2004-07-09 Paul Jakma <paul@dishone.st>

        * jhash.{c,h}: New files. Bob Jenkins' public domain hashing
          function, as implemented in linux kernel by David Miller.

1 files changed, 44 insertions, 0 deletions

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 */