1 | /** |
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2 | * @file |
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3 | * |
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4 | * @brief Chain Handler API |
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5 | */ |
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6 | |
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7 | /* |
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8 | * Copyright (c) 2010 embedded brains GmbH. |
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9 | * |
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10 | * COPYRIGHT (c) 1989-2014. |
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11 | * On-Line Applications Research Corporation (OAR). |
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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_CHAINIMPL_H |
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19 | #define _RTEMS_SCORE_CHAINIMPL_H |
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20 | |
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21 | #include <rtems/score/chain.h> |
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22 | #include <rtems/score/assert.h> |
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23 | |
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24 | #ifdef __cplusplus |
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25 | extern "C" { |
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26 | #endif |
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27 | |
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28 | /** |
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29 | * @addtogroup ScoreChain |
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30 | */ |
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31 | /**@{**/ |
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32 | |
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33 | /** |
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34 | * @brief Chain initializer for an empty chain with designator @a name. |
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35 | */ |
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36 | #define CHAIN_INITIALIZER_EMPTY(name) \ |
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37 | { { { &(name).Tail.Node, NULL }, &(name).Head.Node } } |
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38 | |
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39 | /** |
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40 | * @brief Chain initializer for a chain with one @a node. |
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41 | * |
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42 | * @see CHAIN_NODE_INITIALIZER_ONE_NODE_CHAIN(). |
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43 | */ |
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44 | #define CHAIN_INITIALIZER_ONE_NODE( node ) \ |
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45 | { { { (node), NULL }, (node) } } |
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46 | |
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47 | /** |
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48 | * @brief Chain node initializer for a @a chain containing exactly this node. |
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49 | * |
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50 | * @see CHAIN_INITIALIZER_ONE_NODE(). |
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51 | */ |
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52 | #define CHAIN_NODE_INITIALIZER_ONE_NODE_CHAIN( chain ) \ |
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53 | { &(chain)->Tail.Node, &(chain)->Head.Node } |
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54 | |
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55 | /** |
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56 | * @brief Chain definition for an empty chain with designator @a name. |
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57 | */ |
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58 | #define CHAIN_DEFINE_EMPTY(name) \ |
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59 | Chain_Control name = CHAIN_INITIALIZER_EMPTY(name) |
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60 | |
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61 | /** |
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62 | * @brief Initialize a chain header. |
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63 | * |
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64 | * This routine initializes @a the_chain structure to manage the |
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65 | * contiguous array of @a number_nodes nodes which starts at |
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66 | * @a starting_address. Each node is of @a node_size bytes. |
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67 | * |
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68 | * @param[in] the_chain specifies the chain to initialize |
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69 | * @param[in] starting_address is the starting address of the array |
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70 | * of elements |
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71 | * @param[in] number_nodes is the numebr of nodes that will be in the chain |
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72 | * @param[in] node_size is the size of each node |
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73 | */ |
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74 | void _Chain_Initialize( |
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75 | Chain_Control *the_chain, |
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76 | void *starting_address, |
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77 | size_t number_nodes, |
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78 | size_t node_size |
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79 | ); |
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80 | |
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81 | /** |
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82 | * @brief Returns the node count of the chain. |
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83 | * |
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84 | * @param[in] chain The chain. |
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85 | * |
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86 | * @note It does NOT disable interrupts to ensure the atomicity of the |
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87 | * operation. |
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88 | * |
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89 | * @retval The node count of the chain. |
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90 | */ |
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91 | size_t _Chain_Node_count_unprotected( const Chain_Control *chain ); |
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92 | |
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93 | /** |
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94 | * @brief Set off chain. |
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95 | * |
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96 | * This function sets the next field of the @a node to NULL indicating the @a |
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97 | * node is not part of a chain. |
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98 | * |
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99 | * @param[in] node the node set to off chain. |
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100 | */ |
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101 | RTEMS_INLINE_ROUTINE void _Chain_Set_off_chain( |
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102 | Chain_Node *node |
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103 | ) |
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104 | { |
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105 | node->next = NULL; |
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106 | #if defined(RTEMS_DEBUG) |
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107 | node->previous = NULL; |
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108 | #endif |
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109 | } |
