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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>
double
strtod(const char *nptr, char ** endptr)
{
unsigned short negative;
double number;
double 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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