xref: /titanic_52/usr/src/uts/common/fs/zfs/sys/unique.h (revision 18c2aff776a775d34a4c9893a4c72e0434d68e36)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #ifndef	_SYS_UNIQUE_H
28 #define	_SYS_UNIQUE_H
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include <sys/zfs_context.h>
33 
34 #ifdef	__cplusplus
35 extern "C" {
36 #endif
37 
38 /* The number of significant bits in each unique value. */
39 #define	UNIQUE_BITS	56
40 
41 void unique_init(void);
42 
43 /* Return a new unique value. */
44 uint64_t unique_create(void);
45 
46 /* Return a unique value, which equals the one passed in if possible. */
47 uint64_t unique_insert(uint64_t value);
48 
49 /* Indicate that this value no longer needs to be uniquified against. */
50 void unique_remove(uint64_t value);
51 
52 #ifdef	__cplusplus
53 }
54 #endif
55 
56 #endif /* _SYS_UNIQUE_H */
57