mirror of
https://github.com/facebook/zstd.git
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184 lines
9.0 KiB
C
184 lines
9.0 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 ZSTD_BUFFERED_H_23987
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#define ZSTD_BUFFERED_H_23987
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#if defined (__cplusplus)
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extern "C" {
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#endif
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/* *************************************
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* Dependencies
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***************************************/
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#include <stddef.h> /* size_t */
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/* ***************************************************************
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* Compiler specifics
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*****************************************************************/
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/* ZSTD_DLL_EXPORT :
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* Enable exporting of functions when building a Windows DLL */
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#if defined(_WIN32) && defined(ZSTD_DLL_EXPORT) && (ZSTD_DLL_EXPORT==1)
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# define ZSTDLIB_API __declspec(dllexport)
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#else
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# define ZSTDLIB_API
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#endif
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/* *************************************
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* Streaming functions
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***************************************/
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/* This is the easier "buffered" streaming API,
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* using an internal buffer to lift all restrictions on user-provided buffers
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* which can be any size, any place, for both input and output.
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* ZBUFF and ZSTD are 100% interoperable,
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* frames created by one can be decoded by the other one */
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typedef struct ZBUFF_CCtx_s ZBUFF_CCtx;
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ZSTDLIB_API ZBUFF_CCtx* ZBUFF_createCCtx(void);
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ZSTDLIB_API size_t ZBUFF_freeCCtx(ZBUFF_CCtx* cctx);
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ZSTDLIB_API size_t ZBUFF_compressInit(ZBUFF_CCtx* cctx, int compressionLevel);
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ZSTDLIB_API size_t ZBUFF_compressInitDictionary(ZBUFF_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel);
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ZSTDLIB_API size_t ZBUFF_compressContinue(ZBUFF_CCtx* cctx, void* dst, size_t* dstCapacityPtr, const void* src, size_t* srcSizePtr);
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ZSTDLIB_API size_t ZBUFF_compressFlush(ZBUFF_CCtx* cctx, void* dst, size_t* dstCapacityPtr);
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ZSTDLIB_API size_t ZBUFF_compressEnd(ZBUFF_CCtx* cctx, void* dst, size_t* dstCapacityPtr);
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/*-*************************************************
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* Streaming compression - howto
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*
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* A ZBUFF_CCtx object is required to track streaming operation.
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* Use ZBUFF_createCCtx() and ZBUFF_freeCCtx() to create/release resources.
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* ZBUFF_CCtx objects can be reused multiple times.
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*
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* Start by initializing ZBUF_CCtx.
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* Use ZBUFF_compressInit() to start a new compression operation.
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* Use ZBUFF_compressInitDictionary() for a compression which requires a dictionary.
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*
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* Use ZBUFF_compressContinue() repetitively to consume input stream.
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* *srcSizePtr and *dstCapacityPtr can be any size.
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* The function will report how many bytes were read or written within *srcSizePtr and *dstCapacityPtr.
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* Note that it may not consume the entire input, in which case it's up to the caller to present again remaining data.
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* The content of `dst` will be overwritten (up to *dstCapacityPtr) at each call, so save its content if it matters or change @dst .
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* @return : a hint to preferred nb of bytes to use as input for next function call (it's just a hint, to improve latency)
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* or an error code, which can be tested using ZBUFF_isError().
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*
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* At any moment, it's possible to flush whatever data remains within buffer, using ZBUFF_compressFlush().
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* The nb of bytes written into `dst` will be reported into *dstCapacityPtr.
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* Note that the function cannot output more than *dstCapacityPtr,
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* therefore, some content might still be left into internal buffer if *dstCapacityPtr is too small.
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* @return : nb of bytes still present into internal buffer (0 if it's empty)
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* or an error code, which can be tested using ZBUFF_isError().
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*
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* ZBUFF_compressEnd() instructs to finish a frame.
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* It will perform a flush and write frame epilogue.
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* The epilogue is required for decoders to consider a frame completed.
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* Similar to ZBUFF_compressFlush(), it may not be able to output the entire internal buffer content if *dstCapacityPtr is too small.
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* In which case, call again ZBUFF_compressFlush() to complete the flush.
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* @return : nb of bytes still present into internal buffer (0 if it's empty)
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* or an error code, which can be tested using ZBUFF_isError().
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*
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* Hint : _recommended buffer_ sizes (not compulsory) : ZBUFF_recommendedCInSize() / ZBUFF_recommendedCOutSize()
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* input : ZBUFF_recommendedCInSize==128 KB block size is the internal unit, use this value to reduce intermediate stages (better latency)
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* output : ZBUFF_recommendedCOutSize==ZSTD_compressBound(128 KB) + 3 + 3 : ensures it's always possible to write/flush/end a full block. Skip some buffering.
