1 files changed, 94 insertions, 0 deletions
diff --git a/src/core/support/murmur_hash.c b/src/core/support/murmur_hash.c
new file mode 100644
index 0000000000..5d30263e52
--- /dev/null
+++ b/src/core/support/murmur_hash.c
@@ -0,0 +1,94 @@
+/*
+ *
+ * Copyright 2014, Google Inc.
+ * 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 Google Inc. 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.
+ *
+ */
+
+#include "src/core/support/murmur_hash.h"
+
+#define ROTL32(x, r) ((x) << (r)) | ((x) >> (32 - (r)))
+
+#define FMIX32(h)    \
+  (h) ^= (h) >> 16;  \
+  (h) *= 0x85ebca6b; \
+  (h) ^= (h) >> 13;  \
+  (h) *= 0xc2b2ae35; \
+  (h) ^= (h) >> 16;
+
+/* Block read - if your platform needs to do endian-swapping or can only
+   handle aligned reads, do the conversion here */
+#define GETBLOCK32(p, i) (p)[(i)]
+
+gpr_uint32 gpr_murmur_hash3(const void* key, size_t len, gpr_uint32 seed) {
+  const gpr_uint8* data = (const gpr_uint8*)key;
+  const int nblocks = len / 4;
+  int i;
+
+  gpr_uint32 h1 = seed;
+  gpr_uint32 k1 = 0;
+
+  const gpr_uint32 c1 = 0xcc9e2d51;
+  const gpr_uint32 c2 = 0x1b873593;
+
+  const gpr_uint32* blocks = (const uint32_t*)(data + nblocks * 4);
+  const uint8_t* tail = (const uint8_t*)(data + nblocks * 4);
+
+  /* body */
+  for (i = -nblocks; i; i++) {
+    gpr_uint32 k1 = GETBLOCK32(blocks, i);
+
+    k1 *= c1;
+    k1 = ROTL32(k1, 15);
+    k1 *= c2;
+
+    h1 ^= k1;
+    h1 = ROTL32(h1, 13);
+    h1 = h1 * 5 + 0xe6546b64;
+  }
+
+  /* tail */
+  switch (len & 3) {
+    case 3:
+      k1 ^= tail[2] << 16;
+    case 2:
+      k1 ^= tail[1] << 8;
+    case 1:
+      k1 ^= tail[0];
+      k1 *= c1;
+      k1 = ROTL32(k1, 15);
+      k1 *= c2;
+      h1 ^= k1;
+  };
+
+  /* finalization */
+  h1 ^= len;
+  FMIX32(h1);
+  return h1;
+}