/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */
#include "curses.ext"
#include <ctype.h>
#include <strings.h>

#define min(a,b)	(a < b ? a : b)
#define max(a,b)	(a > b ? a : b)

/*
 * This routine writes win1 on win2 non-destructively.
 */
void
overlay(win1, win2)
        reg WINDOW	*win1, *win2;
{

	reg char	*sp, *end;
	reg int		x, y, endy, endx, starty, startx;
	reg int 	y1,y2;

# ifdef DEBUG
	fprintf(outf, "OVERLAY(%0.2o, %0.2o);\n", win1, win2);
# endif
	starty = max(win1->_begy, win2->_begy);
	startx = max(win1->_begx, win2->_begx);
	endy = min(win1->_maxy + win1->_begy, win2->_maxy + win2->_begx);
	endx = min(win1->_maxx + win1->_begx, win2->_maxx + win2->_begx);
# ifdef DEBUG
	fprintf(outf, "OVERLAY:from (%d,%d) to (%d,%d)\n", starty, startx, endy, endx);
# endif
	if (starty >= endy || startx >= endx)
		return;
	x = endx - startx;
	for (y = starty; y < endy; y++) {
		bcopy(&win1->_y[y - win1->_begy][startx - win1->_begx],
		      &win2->_y[y - win2->_begy][startx - win2->_begx], x);
		touchline(win2, y, startx - win2->_begx, endx - win2->_begx);
	}
	y1 = starty - win1->_begy;
	y2 = starty - win2->_begy;
	for (y = starty; y < endy; y++, y1++, y2++) {
		end = &win1->_y[y1][endx - win1->_begx];
		x = startx - win2->_begx;
		for (sp = &win1->_y[y1][startx - win1->_begx]; sp < end; sp++) {
			if (!isspace(*sp))
				mvwaddch(win2, y2, x, *sp);
			x++;
		}
	}
}
