1 | /** |
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2 | * @file chain.h |
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3 | * |
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4 | * This include file contains all the constants and structures associated |
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5 | * with the Doubly-Linked Chain Handler. |
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6 | */ |
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7 | |
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8 | /* |
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9 | * COPYRIGHT (c) 1989-2004. |
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10 | * On-Line Applications Research Corporation (OAR). |
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11 | * |
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12 | * The license and distribution terms for this file may be |
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13 | * found in the file LICENSE in this distribution or at |
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14 | * http://www.rtems.com/license/LICENSE. |
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15 | * |
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16 | * $Id$ |
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17 | */ |
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18 | |
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19 | #ifndef __RTEMS_CHAIN_h |
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20 | #define __RTEMS_CHAIN_h |
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21 | |
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22 | /** |
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23 | * @defgroup ScoreChain Chain Handler |
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24 | * |
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25 | * The Chain Handler contains XXX |
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26 | */ |
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27 | /**@{*/ |
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28 | |
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29 | #ifdef __cplusplus |
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30 | extern "C" { |
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31 | #endif |
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32 | |
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33 | #include <rtems/score/address.h> |
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34 | |
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35 | /** |
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36 | * @typedef Chain_Node |
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37 | * |
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38 | * This type definition promotes the name for the Chain Node used by |
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39 | * all RTEMS code. It is a separate type definition because a forward |
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40 | * reference is required to define it. |
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41 | */ |
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42 | typedef struct Chain_Node_struct Chain_Node; |
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43 | |
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44 | /** |
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45 | * @struct Chain_Node_struct |
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46 | * |
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47 | * This is used to manage each element (node) which is placed |
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48 | * on a chain. |
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49 | * |
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50 | * @note Typically, a more complicated structure will use the |
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51 | * chain package. The more complicated structure will |
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52 | * include a chain node as the first element in its |
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53 | * control structure. It will then call the chain package |
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54 | * with a pointer to that node element. The node pointer |
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55 | * and the higher level structure start at the same address |
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56 | * so the user can cast the pointers back and forth. |
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57 | * |
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58 | */ |
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59 | struct Chain_Node_struct { |
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60 | /** This points to the node after to this one on this chain. */ |
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61 | Chain_Node *next; |
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62 | /** This points to the node immediate prior to this one on this chain. */ |
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63 | Chain_Node *previous; |
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64 | }; |
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65 | |
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66 | /** |
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67 | * @struct Chain_Control |
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68 | * |
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69 | * This is used to manage a chain. A chain consists of a doubly |
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70 | * linked list of zero or more nodes. |
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71 | * |
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72 | * @note This implementation does not require special checks for |
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73 | * manipulating the first and last elements on the chain. |
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74 | * To accomplish this the @a Chain_Control structure is |
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75 | * treated as two overlapping @ref Chain_Node structures. |
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76 | * The permanent head of the chain overlays a node structure on the |
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77 | * @a first and @a permanent_null fields. The permanent tail |
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78 | * of the chain overlays a node structure on the |
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79 | * @a permanent_null and @a last elements of the structure. |
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80 | * |
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81 | */ |
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82 | typedef struct { |
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83 | /** This points to the first node on this chain. */ |
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84 | Chain_Node *first; |
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85 | /** This field is always 0. */ |
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86 | Chain_Node *permanent_null; |
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87 | /** This points to the last node on this chain. */ |
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88 | Chain_Node *last; |
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89 | } Chain_Control; |
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90 | |
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91 | /** |
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92 | * @brief Initialize a Chain Header |
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93 | * |
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94 | * This routine initializes @a the_chain structure to manage the |
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95 | * contiguous array of @a number_nodes nodes which starts at |
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96 | * @a starting_address. Each node is of @a node_size bytes. |
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97 | * |
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98 | * @param the_chain (in) specifies the chain to initialize |
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99 | * @param starting_address (in) is the starting address of the array |
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100 | * of elements |
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101 | * @param number_nodes (in) is the numebr of nodes that will be in the chain |
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102 | * @param node_size (in) is the size of each node |
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103 | */ |
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104 | void _Chain_Initialize( |
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105 | Chain_Control *the_chain, |
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106 | void *starting_address, |
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107 | unsigned32 number_nodes, |
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108 | unsigned32 node_size |
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109 | ); |
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110 | |
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111 | #ifndef RTEMS_INLINES |
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112 | /** |
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113 | * @brief Get the first node (do not disable interrupts) |
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114 | * |
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115 | * This method attempts to obtain the first node from \a the_chain. |
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116 | * |
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117 | * @param the_chain (in) points to the chain to operate upon |
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118 | * @return If successful, a chain node is returned. Otherwise, NULL |
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119 | * is returned. |
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120 | */ |
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121 | Chain_Node *_Chain_Get_first_unprotected( |
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122 | Chain_Control *the_chain |
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123 | ); |
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124 | #endif |
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125 | |
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126 | /** |
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127 | * @brief Extract the specified node from a chain |
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128 | * |
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129 | * This routine extracts \a the_node from the chain on which it resides. |
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130 | * It disables interrupts to insure the atomicity of the |
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131 | * extract operation. |
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132 | * |
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133 | * @arg the_node specifies the node to extract |
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134 | */ |
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135 | void _Chain_Extract( |
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136 | Chain_Node *the_node |
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137 | ); |
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138 | |
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139 | /** |
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140 | * @brief Obtain the first node on a chain |
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141 | * |
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142 | * This function removes the first node from \a the_chain and returns |
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143 | * a pointer to that node. If \a the_chain is empty, then NULL is returned. |
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144 | * |
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145 | * @note It disables interrupts to insure the atomicity of the |
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146 | * get operation. |
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147 | */ |
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148 | Chain_Node *_Chain_Get( |
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149 | Chain_Control *the_chain |
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150 | ); |
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151 | |
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152 | /** |
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153 | * @brief Insert a node on a chain |
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154 | * |
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155 | * This routine inserts \a the_node on a chain immediately following |
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156 | * \a after_node. |
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157 | * |
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158 | * @note It disables interrupts to insure the atomicity |
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159 | * of the extract operation. |
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160 | */ |
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161 | void _Chain_Insert( |
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162 | Chain_Node *after_node, |
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163 | Chain_Node *the_node |
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164 | ); |
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165 | |
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166 | /** |
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167 | * @brief Append a node on the end of a chain |
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168 | * |
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169 | * This routine appends \a the_node onto the end of \a the_chain. |
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170 | * |
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171 | * @note It disables interrupts to insure the atomicity of the |
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172 | * append operation. |
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173 | */ |
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174 | void _Chain_Append( |
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175 | Chain_Control *the_chain, |
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176 | Chain_Node *the_node |
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177 | ); |
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178 | |
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179 | #ifndef __RTEMS_APPLICATION__ |
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180 | #include <rtems/score/chain.inl> |
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181 | #endif |
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182 | |
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183 | #ifdef __cplusplus |
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184 | } |
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185 | #endif |
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186 | |
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187 | /**@}*/ |
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188 | |
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189 | #endif |
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190 | /* end of include file */ |
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