1 | // Copyright 2002 The Trustees of Indiana University.
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2 |
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3 | // Use, modification and distribution is subject to the Boost Software
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4 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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5 | // http://www.boost.org/LICENSE_1_0.txt)
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6 |
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7 | // Boost.MultiArray Library
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8 | // Authors: Ronald Garcia
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9 | // Jeremy Siek
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10 | // Andrew Lumsdaine
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11 | // See http://www.boost.org/libs/multi_array for documentation.
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12 |
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13 | #ifndef BASE_RG071801_HPP
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14 | #define BASE_RG071801_HPP
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15 |
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16 | //
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17 | // base.hpp - some implementation base classes for from which
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18 | // functionality is acquired
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19 | //
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20 |
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21 | #include "boost/multi_array/extent_range.hpp"
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22 | #include "boost/multi_array/extent_gen.hpp"
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23 | #include "boost/multi_array/index_range.hpp"
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24 | #include "boost/multi_array/index_gen.hpp"
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25 | #include "boost/multi_array/storage_order.hpp"
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26 | #include "boost/multi_array/types.hpp"
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27 | #include "boost/config.hpp"
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28 | #include "boost/multi_array/concept_checks.hpp" //for ignore_unused_...
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29 | #include "boost/mpl/eval_if.hpp"
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30 | #include "boost/mpl/if.hpp"
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31 | #include "boost/mpl/size_t.hpp"
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32 | #include "boost/mpl/aux_/msvc_eti_base.hpp"
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33 | #include "boost/iterator/reverse_iterator.hpp"
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34 | #include "boost/static_assert.hpp"
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35 | #include "boost/type.hpp"
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36 | #include "boost/assert.hpp"
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37 | #include <cstddef>
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38 | #include <memory>
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39 |
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40 | namespace boost {
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41 |
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42 | /////////////////////////////////////////////////////////////////////////
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43 | // class declarations
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44 | /////////////////////////////////////////////////////////////////////////
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45 |
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46 | template<typename T, std::size_t NumDims,
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47 | typename Allocator = std::allocator<T> >
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48 | class multi_array;
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49 |
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50 | // This is a public interface for use by end users!
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51 | namespace multi_array_types {
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52 | typedef boost::detail::multi_array::size_type size_type;
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53 | typedef std::ptrdiff_t difference_type;
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54 | typedef boost::detail::multi_array::index index;
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55 | typedef detail::multi_array::index_range<index,size_type> index_range;
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56 | typedef detail::multi_array::extent_range<index,size_type> extent_range;
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57 | typedef detail::multi_array::index_gen<0,0> index_gen;
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58 | typedef detail::multi_array::extent_gen<0> extent_gen;
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59 | }
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60 |
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61 |
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62 | // boost::extents and boost::indices are now a part of the public
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63 | // interface. That way users don't necessarily have to create their
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64 | // own objects. On the other hand, one may not want the overhead of
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65 | // object creation in small-memory environments. Thus, the objects
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66 | // can be left undefined by defining BOOST_MULTI_ARRAY_NO_GENERATORS
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67 | // before loading multi_array.hpp.
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68 | #if !BOOST_MULTI_ARRAY_NO_GENERATORS
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69 | namespace {
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70 | multi_array_types::extent_gen extents;
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71 | multi_array_types::index_gen indices;
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72 | }
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73 | #endif // BOOST_MULTI_ARRAY_NO_GENERATORS
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74 |
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75 | namespace detail {
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76 | namespace multi_array {
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77 |
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78 | template <typename T, std::size_t NumDims>
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79 | class sub_array;
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80 |
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81 | template <typename T, std::size_t NumDims, typename TPtr = const T*>
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82 | class const_sub_array;
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83 |
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84 | template <typename T, typename TPtr, typename NumDims, typename Reference,
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85 | typename IteratorCategory>
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86 | class array_iterator;
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87 |
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88 | template <typename T, std::size_t NumDims, typename TPtr = const T*>
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89 | class const_multi_array_view;
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90 |
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91 | template <typename T, std::size_t NumDims>
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92 | class multi_array_view;
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93 |
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94 | /////////////////////////////////////////////////////////////////////////
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95 | // class interfaces
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96 | /////////////////////////////////////////////////////////////////////////
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97 |
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98 | class multi_array_base {
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99 | public:
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100 | typedef multi_array_types::size_type size_type;
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101 | typedef multi_array_types::difference_type difference_type;
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102 | typedef multi_array_types::index index;
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103 | typedef multi_array_types::index_range index_range;
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104 | typedef multi_array_types::extent_range extent_range;
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105 | typedef multi_array_types::index_gen index_gen;
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106 | typedef multi_array_types::extent_gen extent_gen;
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107 | };
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108 |
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109 | //
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110 | // value_accessor_n
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111 | // contains the routines for accessing elements from
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112 | // N-dimensional views.
