Chris@16: // Copyright 2002 The Trustees of Indiana University.
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software 
Chris@16: // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  Boost.MultiArray Library
Chris@16: //  Authors: Ronald Garcia
Chris@16: //           Jeremy Siek
Chris@16: //           Andrew Lumsdaine
Chris@16: //  See http://www.boost.org/libs/multi_array for documentation.
Chris@16: 
Chris@16: #ifndef BASE_RG071801_HPP
Chris@16: #define BASE_RG071801_HPP
Chris@16: 
Chris@16: //
Chris@16: // base.hpp - some implementation base classes for from which
Chris@16: // functionality is acquired
Chris@16: //
Chris@16: 
Chris@16: #include "boost/multi_array/extent_range.hpp"
Chris@16: #include "boost/multi_array/extent_gen.hpp"
Chris@16: #include "boost/multi_array/index_range.hpp"
Chris@16: #include "boost/multi_array/index_gen.hpp"
Chris@16: #include "boost/multi_array/storage_order.hpp"
Chris@16: #include "boost/multi_array/types.hpp"
Chris@16: #include "boost/config.hpp"
Chris@16: #include "boost/multi_array/concept_checks.hpp" //for ignore_unused_...
Chris@16: #include "boost/mpl/eval_if.hpp"
Chris@16: #include "boost/mpl/if.hpp"
Chris@16: #include "boost/mpl/size_t.hpp"
Chris@16: #include "boost/iterator/reverse_iterator.hpp"
Chris@16: #include "boost/static_assert.hpp"
Chris@16: #include "boost/type.hpp"
Chris@16: #include "boost/assert.hpp"
Chris@16: #include <cstddef>
Chris@16: #include <memory>
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: /////////////////////////////////////////////////////////////////////////
Chris@16: // class declarations
Chris@16: /////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: template<typename T, std::size_t NumDims,
Chris@16:   typename Allocator = std::allocator<T> >
Chris@16: class multi_array;
Chris@16: 
Chris@16: // This is a public interface for use by end users!
Chris@16: namespace multi_array_types {
Chris@16:   typedef boost::detail::multi_array::size_type size_type;
Chris@16:   typedef std::ptrdiff_t difference_type;
Chris@16:   typedef boost::detail::multi_array::index index;
Chris@16:   typedef detail::multi_array::index_range<index,size_type> index_range;
Chris@16:   typedef detail::multi_array::extent_range<index,size_type> extent_range;
Chris@16:   typedef detail::multi_array::index_gen<0,0> index_gen;
Chris@16:   typedef detail::multi_array::extent_gen<0> extent_gen;
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: // boost::extents and boost::indices are now a part of the public
Chris@16: // interface.  That way users don't necessarily have to create their 
Chris@16: // own objects.  On the other hand, one may not want the overhead of 
Chris@16: // object creation in small-memory environments.  Thus, the objects
Chris@16: // can be left undefined by defining BOOST_MULTI_ARRAY_NO_GENERATORS 
Chris@16: // before loading multi_array.hpp.
Chris@101: #ifndef BOOST_MULTI_ARRAY_NO_GENERATORS
Chris@16: namespace {
Chris@16:   multi_array_types::extent_gen extents;
Chris@16:   multi_array_types::index_gen indices;
Chris@16: }
Chris@16: #endif // BOOST_MULTI_ARRAY_NO_GENERATORS
Chris@16: 
Chris@16: namespace detail {
Chris@16: namespace multi_array {
Chris@16: 
Chris@16: template <typename T, std::size_t NumDims>
Chris@16: class sub_array;
Chris@16: 
Chris@16: template <typename T, std::size_t NumDims, typename TPtr = const T*>
Chris@16: class const_sub_array;
Chris@16: 
Chris@16:   template <typename T, typename TPtr, typename NumDims, typename Reference,
Chris@16:             typename IteratorCategory>
Chris@16: class array_iterator;
Chris@16: 
Chris@16: template <typename T, std::size_t NumDims, typename TPtr = const T*>
Chris@16: class const_multi_array_view;
Chris@16: 
Chris@16: template <typename T, std::size_t NumDims>
Chris@16: class multi_array_view;
Chris@16: 
Chris@16: /////////////////////////////////////////////////////////////////////////
Chris@16: // class interfaces
Chris@16: /////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: class multi_array_base {
Chris@16: public:
Chris@16:   typedef multi_array_types::size_type size_type;
Chris@16:   typedef multi_array_types::difference_type difference_type;
Chris@16:   typedef multi_array_types::index index;
Chris@16:   typedef multi_array_types::index_range index_range;
Chris@16:   typedef multi_array_types::extent_range extent_range;
Chris@16:   typedef multi_array_types::index_gen index_gen;
Chris@16:   typedef multi_array_types::extent_gen extent_gen;
Chris@16: };
Chris@16: 
Chris@16: //
Chris@16: // value_accessor_n
Chris@16: //  contains the routines for accessing elements from
Chris@16: //  N-dimensional views.
