//---------------------------------------------------------------------------//
|
// Copyright (c) 2013 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_FIELD_HPP
|
#define BOOST_COMPUTE_FUNCTIONAL_FIELD_HPP
|
|
#include <string>
|
|
namespace boost {
|
namespace compute {
|
namespace detail {
|
|
template<class T, class Arg>
|
struct invoked_field
|
{
|
typedef T result_type;
|
|
invoked_field(const Arg &arg, const std::string &field)
|
: m_arg(arg),
|
m_field(field)
|
{
|
}
|
|
Arg m_arg;
|
std::string m_field;
|
};
|
|
} // end detail namespace
|
|
/// Returns the named field from a value.
|
///
|
/// The template-type \c T specifies the field's value type. Note
|
/// that the value type must match the actual type of the field
|
/// otherwise runtime compilation or logic errors may occur.
|
///
|
/// For example, to access the \c second field in a
|
/// \c std::pair<int, float> object:
|
/// \code
|
/// field<float>("second");
|
/// \endcode
|
///
|
/// This can also be used with vector types to access individual
|
/// components as well as perform swizzle operations.
|
///
|
/// For example, to access the first and third components of an
|
/// \c int vector type (e.g. \c int4):
|
/// \code
|
/// field<int2_>("xz");
|
/// \endcode
|
///
|
/// \see \ref get "get<N>"
|
template<class T>
|
class field
|
{
|
public:
|
/// Result type.
|
typedef T result_type;
|
|
/// Creates a new field functor with \p field.
|
field(const std::string &field)
|
: m_field(field)
|
{
|
}
|
|
/// \internal_
|
template<class Arg>
|
detail::invoked_field<T, Arg> operator()(const Arg &arg) const
|
{
|
return detail::invoked_field<T, Arg>(arg, m_field);
|
}
|
|
private:
|
std::string m_field;
|
};
|
|
} // end compute namespace
|
} // end boost namespace
|
|
#endif // BOOST_COMPUTE_FUNCTIONAL_FIELD_HPP
|
