1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
/* compare256_p.h -- 256 byte memory comparison with match length return
* Copyright (C) 2020 Nathan Moinvaziri
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#include "zmemory.h"
#include "deflate.h"
#include "fallback_builtins.h"
/* 8-bit integer comparison */
static inline uint32_t compare256_8(const uint8_t *src0, const uint8_t *src1) {
uint32_t len = 0;
do {
if (*src0 != *src1)
return len;
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len;
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len;
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len;
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len;
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len;
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len;
src0 += 1, src1 += 1, len += 1;
if (*src0 != *src1)
return len;
src0 += 1, src1 += 1, len += 1;
} while (len < 256);
return 256;
}
/* 16-bit integer comparison */
static inline uint32_t compare256_16(const uint8_t *src0, const uint8_t *src1) {
uint32_t len = 0;
do {
if (zng_memcmp_2(src0, src1) != 0)
return len + (*src0 == *src1);
src0 += 2, src1 += 2, len += 2;
if (zng_memcmp_2(src0, src1) != 0)
return len + (*src0 == *src1);
src0 += 2, src1 += 2, len += 2;
if (zng_memcmp_2(src0, src1) != 0)
return len + (*src0 == *src1);
src0 += 2, src1 += 2, len += 2;
if (zng_memcmp_2(src0, src1) != 0)
return len + (*src0 == *src1);
src0 += 2, src1 += 2, len += 2;
} while (len < 256);
return 256;
}
#ifdef HAVE_BUILTIN_CTZ
/* 32-bit integer comparison */
static inline uint32_t compare256_32(const uint8_t *src0, const uint8_t *src1) {
uint32_t len = 0;
do {
uint32_t sv, mv, diff;
sv = zng_memread_4(src0);
mv = zng_memread_4(src1);
diff = sv ^ mv;
if (diff) {
# if BYTE_ORDER == LITTLE_ENDIAN
uint32_t match_byte = __builtin_ctz(diff) / 8;
# else
uint32_t match_byte = __builtin_clz(diff) / 8;
# endif
return len + match_byte;
}
src0 += 4, src1 += 4, len += 4;
} while (len < 256);
return 256;
}
#endif
#ifdef HAVE_BUILTIN_CTZLL
/* 64-bit integer comparison */
static inline uint32_t compare256_64(const uint8_t *src0, const uint8_t *src1) {
uint32_t len = 0;
do {
uint64_t sv, mv, diff;
sv = zng_memread_8(src0);
mv = zng_memread_8(src1);
diff = sv ^ mv;
if (diff) {
# if BYTE_ORDER == LITTLE_ENDIAN
uint64_t match_byte = __builtin_ctzll(diff) / 8;
# else
uint64_t match_byte = __builtin_clzll(diff) / 8;
# endif
return len + (uint32_t)match_byte;
}
src0 += 8, src1 += 8, len += 8;
} while (len < 256);
return 256;
}
#endif
|