Chris@16: //
Chris@16: template<typename T, std::size_t NumDims>
Chris@16: class value_accessor_n : public multi_array_base {
Chris@16:   typedef multi_array_base super_type;
Chris@16: public:
Chris@16:   typedef typename super_type::index index;
Chris@16: 
Chris@16:   // 
Chris@16:   // public typedefs used by classes that inherit from this base
Chris@16:   //
Chris@16:   typedef T element;
Chris@16:   typedef boost::multi_array<T,NumDims-1> value_type;
Chris@16:   typedef sub_array<T,NumDims-1> reference;
Chris@16:   typedef const_sub_array<T,NumDims-1> const_reference;
Chris@16: 
Chris@16: protected:
Chris@16:   // used by array operator[] and iterators to get reference types.
Chris@16:   template <typename Reference, typename TPtr>
Chris@16:   Reference access(boost::type<Reference>,index idx,TPtr base,
Chris@16:                    const size_type* extents,
Chris@16:                    const index* strides,
Chris@16:                    const index* index_bases) const {
Chris@16: 
Chris@16:     BOOST_ASSERT(idx - index_bases[0] >= 0);
Chris@16:     BOOST_ASSERT(size_type(idx - index_bases[0]) < extents[0]);
Chris@16:     // return a sub_array<T,NDims-1> proxy object
Chris@16:     TPtr newbase = base + idx * strides[0];
Chris@16:     return Reference(newbase,extents+1,strides+1,index_bases+1);
Chris@16: 
Chris@16:   }
Chris@16: 
Chris@16:   value_accessor_n() { }
Chris@16:   ~value_accessor_n() { }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: //
Chris@16: // value_accessor_one
Chris@16: //  contains the routines for accessing reference elements from
Chris@16: //  1-dimensional views.
Chris@16: //
Chris@16: template<typename T>
Chris@16: class value_accessor_one : public multi_array_base {
Chris@16:   typedef multi_array_base super_type;
Chris@16: public:
Chris@16:   typedef typename super_type::index index;
Chris@16:   //
Chris@16:   // public typedefs for use by classes that inherit it.
Chris@16:   //
Chris@16:   typedef T element;
Chris@16:   typedef T value_type;
Chris@16:   typedef T& reference;
Chris@16:   typedef T const& const_reference;
Chris@16: 
Chris@16: protected:
Chris@16:   // used by array operator[] and iterators to get reference types.
Chris@16:   template <typename Reference, typename TPtr>
Chris@16:   Reference access(boost::type<Reference>,index idx,TPtr base,
Chris@16:                    const size_type* extents,
Chris@16:                    const index* strides,
Chris@16:                    const index* index_bases) const {
Chris@16: 
Chris@16:     ignore_unused_variable_warning(index_bases);
Chris@16:     ignore_unused_variable_warning(extents);
Chris@16:     BOOST_ASSERT(idx - index_bases[0] >= 0);
Chris@16:     BOOST_ASSERT(size_type(idx - index_bases[0]) < extents[0]);
Chris@16:     return *(base + idx * strides[0]);
Chris@16:   }
Chris@16: 
Chris@16:   value_accessor_one() { }
Chris@16:   ~value_accessor_one() { }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: /////////////////////////////////////////////////////////////////////////
Chris@16: // choose value accessor begins
Chris@16: //
Chris@16: 
Chris@16: template <typename T, std::size_t NumDims>
Chris@16: struct choose_value_accessor_n {
Chris@16:   typedef value_accessor_n<T,NumDims> type;
Chris@16: };
Chris@16: 
Chris@16: template <typename T>
Chris@16: struct choose_value_accessor_one {
Chris@16:   typedef value_accessor_one<T> type;
Chris@16: };
Chris@16: 
Chris@16: template <typename T, typename NumDims>
Chris@16: struct value_accessor_generator {
Chris@16:     BOOST_STATIC_CONSTANT(std::size_t, dimensionality = NumDims::value);
Chris@16:     
Chris@16:   typedef typename
Chris@16:   mpl::eval_if_c<(dimensionality == 1),
Chris@16:                   choose_value_accessor_one<T>,
Chris@16:                   choose_value_accessor_n<T,dimensionality>
Chris@16:   >::type type;
Chris@16: };
Chris@16: 
Chris@16: template <class T, class NumDims>
Chris@16: struct associated_types
Chris@16:   : value_accessor_generator<T,NumDims>::type
Chris@16: {};
Chris@16: 
Chris@16: //
Chris@16: // choose value accessor ends
Chris@16: /////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: // Due to some imprecision in the C++ Standard, 
Chris@16: // MSVC 2010 is broken in debug mode: it requires
Chris@16: // that an Output Iterator have output_iterator_tag in its iterator_category if 
Chris@16: // that iterator is not bidirectional_iterator or random_access_iterator.
