1 ///////////////////////////////////////////////////////////////////////////////
3 /// \file lz_encoder_hash.h
4 /// \brief Hash macros for match finders
8 // This file has been put into the public domain.
9 // You can do whatever you want with this file.
11 ///////////////////////////////////////////////////////////////////////////////
13 #ifndef LZMA_LZ_ENCODER_HASH_H
14 #define LZMA_LZ_ENCODER_HASH_H
16 #if defined(WORDS_BIGENDIAN) && !defined(HAVE_SMALL)
17 // This is to make liblzma produce the same output on big endian
18 // systems that it does on little endian systems. lz_encoder.c
19 // takes care of including the actual table.
20 extern const uint32_t lzma_lz_hash_table[256];
21 # define hash_table lzma_lz_hash_table
24 # define hash_table lzma_crc32_table[0]
27 #define HASH_2_SIZE (UINT32_C(1) << 10)
28 #define HASH_3_SIZE (UINT32_C(1) << 16)
29 #define HASH_4_SIZE (UINT32_C(1) << 20)
31 #define HASH_2_MASK (HASH_2_SIZE - 1)
32 #define HASH_3_MASK (HASH_3_SIZE - 1)
33 #define HASH_4_MASK (HASH_4_SIZE - 1)
35 #define FIX_3_HASH_SIZE (HASH_2_SIZE)
36 #define FIX_4_HASH_SIZE (HASH_2_SIZE + HASH_3_SIZE)
37 #define FIX_5_HASH_SIZE (HASH_2_SIZE + HASH_3_SIZE + HASH_4_SIZE)
39 // Endianness doesn't matter in hash_2_calc() (no effect on the output).
40 #ifdef TUKLIB_FAST_UNALIGNED_ACCESS
41 # define hash_2_calc() \
42 const uint32_t hash_value = *(const uint16_t *)(cur)
44 # define hash_2_calc() \
45 const uint32_t hash_value \
46 = (uint32_t)(cur[0]) | ((uint32_t)(cur[1]) << 8)
49 #define hash_3_calc() \
50 const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \
51 const uint32_t hash_2_value = temp & HASH_2_MASK; \
52 const uint32_t hash_value \
53 = (temp ^ ((uint32_t)(cur[2]) << 8)) & mf->hash_mask
55 #define hash_4_calc() \
56 const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \
57 const uint32_t hash_2_value = temp & HASH_2_MASK; \
58 const uint32_t hash_3_value \
59 = (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK; \
60 const uint32_t hash_value = (temp ^ ((uint32_t)(cur[2]) << 8) \
61 ^ (hash_table[cur[3]] << 5)) & mf->hash_mask
64 // The following are not currently used.
66 #define hash_5_calc() \
67 const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \
68 const uint32_t hash_2_value = temp & HASH_2_MASK; \
69 const uint32_t hash_3_value \
70 = (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK; \
71 uint32_t hash_4_value = (temp ^ ((uint32_t)(cur[2]) << 8) ^ \
72 ^ hash_table[cur[3]] << 5); \
73 const uint32_t hash_value \
74 = (hash_4_value ^ (hash_table[cur[4]] << 3)) \
76 hash_4_value &= HASH_4_MASK
79 #define hash_zip_calc() \
80 const uint32_t hash_value \
81 = (((uint32_t)(cur[0]) | ((uint32_t)(cur[1]) << 8)) \
82 ^ hash_table[cur[2]]) & 0xFFFF
85 #define hash_zip_calc() \
86 const uint32_t hash_value \
87 = (((uint32_t)(cur[2]) | ((uint32_t)(cur[0]) << 8)) \
88 ^ hash_table[cur[1]]) & 0xFFFF
90 #define mt_hash_2_calc() \
91 const uint32_t hash_2_value \
92 = (hash_table[cur[0]] ^ cur[1]) & HASH_2_MASK
94 #define mt_hash_3_calc() \
95 const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \
96 const uint32_t hash_2_value = temp & HASH_2_MASK; \
97 const uint32_t hash_3_value \
98 = (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK
100 #define mt_hash_4_calc() \
101 const uint32_t temp = hash_table[cur[0]] ^ cur[1]; \
102 const uint32_t hash_2_value = temp & HASH_2_MASK; \
103 const uint32_t hash_3_value \
104 = (temp ^ ((uint32_t)(cur[2]) << 8)) & HASH_3_MASK; \
105 const uint32_t hash_4_value = (temp ^ ((uint32_t)(cur[2]) << 8) ^ \
106 (hash_table[cur[3]] << 5)) & HASH_4_MASK