height.hpp

 
#ifndef UFO_CONTAINER_TREE_PREDICATE_HEIGHT_HPP
#define UFO_CONTAINER_TREE_PREDICATE_HEIGHT_HPP
 
// UFO
#include <ufo/container/tree/predicate/filter.hpp>
#include <ufo/container/tree/predicate/predicate_interval.hpp>
 
namespace ufo::pred
{
namespace detail
{
struct Height {
    using value_type = int;
};
}  // namespace detail
 
template <bool Negated = false>
using Height = PredicateInterval<detail::Height, Negated>;
 
static constexpr inline Height<false> const height;
 
template <bool Negated>
struct Filter<Height<Negated>> {
    using Pred = Height<Negated>;
 
    template <class Tree>
    static constexpr void init(Pred&, Tree const&) noexcept
    {
    }
 
    template <class Value>
    [[nodiscard]] static constexpr bool returnableValue(Pred const&, Value const&) noexcept
    {
        return true;
    }
 
    template <class Tree>
    [[nodiscard]] static constexpr bool returnable(Pred const& p, Tree const& t,
                                                   typename Tree::Node const& n) noexcept
    {
        // Cast to int to prevent int to be promoted to unsigned
        int  height = static_cast<int>(t.height(n));
        bool ret    = p.min <= height && height <= p.max;
        if constexpr (Negated) {
            return !ret;
        } else {
            return ret;
        }
    }
 
    template <class Tree>
    [[nodiscard]] static constexpr bool traversable(Pred const& p, Tree const& t,
                                                    typename Tree::Node const& n) noexcept
    {
        // Cast to int to prevent int to be promoted to unsigned
        int height = static_cast<int>(t.height(n));
        if constexpr (Negated) {
            return 0 < p.min || p.max + 1 < height;
        } else {
            return p.min < height;
        }
    }
 
    template <class Tree>
    [[nodiscard]] static constexpr bool returnableRay(Pred const& p, Tree const& t,
                                                      typename Tree::Node const& n,
                                                      typename Tree::Ray const&) noexcept
    {
        return returnable(p, t, n);
    }
 
    template <class Tree>
    [[nodiscard]] static constexpr bool traversableRay(Pred const& p, Tree const& t,
                                                       typename Tree::Node const& n,
                                                       typename Tree::Ray const&) noexcept
    {
        return traversable(p, t, n);
    }
};
}  // namespace ufo::pred
 
#endif  // UFO_CONTAINER_TREE_PREDICATE_HEIGHT_HPP