ack/lang/pc/libpc/rdr.c
2018-06-17 16:11:29 +02:00

86 lines
1.3 KiB
C

/* $Id$ */
/*
* (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
*
* This product is part of the Amsterdam Compiler Kit.
*
* Permission to use, sell, duplicate or disclose this software must be
* obtained in writing. Requests for such permissions may be sent to
*
* Dr. Andrew S. Tanenbaum
* Wiskundig Seminarium
* Vrije Universiteit
* Postbox 7161
* 1007 MC Amsterdam
* The Netherlands
*
*/
/* Author: J.W. Stevenson */
#include <pc_file.h>
#define BIG 1e17
extern _rf();
extern _incpt();
extern _skipsp();
extern int _getsig();
extern int _getint();
extern int _fstdig();
extern int _nxtdig();
static double r;
static int pow10;
static dig(ch) int ch;
{
if (r > BIG)
pow10++;
else
r = r * 10.0 + ch;
}
double _rdr(f) struct file* f;
{
int i;
double e;
int is_signed, ch;
r = 0;
pow10 = 0;
_rf(f);
_skipsp(f);
is_signed = _getsig(f);
ch = _fstdig(f);
do
dig(ch);
while ((ch = _nxtdig(f)) >= 0);
if (*f->ptr == '.')
{
_incpt(f);
ch = _fstdig(f);
do
{
dig(ch);
pow10--;
} while ((ch = _nxtdig(f)) >= 0);
}
if ((*f->ptr == 'e') || (*f->ptr == 'E'))
{
_incpt(f);
pow10 += _getint(f);
}
if ((i = pow10) < 0)
i = -i;
e = 1.0;
while (--i >= 0)
e *= 10.0;
if (pow10 < 0)
r /= e;
else
r *= e;
return (is_signed ? -r : r);
}