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Diffstat (limited to 'src/Common/lzma/LzHash.h')
| -rw-r--r-- | src/Common/lzma/LzHash.h | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/Common/lzma/LzHash.h b/src/Common/lzma/LzHash.h new file mode 100644 index 00000000..2b6290b6 --- /dev/null +++ b/src/Common/lzma/LzHash.h @@ -0,0 +1,34 @@ +/* LzHash.h -- HASH constants for LZ algorithms +2023-03-05 : Igor Pavlov : Public domain */ + +#ifndef ZIP7_INC_LZ_HASH_H +#define ZIP7_INC_LZ_HASH_H + +/* + (kHash2Size >= (1 << 8)) : Required + (kHash3Size >= (1 << 16)) : Required +*/ + +#define kHash2Size (1 << 10) +#define kHash3Size (1 << 16) +// #define kHash4Size (1 << 20) + +#define kFix3HashSize (kHash2Size) +#define kFix4HashSize (kHash2Size + kHash3Size) +// #define kFix5HashSize (kHash2Size + kHash3Size + kHash4Size) + +/* + We use up to 3 crc values for hash: + crc0 + crc1 << Shift_1 + crc2 << Shift_2 + (Shift_1 = 5) and (Shift_2 = 10) is good tradeoff. + Small values for Shift are not good for collision rate. + Big value for Shift_2 increases the minimum size + of hash table, that will be slow for small files. +*/ + +#define kLzHash_CrcShift_1 5 +#define kLzHash_CrcShift_2 10 + +#endif |