value_iterator.hpp

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/*
    Copyright 2005-2007 Adobe Systems Incorporated
    Distributed under the MIT License (see accompanying file LICENSE_1_0_0.txt
    or a copy at http://stlab.adobe.com/licenses.html)
*/

/*************************************************************************************************/

#ifndef ADOBE_ITERATOR_VALUE_ITERATOR_HPP
#define ADOBE_ITERATOR_VALUE_ITERATOR_HPP

#include <adobe/config.hpp>

#include <adobe/functional.hpp>

#include <functional>
#include <iterator>
#include <cassert>

/*************************************************************************************************/

namespace adobe {

/*************************************************************************************************/



template <typename I,                // I models Incrementable    
          typename F = identity<I> > // F models UnaryFunction 
class value_iterator
{
public:
    typedef typename F::result_type   value_type;
    typedef value_type*               pointer;
    typedef value_type&               reference;
    typedef ptrdiff_t                 difference_type;
    typedef std::forward_iterator_tag iterator_category;

private:
    I i;
    F f;

public:
    value_iterator()
    { }

    value_iterator(const I& x, const F& y) :
        i(x), f(y)
    { }

    value_iterator& operator++()
    {
        ++i;
        return *this;
    }

    value_iterator operator++(int)
    {
        value_iterator tmp = *this;

        ++*this;

        return tmp;
    }

    const value_type& operator*() const
    {
        return f(i);
    }

    value_type operator*()
    {
        return f(i);
    }

    friend bool operator==(const value_iterator& a, const value_iterator& b)
    {
        // assert(a.f == b.f);

        return a.i == b.i;
    }

    friend bool operator!=(const value_iterator& a, const value_iterator& b)
    {
        return !(a == b);
    }
};


/*************************************************************************************************/

} // namespace adobe

/*************************************************************************************************/

#endif
// ADOBE_ITERATOR_DISTANCE_HPP