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113 | //
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114 | template<typename T, std::size_t NumDims>
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115 | class value_accessor_n : public multi_array_base {
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116 | typedef multi_array_base super_type;
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117 | public:
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118 | typedef typename super_type::index index;
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119 |
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120 | //
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121 | // public typedefs used by classes that inherit from this base
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122 | //
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123 | typedef T element;
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124 | typedef boost::multi_array<T,NumDims-1> value_type;
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125 | typedef sub_array<T,NumDims-1> reference;
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126 | typedef const_sub_array<T,NumDims-1> const_reference;
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127 |
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128 | protected:
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129 | // used by array operator[] and iterators to get reference types.
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130 | template <typename Reference, typename TPtr>
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131 | Reference access(boost::type<Reference>,index idx,TPtr base,
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132 | const size_type* extents,
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133 | const index* strides,
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134 | const index* index_bases) const {
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135 |
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136 | BOOST_ASSERT(idx - index_bases[0] >= 0);
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137 | BOOST_ASSERT(size_type(idx - index_bases[0]) < extents[0]);
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138 | // return a sub_array<T,NDims-1> proxy object
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139 | TPtr newbase = base + idx * strides[0];
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140 | return Reference(newbase,extents+1,strides+1,index_bases+1);
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141 |
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142 | }
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143 |
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144 | value_accessor_n() { }
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145 | ~value_accessor_n() { }
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146 | };
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147 |
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148 |
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149 |
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150 | //
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151 | // value_accessor_one
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152 | // contains the routines for accessing reference elements from
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153 | // 1-dimensional views.
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154 | //
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155 | template<typename T>
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156 | class value_accessor_one : public multi_array_base {
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157 | typedef multi_array_base super_type;
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158 | public:
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159 | typedef typename super_type::index index;
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160 | //
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161 | // public typedefs for use by classes that inherit it.
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162 | //
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163 | typedef T element;
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164 | typedef T value_type;
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165 | typedef T& reference;
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166 | typedef T const& const_reference;
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167 |
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168 | protected:
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169 | // used by array operator[] and iterators to get reference types.
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170 | template <typename Reference, typename TPtr>
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171 | Reference access(boost::type<Reference>,index idx,TPtr base,
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172 | const size_type* extents,
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173 | const index* strides,
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174 | const index* index_bases) const {
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175 |
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176 | ignore_unused_variable_warning(index_bases);
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177 | ignore_unused_variable_warning(extents);
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178 | BOOST_ASSERT(idx - index_bases[0] >= 0);
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179 | BOOST_ASSERT(size_type(idx - index_bases[0]) < extents[0]);
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180 | return *(base + idx * strides[0]);
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181 | }
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182 |
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183 | value_accessor_one() { }
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184 | ~value_accessor_one() { }
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185 | };
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186 |
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187 |
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188 | /////////////////////////////////////////////////////////////////////////
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189 | // choose value accessor begins
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190 | //
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191 |
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192 | template <typename T, std::size_t NumDims>
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193 | struct choose_value_accessor_n {
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194 | typedef value_accessor_n<T,NumDims> type;
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195 | };
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196 |
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197 | template <typename T>
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198 | struct choose_value_accessor_one {
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199 | typedef value_accessor_one<T> type;
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200 | };
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201 |
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202 | template <typename T, typename NumDims>
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203 | struct value_accessor_generator {
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204 | BOOST_STATIC_CONSTANT(std::size_t, dimensionality = NumDims::value);
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205 |
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206 | typedef typename
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207 | mpl::eval_if_c<(dimensionality == 1),
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208 | choose_value_accessor_one<T>,
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209 | choose_value_accessor_n<T,dimensionality>
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210 | >::type type;
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211 | };
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212 |
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213 | #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
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214 |
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215 | struct eti_value_accessor
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216 | {
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217 | typedef int index;
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218 | typedef int size_type;
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219 | typedef int element;
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220 | typedef int index_range;
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221 | typedef int value_type;
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222 | typedef int reference;
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223 | typedef int const_reference;