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110 | |
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111 | /** |
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112 | * @brief Initializes a chain node. |
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113 | * |
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114 | * In debug configurations, the node is set off chain. In all other |
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115 | * configurations, this function does nothing. |
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116 | * |
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117 | * @param[in] the_node The chain node to initialize. |
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118 | */ |
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119 | RTEMS_INLINE_ROUTINE void _Chain_Initialize_node( Chain_Node *the_node ) |
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120 | { |
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121 | #if defined(RTEMS_DEBUG) |
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122 | _Chain_Set_off_chain( the_node ); |
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123 | #else |
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124 | (void) the_node; |
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125 | #endif |
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126 | } |
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127 | |
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128 | /** |
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129 | * @brief Is the node off chain. |
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130 | * |
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131 | * This function returns true if the @a node is not on a chain. A @a node is |
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132 | * off chain if the next field is set to NULL. |
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133 | * |
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134 | * @param[in] node is the node off chain. |
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135 | * |
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136 | * @retval true The @a node is off chain. |
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137 | * @retval false The @a node is not off chain. |
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138 | */ |
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139 | RTEMS_INLINE_ROUTINE bool _Chain_Is_node_off_chain( |
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140 | const Chain_Node *node |
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141 | ) |
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142 | { |
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143 | return node->next == NULL; |
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144 | } |
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145 | |
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146 | /** |
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147 | * @brief Are two nodes equal. |
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148 | * |
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149 | * This function returns true if @a left and @a right are equal, |
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150 | * and false otherwise. |
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151 | * |
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152 | * @param[in] left is the node on the left hand side of the comparison. |
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153 | * @param[in] right is the node on the left hand side of the comparison. |
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154 | * |
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155 | * @retval true @a left and @a right are equal. |
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156 | * @retval false @a left and @a right are not equal. |
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157 | */ |
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158 | RTEMS_INLINE_ROUTINE bool _Chain_Are_nodes_equal( |
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159 | const Chain_Node *left, |
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160 | const Chain_Node *right |
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161 | ) |
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162 | { |
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163 | return left == right; |
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164 | } |
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165 | |
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166 | /** |
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167 | * @brief Is the chain node pointer NULL. |
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168 | * |
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169 | * This function returns true if the_node is NULL and false otherwise. |
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170 | * |
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171 | * @param[in] the_node is the node pointer to check. |
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172 | * |
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173 | * @retval true @a the_node is @c NULL. |
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174 | * @retval false @a the_node is not @c NULL. |
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175 | */ |
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176 | RTEMS_INLINE_ROUTINE bool _Chain_Is_null_node( |
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177 | const Chain_Node *the_node |
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178 | ) |
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179 | { |
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180 | return (the_node == NULL); |
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181 | } |
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182 | |
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183 | /** |
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184 | * @brief Return pointer to chain head. |
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185 | * |
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186 | * This function returns a pointer to the head node on the chain. |
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187 | * |
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188 | * @param[in] the_chain is the chain to be operated upon. |
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189 | * |
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190 | * @return This method returns the permanent head node of the chain. |
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191 | */ |
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192 | RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Head( |
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193 | Chain_Control *the_chain |
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194 | ) |
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195 | { |
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196 | return &the_chain->Head.Node; |
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197 | } |
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198 | |
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199 | /** |
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200 | * @brief Return pointer to immutable chain head. |
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201 | * |
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202 | * This function returns a pointer to the head node on the chain. |
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203 | * |
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204 | * @param[in] the_chain is the chain to be operated upon. |
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205 | * |
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206 | * @return This method returns the permanent head node of the chain. |
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207 | */ |
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208 | RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_head( |
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209 | const Chain_Control *the_chain |
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210 | ) |
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211 | { |
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212 | return &the_chain->Head.Node; |
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213 | } |
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214 | |
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215 | /** |
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216 | * @brief Return pointer to chain tail. |
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217 | * |
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218 | * This function returns a pointer to the tail node on the chain. |
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219 | * |
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220 | * @param[in] the_chain is the chain to be operated upon. |
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221 | * |
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222 | * @return This method returns the permanent tail node of the chain. |
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223 | */ |
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224 | RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Tail( |
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225 | Chain_Control *the_chain |
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226 | ) |
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227 | { |
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228 | return &the_chain->Tail.Node; |
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229 | } |
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230 | |
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231 | /** |
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232 | * @brief Return pointer to immutable chain tail. |
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233 | * |
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234 | * This function returns a pointer to the tail node on the chain. |
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235 | * |
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236 | * @param[in] the_chain is the chain to be operated upon. |
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237 | * |
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238 | * @return This method returns the permanent tail node of the chain. |
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239 | */ |
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240 | RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_tail( |
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241 | const Chain_Control *the_chain |
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242 | ) |
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243 | { |
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244 | return &the_chain->Tail.Node; |
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245 | } |
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246 | |
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247 | /** |
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248 | * @brief Return pointer to chain's first node. |
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249 | * |
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250 | * This function returns a pointer to the first node on the chain after the |
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251 | * head. |
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252 | * |
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253 | * @param[in] the_chain is the chain to be operated upon. |
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254 | * |
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255 | * @return This method returns the first node of the chain. |
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256 | */ |
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257 | RTEMS_INLINE_ROUTINE Chain_Node *_Chain_First( |
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258 | const Chain_Control *the_chain |
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259 | ) |
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260 | { |
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261 | return _Chain_Immutable_head( the_chain )->next; |
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262 | } |
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263 | |
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264 | /** |
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265 | * @brief Return pointer to immutable chain's first node. |
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266 | * |
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267 | * This function returns a pointer to the first node on the chain after the |
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268 | * head. |
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269 | * |
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270 | * @param[in] the_chain is the chain to be operated upon. |
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271 | * |
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272 | * @return This method returns the first node of the chain. |
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273 | */ |
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274 | RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_first( |
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275 | const Chain_Control *the_chain |
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276 | ) |
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277 | { |
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278 | return _Chain_Immutable_head( the_chain )->next; |
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279 | } |
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280 | |
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281 | /** |
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282 | * @brief Return pointer to chain's last node. |
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283 | * |
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284 | * This function returns a pointer to the last node on the chain just before |
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285 | * the tail. |
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286 | * |
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287 | * @param[in] the_chain is the chain to be operated upon. |
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288 | * |
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289 | * @return This method returns the last node of the chain. |
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290 | */ |
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291 | RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Last( |
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292 | const Chain_Control *the_chain |
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293 | ) |
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294 | { |
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295 | return _Chain_Immutable_tail( the_chain )->previous; |
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296 | } |
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297 | |
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298 | /** |
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299 | * @brief Return pointer to immutable chain's last node. |
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300 | * |
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301 | * This function returns a pointer to the last node on the chain just before |
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302 | * the tail. |
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303 | * |
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304 | * @param[in] the_chain is the chain to be operated upon. |
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305 | * |
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306 | * @return This method returns the last node of the chain. |
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307 | */ |
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308 | RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_last( |
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309 | const Chain_Control *the_chain |
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310 | ) |
