ack/lang/pc/libpc/wrf.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.h"

#define assert(x) /* nothing */

#if __STDC__
#include <float.h>
#define HUGE_DIG DBL_MAX_10_EXP /* log10(maxreal) */
#else
#define HUGE_DIG 400 /* log10(maxreal) */
#endif
#define PREC_DIG 80 /* the maximum digits returned by _fcvt() */
#define FILL_CHAR '0' /* char printed if all of _fcvt() used */
#define BUFSIZE HUGE_DIG + PREC_DIG + 3

void _wrf(int n, int w, double r, struct file* f)
{
	char *p, *b;
	int s, d;
	char buf[BUFSIZE];

	if (n < 0 || w < 0)
		_trp(EWIDTH);
	p = buf;
	if (n > PREC_DIG)
		n = PREC_DIG;
	b = _fcvt(r, n, &d, &s);
	assert(abs(d) <= HUGE_DIG);
	if (s)
		*p++ = '-';
	if (d <= 0)
		*p++ = '0';
	else
		do
			*p++ = (*b ? *b++ : FILL_CHAR);
		while (--d > 0);
	if (n > 0)
		*p++ = '.';
	while (++d <= 0)
	{
		if (--n < 0)
			break;
		*p++ = '0';
	}
	while (--n >= 0)
	{
		*p++ = (*b ? *b++ : FILL_CHAR);
		assert(p <= buf + BUFSIZE);
	}
	_wstrin(w, (int)(p - buf), buf, f);
}