glibc/stdlib/mbstowcs.c

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1995-02-18 01:27:10 +00:00
/* 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 <ctype.h>
#include <stddef.h>
#include <stdlib.h>
extern int _mb_shift; /* Defined in mbtowc.c. */
/* Convert the string of multibyte characters in S to `wchar_t's in
PWCS, writing no more than N. Return the number written,
or (size_t) -1 if an invalid multibyte character is encountered. */
size_t
DEFUN(mbstowcs, (pwcs, s, n),
register wchar_t *pwcs AND register CONST char *s AND register size_t n)
{
int save_shift;
register size_t written = 0;
/* Save the shift state. */
save_shift = _mb_shift;
/* Reset the shift state. */
_mb_shift = 0;
while (*s != '\0')
{
int len;
if (isascii (*s))
{
*pwcs = (wchar_t) *s;
len = 1;
}
else
len = mbtowc (pwcs, s, n);
if (len < 1)
{
/* Return an error. */
written = (size_t) -1;
break;
}
else
{
/* Multibyte character converted. */
++pwcs;
++written;
s += len;
n -= len;
}
}
/* Terminate the string if it has space. */
if (n > 0)
*pwcs = (wchar_t) 0;
/* Restore the old shift state. */
_mb_shift = save_shift;
/* Return how many we wrote (or maybe an error). */
return written;
}