292 lines
12 KiB
C
292 lines
12 KiB
C
/*
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Buffered version of Zstd compression library
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Copyright (C) 2015-2016, 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 homepage : http://www.zstd.net/
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*/
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/* *************************************
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* Dependencies
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***************************************/
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#include <stdlib.h>
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#include "error_private.h"
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#include "zstd_internal.h" /* MIN, ZSTD_blockHeaderSize */
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#include "zstd_static.h" /* ZSTD_BLOCKSIZE_MAX */
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#include "zbuff_static.h"
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/* *************************************
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* Constants
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***************************************/
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static size_t const ZBUFF_endFrameSize = ZSTD_BLOCKHEADERSIZE;
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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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* Use ZBUFF_compressContinue() 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 call again the function with remaining input.
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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 : 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 *dstCapacityPtr.
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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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* 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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* @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)
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* input : ZSTD_BLOCKSIZE_MAX (128 KB), internal unit size, it improves latency to use this value.
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* output : ZSTD_compressBound(ZSTD_BLOCKSIZE_MAX) + ZSTD_blockHeaderSize + ZBUFF_endFrameSize : ensures it's always possible to write/flush/end a full block at best speed.
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* **************************************************/
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typedef enum { ZBUFFcs_init, ZBUFFcs_load, ZBUFFcs_flush } ZBUFF_cStage;
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/* *** Ressources *** */
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struct ZBUFF_CCtx_s {
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ZSTD_CCtx* zc;
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char* inBuff;
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size_t inBuffSize;
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size_t inToCompress;
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size_t inBuffPos;
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size_t inBuffTarget;
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size_t blockSize;
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char* outBuff;
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size_t outBuffSize;
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size_t outBuffContentSize;
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size_t outBuffFlushedSize;
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ZBUFF_cStage stage;
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}; /* typedef'd tp ZBUFF_CCtx within "zstd_buffered.h" */
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ZBUFF_CCtx* ZBUFF_createCCtx(void)
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{
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ZBUFF_CCtx* zbc = (ZBUFF_CCtx*)malloc(sizeof(ZBUFF_CCtx));
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if (zbc==NULL) return NULL;
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memset(zbc, 0, sizeof(*zbc));
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zbc->zc = ZSTD_createCCtx();
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return zbc;
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}
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size_t ZBUFF_freeCCtx(ZBUFF_CCtx* zbc)
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{
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if (zbc==NULL) return 0; /* support free on NULL */
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ZSTD_freeCCtx(zbc->zc);
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free(zbc->inBuff);
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free(zbc->outBuff);
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free(zbc);
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return 0;
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}
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/* *** Initialization *** */
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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, U64 pledgedSrcSize)
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{
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/* allocate buffers */
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{ size_t const neededInBuffSize = (size_t)1 << params.cParams.windowLog;
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if (zbc->inBuffSize < neededInBuffSize) {
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zbc->inBuffSize = neededInBuffSize;
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free(zbc->inBuff); /* should not be necessary */
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zbc->inBuff = (char*)malloc(neededInBuffSize);
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if (zbc->inBuff == NULL) return ERROR(memory_allocation);
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}
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zbc->blockSize = MIN(ZSTD_BLOCKSIZE_MAX, neededInBuffSize/2);
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}
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if (zbc->outBuffSize < ZSTD_compressBound(zbc->blockSize)+1) {
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zbc->outBuffSize = ZSTD_compressBound(zbc->blockSize)+1;
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free(zbc->outBuff); /* should not be necessary */
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zbc->outBuff = (char*)malloc(zbc->outBuffSize);
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if (zbc->outBuff == NULL) return ERROR(memory_allocation);
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}
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{ size_t const errorCode = ZSTD_compressBegin_advanced(zbc->zc, dict, dictSize, params, pledgedSrcSize);
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if (ZSTD_isError(errorCode)) return errorCode; }
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zbc->inToCompress = 0;
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zbc->inBuffPos = 0;
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zbc->inBuffTarget = zbc->blockSize;
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zbc->outBuffFlushedSize = 0;
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zbc->stage = ZBUFFcs_load;
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return 0; /* ready to go */
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}
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size_t ZBUFF_compressInitDictionary(ZBUFF_CCtx* zbc, const void* dict, size_t dictSize, int compressionLevel)
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{
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ZSTD_parameters params;
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params.cParams = ZSTD_getCParams(compressionLevel, 0, dictSize);
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params.fParams.contentSizeFlag = 0;
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ZSTD_adjustCParams(¶ms.cParams, 0, dictSize);
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return ZBUFF_compressInit_advanced(zbc, dict, dictSize, params, 0);
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}
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size_t ZBUFF_compressInit(ZBUFF_CCtx* zbc, int compressionLevel)
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{
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return ZBUFF_compressInitDictionary(zbc, NULL, 0, compressionLevel);
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}
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/* *** Compression *** */
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static size_t ZBUFF_compressContinue_generic(ZBUFF_CCtx* zbc,
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void* dst, size_t* dstCapacityPtr,
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const void* src, size_t* srcSizePtr,
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int flush) /* aggregate : wait for full block before compressing */
