/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 1997 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1988 AT&T */
/*        All Rights Reserved   */

/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

/*LINTLIBRARY*/

#include        <sys/types.h>
#include        "curses_inc.h"

/*
 * This routine writes Srcwin on Dstwin.
 * Only the overlapping region is copied.
 */

int
_overlap(WINDOW *Srcwin, WINDOW *Dstwin, int Overlay)
{
        int     sby, sbx, sey, sex, dby, dbx, dey, dex,
                top, bottom, left, right;

#ifdef  DEBUG
        if (outf)
                fprintf(outf, "OVERWRITE(0%o, 0%o);\n", Srcwin, Dstwin);
#endif  /* DEBUG */

        sby = Srcwin->_begy;    dby = Dstwin->_begy;
        sbx = Srcwin->_begx;    dbx = Dstwin->_begx;
        sey = sby + Srcwin->_maxy;      dey = dby + Dstwin->_maxy;
        sex = sbx + Srcwin->_maxx;      dex = dbx + Dstwin->_maxx;

        if (sey < dby || sby > dey || sex < dbx || sbx > dex)
                return (ERR);

        top = _MAX(sby, dby);   bottom = _MIN(sey, dey);
        left = _MAX(sbx, dbx);  right = _MIN(sex, dex);

        sby = top - sby;                sbx = left - sbx;
        dey = bottom - dby - 1; dex = right - dbx - 1;
        dby = top - dby;                dbx = left - dbx;

        return (copywin(Srcwin, Dstwin, sby, sbx, dby, dbx, dey, dex, Overlay));
}