summaryrefslogtreecommitdiff
path: root/fs/reiserfs/hashes.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/reiserfs/hashes.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/reiserfs/hashes.c')
-rw-r--r--fs/reiserfs/hashes.c209
1 files changed, 209 insertions, 0 deletions
diff --git a/fs/reiserfs/hashes.c b/fs/reiserfs/hashes.c
new file mode 100644
index 000000000000..08d0508c2d39
--- /dev/null
+++ b/fs/reiserfs/hashes.c
@@ -0,0 +1,209 @@
+
+/*
+ * 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;
+}