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/*
* strtod.c - This file is part of the libc-8086 package for ELKS,
* Copyright (C) 1995, 1996 Nat Friedman <ndf@linux.mit.edu>.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <stdlib.h>
#include <ctype.h>
float strtod(const char *nptr, char **endptr)
{
unsigned short negative;
float number;
float fp_part;
int exponent;
unsigned short exp_negative;
/* advance beyond any leading whitespace */
while (isspace(*nptr))
nptr++;
/* check for optional '+' or '-' */
negative = 0;
if (*nptr == '-') {
negative = 1;
nptr++;
} else if (*nptr == '+')
nptr++;
number = 0;
while (isdigit(*nptr)) {
number = number * 10 + (*nptr - '0');
nptr++;
}
if (*nptr == '.') {
nptr++;
fp_part = 0;
while (isdigit(*nptr)) {
fp_part = fp_part / 10.0 + (*nptr - '0') / 10.0;
nptr++;
}
number += fp_part;
}
if (*nptr == 'e' || *nptr == 'E') {
nptr++;
exp_negative = 0;
if (*nptr == '-') {
exp_negative = 1;
nptr++;
} else if (*nptr == '+')
nptr++;
exponent = 0;
while (isdigit(*nptr)) {
exponent = exponent * 10 + (*nptr - '0');
exponent++;
}
}
while (exponent) {
if (exp_negative)
number /= 10;
else
number *= 10;
exponent--;
}
return (negative ? -number : number);
}
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