summaryrefslogtreecommitdiff
path: root/lib/librte_hash/rte_jhash.h
diff options
context:
space:
mode:
Diffstat (limited to 'lib/librte_hash/rte_jhash.h')
-rw-r--r--lib/librte_hash/rte_jhash.h263
1 files changed, 263 insertions, 0 deletions
diff --git a/lib/librte_hash/rte_jhash.h b/lib/librte_hash/rte_jhash.h
new file mode 100644
index 0000000..12f794c
--- /dev/null
+++ b/lib/librte_hash/rte_jhash.h
@@ -0,0 +1,263 @@
+/*-
+ * BSD LICENSE
+ *
+ * Copyright(c) 2010-2012 Intel Corporation. All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * version: DPDK.L.1.2.3-3
+ */
+
+#ifndef _RTE_JHASH_H
+#define _RTE_JHASH_H
+
+/**
+ * @file
+ *
+ * jhash functions.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+/* 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.
+ *
+ * $FreeBSD$
+ */
+
+/** @internal Internal function. NOTE: Arguments are modified. */
+#define __rte_jhash_mix(a, b, c) do { \
+ 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); \
+} while (0)
+
+/** The golden ratio: an arbitrary value. */
+#define RTE_JHASH_GOLDEN_RATIO 0x9e3779b9
+
+/**
+ * The most generic version, hashes an arbitrary sequence
+ * of bytes. No alignment or length assumptions are made about
+ * the input key.
+ *
+ * @param key
+ * Key to calculate hash of.
+ * @param length
+ * Length of key in bytes.
+ * @param initval
+ * Initialising value of hash.
+ * @return
+ * Calculated hash value.
+ */
+static inline uint32_t
+rte_jhash(const void *key, uint32_t length, uint32_t initval)
+{
+ uint32_t a, b, c, len;
+ const uint8_t *k = (const uint8_t *) key;
+
+ len = length;
+ a = b = RTE_JHASH_GOLDEN_RATIO;
+ c = initval;
+
+ while (len >= 12) {
+ a += (k[0] + ((uint32_t)k[1] << 8) + ((uint32_t)k[2] << 16) +
+ ((uint32_t)k[3] << 24));
+ b += (k[4] + ((uint32_t)k[5] << 8) + ((uint32_t)k[6] << 16) +
+ ((uint32_t)k[7] << 24));
+ c += (k[8] + ((uint32_t)k[9] << 8) + ((uint32_t)k[10] << 16) +
+ ((uint32_t)k[11] << 24));
+
+ __rte_jhash_mix(a,b,c);
+
+ k += 12;
+ len -= 12;
+ }
+
+ c += length;
+ switch (len) {
+ case 11: c += ((uint32_t)k[10] << 24);
+ case 10: c += ((uint32_t)k[9] << 16);
+ case 9 : c += ((uint32_t)k[8] << 8);
+ case 8 : b += ((uint32_t)k[7] << 24);
+ case 7 : b += ((uint32_t)k[6] << 16);
+ case 6 : b += ((uint32_t)k[5] << 8);
+ case 5 : b += k[4];
+ case 4 : a += ((uint32_t)k[3] << 24);
+ case 3 : a += ((uint32_t)k[2] << 16);
+ case 2 : a += ((uint32_t)k[1] << 8);
+ case 1 : a += k[0];
+ default: break;
+ };
+
+ __rte_jhash_mix(a,b,c);
+
+ return c;
+}
+
+/**
+ * A special optimized version that handles 1 or more of uint32_ts.
+ * The length parameter here is the number of uint32_ts in the key.
+ *
+ * @param k
+ * Key to calculate hash of.
+ * @param length
+ * Length of key in units of 4 bytes.
+ * @param initval
+ * Initialising value of hash.
+ * @return
+ * Calculated hash value.
+ */
+static inline uint32_t
+rte_jhash2(uint32_t *k, uint32_t length, uint32_t initval)
+{
+ uint32_t a, b, c, len;
+
+ a = b = RTE_JHASH_GOLDEN_RATIO;
+ c = initval;
+ len = length;
+
+ while (len >= 3) {
+ a += k[0];
+ b += k[1];
+ c += k[2];
+ __rte_jhash_mix(a, b, c);
+ k += 3; len -= 3;
+ }
+
+ c += length * 4;
+
+ switch (len) {
+ case 2 : b += k[1];
+ case 1 : a += k[0];
+ default: break;
+ };
+
+ __rte_jhash_mix(a,b,c);
+
+ return c;
+}
+
+
+/**
+ * A special ultra-optimized versions that knows it is hashing exactly
+ * 3 words.
+ *
+ * @param a
+ * First word to calcuate hash of.
+ * @param b
+ * Second word to calcuate hash of.
+ * @param c
+ * Third word to calcuate hash of.
+ * @param initval
+ * Initialising value of hash.
+ * @return
+ * Calculated hash value.
+ */
+static inline uint32_t
+rte_jhash_3words(uint32_t a, uint32_t b, uint32_t c, uint32_t initval)
+{
+ a += RTE_JHASH_GOLDEN_RATIO;
+ b += RTE_JHASH_GOLDEN_RATIO;
+ c += initval;
+
+ __rte_jhash_mix(a, b, c);
+
+ /*
+ * NOTE: In particular the "c += length; __rte_jhash_mix(a,b,c);"
+ * normally done at the end is not done here.
+ */
+ return c;
+}
+
+/**
+ * A special ultra-optimized versions that knows it is hashing exactly
+ * 2 words.
+ *
+ * NOTE: In partilar the "c += length; __rte_jhash_mix(a,b,c);" normally
+ * done at the end is not done here.
+ *
+ * @param a
+ * First word to calcuate hash of.
+ * @param b
+ * Second word to calcuate hash of.
+ * @param initval
+ * Initialising value of hash.
+ * @return
+ * Calculated hash value.
+ */
+static inline uint32_t
+rte_jhash_2words(uint32_t a, uint32_t b, uint32_t initval)
+{
+ return rte_jhash_3words(a, b, 0, initval);
+}
+
+/**
+ * A special ultra-optimized versions that knows it is hashing exactly
+ * 1 word.
+ *
+ * NOTE: In partilar the "c += length; __rte_jhash_mix(a,b,c);" normally
+ * done at the end is not done here.
+ *
+ * @param a
+ * Word to calcuate hash of.
+ * @param initval
+ * Initialising value of hash.
+ * @return
+ * Calculated hash value.
+ */
+static inline uint32_t
+rte_jhash_1word(uint32_t a, uint32_t initval)
+{
+ return rte_jhash_3words(a, 0, 0, initval);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_JHASH_H */