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311 | { |
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312 | return _Chain_Immutable_tail( the_chain )->previous; |
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313 | } |
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314 | |
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315 | /** |
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316 | * @brief Return pointer the next node from this node. |
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317 | * |
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318 | * This function returns a pointer to the next node after this node. |
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319 | * |
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320 | * @param[in] the_node is the node to be operated upon. |
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321 | * |
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322 | * @return This method returns the next node on the chain. |
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323 | */ |
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324 | RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Next( |
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325 | const Chain_Node *the_node |
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326 | ) |
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327 | { |
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328 | return the_node->next; |
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329 | } |
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330 | |
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331 | /** |
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332 | * @brief Return pointer the immutable next node from this node. |
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333 | * |
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334 | * This function returns a pointer to the next node after this node. |
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335 | * |
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336 | * @param[in] the_node is the node to be operated upon. |
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337 | * |
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338 | * @return This method returns the next node on the chain. |
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339 | */ |
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340 | RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_next( |
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341 | const Chain_Node *the_node |
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342 | ) |
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343 | { |
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344 | return the_node->next; |
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345 | } |
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346 | |
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347 | /** |
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348 | * @brief Return pointer the previous node from this node. |
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349 | * |
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350 | * This function returns a pointer to the previous node on this chain. |
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351 | * |
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352 | * @param[in] the_node is the node to be operated upon. |
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353 | * |
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354 | * @return This method returns the previous node on the chain. |
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355 | */ |
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356 | RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Previous( |
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357 | const Chain_Node *the_node |
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358 | ) |
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359 | { |
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360 | return the_node->previous; |
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361 | } |
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362 | |
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363 | /** |
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364 | * @brief Return pointer the immutable previous node from this node. |
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365 | * |
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366 | * This function returns a pointer to the previous node on this chain. |
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367 | * |
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368 | * @param[in] the_node is the node to be operated upon. |
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369 | * |
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370 | * @return This method returns the previous node on the chain. |
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371 | */ |
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372 | RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_previous( |
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373 | const Chain_Node *the_node |
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374 | ) |
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375 | { |
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376 | return the_node->previous; |
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377 | } |
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378 | |
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379 | /** |
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380 | * @brief Is the chain empty. |
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381 | * |
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382 | * This function returns true if there a no nodes on @a the_chain and |
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383 | * false otherwise. |
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384 | * |
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385 | * @param[in] the_chain is the chain to be operated upon. |
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386 | * |
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387 | * @retval true There are no nodes on @a the_chain. |
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388 | * @retval false There are nodes on @a the_chain. |
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389 | */ |
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390 | RTEMS_INLINE_ROUTINE bool _Chain_Is_empty( |
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391 | const Chain_Control *the_chain |
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392 | ) |
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393 | { |
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394 | return _Chain_Immutable_first( the_chain ) |
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395 | == _Chain_Immutable_tail( the_chain ); |
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396 | } |
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397 | |
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398 | /** |
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399 | * @brief Is this the first node on the chain. |
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400 | * |
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401 | * This function returns true if the_node is the first node on a chain and |
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402 | * false otherwise. |
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403 | * |
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404 | * @param[in] the_node is the node the caller wants to know if it is |
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405 | * the first node on a chain. |
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406 | * |
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407 | * @retval true @a the_node is the first node on a chain. |
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408 | * @retval false @a the_node is not the first node on a chain. |
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409 | */ |
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410 | RTEMS_INLINE_ROUTINE bool _Chain_Is_first( |
