/*
 * 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 Mircrosystems, Inc.
 * All rights reserved.
 */

/*LINTLIBRARY*/

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

static void
link_col_major(MENU *m)
{
        ITEM *i;
        int n;
        short c, r;
        int left, up;

        r = 0;
        c = 0;
        for (i = IthItem(m, 0), n = 0; i; i = IthItem(m, ++n)) {
                X(i) = c;
                Y(i) = r;
                Left(i) = c ? IthItem(m, n-Rows(m)) : (ITEM *) NULL;
                if (n + Rows(m) >= Nitems(m)) {
                        Right(i) = (ITEM *) NULL;
                } else {
                        Right(i) = IthItem(m, n + Rows(m));
                }
                Up(i) = r ? IthItem(m, n-1) : (ITEM *) NULL;
                Down(i) = (r == Rows(m)-1) ? (ITEM *)0 : IthItem(m, n+1);
                if (++r == Rows(m)) {
                        r = 0;
                        c += 1;
                }
        }
        if (r) {
                Down(IthItem(m, n-1)) = IthItem(m, n - Rows(m));
        }

        if (Cyclic(m)) {
                /* Set up left and right links at edge of menu */

                r = Rows(m) * (Nitems(m)/Rows(m));
                for (n = 0; n < Rows(m); n++) {
                        left = n + r;
                        if (left >= Nitems(m)) {
                                left -= Rows(m);
                        }
                        Left(IthItem(m, n)) = IthItem(m, left);
                        Right(IthItem(m, left)) = IthItem(m, n);
                }

                /* Setup up and down links at edge of menu */

                for (n = 0; n < Nitems(m); n += Rows(m)) {
                        up = n + Rows(m) - 1;
                        if (up >= Nitems(m)) {
                                Up(IthItem(m, n)) = IthItem(m, n-1);
                        } else {
                                Up(IthItem(m, n)) = IthItem(m, up);
                                Down(IthItem(m, up)) = IthItem(m, n);
                        }
                }
        }
}

static void
link_row_major(MENU *m)
{
        int n;
        short c, r;
        ITEM *i;
        int left, up;

        r = 0;
        c = 0;
        for (i = IthItem(m, 0), n = 0; i; i = IthItem(m, ++n)) {
                X(i) = c;
                Y(i) = r;
                Left(i) = c ? IthItem(m, n-1) : (ITEM *) NULL;
                Right(i) = (c == Cols(m)-1 || n == Nitems(m)-1) ? (ITEM *)0 :
                                IthItem(m, n+1);
                Up(i) = r ? IthItem(m, n-Cols(m)) : (ITEM *) NULL;

                if (n+Cols(m) < Nitems(m)) {
                        Down(i) = IthItem(m, n + Cols(m));
                } else {
                        if (r == Rows(m)-1) {
                                /* Down is undefined if this is a complete */
                                /* last column */
                                Down(i) = (ITEM *) NULL;
                        } else {
                                /* Down is set to last item if the last */
                                /* column isn't full */
                                Down(i) = IthItem(m, Nitems(m)-1);
                        }
                }
                if (++c == Cols(m)) {
                        c = 0;
                        r += 1;
                }
        }

        if (Cyclic(m)) {

                /* Setup left and right links at edge of menu */

                for (n = 0; n < Nitems(m); n += Cols(m)) {
                        left = n + Cols(m) - 1;
                        if (left >= Nitems(m)) {
                                left = Nitems(m) - 1;
                        }
                        Left(IthItem(m, n)) = IthItem(m, left);
                        Right(IthItem(m, left)) = IthItem(m, n);
                }

                /* Setup up and down links at edge of menu */

                r = (Rows(m) - 1) * Cols(m);
                for (n = 0; n < Cols(m); n++) {
                        up = n + r;

                        /* If there is an incomplete line below this one */
                        /* the point to the last item in the menu. */

                        if (up >= Nitems(m)) {
                                Up(IthItem(m, n)) = IthItem(m, Nitems(m)-1);
                        } else {
                                Up(IthItem(m, n)) = IthItem(m, up);
                                Down(IthItem(m, up)) = IthItem(m, n);
                        }
                }
        }
}

void
_link_items(MENU *m)
{
        if (Items(m) && IthItem(m, 0)) {
                ResetLink(m);
                if (RowMajor(m)) {
                        link_row_major(m);
                } else {
                        link_col_major(m);
                }
        }
}