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224 | };
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225 |
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226 | template <>
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227 | struct value_accessor_generator<int,int>
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228 | {
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229 | typedef eti_value_accessor type;
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230 | };
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231 |
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232 | template <class T, class NumDims>
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233 | struct associated_types
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234 | : mpl::aux::msvc_eti_base<
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235 | typename value_accessor_generator<T,NumDims>::type
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236 | >::type
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237 | {};
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238 |
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239 | template <>
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240 | struct associated_types<int,int> : eti_value_accessor {};
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241 |
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242 | #else
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243 |
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244 | template <class T, class NumDims>
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245 | struct associated_types
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246 | : value_accessor_generator<T,NumDims>::type
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247 | {};
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248 |
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249 | #endif
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250 |
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251 | //
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252 | // choose value accessor ends
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253 | /////////////////////////////////////////////////////////////////////////
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254 |
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255 |
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256 | struct mutable_iterator_tag
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257 | : boost::random_access_traversal_tag, std::input_iterator_tag
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258 | {
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259 | #if BOOST_WORKAROUND(BOOST_MSVC, <= 1700)
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260 | operator std::output_iterator_tag() const
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261 | {
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262 | return std::output_iterator_tag();
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263 | }
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264 | #endif
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265 | };
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266 |
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267 |
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268 | ////////////////////////////////////////////////////////////////////////
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269 | // multi_array_base
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270 | ////////////////////////////////////////////////////////////////////////
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271 | template <typename T, std::size_t NumDims>
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272 | class multi_array_impl_base
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273 | :
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274 | #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
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275 | public mpl::aux::msvc_eti_base<
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276 | typename value_accessor_generator<T,mpl::size_t<NumDims> >::type
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277 | >::type
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278 | #else
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279 | public value_accessor_generator<T,mpl::size_t<NumDims> >::type
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280 | #endif
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281 | {
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282 | typedef associated_types<T,mpl::size_t<NumDims> > types;
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283 | public:
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284 | typedef typename types::index index;
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285 | typedef typename types::size_type size_type;
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286 | typedef typename types::element element;
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287 | typedef typename types::index_range index_range;
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288 | typedef typename types::value_type value_type;
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289 | typedef typename types::reference reference;
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290 | typedef typename types::const_reference const_reference;
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291 |
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292 | template <std::size_t NDims>
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293 | struct subarray {
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294 | typedef boost::detail::multi_array::sub_array<T,NDims> type;
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295 | };
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296 |
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297 | template <std::size_t NDims>
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298 | struct const_subarray {
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299 | typedef boost::detail::multi_array::const_sub_array<T,NDims> type;
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300 | };
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301 |
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302 | template <std::size_t NDims>
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303 | struct array_view {
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304 | typedef boost::detail::multi_array::multi_array_view<T,NDims> type;
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305 | };
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306 |
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307 | template <std::size_t NDims>
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308 | struct const_array_view {
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309 | public:
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310 | typedef boost::detail::multi_array::const_multi_array_view<T,NDims> type;
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311 | };
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312 |
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313 | //
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314 | // iterator support
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315 | //
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316 | typedef array_iterator<T,T*,mpl::size_t<NumDims>,reference,
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317 | mutable_iterator_tag> iterator;
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318 | typedef array_iterator<T,T const*,mpl::size_t<NumDims>,const_reference,
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319 | boost::random_access_traversal_tag> const_iterator;
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320 |
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321 | typedef ::boost::reverse_iterator<iterator> reverse_iterator;
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322 | typedef ::boost::reverse_iterator<const_iterator> const_reverse_iterator;
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323 |
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324 | BOOST_STATIC_CONSTANT(std::size_t, dimensionality = NumDims);
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325 | protected:
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326 |
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327 | multi_array_impl_base() { }
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328 | ~multi_array_impl_base() { }
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329 |
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330 | // Used by operator() in our array classes
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331 | template <typename Reference, typename IndexList, typename TPtr>
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332 | Reference access_element(boost::type<Reference>,
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333 | const IndexList& indices,
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334 | TPtr base,
