xref: /freebsd/lib/libc/locale/wcstod.c (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2002 Tim J. Robbins
5  * All rights reserved.
6  *
7  * Copyright (c) 2011 The FreeBSD Foundation
8  * All rights reserved.
9  * Portions of this software were developed by David Chisnall
10  * under sponsorship from the FreeBSD Foundation.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <stdlib.h>
38 #include <wchar.h>
39 #include <wctype.h>
40 #include "xlocale_private.h"
41 
42 /*
43  * Convert a string to a double-precision number.
44  *
45  * This is the wide-character counterpart of strtod(). So that we do not
46  * have to duplicate the code of strtod() here, we convert the supplied
47  * wide character string to multibyte and call strtod() on the result.
48  * This assumes that the multibyte encoding is compatible with ASCII
49  * for at least the digits, radix character and letters.
50  */
51 double
52 wcstod_l(const wchar_t * __restrict nptr, wchar_t ** __restrict endptr,
53 		locale_t locale)
54 {
55 	static const mbstate_t initial;
56 	mbstate_t mbs;
57 	double val;
58 	char *buf, *end;
59 	const wchar_t *wcp;
60 	size_t len;
61 	size_t spaces;
62 	FIX_LOCALE(locale);
63 
64 	wcp = nptr;
65 	spaces = 0;
66 	while (iswspace_l(*wcp, locale)) {
67 		wcp++;
68 		spaces++;
69 	}
70 
71 	/*
72 	 * Convert the supplied numeric wide char. string to multibyte.
73 	 *
74 	 * We could attempt to find the end of the numeric portion of the
75 	 * wide char. string to avoid converting unneeded characters but
76 	 * choose not to bother; optimising the uncommon case where
77 	 * the input string contains a lot of text after the number
78 	 * duplicates a lot of strtod()'s functionality and slows down the
79 	 * most common cases.
80 	 */
81 	mbs = initial;
82 	if ((len = wcsrtombs_l(NULL, &wcp, 0, &mbs, locale)) == (size_t)-1) {
83 		if (endptr != NULL)
84 			*endptr = (wchar_t *)nptr;
85 		return (0.0);
86 	}
87 	if ((buf = malloc(len + 1)) == NULL) {
88 		if (endptr != NULL)
89 			*endptr = (wchar_t *)nptr;
90 		return (0.0);
91 	}
92 	mbs = initial;
93 	wcsrtombs_l(buf, &wcp, len + 1, &mbs, locale);
94 
95 	/* Let strtod() do most of the work for us. */
96 	val = strtod_l(buf, &end, locale);
97 
98 	/*
99 	 * We only know where the number ended in the _multibyte_
100 	 * representation of the string. If the caller wants to know
101 	 * where it ended, count multibyte characters to find the
102 	 * corresponding position in the wide char string.
103 	 */
104 	if (endptr != NULL) {
105 		*endptr = (wchar_t *)nptr + (end - buf);
106 		if (buf != end)
107 			*endptr += spaces;
108 	}
109 
110 	free(buf);
111 
112 	return (val);
113 }
114 double
115 wcstod(const wchar_t * __restrict nptr, wchar_t ** __restrict endptr)
116 {
117 	return wcstod_l(nptr, endptr, __get_locale());
118 }
119