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// SelectArg.hh for FbTk
// Copyright (c) 2010 Fluxbox Team (fluxgen at fluxbox dot org)
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
#ifndef FBTK_STLUTIL_SELECT_ARG_HH
#define FBTK_STLUTIL_SELECT_ARG_HH
#include "STLUtil.hh"
namespace FbTk {
namespace STLUtil {
/**
* Selects a single argument from a maximum set of three arguments at compile time.
* For example:
* \begincode
* SelectArg<0>()( 10, 20, "hello" ); // returns first argument ( 10 )
* SelectArg<1>()( 10, "hello", 30 ); // returns second argument ( "hello" )
* SelectArg<2>()( 10, "hello", 30 ); // returns third argument ( 30 )
* \endcode
*
* The selection of argument 1 and 2 can return the last argument if the
* arguments are less or equal to two. For instance:
* \begincode
* SelectArg<1>()(10); // returns 10
* SelectArg<2>()(10, 20); // returns 20
* SelectArg<2>()(10); // returns 10
* \endcode
*/
template < int N >
struct SelectArg {
template <typename Type1, typename Type2>
typename IfThenElse<N==0, Type1, Type2>::ResultType& operator ()(Type1& a, Type2& b){
return IfThenElse<N==0, Type1, Type2>()(a, b);
}
template <typename Type1, typename Type2, typename Type3>
typename IfThenElse<N==0, Type1,
typename IfThenElse<N==1, Type2, Type3>::ResultType>::ResultType&
operator () (Type1& a, Type2& b, Type3& c) {
return IfThenElse<N==0, Type1,
typename IfThenElse<N==1, Type2, Type3>::ResultType>()
(a, IfThenElse<N==1, Type2, Type3>() (b, c) );
}
template < typename Type1 >
Type1 operator() (Type1 a) {
return a;
}
};
} // end namespace STLUtil
} // end namespace FbTk
#endif // FBTK_STLUTIL_SELECT_ARG_HH
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