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335 | const size_type* extents,
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336 | const index* strides,
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337 | const index* index_bases) const {
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338 | boost::function_requires<
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339 | CollectionConcept<IndexList> >();
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340 | ignore_unused_variable_warning(index_bases);
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341 | ignore_unused_variable_warning(extents);
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342 | #if !defined(NDEBUG) && !defined(BOOST_DISABLE_ASSERTS)
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343 | for (size_type i = 0; i != NumDims; ++i) {
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344 | BOOST_ASSERT(indices[i] - index_bases[i] >= 0);
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345 | BOOST_ASSERT(size_type(indices[i] - index_bases[i]) < extents[i]);
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346 | }
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347 | #endif
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348 |
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349 | index offset = 0;
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350 | {
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351 | typename IndexList::const_iterator i = indices.begin();
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352 | size_type n = 0;
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353 | while (n != NumDims) {
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354 | offset += (*i) * strides[n];
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355 | ++n;
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356 | ++i;
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357 | }
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358 | }
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359 | return base[offset];
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360 | }
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361 |
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362 | template <typename StrideList, typename ExtentList>
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363 | void compute_strides(StrideList& stride_list, ExtentList& extent_list,
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364 | const general_storage_order<NumDims>& storage)
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365 | {
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366 | // invariant: stride = the stride for dimension n
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367 | index stride = 1;
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368 | for (size_type n = 0; n != NumDims; ++n) {
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369 | index stride_sign = +1;
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370 |
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371 | if (!storage.ascending(storage.ordering(n)))
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372 | stride_sign = -1;
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373 |
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374 | // The stride for this dimension is the product of the
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375 | // lengths of the ranks minor to it.
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376 | stride_list[storage.ordering(n)] = stride * stride_sign;
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377 |
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378 | stride *= extent_list[storage.ordering(n)];
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379 | }
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380 | }
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381 |
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382 | // This calculates the offset to the array base pointer due to:
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383 | // 1. dimensions stored in descending order
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384 | // 2. non-zero dimension index bases
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385 | template <typename StrideList, typename ExtentList, typename BaseList>
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386 | index
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387 | calculate_origin_offset(const StrideList& stride_list,
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388 | const ExtentList& extent_list,
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389 | const general_storage_order<NumDims>& storage,
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390 | const BaseList& index_base_list)
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391 | {
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392 | return
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393 | calculate_descending_dimension_offset(stride_list,extent_list,
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394 | storage) +
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395 | calculate_indexing_offset(stride_list,index_base_list);
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396 | }
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397 |
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398 | // This calculates the offset added to the base pointer that are
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399 | // caused by descending dimensions
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400 | template <typename StrideList, typename ExtentList>
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401 | index
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402 | calculate_descending_dimension_offset(const StrideList& stride_list,
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403 | const ExtentList& extent_list,
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404 | const general_storage_order<NumDims>& storage)
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405 | {
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406 | index offset = 0;
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407 | if (!storage.all_dims_ascending())
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408 | for (size_type n = 0; n != NumDims; ++n)
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409 | if (!storage.ascending(n))
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410 | offset -= (extent_list[n] - 1) * stride_list[n];
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411 |
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412 | return offset;
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413 | }
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414 |
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415 | // This is used to reindex array_views, which are no longer
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416 | // concerned about storage order (specifically, whether dimensions
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417 | // are ascending or descending) since the viewed array handled it.
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418 |
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419 | template <typename StrideList, typename BaseList>
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420 | index
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421 | calculate_indexing_offset(const StrideList& stride_list,
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422 | const BaseList& index_base_list)
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423 | {
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424 | index offset = 0;
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425 | for (size_type n = 0; n != NumDims; ++n)
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426 | offset -= stride_list[n] * index_base_list[n];
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427 | return offset;
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428 | }
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429 |
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430 | // Slicing using an index_gen.
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431 | // Note that populating an index_gen creates a type that encodes
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432 | // both the number of dimensions in the current Array (NumDims), and
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433 | // the Number of dimensions for the resulting view. This allows the
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434 | // compiler to fail if the dimensions aren't completely accounted
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435 | // for. For reasons unbeknownst to me, a BOOST_STATIC_ASSERT
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436 | // within the member function template does not work. I should add a
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437 | // note to the documentation specifying that you get a damn ugly
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438 | // error message if you screw up in your slicing code.
