mirror/meta_prog/unique.hpp

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#ifndef MIRROR_META_PROG_UNIQUE_1011291729_HPP
#define MIRROR_META_PROG_UNIQUE_1011291729_HPP


#include <mirror/meta_prog/range.hpp>

MIRROR_NAMESPACE_BEGIN
namespace mp {

#ifdef MIRROR_DOCUMENTATION_ONLY


template <class Range>
struct unique
{
    typedef UniqueRange type;
};
#endif

namespace aux {

// declaration of the internal helper for the unique meta-function
template <class UniqueRange, class TailRange>
struct unique_helper;

// specialization ending the filtering
template <typename ... UniqueP>
struct unique_helper<range<UniqueP...>, range<> >
{
    typedef range<UniqueP...> type;
};

// specialization of the unique_helper for non-empty
template <typename ... UniqueP, typename T, typename ... P>
struct unique_helper<range<UniqueP...>, range<T, P...> >
{
    typedef typename if_<
        typename empty<find<range<UniqueP...>, T> >::type,
        typename unique_helper<
            range<UniqueP..., T>,
            range<P...>
        >::type,
        typename unique_helper<
            range<UniqueP...>,
            range<P...>
        >::type
    >::type type;
};

} // namespace aux

// Implementation of the unique meta-function
template <typename ... P>
struct unique<range<P...> >
{
    // use the internale helper to remove the duplicities
    typedef typename aux::unique_helper<
        // at first the unique range is empty
        range<>,
        // and the remaining range is the range passes
        // as template parameter
        range<P...>
    >::type type;
};


} // namespace mp
MIRROR_NAMESPACE_END

#endif //include guard