1/* error-checking interface to strtod-like functions
2
3   Copyright (C) 1996, 1999-2000, 2003-2006, 2009-2010 Free Software
4   Foundation, Inc.
5
6   This program is free software: you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 3 of the License, or
9   (at your option) any later version.
10
11   This program is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
18
19/* Written by Jim Meyering.  */
20
21#include <config.h>
22
23#include "xstrtod.h"
24
25#include <errno.h>
26#include <limits.h>
27#include <stdio.h>
28
29#if LONG
30# define XSTRTOD xstrtold
31# define DOUBLE long double
32#else
33# define XSTRTOD xstrtod
34# define DOUBLE double
35#endif
36
37/* An interface to a string-to-floating-point conversion function that
38   encapsulates all the error checking one should usually perform.
39   Like strtod/strtold, but upon successful
40   conversion put the result in *RESULT and return true.  Return
41   false and don't modify *RESULT upon any failure.  CONVERT
42   specifies the conversion function, e.g., strtod itself.  */
43
44bool
45XSTRTOD (char const *str, char const **ptr, DOUBLE *result,
46         DOUBLE (*convert) (char const *, char **))
47{
48  DOUBLE val;
49  char *terminator;
50  bool ok = true;
51
52  errno = 0;
53  val = convert (str, &terminator);
54
55  /* Having a non-zero terminator is an error only when PTR is NULL. */
56  if (terminator == str || (ptr == NULL && *terminator != '\0'))
57    ok = false;
58  else
59    {
60      /* Allow underflow (in which case CONVERT returns zero),
61         but flag overflow as an error. */
62      if (val != 0 && errno == ERANGE)
63        ok = false;
64    }
65
66  if (ptr != NULL)
67    *ptr = terminator;
68
69  *result = val;
70  return ok;
71}
72