1 | // -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- |
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2 | /*****************************************************************************\ |
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3 | * Computer Algebra System SINGULAR |
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4 | \*****************************************************************************/ |
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5 | /** @file Enumerator.h |
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6 | * |
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7 | * Abstract API for enumerators. |
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8 | * |
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9 | * ABSTRACT: Abstract interface for forward iteratable containers (enumerators) |
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10 | * of standalone objects (e.g. polynomials as sets of numbers), without any |
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11 | * knowledge of their internals. |
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12 | * |
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13 | * @author Oleksandr Motsak |
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14 | * |
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15 | * |
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16 | **/ |
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17 | /*****************************************************************************/ |
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18 | |
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19 | #ifndef ENUMERATOR_H |
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20 | #define ENUMERATOR_H |
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21 | |
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22 | /** @class IBaseEnumerator |
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23 | * |
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24 | * Base enumerator interface for simple iteration over a generic non-empty collection. |
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25 | * |
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26 | * Abstract API of enumerators for non-empty enumerable collections of standalone |
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27 | * objects. Inspired by IEnumerator from C#. Usage parrten can be as |
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28 | * follows: |
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29 | * |
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30 | * @code |
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31 | * IBaseEnumerator itr = ...; |
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32 | * itr.Reset(); // goes to the first element (must exist) |
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33 | * do |
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34 | * { |
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35 | * do something custom with itr... |
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36 | * } |
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37 | * while( itr.MoveNext() ) |
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38 | * @endcode |
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39 | * |
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40 | * Note that the first element must exist and available directly after Reset() call. |
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41 | * |
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42 | * @sa IEnumerator |
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43 | */ |
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44 | class IBaseEnumerator // IDisposable |
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45 | { |
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46 | public: |
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47 | /// Advances the enumerator to the next element of the collection. |
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48 | /// returns true if the enumerator was successfully advanced to the |
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49 | /// next element; |
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50 | /// false if the enumerator has passed the end of the collection. |
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51 | virtual bool MoveNext() = 0; |
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52 | |
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53 | /// Sets the enumerator to its initial position, which is at the first element in the collection. |
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54 | virtual void Reset() = 0; |
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55 | // virtual ~IEnumerator() {} // TODO: needed? |
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56 | }; |
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57 | |
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58 | |
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59 | /** @class IAccessor |
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60 | * |
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61 | * Templated accessor interface for accessing individual data (for instance, of an enumerator). |
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62 | * |
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63 | * T is the type of objects to access, available via the Current() method. |
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64 | * |
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65 | * @sa IBaseEnumerator |
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66 | */ |
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67 | template <typename T> |
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68 | class IAccessor // IDisposable |
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69 | { |
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70 | public: |
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71 | typedef T value_type; |
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72 | typedef value_type& reference; |
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73 | typedef const value_type& const_reference; |
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74 | |
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75 | /// Gets the current element in the collection (read and write). |
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76 | virtual reference Current() = 0; |
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77 | |
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78 | /// Gets the current element in the collection (read only). |
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79 | virtual const_reference Current() const = 0; |
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80 | }; |
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81 | |
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82 | /** @class IEnumerator |
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83 | * |
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84 | * Templated enumerator interface for simple iteration over a generic non-empty collection of T's. |
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85 | * |
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86 | * Abstract API of enumerators for non-empty enumerable collections of standalone |
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87 | * objects. Inspired by IEnumerator from C#. Usage parrten can be as |
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88 | * follows: |
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89 | * |
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90 | * @code |
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91 | * IEnumerator<T> itr = ...; |
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92 | * itr.Reset(); // goes to the first element (must exist) |
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93 | * do |
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94 | * { |
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95 | * use/change itr.Current()... |
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96 | * } |
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97 | * while( itr.MoveNext() ) |
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98 | * @endcode |
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99 | * |
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100 | * T is the type of objects to enumerate, available via Current() method |
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101 | * |
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102 | * @sa IBaseEnumerator |
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103 | */ |
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104 | template <typename T> |
