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[protos/libecoli.git] / lib / ecoli_murmurhash.c

diff --git a/lib/ecoli_murmurhash.c b/lib/ecoli_murmurhash.c
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+++ b/lib/ecoli_murmurhash.c
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+/*
+ * Copyright (c) 2016, Olivier MATZ <zer0@droids-corp.org>
+ *
+ * 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 the University of California, Berkeley 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 REGENTS 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 REGENTS AND 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.
+ */
+
+#include <stdint.h>
+
+#include <ecoli_murmurhash.h>
+
+uint32_t ec_murmurhash3(const void *key, int len, uint32_t seed)
+{
+       const uint8_t *data = (const uint8_t *)key;
+       const uint8_t *tail;
+       const int nblocks = len / 4;
+       uint32_t h1 = seed;
+       uint32_t k1;
+       const uint32_t *blocks = (const uint32_t *)(data + nblocks * 4);
+       int i;
+
+       for (i = -nblocks; i; i++) {
+               k1 = blocks[i];
+
+               h1 = ec_murmurhash3_add32(h1, k1);
+               h1 = ec_murmurhash3_mix32(h1);
+       }
+
+       tail = (const uint8_t *)(data + nblocks * 4);
+       k1 = 0;
+
+       switch(len & 3) {
+       case 3: k1 ^= tail[2] << 16;
+       case 2: k1 ^= tail[1] << 8;
+       case 1: k1 ^= tail[0];
+               h1 = ec_murmurhash3_add32(h1, k1);
+       };
+
+       /* finalization */
+       h1 ^= len;
+       h1 = ec_murmurhash3_fmix32(h1);
+       return h1;
+}