Traits.h

#pragma once
 
#include "IterValue.h"
#include "SizeHint.h"
 
namespace CXXIter::trait {
 
    // ################################################################################################
    // ITERATOR TRAITS
    // ################################################################################################
 
    template<typename T>
    struct Iterator {
        using Self = trait::Iterator<T>;
        using Item = void;
 
        static constexpr inline IterValue<Item> next(Self& self) = delete;
 
        static constexpr inline SizeHint sizeHint(const Self& self) = delete;
 
        static constexpr inline size_t advanceBy(Self& self, size_t n) = delete;
    };
 
    template<typename T>
    struct ExactSizeIterator {
        static constexpr inline size_t size(const typename trait::Iterator<T>::Self& self) = delete;
    };
 
    template<typename T>
    struct ContiguousMemoryIterator {
        using ItemPtr = std::add_pointer_t<std::remove_reference_t<typename Iterator<T>::Item>>;
        static constexpr inline ItemPtr currentPtr(typename trait::Iterator<T>::Self& self) = delete;
    };
 
    template<typename T>
    struct DoubleEndedIterator {
        using Self = typename trait::Iterator<T>::Self;
 
        static constexpr inline IterValue<typename Iterator<T>::Item> nextBack(Self& self) = delete;
    };
 
 
    // ################################################################################################
    // SOURCE TRAITS
    // ################################################################################################
 
    template<typename TContainer> struct Source {
        using Item = typename TContainer::value_type;
        using ItemRef = typename TContainer::reference;
        using ItemConstRef = typename TContainer::const_reference;
 
        struct IteratorState {
            typename TContainer::iterator left;
            typename TContainer::iterator right;
        };
 
        struct ConstIteratorState {
            typename TContainer::const_iterator left;
            typename TContainer::const_iterator right;
        };
 
        static constexpr inline SizeHint sizeHint(const TContainer& container) { return SizeHint(container.size(), container.size()); }
 
        static constexpr inline IteratorState initIterator(TContainer& container) { return {container.begin(), container.end()}; }
        static constexpr inline ConstIteratorState initIterator(const TContainer& container) { return {container.begin(), container.end()}; }
 
        static constexpr inline bool hasNext([[maybe_unused]] TContainer& container, IteratorState& iter) { return (iter.left != iter.right); }
        static constexpr inline bool hasNext([[maybe_unused]] const TContainer& container, ConstIteratorState& iter) { return (iter.left != iter.right); }
 
        static constexpr inline ItemRef next([[maybe_unused]] TContainer& container, IteratorState& iter) { return (*iter.left++); }
        static constexpr inline ItemConstRef next([[maybe_unused]] const TContainer& container, ConstIteratorState& iter) { return (*iter.left++); }
 
        static constexpr inline ItemRef peekNext([[maybe_unused]] TContainer& container, IteratorState& iter) { return (*iter.left); }
        static constexpr inline ItemConstRef peekNext([[maybe_unused]] const TContainer& container, ConstIteratorState& iter) { return (*iter.left); }
 
        static constexpr inline size_t skipN([[maybe_unused]] const TContainer& container, IteratorState& iter, size_t n) {
            size_t skipN = std::min(n, static_cast<size_t>(std::distance(iter.left, iter.right)));
            iter.left += skipN;
            return skipN;
        }
        static constexpr inline size_t skipN([[maybe_unused]] const TContainer& container, ConstIteratorState& iter, size_t n) {
            size_t skipN = std::min(n, static_cast<size_t>(std::distance(iter.left, iter.right)));
            iter.left += skipN;
            return skipN;
        }
 
        static constexpr inline ItemRef nextBack([[maybe_unused]] TContainer& container, IteratorState& iter) { return (*--iter.right); }
        static constexpr inline ItemConstRef nextBack([[maybe_unused]] const TContainer& container, ConstIteratorState& iter) { return (*--iter.right); }
 
        static constexpr inline size_t skipNBack([[maybe_unused]] const TContainer& container, IteratorState& iter, size_t n) {
            size_t skipN = std::min(n, static_cast<size_t>(std::distance(iter.left, iter.right)));
            iter.right -= skipN;
            return skipN;
        }
        static constexpr inline size_t skipNBack([[maybe_unused]] const TContainer& container, ConstIteratorState& iter, size_t n) {
            size_t skipN = std::min(n, static_cast<size_t>(std::distance(iter.left, iter.right)));
            iter.right -= skipN;
            return skipN;
        }
    //}@
 
    };
 
}