1 /* $NetBSD: ungetwc.c,v 1.1 2001/12/07 11:47:44 yamt Exp $ */ 2 3 /*- 4 * Copyright (c)2001 Citrus Project, 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $Citrus$ 29 */ 30 31 #include <assert.h> 32 #include <errno.h> 33 #include <stdio.h> 34 #include <wchar.h> 35 #include "local.h" 36 #include "reentrant.h" 37 38 wint_t 39 ungetwc(wint_t wc, FILE *fp) 40 { 41 struct wchar_io_data *wcio; 42 43 _DIAGASSERT(fp); 44 45 if (wc == WEOF) 46 return WEOF; 47 48 FLOCKFILE(fp); 49 _SET_ORIENTATION(fp, 1); 50 /* 51 * XXX since we have no way to transform a wchar string to 52 * a char string in reverse order, we can't use ungetc. 53 */ 54 /* XXX should we flush ungetc buffer? */ 55 56 wcio = WCIO_GET(fp); 57 if (wcio == 0) { 58 FUNLOCKFILE(fp); 59 errno = ENOMEM; /* XXX */ 60 return WEOF; 61 } 62 63 if (wcio->wcio_ungetwc_inbuf >= WCIO_UNGETWC_BUFSIZE) { 64 FUNLOCKFILE(fp); 65 return WEOF; 66 } 67 68 wcio->wcio_ungetwc_buf[wcio->wcio_ungetwc_inbuf++] = wc; 69 __sclearerr(fp); 70 FUNLOCKFILE(fp); 71 72 return wc; 73 } 74