1 files changed, 51 insertions, 0 deletions
diff --git a/src/common/Utilities/Hash.h b/src/common/Utilities/Hash.h
new file mode 100644
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+++ b/src/common/Utilities/Hash.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2008-2017 TrinityCore <http://www.trinitycore.org/>
+ *
+ * This program 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 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TrinityCore_Hash_h__
+#define TrinityCore_Hash_h__
+
+#include <functional>
+#include <utility>
+
+namespace Trinity
+{
+    template<typename T>
+    inline void hash_combine(std::size_t& seed, T const& val)
+    {
+        seed ^= std::hash<T>()(val) + 0x9E3779B9 + (seed << 6) + (seed >> 2);
+    }
+}
+
+ //! Hash implementation for std::pair to allow using pairs in unordered_set or as key for unordered_map
+ //! Individual types used in pair must be hashable by std::hash
+namespace std
+{
+    template<class K, class V>
+    struct hash<std::pair<K, V>>
+    {
+    public:
+        size_t operator()(std::pair<K, V> const& p) const
+        {
+            size_t hashVal = 0;
+            Trinity::hash_combine(hashVal, p.first);
+            Trinity::hash_combine(hashVal, p.second);
+            return hashVal;
+        }
+    };
+}
+
+#endif // TrinityCore_Hash_h__