view Python/atof.c @ 51009:27d2fa19084a

Merged revisions 68890 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68890 | mark.dickinson | 2009-01-24 15:27:44 +0000 (Sat, 24 Jan 2009) | 6 lines Issue #4393: fix 3 classes of potential portability problems in longobject.c: - fix some places where counters into ob_digit were declared as int instead of Py_ssize_t - add (twodigit) casts where necessary - fix code in _PyLong_AsByteArray that uses << on negative values ........
author Mark Dickinson <dickinsm@gmail.com>
date Sat, 24 Jan 2009 15:56:57 +0000
parents 2dea40e40d9d
children fd25030223b0
line wrap: on
line source


/* 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;
}