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