zstd/lib/decompress/zbuff_decompress.c

253 lines
10 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.
*/
/* *************************************
* Dependencies
***************************************/
#include <stdlib.h>
#include "error_private.h"
#include "zstd_internal.h" /* MIN, ZSTD_blockHeaderSize, ZSTD_BLOCKSIZE_MAX */
#define ZBUFF_STATIC_LINKING_ONLY
#include "zbuff.h"
typedef enum { ZBUFFds_init, ZBUFFds_loadHeader,
ZBUFFds_read, ZBUFFds_load, ZBUFFds_flush } ZBUFF_dStage;
/* *** Resource management *** */
struct ZBUFF_DCtx_s {
ZSTD_DCtx* zd;
ZSTD_frameParams fParams;
ZBUFF_dStage stage;
char* inBuff;
size_t inBuffSize;
size_t inPos;
char* outBuff;
size_t outBuffSize;
size_t outStart;
size_t outEnd;
size_t blockSize;
BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
size_t lhSize;
ZSTD_customMem customMem;
}; /* typedef'd to ZBUFF_DCtx within "zbuff.h" */
ZBUFF_DCtx* ZBUFF_createDCtx(void)
{
return ZBUFF_createDCtx_advanced(defaultCustomMem);
}
ZBUFF_DCtx* ZBUFF_createDCtx_advanced(ZSTD_customMem customMem)
{
ZBUFF_DCtx* zbd;
if (!customMem.customAlloc && !customMem.customFree)
customMem = defaultCustomMem;
if (!customMem.customAlloc || !customMem.customFree)
return NULL;
zbd = (ZBUFF_DCtx*)customMem.customAlloc(customMem.opaque, sizeof(ZBUFF_DCtx));
if (zbd==NULL) return NULL;
memset(zbd, 0, sizeof(ZBUFF_DCtx));
memcpy(&zbd->customMem, &customMem, sizeof(ZSTD_customMem));
zbd->zd = ZSTD_createDCtx_advanced(customMem);
if (zbd->zd == NULL) { ZBUFF_freeDCtx(zbd); return NULL; }
zbd->stage = ZBUFFds_init;
return zbd;
}
size_t ZBUFF_freeDCtx(ZBUFF_DCtx* zbd)
{
if (zbd==NULL) return 0; /* support free on null */
ZSTD_freeDCtx(zbd->zd);
if (zbd->inBuff) zbd->customMem.customFree(zbd->customMem.opaque, zbd->inBuff);
if (zbd->outBuff) zbd->customMem.customFree(zbd->customMem.opaque, zbd->outBuff);
zbd->customMem.customFree(zbd->customMem.opaque, zbd);
return 0;
}
/* *** Initialization *** */
size_t ZBUFF_decompressInitDictionary(ZBUFF_DCtx* zbd, const void* dict, size_t dictSize)
{
zbd->stage = ZBUFFds_loadHeader;
zbd->lhSize = zbd->inPos = zbd->outStart = zbd->outEnd = 0;
return ZSTD_decompressBegin_usingDict(zbd->zd, dict, dictSize);
}
size_t ZBUFF_decompressInit(ZBUFF_DCtx* zbd)
{
return ZBUFF_decompressInitDictionary(zbd, NULL, 0);
}
/* internal util function */
MEM_STATIC size_t ZBUFF_limitCopy(void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
size_t const length = MIN(dstCapacity, srcSize);
memcpy(dst, src, length);
return length;
}
/* *** Decompression *** */
size_t ZBUFF_decompressContinue(ZBUFF_DCtx* zbd,
void* dst, size_t* dstCapacityPtr,
const void* src, size_t* srcSizePtr)
{
const char* const istart = (const char*)src;
const char* const iend = istart + *srcSizePtr;
const char* ip = istart;
char* const ostart = (char*)dst;
char* const oend = ostart + *dstCapacityPtr;
char* op = ostart;
U32 someMoreWork = 1;
while (someMoreWork) {
switch(zbd->stage)
{
case ZBUFFds_init :
return ERROR(init_missing);
case ZBUFFds_loadHeader :
{ size_t const hSize = ZSTD_getFrameParams(&(zbd->fParams), zbd->headerBuffer, zbd->lhSize);
if (ZSTD_isError(hSize)) return hSize;
if (hSize != 0) { /* need more input */
size_t const toLoad = hSize - zbd->lhSize; /* if hSize!=0, hSize > zbd->lhSize */
if (toLoad > (size_t)(iend-ip)) { /* not enough input to load full header */
memcpy(zbd->headerBuffer + zbd->lhSize, ip, iend-ip);
zbd->lhSize += iend-ip;
*dstCapacityPtr = 0;
return (hSize - zbd->lhSize) + ZSTD_blockHeaderSize; /* remaining header bytes + next block header */
}
memcpy(zbd->headerBuffer + zbd->lhSize, ip, toLoad); zbd->lhSize = hSize; ip += toLoad;
break;
} }
/* Consume header */
{ size_t const h1Size = ZSTD_nextSrcSizeToDecompress(zbd->zd); /* == ZSTD_frameHeaderSize_min */
size_t const h1Result = ZSTD_decompressContinue(zbd->zd, NULL, 0, zbd->headerBuffer, h1Size);
if (ZSTD_isError(h1Result)) return h1Result; /* should not happen : already checked */
if (h1Size < zbd->lhSize) { /* long header */
size_t const h2Size = ZSTD_nextSrcSizeToDecompress(zbd->zd);
size_t const h2Result = ZSTD_decompressContinue(zbd->zd, NULL, 0, zbd->headerBuffer+h1Size, h2Size);
