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#endif /* DICTBUILDER_H_001 */
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