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v0.8.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision 6a66a68fe6132418ad6aba5162871f0dcd3651ad authored by cvs2svn on 18 July 2003, 17:45:33 UTC, committed by cvs2svn on 18 July 2003, 17:45:33 UTC 
This commit was manufactured by cvs2svn to create tag 'r23c1'.
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Tip revision: 6a66a68fe6132418ad6aba5162871f0dcd3651ad authored by cvs2svn on 18 July 2003, 17:45:33 UTC
This commit was manufactured by cvs2svn to create tag 'r23c1'.
Tip revision: 6a66a68
atof.c 

/* Just in case you haven't got an atof() around...
   This one doesn't check for bad syntax or overflow,
   and is slow and inaccurate.
   But it's good enough for the occasional string literal... */

#include "pyconfig.h"

#include <ctype.h>

double atof(char *s)
{
	double a = 0.0;
	int e = 0;
	int c;
	while ((c = *s++) != '\0' && isdigit(c)) {
		a = a*10.0 + (c - '0');
	}
	if (c == '.') {
		while ((c = *s++) != '\0' && isdigit(c)) {
			a = a*10.0 + (c - '0');
			e = e-1;
		}
	}
	if (c == 'e' || c == 'E') {
		int sign = 1;
		int i = 0;
		c = *s++;
		if (c == '+')
			c = *s++;
		else if (c == '-') {
			c = *s++;
			sign = -1;
		}
		while (isdigit(c)) {
			i = i*10 + (c - '0');
			c = *s++;
		}
		e += i*sign;
	}
	while (e > 0) {
		a *= 10.0;
		e--;
	}
	while (e < 0) {
		a *= 0.1;
		e++;
	}
	return a;
}
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