da99898c78
Add (untested and simple) directory item code Fix comp_keys to use the new key ordering Add btrfs_insert_empty_item
86 lines
1.6 KiB
C
86 lines
1.6 KiB
C
/*
|
|
* 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;
|
|
}
|
|
|
|
int btrfs_name_hash(const char *name, int len, u64 *hash_result)
|
|
{
|
|
__u32 hash;
|
|
__u32 minor_hash = 0;
|
|
const char *p;
|
|
__u32 in[8], buf[2];
|
|
|
|
/* 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 0;
|
|
}
|