xref: /freebsd/lib/libc/locale/wcstod.c (revision 1d386b48a555f61cb7325543adbbb5c3f3407a66)
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 <sys/cdefs.h>
35 #include <stdlib.h>
36 #include <wchar.h>
37 #include <wctype.h>
38 #include "xlocale_private.h"
39 
40 /*
41  * Convert a string to a double-precision number.
42  *
43  * This is the wide-character counterpart of strtod(). So that we do not
44  * have to duplicate the code of strtod() here, we convert the supplied
45  * wide character string to multibyte and call strtod() on the result.
46  * This assumes that the multibyte encoding is compatible with ASCII
47  * for at least the digits, radix character and letters.
48  */
49 double
50 wcstod_l(const wchar_t * __restrict nptr, wchar_t ** __restrict endptr,
51 		locale_t locale)
52 {
53 	static const mbstate_t initial;
54 	mbstate_t mbs;
55 	double val;
56 	char *buf, *end;
57 	const wchar_t *wcp;
58 	size_t len;
59 	size_t spaces;
60 	FIX_LOCALE(locale);
61 
62 	wcp = nptr;
63 	spaces = 0;
64 	while (iswspace_l(*wcp, locale)) {
65 		wcp++;
66 		spaces++;
67 	}
68 
69 	/*
70 	 * Convert the supplied numeric wide char. string to multibyte.
71 	 *
72 	 * We could attempt to find the end of the numeric portion of the
73 	 * wide char. string to avoid converting unneeded characters but
74 	 * choose not to bother; optimising the uncommon case where
75 	 * the input string contains a lot of text after the number
76 	 * duplicates a lot of strtod()'s functionality and slows down the
77 	 * most common cases.
78 	 */
79 	mbs = initial;
80 	if ((len = wcsrtombs_l(NULL, &wcp, 0, &mbs, locale)) == (size_t)-1) {
81 		if (endptr != NULL)
82 			*endptr = (wchar_t *)nptr;
83 		return (0.0);
84 	}
85 	if ((buf = malloc(len + 1)) == NULL) {
86 		if (endptr != NULL)
87 			*endptr = (wchar_t *)nptr;
88 		return (0.0);
89 	}
90 	mbs = initial;
91 	wcsrtombs_l(buf, &wcp, len + 1, &mbs, locale);
92 
93 	/* Let strtod() do most of the work for us. */
94 	val = strtod_l(buf, &end, locale);
95 
96 	/*
97 	 * We only know where the number ended in the _multibyte_
98 	 * representation of the string. If the caller wants to know
99 	 * where it ended, count multibyte characters to find the
100 	 * corresponding position in the wide char string.
101 	 */
102 	if (endptr != NULL) {
103 		*endptr = (wchar_t *)nptr + (end - buf);
104 		if (buf != end)
105 			*endptr += spaces;
106 	}
107 
108 	free(buf);
109 
110 	return (val);
111 }
112 double
113 wcstod(const wchar_t * __restrict nptr, wchar_t ** __restrict endptr)
114 {
115 	return wcstod_l(nptr, endptr, __get_locale());
116 }
117