1  /* Implementation of strtod for systems with atof.
       2     Copyright (C) 1991-2023 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, 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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  /*
      26  
      27  @deftypefn Supplemental double strtod (const char *@var{string}, @
      28    char **@var{endptr})
      29  
      30  This ISO C function converts the initial portion of @var{string} to a
      31  @code{double}.  If @var{endptr} is not @code{NULL}, a pointer to the
      32  character after the last character used in the conversion is stored in
      33  the location referenced by @var{endptr}.  If no conversion is
      34  performed, zero is returned and the value of @var{string} is stored in
      35  the location referenced by @var{endptr}.
      36  
      37  @end deftypefn
      38  
      39  */
      40  
      41  #include "ansidecl.h"
      42  #include "safe-ctype.h"
      43  
      44  extern double atof (const char *);
      45  
      46  /* Disclaimer: this is currently just used by CHILL in GDB and therefore
      47     has not been tested well.  It may have been tested for nothing except
      48     that it compiles.  */
      49  
      50  double
      51  strtod (char *str, char **ptr)
      52  {
      53    char *p;
      54  
      55    if (ptr == (char **)0)
      56      return atof (str);
      57    
      58    p = str;
      59    
      60    while (ISSPACE (*p))
      61      ++p;
      62    
      63    if (*p == '+' || *p == '-')
      64      ++p;
      65  
      66    /* INF or INFINITY.  */
      67    if ((p[0] == 'i' || p[0] == 'I')
      68        && (p[1] == 'n' || p[1] == 'N')
      69        && (p[2] == 'f' || p[2] == 'F'))
      70      {
      71        if ((p[3] == 'i' || p[3] == 'I')
      72  	  && (p[4] == 'n' || p[4] == 'N')
      73  	  && (p[5] == 'i' || p[5] == 'I')
      74  	  && (p[6] == 't' || p[6] == 'T')
      75  	  && (p[7] == 'y' || p[7] == 'Y'))
      76  	{
      77  	  *ptr = p + 8;
      78  	  return atof (str);
      79  	}
      80        else
      81  	{
      82  	  *ptr = p + 3;
      83  	  return atof (str);
      84  	}
      85      }
      86  
      87    /* NAN or NAN(foo).  */
      88    if ((p[0] == 'n' || p[0] == 'N')
      89        && (p[1] == 'a' || p[1] == 'A')
      90        && (p[2] == 'n' || p[2] == 'N'))
      91      {
      92        p += 3;
      93        if (*p == '(')
      94  	{
      95  	  ++p;
      96  	  while (*p != '\0' && *p != ')')
      97  	    ++p;
      98  	  if (*p == ')')
      99  	    ++p;
     100  	}
     101        *ptr = p;
     102        return atof (str);
     103      }
     104  
     105    /* digits, with 0 or 1 periods in it.  */
     106    if (ISDIGIT (*p) || *p == '.')
     107      {
     108        int got_dot = 0;
     109        while (ISDIGIT (*p) || (!got_dot && *p == '.'))
     110  	{
     111  	  if (*p == '.')
     112  	    got_dot = 1;
     113  	  ++p;
     114  	}
     115  
     116        /* Exponent.  */
     117        if (*p == 'e' || *p == 'E')
     118  	{
     119  	  int i;
     120  	  i = 1;
     121  	  if (p[i] == '+' || p[i] == '-')
     122  	    ++i;
     123  	  if (ISDIGIT (p[i]))
     124  	    {
     125  	      while (ISDIGIT (p[i]))
     126  		++i;
     127  	      *ptr = p + i;
     128  	      return atof (str);
     129  	    }
     130  	}
     131        *ptr = p;
     132        return atof (str);
     133      }
     134    /* Didn't find any digits.  Doesn't look like a number.  */
     135    *ptr = str;
     136    return 0.0;
     137  }