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* By using both, it ensures that input will be entirely consumed, and output will always contain the result, reducing intermediate buffering.
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* **************************************************/
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typedef struct ZBUFF_DCtx_s ZBUFF_DCtx;
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ZSTDLIB_API ZBUFF_DCtx* ZBUFF_createDCtx(void);
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ZSTDLIB_API size_t ZBUFF_freeDCtx(ZBUFF_DCtx* dctx);
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ZSTDLIB_API size_t ZBUFF_decompressInit(ZBUFF_DCtx* dctx);
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ZSTDLIB_API size_t ZBUFF_decompressInitDictionary(ZBUFF_DCtx* dctx, const void* dict, size_t dictSize);
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ZSTDLIB_API size_t ZBUFF_decompressContinue(ZBUFF_DCtx* dctx,
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void* dst, size_t* dstCapacityPtr,
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const void* src, size_t* srcSizePtr);
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/*-***************************************************************************
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* Streaming decompression howto
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*
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* A ZBUFF_DCtx object is required to track streaming operations.
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* Use ZBUFF_createDCtx() and ZBUFF_freeDCtx() to create/release resources.
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* Use ZBUFF_decompressInit() to start a new decompression operation,
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* or ZBUFF_decompressInitDictionary() if decompression requires a dictionary.
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* Note that ZBUFF_DCtx objects can be re-init multiple times.
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*
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* Use ZBUFF_decompressContinue() repetitively to consume your input.
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* *srcSizePtr and *dstCapacityPtr can be any size.
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* The function will report how many bytes were read or written by modifying *srcSizePtr and *dstCapacityPtr.
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* Note that it may not consume the entire input, in which case it's up to the caller to present remaining input again.
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* The content of `dst` will be overwritten (up to *dstCapacityPtr) at each function call, so save its content if it matters, or change `dst`.
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* @return : 0 when a frame is completely decoded and fully flushed,
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* 1 when there is still some data left within internal buffer to flush,
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* >1 when more data is expected, with value being a suggested next input size (it's just a hint, which helps latency),
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* or an error code, which can be tested using ZBUFF_isError().
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*
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* Hint : recommended buffer sizes (not compulsory) : ZBUFF_recommendedDInSize() and ZBUFF_recommendedDOutSize()
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* output : ZBUFF_recommendedDOutSize== 128 KB block size is the internal unit, it ensures it's always possible to write a full block when decoded.
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* input : ZBUFF_recommendedDInSize == 128KB + 3;
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* just follow indications from ZBUFF_decompressContinue() to minimize latency. It should always be <= 128 KB + 3 .
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* *******************************************************************************/
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/* *************************************
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* Tool functions
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***************************************/
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ZSTDLIB_API unsigned ZBUFF_isError(size_t errorCode);
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ZSTDLIB_API const char* ZBUFF_getErrorName(size_t errorCode);
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/** Functions below provide recommended buffer sizes for Compression or Decompression operations.
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* These sizes are just hints, they tend to offer better latency */
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ZSTDLIB_API size_t ZBUFF_recommendedCInSize(void);
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ZSTDLIB_API size_t ZBUFF_recommendedCOutSize(void);
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ZSTDLIB_API size_t ZBUFF_recommendedDInSize(void);
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ZSTDLIB_API size_t ZBUFF_recommendedDOutSize(void);
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#ifdef ZBUFF_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 in association 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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/*--- Dependency ---*/
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#define ZSTD_STATIC_LINKING_ONLY /* ZSTD_parameters, ZSTD_customMem */
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#include "zstd.h"
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/*--- Custom memory allocator ---*/
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/*! ZBUFF_createCCtx_advanced() :
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* Create a ZBUFF compression context using external alloc and free functions */
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ZSTDLIB_API ZBUFF_CCtx* ZBUFF_createCCtx_advanced(ZSTD_customMem customMem);
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/*! ZBUFF_createDCtx_advanced() :
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* Create a ZBUFF decompression context using external alloc and free functions */
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ZSTDLIB_API ZBUFF_DCtx* ZBUFF_createDCtx_advanced(ZSTD_customMem customMem);
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/*--- Advanced Streaming Initialization ---*/
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ZSTDLIB_API size_t ZBUFF_compressInit_advanced(ZBUFF_CCtx* zbc,
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const void* dict, size_t dictSize,
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ZSTD_parameters params, unsigned long long pledgedSrcSize);
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#endif /* ZBUFF_STATIC_LINKING_ONLY */
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#if defined (__cplusplus)
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}
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#endif
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#endif /* ZSTD_BUFFERED_H_23987 */
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