9f8ed23b5b
also added a paragraph on using compression level with training mode as this is a recurrent question (see for example #1004)
213 lines
11 KiB
C
213 lines
11 KiB
C
/*
|
|
* 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_cover() single-threaded, with d=8 and steps=4.
|
|
* 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: ZDICT_trainFromBuffer() 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(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 (32) : 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 */
|
|
ZDICT_params_t zParams;
|
|
} ZDICT_cover_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().
|
|
* 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, 10, 12, 14, 16}.
|
|
* 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 [16, 2048].
|
|
*
|
|
* @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.
|
|
* 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_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().
|
|
* 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 */
|