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Rocket.Chat.ReactNative/ios/Pods/boost-for-react-native/boost/multi_array/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/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.
#ifndef 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,
typename IteratorCategory>
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;
};
template <class T, class NumDims>
struct associated_types
: value_accessor_generator<T,NumDims>::type
{};
//
// choose value accessor ends
/////////////////////////////////////////////////////////////////////////
// Due to some imprecision in the C++ Standard,
// MSVC 2010 is broken in debug mode: it requires
// that an Output Iterator have output_iterator_tag in its iterator_category if
// that iterator is not bidirectional_iterator or random_access_iterator.
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1600)
struct mutable_iterator_tag
: boost::random_access_traversal_tag, std::input_iterator_tag
{
operator std::output_iterator_tag() const {
return std::output_iterator_tag();
}
};
#endif
////////////////////////////////////////////////////////////////////////
// multi_array_base
////////////////////////////////////////////////////////////////////////
template <typename T, std::size_t NumDims>
class multi_array_impl_base
:
public value_accessor_generator<T,mpl::size_t<NumDims> >::type
{
typedef associated_types<T,mpl::size_t<NumDims> > types;
public:
typedef typename types::index index;
typedef typename types::size_type size_type;
typedef typename types::element element;
typedef typename types::index_range index_range;
typedef typename types::value_type value_type;
typedef typename types::reference reference;
typedef typename types::const_reference const_reference;
template <std::size_t NDims>
struct subarray {
typedef boost::detail::multi_array::sub_array<T,NDims> type;
};
template <std::size_t NDims>
struct const_subarray {
typedef boost::detail::multi_array::const_sub_array<T,NDims> type;
};
template <std::size_t NDims>
struct array_view {
typedef boost::detail::multi_array::multi_array_view<T,NDims> type;
};
template <std::size_t NDims>
struct const_array_view {
public:
typedef boost::detail::multi_array::const_multi_array_view<T,NDims> type;
};
//
// iterator support
//
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1600)
// Deal with VC 2010 output_iterator_tag requirement
typedef array_iterator<T,T*,mpl::size_t<NumDims>,reference,
mutable_iterator_tag> iterator;
#else
typedef array_iterator<T,T*,mpl::size_t<NumDims>,reference,
boost::random_access_traversal_tag> iterator;
#endif
typedef array_iterator<T,T const*,mpl::size_t<NumDims>,const_reference,
boost::random_access_traversal_tag> const_iterator;
typedef ::boost::reverse_iterator<iterator> reverse_iterator;
typedef ::boost::reverse_iterator<const_iterator> const_reverse_iterator;
BOOST_STATIC_CONSTANT(std::size_t, dimensionality = NumDims);
protected:
multi_array_impl_base() { }
~multi_array_impl_base() { }
// Used by operator() in our array classes
template <typename Reference, typename IndexList, typename TPtr>
Reference access_element(boost::type<Reference>,
const IndexList& indices,
TPtr base,
const size_type* extents,
const index* strides,
const index* index_bases) const {
boost::function_requires<
CollectionConcept<IndexList> >();
ignore_unused_variable_warning(index_bases);
ignore_unused_variable_warning(extents);
#if !defined(NDEBUG) && !defined(BOOST_DISABLE_ASSERTS)
for (size_type i = 0; i != NumDims; ++i) {
BOOST_ASSERT(indices[i] - index_bases[i] >= 0);
BOOST_ASSERT(size_type(indices[i] - index_bases[i]) < extents[i]);
}
#endif
index offset = 0;
{
typename IndexList::const_iterator i = indices.begin();
size_type n = 0;
while (n != NumDims) {
offset += (*i) * strides[n];
++n;
++i;
}
}
return base[offset];
}
template <typename StrideList, typename ExtentList>
void compute_strides(StrideList& stride_list, ExtentList& extent_list,
const general_storage_order<NumDims>& storage)
{
// invariant: stride = the stride for dimension n
index stride = 1;
for (size_type n = 0; n != NumDims; ++n) {
index stride_sign = +1;
if (!storage.ascending(storage.ordering(n)))
stride_sign = -1;
// The stride for this dimension is the product of the
// lengths of the ranks minor to it.