if (ZSTD_isError(h2Result)) return h2Result;
} }
zbd->fParams.windowSize = MAX(zbd->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN);
/* Frame header instruct buffer sizes */
{ size_t const blockSize = MIN(zbd->fParams.windowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
size_t const neededOutSize = zbd->fParams.windowSize + blockSize;
zbd->blockSize = blockSize;
if (zbd->inBuffSize < blockSize) {
zbd->customMem.customFree(zbd->customMem.opaque, zbd->inBuff);
zbd->inBuffSize = blockSize;
zbd->inBuff = (char*)zbd->customMem.customAlloc(zbd->customMem.opaque, blockSize);
if (zbd->inBuff == NULL) return ERROR(memory_allocation);
}
if (zbd->outBuffSize < neededOutSize) {
zbd->customMem.customFree(zbd->customMem.opaque, zbd->outBuff);
zbd->outBuffSize = neededOutSize;
zbd->outBuff = (char*)zbd->customMem.customAlloc(zbd->customMem.opaque, neededOutSize);
if (zbd->outBuff == NULL) return ERROR(memory_allocation);
} }
zbd->stage = ZBUFFds_read;
/* pass-through */
case ZBUFFds_read:
{ size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zbd->zd);
if (neededInSize==0) { /* end of frame */
zbd->stage = ZBUFFds_init;
someMoreWork = 0;
break;
}
if ((size_t)(iend-ip) >= neededInSize) { /* decode directly from src */
const int isSkipFrame = ZSTD_isSkipFrame(zbd->zd);
size_t const decodedSize = ZSTD_decompressContinue(zbd->zd,
zbd->outBuff + zbd->outStart, (isSkipFrame ? 0 : zbd->outBuffSize - zbd->outStart),
ip, neededInSize);
if (ZSTD_isError(decodedSize)) return decodedSize;
ip += neededInSize;
if (!decodedSize && !isSkipFrame) break; /* this was just a header */
zbd->outEnd = zbd->outStart + decodedSize;
zbd->stage = ZBUFFds_flush;
break;
}
if (ip==iend) { someMoreWork = 0; break; } /* no more input */
zbd->stage = ZBUFFds_load;
/* pass-through */
}
case ZBUFFds_load:
{ size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zbd->zd);
size_t const toLoad = neededInSize - zbd->inPos; /* should always be <= remaining space within inBuff */
size_t loadedSize;
if (toLoad > zbd->inBuffSize - zbd->inPos) return ERROR(corruption_detected); /* should never happen */
loadedSize = ZBUFF_limitCopy(zbd->inBuff + zbd->inPos, toLoad, ip, iend-ip);
ip += loadedSize;
zbd->inPos += loadedSize;
if (loadedSize < toLoad) { someMoreWork = 0; break; } /* not enough input, wait for more */
/* decode loaded input */
{ const int isSkipFrame = ZSTD_isSkipFrame(zbd->zd);
size_t const decodedSize = ZSTD_decompressContinue(zbd->zd,
zbd->outBuff + zbd->outStart, zbd->outBuffSize - zbd->outStart,
zbd->inBuff, neededInSize);
if (ZSTD_isError(decodedSize)) return decodedSize;
zbd->inPos = 0; /* input is consumed */
if (!decodedSize && !isSkipFrame) { zbd->stage = ZBUFFds_read; break; } /* this was just a header */
zbd->outEnd = zbd->outStart + decodedSize;
zbd->stage = ZBUFFds_flush;
/* pass-through */
} }
case ZBUFFds_flush:
{ size_t const toFlushSize = zbd->outEnd - zbd->outStart;
size_t const flushedSize = ZBUFF_limitCopy(op, oend-op, zbd->outBuff + zbd->outStart, toFlushSize);
op += flushedSize;
zbd->outStart += flushedSize;
if (flushedSize == toFlushSize) { /* flush completed */
zbd->stage = ZBUFFds_read;
if (zbd->outStart + zbd->blockSize > zbd->outBuffSize)
zbd->outStart = zbd->outEnd = 0;
break;
}
/* cannot flush everything */
someMoreWork = 0;
break;
}
default: return ERROR(GENERIC); /* impossible */
} }
/* result */
*srcSizePtr = ip-istart;
*dstCapacityPtr = op-ostart;
{ size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zbd->zd);
if (!nextSrcSizeHint) return (zbd->outEnd != zbd->outStart); /* return 0 only if fully flushed too */
nextSrcSizeHint += ZSTD_blockHeaderSize * (ZSTD_nextInputType(zbd->zd) == ZSTDnit_block);
if (zbd->inPos > nextSrcSizeHint) return ERROR(GENERIC); /* should never happen */
nextSrcSizeHint -= zbd->inPos; /* already loaded*/
return nextSrcSizeHint;
}
}
/* *************************************
* Tool functions
***************************************/
size_t ZBUFF_recommendedDInSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX + ZSTD_blockHeaderSize /* block header size*/ ; }
size_t ZBUFF_recommendedDOutSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX; }