linux/fs/reiserfs/hashes.c
Linus Torvalds bd4c625c06 reiserfs: run scripts/Lindent on reiserfs code
This was a pure indentation change, using:

	scripts/Lindent fs/reiserfs/*.c include/linux/reiserfs_*.h

to make reiserfs match the regular Linux indentation style.  As Jeff
Mahoney <jeffm@suse.com> writes:

 The ReiserFS code is a mix of a number of different coding styles, sometimes
 different even from line-to-line. Since the code has been relatively stable
 for quite some time and there are few outstanding patches to be applied, it
 is time to reformat the code to conform to the Linux style standard outlined
 in Documentation/CodingStyle.

 This patch contains the result of running scripts/Lindent against
 fs/reiserfs/*.c and include/linux/reiserfs_*.h. There are places where the
 code can be made to look better, but I'd rather keep those patches separate
 so that there isn't a subtle by-hand hand accident in the middle of a huge
 patch. To be clear: This patch is reformatting *only*.

 A number of patches may follow that continue to make the code more consistent
 with the Linux coding style.

 Hans wasn't particularly enthusiastic about these patches, but said he
 wouldn't really oppose them either.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-12 20:21:28 -07:00

183 lines
3.6 KiB
C

/*
* 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 reiserfs/README. -Hans
* Yura's function is added (04/07/2000)
*/
//
// keyed_hash
// yura_hash
// r5_hash
//
#include <linux/kernel.h>
#include <asm/types.h>
#include <asm/bug.h>
#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 { \
u32 sum = 0; \
int n = rounds; \
u32 b0, b1; \
\
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)
u32 keyed_hash(const signed char *msg, int len)
{
u32 k[] = { 0x9464a485, 0x542e1a94, 0x3e846bff, 0xb75bcfc3 };
u32 h0 = k[0], h1 = k[1];
u32 a, b, c, d;
u32 pad;
int i;
// assert(len >= 0 && len < 256);
pad = (u32) len | ((u32) len << 8);
pad |= pad << 16;
while (len >= 16) {
a = (u32) msg[0] |
(u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
b = (u32) msg[4] |
(u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24;
c = (u32) msg[8] |
(u32) msg[9] << 8 |
(u32) msg[10] << 16 | (u32) msg[11] << 24;
d = (u32) msg[12] |
(u32) msg[13] << 8 |
(u32) msg[14] << 16 | (u32) msg[15] << 24;
TEACORE(PARTROUNDS);
len -= 16;
msg += 16;
}
if (len >= 12) {
a = (u32) msg[0] |
(u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
b = (u32) msg[4] |
(u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24;
c = (u32) msg[8] |
(u32) msg[9] << 8 |
(u32) msg[10] << 16 | (u32) msg[11] << 24;
d = pad;
for (i = 12; i < len; i++) {
d <<= 8;
d |= msg[i];
}
} else if (len >= 8) {
a = (u32) msg[0] |
(u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
b = (u32) msg[4] |
(u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24;
c = d = pad;
for (i = 8; i < len; i++) {
c <<= 8;
c |= msg[i];
}
} else if (len >= 4) {
a = (u32) msg[0] |
(u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) 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 reiserfs/README */
u32 yura_hash(const signed char *msg, int len)
{
int j, pow;
u32 a, c;
int i;
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;
}
u32 r5_hash(const signed char *msg, int len)
{
u32 a = 0;
while (*msg) {
a += *msg << 4;
a += *msg >> 4;
a *= 11;
msg++;
}
return a;
}