112 lines
4.8 KiB
C
112 lines
4.8 KiB
C
/**
|
|
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This source code is licensed under the BSD-style license found in the
|
|
* LICENSE file in the root directory of this source tree. An additional grant
|
|
* of patent rights can be found in the PATENTS file in the same directory.
|
|
*/
|
|
|
|
#ifndef DICTBUILDER_H_001
|
|
#define DICTBUILDER_H_001
|
|
|
|
#if defined (__cplusplus)
|
|
extern "C" {
|
|
#endif
|
|
|
|
|
|
/*====== Dependencies ======*/
|
|
#include <stddef.h> /* size_t */
|
|
|
|
|
|
/*====== Export for Windows ======*/
|
|
/*!
|
|
* ZSTD_DLL_EXPORT :
|
|
* Enable exporting of functions when building a Windows DLL
|
|
*/
|
|
#if defined(_WIN32) && defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
|
|
# define ZDICTLIB_API __declspec(dllexport)
|
|
#else
|
|
# define ZDICTLIB_API
|
|
#endif
|
|
|
|
|
|
/*! ZDICT_trainFromBuffer() :
|
|
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`.
|
|
@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 obviously possible to target smaller or larger ones, just by specifying different `dictBufferCapacity`.
|
|
In general, it's recommended to provide a few thousands samples, but 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 {
|
|
unsigned selectivityLevel; /* 0 means default; larger => select more => larger dictionary */
|
|
int compressionLevel; /* 0 means default; target a specific zstd compression level */
|
|
unsigned notificationLevel; /* Write to stderr; 0 = none (default); 1 = errors; 2 = progression; 3 = details; 4 = debug; */
|
|
unsigned dictID; /* 0 means auto mode (32-bits random value); other : force dictID value */
|
|
unsigned reserved[2]; /* space for future parameters */
|
|
} ZDICT_params_t;
|
|
|
|
|
|
/*! ZDICT_trainFromBuffer_advanced() :
|
|
Same as ZDICT_trainFromBuffer() with control over more parameters.
|
|
`parameters` is optional and can be provided with values set to 0 to mean "default".
|
|
@return : size of dictionary stored into `dictBuffer` (<= `dictBufferSize`),
|
|
or an error code, which can be tested by ZDICT_isError().
|
|
note : ZDICT_trainFromBuffer_advanced() will send notifications into stderr if instructed to, using notificationLevel>0.
|
|
*/
|
|
size_t ZDICT_trainFromBuffer_advanced(void* dictBuffer, size_t dictBufferCapacity,
|
|
const void* samplesBuffer, const size_t* samplesSizes, unsigned nbSamples,
|
|
ZDICT_params_t parameters);
|
|
|
|
|
|
/*! ZDICT_addEntropyTablesFromBuffer() :
|
|
|
|
Given a content-only dictionary (built using any 3rd party algorithm),
|
|
add entropy tables computed from an array of samples.
|
|
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.
|
|
|
|
The input dictionary content must be stored *at the end* of `dictBuffer`.
|
|
Its size is `dictContentSize`.
|
|
The resulting dictionary with added entropy tables will be *written back to `dictBuffer`*,
|
|
starting from its beginning.
|
|
@return : size of dictionary stored into `dictBuffer` (<= `dictBufferCapacity`).
|
|
*/
|
|
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 */
|