IndexedElementIterator.hpp

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/* 
 * IndexedElementIterator.hpp 
 *
 * This file is part of the Chemical Data Processing Toolkit
 *
 * Copyright (C) 2003 Thomas Seidel <thomas.seidel@univie.ac.at>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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 GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; see the file COPYING. If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 
#ifndef CDPL_UTIL_INDEXEDELEMENTITERATOR_HPP
#define CDPL_UTIL_INDEXEDELEMENTITERATOR_HPP
 
#include <cstddef>
 
#include <boost/iterator/iterator_facade.hpp>
 
 
namespace CDPL
{
 
    namespace Util
    {
 
        template <typename ValueType, typename AccessFunc, typename IndexType = std::size_t>
        class IndexedElementIterator : public boost::iterator_facade<IndexedElementIterator<ValueType, AccessFunc, IndexType>,
                                                                     ValueType, boost::random_access_traversal_tag>
        {
 
            typedef typename boost::iterator_facade<IndexedElementIterator<ValueType, AccessFunc, IndexType>,
                                                    ValueType,
                                                    boost::random_access_traversal_tag>::difference_type DifferenceType;
 
          public:
            template <typename ValueType2, typename AccessFunc2, typename IndexType2>
            IndexedElementIterator(const IndexedElementIterator<ValueType2, AccessFunc2, IndexType2>& it):
                accessFunc(it.getAccessFunc()), index(it.getIndex())
            {}
 
            IndexedElementIterator(const AccessFunc& access_func, IndexType start_idx):
                accessFunc(access_func), index(start_idx) {}
 
            const AccessFunc& getAccessFunc() const;
 
            IndexType getIndex() const;
 
          private:
            friend class boost::iterator_core_access;
 
            void increment();
            void decrement();
            void advance(DifferenceType);
 
            template <typename ValueType2, typename AccessFunc2, typename IndexType2>
            DifferenceType distance_to(const IndexedElementIterator<ValueType2, AccessFunc2, IndexType2>&) const;
 
            template <typename ValueType2, typename AccessFunc2, typename IndexType2>
            bool equal(const IndexedElementIterator<ValueType2, AccessFunc2, IndexType2>&) const;
 
            ValueType& dereference() const;
 
            AccessFunc accessFunc;
            IndexType  index;
        };
    } // namespace Util
} // namespace CDPL
 
 
// Implementation
 
template <typename ValueType, typename AccessFunc, typename IndexType>
IndexType CDPL::Util::IndexedElementIterator<ValueType, AccessFunc, IndexType>::getIndex() const
{
    return index;
}
 
template <typename ValueType, typename AccessFunc, typename IndexType>
const AccessFunc& CDPL::Util::IndexedElementIterator<ValueType, AccessFunc, IndexType>::getAccessFunc() const
{
    return accessFunc;
}
 
template <typename ValueType, typename AccessFunc, typename IndexType>
void CDPL::Util::IndexedElementIterator<ValueType, AccessFunc, IndexType>::increment()
{
    index++;
}
 
template <typename ValueType, typename AccessFunc, typename IndexType>
void CDPL::Util::IndexedElementIterator<ValueType, AccessFunc, IndexType>::decrement()
{
    index--;
}
 
template <typename ValueType, typename AccessFunc, typename IndexType>
void CDPL::Util::IndexedElementIterator<ValueType, AccessFunc, IndexType>::advance(DifferenceType diff)
{
    index += diff;
}
 
template <typename ValueType, typename AccessFunc, typename IndexType>
template <typename ValueType2, typename AccessFunc2, typename IndexType2>
typename CDPL::Util::IndexedElementIterator<ValueType, AccessFunc, IndexType>::DifferenceType
CDPL::Util::IndexedElementIterator<ValueType, AccessFunc, IndexType>::distance_to(const IndexedElementIterator<ValueType2, AccessFunc2, IndexType2>& it) const
{
    return (DifferenceType(it.index) - DifferenceType(index));
}
 
template <typename ValueType, typename AccessFunc, typename IndexType>
template <typename ValueType2, typename AccessFunc2, typename IndexType2>
bool CDPL::Util::IndexedElementIterator<ValueType, AccessFunc, IndexType>::equal(const IndexedElementIterator<ValueType2, AccessFunc2, IndexType2>& it) const
{
    return (index == it.index && accessFunc == it.accessFunc);
}
 
template <typename ValueType, typename AccessFunc, typename IndexType>
ValueType& CDPL::Util::IndexedElementIterator<ValueType, AccessFunc, IndexType>::dereference() const
{
    return accessFunc(index);
}
 
#endif // CDPL_UTIL_INDEXEDELEMENTITERATOR_HPP