// 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 BOOST_MULTI_ARRAY_VIEW_RG071301_HPP

#define BOOST_MULTI_ARRAY_VIEW_RG071301_HPP

//

// view.hpp - code for creating "views" of array data.

//

#include "boost/multi_array/base.hpp"

#include "boost/multi_array/concept_checks.hpp"

#include "boost/multi_array/iterator.hpp"

#include "boost/multi_array/storage_order.hpp"

#include "boost/multi_array/subarray.hpp"

#include "boost/multi_array/algorithm.hpp"

#include "boost/type_traits/is_integral.hpp"

#include "boost/array.hpp"

#include "boost/limits.hpp"

#include <algorithm>

#include <cstddef>

#include <functional>

#include <numeric>

namespace boost {

namespace detail {

namespace multi_array {

// TPtr = const T* defaulted in base.hpp

template <typename T, std::size_t NumDims, typename TPtr>

class const_multi_array_view :

    public boost::detail::multi_array::multi_array_impl_base<T,NumDims>

{

  typedef boost::detail::multi_array::multi_array_impl_base<T,NumDims> super_type;

public: 

  typedef typename super_type::value_type value_type;

  typedef typename super_type::const_reference const_reference;

  typedef typename super_type::const_iterator const_iterator;

  typedef typename super_type::const_reverse_iterator const_reverse_iterator;

  typedef typename super_type::element element;

  typedef typename super_type::size_type size_type;

  typedef typename super_type::difference_type difference_type;

  typedef typename super_type::index index;

  typedef typename super_type::extent_range extent_range;

  // template typedefs

  template <std::size_t NDims>

  struct const_array_view {

    typedef boost::detail::multi_array::const_multi_array_view<T,NDims> type;

  };

  template <std::size_t NDims>

  struct array_view {

    typedef boost::detail::multi_array::multi_array_view<T,NDims> type;

  };

  template <typename OPtr>

  const_multi_array_view(const 

                         const_multi_array_view<T,NumDims,OPtr>& other) :

    base_(other.base_), origin_offset_(other.origin_offset_),

    num_elements_(other.num_elements_), extent_list_(other.extent_list_),

    stride_list_(other.stride_list_), index_base_list_(other.index_base_list_)

  { }

  template <class BaseList>

#ifdef BOOST_NO_SFINAE

  void

#else

  typename

  disable_if<typename boost::is_integral<BaseList>::type,void >::type

#endif

  reindex(const BaseList& values) {

    boost::function_requires<

      detail::multi_array::CollectionConcept<BaseList> >();

    boost::detail::multi_array::

      copy_n(values.begin(),num_dimensions(),index_base_list_.begin());

    origin_offset_ =

      this->calculate_indexing_offset(stride_list_,index_base_list_);

  }

  void reindex(index value) {

    index_base_list_.assign(value);

    origin_offset_ =

      this->calculate_indexing_offset(stride_list_,index_base_list_);

  }

  size_type num_dimensions() const { return NumDims; }

  size_type size() const { return extent_list_.front(); }

  size_type max_size() const { return num_elements(); }

  bool empty() const { return size() == 0; }

  const size_type* shape() const {

    return extent_list_.data();

  }

  const index* strides() const {

    return stride_list_.data();

  }

  const T* origin() const { return base_+origin_offset_; }

  size_type num_elements() const { return num_elements_; }

  const index* index_bases() const {

    return index_base_list_.data();

  }

  template <typename IndexList>

  const element& operator()(IndexList indices) const {

    boost::function_requires<

      detail::multi_array::CollectionConcept<IndexList> >();

    return super_type::access_element(boost::type<const element&>(),

                                      indices,origin(),

                                      shape(),strides(),index_bases());

  }

  // Only allow const element access

  const_reference operator[](index idx) const {

    return super_type::access(boost::type<const_reference>(),

                              idx,origin(),

                              shape(),strides(),

                              index_bases());

  }

  // see generate_array_view in base.hpp

#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300

  template <int NDims>

#else

  template <int NumDims, int NDims> // else ICE

#endif // BOOST_MSVC

  typename const_array_view<NDims>::type 

  operator[](const boost::detail::multi_array::

             index_gen<NumDims,NDims>& indices)

    const {

    typedef typename const_array_view<NDims>::type return_type;

    return

      super_type::generate_array_view(boost::type<return_type>(),

                                      indices,

                                      shape(),

                                      strides(),

                                      index_bases(),

                                      origin());

