1 | /** |
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2 | * @file rtems/score/rbtree.h |
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3 | * |
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4 | * @brief Constants and Structures Associated with the Red-Black Tree Handler |
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5 | * |
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6 | * This include file contains all the constants and structures associated |
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7 | * with the Red-Black Tree Handler. |
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8 | */ |
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9 | |
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10 | /* |
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11 | * Copyright (c) 2010 Gedare Bloom. |
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12 | * |
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13 | * The license and distribution terms for this file may be |
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14 | * found in the file LICENSE in this distribution or at |
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15 | * http://www.rtems.org/license/LICENSE. |
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16 | */ |
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17 | |
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18 | #ifndef _RTEMS_SCORE_RBTREE_H |
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19 | #define _RTEMS_SCORE_RBTREE_H |
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20 | |
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21 | #include <stddef.h> |
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22 | |
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23 | #include <rtems/score/address.h> |
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24 | |
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25 | #ifdef __cplusplus |
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26 | extern "C" { |
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27 | #endif |
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28 | |
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29 | /** |
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30 | * @defgroup ScoreRBTree Red-Black Tree Handler |
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31 | * |
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32 | * @ingroup Score |
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33 | * |
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34 | * The Red-Black Tree Handler is used to manage sets of entities. This handler |
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35 | * provides two data structures. The rbtree Node data structure is included |
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36 | * as the first part of every data structure that will be placed on |
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37 | * a RBTree. The second data structure is rbtree Control which is used |
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38 | * to manage a set of rbtree Nodes. |
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39 | */ |
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40 | /**@{*/ |
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41 | |
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42 | /** |
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43 | * @typedef RBTree_Node |
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44 | * |
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45 | * This type definition promotes the name for the RBTree Node used by |
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46 | * all RTEMS code. It is a separate type definition because a forward |
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47 | * reference is required to define it. See @ref RBTree_Node_struct for |
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48 | * detailed information. |
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49 | */ |
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50 | typedef struct RBTree_Node_struct RBTree_Node; |
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51 | |
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52 | /** |
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53 | * This enum type defines the colors available for the RBTree Nodes |
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54 | */ |
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55 | typedef enum { |
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56 | RBT_BLACK, |
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57 | RBT_RED |
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58 | } RBTree_Color; |
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59 | |
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60 | /** |
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61 | * @struct RBTree_Node_struct |
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62 | * |
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63 | * This is used to manage each element (node) which is placed |
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64 | * on a RBT. |
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65 | * |
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66 | * @note Typically, a more complicated structure will use the |
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67 | * rbtree package. The more complicated structure will |
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68 | * include a rbtree node as the first element in its |
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69 | * control structure. It will then call the rbtree package |
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70 | * with a pointer to that node element. The node pointer |
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71 | * and the higher level structure start at the same address |
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72 | * so the user can cast the pointers back and forth. |
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73 | * |
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74 | */ |
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75 | struct RBTree_Node_struct { |
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76 | /** This points to the node's parent */ |
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77 | RBTree_Node *parent; |
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78 | /** child[0] points to the left child, child[1] points to the right child */ |
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79 | RBTree_Node *child[2]; |
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80 | /** The color of the node. Either red or black */ |
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81 | RBTree_Color color; |
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82 | }; |
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83 | |
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84 | /** |
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85 | * This type indicates the direction. |
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86 | */ |
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87 | typedef enum { |
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88 | RBT_LEFT=0, |
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89 | RBT_RIGHT=1 |
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90 | } RBTree_Direction; |
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91 | |
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92 | /** |
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93 | * @brief Integer type for compare results. |
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94 | * |
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95 | * The type is large enough to represent pointers and 32-bit signed integers. |
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96 | * |
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97 | * @see RBTree_Compare. |
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98 | */ |
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99 | typedef long RBTree_Compare_result; |
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100 | |
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101 | /** |
