rm_/lib/mbschr.c
2022-07-28 14:16:50 +08:00

53 lines
1.8 KiB
C

/* Searching a string for a character.
Copyright (C) 2007-2022 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2007.
This file 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 3 of the
License, or (at your option) any later version.
This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include <string.h>
#include "mbuiter.h"
/* Locate the first single-byte character C in the character string STRING,
and return a pointer to it. Return NULL if C is not found in STRING. */
char *
mbschr (const char *string, int c)
{
if (MB_CUR_MAX > 1
/* Optimization: We know that ASCII characters < 0x30 don't occur as
part of multibyte characters longer than 1 byte. Hence, if c < 0x30,
the faster unibyte loop can be used. */
&& (unsigned char) c >= 0x30)
{
mbui_iterator_t iter;
for (mbui_init (iter, string);; mbui_advance (iter))
{
if (!mbui_avail (iter))
goto notfound;
if (mb_len (mbui_cur (iter)) == 1
&& (unsigned char) * mbui_cur_ptr (iter) == (unsigned char) c)
break;
}
return (char *) mbui_cur_ptr (iter);
notfound:
return NULL;
}
else
return strchr (string, c);
}