  }

  const_iterator begin() const {

    return const_iterator(*index_bases(),origin(),

                          shape(),strides(),index_bases());

  }

  const_iterator end() const {

    return const_iterator(*index_bases()+(index)*shape(),origin(),

                          shape(),strides(),index_bases());

  }

  const_reverse_iterator rbegin() const {

    return const_reverse_iterator(end());

  }

  const_reverse_iterator rend() const {

    return const_reverse_iterator(begin());

  }

  template <typename OPtr>

  bool operator==(const

                  const_multi_array_view<T,NumDims,OPtr>& rhs)

    const {

    if(std::equal(extent_list_.begin(),

                  extent_list_.end(),

                  rhs.extent_list_.begin()))

      return std::equal(begin(),end(),rhs.begin());

    else return false;

  }

  template <typename OPtr>

  bool operator<(const

                 const_multi_array_view<T,NumDims,OPtr>& rhs)

    const {

    return std::lexicographical_compare(begin(),end(),rhs.begin(),rhs.end());

  }

  template <typename OPtr>

  bool operator!=(const

                  const_multi_array_view<T,NumDims,OPtr>& rhs)

    const {

    return !(*this == rhs);

  }

  template <typename OPtr>

  bool operator>(const

                 const_multi_array_view<T,NumDims,OPtr>& rhs)

    const {

    return rhs < *this;

  }

  template <typename OPtr>

  bool operator<=(const

                 const_multi_array_view<T,NumDims,OPtr>& rhs)

    const {

    return !(*this > rhs);

  }

  template <typename OPtr>

  bool operator>=(const

                 const_multi_array_view<T,NumDims,OPtr>& rhs)

    const {

    return !(*this < rhs);

  }

#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS

protected:

  template <typename,std::size_t> friend class multi_array_impl_base;

  template <typename,std::size_t,typename> friend class const_multi_array_view;

#else

public: // should be protected

#endif

  // This constructor is used by multi_array_impl_base::generate_array_view

  // to create strides  

  template <typename ExtentList, typename Index>

  explicit const_multi_array_view(TPtr base,

                           const ExtentList& extents,

                           const boost::array<Index,NumDims>& strides): 

    base_(base), origin_offset_(0) {

    index_base_list_.assign(0);

    // Get the extents and strides

    boost::detail::multi_array::

      copy_n(extents.begin(),NumDims,extent_list_.begin());

    boost::detail::multi_array::

      copy_n(strides.begin(),NumDims,stride_list_.begin());

    // Calculate the array size

    num_elements_ = std::accumulate(extent_list_.begin(),extent_list_.end(),

                            size_type(1),std::multiplies<size_type>());

#if 0

    assert(num_elements_ != 0);

#endif

  }

  typedef boost::array<size_type,NumDims> size_list;

  typedef boost::array<index,NumDims> index_list;

  TPtr base_;

  index origin_offset_;

  size_type num_elements_;

  size_list extent_list_;

  index_list stride_list_;

  index_list index_base_list_;

private:

  // const_multi_array_view cannot be assigned to (no deep copies!)

  const_multi_array_view& operator=(const const_multi_array_view& other);

};

template <typename T, std::size_t NumDims>

class multi_array_view :

  public const_multi_array_view<T,NumDims,T*>

{

  typedef const_multi_array_view<T,NumDims,T*> super_type;

public: 

  typedef typename super_type::value_type value_type;

  typedef typename super_type::reference reference;

  typedef typename super_type::iterator iterator;

  typedef typename super_type::reverse_iterator reverse_iterator;

  typedef typename super_type::const_reference const_reference;

  typedef typename super_type::const_iterator const_iterator;

  typedef typename super_type::const_reverse_iterator const_reverse_iterator;

  typedef typename super_type::element element;

  typedef typename super_type::size_type size_type;

  typedef typename super_type::difference_type difference_type;

  typedef typename super_type::index index;

  typedef typename super_type::extent_range extent_range;

  // template typedefs

  template <std::size_t NDims>

  struct const_array_view {

    typedef boost::detail::multi_array::const_multi_array_view<T,NDims> type;

  };

  template <std::size_t NDims>

  struct array_view {

    typedef boost::detail::multi_array::multi_array_view<T,NDims> type;

  };

  // Assignment from other ConstMultiArray types.

  template <typename ConstMultiArray>

  multi_array_view& operator=(const ConstMultiArray& other) {

    function_requires< 

      boost::detail::multi_array::

