// Copyright 2002 The Trustees of Indiana University.

// Use, modification and distribution is subject to the Boost Software 

// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at

// http://www.boost.org/LICENSE_1_0.txt)

//  Boost.MultiArray Library

//  Authors: Ronald Garcia

//           Jeremy Siek

//           Andrew Lumsdaine

//  See http://www.boost.org/libs/multi_array for documentation.

#ifndef ITERATOR_RG071801_HPP

#define ITERATOR_RG071801_HPP

//

// iterator.hpp - implementation of iterators for the

// multi-dimensional array class

//

#include "boost/multi_array/base.hpp"

#include "boost/iterator/iterator_facade.hpp"

#include "boost/mpl/aux_/msvc_eti_base.hpp"

#include <algorithm>

#include <cstddef>

#include <iterator>

namespace boost {

namespace detail {

namespace multi_array {

/////////////////////////////////////////////////////////////////////////

// iterator components

/////////////////////////////////////////////////////////////////////////

template <class T>

struct operator_arrow_proxy

{

  operator_arrow_proxy(T const& px) : value_(px) {}

  T* operator->() const { return &value_; }

  // This function is needed for MWCW and BCC, which won't call operator->

  // again automatically per 13.3.1.2 para 8

  operator T*() const { return &value_; }

  mutable T value_;

};

template <typename T, typename TPtr, typename NumDims, typename Reference>

class array_iterator;

template <typename T, typename TPtr, typename NumDims, typename Reference>

class array_iterator

  : public

    iterator_facade<

        array_iterator<T,TPtr,NumDims,Reference>

      , typename associated_types<T,NumDims>::value_type

      , boost::random_access_traversal_tag

      , Reference

    >

    , private

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)

      mpl::aux::msvc_eti_base<typename 

#endif 

          value_accessor_generator<T,NumDims>::type

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)

      >::type

#endif 

{

  friend class iterator_core_access;

  typedef detail::multi_array::associated_types<T,NumDims> access_t;

  typedef iterator_facade<

        array_iterator<T,TPtr,NumDims,Reference>

      , typename detail::multi_array::associated_types<T,NumDims>::value_type

      , boost::random_access_traversal_tag

      , Reference

    > facade_type;

  typedef typename access_t::index index;

  typedef typename access_t::size_type size_type;

#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS

  template <typename, typename, typename, typename>

    friend class array_iterator;

#else

 public:

#endif 

  index idx_;

  TPtr base_;

  const size_type* extents_;

  const index* strides_;

  const index* index_base_;

public:

  // Typedefs to circumvent ambiguities between parent classes

  typedef typename facade_type::reference reference;

  typedef typename facade_type::value_type value_type;

  typedef typename facade_type::difference_type difference_type;

  array_iterator() {}

  array_iterator(index idx, TPtr base, const size_type* extents,

                const index* strides,

                const index* index_base) :

    idx_(idx), base_(base), extents_(extents),

    strides_(strides), index_base_(index_base) { }

  template <typename OPtr, typename ORef>

  array_iterator(

      const array_iterator<T,OPtr,NumDims,ORef>& rhs

    , typename boost::enable_if_convertible<OPtr,TPtr>::type* = 0

  )

    : idx_(rhs.idx_), base_(rhs.base_), extents_(rhs.extents_),

    strides_(rhs.strides_), index_base_(rhs.index_base_) { }

  // RG - we make our own operator->

  operator_arrow_proxy<reference>

  operator->() const

  {

    return operator_arrow_proxy<reference>(this->dereference());

  }

  reference dereference() const

  {

    typedef typename value_accessor_generator<T,NumDims>::type accessor;

    return accessor::access(boost::type<reference>(),

                            idx_,

                            base_,

                            extents_,

                            strides_,

                            index_base_);

  }

  void increment() { ++idx_; }

  void decrement() { --idx_; }

  template <class IteratorAdaptor>

  bool equal(IteratorAdaptor& rhs) const {

    const std::size_t N = NumDims::value;

    return (idx_ == rhs.idx_) &&

      (base_ == rhs.base_) &&

      ( (extents_ == rhs.extents_) ||

        std::equal(extents_,extents_+N,rhs.extents_) ) &&

      ( (strides_ == rhs.strides_) ||

        std::equal(strides_,strides_+N,rhs.strides_) ) &&

      ( (index_base_ == rhs.index_base_) ||

        std::equal(index_base_,index_base_+N,rhs.index_base_) );

  }

  template <class DifferenceType>

  void advance(DifferenceType n) {

    idx_ += n;

  }

  template <class IteratorAdaptor>

  typename facade_type::difference_type

  distance_to(IteratorAdaptor& rhs) const {

    return rhs.idx_ - idx_;

  }

};

} // namespace multi_array

} // namespace detail

} // namespace boost

#endif // ITERATOR_RG071801_HPP