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411 | const Chain_Node *the_node |
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412 | ) |
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413 | { |
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414 | return (the_node->previous->previous == NULL); |
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415 | } |
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416 | |
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417 | /** |
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418 | * @brief Is this the last node on the chain. |
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419 | * |
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420 | * This function returns true if @a the_node is the last node on a chain and |
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421 | * false otherwise. |
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422 | * |
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423 | * @param[in] the_node is the node to check as the last node. |
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424 | * |
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425 | * @retval true @a the_node is the last node on a chain. |
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426 | * @retval false @a the_node is not the last node on a chain. |
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427 | */ |
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428 | RTEMS_INLINE_ROUTINE bool _Chain_Is_last( |
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429 | const Chain_Node *the_node |
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430 | ) |
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431 | { |
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432 | return (the_node->next->next == NULL); |
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433 | } |
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434 | |
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435 | /** |
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436 | * @brief Does this chain have only one node. |
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437 | * |
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438 | * This function returns true if there is only one node on @a the_chain and |
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439 | * false otherwise. |
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440 | * |
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441 | * @param[in] the_chain is the chain to be operated upon. |
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442 | * |
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443 | * @return This function returns true if there is only one node on |
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444 | * @a the_chain and false otherwise. |
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445 | * |
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446 | * @retval true There is only one node on @a the_chain. |
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447 | * @retval false There is more than one node on @a the_chain. |
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448 | */ |
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449 | RTEMS_INLINE_ROUTINE bool _Chain_Has_only_one_node( |
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450 | const Chain_Control *the_chain |
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451 | ) |
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452 | { |
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453 | return _Chain_Immutable_first( the_chain ) |
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454 | == _Chain_Immutable_last( the_chain ); |
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455 | } |
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456 | |
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457 | /** |
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458 | * @brief Is this node the chain head. |
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459 | * |
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460 | * This function returns true if @a the_node is the head of @a the_chain and |
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461 | * false otherwise. |
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462 | * |
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463 | * @param[in] the_chain is the chain to be operated upon. |
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464 | * @param[in] the_node is the node to check for being the Chain Head. |
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465 | * |
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466 | * @retval true @a the_node is the head of @a the_chain. |
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467 | * @retval false @a the_node is not the head of @a the_chain. |
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468 | */ |
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469 | RTEMS_INLINE_ROUTINE bool _Chain_Is_head( |
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470 | const Chain_Control *the_chain, |
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471 | const Chain_Node *the_node |
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472 | ) |
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473 | { |
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474 | return (the_node == _Chain_Immutable_head( the_chain )); |
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475 | } |
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476 | |
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477 | /** |
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478 | * @brief Is this node the chail tail. |
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479 | * |
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480 | * This function returns true if @a the_node is the tail of @a the_chain and |
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481 | * false otherwise. |
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482 | * |
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483 | * @param[in] the_chain is the chain to be operated upon. |
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484 | * @param[in] the_node is the node to check for being the Chain Tail. |
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485 | * |
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486 | * @retval true @a the_node is the tail of @a the_chain. |
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487 | * @retval false @a the_node is not the tail of @a the_chain. |
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488 | */ |
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489 | RTEMS_INLINE_ROUTINE bool _Chain_Is_tail( |
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490 | const Chain_Control *the_chain, |
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491 | const Chain_Node *the_node |
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492 | ) |
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493 | { |
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494 | return (the_node == _Chain_Immutable_tail( the_chain )); |
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495 | } |
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496 | |
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497 | /** |
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498 | * @brief Initialize this chain as empty. |
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499 | * |
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500 | * This routine initializes the specified chain to contain zero nodes. |
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501 | * |
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502 | * @param[in] the_chain is the chain to be initialized. |
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503 | */ |
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504 | RTEMS_INLINE_ROUTINE void _Chain_Initialize_empty( |
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505 | Chain_Control *the_chain |
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506 | ) |
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507 | { |
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508 | Chain_Node *head; |
