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 (c) 1996-1998 by Sun Microsystems, Inc.
24  * All rights reserved.
25  */
26 
27 /* LINTLIBRARY */
28 
29 /*
30  * wio_get.c
31  *
32  * Wide I/O Library
33  *
34  * Copyright 1990, 1995 by Mortice Kern Systems Inc.  All rights reserved.
35  *
36  */
37 
38 #if M_RCSID
39 #ifndef lint
40 static char rcsID[] =
41 "$Header: /team/ps/sun_xcurses/archive/local_changes/xcurses/src/lib/"
42 "libxcurses/src/libc/wide/rcs/wio_get.c 1.3 1998/05/22 17:56:47 "
43 "cbates Exp $";
44 #endif
45 #endif
46 
47 #include <mks.h>
48 #include <errno.h>
49 #include <m_wio.h>
50 
51 /*
52  * Return a wide character or WEOF for EOF or error.
53  *
54  * The function referenced by "get" is passed the pointer "object"
55  * and returns an input byte or EOF if no further data available.
56  *
57  * This mechanism is used to do conversions of byte strings or
58  * streams into wide characters without loss of information in the
59  * case of a bad multibyte character conversion.  The bad multibyte
60  * sequence is passed through as individual bytes.
61  */
62 wint_t
m_wio_get(t_wide_io * wio)63 m_wio_get(t_wide_io *wio)
64 {
65 	int	ch;
66 	wchar_t	wc;
67 
68 	if (wio == NULL || wio->get == (int (*)(void *)) NULL) {
69 		errno = EINVAL;
70 		return (-1);
71 	}
72 
73 	/* Do still have bytes available? */
74 	if (wio->_next < wio->_size) {
75 		return ((wint_t)wio->_mb[wio->_next++]);
76 	}
77 
78 	/* Read in enough bytes to convert a multibyte character. */
79 	wio->_size = 0;
80 	for (wio->_next = 0; wio->_next < (int)MB_CUR_MAX; ) {
81 		if ((ch = (*wio->get)(wio->object)) == EOF) {
82 			break;
83 		}
84 
85 		wio->_mb[wio->_next] = (unsigned char)ch;
86 
87 		wio->_size = mbtowc(&wc, (char *)wio->_mb, wio->_next + 1);
88 
89 		++wio->_next;
90 
91 		if (0 <= wio->_size) {
92 			/* Remember the number of bytes converted. */
93 			wio->_size = wio->_next;
94 
95 			return ((wint_t) wc);
96 		}
97 	}
98 
99 	/*
100 	 * If we fill the multibyte character buffer or receive an
101 	 * EOF without recognising a multibyte character, then we
102 	 * will return individual bytes from the buffer.  The buffer
103 	 * is restored to its state before the bogus byte sequence
104 	 * was read.
105 	 */
106 	wio->_size = wio->_next;
107 	wio->_next = 0;
108 
109 	return (0 < wio->_size ? (wint_t) wio->_mb[wio->_next++] : WEOF);
110 }
111