summaryrefslogtreecommitdiff
path: root/lib
diff options
context:
space:
mode:
Diffstat (limited to 'lib')
-rw-r--r--lib/ChangeLog2
-rw-r--r--lib/Makefile.am4
-rw-r--r--lib/jhash.c170
-rw-r--r--lib/jhash.h44
4 files changed, 218 insertions, 2 deletions
diff --git a/lib/ChangeLog b/lib/ChangeLog
index bbf71dcb..6bb039de 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -2,6 +2,8 @@
* Merge Kunihiro's 'show route-map' change and add
compatibility aliases for route-map continue
+ * jhash.{c,h}: New files. Bob Jenkins' public domain hashing
+ function, as implemented in linux kernel by David Miller.
2004-07-09 Juris Kalnins <juris@mt.lv>
diff --git a/lib/Makefile.am b/lib/Makefile.am
index eef9570f..f49566d4 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -11,7 +11,7 @@ libzebra_la_SOURCES = \
sockunion.c prefix.c thread.c if.c memory.c buffer.c table.c hash.c \
filter.c routemap.c distribute.c stream.c str.c log.c plist.c \
zclient.c sockopt.c smux.c md5.c if_rmap.c keychain.c privs.c \
- debug.c sigevent.c pqueue.c
+ debug.c sigevent.c pqueue.c jhash.c
libzebra_la_DEPENDENCIES = @LIB_REGEX@
@@ -22,7 +22,7 @@ pkginclude_HEADERS = \
memory.h network.h prefix.h routemap.h distribute.h sockunion.h \
str.h stream.h table.h thread.h vector.h version.h vty.h zebra.h \
plist.h zclient.h sockopt.h smux.h md5-gnu.h if_rmap.h keychain.h \
- privs.h debug.h sigevent.h pqueue.h
+ privs.h debug.h sigevent.h pqueue.h jhash.h
EXTRA_DIST = regex.c regex-gnu.h
diff --git a/lib/jhash.c b/lib/jhash.c
new file mode 100644
index 00000000..071fed6e
--- /dev/null
+++ b/lib/jhash.c
@@ -0,0 +1,170 @@
+/* jhash.h: Jenkins hash support.
+ *
+ * Copyright (C) 1996 Bob Jenkins (bob_jenkins@burtleburtle.net)
+ *
+ * http://burtleburtle.net/bob/hash/
+ *
+ * These are the credits from Bob's sources:
+ *
+ * lookup2.c, by Bob Jenkins, December 1996, Public Domain.
+ * hash(), hash2(), hash3, and mix() are externally useful functions.
+ * Routines to test the hash are included if SELF_TEST is defined.
+ * You can use this free for any purpose. It has no warranty.
+ *
+ * Copyright (C) 2003 David S. Miller (davem@redhat.com)
+ *
+ * I've modified Bob's hash to be useful in the Linux kernel, and
+ * any bugs present are surely my fault. -DaveM
+ */
+
+#include "zebra.h"
+#include "jhash.h"
+
+/* The golden ration: an arbitrary value */
+#define JHASH_GOLDEN_RATIO 0x9e3779b9
+
+/* NOTE: Arguments are modified. */
+#define __jhash_mix(a, b, c) \
+{ \
+ a -= b; a -= c; a ^= (c>>13); \
+ b -= c; b -= a; b ^= (a<<8); \
+ c -= a; c -= b; c ^= (b>>13); \
+ a -= b; a -= c; a ^= (c>>12); \
+ b -= c; b -= a; b ^= (a<<16); \
+ c -= a; c -= b; c ^= (b>>5); \
+ a -= b; a -= c; a ^= (c>>3); \
+ b -= c; b -= a; b ^= (a<<10); \
+ c -= a; c -= b; c ^= (b>>15); \
+}
+
+/* The most generic version, hashes an arbitrary sequence
+ * of bytes. No alignment or length assumptions are made about
+ * the input key.
+ */
+u_int32_t
+jhash (void *key, u_int32_t length, u_int32_t initval)
+{
+ u_int32_t a, b, c, len;
+ u_int8_t *k = key;
+
+ len = length;
+ a = b = JHASH_GOLDEN_RATIO;
+ c = initval;
+
+ while (len >= 12)
+ {
+ a +=
+ (k[0] + ((u_int32_t) k[1] << 8) + ((u_int32_t) k[2] << 16) +
+ ((u_int32_t) k[3] << 24));
+ b +=
+ (k[4] + ((u_int32_t) k[5] << 8) + ((u_int32_t) k[6] << 16) +
+ ((u_int32_t) k[7] << 24));
+ c +=
+ (k[8] + ((u_int32_t) k[9] << 8) + ((u_int32_t) k[10] << 16) +
+ ((u_int32_t) k[11] << 24));
+
+ __jhash_mix (a, b, c);
+
+ k += 12;
+ len -= 12;
+ }
+
+ c += length;
+ switch (len)
+ {
+ case 11:
+ c += ((u_int32_t) k[10] << 24);
+ case 10:
+ c += ((u_int32_t) k[9] << 16);
+ case 9:
+ c += ((u_int32_t) k[8] << 8);
+ case 8:
+ b += ((u_int32_t) k[7] << 24);
+ case 7:
+ b += ((u_int32_t) k[6] << 16);
+ case 6:
+ b += ((u_int32_t) k[5] << 8);
+ case 5:
+ b += k[4];
+ case 4:
+ a += ((u_int32_t) k[3] << 24);
+ case 3:
+ a += ((u_int32_t) k[2] << 16);
+ case 2:
+ a += ((u_int32_t) k[1] << 8);
+ case 1:
+ a += k[0];
+ };
+
+ __jhash_mix (a, b, c);
+
+ return c;
+}
+
+/* A special optimized version that handles 1 or more of u_int32_ts.
