glibc/stdlib/wcstombs.c
1995-02-18 01:27:10 +00:00

78 lines
2.1 KiB
C

/* Copyright (C) 1991, 1992 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., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <localeinfo.h>
#include <ctype.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* Convert the `wchar_t' string in PWCS to a multibyte character string
in S, writing no more than N characters. Return the number of bytes
written, or (size_t) -1 if an invalid `wchar_t' was found. */
size_t
DEFUN(wcstombs, (s, pwcs, n),
register char *s AND register CONST wchar_t *pwcs AND register size_t n)
{
register CONST mb_char *mb;
register int shift = 0;
register size_t written = 0;
register wchar_t w;
while ((w = *pwcs++) != (wchar_t) '\0')
{
if (isascii (w))
{
/* A normal character. */
*s++ = (unsigned char) w;
--n;
++written;
}
else
{
mb = &_ctype_info->mbchar->mb_chars[w + shift];
if (mb->string == NULL || mb->len == 0)
{
written = (size_t) -1;
break;
}
else if (mb->len > n)
break;
else
{
memcpy ((PTR) s, (CONST PTR) mb->string, mb->len);
s += mb->len;
n -= mb->len;
written += mb->len;
shift += mb->shift;
}
}
}
/* Terminate the string if it has space. */
if (n > 0)
*s = '\0';
/* Return the number of characters written (or maybe an error). */
return written;
}