xref: /freebsd/lib/libc/locale/wcstod.c (revision 4543ef516683042d46f3bd3bb8a4f3f746e00499)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2002 Tim J. Robbins
5  * All rights reserved.
6  *
7  * Copyright (c) 2011 The FreeBSD Foundation
8  *
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 <stdlib.h>
35 #include <wchar.h>
36 #include <wctype.h>
37 #include "xlocale_private.h"
38 
39 /*
40  * Convert a string to a double-precision number.
41  *
42  * This is the wide-character counterpart of strtod(). So that we do not
43  * have to duplicate the code of strtod() here, we convert the supplied
44  * wide character string to multibyte and call strtod() on the result.
45  * This assumes that the multibyte encoding is compatible with ASCII
46  * for at least the digits, radix character and letters.
47  */
48 double
49 wcstod_l(const wchar_t * __restrict nptr, wchar_t ** __restrict endptr,
50 		locale_t locale)
51 {
52 	static const mbstate_t initial;
53 	mbstate_t mbs;
54 	double val;
55 	char *buf, *end;
56 	const wchar_t *wcp;
57 	size_t len;
58 	size_t spaces;
59 	FIX_LOCALE(locale);
60 
61 	wcp = nptr;
62 	spaces = 0;
63 	while (iswspace_l(*wcp, locale)) {
64 		wcp++;
65 		spaces++;
66 	}
67 
68 	/*
69 	 * Convert the supplied numeric wide char. string to multibyte.
70 	 *
71 	 * We could attempt to find the end of the numeric portion of the
72 	 * wide char. string to avoid converting unneeded characters but
73 	 * choose not to bother; optimising the uncommon case where
74 	 * the input string contains a lot of text after the number
75 	 * duplicates a lot of strtod()'s functionality and slows down the
76 	 * most common cases.
77 	 */
78 	mbs = initial;
79 	if ((len = wcsrtombs_l(NULL, &wcp, 0, &mbs, locale)) == (size_t)-1) {
80 		if (endptr != NULL)
81 			*endptr = (wchar_t *)nptr;
82 		return (0.0);
83 	}
84 	if ((buf = malloc(len + 1)) == NULL) {
85 		if (endptr != NULL)
86 			*endptr = (wchar_t *)nptr;
87 		return (0.0);
88 	}
89 	mbs = initial;
90 	wcsrtombs_l(buf, &wcp, len + 1, &mbs, locale);
91 
92 	/* Let strtod() do most of the work for us. */
93 	val = strtod_l(buf, &end, locale);
94 
95 	/*
96 	 * We only know where the number ended in the _multibyte_
97 	 * representation of the string. If the caller wants to know
98 	 * where it ended, count multibyte characters to find the
99 	 * corresponding position in the wide char string.
100 	 */
101 	if (endptr != NULL) {
102 		*endptr = (wchar_t *)nptr + (end - buf);
103 		if (buf != end)
104 			*endptr += spaces;
105 	}
106 
107 	free(buf);
108 
109 	return (val);
110 }
111 double
112 wcstod(const wchar_t * __restrict nptr, wchar_t ** __restrict endptr)
113 {
114 	return wcstod_l(nptr, endptr, __get_locale());
115 }
116