xref: /titanic_52/usr/src/lib/libc/port/locale/ungetwc.c (revision 4297a3b0d0a35d80f86fff155e288e885a100e6d)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1986 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
32  * Use is subject to license terms.
33  */
34 
35 /*	This module is created for NLS on Sep.03.86		*/
36 
37 /*
38  * Ungetwc saves the process code c into the one character buffer
39  * associated with an input stream "iop". That character, c,
40  * will be returned by the next getwc call on that stream.
41  */
42 
43 #include "lint.h"
44 #include "file64.h"
45 #include "mse_int.h"
46 #include <stdio.h>
47 #include <stdlib.h>
48 #include <widec.h>
49 #include <limits.h>
50 #include <errno.h>
51 #include "libc.h"
52 #include "stdiom.h"
53 #include "mse.h"
54 
55 static wint_t
56 __ungetwc_impl(wint_t wc, FILE *iop, int orient)
57 {
58 	char		mbs[MB_LEN_MAX];
59 	unsigned char	*p;
60 	int		n;
61 	rmutex_t	*lk;
62 
63 	FLOCKFILE(lk, iop);
64 
65 	if (orient && GET_NO_MODE(iop)) {
66 		_setorientation(iop, _WC_MODE);
67 	}
68 	if ((wc == WEOF) || ((iop->_flag & _IOREAD) == 0)) {
69 		FUNLOCKFILE(lk);
70 		return (WEOF);
71 	}
72 
73 	n = wctomb(mbs, (wchar_t)wc);
74 	if (n <= 0) {
75 		FUNLOCKFILE(lk);
76 		return (WEOF);
77 	}
78 
79 	if (iop->_ptr <= iop->_base) {
80 		if (iop->_base == NULL) {
81 			FUNLOCKFILE(lk);
82 			return (WEOF);
83 		}
84 		if (iop->_ptr == iop->_base && iop->_cnt == 0) {
85 			++iop->_ptr;
86 		} else if ((iop->_ptr - n) < (iop->_base - PUSHBACK)) {
87 			FUNLOCKFILE(lk);
88 			return (WEOF);
89 		}
90 	}
91 
92 	p = (unsigned char *)(mbs + n - 1);
93 	while (n--) {
94 		*--(iop)->_ptr = (*p--);
95 		++(iop)->_cnt;
96 	}
97 	iop->_flag &= ~_IOEOF;
98 	FUNLOCKFILE(lk);
99 	return (wc);
100 }
101 
102 
103 wint_t
104 __ungetwc_xpg5(wint_t wc, FILE *iop)
105 {
106 	return (__ungetwc_impl(wc, iop, 1));
107 }
108 
109 wint_t
110 ungetwc(wint_t wc, FILE *iop)
111 {
112 	return (__ungetwc_impl(wc, iop, 0));
113 }
114