Maybe.hpp

Go to the documentation of this file.

 
 
#ifndef ECSTASY_QUERY_MODIFIER_MAYBE_HPP_
#define ECSTASY_QUERY_MODIFIER_MAYBE_HPP_
 
#include <optional>
#include <type_traits>
 
#include "Modifier.hpp"
#include "ecstasy/query/concepts/Queryable.hpp"
#include "util/BitSet.hpp"
#include "util/meta/Traits.hpp"
#include "util/meta/add_optional.hpp"
 
namespace ecstasy::query::modifier
{
    template <Queryable Q, bool AutoLock = false>
    class Maybe : public Modifier<AutoLock> {
      public:
        using Internal = queryable_qualifiers_t<Q, AutoLock>;
 
        using Operands = util::meta::Traits<Q>;
 
        using QueryData = util::meta::add_optional_t<queryable_data_t<Q>>;
 
        Maybe(Q &internal) : _internal(internal)
        {
            adjustMask(getQueryableMask(internal).size());
        }
 
        [[nodiscard]] constexpr const util::BitSet &getMask() const noexcept
        {
            return _mask;
        }
 
        [[nodiscard]] constexpr QueryData getQueryData(size_t index)
        {
            if (index < getQueryableMask(_internal).size() && getQueryableMask(_internal)[index])
                return QueryData{getQueryableData(_internal, index)};
            return std::nullopt;
        }
 
        constexpr void adjustMask(size_t maxSize)
        {
            if (maxSize > _mask.size()) {
                _mask.resize(maxSize);
                _mask.setAll();
            }
        }
 
      private:
        Internal _internal;
        util::BitSet _mask;
    };
} // namespace ecstasy::query::modifier
 
#endif /* !ECSTASY_QUERY_MODIFIER_MAYBE_HPP_ */