+ * The length parameter here is the number of u_int32_ts in the key.
+ */
+u_int32_t
+jhash2 (u_int32_t * k, u_int32_t length, u_int32_t initval)
+{
+ u_int32_t a, b, c, len;
+
+ a = b = JHASH_GOLDEN_RATIO;
+ c = initval;
+ len = length;
+
+ while (len >= 3)
+ {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ __jhash_mix (a, b, c);
+ k += 3;
+ len -= 3;
+ }
+
+ c += length * 4;
+
+ switch (len)
+ {
+ case 2:
+ b += k[1];
+ case 1:
+ a += k[0];
+ };
+
+ __jhash_mix (a, b, c);
+
+ return c;
+}
+
+
+/* A special ultra-optimized versions that knows they are hashing exactly
+ * 3, 2 or 1 word(s).
+ *
+ * NOTE: In partilar the "c += length; __jhash_mix(a,b,c);" normally
+ * done at the end is not done here.
+ */
+u_int32_t
+jhash_3words (u_int32_t a, u_int32_t b, u_int32_t c, u_int32_t initval)
+{
+ a += JHASH_GOLDEN_RATIO;
+ b += JHASH_GOLDEN_RATIO;
+ c += initval;
+
+ __jhash_mix (a, b, c);
+
+ return c;
+}
+
+u_int32_t
+jhash_2words (u_int32_t a, u_int32_t b, u_int32_t initval)
+{
+ return jhash_3words (a, b, 0, initval);
+}
+
+u_int32_t
+jhash_1word (u_int32_t a, u_int32_t initval)
+{
+ return jhash_3words (a, 0, 0, initval);
+}
diff --git a/lib/jhash.h b/lib/jhash.h
new file mode 100644
index 00000000..86a721c9
--- /dev/null
+++ b/lib/jhash.h
@@ -0,0 +1,44 @@
+/* jhash.h: Jenkins hash support.
+ *
+ * Copyright (C) 1996 Bob Jenkins (bob_jenkins@burtleburtle.net)
+ *
+ * http://burtleburtle.net/bob/hash/
+ *
+ * These are the credits from Bob's sources:
+ *
+ * lookup2.c, by Bob Jenkins, December 1996, Public Domain.
+ * hash(), hash2(), hash3, and mix() are externally useful functions.
+ * Routines to test the hash are included if SELF_TEST is defined.
+ * You can use this free for any purpose. It has no warranty.
+ *
+ * Copyright (C) 2003 David S. Miller (davem@redhat.com)
+ *
+ * I've modified Bob's hash to be useful in the Linux kernel, and
+ * any bugs present are surely my fault. -DaveM
+ */
+
+#ifndef _QUAGGA_JHASH_H
+#define _QUAGGA_JHASH_H
+
+/* The most generic version, hashes an arbitrary sequence
+ * of bytes. No alignment or length assumptions are made about
+ * the input key.
+ */
+u_int32_t jhash(void *key, u_int32_t length, u_int32_t initval);
+
+/* A special optimized version that handles 1 or more of u_int32_ts.
+ * The length parameter here is the number of u_int32_ts in the key.
+ */
+u_int32_t jhash2(u_int32_t *k, u_int32_t length, u_int32_t initval);
+
+/* A special ultra-optimized versions that knows they are hashing exactly
+ * 3, 2 or 1 word(s).
+ *
+ * NOTE: In partilar the "c += length; __jhash_mix(a,b,c);" normally
+ * done at the end is not done here.
+ */
+u_int32_t jhash_3words(u_int32_t a, u_int32_t b, u_int32_t c, u_int32_t initval);
+u_int32_t jhash_2words(u_int32_t a, u_int32_t b, u_int32_t initval);
+u_int32_t jhash_1word(u_int32_t a, u_int32_t initval);
+
+#endif /* _QUAGGA_JHASH_H */
generated by cgit v1.2.1 (git 2.18.0) at 2024-12-25 19:49:59 +0000