[deliverable/linux.git] / fs / btrfs / hash.h

/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#ifndef __HASH__
#define __HASH__

int __init btrfs_hash_init(void);

void btrfs_hash_exit(void);
const char* btrfs_crc32c_impl(void);

u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length);

static inline u64 btrfs_name_hash(const char *name, int len)
{
	return btrfs_crc32c((u32)~1, name, len);
}

/*
 * Figure the key offset of an extended inode ref
 */
static inline u64 btrfs_extref_hash(u64 parent_objectid, const char *name,
				    int len)
{
	return (u64) btrfs_crc32c(parent_objectid, name, len);
}

#endif
Commit	Line	Data
	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	const char* btrfs_crc32c_impl(void);
	26
	27	u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length);
	28
	29	static 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	*/
	37	static 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