172 lines
8.7 KiB
C
172 lines
8.7 KiB
C
/*
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Buffered version of Zstd compression library
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Copyright (C) 2015, Yann Collet.
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BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following disclaimer
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in the documentation and/or other materials provided with the
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distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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You can contact the author at :
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- zstd source repository : https://github.com/Cyan4973/zstd
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- ztsd public forum : https://groups.google.com/forum/#!forum/lz4c
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*/
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#ifndef ZSTD_BUFFERED_H
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#define ZSTD_BUFFERED_H
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/* The objects defined into this file should be considered experimental.
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* They are not labelled stable, as their prototype may change in the future.
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* You can use them for tests, provide feedback, or if you can endure risk of future changes.
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*/
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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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* Includes
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***************************************/
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#include <stddef.h> /* size_t */
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/* ***************************************************************
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* Tuning parameters
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*****************************************************************/
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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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*/
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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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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_compressWithDictionary(ZBUFF_CCtx* cctx, const void* src, size_t srcSize);
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ZSTDLIB_API size_t ZBUFF_compressContinue(ZBUFF_CCtx* cctx, void* dst, size_t* maxDstSizePtr, const void* src, size_t* srcSizePtr);
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ZSTDLIB_API size_t ZBUFF_compressFlush(ZBUFF_CCtx* cctx, void* dst, size_t* maxDstSizePtr);
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ZSTDLIB_API size_t ZBUFF_compressEnd(ZBUFF_CCtx* cctx, void* dst, size_t* maxDstSizePtr);
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/** ************************************************
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* Streaming compression
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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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* Use ZBUFF_compressInit() to start a new compression operation.
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* ZBUFF_CCtx objects can be reused multiple times.
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*
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* Optionally, a reference to a static dictionary can be created with ZBUFF_compressWithDictionary()
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* Note that the dictionary content must remain accessible during the compression process.
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*
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* Use ZBUFF_compressContinue() repetitively to consume input stream.
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* *srcSizePtr and *maxDstSizePtr can be any size.
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* The function will report how many bytes were read or written within *srcSizePtr and *maxDstSizePtr.
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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 *maxDstSizePtr) at each function call, so save its content if it matters or move dst .
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* @return : a hint to preferred nb of bytes to use as input for next function call (it's only 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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* ZBUFF_compressFlush() can be used to instruct ZBUFF to compress and output whatever remains within its buffer.
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* Note that it will not output more than *maxDstSizePtr.
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* Therefore, some content might still be left into its internal buffer if dst buffer 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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* Note that the epilogue is necessary 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 *maxDstSizePtr 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, it improves latency to use this value.
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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, you ensure that input will be entirely consumed, and output will always contain the result.
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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_decompressWithDictionary(ZBUFF_DCtx* dctx, const void* src, size_t srcSize);
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ZSTDLIB_API size_t ZBUFF_decompressContinue(ZBUFF_DCtx* dctx, void* dst, size_t* maxDstSizePtr, const void* src, size_t* srcSizePtr);
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/** ************************************************
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* Streaming decompression
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*
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* A ZBUFF_DCtx object is required to track streaming operation.
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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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* ZBUFF_DCtx objects can be reused multiple times.
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*
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* Optionally, a reference to a static dictionary can be set, using ZBUFF_decompressWithDictionary()
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* It must be the same content as the one set during compression phase.
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* Dictionary content must remain accessible during the decompression process.
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*
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* Use ZBUFF_decompressContinue() repetitively to consume your input.
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* *srcSizePtr and *maxDstSizePtr can be any size.
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* The function will report how many bytes were read or written by modifying *srcSizePtr and *maxDstSizePtr.
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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 *maxDstSizePtr) at each function 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 only a hint, to improve latency)
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* or 0 when a frame is completely decoded
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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 / 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 it's decoded.
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* input : ZBUFF_recommendedDInSize==128Kb+3; 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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/** The below functions provide recommended buffer sizes for Compression or Decompression operations.
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* These sizes are not compulsory, they just 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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#if defined (__cplusplus)
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}
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#endif
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#endif /* ZSTD_BUFFERED_H */
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