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102 | * @brief Compares two red-black tree nodes. |
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103 | * |
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104 | * @param[in] first The first node. |
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105 | * @param[in] second The second node. |
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106 | * |
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107 | * @retval positive The key value of the first node is greater than the one of |
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108 | * the second node. |
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109 | * @retval 0 The key value of the first node is equal to the one of the second |
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110 | * node. |
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111 | * @retval negative The key value of the first node is less than the one of the |
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112 | * second node. |
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113 | */ |
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114 | typedef RBTree_Compare_result ( *RBTree_Compare )( |
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115 | const RBTree_Node *first, |
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116 | const RBTree_Node *second |
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117 | ); |
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118 | |
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119 | /** |
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120 | * @struct RBTree_Control |
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121 | * |
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122 | * This is used to manage a RBT. A rbtree consists of a tree of zero or more |
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123 | * nodes. |
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124 | * |
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125 | * @note This implementation does not require special checks for |
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126 | * manipulating the root element of the RBT. |
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127 | * To accomplish this the @a RBTree_Control structure can be overlaid |
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128 | * with a @ref RBTree_Node structure to act as a "dummy root", |
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129 | * which has a NULL parent and its left child is the root. |
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130 | */ |
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131 | |
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132 | /* the RBTree_Control is actually part of the RBTree structure as an |
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133 | * RBTree_Node. The mapping of fields from RBTree_Control to RBTree_Node are: |
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134 | * permanent_null == parent |
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135 | * root == left |
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136 | * first[0] == right |
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137 | */ |
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138 | typedef struct { |
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139 | /** This points to a NULL. Useful for finding the root. */ |
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140 | RBTree_Node *permanent_null; |
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141 | /** This points to the root node of the RBT. */ |
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142 | RBTree_Node *root; |
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143 | /** This points to the min and max nodes of this RBT. */ |
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144 | RBTree_Node *first[2]; |
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145 | } RBTree_Control; |
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146 | |
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147 | /** |
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148 | * @brief RBTree initializer for an empty rbtree with designator @a name. |
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149 | */ |
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150 | #define RBTREE_INITIALIZER_EMPTY( name ) \ |
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151 | { NULL, NULL, { NULL, NULL } } |
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152 | |
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153 | /** |
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154 | * @brief RBTree definition for an empty rbtree with designator @a name. |
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155 | */ |
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156 | #define RBTREE_DEFINE_EMPTY( name ) \ |
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157 | RBTree_Control name = RBTREE_INITIALIZER_EMPTY( name ) |
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158 | |
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159 | /** |
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160 | * @brief Tries to find a node for the specified key in the tree. |
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161 | * |
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162 | * @param[in] the_rbtree The red-black tree control. |
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163 | * @param[in] the_node A node specifying the key. |
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164 | * @param[in] compare The node compare function. |
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165 | * @param[in] is_unique If true, then return the first node with a key equal to |
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166 | * the one of the node specified if it exits, else return the last node if it |
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167 | * exists. |
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168 | * |
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169 | * @retval node A node corresponding to the key. If the tree is not unique |
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170 | * and contains duplicate keys, the set of duplicate keys acts as FIFO. |
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171 | * @retval NULL No node exists in the tree for the key. |
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172 | */ |
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173 | RBTree_Node *_RBTree_Find( |
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174 | const RBTree_Control *the_rbtree, |
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175 | const RBTree_Node *the_node, |
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176 | RBTree_Compare compare, |
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177 | bool is_unique |
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178 | ); |
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179 | |
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180 | /** |
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181 | * @brief Inserts the node into the red-black tree. |
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182 | * |
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183 | * In case the node is already a node of a tree, then this function yields |
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184 | * unpredictable results. |
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185 | * |
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186 | * @param[in] the_rbtree The red-black tree control. |
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187 | * @param[in] the_node The node to insert. |
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188 | * @param[in] compare The node compare function. |
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189 | * @param[in] is_unique If true, then reject nodes with a duplicate key, else |
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190 | * insert nodes in FIFO order in case the key value is equal to existing nodes. |
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191 | * |
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192 | * @retval NULL Successfully inserted. |