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509 | Chain_Node *tail; |
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510 | |
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511 | _Assert( the_chain != NULL ); |
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512 | |
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513 | head = _Chain_Head( the_chain ); |
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514 | tail = _Chain_Tail( the_chain ); |
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515 | |
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516 | head->next = tail; |
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517 | head->previous = NULL; |
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518 | tail->previous = head; |
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519 | } |
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520 | |
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521 | /** |
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522 | * @brief Initializes this chain to contain exactly the specified node. |
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523 | * |
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524 | * @param[in] the_chain The chain control. |
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525 | * @param[in] the_node The one and only node. |
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526 | */ |
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527 | RTEMS_INLINE_ROUTINE void _Chain_Initialize_one( |
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528 | Chain_Control *the_chain, |
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529 | Chain_Node *the_node |
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530 | ) |
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531 | { |
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532 | Chain_Node *head; |
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533 | Chain_Node *tail; |
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534 | |
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535 | _Assert( _Chain_Is_node_off_chain( the_node ) ); |
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536 | |
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537 | head = _Chain_Head( the_chain ); |
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538 | tail = _Chain_Tail( the_chain ); |
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539 | |
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540 | the_node->next = tail; |
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541 | the_node->previous = head; |
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542 | |
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543 | head->next = the_node; |
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544 | head->previous = NULL; |
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545 | tail->previous = the_node; |
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546 | } |
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547 | |
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548 | /** |
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549 | * @brief Extract this node (unprotected). |
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550 | * |
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551 | * This routine extracts the_node from the chain on which it resides. |
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552 | * It does NOT disable interrupts to ensure the atomicity of the |
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553 | * extract operation. |
---|
554 | * |
---|
555 | * @param[in] the_node is the node to be extracted. |
---|
556 | */ |
---|
557 | RTEMS_INLINE_ROUTINE void _Chain_Extract_unprotected( |
---|
558 | Chain_Node *the_node |
---|
559 | ) |
---|
560 | { |
---|
561 | Chain_Node *next; |
---|
562 | Chain_Node *previous; |
---|
563 | |
---|
564 | _Assert( !_Chain_Is_node_off_chain( the_node ) ); |
---|
565 | |
---|
566 | next = the_node->next; |
---|
567 | previous = the_node->previous; |
---|
568 | next->previous = previous; |
---|
569 | previous->next = next; |
---|
570 | |
---|
571 | #if defined(RTEMS_DEBUG) |
---|
572 | _Chain_Set_off_chain( the_node ); |
---|
573 | #endif |
---|
574 | } |
---|
575 | |
---|
576 | /** |
---|
577 | * @brief Get the first node (unprotected). |
---|
578 | * |
---|
579 | * This function removes the first node from the_chain and returns |
---|
580 | * a pointer to that node. It does NOT disable interrupts to ensure |
---|
581 | * the atomicity of the get operation. |
---|
582 | * |
---|
583 | * @param[in] the_chain is the chain to attempt to get the first node from. |
---|
584 | * |
---|
585 | * @return This method returns the first node on the chain even if it is |
---|
586 | * the Chain Tail. |
---|
587 | * |
---|
588 | * @note This routine assumes that there is at least one node on the chain |
---|
589 | * and always returns a node even if it is the Chain Tail. |
---|
590 | */ |
---|
591 | RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Get_first_unprotected( |
---|
592 | Chain_Control *the_chain |
---|
593 | ) |
---|
594 | { |
---|
595 | Chain_Node *head; |
---|
596 | Chain_Node *old_first; |
---|
597 | Chain_Node *new_first; |
---|
598 | |
---|
599 | _Assert( !_Chain_Is_empty( the_chain ) ); |
---|
600 | |
---|
601 | head = _Chain_Head( the_chain ); |
---|
602 | old_first = head->next; |
---|
603 | new_first = old_first->next; |
---|
604 | |
---|
605 | head->next = new_first; |
---|
606 | new_first->previous = head; |
---|
607 | |
---|
608 | #if defined(RTEMS_DEBUG) |
---|
609 | _Chain_Set_off_chain( old_first ); |
---|
610 | #endif |
---|
611 | |
---|
612 | return old_first; |
---|
613 | } |
---|
614 | |
---|
615 | /** |
---|
616 | * @brief Get the first node (unprotected). |
---|
617 | * |
---|
618 | * This function removes the first node from the_chain and returns |
---|
619 | * a pointer to that node. If the_chain is empty, then NULL is returned. |
---|
620 | * |
---|
621 | * @param[in] the_chain is the chain to attempt to get the first node from. |
---|
622 | * |
---|
623 | * @return This method returns the first node on the chain or NULL if the |
---|
624 | * chain is empty. |
---|
625 | * |
---|
626 | * @note It does NOT disable interrupts to ensure the atomicity of the |
---|
627 | * get operation. |
---|
628 | */ |
---|
629 | RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Get_unprotected( |
---|
630 | Chain_Control *the_chain |
---|
631 | ) |
---|
632 | { |
---|
633 | if ( !_Chain_Is_empty(the_chain)) |
---|
634 | return _Chain_Get_first_unprotected(the_chain); |
---|
635 | else |
---|
636 | return NULL; |
---|
637 | } |
---|
638 | |
---|
639 | /** |
---|
640 | * @brief Insert a node (unprotected). |
---|
641 | * |
---|
642 | * This routine inserts the_node on a chain immediately following |
---|
643 | * after_node. |
---|
644 | * |
---|
645 | * @param[in] after_node is the node which will precede @a the_node on the |
---|
646 | * chain. |
---|
647 | * @param[in] the_node is the node to be inserted. |
---|
648 | * |
---|
649 | * @note It does NOT disable interrupts to ensure the atomicity |
---|
650 | * of the extract operation. |
---|
651 | */ |
---|
652 | RTEMS_INLINE_ROUTINE void _Chain_Insert_unprotected( |
---|
653 | Chain_Node *after_node, |
---|
654 | Chain_Node *the_node |
---|
655 | ) |
---|
656 | { |
---|
657 | Chain_Node *before_node; |
---|
658 | |
---|
659 | _Assert( _Chain_Is_node_off_chain( the_node ) ); |
---|
660 | |
---|
661 | the_node->previous = after_node; |
---|
662 | before_node = after_node->next; |
---|
663 | after_node->next = the_node; |
---|
664 | the_node->next = before_node; |
---|
665 | before_node->previous = the_node; |
---|
666 | } |
---|
667 | |
---|
668 | /** |
---|
669 | * @brief Append a node (unprotected). |
---|
670 | * |
---|
671 | * This routine appends the_node onto the end of the_chain. |
---|
672 | * |
---|
673 | * @param[in] the_chain is the chain to be operated upon. |
---|
674 | * @param[in] the_node is the node to be appended. |
---|
675 | * |
---|
676 | * @note It does NOT disable interrupts to ensure the atomicity of the |
---|
677 | * append operation. |
---|
678 | */ |
---|
679 | RTEMS_INLINE_ROUTINE void _Chain_Append_unprotected( |
---|
680 | Chain_Control *the_chain, |
---|
681 | Chain_Node *the_node |
---|
682 | ) |
---|
683 | { |
---|
684 | Chain_Node *tail; |
---|
