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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision b7f4c2d03af4c7d3960df64b7ae4139520c9fdcf authored by cvs2svn on 30 March 2005, 03:01:43 UTC, committed by cvs2svn on 30 March 2005, 03:01:43 UTC 
This commit was manufactured by cvs2svn to create tag 'r241'.
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Tip revision: b7f4c2d03af4c7d3960df64b7ae4139520c9fdcf authored by cvs2svn on 30 March 2005, 03:01:43 UTC
This commit was manufactured by cvs2svn to create tag 'r241'.
Tip revision: b7f4c2d
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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