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      1 /*	$NetBSD: blist.h,v 1.8 2013/12/09 09:35:17 wiz 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 
     65 typedef uint32_t blist_bitmap_t;
     66 typedef 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 
     75 typedef struct blist *blist_t;
     76 
     77 #define BLIST_BMAP_RADIX	(sizeof(blist_bitmap_t)*8)
     78 #define BLIST_MAX_ALLOC		BLIST_BMAP_RADIX
     79 
     80 extern blist_t blist_create(blist_blkno_t blocks);
     81 extern void blist_destroy(blist_t blist);
     82 extern blist_blkno_t blist_alloc(blist_t blist, blist_blkno_t count);
     83 extern void blist_free(blist_t blist, blist_blkno_t blkno, blist_blkno_t count);
     84 extern blist_blkno_t blist_fill(blist_t bl, blist_blkno_t blkno,
     85     blist_blkno_t count);
     86 extern void blist_print(blist_t blist);
     87 extern void blist_resize(blist_t *pblist, blist_blkno_t count, int freenew);
     88 
     89 #endif	/* _SYS_BLIST_H_ */
     90 
     91