685 | Chain_Node *old_last; |
---|
686 | |
---|
687 | _Assert( _Chain_Is_node_off_chain( the_node ) ); |
---|
688 | |
---|
689 | tail = _Chain_Tail( the_chain ); |
---|
690 | old_last = tail->previous; |
---|
691 | |
---|
692 | the_node->next = tail; |
---|
693 | tail->previous = the_node; |
---|
694 | old_last->next = the_node; |
---|
695 | the_node->previous = old_last; |
---|
696 | } |
---|
697 | |
---|
698 | /** |
---|
699 | * @brief Append a node on the end of a chain if the node is in the off chain |
---|
700 | * state (unprotected). |
---|
701 | * |
---|
702 | * @note It does NOT disable interrupts to ensure the atomicity of the |
---|
703 | * append operation. |
---|
704 | * |
---|
705 | * @see _Chain_Append_unprotected() and _Chain_Is_node_off_chain(). |
---|
706 | */ |
---|
707 | RTEMS_INLINE_ROUTINE void _Chain_Append_if_is_off_chain_unprotected( |
---|
708 | Chain_Control *the_chain, |
---|
709 | Chain_Node *the_node |
---|
710 | ) |
---|
711 | { |
---|
712 | if ( _Chain_Is_node_off_chain( the_node ) ) { |
---|
713 | _Chain_Append_unprotected( the_chain, the_node ); |
---|
714 | } |
---|
715 | } |
---|
716 | |
---|
717 | /** |
---|
718 | * @brief Prepend a node (unprotected). |
---|
719 | * |
---|
720 | * This routine prepends the_node onto the front of the_chain. |
---|
721 | * |
---|
722 | * @param[in] the_chain is the chain to be operated upon. |
---|
723 | * @param[in] the_node is the node to be prepended. |
---|
724 | * |
---|
725 | * @note It does NOT disable interrupts to ensure the atomicity of the |
---|
726 | * prepend operation. |
---|
727 | */ |
---|
728 | RTEMS_INLINE_ROUTINE void _Chain_Prepend_unprotected( |
---|
729 | Chain_Control *the_chain, |
---|
730 | Chain_Node *the_node |
---|
731 | ) |
---|
732 | { |
---|
733 | _Chain_Insert_unprotected(_Chain_Head(the_chain), the_node); |
---|
734 | } |
---|
735 | |
---|
736 | /** |
---|
737 | * @brief Append a node and check if the chain was empty before (unprotected). |
---|
738 | * |
---|
739 | * This routine appends the_node onto the end of the_chain. |
---|
740 | * |
---|
741 | * @param[in] the_chain is the chain to be operated upon. |
---|
742 | * @param[in] the_node is the node to be appended. |
---|
743 | * |
---|
744 | * @note It does NOT disable interrupts to ensure the atomicity of the |
---|
745 | * append operation. |
---|
746 | * |
---|
747 | * @retval true The chain was empty before. |
---|
748 | * @retval false The chain contained at least one node before. |
---|
749 | */ |
---|
750 | RTEMS_INLINE_ROUTINE bool _Chain_Append_with_empty_check_unprotected( |
---|
751 | Chain_Control *the_chain, |
---|
752 | Chain_Node *the_node |
---|
753 | ) |
---|
754 | { |
---|
755 | bool was_empty = _Chain_Is_empty( the_chain ); |
---|
756 | |
---|
757 | _Chain_Append_unprotected( the_chain, the_node ); |
---|
758 | |
---|
759 | return was_empty; |
---|
760 | } |
---|
761 | |
---|
762 | /** |
---|
763 | * @brief Prepend a node and check if the chain was empty before (unprotected). |
---|
764 | * |
---|
765 | * This routine prepends the_node onto the front of the_chain. |
---|
766 | * |
---|
767 | * @param[in] the_chain is the chain to be operated upon. |
---|
768 | * @param[in] the_node is the node to be prepended. |
---|
769 | * |
---|
770 | * @note It does NOT disable interrupts to ensure the atomicity of the |
---|
771 | * prepend operation. |
---|
772 | * |
---|
773 | * @retval true The chain was empty before. |
---|
774 | * @retval false The chain contained at least one node before. |
---|
775 | */ |
---|
776 | RTEMS_INLINE_ROUTINE bool _Chain_Prepend_with_empty_check_unprotected( |
---|
777 | Chain_Control *the_chain, |
---|
778 | Chain_Node *the_node |
---|
779 | ) |
---|
780 | { |
---|
781 | bool was_empty = _Chain_Is_empty( the_chain ); |
---|
782 | |
---|
783 | _Chain_Prepend_unprotected( the_chain, the_node ); |
---|
784 | |
---|
785 | return was_empty; |
---|
786 | } |
---|
787 | |
---|
788 | /** |
---|
789 | * @brief Get the first node and check if the chain is empty afterwards |
---|
790 | * (unprotected). |
---|
791 | * |
---|
792 | * This function removes the first node from the_chain and returns |
---|
793 | * a pointer to that node in @a the_node. If the_chain is empty, then NULL is |
---|
794 | * returned. |
---|
795 | * |
---|
796 | * @param[in] the_chain is the chain to attempt to get the first node from. |
---|
797 | * @param[out] the_node is the first node on the chain or NULL if the chain is |
---|
798 | * empty. |
---|
799 | * |
---|
800 | * @note It does NOT disable interrupts to ensure the atomicity of the |
---|
801 | * get operation. |
---|
802 | * |
---|
803 | * @retval true The chain is empty now. |
---|
804 | * @retval false The chain contains at least one node now. |
---|
805 | */ |
---|
806 | RTEMS_INLINE_ROUTINE bool _Chain_Get_with_empty_check_unprotected( |
---|
807 | Chain_Control *the_chain, |
---|
808 | Chain_Node **the_node |
---|
809 | ) |
---|
810 | { |
---|
811 | bool is_empty_now = true; |
---|
812 | Chain_Node *head = _Chain_Head( the_chain ); |
---|
813 | Chain_Node *tail = _Chain_Tail( the_chain ); |
---|
814 | Chain_Node *old_first = head->next; |
---|
815 | |
---|
816 | if ( old_first != tail ) { |
---|
817 | Chain_Node *new_first = old_first->next; |
---|
818 | |
---|
819 | head->next = new_first; |
---|
820 | new_first->previous = head; |
---|
821 | |
---|
822 | *the_node = old_first; |
---|
823 | |
---|
824 | is_empty_now = new_first == tail; |
---|
825 | } else |
---|
826 | *the_node = NULL; |
---|
827 | |
---|
828 | return is_empty_now; |
---|
829 | } |
---|
830 | |
---|
831 | /** |
---|
832 | * @brief Chain node order. |
---|
833 | * |
---|
834 | * @param[in] left The left hand side. |
---|
835 | * @param[in] right The right hand side. |
---|
836 | * |
---|
837 | * @retval true According to the order the left node precedes the right node. |
---|
838 | * @retval false Otherwise. |
---|
839 | */ |
---|
840 | typedef bool ( *Chain_Node_order )( |
---|
841 | const void *left, |
---|
842 | const Chain_Node *right |
---|
843 | ); |
---|
844 | |
---|
845 | /** |
---|
846 | * @brief Inserts a node into the chain according to the order relation. |
---|
847 | * |
---|
848 | * After the operation the chain contains the node to insert and the order |
---|
849 | * relation holds for all nodes from the head up to the inserted node. Nodes |
---|
850 | * after the inserted node are not moved. |
---|
851 | * |
---|
852 | * @param[in] the_chain The chain. |
---|
853 | * @param[in] to_insert The node to insert. |
---|
854 | * @param[in] left The left hand side passed to the order relation. It must |
---|
855 | * correspond to the node to insert. The separate left hand side parameter |
---|
856 | * may help the compiler to generate better code if it is stored in a local |
---|
857 | * variable. |
---|
858 | * @param[in] order The order relation. |
---|
859 | */ |
---|
860 | RTEMS_INLINE_ROUTINE void _Chain_Insert_ordered_unprotected( |
---|
861 | Chain_Control *the_chain, |
---|
862 | Chain_Node *to_insert, |
---|
863 | const void *left, |
---|
864 | Chain_Node_order order |
---|
865 | ) |
---|
866 | { |
---|
867 | const Chain_Node *tail = _Chain_Immutable_tail( the_chain ); |
---|
868 | Chain_Node *next = _Chain_First( the_chain ); |
---|
869 | |
---|
870 | while ( next != tail && !( *order )( left, next ) ) { |
---|
871 | next = _Chain_Next( next ); |
---|
872 | } |
---|
873 | |
---|
874 | _Chain_Insert_unprotected( _Chain_Previous( next ), to_insert ); |
---|
875 | } |
---|
876 | |
---|
877 | /** |
---|
878 | * @brief The chain iterator direction. |
---|
879 | */ |
---|
880 | typedef enum { |
---|
881 | /** |
---|
882 | * @brief Iteration from head to tail. |
---|
883 | */ |
---|
884 | CHAIN_ITERATOR_FORWARD, |
---|
885 | |
---|
886 | /** |
---|
887 | * @brief Iteration from tail to head. |
---|
888 | */ |
---|
889 | CHAIN_ITERATOR_BACKWARD |
---|
890 | } Chain_Iterator_direction; |
---|
891 | |
---|
892 | /** |
---|
893 | * @brief A chain iterator which is updated during node extraction if it is |
---|
894 | * properly registered. |
---|
895 | * |
---|
896 | * @see _Chain_Iterator_initialize(). |
---|
897 | */ |
---|
898 | typedef struct { |
---|
899 | /** |
---|
900 | * @brief Node for registration. |
---|
901 | * |
---|
902 | * Used during _Chain_Iterator_initialize() and _Chain_Iterator_destroy(). |
---|
903 | */ |
---|
904 | Chain_Node Registry_node; |
---|
905 | |
---|
906 | /** |
---|
907 | * @brief The direction of this iterator. |
