1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <uchar.h>
33#include "mblocal.h"
34
35typedef struct {
36	char16_t	trail_surrogate;
37	mbstate_t	c32_mbstate;
38} _Char16State;
39
40size_t
41mbrtoc16_l(char16_t * __restrict pc16, const char * __restrict s, size_t n,
42    mbstate_t * __restrict ps, locale_t locale)
43{
44	_Char16State *cs;
45	char32_t c32;
46	ssize_t len;
47
48	FIX_LOCALE(locale);
49	if (ps == NULL)
50		ps = &(XLOCALE_CTYPE(locale)->mbrtoc16);
51	cs = (_Char16State *)ps;
52
53	/*
54	 * Call straight into mbrtoc32_l() if we don't need to return a
55	 * character value. According to the spec, if s is a null
56	 * pointer, the value of parameter pc16 is also ignored.
57	 */
58	if (pc16 == NULL || s == NULL) {
59		cs->trail_surrogate = 0;
60		return (mbrtoc32_l(NULL, s, n, &cs->c32_mbstate, locale));
61	}
62
63	/* Return the trail surrogate from the previous invocation. */
64	if (cs->trail_surrogate >= 0xdc00 && cs->trail_surrogate <= 0xdfff) {
65		*pc16 = cs->trail_surrogate;
66		cs->trail_surrogate = 0;
67		return ((size_t)-3);
68	}
69
70	len = mbrtoc32_l(&c32, s, n, &cs->c32_mbstate, locale);
71	if (len >= 0) {
72		if (c32 < 0x10000) {
73			/* Fits in one UTF-16 character. */
74			*pc16 = c32;
75		} else {
76			/* Split up in a surrogate pair. */
77			c32 -= 0x10000;
78			*pc16 = 0xd800 | (c32 >> 10);
79			cs->trail_surrogate = 0xdc00 | (c32 & 0x3ff);
80		}
81	}
82	return (len);
83}
84
85size_t
86mbrtoc16(char16_t * __restrict pc16, const char * __restrict s, size_t n,
87    mbstate_t * __restrict ps)
88{
89
90	return (mbrtoc16_l(pc16, s, n, ps, __get_locale()));
91}
92