vmap/libs/generic/constant.h

50 lines
1.9 KiB
C++

/*
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 )
#define UINT_CONSTANT( name, value ) TYPE_CONSTANT ( name, value, unsigned int )
STRING_CONSTANT( EmptyString, "" );
#endif