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![Jeff Mahoney](/assets/img/avatar_default.png)
This patch reformats comments in the reiserfs code to fit in 80 columns and to follow the style rules. There is no functional change but it helps make my eyes bleed less. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Jan Kara <jack@suse.cz>
177 lines
3.5 KiB
C
177 lines
3.5 KiB
C
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/*
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* Keyed 32-bit hash function using TEA in a Davis-Meyer function
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* H0 = Key
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* Hi = E Mi(Hi-1) + Hi-1
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*
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* (see Applied Cryptography, 2nd edition, p448).
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*
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* Jeremy Fitzhardinge <jeremy@zip.com.au> 1998
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*
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* Jeremy has agreed to the contents of reiserfs/README. -Hans
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* Yura's function is added (04/07/2000)
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*/
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#include <linux/kernel.h>
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#include "reiserfs.h"
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#include <asm/types.h>
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#define DELTA 0x9E3779B9
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#define FULLROUNDS 10 /* 32 is overkill, 16 is strong crypto */
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#define PARTROUNDS 6 /* 6 gets complete mixing */
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/* a, b, c, d - data; h0, h1 - accumulated hash */
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#define TEACORE(rounds) \
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do { \
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u32 sum = 0; \
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int n = rounds; \
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u32 b0, b1; \
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\
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b0 = h0; \
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b1 = h1; \
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\
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do \
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{ \
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sum += DELTA; \
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b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b); \
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b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d); \
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} while(--n); \
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\
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h0 += b0; \
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h1 += b1; \
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} while(0)
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u32 keyed_hash(const signed char *msg, int len)
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{
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u32 k[] = { 0x9464a485, 0x542e1a94, 0x3e846bff, 0xb75bcfc3 };
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u32 h0 = k[0], h1 = k[1];
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u32 a, b, c, d;
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u32 pad;
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int i;
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/* assert(len >= 0 && len < 256); */
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pad = (u32) len | ((u32) len << 8);
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pad |= pad << 16;
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while (len >= 16) {
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a = (u32) msg[0] |
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(u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
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b = (u32) msg[4] |
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(u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24;
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c = (u32) msg[8] |
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(u32) msg[9] << 8 |
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(u32) msg[10] << 16 | (u32) msg[11] << 24;
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d = (u32) msg[12] |
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(u32) msg[13] << 8 |
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(u32) msg[14] << 16 | (u32) msg[15] << 24;
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TEACORE(PARTROUNDS);
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len -= 16;
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msg += 16;
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}
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if (len >= 12) {
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a = (u32) msg[0] |
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(u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
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b = (u32) msg[4] |
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(u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24;
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c = (u32) msg[8] |
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(u32) msg[9] << 8 |
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(u32) msg[10] << 16 | (u32) msg[11] << 24;
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d = pad;
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for (i = 12; i < len; i++) {
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d <<= 8;
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d |= msg[i];
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}
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} else if (len >= 8) {
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a = (u32) msg[0] |
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(u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
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b = (u32) msg[4] |
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(u32) msg[5] << 8 | (u32) msg[6] << 16 | (u32) msg[7] << 24;
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c = d = pad;
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for (i = 8; i < len; i++) {
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c <<= 8;
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c |= msg[i];
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}
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} else if (len >= 4) {
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a = (u32) msg[0] |
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(u32) msg[1] << 8 | (u32) msg[2] << 16 | (u32) msg[3] << 24;
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b = c = d = pad;
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for (i = 4; i < len; i++) {
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b <<= 8;
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b |= msg[i];
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}
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} else {
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a = b = c = d = pad;
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for (i = 0; i < len; i++) {
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a <<= 8;
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a |= msg[i];
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}
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}
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TEACORE(FULLROUNDS);
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/* return 0;*/
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return h0 ^ h1;
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}
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/*
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* What follows in this file is copyright 2000 by Hans Reiser, and the
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* licensing of what follows is governed by reiserfs/README
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*/
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u32 yura_hash(const signed char *msg, int len)
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{
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int j, pow;
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u32 a, c;
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int i;
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for (pow = 1, i = 1; i < len; i++)
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pow = pow * 10;
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if (len == 1)
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a = msg[0] - 48;
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else
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a = (msg[0] - 48) * pow;
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for (i = 1; i < len; i++) {
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c = msg[i] - 48;
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for (pow = 1, j = i; j < len - 1; j++)
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pow = pow * 10;
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a = a + c * pow;
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}
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for (; i < 40; i++) {
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c = '0' - 48;
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for (pow = 1, j = i; j < len - 1; j++)
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pow = pow * 10;
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a = a + c * pow;
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}
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for (; i < 256; i++) {
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c = i;
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for (pow = 1, j = i; j < len - 1; j++)
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pow = pow * 10;
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a = a + c * pow;
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}
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a = a << 7;
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return a;
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}
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u32 r5_hash(const signed char *msg, int len)
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{
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u32 a = 0;
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while (*msg) {
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a += *msg << 4;
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a += *msg >> 4;
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a *= 11;
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msg++;
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}
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return a;
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}
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