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193 | * @retval existing_node This is a unique insert and there exists a node with |
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194 | * an equal key in the tree already. |
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195 | */ |
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196 | RBTree_Node *_RBTree_Insert( |
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197 | RBTree_Control *the_rbtree, |
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198 | RBTree_Node *the_node, |
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199 | RBTree_Compare compare, |
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200 | bool is_unique |
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201 | ); |
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202 | |
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203 | /** |
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204 | * @brief Extracts (removes) the node from the red-black tree. |
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205 | * |
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206 | * This function does not set the node off-tree. In case this is desired, then |
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207 | * call _RBTree_Set_off_tree() after the extraction. |
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208 | * |
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209 | * In case the node to extract is not a node of the tree, then this function |
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210 | * yields unpredictable results. |
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211 | * |
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212 | * @param[in] the_rbtree The red-black tree control. |
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213 | * @param[in] the_node The node to extract. |
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214 | */ |
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215 | void _RBTree_Extract( |
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216 | RBTree_Control *the_rbtree, |
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217 | RBTree_Node *the_node |
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218 | ); |
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219 | |
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220 | /** |
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221 | * @brief Returns the in-order next node of a node. |
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222 | * |
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223 | * @param[in] node The node. |
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224 | * @param[in] dir The direction. |
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225 | * |
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226 | * @retval NULL The in-order next node does not exist. |
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227 | * @retval otherwise The next node. |
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228 | */ |
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229 | RBTree_Node *_RBTree_Next( |
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230 | const RBTree_Node *node, |
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231 | RBTree_Direction dir |
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232 | ); |
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233 | |
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234 | /** |
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235 | * @brief Sets a red-black tree node as off-tree. |
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236 | * |
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237 | * Do not use this function on nodes which are a part of a tree. |
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238 | * |
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239 | * @param[in] the_node The node to set off-tree. |
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240 | * |
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241 | * @see _RBTree_Is_node_off_tree(). |
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242 | */ |
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243 | RTEMS_INLINE_ROUTINE void _RBTree_Set_off_tree( RBTree_Node *the_node ) |
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244 | { |
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245 | the_node->parent = NULL; |
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246 | } |
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247 | |
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248 | /** |
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249 | * @brief Returns true, if this red-black tree node is off-tree, and false |
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250 | * otherwise. |
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251 | * |
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252 | * @param[in] the_node The node to test. |
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253 | * |
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254 | * @retval true The node is not a part of a tree (off-tree). |
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255 | * @retval false Otherwise. |
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256 | * |
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257 | * @see _RBTree_Set_off_tree(). |
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258 | */ |
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259 | RTEMS_INLINE_ROUTINE bool _RBTree_Is_node_off_tree( |
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260 | const RBTree_Node *the_node |
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261 | ) |
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262 | { |
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263 | return the_node->parent == NULL; |
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264 | } |
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265 | |
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266 | /** |
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267 | * @brief Returns a pointer to root node of the red-black tree. |
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268 | * |
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269 | * The root node may change after insert or extract operations. |
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270 | * |
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271 | * @param[in] the_rbtree The red-black tree control. |
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272 | * |
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273 | * @retval NULL The tree is empty. |
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274 | * @retval root The root node. |
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275 | * |
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276 | * @see _RBTree_Is_root(). |
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277 | */ |
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278 | RTEMS_INLINE_ROUTINE RBTree_Node *_RBTree_Root( |
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279 | const RBTree_Control *the_rbtree |
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280 | ) |
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281 | { |
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282 | return the_rbtree->root; |
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283 | } |
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284 | |
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285 | /** |
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286 | * @brief Return pointer to RBTree's first node. |
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287 | * |
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288 | * This function returns a pointer to the first node on @a the_rbtree, |
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289 | * where @a dir specifies whether to return the minimum (0) or maximum (1). |
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290 | */ |
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291 | RTEMS_INLINE_ROUTINE RBTree_Node *_RBTree_First( |
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292 | const RBTree_Control *the_rbtree, |
