mirror of
https://github.com/kdave/btrfs-progs
synced 2024-12-22 22:23:32 +00:00
Switch btrfs_name_hash() to crc32c
Date: Tue, 19 Aug 2008 19:21:22 +0100 Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
parent
be8c87e176
commit
a2ec48bb6b
2
Makefile
2
Makefile
@ -2,7 +2,7 @@ CC=gcc
|
||||
AM_CFLAGS = -Wall -fno-strict-aliasing -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2
|
||||
CFLAGS = -g -Werror -Os
|
||||
objects = ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \
|
||||
root-tree.o dir-item.o hash.o file-item.o inode-item.o \
|
||||
root-tree.o dir-item.o file-item.o inode-item.o \
|
||||
inode-map.o crc32c.o rbtree.o extent-cache.o extent_io.o \
|
||||
volumes.o utils.o
|
||||
#
|
||||
|
105
hash.c
105
hash.c
@ -1,105 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
/*
|
||||
* Original copy from:
|
||||
* linux/fs/ext3/hash.c
|
||||
*
|
||||
* Copyright (C) 2002 by Theodore Ts'o
|
||||
*
|
||||
* This file is released under the GPL v2.
|
||||
*
|
||||
* This file may be redistributed under the terms of the GNU Public
|
||||
* License.
|
||||
*/
|
||||
|
||||
#include "kerncompat.h"
|
||||
#define DELTA 0x9E3779B9
|
||||
|
||||
static void TEA_transform(__u32 buf[2], __u32 const in[])
|
||||
{
|
||||
__u32 sum = 0;
|
||||
__u32 b0 = buf[0], b1 = buf[1];
|
||||
__u32 a = in[0], b = in[1], c = in[2], d = in[3];
|
||||
int n = 16;
|
||||
|
||||
do {
|
||||
sum += DELTA;
|
||||
b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
|
||||
b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
|
||||
} while(--n);
|
||||
|
||||
buf[0] += b0;
|
||||
buf[1] += b1;
|
||||
}
|
||||
|
||||
static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
|
||||
{
|
||||
__u32 pad, val;
|
||||
int i;
|
||||
|
||||
pad = (__u32)len | ((__u32)len << 8);
|
||||
pad |= pad << 16;
|
||||
|
||||
val = pad;
|
||||
if (len > num*4)
|
||||
len = num * 4;
|
||||
for (i=0; i < len; i++) {
|
||||
if ((i % 4) == 0)
|
||||
val = pad;
|
||||
val = msg[i] + (val << 8);
|
||||
if ((i % 4) == 3) {
|
||||
*buf++ = val;
|
||||
val = pad;
|
||||
num--;
|
||||
}
|
||||
}
|
||||
if (--num >= 0)
|
||||
*buf++ = val;
|
||||
while (--num >= 0)
|
||||
*buf++ = pad;
|
||||
}
|
||||
|
||||
u64 btrfs_name_hash(const char *name, int len)
|
||||
{
|
||||
__u32 hash;
|
||||
__u32 minor_hash = 0;
|
||||
const char *p;
|
||||
__u32 in[8], buf[4];
|
||||
u64 hash_result;
|
||||
|
||||
/* Initialize the default seed for the hash checksum functions */
|
||||
buf[0] = 0x67452301;
|
||||
buf[1] = 0xefcdab89;
|
||||
buf[2] = 0x98badcfe;
|
||||
buf[3] = 0x10325476;
|
||||
|
||||
p = name;
|
||||
while (len > 0) {
|
||||
str2hashbuf(p, len, in, 4);
|
||||
TEA_transform(buf, in);
|
||||
len -= 16;
|
||||
p += 16;
|
||||
}
|
||||
hash = buf[0];
|
||||
minor_hash = buf[1];
|
||||
hash_result = buf[0];
|
||||
hash_result <<= 32;
|
||||
hash_result |= buf[1];
|
||||
return hash_result;
|
||||
}
|
Loading…
Reference in New Issue
Block a user