locale/FreeBSD/wcstod.c

   1 /*-
   2  * Copyright (c) 2002 Tim J. Robbins
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD: src/lib/libc/locale/wcstod.c,v 1.2 2003/02/22 00:06:05 tjr Exp $");
  29
  30 #include <stdlib.h>
  31 #include <wchar.h>
  32 #include <wctype.h>
  33
  34 /*
  35  * Convert a string to a double-precision number.
  36  *
  37  * This is the wide-character counterpart of strtod(). So that we do not
  38  * have to duplicate the code of strtod() here, we convert the supplied
  39  * wide character string to multibyte and call strtod() on the result.
  40  * This assumes that the multibyte encoding is compatible with ASCII
  41  * for at least the digits, radix character and letters.
  42  */
  43 double
  44 wcstod(const wchar_t * __restrict nptr, wchar_t ** __restrict endptr)
  45 {
  46         static const mbstate_t initial;
  47         mbstate_t state;
  48         double val;
  49         char *buf, *end, *p;
  50         const wchar_t *wcp;
  51         size_t clen, len;
  52
  53         while (iswspace(*nptr))
  54                 nptr++;
  55
  56         /*
  57          * Convert the supplied numeric wide char. string to multibyte.
  58          *
  59          * We could attempt to find the end of the numeric portion of the
  60          * wide char. string to avoid converting unneeded characters but
  61          * choose not to bother; optimising the uncommon case where
  62          * the input string contains a lot of text after the number
  63          * duplicates a lot of strtod()'s functionality and slows down the
  64          * most common cases.
  65          */
  66         state = initial;
  67         wcp = nptr;
  68         if ((len = wcsrtombs(NULL, &wcp, 0, &state)) == (size_t)-1) {
  69                 if (endptr != NULL)
  70                         *endptr = (wchar_t *)nptr;
  71                 return (0.0);
  72         }
  73         if ((buf = malloc(len + 1)) == NULL)
  74                 return (0.0);
  75         state = initial;
  76         wcsrtombs(buf, &wcp, len + 1, &state);
  77
  78         /* Let strtod() do most of the work for us. */
  79         val = strtod(buf, &end);
  80
  81         /*
  82          * We only know where the number ended in the _multibyte_
  83          * representation of the string. If the caller wants to know
  84          * where it ended, count multibyte characters to find the
  85          * corresponding position in the wide char string.
  86          */
  87         if (endptr != NULL) {
  88 #if 1                                   /* Fast, assume 1:1 WC:MBS mapping. */
  89                 *endptr = (wchar_t *)nptr + (end - buf);
  90                 (void)clen;
  91                 (void)p;
  92 #else                                   /* Slow, conservative approach. */
  93                 state = initial;
  94                 *endptr = (wchar_t *)nptr;
  95                 p = buf;
  96                 while (p < end &&
  97                     (clen = mbrlen(p, end - p, &state)) > 0) {
  98                         p += clen;
  99                         (*endptr)++;
 100                 }
 101 #endif
 102         }
 103
 104         free(buf);
 105
 106         return (val);
 107 }