| 9e052883 |
1 | /* LzHash.h -- HASH functions for LZ algorithms\r |
| 2 | 2019-10-30 : Igor Pavlov : Public domain */\r |
| 3 | \r |
| 4 | #ifndef __LZ_HASH_H\r |
| 5 | #define __LZ_HASH_H\r |
| 6 | \r |
| 7 | /*\r |
| 8 | (kHash2Size >= (1 << 8)) : Required\r |
| 9 | (kHash3Size >= (1 << 16)) : Required\r |
| 10 | */\r |
| 11 | \r |
| 12 | #define kHash2Size (1 << 10)\r |
| 13 | #define kHash3Size (1 << 16)\r |
| 14 | // #define kHash4Size (1 << 20)\r |
| 15 | \r |
| 16 | #define kFix3HashSize (kHash2Size)\r |
| 17 | #define kFix4HashSize (kHash2Size + kHash3Size)\r |
| 18 | // #define kFix5HashSize (kHash2Size + kHash3Size + kHash4Size)\r |
| 19 | \r |
| 20 | /*\r |
| 21 | We use up to 3 crc values for hash:\r |
| 22 | crc0\r |
| 23 | crc1 << Shift_1\r |
| 24 | crc2 << Shift_2\r |
| 25 | (Shift_1 = 5) and (Shift_2 = 10) is good tradeoff.\r |
| 26 | Small values for Shift are not good for collision rate.\r |
| 27 | Big value for Shift_2 increases the minimum size\r |
| 28 | of hash table, that will be slow for small files.\r |
| 29 | */\r |
| 30 | \r |
| 31 | #define kLzHash_CrcShift_1 5\r |
| 32 | #define kLzHash_CrcShift_2 10\r |
| 33 | \r |
| 34 | #endif\r |
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