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      1 /*	$OpenBSD: ungetwc.c,v 1.5 2011/10/16 13:20:51 stsp Exp $	*/
      2 /* $NetBSD: ungetwc.c,v 1.2 2003/01/18 11:29:59 thorpej Exp $ */
      3 
      4 /*-
      5  * Copyright (c)2001 Citrus Project,
      6  * All rights reserved.
      7  *
      8  * Redistribution and use in source and binary forms, with or without
      9  * modification, are permitted provided that the following conditions
     10  * are met:
     11  * 1. Redistributions of source code must retain the above copyright
     12  *    notice, this list of conditions and the following disclaimer.
     13  * 2. Redistributions in binary form must reproduce the above copyright
     14  *    notice, this list of conditions and the following disclaimer in the
     15  *    documentation and/or other materials provided with the distribution.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     27  * SUCH DAMAGE.
     28  *
     29  * $Citrus$
     30  */
     31 
     32 #include <errno.h>
     33 #include <stdio.h>
     34 #include <wchar.h>
     35 #include "local.h"
     36 
     37 wint_t
     38 __ungetwc(wint_t wc, FILE *fp)
     39 {
     40 	struct wchar_io_data *wcio;
     41 
     42 	if (wc == WEOF)
     43 		return WEOF;
     44 
     45 	_SET_ORIENTATION(fp, 1);
     46 	/*
     47 	 * XXX since we have no way to transform a wchar string to
     48 	 * a char string in reverse order, we can't use ungetc.
     49 	 */
     50 	/* XXX should we flush ungetc buffer? */
     51 
     52 	wcio = WCIO_GET(fp);
     53 	if (wcio == 0) {
     54 		errno = ENOMEM; /* XXX */
     55 		return WEOF;
     56 	}
     57 
     58 	if (wcio->wcio_ungetwc_inbuf >= WCIO_UNGETWC_BUFSIZE) {
     59 		return WEOF;
     60 	}
     61 
     62 	wcio->wcio_ungetwc_buf[wcio->wcio_ungetwc_inbuf++] = wc;
     63 	__sclearerr(fp);
     64 
     65 	return wc;
     66 }
     67 
     68 wint_t
     69 ungetwc(wint_t wc, FILE *fp)
     70 {
     71 	wint_t r;
     72 
     73 	FLOCKFILE(fp);
     74 	r = __ungetwc(wc, fp);
     75 	FUNLOCKFILE(fp);
     76 	return (r);
     77 }
     78