zstd/compress/zstd_compress_literals.c

16 size_t ZSTD_noCompressLiterals (void* dst, size_t dstCapacity, const void* src, size_t srcSize)
19     U32   const flSize = 1 + (srcSize>31) + (srcSize>4095);
21     RETURN_ERROR_IF(srcSize + flSize > dstCapacity, dstSize_tooSmall, "");
26             ostart[0] = (BYTE)((U32)set_basic + (srcSize<<3));
29             MEM_writeLE16(ostart, (U16)((U32)set_basic + (1<<2) + (srcSize<<4)));
32             MEM_writeLE32(ostart, (U32)((U32)set_basic + (3<<2) + (srcSize<<4)));
38     ZSTD_memcpy(ostart + flSize, src, srcSize);
39     DEBUGLOG(5, "Raw literals: %u -> %u", (U32)srcSize, (U32)(srcSize + flSize));
40     return srcSize + flSize;
43 size_t ZSTD_compressRleLiteralsBlock (void* dst, size_t dstCapacity, const void* src, size_t srcSize)
46     U32   const flSize = 1 + (srcSize>31) + (srcSize>4095);
53             ostart[0] = (BYTE)((U32)set_rle + (srcSize<<3));
56             MEM_writeLE16(ostart, (U16)((U32)set_rle + (1<<2) + (srcSize<<4)));
59             MEM_writeLE32(ostart, (U32)((U32)set_rle + (3<<2) + (srcSize<<4)));
66     DEBUGLOG(5, "RLE literals: %u -> %u", (U32)srcSize, (U32)flSize + 1);
74                         const void* src, size_t srcSize,
79     size_t const minGain = ZSTD_minGain(srcSize, strategy);
80     size_t const lhSize = 3 + (srcSize >= 1 KB) + (srcSize >= 16 KB);
82     U32 singleStream = srcSize < 256;
86     DEBUGLOG(5,"ZSTD_compressLiterals (disableLiteralCompression=%i srcSize=%u)",
87                 disableLiteralCompression, (U32)srcSize);
93         return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
98         if (srcSize <= minLitSize) return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
103         int const preferRepeat = strategy < ZSTD_lazy ? srcSize <= 1024 : 0;
107                 ostart+lhSize, dstCapacity-lhSize, src, srcSize,
111                 ostart+lhSize, dstCapacity-lhSize, src, srcSize,
121     if ((cLitSize==0) || (cLitSize >= srcSize - minGain) || ERR_isError(cLitSize)) {
123         return ZSTD_noCompressLiterals(dst, dstCapacity, src, srcSize);
127         return ZSTD_compressRleLiteralsBlock(dst, dstCapacity, src, srcSize);
139         {   U32 const lhc = hType + ((!singleStream) << 2) + ((U32)srcSize<<4) + ((U32)cLitSize<<14);
144         {   U32 const lhc = hType + (2 << 2) + ((U32)srcSize<<4) + ((U32)cLitSize<<18);
149         {   U32 const lhc = hType + (3 << 2) + ((U32)srcSize<<4) + ((U32)cLitSize<<22);
157     DEBUGLOG(5, "Compressed literals: %u -> %u", (U32)srcSize, (U32)(lhSize+cLitSize));