xref: /freebsd/lib/libc/string/wcscoll.c (revision f4b37ed0f8b307b1f3f0f630ca725d68f1dff30d)
1 /*-
2  * Copyright (c) 2002 Tim J. Robbins
3  * All rights reserved.
4  *
5  * Copyright (c) 2011 The FreeBSD Foundation
6  * All rights reserved.
7  * Portions of this software were developed by David Chisnall
8  * under sponsorship from the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <errno.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <wchar.h>
39 #include "collate.h"
40 
41 static char *__mbsdup(const wchar_t *);
42 
43 /*
44  * Placeholder implementation of wcscoll(). Attempts to use the single-byte
45  * collation ordering where possible, and falls back on wcscmp() in locales
46  * with extended character sets.
47  */
48 int
49 wcscoll_l(const wchar_t *ws1, const wchar_t *ws2, locale_t locale)
50 {
51 	char *mbs1, *mbs2;
52 	int diff, sverrno;
53 	FIX_LOCALE(locale);
54 	struct xlocale_collate *table =
55 		(struct xlocale_collate*)locale->components[XLC_COLLATE];
56 
57 	if (table->__collate_load_error || MB_CUR_MAX > 1)
58 		/*
59 		 * Locale has no special collating order, could not be
60 		 * loaded, or has an extended character set; do a fast binary
61 		 * comparison.
62 		 */
63 		return (wcscmp(ws1, ws2));
64 
65 	if ((mbs1 = __mbsdup(ws1)) == NULL || (mbs2 = __mbsdup(ws2)) == NULL) {
66 		/*
67 		 * Out of memory or illegal wide chars; fall back to wcscmp()
68 		 * but leave errno indicating the error. Callers that don't
69 		 * check for error will get a reasonable but often slightly
70 		 * incorrect result.
71 		 */
72 		sverrno = errno;
73 		free(mbs1);
74 		errno = sverrno;
75 		return (wcscmp(ws1, ws2));
76 	}
77 
78 	diff = strcoll_l(mbs1, mbs2, locale);
79 	sverrno = errno;
80 	free(mbs1);
81 	free(mbs2);
82 	errno = sverrno;
83 
84 	return (diff);
85 }
86 
87 int
88 wcscoll(const wchar_t *ws1, const wchar_t *ws2)
89 {
90 	return wcscoll_l(ws1, ws2, __get_locale());
91 }
92 
93 static char *
94 __mbsdup(const wchar_t *ws)
95 {
96 	static const mbstate_t initial;
97 	mbstate_t st;
98 	const wchar_t *wcp;
99 	size_t len;
100 	char *mbs;
101 
102 	wcp = ws;
103 	st = initial;
104 	if ((len = wcsrtombs(NULL, &wcp, 0, &st)) == (size_t)-1)
105 		return (NULL);
106 	if ((mbs = malloc(len + 1)) == NULL)
107 		return (NULL);
108 	st = initial;
109 	wcsrtombs(mbs, &ws, len + 1, &st);
110 
111 	return (mbs);
112 }
113