knnGraphRangeIterator.h

/*
 This Source Code Form is subject to the terms of the Mozilla Public
 License, v. 2.0. If a copy of the MPL was not distributed with this
 file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
 
#pragma once
 
#include <cstddef>
 
namespace Ponca
{
    template <typename Traits>
    class KnnGraphRangeQuery;
 
    template <typename Traits>
    class KnnGraphRangeIterator
    {
    protected:
        friend class KnnGraphRangeQuery<Traits>;
        using Index = typename Traits::IndexType;
 
    public:
        // Tagged as an input iterator, because the increment logic is shared between iterators of the same queries.
        // Which makes the iterator not valid when duplicated (through postfix increment for example).
        using iterator_category = std::input_iterator_tag;
        using difference_type   = std::ptrdiff_t;
        using value_type        = Index;
        using pointer           = Index*;
        using reference         = const Index&;
 
        PONCA_MULTIARCH inline KnnGraphRangeIterator(KnnGraphRangeQuery<Traits>* query, Index index = Index(-1))
            : m_query(query), m_index(index)
        {
        }
 
    public:
        PONCA_MULTIARCH bool operator!=(const KnnGraphRangeIterator& other) const { return m_index != other.m_index; }
 
        PONCA_MULTIARCH bool operator==(const KnnGraphRangeIterator& other) const { return m_index == other.m_index; }
 
        PONCA_MULTIARCH inline KnnGraphRangeIterator& operator++()
        {
            m_query->advance(*this);
            return *this;
        }
 
        PONCA_MULTIARCH inline void operator++(value_type) { ++*this; }
 
        PONCA_MULTIARCH inline reference operator*() const { return const_cast<reference>(m_index); }
 
    protected:
        KnnGraphRangeQuery<Traits>* m_query{nullptr};
        value_type m_index{-1};
    };
 
} // namespace Ponca