COMMON: Introduce a shared hash function for pointer types

1 files changed, 43 insertions, 0 deletions

diff --git a/common/hash-ptr.h b/common/hash-ptr.h
new file mode 100644
index 0000000000..1099478c3b
--- /dev/null
+++ b/common/hash-ptr.h
@@ -0,0 +1,43 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef COMMON_HASH_PTR_H
+#define COMMON_HASH_PTR_H
+
+#include "common/func.h"
+
+namespace Common {
+
+/**
+ * Partial specialization of the Hash functor to be able to use pointers as HashMap keys
+ */
+template<typename T>
+struct Hash<T *> {
+	uint operator()(T * const &v) const {
+		uint x = static_cast<uint>(reinterpret_cast<uintptr>(v));
+		return x + (x >> 3);
+	}
+};
+
+} // End of namespace Common
+
+#endif