mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-22 21:10:07 +00:00
77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
/* 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)
|