1 

     2 /* Just in case you haven't got an atof() around...

     3    This one doesn't check for bad syntax or overflow,

     4    and is slow and inaccurate.

     5    But it's good enough for the occasional string literal... */

     6 

     7 #include "pyconfig.h"

     8 

     9 #include <ctype.h>

    10 

    11 double atof(char *s)

    12 {

    13 	double a = 0.0;

    14 	int e = 0;

    15 	int c;

    16 	while ((c = *s++) != '\0' && isdigit(c)) {

    17 		a = a*10.0 + (c - '0');

    18 	}

    19 	if (c == '.') {

    20 		while ((c = *s++) != '\0' && isdigit(c)) {

    21 			a = a*10.0 + (c - '0');

    22 			e = e-1;

    23 		}

    24 	}

    25 	if (c == 'e' || c == 'E') {

    26 		int sign = 1;

    27 		int i = 0;

    28 		c = *s++;

    29 		if (c == '+')

    30 			c = *s++;

    31 		else if (c == '-') {

    32 			c = *s++;

    33 			sign = -1;

    34 		}

    35 		while (isdigit(c)) {

    36 			i = i*10 + (c - '0');

    37 			c = *s++;

    38 		}

    39 		e += i*sign;

    40 	}

    41 	while (e > 0) {

    42 		a *= 10.0;

    43 		e--;

    44 	}

    45 	while (e < 0) {

    46 		a *= 0.1;

    47 		e++;

    48 	}

    49 	return a;

    50 }