1/* Copyright (C) 1991-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <string.h>
19#include <stdint.h>
20#include <libc-pointer-arith.h>
21
22#undef strcspn
23
24#ifndef STRCSPN
25# define STRCSPN strcspn
26#endif
27
28/* Return the length of the maximum initial segment of S
29 which contains no characters from REJECT. */
30size_t
31STRCSPN (const char *str, const char *reject)
32{
33 if (__glibc_unlikely (reject[0] == '\0')
34 || __glibc_unlikely (reject[1] == '\0'))
35 return __strchrnul (str, reject [0]) - str;
36
37 /* Use multiple small memsets to enable inlining on most targets. */
38 unsigned char table[256];
39 unsigned char *p = memset (table, 0, 64);
40 memset (p + 64, 0, 64);
41 memset (p + 128, 0, 64);
42 memset (p + 192, 0, 64);
43
44 unsigned char *s = (unsigned char*) reject;
45 unsigned char tmp;
46 do
47 p[tmp = *s++] = 1;
48 while (tmp);
49
50 s = (unsigned char*) str;
51 if (p[s[0]]) return 0;
52 if (p[s[1]]) return 1;
53 if (p[s[2]]) return 2;
54 if (p[s[3]]) return 3;
55
56 s = (unsigned char *) PTR_ALIGN_DOWN (s, 4);
57
58 unsigned int c0, c1, c2, c3;
59 do
60 {
61 s += 4;
62 c0 = p[s[0]];
63 c1 = p[s[1]];
64 c2 = p[s[2]];
65 c3 = p[s[3]];
66 }
67 while ((c0 | c1 | c2 | c3) == 0);
68
69 size_t count = s - (unsigned char *) str;
70 return (c0 | c1) != 0 ? count - c0 + 1 : count - c2 + 3;
71}
72libc_hidden_builtin_def (strcspn)
73