minix/lib/libc/stdio/ungetwc.c

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/* $NetBSD: ungetwc.c,v 1.3 2005/06/12 05:21:27 lukem Exp $ */
/*-
* Copyright (c)2001 Citrus Project,
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Citrus$
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: ungetwc.c,v 1.3 2005/06/12 05:21:27 lukem Exp $");
#endif /* LIBC_SCCS and not lint */
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <wchar.h>
#include "reentrant.h"
#include "local.h"
wint_t
ungetwc(wint_t wc, FILE *fp)
{
struct wchar_io_data *wcio;
_DIAGASSERT(fp);
if (wc == WEOF)
return WEOF;
FLOCKFILE(fp);
_SET_ORIENTATION(fp, 1);
/*
* XXX since we have no way to transform a wchar string to
* a char string in reverse order, we can't use ungetc.
*/
/* XXX should we flush ungetc buffer? */
wcio = WCIO_GET(fp);
if (wcio == 0) {
FUNLOCKFILE(fp);
errno = ENOMEM; /* XXX */
return WEOF;
}
if (wcio->wcio_ungetwc_inbuf >= WCIO_UNGETWC_BUFSIZE) {
FUNLOCKFILE(fp);
return WEOF;
}
wcio->wcio_ungetwc_buf[wcio->wcio_ungetwc_inbuf++] = wc;
__sclearerr(fp);
FUNLOCKFILE(fp);
return wc;
}