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439 | template <typename ArrayRef, int NDims, typename TPtr>
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440 | ArrayRef
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441 | generate_array_view(boost::type<ArrayRef>,
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442 | const boost::detail::multi_array::
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443 | index_gen<NumDims,NDims>& indices,
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444 | const size_type* extents,
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445 | const index* strides,
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446 | const index* index_bases,
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447 | TPtr base) const {
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448 |
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449 | boost::array<index,NDims> new_strides;
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450 | boost::array<index,NDims> new_extents;
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451 |
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452 | index offset = 0;
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453 | size_type dim = 0;
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454 | for (size_type n = 0; n != NumDims; ++n) {
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455 |
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456 | // Use array specs and input specs to produce real specs.
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457 | const index default_start = index_bases[n];
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458 | const index default_finish = default_start+extents[n];
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459 | const index_range& current_range = indices.ranges_[n];
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460 | index start = current_range.get_start(default_start);
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461 | index finish = current_range.get_finish(default_finish);
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462 | index stride = current_range.stride();
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463 | BOOST_ASSERT(stride != 0);
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464 |
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465 | // An index range indicates a half-open strided interval
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466 | // [start,finish) (with stride) which faces upward when stride
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467 | // is positive and downward when stride is negative,
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468 |
|
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469 | // RG: The following code for calculating length suffers from
|
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470 | // some representation issues: if finish-start cannot be represented as
|
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471 | // by type index, then overflow may result.
|
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472 |
|
---|
473 | index len;
|
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474 | if ((finish - start) / stride < 0) {
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475 | // [start,finish) is empty according to the direction imposed by
|
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476 | // the stride.
|
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477 | len = 0;
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478 | } else {
|
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479 | // integral trick for ceiling((finish-start) / stride)
|
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480 | // taking into account signs.
|
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481 | index shrinkage = stride > 0 ? 1 : -1;
|
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482 | len = (finish - start + (stride - shrinkage)) / stride;
|
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483 | }
|
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484 |
|
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485 | // start marks the closed side of the range, so it must lie
|
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486 | // exactly in the set of legal indices
|
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487 | // with a special case for empty arrays
|
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488 | BOOST_ASSERT(index_bases[n] <= start &&
|
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489 | ((start <= index_bases[n]+index(extents[n])) ||
|
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490 | (start == index_bases[n] && extents[n] == 0)));
|
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491 |
|
---|
492 | #ifndef BOOST_DISABLE_ASSERTS
|
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493 | // finish marks the open side of the range, so it can go one past
|
---|
494 | // the "far side" of the range (the top if stride is positive, the bottom
|
---|
495 | // if stride is negative).
|
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496 | index bound_adjustment = stride < 0 ? 1 : 0;
|
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497 | BOOST_ASSERT(((index_bases[n] - bound_adjustment) <= finish) &&
|
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498 | (finish <= (index_bases[n] + index(extents[n]) - bound_adjustment)));
|
---|
499 | #endif // BOOST_DISABLE_ASSERTS
|
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500 |
|
---|
501 |
|
---|
502 | // the array data pointer is modified to account for non-zero
|
---|
503 | // bases during slicing (see [Garcia] for the math involved)
|
---|
504 | offset += start * strides[n];
|
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505 |
|
---|
506 | if (!current_range.is_degenerate()) {
|
---|
507 |
|
---|
508 | // The stride for each dimension is included into the
|
---|
509 | // strides for the array_view (see [Garcia] for the math involved).
|
---|
510 | new_strides[dim] = stride * strides[n];
|
---|
511 |
|
---|
512 | // calculate new extents
|
---|
513 | new_extents[dim] = len;
|
---|
514 | ++dim;
|
---|
515 | }
|
---|
516 | }
|
---|
517 | BOOST_ASSERT(dim == NDims);
|
---|
518 |
|
---|
519 | return
|
---|
520 | ArrayRef(base+offset,
|
---|
521 | new_extents,
|
---|
522 | new_strides);
|
---|
523 | }
|
---|
524 |
|
---|
525 |
|
---|
526 | };
|
---|
527 |
|
---|
528 | } // namespace multi_array
|
---|
529 | } // namespace detail
|
---|
530 |
|
---|
531 | } // namespace boost
|
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532 |
|
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533 | #endif // BASE_RG071801_HPP
|
---|