lagoon/range/limit.hpp

Go to the documentation of this file.

#ifndef LAGOON_RANGE_LIMIT_1011291729_HPP
#define LAGOON_RANGE_LIMIT_1011291729_HPP

#include <lagoon/lagoon_fwd.hpp>
#include <cassert>

LAGOON_NAMESPACE_BEGIN
namespace aux {

template <class Range>
struct limited
{
private:
    Range range;
    size_t remaining;

public:
    limited(limited&& other)
     : range(std::move(other.range))
     , remaining(other.remaining)
    { }

    limited(const Range& rng, size_t limit)
     : range(rng)
     , remaining(limit)
    { }

    limited(Range&& rng, size_t limit)
     : range(std::forward(rng))
     , remaining(limit)
    { }

    inline bool empty(void) const
    {
        return (remaining == 0) || range.empty();
    }

    void step_front(void)
    {
        assert(remaining != 0);
        --remaining;
        range.step_front();
    }

    size_t leap_front(size_t amount)
    {
        if(amount > remaining)
            amount = remaining;
        return range.leap_front(amount);

    }

    inline auto front(void) const -> decltype(range.front())
    {
        assert(remaining != 0);
        return range.front();
    }

    friend inline bool same_position(
        const limited& a,
        const limited& b
    )
    {
        return same_position(a.range, b.range);
    }
};

} // namespace aux

#ifdef MIRROR_DOCUMENTATION_ONLY


template <class Range>
UnspecifiedRange limit(Range range, size_t count);
#else
template <class Range>
inline aux::limited<Range> limit(Range range, size_t count)
{
    return aux::limited<Range>(range, count);
}
#endif

LAGOON_NAMESPACE_END

#endif //include guard