65 lines
1.6 KiB
C++
65 lines
1.6 KiB
C++
|
//---------------------------------------------------------------------------//
|
||
|
|
// Copyright (c) 2013-2014 Kyle Lutz <kyle.r.lutz@gmail.com>
|
||
|
|
//
|
||
|
|
// Distributed under the Boost Software License, Version 1.0
|
||
|
|
// See accompanying file LICENSE_1_0.txt or copy at
|
||
|
|
// http://www.boost.org/LICENSE_1_0.txt
|
||
|
|
//
|
||
|
|
// See http://boostorg.github.com/compute for more information.
|
||
|
|
//---------------------------------------------------------------------------//
|
||
|
|
|
||
|
|
#ifndef BOOST_COMPUTE_FUNCTIONAL_IDENTITY_HPP
|
||
|
|
#define BOOST_COMPUTE_FUNCTIONAL_IDENTITY_HPP
|
||
|
|
|
||
|
|
namespace boost {
|
||
|
|
namespace compute {
|
||
|
|
namespace detail {
|
||
|
|
|
||
|
|
template<class T, class Arg>
|
||
|
|
struct invoked_identity
|
||
|
|
{
|
||
|
|
typedef T result_type;
|
||
|
|
|
||
|
|
invoked_identity(const Arg &arg)
|
||
|
|
: m_arg(arg)
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
Arg m_arg;
|
||
|
|
};
|
||
|
|
|
||
|
|
} // end detail namespace
|
||
|
|
|
||
|
|
/// Identity function which simply returns its input.
|
||
|
|
///
|
||
|
|
/// For example, to directly copy values using the transform() algorithm:
|
||
|
|
/// \code
|
||
|
|
/// transform(input.begin(), input.end(), output.begin(), identity<int>(), queue);
|
||
|
|
/// \endcode
|
||
|
|
///
|
||
|
|
/// \see \ref as "as<T>", \ref convert "convert<T>"
|
||
|
|
template<class T>
|
||
|
|
class identity
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
/// Identity function result type.
|
||
|
|
typedef T result_type;
|
||
|
|
|
||
|
|
/// Creates a new identity function.
|
||
|
|
identity()
|
||
|
|
{
|
||
|
|
}
|
||
|
|
|
||
|
|
/// \internal_
|
||
|
|
template<class Arg>
|
||
|
|
detail::invoked_identity<T, Arg> operator()(const Arg &arg) const
|
||
|
|
{
|
||
|
|
return detail::invoked_identity<T, Arg>(arg);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
} // end compute namespace
|
||
|
|
} // end boost namespace
|
||
|
|
|
||
|
|
#endif // BOOST_COMPUTE_FUNCTIONAL_IDENTITY_HPP
|