---|
908 | * |
---|
909 | * Immutable after initialization via _Chain_Iterator_initialize(). |
---|
910 | */ |
---|
911 | Chain_Iterator_direction direction; |
---|
912 | |
---|
913 | /** |
---|
914 | * @brief The current position of this iterator. |
---|
915 | * |
---|
916 | * The position is initialized via _Chain_Iterator_initialize(). It must be |
---|
917 | * explicitly set after one valid iteration step, e.g. in case a next node in |
---|
918 | * the iterator direction existed. It is updated through the registration in |
---|
919 | * case a node is extracted via _Chain_Iterator_registry_update(). |
---|
920 | */ |
---|
921 | Chain_Node *position; |
---|
922 | } Chain_Iterator; |
---|
923 | |
---|
924 | /** |
---|
925 | * @brief A registry for chain iterators. |
---|
926 | * |
---|
927 | * Should be attached to a chain control to enable safe iteration through a |
---|
928 | * chain in case of concurrent node extractions. |
---|
929 | */ |
---|
930 | typedef struct { |
---|
931 | Chain_Control Iterators; |
---|
932 | } Chain_Iterator_registry; |
---|
933 | |
---|
934 | /** |
---|
935 | * @brief Chain iterator registry initializer for static initialization. |
---|
936 | * |
---|
937 | * @param name The designator of the chain iterator registry. |
---|
938 | */ |
---|
939 | #define CHAIN_ITERATOR_REGISTRY_INITIALIZER( name ) \ |
---|
940 | { CHAIN_INITIALIZER_EMPTY( name.Iterators ) } |
---|
941 | |
---|
942 | /** |
---|
943 | * @brief Initializes a chain iterator registry. |
---|
944 | */ |
---|
945 | RTEMS_INLINE_ROUTINE void _Chain_Iterator_registry_initialize( |
---|
946 | Chain_Iterator_registry *the_registry |
---|
947 | ) |
---|
948 | { |
---|
949 | _Chain_Initialize_empty( &the_registry->Iterators ); |
---|
950 | } |
---|
951 | |
---|
952 | /** |
---|
953 | * @brief Updates all iterators present in the chain iterator registry in case |
---|
954 | * of a node extraction. |
---|
955 | * |
---|
956 | * Must be called before _Chain_Extract_unprotected(). |
---|
957 | * |
---|
958 | * @warning This function will look at all registered chain iterators to |
---|
959 | * determine if an update is necessary. |
---|
960 | */ |
---|
961 | RTEMS_INLINE_ROUTINE void _Chain_Iterator_registry_update( |
---|
962 | Chain_Iterator_registry *the_registry, |
---|
963 | Chain_Node *the_node_to_extract |
---|
964 | ) |
---|
965 | { |
---|
966 | Chain_Node *iter_node; |
---|
967 | Chain_Node *iter_tail; |
---|
968 | |
---|
969 | iter_node = _Chain_Head( &the_registry->Iterators ); |
---|
970 | iter_tail = _Chain_Tail( &the_registry->Iterators ); |
---|
971 | |
---|
972 | while ( ( iter_node = _Chain_Next( iter_node ) ) != iter_tail ) { |
---|
973 | Chain_Iterator *iter; |
---|
974 | |
---|
975 | iter = (Chain_Iterator *) iter_node; |
---|
976 | |
---|
977 | if ( iter->position == the_node_to_extract ) { |
---|
978 | if ( iter->direction == CHAIN_ITERATOR_FORWARD ) { |
---|
979 | iter->position = _Chain_Previous( the_node_to_extract ); |
---|
980 | } else { |
---|
981 | iter->position = _Chain_Next( the_node_to_extract ); |
---|
982 | } |
---|
983 | } |
---|
984 | } |
---|
985 | } |
---|
986 | |
---|
987 | /** |
---|
988 | * @brief Initializes the chain iterator. |
---|
989 | * |
---|
990 | * In the following example nodes inserted during the iteration are visited in |
---|
991 | * case they are inserted after the current position in iteration order. |
---|
992 | * |
---|
993 | * @code |
---|
994 | * #include <rtems/score/chainimpl.h> |
---|
995 | * #include <rtems/score/isrlock.h> |
---|
996 | * |
---|
997 | * typedef struct { |
---|
998 | * Chain_Control Chain; |
---|
999 | * Chain_Iterator_registry Iterators; |
---|
1000 | * ISR_LOCK_MEMBER( Lock ) |
---|
1001 | * } Some_Control; |
---|
1002 | * |
---|
1003 | * void iterate( |
---|
1004 | * Some_Control *the_some, |
---|
1005 | * void ( *visitor )( Chain_Node * ) |
---|
1006 | * ) |
---|
1007 | * { |
---|
1008 | * ISR_lock_Context lock_context; |
---|
1009 | * Chain_Iterator iter; |
---|
1010 | * Chain_Node *node; |
---|
1011 | * const Chain_Node *end; |
---|
1012 | * |
---|
1013 | * end = _Chain_Immutable_tail( &the_some->Chain ); |
---|
1014 | * |
---|
1015 | * _ISR_lock_ISR_disable_and_acquire( &the_some->Lock, &lock_context ); |
---|
1016 | * |
---|
1017 | * _Chain_Iterator_initialize( |
---|
1018 | * &the_some->Chain, |
---|
1019 | * &the_some->Iterators, |
---|
1020 | * &iter, |
---|
1021 | * CHAIN_ITERATOR_FORWARD |
---|
1022 | * ); |
---|
1023 | * |
---|
1024 | * while ( ( node = _Chain_Iterator_next( &iter ) ) != end ) { |
---|
1025 | * _Chain_Iterator_set_position( &iter, node ); |
---|
1026 | * _ISR_lock_Release_and_ISR_enable( &the_some->Lock, &lock_context ); |
---|
1027 | * ( *visitor )( node ); |
---|
1028 | * _ISR_lock_ISR_disable_and_acquire( &the_some->Lock, &lock_context ); |
---|
1029 | * } |
---|
1030 | * |
---|
1031 | * _Chain_Iterator_destroy( &iter ); |
---|
1032 | * _ISR_lock_Release_and_ISR_enable( &the_some->Lock, &lock_context ); |
---|
1033 | * } |
---|
1034 | * @endcode |
---|
1035 | * |
---|
1036 | * @param the_chain The chain to iterate. |
---|
1037 | * @param the_registry The registry for the chain iterator. |
---|
1038 | * @param the_iterator The chain iterator to initialize. |
---|
1039 | * @param direction The iteration direction. |
---|
1040 | * |
---|
1041 | * @see _Chain_Iterator_next(), _Chain_Iterator_set_position() and |
---|
1042 | * Chain_Iterator_destroy(). |
---|
1043 | * |
---|
1044 | * @warning Think twice before you use a chain iterator. Its current |
---|
1045 | * implementation is unfit for use in performance relevant components, due to |
---|
1046 | * the linear time complexity in _Chain_Iterator_registry_update(). |
---|
1047 | */ |
---|
1048 | RTEMS_INLINE_ROUTINE void _Chain_Iterator_initialize( |
---|
1049 | Chain_Control *the_chain, |
---|
1050 | Chain_Iterator_registry *the_registry, |
---|
1051 | Chain_Iterator *the_iterator, |
---|
1052 | Chain_Iterator_direction direction |
---|
1053 | ) |
---|
1054 | { |
---|
1055 | _Chain_Initialize_node( &the_iterator->Registry_node ); |
---|
1056 | _Chain_Append_unprotected( |
---|
1057 | &the_registry->Iterators, |
---|
1058 | &the_iterator->Registry_node |
---|
1059 | ); |
---|
1060 | |
---|
1061 | the_iterator->direction = direction; |
---|
1062 | |
---|
1063 | if ( direction == CHAIN_ITERATOR_FORWARD ) { |
---|
1064 | the_iterator->position = _Chain_Head( the_chain ); |
---|
1065 | } else { |
---|
1066 | the_iterator->position = _Chain_Tail( the_chain ); |
---|
1067 | } |
---|
1068 | } |
---|
1069 | |
---|
1070 | /** |
---|
1071 | * @brief Returns the next node in the iterator direction. |
---|
1072 | * |
---|
1073 | * In case a next node exists, then the iterator should be updated via |
---|
1074 | * _Chain_Iterator_set_position() to continue with the next iteration step. |
---|
1075 | * |
---|
1076 | * @param the_iterator The chain iterator. |
---|
1077 | */ |
---|
1078 | RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Iterator_next( |
---|
1079 | const Chain_Iterator *the_iterator |
---|
1080 | ) |
---|
1081 | { |
---|
1082 | if ( the_iterator->direction == CHAIN_ITERATOR_FORWARD ) { |
---|
1083 | return _Chain_Next( the_iterator->position ); |
---|
1084 | } else { |
---|
1085 | return _Chain_Previous( the_iterator->position ); |
---|
1086 | } |
---|
1087 | } |
---|
1088 | |
---|
1089 | /** |
---|
1090 | * @brief Sets the iterator position. |
---|
1091 | * |
---|
1092 | * @param the_iterator The chain iterator. |
---|
1093 | * @param the_node The new iterator position. |
---|
1094 | */ |
---|
1095 | RTEMS_INLINE_ROUTINE void _Chain_Iterator_set_position( |
---|
1096 | Chain_Iterator *the_iterator, |
---|
1097 | Chain_Node *the_node |
---|
1098 | ) |
---|
1099 | { |
---|
1100 | the_iterator->position = the_node; |
---|
1101 | } |
---|
1102 | |
---|
1103 | /** |
---|
1104 | * @brief Destroys the iterator. |
---|
1105 | * |
---|
1106 | * Removes the iterator from its registry. |
---|
1107 | * |
---|
1108 | * @param the_iterator The chain iterator. |
---|
1109 | */ |
---|
1110 | RTEMS_INLINE_ROUTINE void _Chain_Iterator_destroy( |
---|
1111 | Chain_Iterator *the_iterator |
---|
1112 | ) |
---|
1113 | { |
---|
1114 | _Chain_Extract_unprotected( &the_iterator->Registry_node ); |
---|
1115 | } |
---|
1116 | |
---|
1117 | /** @} */ |
---|
1118 | |
---|
1119 | #ifdef __cplusplus |
---|
1120 | } |
---|
1121 | #endif |
---|
1122 | |
---|
1123 | #endif |
---|
1124 | /* end of include file */ |
---|