231 lines
7.7 KiB
C
231 lines
7.7 KiB
C
/*
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FUNCTION
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<<wcstod>>, <<wcstof>>---wide char string to double or float
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INDEX
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wcstod
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INDEX
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_wcstod_r
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INDEX
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wcstof
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INDEX
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_wcstof_r
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ANSI_SYNOPSIS
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#include <stdlib.h>
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double wcstod(const wchar_t *<[str]>, wchar_t **<[tail]>);
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float wcstof(const wchar_t *<[str]>, wchar_t **<[tail]>);
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double _wcstod_r(void *<[reent]>,
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const wchar_t *<[str]>, wchar_t **<[tail]>);
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float _wcstof_r(void *<[reent]>,
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const wchar_t *<[str]>, wchar_t **<[tail]>);
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TRAD_SYNOPSIS
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#include <stdlib.h>
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double wcstod(<[str]>,<[tail]>)
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wchar_t *<[str]>;
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wchar_t **<[tail]>;
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float wcstof(<[str]>,<[tail]>)
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wchar_t *<[str]>;
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wchar_t **<[tail]>;
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double _wcstod_r(<[reent]>,<[str]>,<[tail]>)
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wchar_t *<[reent]>;
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wchar_t *<[str]>;
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wchar_t **<[tail]>;
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float _wcstof_r(<[reent]>,<[str]>,<[tail]>)
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wchar_t *<[reent]>;
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wchar_t *<[str]>;
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wchar_t **<[tail]>;
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DESCRIPTION
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The function <<wcstod>> parses the wide character string <[str]>,
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producing a substring which can be converted to a double
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value. The substring converted is the longest initial
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subsequence of <[str]>, beginning with the first
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non-whitespace character, that has one of these formats:
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.[+|-]<[digits]>[.[<[digits]>]][(e|E)[+|-]<[digits]>]
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.[+|-].<[digits]>[(e|E)[+|-]<[digits]>]
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.[+|-](i|I)(n|N)(f|F)[(i|I)(n|N)(i|I)(t|T)(y|Y)]
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.[+|-](n|N)(a|A)(n|N)[<(>[<[hexdigits]>]<)>]
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.[+|-]0(x|X)<[hexdigits]>[.[<[hexdigits]>]][(p|P)[+|-]<[digits]>]
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.[+|-]0(x|X).<[hexdigits]>[(p|P)[+|-]<[digits]>]
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The substring contains no characters if <[str]> is empty, consists
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entirely of whitespace, or if the first non-whitespace
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character is something other than <<+>>, <<->>, <<.>>, or a
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digit, and cannot be parsed as infinity or NaN. If the platform
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does not support NaN, then NaN is treated as an empty substring.
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If the substring is empty, no conversion is done, and
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the value of <[str]> is stored in <<*<[tail]>>>. Otherwise,
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the substring is converted, and a pointer to the final string
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(which will contain at least the terminating null character of
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<[str]>) is stored in <<*<[tail]>>>. If you want no
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assignment to <<*<[tail]>>>, pass a null pointer as <[tail]>.
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<<wcstof>> is identical to <<wcstod>> except for its return type.
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This implementation returns the nearest machine number to the
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input decimal string. Ties are broken by using the IEEE
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round-even rule. However, <<wcstof>> is currently subject to
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double rounding errors.
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The alternate functions <<_wcstod_r>> and <<_wcstof_r>> are
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reentrant versions of <<wcstod>> and <<wcstof>>, respectively.
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The extra argument <[reent]> is a pointer to a reentrancy structure.
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RETURNS
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Return the converted substring value, if any. If
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no conversion could be performed, 0 is returned. If the
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correct value is out of the range of representable values,
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plus or minus <<HUGE_VAL>> is returned, and <<ERANGE>> is
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stored in errno. If the correct value would cause underflow, 0
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is returned and <<ERANGE>> is stored in errno.
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Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
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<<lseek>>, <<read>>, <<sbrk>>, <<write>>.
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*/
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/*-
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* Copyright (c) 2002 Tim J. Robbins
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <_ansi.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <wchar.h>
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#include <wctype.h>
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#include <locale.h>
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#include <math.h>
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double
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_DEFUN (_wcstod_r, (ptr, nptr, endptr),
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struct _reent *ptr _AND
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_CONST wchar_t *nptr _AND
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wchar_t **endptr)
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{
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static const mbstate_t initial;
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mbstate_t mbs;
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double val;
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char *buf, *end;
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const wchar_t *wcp;
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size_t len;
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while (iswspace(*nptr))
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nptr++;
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/*
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* Convert the supplied numeric wide char. string to multibyte.
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*
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* We could attempt to find the end of the numeric portion of the
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* wide char. string to avoid converting unneeded characters but
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* choose not to bother; optimising the uncommon case where
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* the input string contains a lot of text after the number
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* duplicates a lot of strtod()'s functionality and slows down the
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* most common cases.
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*/
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wcp = nptr;
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mbs = initial;
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if ((len = _wcsrtombs_r(ptr, NULL, &wcp, 0, &mbs)) == (size_t)-1) {
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if (endptr != NULL)
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*endptr = (wchar_t *)nptr;
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return (0.0);
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}
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if ((buf = _malloc_r(ptr, len + 1)) == NULL)
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return (0.0);
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mbs = initial;
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_wcsrtombs_r(ptr, buf, &wcp, len + 1, &mbs);
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/* Let strtod() do most of the work for us. */
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val = _strtod_r(ptr, buf, &end);
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/*
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* We only know where the number ended in the _multibyte_
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* representation of the string. If the caller wants to know
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* where it ended, count multibyte characters to find the
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* corresponding position in the wide char string.
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*/
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if (endptr != NULL) {
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/* The only valid multibyte char in a float converted by
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strtod/wcstod is the radix char. What we do here is,
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figure out if the radix char was in the valid leading
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float sequence in the incoming string. If so, the
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multibyte float string is strlen(radix char) - 1 bytes
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longer than the incoming wide char string has characters.
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To fix endptr, reposition end as if the radix char was
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just one byte long. The resulting difference (end - buf)
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is then equivalent to the number of valid wide characters
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in the input string. */
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len = strlen (_localeconv_r (ptr)->decimal_point);
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if (len > 1) {
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char *d = strstr (buf,
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_localeconv_r (ptr)->decimal_point);
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if (d && d < end)
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end -= len - 1;
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}
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*endptr = (wchar_t *)nptr + (end - buf);
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}
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_free_r(ptr, buf);
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return (val);
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}
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float
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_DEFUN (_wcstof_r, (ptr, nptr, endptr),
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struct _reent *ptr _AND
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_CONST wchar_t *nptr _AND
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wchar_t **endptr)
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{
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double retval = _wcstod_r (ptr, nptr, endptr);
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if (isnan (retval))
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return nanf (NULL);
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return (float)retval;
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}
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#ifndef _REENT_ONLY
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double
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_DEFUN (wcstod, (nptr, endptr),
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_CONST wchar_t *nptr _AND wchar_t **endptr)
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{
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return _wcstod_r (_REENT, nptr, endptr);
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}
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float
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_DEFUN (wcstof, (nptr, endptr),
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_CONST wchar_t *nptr _AND
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wchar_t **endptr)
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{
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double retval = _wcstod_r (_REENT, nptr, endptr);
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if (isnan (retval))
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return nanf (NULL);
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return (float)retval;
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}
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#endif
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