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, >= 1600)
Chris@16: struct mutable_iterator_tag
Chris@16:  : boost::random_access_traversal_tag, std::input_iterator_tag
Chris@16: {
Chris@16:   operator std::output_iterator_tag() const {
Chris@16:     return std::output_iterator_tag();
Chris@16:   }
Chris@16: };
Chris@16: #endif
Chris@16: 
Chris@16: ////////////////////////////////////////////////////////////////////////
Chris@16: // multi_array_base
Chris@16: ////////////////////////////////////////////////////////////////////////
Chris@16: template <typename T, std::size_t NumDims>
Chris@16: class multi_array_impl_base
Chris@16:   :
Chris@16:       public value_accessor_generator<T,mpl::size_t<NumDims> >::type
Chris@16: {
Chris@16:   typedef associated_types<T,mpl::size_t<NumDims> > types;
Chris@16: public:
Chris@16:   typedef typename types::index index;
Chris@16:   typedef typename types::size_type size_type;
Chris@16:   typedef typename types::element element;
Chris@16:   typedef typename types::index_range index_range;
Chris@16:   typedef typename types::value_type value_type;
Chris@16:   typedef typename types::reference reference;
Chris@16:   typedef typename types::const_reference const_reference;
Chris@16: 
Chris@16:   template <std::size_t NDims>
Chris@16:   struct subarray {
Chris@16:     typedef boost::detail::multi_array::sub_array<T,NDims> type;
Chris@16:   };
Chris@16: 
Chris@16:   template <std::size_t NDims>
Chris@16:   struct const_subarray {
Chris@16:     typedef boost::detail::multi_array::const_sub_array<T,NDims> type;
Chris@16:   };
Chris@16: 
Chris@16:   template <std::size_t NDims>
Chris@16:   struct array_view {
Chris@16:     typedef boost::detail::multi_array::multi_array_view<T,NDims> type;
Chris@16:   };
Chris@16: 
Chris@16:   template <std::size_t NDims>
Chris@16:   struct const_array_view {
Chris@16:   public:
Chris@16:     typedef boost::detail::multi_array::const_multi_array_view<T,NDims> type;
Chris@16:   };
Chris@16: 
Chris@16:   //
Chris@16:   // iterator support
Chris@16:   //
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, >= 1600)
Chris@16:   // Deal with VC 2010 output_iterator_tag requirement
Chris@16:   typedef array_iterator<T,T*,mpl::size_t<NumDims>,reference,
Chris@16:                          mutable_iterator_tag> iterator;
Chris@16: #else
Chris@16:   typedef array_iterator<T,T*,mpl::size_t<NumDims>,reference,
Chris@16:                          boost::random_access_traversal_tag> iterator;
Chris@16: #endif
Chris@16:   typedef array_iterator<T,T const*,mpl::size_t<NumDims>,const_reference,
Chris@16:                          boost::random_access_traversal_tag> const_iterator;
Chris@16: 
Chris@16:   typedef ::boost::reverse_iterator<iterator> reverse_iterator;
Chris@16:   typedef ::boost::reverse_iterator<const_iterator> const_reverse_iterator;
Chris@16: 
Chris@16:   BOOST_STATIC_CONSTANT(std::size_t, dimensionality = NumDims);
Chris@16: protected:
Chris@16: 
Chris@16:   multi_array_impl_base() { }
Chris@16:   ~multi_array_impl_base() { }
Chris@16: 
Chris@16:   // Used by operator() in our array classes
Chris@16:   template <typename Reference, typename IndexList, typename TPtr>
Chris@16:   Reference access_element(boost::type<Reference>,
Chris@16:                            const IndexList& indices,
Chris@16:                            TPtr base,
Chris@16:                            const size_type* extents,
Chris@16:                            const index* strides,
Chris@16:                            const index* index_bases) const {
Chris@16:     boost::function_requires<
Chris@16:       CollectionConcept<IndexList> >();
Chris@16:     ignore_unused_variable_warning(index_bases);
Chris@16:     ignore_unused_variable_warning(extents);
Chris@16: #if !defined(NDEBUG) && !defined(BOOST_DISABLE_ASSERTS)
Chris@16:     for (size_type i = 0; i != NumDims; ++i) {
Chris@16:       BOOST_ASSERT(indices[i] - index_bases[i] >= 0);
Chris@16:       BOOST_ASSERT(size_type(indices[i] - index_bases[i]) < extents[i]);
Chris@16:     }
Chris@16: #endif
Chris@16: 
Chris@16:     index offset = 0;
Chris@16:     {