stride_list[storage.ordering(n)] = stride * stride_sign;
stride *= extent_list[storage.ordering(n)];
}
}
// This calculates the offset to the array base pointer due to:
// 1. dimensions stored in descending order
// 2. non-zero dimension index bases
template <typename StrideList, typename ExtentList, typename BaseList>
index
calculate_origin_offset(const StrideList& stride_list,
const ExtentList& extent_list,
const general_storage_order<NumDims>& storage,
const BaseList& index_base_list)
{
return
calculate_descending_dimension_offset(stride_list,extent_list,
storage) +
calculate_indexing_offset(stride_list,index_base_list);
}
// This calculates the offset added to the base pointer that are
// caused by descending dimensions
template <typename StrideList, typename ExtentList>
index
calculate_descending_dimension_offset(const StrideList& stride_list,
const ExtentList& extent_list,
const general_storage_order<NumDims>& storage)
{
index offset = 0;
if (!storage.all_dims_ascending())
for (size_type n = 0; n != NumDims; ++n)
if (!storage.ascending(n))
offset -= (extent_list[n] - 1) * stride_list[n];
return offset;
}
// This is used to reindex array_views, which are no longer
// concerned about storage order (specifically, whether dimensions
// are ascending or descending) since the viewed array handled it.
template <typename StrideList, typename BaseList>
index
calculate_indexing_offset(const StrideList& stride_list,
const BaseList& index_base_list)
{
index offset = 0;
for (size_type n = 0; n != NumDims; ++n)
offset -= stride_list[n] * index_base_list[n];
return offset;
}
// Slicing using an index_gen.
// Note that populating an index_gen creates a type that encodes
// both the number of dimensions in the current Array (NumDims), and
// the Number of dimensions for the resulting view. This allows the
// compiler to fail if the dimensions aren't completely accounted
// for. For reasons unbeknownst to me, a BOOST_STATIC_ASSERT
// within the member function template does not work. I should add a
// note to the documentation specifying that you get a damn ugly
// error message if you screw up in your slicing code.
template <typename ArrayRef, int NDims, typename TPtr>
ArrayRef
generate_array_view(boost::type<ArrayRef>,
const boost::detail::multi_array::
index_gen<NumDims,NDims>& indices,
const size_type* extents,
const index* strides,
const index* index_bases,
TPtr base) const {
boost::array<index,NDims> new_strides;
boost::array<index,NDims> new_extents;
index offset = 0;
size_type dim = 0;
for (size_type n = 0; n != NumDims; ++n) {
// Use array specs and input specs to produce real specs.
const index default_start = index_bases[n];
const index default_finish = default_start+extents[n];
const index_range& current_range = indices.ranges_[n];
index start = current_range.get_start(default_start);
index finish = current_range.get_finish(default_finish);
index stride = current_range.stride();
BOOST_ASSERT(stride != 0);
// An index range indicates a half-open strided interval
// [start,finish) (with stride) which faces upward when stride
// is positive and downward when stride is negative,
// RG: The following code for calculating length suffers from
// some representation issues: if finish-start cannot be represented as
// by type index, then overflow may result.
index len;
if ((finish - start) / stride < 0) {
// [start,finish) is empty according to the direction imposed by
// the stride.
len = 0;
} else {
// integral trick for ceiling((finish-start) / stride)
// taking into account signs.
index shrinkage = stride > 0 ? 1 : -1;
len = (finish - start + (stride - shrinkage)) / stride;
}
// start marks the closed side of the range, so it must lie
// exactly in the set of legal indices
// with a special case for empty arrays
BOOST_ASSERT(index_bases[n] <= start &&
((start <= index_bases[n]+index(extents[n])) ||
(start == index_bases[n] && extents[n] == 0)));
#ifndef BOOST_DISABLE_ASSERTS
// finish marks the open side of the range, so it can go one past
// the "far side" of the range (the top if stride is positive, the bottom
// if stride is negative).
index bound_adjustment = stride < 0 ? 1 : 0;
BOOST_ASSERT(((index_bases[n] - bound_adjustment) <= finish) &&
(finish <= (index_bases[n] + index(extents[n]) - bound_adjustment)));
#endif // BOOST_DISABLE_ASSERTS
// the array data pointer is modified to account for non-zero
// bases during slicing (see [Garcia] for the math involved)
offset += start * strides[n];
if (!current_range.is_degenerate()) {
// The stride for each dimension is included into the
// strides for the array_view (see [Garcia] for the math involved).
new_strides[dim] = stride * strides[n];
// calculate new extents
new_extents[dim] = len;
++dim;
}
}
BOOST_ASSERT(dim == NDims);
return
ArrayRef(base+offset,
new_extents,
new_strides);
}
};
} // namespace multi_array
} // namespace detail
} // namespace boost
#endif // BASE_RG071801_HPP
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