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105 | class IEnumerator: public virtual IBaseEnumerator, public virtual IAccessor<T> |
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106 | { |
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107 | public: |
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108 | }; |
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109 | |
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110 | #if 0 |
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111 | // the following is not used for now // |
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112 | // the following is not used for now // |
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113 | // the following is not used for now // |
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114 | // the following is not used for now // |
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115 | // the following is not used for now // |
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116 | |
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117 | // include basic definitions |
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118 | //??// #include <iterator> |
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119 | |
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120 | /** @class IBaseIterator |
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121 | * |
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122 | * A base abstract iterator API with virtualized standard iterator operators |
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123 | * |
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124 | * Abstract API for iterators that should work with STL and BOOST. |
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125 | * |
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126 | * @sa STL iterators |
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127 | */ |
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128 | template <class A> |
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129 | class IBaseIterator //??// : public std::iterator<std::forward_iterator_tag, A> |
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130 | { |
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131 | public: |
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132 | typedef IBaseIterator<A> self; |
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133 | typedef self& self_reference; |
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134 | typedef const self_reference const_self_reference; |
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135 | |
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136 | virtual bool operator==(const_self_reference rhs) = 0; |
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137 | |
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138 | /// ++itr, goes to the next state, returns the new state |
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139 | virtual self_reference operator++() = 0; |
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140 | |
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141 | /// itr++, goes to the next state, returns the previous state |
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142 | virtual self_reference operator++(int) = 0; |
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143 | |
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144 | virtual A& operator*() = 0; |
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145 | virtual A* operator->() = 0; |
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146 | |
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147 | inline bool operator!=(const_self_reference rhs){ return !((*this) == rhs); } |
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148 | }; |
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149 | |
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150 | /** @class AIterator |
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151 | * |
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152 | * An abstract iterator with virtualized assigment operator and |
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153 | * constructors. |
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154 | * |
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155 | * Abstract API for iterators that should work with STL and BOOST. |
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156 | * |
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157 | * @sa STL iterators |
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158 | */ |
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159 | template <class A> |
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160 | class IIterator: public IBaseIterator<A> |
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161 | { |
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162 | public: |
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163 | typedef IIterator<A> self; |
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164 | typedef self& self_reference; |
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165 | typedef const self_reference const_self_reference; |
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166 | |
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167 | IIterator(){ void_constructor(); } |
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168 | |
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169 | IIterator(const_self_reference itr) { copy_constructor(itr); } |
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170 | |
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171 | virtual self_reference operator=(const_self_reference other) = 0; |
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172 | |
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173 | private: |
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174 | virtual void void_constructor() = 0; |
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175 | virtual void copy_constructor(const_self_reference itr) = 0; |
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176 | }; |
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177 | |
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178 | /** @class IContainer |
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179 | * |
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180 | * Container of standalone objects |
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181 | * |
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182 | * Abstract API for containers of objects and their iterators |
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183 | * |
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184 | * @sa STL containers and iterators |
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185 | */ |
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186 | template <class T> |
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187 | class IContainer |
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188 | { |
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189 | public: |
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190 | typedef T value_type; |
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191 | typedef value_type& reference; |
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192 | typedef const value_type& const_reference; |
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193 | //??// typedef std::size_t size_type; |
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194 | //??// virtual size_type size() const = 0; |
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195 | virtual bool empty() const = 0; |
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196 | |
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197 | typedef IIterator<reference> iterator; |
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198 | virtual iterator begin() = 0; |
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199 | virtual iterator end() = 0; |
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200 | |
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201 | typedef IIterator<const_reference> const_iterator; |
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202 | virtual const_iterator begin() const = 0; |
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203 | virtual const_iterator end() const = 0; |
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204 | }; |
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205 | #endif |
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206 | |
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207 | |
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208 | #endif |
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209 | /* #ifndef ENUMERATOR_H */ |
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210 | |
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211 | // Vi-modeline: vim: filetype=c:syntax:shiftwidth=2:tabstop=8:textwidth=0:expandtab |
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