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{
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U32 notDone = 1;
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const char* const istart = (const char*)src;
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const char* const iend = istart + *srcSizePtr;
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const char* ip = istart;
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char* const ostart = (char*)dst;
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char* const oend = ostart + *dstCapacityPtr;
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char* op = ostart;
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while (notDone) {
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switch(zbc->stage)
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{
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case ZBUFFcs_init: return ERROR(init_missing); /* call ZBUFF_compressInit() first ! */
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case ZBUFFcs_load:
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/* complete inBuffer */
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{ size_t const toLoad = zbc->inBuffTarget - zbc->inBuffPos;
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size_t const loaded = ZBUFF_limitCopy(zbc->inBuff + zbc->inBuffPos, toLoad, ip, iend-ip);
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zbc->inBuffPos += loaded;
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ip += loaded;
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if ( (zbc->inBuffPos==zbc->inToCompress) || (!flush && (toLoad != loaded)) ) {
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notDone = 0; break; /* not enough input to get a full block : stop there, wait for more */
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} }
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/* compress current block (note : this stage cannot be stopped in the middle) */
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{ void* cDst;
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size_t cSize;
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size_t const iSize = zbc->inBuffPos - zbc->inToCompress;
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size_t oSize = oend-op;
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if (oSize >= ZSTD_compressBound(iSize))
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cDst = op; /* compress directly into output buffer (avoid flush stage) */
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else
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cDst = zbc->outBuff, oSize = zbc->outBuffSize;
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cSize = ZSTD_compressContinue(zbc->zc, cDst, oSize, zbc->inBuff + zbc->inToCompress, iSize);
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if (ZSTD_isError(cSize)) return cSize;
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/* prepare next block */
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zbc->inBuffTarget = zbc->inBuffPos + zbc->blockSize;
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if (zbc->inBuffTarget > zbc->inBuffSize)
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zbc->inBuffPos = 0, zbc->inBuffTarget = zbc->blockSize; /* note : inBuffSize >= blockSize */
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zbc->inToCompress = zbc->inBuffPos;
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if (cDst == op) { op += cSize; break; } /* no need to flush */
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zbc->outBuffContentSize = cSize;
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zbc->outBuffFlushedSize = 0;
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zbc->stage = ZBUFFcs_flush; /* continue to flush stage */
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}
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case ZBUFFcs_flush:
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/* flush into dst */
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{ size_t const toFlush = zbc->outBuffContentSize - zbc->outBuffFlushedSize;
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size_t const flushed = ZBUFF_limitCopy(op, oend-op, zbc->outBuff + zbc->outBuffFlushedSize, toFlush);
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op += flushed;
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zbc->outBuffFlushedSize += flushed;
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if (toFlush!=flushed) { notDone = 0; break; } /* not enough space within dst to store compressed block : stop there */
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zbc->outBuffContentSize = 0;
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zbc->outBuffFlushedSize = 0;
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zbc->stage = ZBUFFcs_load;
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break;
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}
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default:
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return ERROR(GENERIC); /* impossible */
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}
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}
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*srcSizePtr = ip - istart;
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*dstCapacityPtr = op - ostart;
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{ size_t hintInSize = zbc->inBuffTarget - zbc->inBuffPos;
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if (hintInSize==0) hintInSize = zbc->blockSize;
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return hintInSize;
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}
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}
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size_t ZBUFF_compressContinue(ZBUFF_CCtx* zbc,
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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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return ZBUFF_compressContinue_generic(zbc, dst, dstCapacityPtr, src, srcSizePtr, 0);
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}
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/* *** Finalize *** */
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size_t ZBUFF_compressFlush(ZBUFF_CCtx* zbc, void* dst, size_t* dstCapacityPtr)
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{
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size_t srcSize = 0;
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ZBUFF_compressContinue_generic(zbc, dst, dstCapacityPtr, &srcSize, &srcSize, 1); /* use a valid src address instead of NULL */
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return zbc->outBuffContentSize - zbc->outBuffFlushedSize;
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}
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size_t ZBUFF_compressEnd(ZBUFF_CCtx* zbc, void* dst, size_t* dstCapacityPtr)
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{
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BYTE* const ostart = (BYTE*)dst;
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BYTE* const oend = ostart + *dstCapacityPtr;
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BYTE* op = ostart;
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size_t outSize = *dstCapacityPtr;
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size_t epilogueSize, remaining;
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ZBUFF_compressFlush(zbc, dst, &outSize); /* flush any remaining inBuff */
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op += outSize;
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epilogueSize = ZSTD_compressEnd(zbc->zc, zbc->outBuff + zbc->outBuffContentSize, zbc->outBuffSize - zbc->outBuffContentSize); /* epilogue into outBuff */
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zbc->outBuffContentSize += epilogueSize;
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outSize = oend-op;
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zbc->stage = ZBUFFcs_flush;
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remaining = ZBUFF_compressFlush(zbc, op, &outSize); /* attempt to flush epilogue into dst */
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op += outSize;
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if (!remaining) zbc->stage = ZBUFFcs_init; /* close only if nothing left to flush */
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*dstCapacityPtr = op-ostart; /* tells how many bytes were written */
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return remaining;
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}
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/* *************************************
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* Tool functions
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***************************************/
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size_t ZBUFF_recommendedCInSize(void) { return ZSTD_BLOCKSIZE_MAX; }
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size_t ZBUFF_recommendedCOutSize(void) { return ZSTD_compressBound(ZSTD_BLOCKSIZE_MAX) + ZSTD_blockHeaderSize + ZBUFF_endFrameSize; }
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