forward-pointer-iterator.h

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Inkscape::Util::ForwardPointerIterator - wraps a simple pointer
 *                                          with various strategies
 *                                          to determine sequence
 *
 * Authors:
 *   MenTaLguY <mental@rydia.net>
 *
 * Copyright (C) 2004 MenTaLguY
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 */
 
#ifndef SEEN_INKSCAPE_UTIL_FORWARD_POINTER_ITERATOR_H
#define SEEN_INKSCAPE_UTIL_FORWARD_POINTER_ITERATOR_H
 
#include <iterator>
#include <cstddef>
#include "util/reference.h"
 
namespace Inkscape {
 
namespace Util {
 
template <typename BaseType, typename Strategy>
class ForwardPointerIterator;
 
template <typename BaseType, typename Strategy>
class ForwardPointerIterator<BaseType const, Strategy> {
public:
    typedef std::forward_iterator_tag iterator_category;
    typedef typename Traits::Reference<BaseType const>::LValue value_type;
    typedef std::ptrdiff_t difference_type;
    typedef typename Traits::Reference<BaseType const>::LValue reference;
    typedef typename Traits::Reference<BaseType const>::RValue const_reference;
    typedef typename Traits::Reference<BaseType const>::Pointer pointer;
 
    typedef ForwardPointerIterator<BaseType const, Strategy> Self;
 
    ForwardPointerIterator() = default;
    ForwardPointerIterator(pointer p) : _p(p) {}
 
    operator pointer() const { return _p; }
    reference operator*() const { return *_p; }
    pointer operator->() const { return _p; }
 
    bool operator==(Self const &other) const {
        return _p == other._p;
    }
    bool operator!=(Self const &other) const {
        return _p != other._p;
    }
 
    Self &operator++() {
        _p = Strategy::next(_p);
        return *this;
    }
    Self operator++(int) {
        Self old(*this);
        operator++();
        return old;
    }
 
    operator bool() const { return _p != nullptr; }
 
private:
    pointer _p;
};
 
template <typename BaseType, typename Strategy>
class ForwardPointerIterator
: public ForwardPointerIterator<BaseType const, Strategy>
{
public:
    typedef typename Traits::Reference<BaseType>::LValue value_type;
    typedef typename Traits::Reference<BaseType>::LValue reference;
    typedef typename Traits::Reference<BaseType>::RValue const_reference;
    typedef typename Traits::Reference<BaseType>::Pointer pointer;
 
    typedef ForwardPointerIterator<BaseType const, Strategy> Ancestor;
    typedef ForwardPointerIterator<BaseType, Strategy> Self;
 
    ForwardPointerIterator() : Ancestor() {}
    ForwardPointerIterator(pointer p) : Ancestor(p) {}
 
    operator pointer() const {
        return const_cast<pointer>(Ancestor::operator->());
    }
    reference operator*() const {
        return const_cast<reference>(Ancestor::operator*());
    }
    pointer operator->() const {
        return const_cast<pointer>(Ancestor::operator->());
    }
 
    Self &operator++() {
        Ancestor::operator++();
        return *this;
    }
    Self operator++(int) {
        Self old(*this);
        operator++();
        return old;
    }
};
 
}
 
}
 
#endif
/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :