| /* |
| * 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. |
| */ |
| |
| #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; |
| } |