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/*
 * Copyright (C) 2005 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __BUDDY_H__
#define __BUDDY_H__

#include <arch/types.h>
#include <typedefs.h>

#define BUDDY_SYSTEM_INNER_BLOCK    0xff

/** Buddy system operations to be implemented by each implementations. */
struct buddy_system_operations {
    link_t *(* find_buddy)(buddy_system_t *, link_t *);     /**< Return pointer to left-side or right-side buddy for block passed as argument. */
    link_t *(* bisect)(buddy_system_t *, link_t *);         /**< Bisect the block passed as argument and return pointer to the new right-side buddy. */
    link_t *(* coalesce)(buddy_system_t *, link_t *, link_t *); /**< Coalesce two buddies into a bigger block. */
    void (*set_order)(buddy_system_t *, link_t *, __u8);        /**< Set order of block passed as argument. */
    __u8 (*get_order)(buddy_system_t *, link_t *);          /**< Return order of block passed as argument. */
    void (*mark_busy)(buddy_system_t *, link_t *);          /**< Mark block as busy */
};

struct buddy_system {
    __u8 max_order;
    link_t *order;
    buddy_system_operations_t *op;
    void *data;             /**< Pointer to be used by the implementation. */
};

extern buddy_system_t *buddy_system_create(__u8 max_order, buddy_system_operations_t *op, void *data);
extern link_t *buddy_system_alloc(buddy_system_t *b, __u8 i);
extern bool buddy_system_can_alloc(buddy_system_t *b, __u8 order);
extern void buddy_system_free(buddy_system_t *b, link_t *block);

#endif