Chris@16:       typename IndexList::const_iterator i = indices.begin();
Chris@16:       size_type n = 0; 
Chris@16:       while (n != NumDims) {
Chris@16:         offset += (*i) * strides[n];
Chris@16:         ++n;
Chris@16:         ++i;
Chris@16:       }
Chris@16:     }
Chris@16:     return base[offset];
Chris@16:   }
Chris@16: 
Chris@16:   template <typename StrideList, typename ExtentList>
Chris@16:   void compute_strides(StrideList& stride_list, ExtentList& extent_list,
Chris@16:                        const general_storage_order<NumDims>& storage)
Chris@16:   {
Chris@16:     // invariant: stride = the stride for dimension n
Chris@16:     index stride = 1;
Chris@16:     for (size_type n = 0; n != NumDims; ++n) {
Chris@16:       index stride_sign = +1;
Chris@16:       
Chris@16:       if (!storage.ascending(storage.ordering(n)))
Chris@16:         stride_sign = -1;
Chris@16:       
Chris@16:       // The stride for this dimension is the product of the
Chris@16:       // lengths of the ranks minor to it.
Chris@16:       stride_list[storage.ordering(n)] = stride * stride_sign;
Chris@16:       
Chris@16:       stride *= extent_list[storage.ordering(n)];
Chris@16:     } 
Chris@16:   }
Chris@16: 
Chris@16:   // This calculates the offset to the array base pointer due to:
Chris@16:   // 1. dimensions stored in descending order
Chris@16:   // 2. non-zero dimension index bases
Chris@16:   template <typename StrideList, typename ExtentList, typename BaseList>
Chris@16:   index
Chris@16:   calculate_origin_offset(const StrideList& stride_list,
Chris@16:                           const ExtentList& extent_list,
Chris@16:                           const general_storage_order<NumDims>& storage,
Chris@16:                           const BaseList& index_base_list)
Chris@16:   {
Chris@16:     return
Chris@16:       calculate_descending_dimension_offset(stride_list,extent_list,
Chris@16:                                             storage) +
Chris@16:       calculate_indexing_offset(stride_list,index_base_list);
Chris@16:   }
Chris@16: 
Chris@16:   // This calculates the offset added to the base pointer that are
Chris@16:   // caused by descending dimensions
Chris@16:   template <typename StrideList, typename ExtentList>
Chris@16:   index
Chris@16:   calculate_descending_dimension_offset(const StrideList& stride_list,
Chris@16:                                 const ExtentList& extent_list,
Chris@16:                                 const general_storage_order<NumDims>& storage)
Chris@16:   {
Chris@16:     index offset = 0;
Chris@16:     if (!storage.all_dims_ascending()) 
Chris@16:       for (size_type n = 0; n != NumDims; ++n)
Chris@16:         if (!storage.ascending(n))
Chris@16:           offset -= (extent_list[n] - 1) * stride_list[n];
Chris@16: 
Chris@16:     return offset;
Chris@16:   }
Chris@16: 
Chris@16:   // This is used to reindex array_views, which are no longer
Chris@16:   // concerned about storage order (specifically, whether dimensions
Chris@16:   // are ascending or descending) since the viewed array handled it.
Chris@16: 
Chris@16:   template <typename StrideList, typename BaseList>
Chris@16:   index
Chris@16:   calculate_indexing_offset(const StrideList& stride_list,
Chris@16:                           const BaseList& index_base_list)
Chris@16:   {
Chris@16:     index offset = 0;
Chris@16:     for (size_type n = 0; n != NumDims; ++n)
Chris@16:         offset -= stride_list[n] * index_base_list[n];
Chris@16:     return offset;
Chris@16:   }
Chris@16: 
Chris@16:   // Slicing using an index_gen.
Chris@16:   // Note that populating an index_gen creates a type that encodes
Chris@16:   // both the number of dimensions in the current Array (NumDims), and 
Chris@16:   // the Number of dimensions for the resulting view.  This allows the 
Chris@16:   // compiler to fail if the dimensions aren't completely accounted
Chris@16:   // for.  For reasons unbeknownst to me, a BOOST_STATIC_ASSERT
Chris@16:   // within the member function template does not work. I should add a 
Chris@16:   // note to the documentation specifying that you get a damn ugly
Chris@16:   // error message if you screw up in your slicing code.
