haiku/headers/private/kernel/util/RadixBitmap.h

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/*-
* Copyright (c) 1998 Matthew Dillon. All Rights Reserved.
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 4. Neither the name of the University nor the names of its contributors
* may 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.
*/
/*
* The radix bitmap structure is ported from FreeBSD.
*/
#ifndef _KERNEL_UTIL_RADIX_BITMAP_H
#define _KERNEL_UTIL_RADIX_BITMAP_H
#include <SupportDefs.h>
typedef uint32 swap_addr_t;
typedef uint32 bitmap_t;
typedef struct radix_node {
union {
bitmap_t bitmap; // bitmap for the slots if we are a leaf
int32 available; // available slots under us if we are not a leaf
} u;
int32 big_hint; // the biggest continuous slots under us
} radix_node;
// Bitmap which uses radix tree for hinting.
// The radix tree is stored in an array.
typedef struct radix_bitmap {
swap_addr_t free_slots; // # of free slots
swap_addr_t radix; // coverage radix
swap_addr_t skip; // starting skip
radix_node *root; // root of radix tree, actually it is an array
swap_addr_t root_size; // size of the array(# of nodes in the tree)
} radix_bitmap;
#define BITMAP_RADIX (sizeof(swap_addr_t) * 8)
#define NODE_RADIX 16
#define SWAP_SLOT_NONE ((swap_addr_t)-1)
extern radix_bitmap *radix_bitmap_create(uint32 slots);
extern swap_addr_t radix_bitmap_alloc(radix_bitmap *bmp, uint32 count);
extern void radix_bitmap_dealloc(radix_bitmap *bmp, swap_addr_t slotIndex,
uint32 count);
extern void radix_bitmap_destroy(radix_bitmap *bmp);
#endif // _KERNEL_UTIL_RADIX_BITMAP_H