/* DEC	*ConvDoubleToDecimal( x, f)
 *
 * ARGUMENT
 *	DEC	*x;
 *	double	f;
 *
 * DESCRIPTION
 *	Converts a double to a DEC with	maximum	implied	decimal.  Uses
 * eTwoTo32 (2^32), eTwoTo63 (2^63), and ergGMPowersOfTenDouble
 *  (powers of ten), all global	double variables.
 *
 * SIDE	EFFECTS
 *	None.
 *
 * RETURNS
 *	The DEC	if the conversion is successful, and GM_NULL otherwise.
 *
 * POSSIBLE ERROR CODES
 *
 *	GM_NOMEMORY
 *	GM_CNVRE
 *
 * AUTHOR
 *   Jared Levy		Feb. 9,	1987
 *   Copyright (C) 1987-1990 Greenleaf Software	Inc.  All rights reserved.
 *
 * MODIFICATIONS
 *
 */

#include <stdio.h>
#include "gm.h"
#include "gmsystem.h"
#include "math.h"

DEC	*ConvDoubleToDecimal( x, f)
DEC	*x;
double	f;

{
	int	nid;
	mbool	wfIsNeg=FALSE;
	double	g;

	_MacStart(GM_DFTOD);
	_MacOutVarD(x);

/* take	absolute value of negative values */
	if (f<0.0) {
		wfIsNeg	= TRUE;
		f = -f;
		}

/* f = 0 */
	if (f == 0.0)  {
		_MacDZero(x);
		_MacRet(x);
		}

/* overflow & underflow	(MAXID = 18, MINID = 0)	*/
	if ((f>=eTwoTo63) || (f<.5e-18))  {
		if (x)
			_MacDZero(x);
		_MacErr(GM_CNVRE);
		_MacRet(GM_NULL);
		}

/* take	absolute value of negative values */
	if (f<0.0) {
		wfIsNeg	= TRUE;
		f = -f;
		}

	_MacDZero(x);

/* calculate implied decimal of	DEC */
	g = eTwoTo63/f;
	nid = 0;
	while ((nid <= 17) && (ergGMPowersOfTenDouble[nid+1] <=	g))
		nid++;

/* adjust by power of 10 */
	f = f *	ergGMPowersOfTenDouble[nid];

/* add .5 to round rather than truncate	*/
	f+= 0.5;

/* change float	to 64 bit integer */
	if (f >= eTwoTo32 - 1)	{
#ifdef ZORTECH
		if ( (f	/ eTwoTo32) > eTwoTo31 ) {
		    x->ls.lsl[1] = (unsigned long) ((f / eTwoTo32) - eTwoTo31 );
		    x->ls.lsl[1] += (unsigned long) eTwoTo31;
		} else
		    x->ls.lsl[1] = (unsigned long) (f /	eTwoTo32);
#else
		x->ls.lsl[1] = (unsigned long) (f / eTwoTo32);
#endif
		g = (double) x->ls.lsl[1];
		f-= g *	eTwoTo32;
		while (f<0.0)  {
			x->ls.lsl[1]--;
			f+= eTwoTo32;
			}
		while (f>= eTwoTo32)  {
			x->ls.lsl[1]++;
			f-= eTwoTo32;
			}
		}
	else
		x->ls.lsl[1] = 0;

#ifdef ZORTECH
       if ( f >	eTwoTo31 ) {
	   x->ls.lsl[0]	= f - eTwoTo31;
	   x->ls.lsl[0]	+= (unsigned long) eTwoTo31;
       } else
	   x->ls.lsl[0]	= (unsigned long) f;
#else
	x->ls.lsl[0] = (unsigned long) f;
#endif
	x->ls.lid = nid;
	x->dc.msd = 0;	/* msd can't be	set either */

	if (wfIsNeg) {
		_MacDChgs(x);
	}

	_MacRet(x);
}