module/zfs/include/sys/unique.h

   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
  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 */