boost/test/data/monomorphic/delayed.hpp
// (C) Copyright Raffi Enficiaud 2018.
// 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://www.boost.org/libs/test for the library home page.
//
/// @file
/// Defines a lazy/delayed dataset store
// ***************************************************************************
#ifndef BOOST_TEST_DATA_MONOMORPHIC_DELAYED_HPP_062018GER
#define BOOST_TEST_DATA_MONOMORPHIC_DELAYED_HPP_062018GER
// Boost.Test
#include <boost/test/data/config.hpp>
#include <boost/test/data/monomorphic/fwd.hpp>
#include <boost/test/data/index_sequence.hpp>
#include <boost/core/ref.hpp>
#include <algorithm>
#include <memory>
#include <boost/test/detail/suppress_warnings.hpp>
//____________________________________________________________________________//
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && \
!defined(BOOST_NO_CXX11_HDR_TUPLE)
namespace boost {
namespace unit_test {
namespace data {
namespace monomorphic {
// ************************************************************************** //
// ************** delayed_dataset ************** //
// ************************************************************************** //
/// Delayed dataset
///
/// This dataset holds another dataset that is instanciated on demand. It is
/// constructed with the @c data::make_delayed<dataset_t>(arg1,....) instead of the
/// @c data::make.
template <class dataset_t, class ...Args>
class delayed_dataset
{
public:
enum { arity = dataset_t::arity };
using iterator = decltype(std::declval<dataset_t>().begin());
delayed_dataset(Args... args)
: m_args(std::make_tuple(std::forward<Args>(args)...))
{}
// Mostly for VS2013
delayed_dataset(delayed_dataset&& b)
: m_args(std::move(b.m_args))
, m_dataset(std::move(b.m_dataset))
{}
boost::unit_test::data::size_t size() const {
return this->get().size();
}
// iterator
iterator begin() const {
return this->get().begin();
}
private:
dataset_t& get() const {
if(!m_dataset) {
m_dataset = create(boost::unit_test::data::index_sequence_for<Args...>());
}
return *m_dataset;
}
template<std::size_t... I>
std::unique_ptr<dataset_t>
create(boost::unit_test::data::index_sequence<I...>) const
{
return std::unique_ptr<dataset_t>{new dataset_t(std::get<I>(m_args)...)};
}
std::tuple<typename std::decay<Args>::type...> m_args;
mutable std::unique_ptr<dataset_t> m_dataset;
};
//____________________________________________________________________________//
//! A lazy/delayed dataset is a dataset.
template <class dataset_t, class ...Args>
struct is_dataset< delayed_dataset<dataset_t, Args...> > : boost::mpl::true_ {};
//____________________________________________________________________________//
} // namespace monomorphic
//! Delayed dataset instanciation
template<class dataset_t, class ...Args>
inline typename std::enable_if<
monomorphic::is_dataset< dataset_t >::value,
monomorphic::delayed_dataset<dataset_t, Args...>
>::type
make_delayed(Args... args)
{
return monomorphic::delayed_dataset<dataset_t, Args...>( std::forward<Args>(args)... );
}
} // namespace data
} // namespace unit_test
} // namespace boost
#endif
#include <boost/test/detail/enable_warnings.hpp>
#endif // BOOST_TEST_DATA_MONOMORPHIC_DELAYED_HPP_062018GER