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

/*
 *      cscope - interactive C symbol or text cross-reference
 *
 *      command history
 */

#include <stdio.h>
#include "global.h"

HISTORY *head, *tail, *current;

/* add a cmd to the history list */
void
addcmd(int f, char *s)
{
        HISTORY *h;

        h = (HISTORY *)mymalloc(sizeof (HISTORY));
        if (tail) {
                tail->next = h;
                h->next = 0;
                h->previous = tail;
                tail = h;
        } else {
                head = tail = h;
                h->next = h->previous = 0;
        }
        h->field = f;
        h->text = stralloc(s);
        current = 0;
}

/* return previous history item */

HISTORY *
prevcmd(void)
{
        if (current) {
                if (current->previous)  /* stay on first item */
                        return (current = current->previous);
                else
                        return (current);
        } else if (tail)
                return (current = tail);
        else
                return (NULL);
}

/* return next history item */

HISTORY *
nextcmd(void)
{
        if (current) {
                if (current->next)      /* stay on first item */
                        return (current = current->next);
                else
                        return (current);
        } else
                return (NULL);
}

/* reset current to tail */

void
resetcmd(void)
{
        current = 0;
}

HISTORY *
currentcmd(void)
{
        return (current);
}