base.hpp

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// 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 BASE_RG071801_HPP
#define BASE_RG071801_HPP

//
// base.hpp - some implementation base classes for from which
// functionality is acquired
//

#include "boost/multi_array/extent_range.hpp"
#include "boost/multi_array/extent_gen.hpp"
#include "boost/multi_array/index_range.hpp"
#include "boost/multi_array/index_gen.hpp"
#include "boost/multi_array/storage_order.hpp"
#include "boost/multi_array/types.hpp"
#include "boost/config.hpp"
#include "boost/multi_array/concept_checks.hpp" //for ignore_unused_...
#include "boost/mpl/eval_if.hpp"
#include "boost/mpl/if.hpp"
#include "boost/mpl/size_t.hpp"
#include "boost/mpl/aux_/msvc_eti_base.hpp"
#include "boost/iterator/reverse_iterator.hpp"
#include "boost/static_assert.hpp"
#include "boost/type.hpp"
#include "boost/assert.hpp"
#include <cstddef>
#include <memory>

namespace boost {

/////////////////////////////////////////////////////////////////////////
// class declarations
/////////////////////////////////////////////////////////////////////////

template<typename T, std::size_t NumDims,
  typename Allocator = std::allocator<T> >
class multi_array;

// This is a public interface for use by end users!
namespace multi_array_types {
  typedef boost::detail::multi_array::size_type size_type;
  typedef std::ptrdiff_t difference_type;
  typedef boost::detail::multi_array::index index;
  typedef detail::multi_array::index_range<index,size_type> index_range;
  typedef detail::multi_array::extent_range<index,size_type> extent_range;
  typedef detail::multi_array::index_gen<0,0> index_gen;
  typedef detail::multi_array::extent_gen<0> extent_gen;
}


// boost::extents and boost::indices are now a part of the public
// interface.  That way users don't necessarily have to create their 
// own objects.  On the other hand, one may not want the overhead of 
// object creation in small-memory environments.  Thus, the objects
// can be left undefined by defining BOOST_MULTI_ARRAY_NO_GENERATORS 
// before loading multi_array.hpp.
#if !BOOST_MULTI_ARRAY_NO_GENERATORS
namespace {
  multi_array_types::extent_gen extents;
  multi_array_types::index_gen indices;
}
#endif // BOOST_MULTI_ARRAY_NO_GENERATORS

namespace detail {
namespace multi_array {

template <typename T, std::size_t NumDims>
class sub_array;

template <typename T, std::size_t NumDims, typename TPtr = const T*>
class const_sub_array;

template <typename T, typename TPtr, typename NumDims, typename Reference>
class array_iterator;

template <typename T, std::size_t NumDims, typename TPtr = const T*>
class const_multi_array_view;

template <typename T, std::size_t NumDims>
class multi_array_view;

/////////////////////////////////////////////////////////////////////////
// class interfaces
/////////////////////////////////////////////////////////////////////////

class multi_array_base {
public:
  typedef multi_array_types::size_type size_type;
  typedef multi_array_types::difference_type difference_type;
  typedef multi_array_types::index index;
  typedef multi_array_types::index_range index_range;
  typedef multi_array_types::extent_range extent_range;
  typedef multi_array_types::index_gen index_gen;
  typedef multi_array_types::extent_gen extent_gen;
};

//
// value_accessor_n
//  contains the routines for accessing elements from
//  N-dimensional views.
//
template<typename T, std::size_t NumDims>
class value_accessor_n : public multi_array_base {
  typedef multi_array_base super_type;
public:
  typedef typename super_type::index index;

  // 
  // public typedefs used by classes that inherit from this base
  //
  typedef T element;
  typedef boost::multi_array<T,NumDims-1> value_type;
  typedef sub_array<T,NumDims-1> reference;
  typedef const_sub_array<T,NumDims-1> const_reference;

protected:
  // used by array operator[] and iterators to get reference types.
  template <typename Reference, typename TPtr>
  Reference access(boost::type<Reference>,index idx,TPtr base,
                   const size_type* extents,
                   const index* strides,
                   const index* index_bases) const {

    BOOST_ASSERT(idx - index_bases[0] >= 0);
    BOOST_ASSERT(size_type(idx - index_bases[0]) < extents[0]);
    // return a sub_array<T,NDims-1> proxy object
    TPtr newbase = base + idx * strides[0];
    return Reference(newbase,extents+1,strides+1,index_bases+1);

  }

  value_accessor_n() { }
  ~value_accessor_n() { }
};



//
// value_accessor_one
//  contains the routines for accessing reference elements from
//  1-dimensional views.
//
template<typename T>
class value_accessor_one : public multi_array_base {
  typedef multi_array_base super_type;
public:
  typedef typename super_type::index index;
  //
  // public typedefs for use by classes that inherit it.
  //
  typedef T element;
  typedef T value_type;
  typedef T& reference;
  typedef T const& const_reference;

protected:
  // used by array operator[] and iterators to get reference types.
  template <typename Reference, typename TPtr>
  Reference access(boost::type<Reference>,index idx,TPtr base,
                   const size_type* extents,
                   const index* strides,
                   const index* index_bases) const {

    ignore_unused_variable_warning(index_bases);
    ignore_unused_variable_warning(extents);
    BOOST_ASSERT(idx - index_bases[0] >= 0);
    BOOST_ASSERT(size_type(idx - index_bases[0]) < extents[0]);
    return *(base + idx * strides[0]);
  }

  value_accessor_one() { }
  ~value_accessor_one() { }
};


/////////////////////////////////////////////////////////////////////////
// choose value accessor begins
//

template <typename T, std::size_t NumDims>
struct choose_value_accessor_n {
  typedef value_accessor_n<T,NumDims> type;
};

template <typename T>
struct choose_value_accessor_one {
  typedef value_accessor_one<T> type;
};

template <typename T, typename NumDims>
struct value_accessor_generator {
    BOOST_STATIC_CONSTANT(std::size_t, dimensionality = NumDims::value);
    
  typedef typename
  mpl::eval_if_c<(dimensionality == 1),
                  choose_value_accessor_one<T>,
                  choose_value_accessor_n<T,dimensionality>
  >::type type;
};

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)

struct eti_value_accessor
{
  typedef int index;
  typedef int size_type;
  typedef int element;
  typedef int index_range;
  typedef int value_type;
  typedef int reference;
  typedef int const_reference;
};
    
template <>
struct value_accessor_generator<int,int>
{
  typedef eti_value_accessor type;
};

template <class T, class NumDims>
struct associated_types
  : mpl::aux::msvc_eti_base<
        typename value_accessor_generator<T,NumDims>::type
    >::type
{};

template <>
struct associated_types<int,int> : eti_value_accessor {};