summaryrefslogtreecommitdiff
path: root/lib/xstrtod.c
blob: f6edefccebc6d0071634fc7813ca5a18c1eead12 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
/* xstrtod.c - error-checking interface to strtod
   Copyright (C) 1996 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* Written by Jim Meyering.  */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef STDC_HEADERS
#include <stdlib.h>
#else
double strtod ();
#endif

#include <errno.h>
#include <stdio.h>
#include <limits.h>
#include "xstrtod.h"

/* An interface to strtod that encapsulates all the error checking
   one should usually perform.  Like strtod, but upon successful
   conversion put the result in *RESULT and return zero.  Return
   non-zero and don't modify *RESULT upon any failure.  */

int
xstrtod (str, ptr, result)
     const char *str;
     const char **ptr;
     double *result;
{
  double val;
  char *terminator;
  int fail;

  fail = 0;
  errno = 0;
  val = strtod (str, &terminator);

  /* Having a non-zero terminator is an error only when PTR is NULL. */
  if (terminator == str || (ptr == NULL && *terminator != '\0'))
    fail = 1;
  else
    {
      /* Allow underflow (in which case strtod returns zero),
	 but flag overflow as an error. */
      if (val != 0.0 && errno == ERANGE)
	fail = 1;
    }

  if (ptr != NULL)
    *ptr = terminator;

  *result = val;
  return fail;
}