Common: Added MurmurHash3 hash function for general-purpose use.

src/common/hash.h

@@ -0,0 +1,25 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "common/common_types.h"
+
+namespace Common {
+
+void MurmurHash3_128(const void* key, int len, u32 seed, void* out);
+
+/**
+ * Computes a 64-bit hash over the specified block of data
+ * @param data Block of data to compute hash over
+ * @param len Length of data (in bytes) to compute hash over
+ * @returns 64-bit hash value that was computed over the data block
+ */
+static inline u64 ComputeHash64(const void* data, int len) {
+    u64 res[2];
+    MurmurHash3_128(data, len, 0, res);
+    return res[0];
+}
+
+} // namespace Common