array_view_base.h

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// -*- mode: c++; tab-width: 4; indent-tabs-mode: t; eval: (progn (c-set-style "stroustrup") (c-set-offset 'innamespace 0)); -*-
// vi:set ts=4 sts=4 sw=4 noet :
// Copyright 2012, The TPIE development team
// 
// This file is part of TPIE.
// 
// TPIE 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 3 of the License, or (at your
// option) any later version.
// 
// TPIE 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 TPIE.  If not, see <http://www.gnu.org/licenses/>

#ifndef __ARRAY_VIEW_BASE_H__
#define  __ARRAY_VIEW_BASE_H__


#include <boost/iterator/iterator_facade.hpp>
#include <cassert>
namespace tpie {


template <typename T>
class array_view_base {
private:
    T * m_start;
    T * m_end;
public:
    class iterator: public boost::iterator_facade<iterator, T, boost::random_access_traversal_tag> {
    private:
        friend class array_view_base;
        friend class boost::iterator_core_access;
        explicit iterator(T * e): elm(e) {}
        inline T & dereference() const {return * elm;}
        inline bool equal(iterator const& o) const {return elm == o.elm;}
        inline void increment() {++elm;}
        inline void decrement() {--elm;}
        inline void advance(size_t n) {elm += n;}
        inline ptrdiff_t distance_to(iterator const & o) const {return o.elm - elm;}
        T * elm;
    public:
        iterator(): elm(0) {};
    };


    array_view_base(T * start, T * end): m_start(start), m_end(end) {}

    typedef T value_type;

    iterator find(size_t idx) const throw () {
        assert(idx <= size());
        return iterator(m_start + idx);
    }

    T & at(size_t i) const throw() {
        assert(i < size());
        return *find(i);
    }

    inline bool empty() const {return m_end == m_start;}

    inline size_t size() const {return m_end - m_start;}

    inline T & operator[](size_t i) const {
        assert(i < size());
        return at(i);
    }

    inline bool operator==(const array_view_base & other) const {
        if (size() != other.size()) return false;
        for (size_t i=0; i < size(); ++i) if (at(i) != other.at(i)) return false;
        return true;
    }

    inline bool operator!=(const array_view_base & other) const {
        if (size() != other.size()) return true;
        for (size_t i=0; i< size(); ++i) if (at(i) != other.at(i)) return true;
        return false;
    }

    inline iterator begin() const {return iterator(m_start);}

    inline iterator end() const {return iterator(m_end);}

    inline T & front() const {return *m_start;}

    inline T & back() const {return *(m_end-1);}
};

} //namespace tpie

#endif //__ARRAY_VIEW_BASE_H__