index_from_pointer_iterator.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
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 * All rights reserved.                                                      *
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 * This program is free software; you can redistribute it and/or modify      *
 * it under the terms of the Mozilla Public License Version 2.0 as published *
 * by the Mozilla Foundation; either version 2 of the License, or            *
 * (at your option) any later version.                                       *
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 * This program is distributed in the hope that it will be useful,           *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the              *
 * Mozilla Public License Version 2.0                                        *
 * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
 ****************************************************************************/
 
#ifndef VCL_MESH_ITERATORS_COMPONENTS_INDEX_FROM_POINTER_ITERATOR_H
#define VCL_MESH_ITERATORS_COMPONENTS_INDEX_FROM_POINTER_ITERATOR_H
 
#include <vclib/types.h>
 
#include <iterator>
 
namespace vcl {
 
template<typename Iterator>
class IndexFromPointerIterator
{
    Iterator mIt;
 
public:
    using difference_type   = ptrdiff_t;
    using value_type        = uint;
    using reference         = const uint&;
    using pointer           = const uint*;
    using iterator_category = std::random_access_iterator_tag;
 
    IndexFromPointerIterator() = default;
 
    IndexFromPointerIterator(const Iterator& it) : mIt(it) {}
 
    value_type operator*() const
    {
        auto e = *mIt;
        if (e == nullptr) [[unlikely]]
            return UINT_NULL;
        else
            return e->index();
    }
 
    auto operator->() const { return FakePointerWithValue(**this); }
 
    bool operator==(const IndexFromPointerIterator& oi) const
    {
        return mIt == oi.mIt;
    }
 
    bool operator!=(const IndexFromPointerIterator& oi) const
    {
        return !(*this == oi);
    }
 
    IndexFromPointerIterator& operator++()
    {
        ++mIt;
        return *this;
    }
 
    IndexFromPointerIterator operator++(int)
    {
        auto it = *this;
        ++mIt;
        return it;
    }
 
    IndexFromPointerIterator& operator--()
    {
        --mIt;
        return *this;
    }
 
    IndexFromPointerIterator operator--(int)
    {
        auto it = *this;
        --mIt;
        return it;
    }
 
    IndexFromPointerIterator& operator+=(difference_type n)
    {
        mIt += n;
        return *this;
    }
 
    IndexFromPointerIterator& operator-=(difference_type n)
    {
        mIt -= n;
        return *this;
    }
 
    IndexFromPointerIterator operator+(difference_type n) const
    {
        auto it = *this;
        it += n;
        return it;
    }
 
    IndexFromPointerIterator operator-(difference_type n) const
    {
        auto it = *this;
        it -= n;
        return it;
    }
 
    difference_type operator-(const IndexFromPointerIterator& oi) const
    {
        return mIt - oi.mIt;
    }
 
    value_type operator[](difference_type i) { return *(*this + i); }
 
    bool operator<(const IndexFromPointerIterator& oi) const
    {
        return mIt < oi.mIt;
    }
 
    bool operator>(const IndexFromPointerIterator& oi) const
    {
        return mIt > oi.mIt;
    }
 
    bool operator<=(const IndexFromPointerIterator& oi) const
    {
        return mIt <= oi.mIt;
    }
 
    bool operator>=(const IndexFromPointerIterator& oi) const
    {
        return mIt >= oi.mIt;
    }
};
 
} // namespace vcl
 
#endif // VCL_MESH_ITERATORS_COMPONENTS_INDEX_FROM_POINTER_ITERATOR_H