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293 | RBTree_Direction dir |
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294 | ) |
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295 | { |
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296 | return the_rbtree->first[dir]; |
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297 | } |
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298 | |
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299 | /** |
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300 | * @brief Returns a pointer to the parent of this node. |
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301 | * |
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302 | * The node must have a parent, thus it is invalid to use this function for the |
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303 | * root node or a node that is not part of a tree. To test for the root node |
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304 | * compare with _RBTree_Root() or use _RBTree_Is_root(). |
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305 | * |
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306 | * @param[in] the_node The node of interest. |
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307 | * |
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308 | * @retval parent The parent of this node. |
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309 | * @retval undefined The node is the root node or not part of a tree. |
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310 | */ |
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311 | RTEMS_INLINE_ROUTINE RBTree_Node *_RBTree_Parent( |
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312 | const RBTree_Node *the_node |
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313 | ) |
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314 | { |
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315 | return the_node->parent; |
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316 | } |
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317 | |
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318 | /** |
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319 | * @brief Return pointer to the left of this node. |
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320 | * |
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321 | * This function returns a pointer to the left node of this node. |
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322 | * |
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323 | * @param[in] the_node is the node to be operated upon. |
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324 | * |
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325 | * @return This method returns the left node on the rbtree. |
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326 | */ |
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327 | RTEMS_INLINE_ROUTINE RBTree_Node *_RBTree_Left( |
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328 | const RBTree_Node *the_node |
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329 | ) |
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330 | { |
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331 | return the_node->child[RBT_LEFT]; |
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332 | } |
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333 | |
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334 | /** |
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335 | * @brief Return pointer to the right of this node. |
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336 | * |
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337 | * This function returns a pointer to the right node of this node. |
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338 | * |
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339 | * @param[in] the_node is the node to be operated upon. |
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340 | * |
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341 | * @return This method returns the right node on the rbtree. |
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342 | */ |
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343 | RTEMS_INLINE_ROUTINE RBTree_Node *_RBTree_Right( |
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344 | const RBTree_Node *the_node |
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345 | ) |
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346 | { |
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347 | return the_node->child[RBT_RIGHT]; |
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348 | } |
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349 | |
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350 | /** |
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351 | * @brief Is the RBTree empty. |
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352 | * |
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353 | * This function returns true if there are no nodes on @a the_rbtree and |
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354 | * false otherwise. |
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355 | * |
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356 | * @param[in] the_rbtree is the rbtree to be operated upon. |
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357 | * |
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358 | * @retval true There are no nodes on @a the_rbtree. |
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359 | * @retval false There are nodes on @a the_rbtree. |
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360 | */ |
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361 | RTEMS_INLINE_ROUTINE bool _RBTree_Is_empty( |
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362 | const RBTree_Control *the_rbtree |
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363 | ) |
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364 | { |
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365 | return (the_rbtree->root == NULL); |
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366 | } |
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367 | |
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368 | /** |
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369 | * @brief Returns true if this node is the root node of a red-black tree, and |
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370 | * false otherwise. |
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371 | * |
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372 | * The root node may change after insert or extract operations. In case the |
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373 | * node is not a node of a tree, then this function yields unpredictable |
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374 | * results. |
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375 | * |
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376 | * @param[in] the_node The node of interest. |
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377 | * |
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378 | * @retval true The node is the root node. |
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379 | * @retval false Otherwise. |
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380 | * |
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381 | * @see _RBTree_Root(). |
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382 | */ |
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383 | RTEMS_INLINE_ROUTINE bool _RBTree_Is_root( |
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384 | const RBTree_Node *the_node |
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385 | ) |
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386 | { |
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387 | return _RBTree_Parent( _RBTree_Parent( the_node ) ) == NULL; |
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388 | } |
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389 | |
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390 | /** |
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391 | * @brief Finds the red-black tree control given a node in the tree. |
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392 | * |
