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v0.8.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision cb7f6544f09d38eb73f9894426f8cca16b9bf5b1 authored by cvs2svn on 26 March 2002, 13:47:16 UTC, committed by cvs2svn on 26 March 2002, 13:47:16 UTC 
This commit was manufactured by cvs2svn to create tag 'r221c2'.
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Tip revision: cb7f6544f09d38eb73f9894426f8cca16b9bf5b1 authored by cvs2svn on 26 March 2002, 13:47:16 UTC
This commit was manufactured by cvs2svn to create tag 'r221c2'.
Tip revision: cb7f654
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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