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


/*
 *      Copyright (c) 1997, by Sun Microsystems, Inc.
 *      All rights reserved.
 */

/*LINTLIBRARY*/

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

/*
 *      Shift right an interval of characters
 */

int
_mbinsshift(WINDOW *win, int len)
{
        int     x, y, maxx,  mv;
        chtype  *wcp, *wp, *ep;

        y = win->_cury;
        x = win->_curx;
        maxx = win->_maxx;
        wcp  = win->_y[y];

        /* ASSERT(!ISCBIT(wcp[x])); */

        /* shift up to a whole character */
        if (_scrmax > 1) {
                wp = wcp + maxx - 1;
                if (ISMBIT(*wp)) {
                        reg chtype      rb;

                        for (; wp >= wcp; --wp)
                                if (!ISCBIT(*wp))
                                        break;
                        if (wp < wcp)
                                return (ERR);
                        rb = RBYTE(*wp);
                        if ((wp + _curs_scrwidth[TYPE(rb)]) > (wcp + maxx))
                                /*LINTED*/
                                maxx = (int)(wp - wcp);
                        }
                }

        /* see if any data need to move */
        if ((mv = maxx - (x+len)) <= 0)
                return (OK);

        /* the end of the moved interval must be whole */
        if (ISCBIT(wcp[x + mv]))
                (void) _mbclrch(win, y, x + mv - 1);

        /* move data */
        ep = wcp + x + len;
        for (wp = wcp + maxx - 1; wp >= ep; --wp)
                *wp = *(wp - len);

        /* clear a possible partial multibyte character */
        if (ISMBIT(*wp))
                for (ep = wp; ep >= wcp; --ep) {
                        mv = (int)(ISCBIT(*ep));
                        *ep = win->_bkgd;
                        if (!mv)
                                break;
                }

        /* update the change structure */
        if (x < win->_firstch[y])
                /*LINTED*/
                win->_firstch[y] = (short)x;
        win->_lastch[y] = maxx - 1;

        return (OK);
}