/*
 * 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) 1995-1999 by Sun Microsystems, Inc.
 * All rights reserved.
 */

/* LINTLIBRARY */

/*
 * wscrl.c
 *
 * XCurses Library
 *
 * Copyright 1990, 1995 by Mortice Kern Systems Inc.  All rights reserved.
 *
 */

#ifdef M_RCSID
#ifndef lint
static char rcsID[] =
"$Header: /team/ps/sun_xcurses/archive/local_changes/xcurses/src/lib/"
"libxcurses/src/libc/xcurses/rcs/wscrl.c 1.8 1998/06/04 17:52:07 "
"cbates Exp $";
#endif
#endif

#include <private.h>
#include <string.h>

/*
 * For positive n scroll the window up n lines (line i+n becomes i);
 * otherwise scroll the window down n lines.
 */
int
wscrl(WINDOW *w, int n)
{
        int     start, finish, to;

        if (!(w->_flags & W_CAN_SCROLL))
                return (ERR);

        if (n == 0)
                return (OK);

        if (w->_parent) {
                /* Sub-window should not shuffle pointers (parent owns them) */
                int     row;
                cchar_t save;
                int     first;

                if (n > 0) {
                        for (row = w->_top; row < w->_bottom; row++) {
                                if (row < w->_bottom - n) {
                                        if (!w->_line[row+n][0]._f)     {
                                                /*
                                                 * Tail end of
                                                 * a multi-col-char
                                                 */
                                                (void) __m_cc_erase(w, row + n,
                                                        0, row + n, 0);
                                        }
                                        /*
                                         * Erase trailing multi-col-chars
                                         * where they hang into parent window
                                         */
                                        first = __m_cc_first(w, row + n,
                                                w->_maxx - 1);
                                        save = w->_line[row + n][first];
                                        (void) __m_cc_erase(w, row + n,
                                                first, row + n, first);
                                        w->_line[row + n][first] = save;
                                        (void) memcpy(w->_line[row],
                                                w->_line[row + n],
                                                sizeof (cchar_t) * w->_maxx);
                                } else {
                                        (void) __m_cc_erase(w, row, 0,
                                                w->_bottom -1, w->_maxx - 1);
                                        break;
                                }
                        }
                } else {
                        abort();
                }
        } else {
                /*
                 * Shuffle pointers in order to scroll.  The region
                 * from start to finish inclusive will be moved to
                 * either the top or bottom of _line[].
                 */
                if (0 < n) {
                        start = w->_top;
                        finish = w->_top + n - 1;
                        to = w->_bottom;
                } else {
                        start = w->_bottom + n;
                        finish = w->_bottom - 1;
                        to = w->_top;
                }

                /* Blank out new lines. */
                (void) __m_cc_erase(w, start, 0, finish, w->_maxx - 1);

                /* Scroll lines by shuffling pointers. */
                (void) __m_ptr_move((void **) w->_line, w->_maxy,
                        start, finish, to);
        }

        if ((w->_flags & W_FULL_WINDOW) &&
                w->_top == 0 && w->_bottom == w->_maxy)
                w->_scroll += (short) n;
        else
                w->_scroll = 0;

        (void) wtouchln(w, 0, w->_maxy, 1);
        wtouchln_hard(w, 0, w->_maxy);

#ifdef  BREAKS_fimmedok_fimmedok1_2
        w->_flags |= W_FLUSH;
#endif  /* BREAKS_fimmedok_fimmedok1_2 */

        WSYNC(w);

        return (WFLUSH(w));
}