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
|
/* Copyright (C) 1991-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <string.h>
#include <stdint.h>
#include <libc-pointer-arith.h>
#undef strspn
#ifndef STRSPN
# define STRSPN strspn
#endif
/* Return the length of the maximum initial segment
of S which contains only characters in ACCEPT. */
size_t
STRSPN (const char *str, const char *accept)
{
if (accept[0] == '\0')
return 0;
if (__glibc_unlikely (accept[1] == '\0'))
{
const char *a = str;
for (; *str == *accept; str++);
return str - a;
}
/* Use multiple small memsets to enable inlining on most targets. */
unsigned char table[256];
unsigned char *p = memset (table, 0, 64);
memset (p + 64, 0, 64);
memset (p + 128, 0, 64);
memset (p + 192, 0, 64);
unsigned char *s = (unsigned char*) accept;
/* Different from strcspn it does not add the NULL on the table
so can avoid check if str[i] is NULL, since table['\0'] will
be 0 and thus stopping the loop check. */
do
p[*s++] = 1;
while (*s);
s = (unsigned char*) str;
if (!p[s[0]]) return 0;
if (!p[s[1]]) return 1;
if (!p[s[2]]) return 2;
if (!p[s[3]]) return 3;
s = (unsigned char *) PTR_ALIGN_DOWN (s, 4);
unsigned int c0, c1, c2, c3;
do {
s += 4;
c0 = p[s[0]];
c1 = p[s[1]];
c2 = p[s[2]];
c3 = p[s[3]];
} while ((c0 & c1 & c2 & c3) != 0);
size_t count = s - (unsigned char *) str;
return (c0 & c1) == 0 ? count + c0 : count + c2 + 2;
}
libc_hidden_builtin_def (strspn)
|
GitWeb
