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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision 413a49145e35c7a2d3a7de27c5a1828449c9b2e5 authored by Benjamin Peterson on 02 March 2019, 18:17:42 UTC, committed by Benjamin Peterson on 02 March 2019, 18:17:42 UTC 
Set version to 2.7.16 final.
1 parent 10b8873
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Tip revision: 413a49145e35c7a2d3a7de27c5a1828449c9b2e5 authored by Benjamin Peterson on 02 March 2019, 18:17:42 UTC
Set version to 2.7.16 final.
Tip revision: 413a491
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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