/*
 * 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"

/*
 *      Make a  derived window of an existing window. The two windows
 *      share the same character image.
 *              orig:   the original window
 *              nl, nc: numbers of lines and columns
 *              by, bx: coordinates for upper-left corner of the derived
 *                      window in the coord system of the parent window.
 */

WINDOW  *
derwin(WINDOW *orig, int num_lines, int nc, int by, int bx)
{
        int     y;
        WINDOW  *win = (WINDOW *) NULL, *par;
        chtype  **w_y, **o_y;
#ifdef  _VR3_COMPAT_CODE
        _ochtype        **w_y16, **o_y16;
#endif  /* _VR3_COMPAT_CODE */

        /* make sure window fits inside the original one */
        if (by < 0 || (by + num_lines) > orig->_maxy || bx < 0 ||
            (bx + nc) > orig->_maxx)
                goto done;
        if (nc == 0)
                nc = orig->_maxx - bx;
        if (num_lines == 0)
                num_lines = orig->_maxy - by;

        /* Create the window skeleton */
        if ((win = _makenew(num_lines, nc, by + orig->_begy,
            bx + orig->_begx)) == NULL)
                goto done;

        /* inheritance */
        /*LINTED*/
        win->_parx = (short) bx;
        /*LINTED*/
        win->_pary = (short) by;
        win->_bkgd = orig->_bkgd;
        win->_attrs = orig->_attrs;
        w_y = win->_y;
        o_y = orig->_y;

#ifdef  _VR3_COMPAT_CODE
        if (_y16update) {
                int     hby = by;

                w_y16 = win ->_y16;
                o_y16 = orig->_y16;

                for (y = 0; y < num_lines; y++, hby++)
                        w_y16[y] = o_y16[hby] + bx;
        }
#endif  /* _VR3_COMPAT_CODE */

        for (y = 0; y < num_lines; y++, by++)
                w_y[y] = o_y[by] + bx;

        win->_yoffset = orig->_yoffset;

        /* update descendant number of ancestors */
        win->_parent = orig;
        for (par = win->_parent; par != NULL; par = par->_parent)
                par->_ndescs += 1;

done:
        return (win);
}