1///////////////////////////////////////////////////////////////////////////////
2//
3/// \file       lz_encoder_hash.h
4/// \brief      Hash macros for match finders
5//
6//  Author:     Igor Pavlov
7//
8//  This file has been put into the public domain.
9//  You can do whatever you want with this file.
10//
11///////////////////////////////////////////////////////////////////////////////
12
13#ifndef LZMA_LZ_ENCODER_HASH_H
14#define LZMA_LZ_ENCODER_HASH_H
15
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
22#else
23#	include "check.h"
24#	define hash_table lzma_crc32_table[0]
25#endif
26
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)
30
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)
34
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)
38
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 = read16ne(cur)
43#else
44#	define hash_2_calc() \
45		const uint32_t hash_value \
46			= (uint32_t)(cur[0]) | ((uint32_t)(cur[1]) << 8)
47#endif
48
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
54
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
62
63
64// The following are not currently used.
65
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)) \
75				& mf->hash_mask; \
76	hash_4_value &= HASH_4_MASK
77
78/*
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
83*/
84
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
89
90#define mt_hash_2_calc() \
91	const uint32_t hash_2_value \
92			= (hash_table[cur[0]] ^ cur[1]) & HASH_2_MASK
93
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
99
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
107
108#endif
109