1/*	$NetBSD: blist.h,v 1.7 2005/12/11 12:25:20 christos Exp $	*/
2
3/*-
4 * Copyright (c) 1998 Matthew Dillon.  All Rights Reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
18 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
23 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
26 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
27 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30/*
31 * Implements bitmap resource lists.
32 *
33 *	Usage:
34 *		blist = blist_create(blocks)
35 *		(void)  blist_destroy(blist)
36 *		blkno = blist_alloc(blist, count)
37 *		(void)  blist_free(blist, blkno, count)
38 *		nblks = blist_fill(blist, blkno, count)
39 *		(void)  blist_resize(&blist, count, freeextra)
40 *
41 *
42 *	Notes:
43 *		on creation, the entire list is marked reserved.  You should
44 *		first blist_free() the sections you want to make available
45 *		for allocation before doing general blist_alloc()/free()
46 *		ops.
47 *
48 *		BLIST_NONE is returned on failure.  This module is typically
49 *		capable of managing up to (2^31) blocks per blist, though
50 *		the memory utilization would be insane if you actually did
51 *		that.  Managing something like 512MB worth of 4K blocks
52 *		eats around 32 KBytes of memory.
53 *
54 * $FreeBSD: src/sys/sys/blist.h,v 1.9 2005/01/07 02:29:23 imp Exp $
55 */
56
57#ifndef _SYS_BLIST_H_
58#define _SYS_BLIST_H_
59
60/*
61 * for space efficiency, sizeof(blist_bitmap_t) should be
62 * greater than or equal to sizeof(blist_blkno_t).
63 */
64
65typedef uint32_t blist_bitmap_t;
66typedef uint32_t blist_blkno_t;
67
68/*
69 * note: currently use BLIST_NONE as an absolute value rather than
70 * a flag bit.
71 */
72
73#define BLIST_NONE	((blist_blkno_t)-1)
74
75typedef struct blist *blist_t;
76
77#define BLIST_BMAP_RADIX	(sizeof(blist_bitmap_t)*8)
78#define BLIST_MAX_ALLOC		BLIST_BMAP_RADIX
79
80extern blist_t blist_create(blist_blkno_t blocks);
81extern void blist_destroy(blist_t blist);
82extern blist_blkno_t blist_alloc(blist_t blist, blist_blkno_t count);
83extern void blist_free(blist_t blist, blist_blkno_t blkno, blist_blkno_t count);
84extern blist_blkno_t blist_fill(blist_t bl, blist_blkno_t blkno,
85    blist_blkno_t count);
86extern void blist_print(blist_t blist);
87extern void blist_resize(blist_t *pblist, blist_blkno_t count, int freenew);
88
89#endif	/* _SYS_BLIST_H_ */
90
91