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      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 (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 /*
     22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 #ifndef	_SYS_UNIQUE_H
     27 #define	_SYS_UNIQUE_H
     28 
     29 #pragma ident	"@(#)unique.h	1.2	07/08/02 SMI"
     30 
     31 #include <sys/zfs_context.h>
     32 
     33 #ifdef	__cplusplus
     34 extern "C" {
     35 #endif
     36 
     37 /* The number of significant bits in each unique value. */
     38 #define	UNIQUE_BITS	56
     39 
     40 void unique_init(void);
     41 void unique_fini(void);
     42 
     43 /*
     44  * Return a new unique value (which will not be uniquified against until
     45  * it is unique_insert()-ed.
     46  */
     47 uint64_t unique_create(void);
     48 
     49 /* Return a unique value, which equals the one passed in if possible. */
     50 uint64_t unique_insert(uint64_t value);
     51 
     52 /* Indicate that this value no longer needs to be uniquified against. */
     53 void unique_remove(uint64_t value);
     54 
     55 #ifdef	__cplusplus
     56 }
     57 #endif
     58 
     59 #endif /* _SYS_UNIQUE_H */
     60