/* void	AddDaysToDate360( m2, d2, y2, m1, d1, y1, ndays	)
 *
 * ARGUMENTS
 *	int  m1,  d1,  y1	- Specify a base date.
 *	int *m2, *d2, *y2	- Specify a date to be calculated
 *	int ndays		- Number of days (+ or -) to be	added to base
 *
 * DESCRIPTION
 *  A signed number of days (ndays) is added to	the base date to form a
 *  second date	which is transferred to	the variables m2,d2,y2.	 If any	of
 *  the	arguments are NULL on input, an	error results.
 *
 *  Years < 100	are taken to be	in 20th	century.
 *
 *  All	years are considered to	have 12	equal months of	30 days	each for
 *  a total of 360 days.
 *
 * SIDE	EFFECTS
 *	Changes	d2, m2,	y2.
 *
 * RETURNS
 *	None.
 *
 * POSSIBLE ERROR CODES
 *
 *	GM_ARGVAL
 *	GM_NULLPOINTER
 *
 * AUTHOR
 *  Don	Killen	 03-Feb-1988  16:27:32
 *   Copyright (C) 1988-1990 Greenleaf Software	Inc.  All rights reserved.
 *
 * MODIFICATIONS
 *
 *
 */

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

void	AddDaysToDate360(m2,d2,y2,m1,d1,y1,ndays)
int	m1,*m2,d1,*d2,y1,*y2,ndays;
{

	long	day;

	_MacStart(GM_ADATE360);

	if (d2==NULL||m2==NULL||y2==NULL)  {
		_MacErr(GM_NULLPOINTER);
		_MacRetV;
	}

	if ( m1<1 || m1>12 || d1<1 || d1>31 || y1<1 || y1>9999 )  {
		_MacErr(GM_ARGVAL);
		_MacRetV;
	}
	day = (long) y1	* 360L + (long)	( (m1-1)*30 + (d1-1) + ndays);
	/* computes days from Jan 1, Year 0 */

	if (day<0L)  {			/* no negative years */
		_MacErr(GM_ARGVAL);
		_MacRetV;
	}

	/* changes to m2/d2/y2 */
	*y2 = (int) (day / 360L);
	day = day % 360L;

	*m2 = (int) (day) / 30 + 1;

	*d2 = (int) (day) % 30 + 1;

	_MacRetV;
}