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minor refactoring

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This commit is contained in:
Yann Collet 2016-03-15 01:33:36 +01:00
parent d1b26849e5
commit 1c2c2bcaff
2 changed files with 21 additions and 21 deletions
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9
lib/zstd_compress.c
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@ -2205,19 +2205,20 @@ size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* zc,
/* Write Frame Header into ctx headerBuffer */ /* Write Frame Header into ctx headerBuffer */
MEM_writeLE32(zc->headerBuffer, ZSTD_MAGICNUMBER); MEM_writeLE32(zc->headerBuffer, ZSTD_MAGICNUMBER);
{ {
BYTE* const op = (BYTE*)zc->headerBuffer;
U32 const fcsSize[4] = { 0, 1, 2, 8 }; U32 const fcsSize[4] = { 0, 1, 2, 8 };
U32 const fcsId = (params.srcSize>0) + (params.srcSize>=256) + (params.srcSize>=65536+256); /* 0-3 */ U32 const fcsId = (params.srcSize>0) + (params.srcSize>=256) + (params.srcSize>=65536+256); /* 0-3 */
BYTE fdescriptor = (BYTE)(params.windowLog - ZSTD_WINDOWLOG_ABSOLUTEMIN); /* windowLog : 4 KB - 128 MB */ BYTE fdescriptor = (BYTE)(params.windowLog - ZSTD_WINDOWLOG_ABSOLUTEMIN); /* windowLog : 4 KB - 128 MB */
fdescriptor |= (BYTE)((params.searchLength==3)<<4); /* mml : 3-4 */ fdescriptor |= (BYTE)((params.searchLength==3)<<4); /* mml : 3-4 */
fdescriptor |= (BYTE)(fcsId << 6); fdescriptor |= (BYTE)(fcsId << 6);
((BYTE*)zc->headerBuffer)[4] = fdescriptor; op[4] = fdescriptor;
switch(fcsId) switch(fcsId)
{ {
default: /* impossible */ default: /* impossible */
case 0 : break; case 0 : break;
case 1 : ((BYTE*)zc->headerBuffer)[5] = (BYTE)(params.srcSize); break; case 1 : op[5] = (BYTE)(params.srcSize); break;
case 2 : MEM_writeLE16(((BYTE*)zc->headerBuffer)+5, (U16)(params.srcSize-256)); break; case 2 : MEM_writeLE16(op+5, (U16)(params.srcSize-256)); break;
case 3 : MEM_writeLE64(((BYTE*)zc->headerBuffer)+5, (U64)(params.srcSize)); break; case 3 : MEM_writeLE64(op+5, (U64)(params.srcSize)); break;
} }
zc->hbSize = ZSTD_frameHeaderSize_min + fcsSize[fcsId]; zc->hbSize = ZSTD_frameHeaderSize_min + fcsSize[fcsId];
} }

13
lib/zstd_decompress.c
View File

@ -303,21 +303,21 @@ static size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize)
/** ZSTD_getFrameParams() : /** ZSTD_getFrameParams() :
* decode Frame Header, or provide expected `srcSize`. * decode Frame Header, or provide expected `srcSize`.
* @return : 0, `fparamsPtr` is correctly filled, * @return : 0, `fparamsPtr` is correctly filled,
* >0, not enough srcSize, provide expected `srcSize`, * >0, `srcSize` is too small, result is expected `srcSize`,
* or an error code, which can be tested using ZSTD_isError() */ * or an error code, which can be tested using ZSTD_isError() */
size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t srcSize) size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t const srcSize)
{ {
const BYTE* ip = (const BYTE*)src; const BYTE* ip = (const BYTE*)src;
BYTE frameDesc;
if (srcSize < ZSTD_frameHeaderSize_min) return ZSTD_frameHeaderSize_min; if (srcSize < ZSTD_frameHeaderSize_min) return ZSTD_frameHeaderSize_min;
if (MEM_readLE32(src) != ZSTD_MAGICNUMBER) return ERROR(prefix_unknown); if (MEM_readLE32(src) != ZSTD_MAGICNUMBER) return ERROR(prefix_unknown);
/* ensure there is enough `srcSize` to fully read/decode frame header */
{ size_t const fhsize = ZSTD_frameHeaderSize(src, srcSize); { size_t const fhsize = ZSTD_frameHeaderSize(src, srcSize);
if (srcSize < fhsize) return fhsize; } if (srcSize < fhsize) return fhsize; }
memset(fparamsPtr, 0, sizeof(*fparamsPtr)); memset(fparamsPtr, 0, sizeof(*fparamsPtr));
frameDesc = ip[4]; { BYTE const frameDesc = ip[4];
fparamsPtr->windowLog = (frameDesc & 0xF) + ZSTD_WINDOWLOG_ABSOLUTEMIN; fparamsPtr->windowLog = (frameDesc & 0xF) + ZSTD_WINDOWLOG_ABSOLUTEMIN;
fparamsPtr->mml = (frameDesc & 0x10) ? MINMATCH-1 : MINMATCH; fparamsPtr->mml = (frameDesc & 0x10) ? MINMATCH-1 : MINMATCH;
if ((frameDesc & 0x20) != 0) return ERROR(frameParameter_unsupported); /* reserved 1 bit */ if ((frameDesc & 0x20) != 0) return ERROR(frameParameter_unsupported); /* reserved 1 bit */
@ -328,14 +328,13 @@ size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t
case 1 : fparamsPtr->frameContentSize = ip[5]; break; case 1 : fparamsPtr->frameContentSize = ip[5]; break;
case 2 : fparamsPtr->frameContentSize = MEM_readLE16(ip+5)+256; break; case 2 : fparamsPtr->frameContentSize = MEM_readLE16(ip+5)+256; break;
case 3 : fparamsPtr->frameContentSize = MEM_readLE64(ip+5); break; case 3 : fparamsPtr->frameContentSize = MEM_readLE64(ip+5); break;
} } }
return 0; return 0;
} }
/** ZSTD_decodeFrameHeader() : /** ZSTD_decodeFrameHeader() :
* decode Frame Header. * `srcSize` must be the size provided by ZSTD_frameHeaderSize().
* srcSize must be the size provided by ZSTD_decodeFrameHeader_Part1().
* @return : 0, or an error code, which can be tested using ZSTD_isError() */ * @return : 0, or an error code, which can be tested using ZSTD_isError() */
static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx* zc, const void* src, size_t srcSize) static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx* zc, const void* src, size_t srcSize)
{ {