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ungetwc.c revision 1.1.2.3
      1  1.1.2.3  nathanw /* $NetBSD: ungetwc.c,v 1.1.2.3 2002/02/06 23:18:51 nathanw Exp $ */
      2  1.1.2.2  nathanw 
      3  1.1.2.2  nathanw /*-
      4  1.1.2.2  nathanw  * Copyright (c)2001 Citrus Project,
      5  1.1.2.2  nathanw  * All rights reserved.
      6  1.1.2.2  nathanw  *
      7  1.1.2.2  nathanw  * Redistribution and use in source and binary forms, with or without
      8  1.1.2.2  nathanw  * modification, are permitted provided that the following conditions
      9  1.1.2.2  nathanw  * are met:
     10  1.1.2.2  nathanw  * 1. Redistributions of source code must retain the above copyright
     11  1.1.2.2  nathanw  *    notice, this list of conditions and the following disclaimer.
     12  1.1.2.2  nathanw  * 2. Redistributions in binary form must reproduce the above copyright
     13  1.1.2.2  nathanw  *    notice, this list of conditions and the following disclaimer in the
     14  1.1.2.2  nathanw  *    documentation and/or other materials provided with the distribution.
     15  1.1.2.2  nathanw  *
     16  1.1.2.2  nathanw  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  1.1.2.2  nathanw  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  1.1.2.2  nathanw  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  1.1.2.2  nathanw  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  1.1.2.2  nathanw  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  1.1.2.2  nathanw  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  1.1.2.2  nathanw  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  1.1.2.2  nathanw  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  1.1.2.2  nathanw  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  1.1.2.2  nathanw  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  1.1.2.2  nathanw  * SUCH DAMAGE.
     27  1.1.2.2  nathanw  *
     28  1.1.2.2  nathanw  * $Citrus$
     29  1.1.2.2  nathanw  */
     30  1.1.2.2  nathanw 
     31  1.1.2.2  nathanw #include <assert.h>
     32  1.1.2.2  nathanw #include <errno.h>
     33  1.1.2.2  nathanw #include <stdio.h>
     34  1.1.2.2  nathanw #include <wchar.h>
     35  1.1.2.2  nathanw #include "reentrant.h"
     36  1.1.2.3  nathanw #include "local.h"
     37  1.1.2.2  nathanw 
     38  1.1.2.2  nathanw wint_t
     39  1.1.2.2  nathanw ungetwc(wint_t wc, FILE *fp)
     40  1.1.2.2  nathanw {
     41  1.1.2.2  nathanw 	struct wchar_io_data *wcio;
     42  1.1.2.2  nathanw 
     43  1.1.2.2  nathanw 	_DIAGASSERT(fp);
     44  1.1.2.2  nathanw 
     45  1.1.2.2  nathanw 	if (wc == WEOF)
     46  1.1.2.2  nathanw 		return WEOF;
     47  1.1.2.2  nathanw 
     48  1.1.2.2  nathanw 	FLOCKFILE(fp);
     49  1.1.2.2  nathanw 	_SET_ORIENTATION(fp, 1);
     50  1.1.2.2  nathanw 	/*
     51  1.1.2.2  nathanw 	 * XXX since we have no way to transform a wchar string to
     52  1.1.2.2  nathanw 	 * a char string in reverse order, we can't use ungetc.
     53  1.1.2.2  nathanw 	 */
     54  1.1.2.2  nathanw 	/* XXX should we flush ungetc buffer? */
     55  1.1.2.2  nathanw 
     56  1.1.2.2  nathanw 	wcio = WCIO_GET(fp);
     57  1.1.2.2  nathanw 	if (wcio == 0) {
     58  1.1.2.2  nathanw 		FUNLOCKFILE(fp);
     59  1.1.2.2  nathanw 		errno = ENOMEM; /* XXX */
     60  1.1.2.2  nathanw 		return WEOF;
     61  1.1.2.2  nathanw 	}
     62  1.1.2.2  nathanw 
     63  1.1.2.2  nathanw 	if (wcio->wcio_ungetwc_inbuf >= WCIO_UNGETWC_BUFSIZE) {
     64  1.1.2.2  nathanw 		FUNLOCKFILE(fp);
     65  1.1.2.2  nathanw 		return WEOF;
     66  1.1.2.2  nathanw 	}
     67  1.1.2.2  nathanw 
     68  1.1.2.2  nathanw 	wcio->wcio_ungetwc_buf[wcio->wcio_ungetwc_inbuf++] = wc;
     69  1.1.2.2  nathanw 	__sclearerr(fp);
     70  1.1.2.2  nathanw 	FUNLOCKFILE(fp);
     71  1.1.2.2  nathanw 
     72  1.1.2.2  nathanw 	return wc;
     73  1.1.2.2  nathanw }
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