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wcstod.c revision 1.8 
      1 /* $NetBSD: wcstod.c,v 1.8 2006/04/13 01:25:13 tnozaki Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2002 Tim J. Robbins
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  *
     28  * Original version ID:
     29  *   FreeBSD: /repoman/r/ncvs/src/lib/libc/locale/wcstod.c,v 1.4 2004/04/07 09:47:56 tjr Exp
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 __RCSID("$NetBSD: wcstod.c,v 1.8 2006/04/13 01:25:13 tnozaki Exp $");
     35 #endif /* LIBC_SCCS and not lint */
     36 
     37 #include <assert.h>
     38 #include <errno.h>
     39 #include <stdlib.h>
     40 #include <string.h>
     41 #include <wchar.h>
     42 #include <wctype.h>
     43 
     44 /*
     45  * Convert a string to a double-precision number.
     46  *
     47  * This is the wide-character counterpart of strtod(). So that we do not
     48  * have to duplicate the code of strtod() here, we convert the supplied
     49  * wide character string to multibyte and call strtod() on the result.
     50  * This assumes that the multibyte encoding is compatible with ASCII
     51  * for at least the digits, radix character and letters.
     52  */
     53 double
     54 wcstod(const wchar_t * __restrict nptr, wchar_t ** __restrict endptr)
     55 {
     56 	const wchar_t *src, *start;
     57 	double val;
     58 	char *buf, *end;
     59 	size_t bufsiz, len;
     60 
     61 	_DIAGASSERT(nptr != NULL);
     62 	/* endptr may be null */
     63 
     64 	src = nptr;
     65 	while (iswspace((wint_t)*src) != 0)
     66 		++src;
     67 	if (*src == L'\0')
     68 		goto no_convert;
     69 
     70 	/*
     71 	 * Convert the supplied numeric wide char. string to multibyte.
     72 	 *
     73 	 * We could attempt to find the end of the numeric portion of the
     74 	 * wide char. string to avoid converting unneeded characters but
     75 	 * choose not to bother; optimising the uncommon case where
     76 	 * the input string contains a lot of text after the number
     77 	 * duplicates a lot of strtod()'s functionality and slows down the
     78 	 * most common cases.
     79 	 */
     80 	start = src;
     81 	len = wcstombs(NULL, src, 0);
     82 	if (len == (size_t)-1)
     83 		/* errno = EILSEQ */
     84 		goto no_convert;
     85 
     86 	_DIAGASSERT(len > 0);
     87 
     88 	bufsiz = len;
     89 	buf = (void *)malloc(bufsiz + 1);
     90 	if (buf == NULL)
     91 		/* errno = ENOMEM */
     92 		goto no_convert;
     93 
     94 	len = wcstombs(buf, src, bufsiz + 1);
     95 
     96 	_DIAGASSERT(len == bufsiz);
     97 	_DIAGASSERT(buf[len] == '\0');
     98 
     99 	/* Let strtod() do most of the work for us. */
    100 	val = strtod(buf, &end);
    101 	if (buf == end) {
    102 		free(buf);
    103 		goto no_convert;
    104 	}
    105 
    106 	/*
    107 	 * We only know where the number ended in the _multibyte_
    108 	 * representation of the string. If the caller wants to know
    109 	 * where it ended, count multibyte characters to find the
    110 	 * corresponding position in the wide char string.
    111 	 */
    112 	if (endptr != NULL)
    113 		/* XXX Assume each wide char is one byte. */
    114 		*endptr = __UNCONST(start + (size_t)(end - buf));
    115 
    116 	free(buf);
    117 
    118 	return val;
    119 
    120 no_convert:
    121 	if (endptr != NULL)
    122 		*endptr = __UNCONST(nptr);
    123 	return 0;
    124 }
    125