ddidderr/zstd-rs
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This commit is contained in:
Yann Collet
2016-01-25 04:10:46 +01:00
parent 59d1f79768
commit afe0709964
4 changed files with 99 additions and 16 deletions
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lib/huff0.c
+71 -3
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@@ -473,10 +473,76 @@ static size_t HUF_compress_into4Segments(void* dst, size_t dstSize, const void*
}
static size_t HUF_compress_internal (
void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog,
unsigned singleStream)
{
BYTE* const ostart = (BYTE*)dst;
BYTE* op = ostart;
BYTE* const oend = ostart + dstSize;
U32 count[HUF_MAX_SYMBOL_VALUE+1];
HUF_CElt CTable[HUF_MAX_SYMBOL_VALUE+1];
size_t errorCode;
/* checks & inits */
if (srcSize < 2) return 0; /* Uncompressed */
if (dstSize < 1) return 0; /* not compressible within dst budget */
if (srcSize > 128 * 1024) return ERROR(srcSize_wrong); /* current block size limit */
if (huffLog > HUF_MAX_TABLELOG) return ERROR(tableLog_tooLarge);
if (!maxSymbolValue) maxSymbolValue = HUF_MAX_SYMBOL_VALUE;
if (!huffLog) huffLog = HUF_DEFAULT_TABLELOG;
/* Scan input and build symbol stats */
errorCode = FSE_count (count, &maxSymbolValue, (const BYTE*)src, srcSize);
if (HUF_isError(errorCode)) return errorCode;
if (errorCode == srcSize) { *ostart = ((const BYTE*)src)[0]; return 1; }
if (errorCode <= (srcSize >> 7)+1) return 0; /* Heuristic : not compressible enough */
/* Build Huffman Tree */
errorCode = HUF_buildCTable (CTable, count, maxSymbolValue, huffLog);
if (HUF_isError(errorCode)) return errorCode;
huffLog = (U32)errorCode;
/* Write table description header */
errorCode = HUF_writeCTable (op, dstSize, CTable, maxSymbolValue, huffLog);
if (HUF_isError(errorCode)) return errorCode;
if (errorCode + 12 >= srcSize) return 0; /* not useful to try compression */
op += errorCode;
/* Compress */
if (singleStream)
errorCode = HUF_compress_usingCTable(op, oend - op, src, srcSize, CTable); /* single segment */
else
errorCode = HUF_compress_into4Segments(op, oend - op, src, srcSize, CTable);
if (HUF_isError(errorCode)) return errorCode;
if (errorCode==0) return 0;
op += errorCode;
/* check compressibility */
if ((size_t)(op-ostart) >= srcSize-1)
return 0;
return op-ostart;
}
size_t HUF_compress1X (void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog)
{
return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 1);
}
size_t HUF_compress2 (void* dst, size_t dstSize,
const void* src, size_t srcSize,
unsigned maxSymbolValue, unsigned huffLog)
{
#if 1
return HUF_compress_internal(dst, dstSize, src, srcSize, maxSymbolValue, huffLog, 0);
#else
BYTE* const ostart = (BYTE*)dst;
BYTE* op = ostart;
BYTE* const oend = ostart + dstSize;
@@ -522,8 +588,10 @@ size_t HUF_compress2 (void* dst, size_t dstSize,
return 0;
return op-ostart;
#endif
}
size_t HUF_compress (void* dst, size_t maxDstSize, const void* src, size_t srcSize)
{
return HUF_compress2(dst, maxDstSize, src, (U32)srcSize, 255, HUF_DEFAULT_TABLELOG);
@@ -620,9 +688,9 @@ static size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
}
/* ************************/
/* single-symbol decoding */
/* ************************/
/*-***************************/
/* single-symbol decoding */
/*-***************************/
size_t HUF_readDTableX2 (U16* DTable, const void* src, size_t srcSize)
{