strtod.c revision 104834
1/* Implementation of strtod for systems with atof. 2 Copyright (C) 1991, 1995, 2002 Free Software Foundation, Inc. 3 4This file is part of the libiberty library. This library is free 5software; you can redistribute it and/or modify it under the 6terms of the GNU General Public License as published by the 7Free Software Foundation; either version 2, or (at your option) 8any later version. 9 10This library is distributed in the hope that it will be useful, 11but WITHOUT ANY WARRANTY; without even the implied warranty of 12MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13GNU General Public License for more details. 14 15You should have received a copy of the GNU General Public License 16along with GNU CC; see the file COPYING. If not, write to 17the Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 18 19As a special exception, if you link this library with files 20compiled with a GNU compiler to produce an executable, this does not cause 21the resulting executable to be covered by the GNU General Public License. 22This exception does not however invalidate any other reasons why 23the executable file might be covered by the GNU General Public License. */ 24 25/* 26 27@deftypefn Supplemental double strtod (const char *@var{string}, char **@var{endptr}) 28 29This ISO C function converts the initial portion of @var{string} to a 30@code{double}. If @var{endptr} is not @code{NULL}, a pointer to the 31character after the last character used in the conversion is stored in 32the location referenced by @var{endptr}. If no conversion is 33performed, zero is returned and the value of @var{string} is stored in 34the location referenced by @var{endptr}. 35 36@end deftypefn 37 38*/ 39 40#include "ansidecl.h" 41#include "safe-ctype.h" 42 43extern double atof (); 44 45/* Disclaimer: this is currently just used by CHILL in GDB and therefore 46 has not been tested well. It may have been tested for nothing except 47 that it compiles. */ 48 49double 50strtod (str, ptr) 51 char *str; 52 char **ptr; 53{ 54 char *p; 55 56 if (ptr == (char **)0) 57 return atof (str); 58 59 p = str; 60 61 while (ISSPACE (*p)) 62 ++p; 63 64 if (*p == '+' || *p == '-') 65 ++p; 66 67 /* INF or INFINITY. */ 68 if ((p[0] == 'i' || p[0] == 'I') 69 && (p[1] == 'n' || p[1] == 'N') 70 && (p[2] == 'f' || p[2] == 'F')) 71 { 72 if ((p[3] == 'i' || p[3] == 'I') 73 && (p[4] == 'n' || p[4] == 'N') 74 && (p[5] == 'i' || p[5] == 'I') 75 && (p[6] == 't' || p[6] == 'T') 76 && (p[7] == 'y' || p[7] == 'Y')) 77 { 78 *ptr = p + 8; 79 return atof (str); 80 } 81 else 82 { 83 *ptr = p + 3; 84 return atof (str); 85 } 86 } 87 88 /* NAN or NAN(foo). */ 89 if ((p[0] == 'n' || p[0] == 'N') 90 && (p[1] == 'a' || p[1] == 'A') 91 && (p[2] == 'n' || p[2] == 'N')) 92 { 93 p += 3; 94 if (*p == '(') 95 { 96 ++p; 97 while (*p != '\0' && *p != ')') 98 ++p; 99 if (*p == ')') 100 ++p; 101 } 102 *ptr = p; 103 return atof (str); 104 } 105 106 /* digits, with 0 or 1 periods in it. */ 107 if (ISDIGIT (*p) || *p == '.') 108 { 109 int got_dot = 0; 110 while (ISDIGIT (*p) || (!got_dot && *p == '.')) 111 { 112 if (*p == '.') 113 got_dot = 1; 114 ++p; 115 } 116 117 /* Exponent. */ 118 if (*p == 'e' || *p == 'E') 119 { 120 int i; 121 i = 1; 122 if (p[i] == '+' || p[i] == '-') 123 ++i; 124 if (ISDIGIT (p[i])) 125 { 126 while (ISDIGIT (p[i])) 127 ++i; 128 *ptr = p + i; 129 return atof (str); 130 } 131 } 132 *ptr = p; 133 return atof (str); 134 } 135 /* Didn't find any digits. Doesn't look like a number. */ 136 *ptr = str; 137 return 0.0; 138} 139