Chris@16:   template <typename ArrayRef, int NDims, typename TPtr>
Chris@16:   ArrayRef
Chris@16:   generate_array_view(boost::type<ArrayRef>,
Chris@16:                       const boost::detail::multi_array::
Chris@16:                       index_gen<NumDims,NDims>& indices,
Chris@16:                       const size_type* extents,
Chris@16:                       const index* strides,
Chris@16:                       const index* index_bases,
Chris@16:                       TPtr base) const {
Chris@16: 
Chris@16:     boost::array<index,NDims> new_strides;
Chris@16:     boost::array<index,NDims> new_extents;
Chris@16: 
Chris@16:     index offset = 0;
Chris@16:     size_type dim = 0;
Chris@16:     for (size_type n = 0; n != NumDims; ++n) {
Chris@16: 
Chris@16:       // Use array specs and input specs to produce real specs.
Chris@16:       const index default_start = index_bases[n];
Chris@16:       const index default_finish = default_start+extents[n];
Chris@16:       const index_range& current_range = indices.ranges_[n];
Chris@16:       index start = current_range.get_start(default_start);
Chris@16:       index finish = current_range.get_finish(default_finish);
Chris@16:       index stride = current_range.stride();
Chris@16:       BOOST_ASSERT(stride != 0);
Chris@16: 
Chris@16:       // An index range indicates a half-open strided interval 
Chris@16:       // [start,finish) (with stride) which faces upward when stride 
Chris@16:       // is positive and downward when stride is negative, 
Chris@16: 
Chris@16:       // RG: The following code for calculating length suffers from 
Chris@16:       // some representation issues: if finish-start cannot be represented as
Chris@16:       // by type index, then overflow may result.
Chris@16: 
Chris@16:       index len;
Chris@16:       if ((finish - start) / stride < 0) {
Chris@16:         // [start,finish) is empty according to the direction imposed by 
Chris@16:         // the stride.
Chris@16:         len = 0;
Chris@16:       } else {
Chris@16:         // integral trick for ceiling((finish-start) / stride) 
Chris@16:         // taking into account signs.
Chris@16:         index shrinkage = stride > 0 ? 1 : -1;
Chris@16:         len = (finish - start + (stride - shrinkage)) / stride;
Chris@16:       }
Chris@16: 
Chris@16:       // start marks the closed side of the range, so it must lie
Chris@16:       // exactly in the set of legal indices
Chris@16:       // with a special case for empty arrays
Chris@16:       BOOST_ASSERT(index_bases[n] <= start &&
Chris@16:                    ((start <= index_bases[n]+index(extents[n])) ||
Chris@16:                      (start == index_bases[n] && extents[n] == 0)));
Chris@16: 
Chris@16: #ifndef BOOST_DISABLE_ASSERTS
Chris@16:       // finish marks the open side of the range, so it can go one past
Chris@16:       // the "far side" of the range (the top if stride is positive, the bottom
Chris@16:       // if stride is negative).
Chris@16:       index bound_adjustment = stride < 0 ? 1 : 0;
Chris@16:       BOOST_ASSERT(((index_bases[n] - bound_adjustment) <= finish) &&
Chris@16:         (finish <= (index_bases[n] + index(extents[n]) - bound_adjustment)));
Chris@16: #endif // BOOST_DISABLE_ASSERTS
Chris@16: 
Chris@16: 
Chris@16:       // the array data pointer is modified to account for non-zero
Chris@16:       // bases during slicing (see [Garcia] for the math involved)
Chris@16:       offset += start * strides[n];
Chris@16: 
Chris@16:       if (!current_range.is_degenerate()) {
Chris@16: 
Chris@16:         // The stride for each dimension is included into the
Chris@16:         // strides for the array_view (see [Garcia] for the math involved).
Chris@16:         new_strides[dim] = stride * strides[n];
Chris@16:         
Chris@16:         // calculate new extents
Chris@16:         new_extents[dim] = len;
Chris@16:         ++dim;
Chris@16:       }
Chris@16:     }
Chris@16:     BOOST_ASSERT(dim == NDims);
Chris@16: 
Chris@16:     return
Chris@16:       ArrayRef(base+offset,
Chris@16:                new_extents,
Chris@16:                new_strides);
Chris@16:   }
Chris@16:                      
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: } // namespace multi_array
Chris@16: } // namespace detail
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif // BASE_RG071801_HPP