xref: /freebsd/lib/libc/string/wcscoll.c (revision f0a75d274af375d15b97b830966b99a02b7db911)
1 /*-
2  * Copyright (c) 2002 Tim J. Robbins
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("$FreeBSD$");
29 
30 #include <errno.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <wchar.h>
34 #include "collate.h"
35 
36 static char *__mbsdup(const wchar_t *);
37 
38 /*
39  * Placeholder implementation of wcscoll(). Attempts to use the single-byte
40  * collation ordering where possible, and falls back on wcscmp() in locales
41  * with extended character sets.
42  */
43 int
44 wcscoll(const wchar_t *ws1, const wchar_t *ws2)
45 {
46 	char *mbs1, *mbs2;
47 	int diff, sverrno;
48 
49 	if (__collate_load_error || MB_CUR_MAX > 1)
50 		/*
51 		 * Locale has no special collating order, could not be
52 		 * loaded, or has an extended character set; do a fast binary
53 		 * comparison.
54 		 */
55 		return (wcscmp(ws1, ws2));
56 
57 	if ((mbs1 = __mbsdup(ws1)) == NULL || (mbs2 = __mbsdup(ws2)) == NULL) {
58 		/*
59 		 * Out of memory or illegal wide chars; fall back to wcscmp()
60 		 * but leave errno indicating the error. Callers that don't
61 		 * check for error will get a reasonable but often slightly
62 		 * incorrect result.
63 		 */
64 		sverrno = errno;
65 		free(mbs1);
66 		errno = sverrno;
67 		return (wcscmp(ws1, ws2));
68 	}
69 
70 	diff = strcoll(mbs1, mbs2);
71 	sverrno = errno;
72 	free(mbs1);
73 	free(mbs2);
74 	errno = sverrno;
75 
76 	return (diff);
77 }
78 
79 static char *
80 __mbsdup(const wchar_t *ws)
81 {
82 	static const mbstate_t initial;
83 	mbstate_t st;
84 	const wchar_t *wcp;
85 	size_t len;
86 	char *mbs;
87 
88 	wcp = ws;
89 	st = initial;
90 	if ((len = wcsrtombs(NULL, &wcp, 0, &st)) == (size_t)-1)
91 		return (NULL);
92 	if ((mbs = malloc(len + 1)) == NULL)
93 		return (NULL);
94 	st = initial;
95 	wcsrtombs(mbs, &ws, len + 1, &st);
96 
97 	return (mbs);
98 }
99