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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision b4c8cba4b4405f5abf394ffc8286a1dd13732a8f authored by Anthony Baxter on 23 October 2006, 15:38:59 UTC, committed by Anthony Baxter on 23 October 2006, 15:38:59 UTC 
set svn:ignore. anal retentiveness, makes it easier to spot actual problems
1 parent 9f839d5
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Tip revision: b4c8cba4b4405f5abf394ffc8286a1dd13732a8f authored by Anthony Baxter on 23 October 2006, 15:38:59 UTC
set svn:ignore. anal retentiveness, makes it easier to spot actual problems
Tip revision: b4c8cba
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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