libiberty/strtod.c

   1 /* Implementation of strtod for systems with atof.
   2    Copyright (C) 1991, 1995 Free Software Foundation, Inc.
   3
   4 This file is part of the libiberty library.  This library is free
   5 software; you can redistribute it and/or modify it under the
   6 terms of the GNU General Public License as published by the
   7 Free Software Foundation; either version 2, or (at your option)
   8 any later version.
   9
  10 This library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with GNU CC; see the file COPYING.  If not, write to
  17 the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18
  19 As a special exception, if you link this library with files
  20 compiled with a GNU compiler to produce an executable, this does not cause
  21 the resulting executable to be covered by the GNU General Public License.
  22 This exception does not however invalidate any other reasons why
  23 the executable file might be covered by the GNU General Public License. */
  24
  25 #include <ctype.h>
  26
  27 extern double atof ();
  28
  29 /* Disclaimer: this is currently just used by CHILL in GDB and therefore
  30    has not been tested well.  It may have been tested for nothing except
  31    that it compiles.  */
  32
  33 double
  34 strtod (str, ptr)
  35      char *str;
  36      char **ptr;
  37 {
  38   char *p;
  39
  40   if (ptr == (char **)0)
  41     return atof (str);
  42
  43   p = str;
  44
  45   while (isspace (*p))
  46     ++p;
  47
  48   if (*p == '+' || *p == '-')
  49     ++p;
  50
  51   /* INF or INFINITY.  */
  52   if ((p[0] == 'i' || p[0] == 'I')
  53       && (p[1] == 'n' || p[1] == 'N')
  54       && (p[2] == 'f' || p[2] == 'F'))
  55     {
  56       if ((p[3] == 'i' || p[3] == 'I')
  57           && (p[4] == 'n' || p[4] == 'N')
  58           && (p[5] == 'i' || p[5] == 'I')
  59           && (p[6] == 't' || p[6] == 'T')
  60           && (p[7] == 'y' || p[7] == 'Y'))
  61         {
  62           *ptr = p + 7;
  63           return atof (str);
  64         }
  65       else
  66         {
  67           *ptr = p + 3;
  68           return atof (str);
  69         }
  70     }
  71
  72   /* NAN or NAN(foo).  */
  73   if ((p[0] == 'n' || p[0] == 'N')
  74       && (p[1] == 'a' || p[1] == 'A')
  75       && (p[2] == 'n' || p[2] == 'N'))
  76     {
  77       p += 3;
  78       if (*p == '(')
  79         {
  80           ++p;
  81           while (*p != '\0' && *p != ')')
  82             ++p;
  83           if (*p == ')')
  84             ++p;
  85         }
  86       *ptr = p;
  87       return atof (str);
  88     }
  89
  90   /* digits, with 0 or 1 periods in it.  */
  91   if (isdigit (*p) || *p == '.')
  92     {
  93       int got_dot = 0;
  94       while (isdigit (*p) || (!got_dot && *p == '.'))
  95         {
  96           if (*p == '.')
  97             got_dot = 1;
  98           ++p;
  99         }
 100
 101       /* Exponent.  */
 102       if (*p == 'e' || *p == 'E')
 103         {
 104           int i;
 105           i = 1;
 106           if (p[i] == '+' || p[i] == '-')
 107             ++i;
 108           if (isdigit (p[i]))
 109             {
 110               while (isdigit (p[i]))
 111                 ++i;
 112               *ptr = p + i;
 113               return atof (str);
 114             }
 115         }
 116       *ptr = p;
 117       return atof (str);
 118     }
 119   /* Didn't find any digits.  Doesn't look like a number.  */
 120   *ptr = str;
 121   return 0.0;
 122 }