mbrtoc16.c revision 331722 
1/*-
2 * Copyright (c) 2013 Ed Schouten <ed@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: stable/11/lib/libc/locale/mbrtoc16.c 331722 2018-03-29 02:50:57Z eadler $");
29
30#include <uchar.h>
31#include "xlocale_private.h"
32
33typedef struct {
34	char16_t	trail_surrogate;
35	mbstate_t	c32_mbstate;
36} _Char16State;
37
38size_t
39mbrtoc16_l(char16_t * __restrict pc16, const char * __restrict s, size_t n,
40    mbstate_t * __restrict ps, locale_t locale)
41{
42	_Char16State *cs;
43	char32_t c32;
44	ssize_t len;
45
46	FIX_LOCALE(locale);
47	if (ps == NULL)
48		ps = &locale->mbrtoc16;
49	cs = (_Char16State *)ps;
50
51	/*
52	 * Call straight into mbrtoc32_l() if we don't need to return a
53	 * character value. According to the spec, if s is a null
54	 * pointer, the value of parameter pc16 is also ignored.
55	 */
56	if (pc16 == NULL || s == NULL) {
57		cs->trail_surrogate = 0;
58		return (mbrtoc32_l(NULL, s, n, &cs->c32_mbstate, locale));
59	}
60
61	/* Return the trail surrogate from the previous invocation. */
62	if (cs->trail_surrogate >= 0xdc00 && cs->trail_surrogate <= 0xdfff) {
63		*pc16 = cs->trail_surrogate;
64		cs->trail_surrogate = 0;
65		return ((size_t)-3);
66	}
67
68	len = mbrtoc32_l(&c32, s, n, &cs->c32_mbstate, locale);
69	if (len >= 0) {
70		if (c32 < 0x10000) {
71			/* Fits in one UTF-16 character. */
72			*pc16 = c32;
73		} else {
74			/* Split up in a surrogate pair. */
75			c32 -= 0x10000;
76			*pc16 = 0xd800 | (c32 >> 10);
77			cs->trail_surrogate = 0xdc00 | (c32 & 0x3ff);
78		}
79	}
80	return (len);
81}
82
83size_t
84mbrtoc16(char16_t * __restrict pc16, const char * __restrict s, size_t n,
85    mbstate_t * __restrict ps)
86{
87
88	return (mbrtoc16_l(pc16, s, n, ps, __get_locale()));
89}
90