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1 /* |
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2 * Copyright (c) 2002-2004 Nokia Corporation and/or its subsidiary(-ies). |
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3 * All rights reserved. |
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4 * This component and the accompanying materials are made available |
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5 * under the terms of "Eclipse Public License v1.0" |
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6 * which accompanies this distribution, and is available |
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7 * at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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8 * |
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9 * Initial Contributors: |
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10 * Nokia Corporation - initial contribution. |
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11 * |
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12 * Contributors: |
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13 * |
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14 * Description: Iterates over a tree, breadth first |
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15 * |
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16 */ |
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17 |
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18 #ifndef XNNODEBREADTHFIRSTITERATOR_H |
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19 #define XNNODEBREADTHFIRSTITERATOR_H |
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20 |
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21 #include <e32base.h> |
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22 #include <e32cmn.h> |
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23 #include "xnchilditerator.h" |
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24 |
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25 // Constants |
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26 /** |
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27 * Queue granularity value |
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28 */ |
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29 const TInt KMemoryAloc = 128; |
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30 |
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31 template< class T > class CXnNodeBreadthFirstIterator : public CBase, |
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32 public MXnChildIterator |
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33 { |
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34 public: |
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35 |
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36 /** |
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37 * Two-phased constructor. |
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38 * @param aStartNode Object to iterate over |
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39 */ |
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40 static CXnNodeBreadthFirstIterator< T >* NewL( T& aStartNode ); |
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41 |
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42 /** |
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43 * Destructor. |
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44 */ |
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45 virtual ~CXnNodeBreadthFirstIterator(); |
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46 |
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47 /** |
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48 * Get the next iterator value. |
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49 * @return Next object or NULL if no more values. |
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50 */ |
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51 T* NextL(); |
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52 |
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53 /** |
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54 * Get the current iterator value. |
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55 * @return Current object |
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56 */ |
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57 T* Value(); |
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58 |
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59 /** |
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60 * Get the previous iterator value. Obsolete! |
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61 * @return NULL |
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62 */ |
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63 T* PreviousL(); |
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64 |
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65 /** |
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66 * Get the current iterator index. Obsolete! |
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67 * @return value 0 |
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68 */ |
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69 TUint Index() const; |
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70 |
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71 protected: |
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72 |
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73 /** |
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74 * C++ default constructor. |
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75 */ |
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76 CXnNodeBreadthFirstIterator( T* aStartNode ); |
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77 |
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78 /** |
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79 * 2nd phase constructor. |
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80 */ |
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81 void ConstructL(); |
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82 |
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83 private: |
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84 // Queue |
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85 RPointerArray< T > iQueue; |
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86 // Object to iterate over |
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87 T* iStart; |
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88 // Current object |
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89 T* iCurrent; |
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90 }; |
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91 |
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92 |
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93 // ----------------------------------------------------------------------------- |
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94 // CXnNodeBreadthFirstIterator< T >::NewL() |
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95 // ----------------------------------------------------------------------------- |
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96 // |
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97 template< class T > CXnNodeBreadthFirstIterator< T >* |
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98 CXnNodeBreadthFirstIterator< T >::NewL( T& aStartNode ) |
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99 { |
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100 CXnNodeBreadthFirstIterator< T >* p = |
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101 new ( ELeave )CXnNodeBreadthFirstIterator< T >( &aStartNode ); |
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102 CleanupStack::PushL( p ); |
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103 p->ConstructL(); |
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104 CleanupStack::Pop(); |
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105 return p; |
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106 } |
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107 |
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108 // ----------------------------------------------------------------------------- |
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109 // CXnNodeBreadthFirstIterator< T >::CXnNodeBreadthFirstIterator() |
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110 // C++ default constructor |
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111 // ----------------------------------------------------------------------------- |
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112 // |
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113 template< class T > |
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114 CXnNodeBreadthFirstIterator < T >::CXnNodeBreadthFirstIterator( |
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115 T* aStartNode ): iStart( aStartNode ), iCurrent( aStartNode ), |
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116 iQueue( KMemoryAloc ) |
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117 { |
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118 } |
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119 |
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120 // ----------------------------------------------------------------------------- |
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121 // CXnNodeBreadthFirstIterator< T >::~CXnNodeBreadthFirstIterator() |
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122 // C++ default destructor. |
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123 // ----------------------------------------------------------------------------- |
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124 // |
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125 template< class T > |
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126 CXnNodeBreadthFirstIterator< T >::~CXnNodeBreadthFirstIterator() |
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127 { |
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128 iQueue.Close(); |
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129 } |
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130 |
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131 // ----------------------------------------------------------------------------- |
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132 // CXnNodeBreadthFirstIterator< T >::ConstructL() |
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133 // Symbian 2nd phase constructor can leave. |
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134 // ----------------------------------------------------------------------------- |
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135 // |
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136 template< class T > void CXnNodeBreadthFirstIterator< T >::ConstructL() |
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137 { |
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138 iQueue.AppendL( iStart ); |
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139 } |
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140 |
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141 // ----------------------------------------------------------------------------- |
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142 // CXnNodeBreadthFirstIterator< T >::NextL() |
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143 // ----------------------------------------------------------------------------- |
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144 // |
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145 template< class T > T* CXnNodeBreadthFirstIterator< T >::NextL() |
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146 { |
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147 if( iQueue.Count() ) |
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148 { |
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149 // Dequeue |
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150 iCurrent = iQueue[0]; |
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151 iQueue.Remove(0); |
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152 |
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153 RPointerArray< T >& currentChildNodes = iCurrent->Children(); |
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154 TInt currentChildCount( currentChildNodes.Count() ); |
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155 |
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156 // Enqueue |
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157 for( TInt i = 0; i < currentChildCount; ++i ) |
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158 { |
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159 iQueue.AppendL( currentChildNodes[i] ); |
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160 } |
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161 } |
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162 else |
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163 { |
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164 iCurrent = NULL; |
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165 iQueue.Reset(); |
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166 iQueue.AppendL( iStart ); |
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167 } |
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168 return iCurrent; |
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169 } |
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170 |
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171 // ----------------------------------------------------------------------------- |
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172 // CXnNodeBreadthFirstIterator< T >::Value() |
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173 // ----------------------------------------------------------------------------- |
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174 // |
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175 template< class T > T* CXnNodeBreadthFirstIterator< T >::Value() |
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176 { |
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177 return iCurrent; |
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178 } |
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179 |
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180 // ----------------------------------------------------------------------------- |
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181 // CXnNodeBreadthFirstIterator< T >::PreviousL() |
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182 // ----------------------------------------------------------------------------- |
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183 // |
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184 template< class T > T* CXnNodeBreadthFirstIterator< T >::PreviousL() |
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185 { |
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186 return NULL; |
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187 } |
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188 |
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189 // ----------------------------------------------------------------------------- |
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190 // CXnNodeBreadthFirstIterator< T >::Index() |
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191 // ----------------------------------------------------------------------------- |
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192 // |
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193 template< class T > TUint CXnNodeBreadthFirstIterator< T >::Index() const |
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194 { |
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195 return 0; |
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196 } |
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197 |
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198 #endif //CXNNODEBREADTHFIRSTITERATOR_H |
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199 |
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200 // End of File |