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 <uchar.h>
30#include "mblocal.h"
31
32typedef struct {
33	char16_t	trail_surrogate;
34	mbstate_t	c32_mbstate;
35} _Char16State;
36
37size_t
38mbrtoc16_l(char16_t * __restrict pc16, const char * __restrict s, size_t n,
39    mbstate_t * __restrict ps, locale_t locale)
40{
41	_Char16State *cs;
42	char32_t c32;
43	ssize_t len;
44
45	FIX_LOCALE(locale);
46	if (ps == NULL)
47		ps = &(XLOCALE_CTYPE(locale)->mbrtoc16);
48	cs = (_Char16State *)ps;
49
50	/*
51	 * Call straight into mbrtoc32_l() if we don't need to return a
52	 * character value. According to the spec, if s is a null
53	 * pointer, the value of parameter pc16 is also ignored.
54	 */
55	if (pc16 == NULL || s == NULL) {
56		cs->trail_surrogate = 0;
57		return (mbrtoc32_l(NULL, s, n, &cs->c32_mbstate, locale));
58	}
59
60	/* Return the trail surrogate from the previous invocation. */
61	if (cs->trail_surrogate >= 0xdc00 && cs->trail_surrogate <= 0xdfff) {
62		*pc16 = cs->trail_surrogate;
63		cs->trail_surrogate = 0;
64		return ((size_t)-3);
65	}
66
67	len = mbrtoc32_l(&c32, s, n, &cs->c32_mbstate, locale);
68	if (len >= 0) {
69		if (c32 < 0x10000) {
70			/* Fits in one UTF-16 character. */
71			*pc16 = c32;
72		} else {
73			/* Split up in a surrogate pair. */
74			c32 -= 0x10000;
75			*pc16 = 0xd800 | (c32 >> 10);
76			cs->trail_surrogate = 0xdc00 | (c32 & 0x3ff);
77		}
78	}
79	return (len);
80}
81
82size_t
83mbrtoc16(char16_t * __restrict pc16, const char * __restrict s, size_t n,
84    mbstate_t * __restrict ps)
85{
86
87	return (mbrtoc16_l(pc16, s, n, ps, __get_locale()));
88}
89