xref: /freebsd/lib/libc/locale/c16rtomb.c (revision 783d3ff6d7fae619db8a7990b8a6387de0c677b5)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2013 Ed Schouten <ed@FreeBSD.org>
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 
29 #include <errno.h>
30 #include <uchar.h>
31 #include "mblocal.h"
32 
33 typedef struct {
34 	char16_t	lead_surrogate;
35 	mbstate_t	c32_mbstate;
36 } _Char16State;
37 
38 size_t
39 c16rtomb_l(char * __restrict s, char16_t c16, mbstate_t * __restrict ps,
40     locale_t locale)
41 {
42 	_Char16State *cs;
43 	char32_t c32;
44 
45 	FIX_LOCALE(locale);
46 	if (ps == NULL)
47 		ps = &(XLOCALE_CTYPE(locale)->c16rtomb);
48 	cs = (_Char16State *)ps;
49 
50 	/* If s is a null pointer, the value of parameter c16 is ignored. */
51 	if (s == NULL) {
52 		c32 = 0;
53 	} else if (cs->lead_surrogate >= 0xd800 &&
54 	    cs->lead_surrogate <= 0xdbff) {
55 		/* We should see a trail surrogate now. */
56 		if (c16 < 0xdc00 || c16 > 0xdfff) {
57 			errno = EILSEQ;
58 			return ((size_t)-1);
59 		}
60 		c32 = 0x10000 + ((cs->lead_surrogate & 0x3ff) << 10 |
61 		    (c16 & 0x3ff));
62 	} else if (c16 >= 0xd800 && c16 <= 0xdbff) {
63 		/* Store lead surrogate for next invocation. */
64 		cs->lead_surrogate = c16;
65 		return (0);
66 	} else {
67 		/* Regular character. */
68 		c32 = c16;
69 	}
70 	cs->lead_surrogate = 0;
71 
72 	return (c32rtomb_l(s, c32, &cs->c32_mbstate, locale));
73 }
74 
75 size_t
76 c16rtomb(char * __restrict s, char16_t c16, mbstate_t * __restrict ps)
77 {
78 
79 	return (c16rtomb_l(s, c16, ps, __get_locale()));
80 }
81