Update.
[glibc.git] / stdlib / mblen.c
blob9d8d0ccc5a55a07dbef0d4a4b109eb81d30f01b3
1 /* Copyright (C) 1991, 1997, 1998 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
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 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
19 #include <stdlib.h>
20 #include <wchar.h>
21 #include <gconv.h>
22 #include <wcsmbs/wcsmbsload.h>
25 /* Return the length of the multibyte character (if there is one)
26 at S which is no longer than N characters.
27 The ISO C standard says that the `mblen' function must not change
28 the global state. */
29 int
30 mblen (const char *s, size_t n)
32 mbstate_t state;
33 int result;
35 /* If S is NULL the function has to return null or not null
36 depending on the encoding having a state depending encoding or
37 not. */
38 if (s == NULL)
40 /* Make sure we use the correct value. */
41 update_conversion_ptrs ();
43 result = __wcsmbs_gconv_fcts.towc->stateful;
45 else if (*s == '\0')
46 /* According to the ISO C 89 standard this is the expected behaviour.
47 Idiotic, but true. */
48 result = 0;
49 else
51 state.count = 0;
52 state.value = 0;
54 result = __mbrtowc (NULL, s, n, &state);
56 /* The `mbrtowc' functions tell us more than we need. Fold the -1
57 and -2 result into -1. */
58 if (result < 0)
59 result = -1;
62 return result;