Common: Add HashCombine.h

common/CMakeLists.txt

@@ -76,6 +76,7 @@ target_sources(common PRIVATE
 	General.h
 	GL/Context.h
 	GL/StreamBuffer.h
+	HashCombine.h
 	MemcpyFast.h
 	MemsetFast.inl
 	Path.h

common/HashCombine.h

@@ -0,0 +1,26 @@
+/*  PCSX2 - PS2 Emulator for PCs
+ *  Copyright (C) 2002-2021  PCSX2 Dev Team
+ *
+ *  PCSX2 is free software: you can redistribute it and/or modify it under the terms
+ *  of the GNU Lesser General Public License as published by the Free Software Found-
+ *  ation, either version 3 of the License, or (at your option) any later version.
+ *
+ *  PCSX2 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 PCSX2.
+ *  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <functional>
+#include <utility>
+
+template <typename T, typename... Rest>
+static inline void HashCombine(std::size_t& seed, const T& v, Rest&&... rest)
+{
+	seed ^= std::hash<T>{}(v) + 0x9e3779b9u + (seed << 6) + (seed >> 2);
+	(HashCombine(seed, std::forward<Rest>(rest)), ...);
+}

common/common.vcxproj

@@ -112,6 +112,7 @@
     <ClInclude Include="GL\ContextWGL.h" />
     <ClInclude Include="GL\StreamBuffer.h" />
     <ClInclude Include="FileSystem.h" />
+    <ClInclude Include="HashCombine.h" />
     <ClInclude Include="ProgressCallback.h" />
     <ClInclude Include="ScopedGuard.h" />
     <ClInclude Include="StringUtil.h" />

common/common.vcxproj.filters

@@ -330,6 +330,9 @@
     <ClInclude Include="ScopedGuard.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="HashCombine.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <Filter Include="Source Files">