xref: /freebsd/lib/libc/locale/tolower.c (revision 1db64f89363c97858961c4df0b7d02f3223723cf)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Paul Borman at Krystal Technologies.
9  *
10  * Copyright (c) 2011 The FreeBSD Foundation
11  *
12  * Portions of this software were developed by David Chisnall
13  * under sponsorship from the FreeBSD Foundation.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  */
39 
40 #include <ctype.h>
41 #include <stdio.h>
42 #include <runetype.h>
43 #include <wchar.h>
44 #include "mblocal.h"
45 
46 __ct_rune_t
47 ___tolower_l(__ct_rune_t c, locale_t l)
48 {
49 	size_t lim;
50 	FIX_LOCALE(l);
51 	_RuneRange *rr = &XLOCALE_CTYPE(l)->runes->__maplower_ext;
52 	_RuneEntry *base, *re;
53 
54 	if (c < 0 || c == EOF)
55 		return(c);
56 
57 	/* Binary search -- see bsearch.c for explanation. */
58 	base = rr->__ranges;
59 	for (lim = rr->__nranges; lim != 0; lim >>= 1) {
60 		re = base + (lim >> 1);
61 		if (re->__min <= c && c <= re->__max)
62 			return (re->__map + c - re->__min);
63 		else if (c > re->__max) {
64 			base = re + 1;
65 			lim--;
66 		}
67 	}
68 
69 	return(c);
70 }
71 __ct_rune_t
72 ___tolower(__ct_rune_t c)
73 {
74 	return ___tolower_l(c, __get_locale());
75 }
76