The GtkRadiant sources as originally released under the GPL license.

libs/generic/constant.h

@@ -0,0 +1,48 @@
+/*
+Copyright (C) 2001-2006, William Joseph.
+All Rights Reserved.
+
+This file is part of GtkRadiant.
+
+GtkRadiant 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.
+
+GtkRadiant 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 GtkRadiant; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#if !defined(INCLUDED_GENERIC_CONSTANT_H)
+#define INCLUDED_GENERIC_CONSTANT_H
+
+/// \file
+/// \brief Language extensions for constants that are guaranteed to be evaluated at compile-time.
+
+/// \brief A compile-time-constant as a type.
+template<typename Type>
+struct ConstantWrapper
+{
+  typedef typename Type::Value Value;
+  operator Value() const
+  {
+    return Type::evaluate();
+  }
+};
+template<typename TextOutputStreamType,  typename Type>
+inline TextOutputStreamType& ostream_write(TextOutputStreamType& ostream, const ConstantWrapper<Type>& c)
+{
+  return ostream_write(ostream, typename Type::Value(c));
+}
+
+#define TYPE_CONSTANT(name, value, type) struct name##_CONSTANT_ { typedef type Value; static Value evaluate() { return value; } }; typedef ConstantWrapper<name##_CONSTANT_> name
+#define STRING_CONSTANT(name, value) TYPE_CONSTANT(name, value, const char*)
+#define INTEGER_CONSTANT(name, value) TYPE_CONSTANT(name, value, int)
+
+#endif