1/* xstrchr.c - strchr(3) that handles multibyte characters. */
2
3/* Copyright (C) 2002 Free Software Foundation, Inc.
4
5   This file is part of GNU Bash, the Bourne Again SHell.
6
7   Bash is free software: you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation, either version 3 of the License, or
10   (at your option) any later version.
11
12   Bash is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with Bash.  If not, see <http://www.gnu.org/licenses/>.
19*/
20
21#include <config.h>
22
23#ifdef HAVE_STDLIB_H
24#  include <stdlib.h>
25#endif
26
27#include "bashansi.h"
28#include "shmbutil.h"
29
30#undef xstrchr
31
32/* In some locales, the non-first byte of some multibyte characters have
33   the same value as some ascii character.  Faced with these strings, a
34   legacy strchr() might return the wrong value. */
35
36char *
37#if defined (PROTOTYPES)
38xstrchr (const char *s, int c)
39#else
40xstrchr (s, c)
41     const char *s;
42     int c;
43#endif
44{
45#if HANDLE_MULTIBYTE
46  char *pos;
47  mbstate_t state;
48  size_t strlength, mblength;
49
50  /* The locale encodings with said weird property are BIG5, BIG5-HKSCS,
51     GBK, GB18030, SHIFT_JIS, and JOHAB.  They exhibit the problem only
52     when c >= 0x30.  We can therefore use the faster bytewise search if
53     c <= 0x30. */
54  if ((unsigned char)c >= '0' && MB_CUR_MAX > 1)
55    {
56      pos = (char *)s;
57      memset (&state, '\0', sizeof(mbstate_t));
58      strlength = strlen (s);
59
60      while (strlength > 0)
61	{
62	  mblength = mbrlen (pos, strlength, &state);
63	  if (mblength == (size_t)-2 || mblength == (size_t)-1 || mblength == (size_t)0)
64	    mblength = 1;
65
66	  if (c == (unsigned char)*pos)
67	    return pos;
68
69	  strlength -= mblength;
70	  pos += mblength;
71	}
72
73      return ((char *)NULL);
74    }
75  else
76#endif
77  return (strchr (s, c));
78}
79