      ConstMultiArrayConcept<ConstMultiArray,NumDims> >();

    // make sure the dimensions agree

    assert(other.num_dimensions() == this->num_dimensions());

    assert(std::equal(other.shape(),other.shape()+this->num_dimensions(),

                      this->shape()));

    // iterator-based copy

    std::copy(other.begin(),other.end(),begin());

    return *this;

  }

  multi_array_view& operator=(const multi_array_view& other) {

    if (&other != this) {

      // make sure the dimensions agree

      assert(other.num_dimensions() == this->num_dimensions());

      assert(std::equal(other.shape(),other.shape()+this->num_dimensions(),

                        this->shape()));

      // iterator-based copy

      std::copy(other.begin(),other.end(),begin());

    }

    return *this;

  }

  element* origin() { return this->base_+this->origin_offset_; }

  template <class IndexList>

  element& operator()(const IndexList& indices) {

    boost::function_requires<

      detail::multi_array::CollectionConcept<IndexList> >();

    return super_type::access_element(boost::type<element&>(),

                                      indices,origin(),

                                      this->shape(),this->strides(),

                                      this->index_bases());

  }

  reference operator[](index idx) {

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

                              idx,origin(),

                              this->shape(),this->strides(),

                              this->index_bases());

  }

  // see generate_array_view in base.hpp

#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300

  template <int NDims>

#else

  template <int NumDims, int NDims> // else ICE

#endif // BOOST_MSVC

  typename array_view<NDims>::type 

  operator[](const boost::detail::multi_array::

             index_gen<NumDims,NDims>& indices) {

    typedef typename array_view<NDims>::type return_type;

    return

      super_type::generate_array_view(boost::type<return_type>(),

                                      indices,

                                      this->shape(),

                                      this->strides(),

                                      this->index_bases(),

                                      origin());

  }

  iterator begin() {

    return iterator(*this->index_bases(),origin(),

                    this->shape(),this->strides(),

                    this->index_bases());

  }

  iterator end() {

    return iterator(*this->index_bases()+(index)*this->shape(),origin(),

                    this->shape(),this->strides(),

                    this->index_bases());

  }

  reverse_iterator rbegin() {

    return reverse_iterator(end());

  }

  reverse_iterator rend() {

    return reverse_iterator(begin());

  }

  // Using declarations don't seem to work for g++

  // These are the proxies to work around this.

  const element* origin() const { return super_type::origin(); }

  template <class IndexList>

  const element& operator()(const IndexList& indices) const {

    boost::function_requires<

      detail::multi_array::CollectionConcept<IndexList> >();

    return super_type::operator()(indices);

  }

  const_reference operator[](index idx) const {

    return super_type::operator[](idx);

  }

  // see generate_array_view in base.hpp

#if !defined(BOOST_MSVC) || BOOST_MSVC > 1300

  template <int NDims>

#else

  template <int NumDims, int NDims> // else ICE

#endif // BOOST_MSVC

  typename const_array_view<NDims>::type 

  operator[](const boost::detail::multi_array::

             index_gen<NumDims,NDims>& indices)

    const {

    return super_type::operator[](indices);

  }

  const_iterator begin() const {

    return super_type::begin();

  }

  const_iterator end() const {

    return super_type::end();

  }

  const_reverse_iterator rbegin() const {

    return super_type::rbegin();

  }

  const_reverse_iterator rend() const {

    return super_type::rend();

  }

#ifndef BOOST_NO_MEMBER_TEMPLATE_FRIENDS

private:

  template <typename,std::size_t> friend class multi_array_impl_base;

#else

public: // should be private

#endif

  // constructor used by multi_array_impl_base::generate_array_view to

  // generate array views

  template <typename ExtentList, typename Index>

  explicit multi_array_view(T* base,

                            const ExtentList& extents,

                            const boost::array<Index,NumDims>& strides) :

    super_type(base,extents,strides) { }

};

} // namespace multi_array

} // namespace detail

//

// traits classes to get array_view types

//

template <typename Array, int N>

class array_view_gen {

  typedef typename Array::element element;

public:

  typedef boost::detail::multi_array::multi_array_view<element,N> type;

};

template <typename Array, int N>

class const_array_view_gen {

  typedef typename Array::element element;

public:

  typedef boost::detail::multi_array::const_multi_array_view<element,N> type;  

};

} // namespace boost

#endif // BOOST_MULTI_ARRAY_VIEW_RG071301_HPP