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Igor Pavlov
2021-07-22 23:00:14 +01:00
committed by Kornel
parent 4a960640a3
commit 585698650f
619 changed files with 34904 additions and 10859 deletions
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63
C/LzHash.h
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@@ -1,57 +1,34 @@
/* LzHash.h -- HASH functions for LZ algorithms
2015-04-12 : Igor Pavlov : Public domain */
2019-10-30 : Igor Pavlov : Public domain */
#ifndef __LZ_HASH_H
#define __LZ_HASH_H
/*
(kHash2Size >= (1 << 8)) : Required
(kHash3Size >= (1 << 16)) : Required
*/
#define kHash2Size (1 << 10)
#define kHash3Size (1 << 16)
#define kHash4Size (1 << 20)
// #define kHash4Size (1 << 20)
#define kFix3HashSize (kHash2Size)
#define kFix4HashSize (kHash2Size + kHash3Size)
#define kFix5HashSize (kHash2Size + kHash3Size + kHash4Size)
// #define kFix5HashSize (kHash2Size + kHash3Size + kHash4Size)
#define HASH2_CALC hv = cur[0] | ((UInt32)cur[1] << 8);
/*
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 HASH3_CALC { \
UInt32 temp = p->crc[cur[0]] ^ cur[1]; \
h2 = temp & (kHash2Size - 1); \
hv = (temp ^ ((UInt32)cur[2] << 8)) & p->hashMask; }
#define HASH4_CALC { \
UInt32 temp = p->crc[cur[0]] ^ cur[1]; \
h2 = temp & (kHash2Size - 1); \
temp ^= ((UInt32)cur[2] << 8); \
h3 = temp & (kHash3Size - 1); \
hv = (temp ^ (p->crc[cur[3]] << 5)) & p->hashMask; }
#define HASH5_CALC { \
UInt32 temp = p->crc[cur[0]] ^ cur[1]; \
h2 = temp & (kHash2Size - 1); \
temp ^= ((UInt32)cur[2] << 8); \
h3 = temp & (kHash3Size - 1); \
temp ^= (p->crc[cur[3]] << 5); \
h4 = temp & (kHash4Size - 1); \
hv = (temp ^ (p->crc[cur[4]] << 3)) & p->hashMask; }
/* #define HASH_ZIP_CALC hv = ((cur[0] | ((UInt32)cur[1] << 8)) ^ p->crc[cur[2]]) & 0xFFFF; */
#define HASH_ZIP_CALC hv = ((cur[2] | ((UInt32)cur[0] << 8)) ^ p->crc[cur[1]]) & 0xFFFF;
#define MT_HASH2_CALC \
h2 = (p->crc[cur[0]] ^ cur[1]) & (kHash2Size - 1);
#define MT_HASH3_CALC { \
UInt32 temp = p->crc[cur[0]] ^ cur[1]; \
h2 = temp & (kHash2Size - 1); \
h3 = (temp ^ ((UInt32)cur[2] << 8)) & (kHash3Size - 1); }
#define MT_HASH4_CALC { \
UInt32 temp = p->crc[cur[0]] ^ cur[1]; \
h2 = temp & (kHash2Size - 1); \
temp ^= ((UInt32)cur[2] << 8); \
h3 = temp & (kHash3Size - 1); \
h4 = (temp ^ (p->crc[cur[3]] << 5)) & (kHash4Size - 1); }
#define kLzHash_CrcShift_1 5
#define kLzHash_CrcShift_2 10
#endif