LXR linux/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
  22int __init btrfs_hash_init(void);
  23
  24void btrfs_hash_exit(void);
  25const char* btrfs_crc32c_impl(void);
  26
  27u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length);
  28
  29static inline u64 btrfs_name_hash(const char *name, int len)
  30{
  31        return btrfs_crc32c((u32)~1, name, len);
  32}
  33
  34/*
  35 * Figure the key offset of an extended inode ref
  36 */
  37static inline u64 btrfs_extref_hash(u64 parent_objectid, const char *name,
  38                                    int len)
  39{
  40        return (u64) btrfs_crc32c(parent_objectid, name, len);
  41}
  42
  43#endif
  44