libc/xcurses/ptrmove.c

/*
 * 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) 1995-1998 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/* LINTLIBRARY */

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

#ifdef M_RCSID
#ifndef lint
static char rcsID[] = "$Header: /rd/src/libc/xcurses/rcs/ptrmove.c 1.3 "
"1995/05/18 20:55:05 ant Exp $";
#endif
#endif

#include <private.h>

static void reverse(void **, unsigned int, unsigned int);

/*
 * Move range start..finish inclusive before the given location.
 * Return -1 if the region to move is out of bounds or the target
 * falls within the region; 0 for success.
 *
 * (See Software Tools chapter 6.)
 */
int
__m_ptr_move(void **array, unsigned int length,
    unsigned int start, unsigned int finish, unsigned int to)
{
    if (finish < start || length <= finish)
        return (-1);

    if (to < start) {
        reverse(array, to, start-1);
        reverse(array, start, finish);
        reverse(array, to, finish);
    } else if (finish < to && to <= length) {
        reverse(array, start, finish);
        reverse(array, finish+1, to-1);
        reverse(array, start, to-1);
    } else {
        return (-1);
    }

    return (0);
}

/*
 * Reverse range a..b inclusive.
 */
static void
reverse(void **ptr, unsigned int a, unsigned int b)
{
    void    *temp;
    void    **a_ptr = &ptr[a];
    void    **b_ptr = &ptr[b];

    while (a_ptr < b_ptr) {
        temp = *a_ptr;
        *a_ptr++ = *b_ptr;
        *b_ptr-- = temp;
    }
}