/* * 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 <linux/types.h> #include "hash.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]; if (len == 1 && *name == '.') { *hash_result = 1; return 0; } else if (len == 2 && name[0] == '.' && name[1] == '.') { *hash_result = 2; return 0; } /* 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; }