glibc/stdlib/mblen.c

64 lines
1.9 KiB
C

/* Copyright (C) 1991, 1997, 1998 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <stdlib.h>
#include <wchar.h>
#include <gconv.h>
#include <wcsmbs/wcsmbsload.h>
/* Return the length of the multibyte character (if there is one)
at S which is no longer than N characters.
The ISO C standard says that the `mblen' function must not change
the global state. */
int
mblen (const char *s, size_t n)
{
mbstate_t state;
int result;
/* If S is NULL the function has to return null or not null
depending on the encoding having a state depending encoding or
not. */
if (s == NULL)
{
/* Make sure we use the correct value. */
update_conversion_ptrs ();
result = __wcsmbs_gconv_fcts.towc->stateful;
}
else if (*s == '\0')
/* According to the ISO C 89 standard this is the expected behaviour.
Idiotic, but true. */
result = 0;
else
{
state.count = 0;
state.value = 0;
result = __mbrtowc (NULL, s, n, &state);
/* The `mbrtowc' functions tell us more than we need. Fold the -1
and -2 result into -1. */
if (result < 0)
result = -1;
}
return result;
}