PSync: initial commit
refs: #4641
Change-Id: Iabed3ad7632544d97559e6798547b7972b416784
diff --git a/src/detail/util.cpp b/src/detail/util.cpp
new file mode 100644
index 0000000..ab2c541
--- /dev/null
+++ b/src/detail/util.cpp
@@ -0,0 +1,109 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2018, The University of Memphis
+ *
+ * This file is part of PSync.
+ * See AUTHORS.md for complete list of PSync authors and contributors.
+ *
+ * PSync is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * PSync is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * PSync, e.g., in COPYING.md file. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * murmurHash3 was written by Austin Appleby, and is placed in the public
+ * domain. The author hereby disclaims copyright to this source code.
+ * https://github.com/aappleby/smhasher/blob/master/src/murmurHash3.cpp
+ **/
+
+#include "util.hpp"
+
+#include <ndn-cxx/util/backports.hpp>
+
+#include <string>
+
+namespace psync {
+
+static uint32_t
+ROTL32 ( uint32_t x, int8_t r )
+{
+ return (x << r) | (x >> (32 - r));
+}
+
+uint32_t
+murmurHash3(uint32_t nHashSeed, const std::vector<unsigned char>& vDataToHash)
+{
+ uint32_t h1 = nHashSeed;
+ const uint32_t c1 = 0xcc9e2d51;
+ const uint32_t c2 = 0x1b873593;
+
+ const size_t nblocks = vDataToHash.size() / 4;
+
+ //----------
+ // body
+ const uint32_t * blocks = (const uint32_t *)(&vDataToHash[0] + nblocks*4);
+
+ for (size_t i = -nblocks; i; i++) {
+ uint32_t k1 = blocks[i];
+
+ k1 *= c1;
+ k1 = ROTL32(k1,15);
+ k1 *= c2;
+
+ h1 ^= k1;
+ h1 = ROTL32(h1,13);
+ h1 = h1*5+0xe6546b64;
+ }
+
+ //----------
+ // tail
+ const uint8_t * tail = (const uint8_t*)(&vDataToHash[0] + nblocks*4);
+
+ uint32_t k1 = 0;
+
+ switch (vDataToHash.size() & 3) {
+ case 3:
+ k1 ^= tail[2] << 16;
+ NDN_CXX_FALLTHROUGH;
+
+ case 2:
+ k1 ^= tail[1] << 8;
+ NDN_CXX_FALLTHROUGH;
+
+ case 1:
+ k1 ^= tail[0];
+ k1 *= c1; k1 = ROTL32(k1,15); k1 *= c2; h1 ^= k1;
+ }
+
+ //----------
+ // finalization
+ h1 ^= vDataToHash.size();
+ h1 ^= h1 >> 16;
+ h1 *= 0x85ebca6b;
+ h1 ^= h1 >> 13;
+ h1 *= 0xc2b2ae35;
+ h1 ^= h1 >> 16;
+
+ return h1;
+}
+
+uint32_t
+murmurHash3(uint32_t nHashSeed, const std::string& str)
+{
+ return murmurHash3(nHashSeed, std::vector<unsigned char>(str.begin(), str.end()));
+}
+
+uint32_t
+murmurHash3(uint32_t nHashSeed, uint32_t value)
+{
+ return murmurHash3(nHashSeed,
+ std::vector<unsigned char>((unsigned char*)&value,
+ (unsigned char*)&value + sizeof(uint32_t)));
+}
+
+} // namespace psync