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393 | * In case the node is not a node of a tree, then this function yields |
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394 | * unpredictable results. |
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395 | * |
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396 | * @param[in] the_node The node of interest. |
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397 | * |
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398 | * @return The red-black tree control of the node. |
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399 | */ |
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400 | RTEMS_INLINE_ROUTINE RBTree_Control *_RBTree_Find_control( |
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401 | const RBTree_Node *the_node |
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402 | ) |
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403 | { |
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404 | RBTree_Node *parent = the_node->parent; |
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405 | RBTree_Control *rbtree; |
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406 | |
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407 | do { |
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408 | rbtree = (RBTree_Control *) parent; |
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409 | parent = parent->parent; |
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410 | } while ( parent != NULL ); |
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411 | |
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412 | return rbtree; |
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413 | } |
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414 | |
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415 | /** |
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416 | * @brief Initialize this RBTree as empty. |
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417 | * |
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418 | * This routine initializes @a the_rbtree to contain zero nodes. |
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419 | */ |
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420 | RTEMS_INLINE_ROUTINE void _RBTree_Initialize_empty( |
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421 | RBTree_Control *the_rbtree |
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422 | ) |
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423 | { |
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424 | the_rbtree->permanent_null = NULL; |
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425 | the_rbtree->root = NULL; |
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426 | the_rbtree->first[RBT_LEFT] = NULL; |
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427 | the_rbtree->first[RBT_RIGHT] = NULL; |
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428 | } |
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429 | |
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430 | /** |
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431 | * @brief Returns the minimum node of the red-black tree. |
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432 | * |
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433 | * @param[in] the_rbtree The red-black tree control. |
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434 | * |
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435 | * @retval NULL The red-black tree is empty. |
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436 | * @retval node The minimum node. |
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437 | */ |
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438 | RTEMS_INLINE_ROUTINE RBTree_Node *_RBTree_Minimum( |
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439 | const RBTree_Control *the_rbtree |
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440 | ) |
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441 | { |
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442 | return _RBTree_First( the_rbtree, RBT_LEFT ); |
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443 | } |
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444 | |
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445 | /** |
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446 | * @brief Returns the maximum node of the red-black tree. |
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447 | * |
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448 | * @param[in] the_rbtree The red-black tree control. |
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449 | * |
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450 | * @retval NULL The red-black tree is empty. |
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451 | * @retval node The maximum node. |
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452 | */ |
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453 | RTEMS_INLINE_ROUTINE RBTree_Node *_RBTree_Maximum( |
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454 | const RBTree_Control *the_rbtree |
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455 | ) |
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456 | { |
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457 | return _RBTree_First( the_rbtree, RBT_RIGHT ); |
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458 | } |
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459 | |
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460 | /** |
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461 | * @brief Returns the predecessor of a node. |
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462 | * |
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463 | * @param[in] node is the node. |
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464 | * |
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465 | * @retval NULL The predecessor does not exist. Otherwise it returns |
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466 | * the predecessor node. |
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467 | */ |
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468 | RTEMS_INLINE_ROUTINE RBTree_Node *_RBTree_Predecessor( |
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469 | const RBTree_Node *node |
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470 | ) |
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471 | { |
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472 | return _RBTree_Next( node, RBT_LEFT ); |
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473 | } |
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474 | |
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475 | /** |
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476 | * @brief Returns the successor of a node. |
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477 | * |
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478 | * @param[in] node is the node. |
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479 | * |
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480 | * @retval NULL The successor does not exist. Otherwise the successor node. |
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481 | */ |
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482 | RTEMS_INLINE_ROUTINE RBTree_Node *_RBTree_Successor( |
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483 | const RBTree_Node *node |
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484 | ) |
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485 | { |
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486 | return _RBTree_Next( node, RBT_RIGHT ); |
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487 | } |
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488 | |
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489 | /**@}*/ |
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490 | |
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491 | #ifdef __cplusplus |
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492 | } |
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493 | #endif |
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494 | |
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495 | #endif |
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496 | /* end of include file */ |
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