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freebsd/sys/gnu/fs/reiserfs/reiserfs_hashes.c
Jean-Sébastien Pédron d6d3f5ac42 Moving reiserfs from sys/gnu to sys/gnu/fs. This was discussed on arch@.
Reviewed by:	mux (mentor)
Approved by:	re (scottl)
2005-06-18 17:10:50 +00:00

218 lines
4.2 KiB
C

/*-
* Copyright 2000 Hans Reiser
* See README for licensing and copyright details
*
* Ported to FreeBSD by Jean-Sébastien Pédron <jspedron@club-internet.fr>
*
* $FreeBSD$
*/
#include <gnu/fs/reiserfs/reiserfs_fs.h>
/*
* Keyed 32-bit hash function using TEA in a Davis-Meyer function
* H0 = Key
* Hi = E Mi(Hi-1) + Hi-1
*
* (see Applied Cryptography, 2nd edition, p448).
*
* Jeremy Fitzhardinge <jeremy@zip.com.au> 1998
*
* Jeremy has agreed to the contents of README. -Hans
* Yura's function is added (04/07/2000)
*/
/*
* keyed_hash
* yura_hash
* r5_hash
*/
#define DELTA 0x9E3779B9
#define FULLROUNDS 10 /* 32 is overkill, 16 is strong crypto */
#define PARTROUNDS 6 /* 6 gets complete mixing */
/* a, b, c, d - data; h0, h1 - accumulated hash */
#define TEACORE(rounds) \
do { \
int n; \
uint32_t b0, b1; \
uint32_t sum; \
\
n = rounds; \
sum = 0; \
b0 = h0; \
b1 = h1; \
\
do { \
sum += DELTA; \
b0 += ((b1 << 4) + a) ^ (b1+sum) ^ ((b1 >> 5) + b); \
b1 += ((b0 << 4) + c) ^ (b0+sum) ^ ((b0 >> 5) + d); \
} while (--n); \
\
h0 += b0; \
h1 += b1; \
} while (0)
uint32_t
keyed_hash(const signed char *msg, int len)
{
uint32_t k[] = { 0x9464a485, 0x542e1a94, 0x3e846bff, 0xb75bcfc3 };
uint32_t h0, h1;
uint32_t a, b, c, d;
uint32_t pad;
int i;
h0 = k[0];
h1 = k[1];
pad = (uint32_t)len | ((uint32_t)len << 8);
pad |= pad << 16;
while(len >= 16) {
a = (uint32_t)msg[ 0] |
(uint32_t)msg[ 1] << 8 |
(uint32_t)msg[ 2] << 16 |
(uint32_t)msg[ 3] << 24;
b = (uint32_t)msg[ 4] |
(uint32_t)msg[ 5] << 8 |
(uint32_t)msg[ 6] << 16 |
(uint32_t)msg[ 7] << 24;
c = (uint32_t)msg[ 8] |
(uint32_t)msg[ 9] << 8 |
(uint32_t)msg[10] << 16 |
(uint32_t)msg[11] << 24;
d = (uint32_t)msg[12] |
(uint32_t)msg[13] << 8 |
(uint32_t)msg[14] << 16 |
(uint32_t)msg[15] << 24;
TEACORE(PARTROUNDS);
len -= 16;
msg += 16;
}
if (len >= 12) {
a = (uint32_t)msg[ 0] |
(uint32_t)msg[ 1] << 8 |
(uint32_t)msg[ 2] << 16 |
(uint32_t)msg[ 3] << 24;
b = (uint32_t)msg[ 4] |
(uint32_t)msg[ 5] << 8 |
(uint32_t)msg[ 6] << 16 |
(uint32_t)msg[ 7] << 24;
c = (uint32_t)msg[ 8] |
(uint32_t)msg[ 9] << 8 |
(uint32_t)msg[10] << 16 |
(uint32_t)msg[11] << 24;
d = pad;
for(i = 12; i < len; i++) {
d <<= 8;
d |= msg[i];
}
} else if (len >= 8) {
a = (uint32_t)msg[ 0] |
(uint32_t)msg[ 1] << 8 |
(uint32_t)msg[ 2] << 16 |
(uint32_t)msg[ 3] << 24;
b = (uint32_t)msg[ 4] |
(uint32_t)msg[ 5] << 8 |
(uint32_t)msg[ 6] << 16 |
(uint32_t)msg[ 7] << 24;
c = d = pad;
for(i = 8; i < len; i++) {
c <<= 8;
c |= msg[i];
}
} else if (len >= 4) {
a = (uint32_t)msg[ 0] |
(uint32_t)msg[ 1] << 8 |
(uint32_t)msg[ 2] << 16 |
(uint32_t)msg[ 3] << 24;
b = c = d = pad;
for(i = 4; i < len; i++) {
b <<= 8;
b |= msg[i];
}
} else {
a = b = c = d = pad;
for(i = 0; i < len; i++) {
a <<= 8;
a |= msg[i];
}
}
TEACORE(FULLROUNDS);
/* return 0; */
return (h0 ^ h1);
}
/*
* What follows in this file is copyright 2000 by Hans Reiser, and the
* licensing of what follows is governed by README
* */
uint32_t
yura_hash(const signed char *msg, int len)
{
int i;
int j, pow;
uint32_t a, c;
for (pow = 1, i = 1; i < len; i++)
pow = pow * 10;
if (len == 1)
a = msg[0] - 48;
else
a = (msg[0] - 48) * pow;
for (i = 1; i < len; i++) {
c = msg[i] - 48;
for (pow = 1, j = i; j < len - 1; j++)
pow = pow * 10;
a = a + c * pow;
}
for (; i < 40; i++) {
c = '0' - 48;
for (pow = 1, j = i; j < len - 1; j++)
pow = pow * 10;
a = a + c * pow;
}
for (; i < 256; i++) {
c = i;
for (pow = 1, j = i; j < len - 1; j++)
pow = pow * 10;
a = a + c * pow;
}
a = a << 7;
return (a);
}
uint32_t
r5_hash(const signed char *msg, int len)
{
uint32_t a;
const signed char *start;
a = 0;
start = msg;
while (*msg && msg < start + len) {
a += *msg << 4;
a += *msg >> 4;
a *= 11;
msg++;
}
return (a);
}