fs/btrfs/hash.h

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #ifndef __HASH__
  20 #define __HASH__
  21
  22 int __init btrfs_hash_init(void);
  23
  24 void btrfs_hash_exit(void);
  25
  26 u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length);
  27
  28 static inline u64 btrfs_name_hash(const char *name, int len)
  29 {
  30         return btrfs_crc32c((u32)~1, name, len);
  31 }
  32
  33 /*
  34  * Figure the key offset of an extended inode ref
  35  */
  36 static inline u64 btrfs_extref_hash(u64 parent_objectid, const char *name,
  37                                     int len)
  38 {
  39         return (u64) btrfs_crc32c(parent_objectid, name, len);
  40 }
  41
  42 #endif