const_pointer_iterator.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
 *                                                                           *
 * All rights reserved.                                                      *
 *                                                                           *
 * 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.                                       *
 *                                                                           *
 * 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_MISC_ITERATORS_CONST_POINTER_ITERATOR_H
#define VCL_MISC_ITERATORS_CONST_POINTER_ITERATOR_H
 
#include <vclib/concepts/pointers.h>
#include <vclib/types/const_correctness.h>
 
#include <iterator>
 
namespace vcl {
 
template<typename It>
requires (IsAnyPointer<typename std::iterator_traits<It>::value_type>)
class ConstPointerIterator
{
    using Base = It;
 
    It mIt;
 
public:
    using difference_type = std::iterator_traits<It>::difference_type;
    using value_type =
        MakeConstPointerT<typename std::iterator_traits<It>::value_type>;
    using reference         = value_type&;
    using pointer           = value_type*;
    using iterator_category = std::iterator_traits<It>::iterator_category;
 
    ConstPointerIterator() = default;
 
    ConstPointerIterator(It it) : mIt(it) {}
 
    value_type operator*() const { return *mIt; }
 
    pointer operator->() const { return &(*mIt); }
 
    bool operator==(const ConstPointerIterator& oi) const
    {
        return mIt == oi.mIt;
    }
 
    bool operator!=(const ConstPointerIterator& oi) const
    {
        return mIt != oi.mIt;
    }
 
    ConstPointerIterator& operator++()
    {
        ++mIt;
        return *this;
    }
 
    ConstPointerIterator operator++(int)
    {
        ConstPointerIterator tmp = *this;
        ++mIt;
        return tmp;
    }
 
    ConstPointerIterator& operator--()
        requires (std::bidirectional_iterator<It>)
    {
        --mIt;
        return *this;
    }
 
    ConstPointerIterator operator--(int)
        requires (std::bidirectional_iterator<It>)
    {
        ConstPointerIterator tmp = *this;
        --mIt;
        return tmp;
    }
 
    ConstPointerIterator& operator+=(difference_type n)
        requires (std::random_access_iterator<It>)
    {
        mIt += n;
        return *this;
    }
 
    ConstPointerIterator operator+(difference_type n) const
        requires (std::random_access_iterator<It>)
    {
        return ConstPointerIterator(mIt + n);
    }
 
    friend ConstPointerIterator operator+(
        difference_type             n,
        const ConstPointerIterator& it)
        requires (std::random_access_iterator<It>)
    {
        return ConstPointerIterator(n + it.mIt);
    }
 
    ConstPointerIterator& operator-=(difference_type n)
        requires (std::random_access_iterator<It>)
    {
        mIt -= n;
        return *this;
    }
 
    ConstPointerIterator operator-(difference_type n) const
        requires (std::random_access_iterator<It>)
    {
        return ConstPointerIterator(mIt - n);
    }
 
    difference_type operator-(const ConstPointerIterator& oi) const
        requires (std::random_access_iterator<It>)
    {
        return mIt - oi.mIt;
    }
 
    value_type operator[](difference_type n) const
        requires (std::random_access_iterator<It>)
    {
        return mIt[n];
    }
};
 
} // namespace vcl
 
#endif // VCL_MISC_ITERATORS_CONST_POINTER_ITERATOR_H