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1 ------------------------------------------------------------------------------
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2 -- --
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3 -- GNAT LIBRARY COMPONENTS --
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4 -- --
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5 -- ADA.CONTAINERS.HASH_TABLES.GENERIC_OPERATIONS --
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6 -- --
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7 -- S p e c --
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8 -- --
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145
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9 -- Copyright (C) 2004-2019, Free Software Foundation, Inc. --
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111
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10 -- --
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11 -- GNAT is free software; you can redistribute it and/or modify it under --
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12 -- terms of the GNU General Public License as published by the Free Soft- --
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13 -- ware Foundation; either version 3, or (at your option) any later ver- --
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14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
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17 -- --
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18 -- As a special exception under Section 7 of GPL version 3, you are granted --
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19 -- additional permissions described in the GCC Runtime Library Exception, --
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20 -- version 3.1, as published by the Free Software Foundation. --
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21 -- --
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22 -- You should have received a copy of the GNU General Public License and --
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23 -- a copy of the GCC Runtime Library Exception along with this program; --
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24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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25 -- <http://www.gnu.org/licenses/>. --
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26 -- --
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27 -- This unit was originally developed by Matthew J Heaney. --
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28 ------------------------------------------------------------------------------
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29
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30 -- Hash_Table_Type is used to implement hashed containers. This package
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31 -- declares hash-table operations that do not depend on keys.
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32
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33 with Ada.Streams;
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34
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35 generic
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36
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37 with package HT_Types is
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38 new Generic_Hash_Table_Types (<>);
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39
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40 use HT_Types, HT_Types.Implementation;
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41
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42 with function Hash_Node (Node : Node_Access) return Hash_Type;
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43
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44 with function Next (Node : Node_Access) return Node_Access;
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45
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46 with procedure Set_Next
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47 (Node : Node_Access;
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48 Next : Node_Access);
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49
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50 with function Copy_Node (Source : Node_Access) return Node_Access;
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51
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52 with procedure Free (X : in out Node_Access);
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53
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54 package Ada.Containers.Hash_Tables.Generic_Operations is
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55 pragma Preelaborate;
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56
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57 procedure Free_Hash_Table (Buckets : in out Buckets_Access);
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58 -- First frees the nodes in all non-null buckets of Buckets, and then frees
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59 -- the Buckets array itself.
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60
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61 function Index
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62 (Buckets : Buckets_Type;
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63 Node : Node_Access) return Hash_Type;
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64 pragma Inline (Index);
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65 -- Uses the hash value of Node to compute its Buckets array index
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66
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67 function Index
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68 (Hash_Table : Hash_Table_Type;
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69 Node : Node_Access) return Hash_Type;
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70 pragma Inline (Index);
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71 -- Uses the hash value of Node to compute its Hash_Table buckets array
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72 -- index.
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73
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74 function Checked_Index
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75 (Hash_Table : aliased in out Hash_Table_Type;
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76 Buckets : Buckets_Type;
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77 Node : Node_Access) return Hash_Type;
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78 -- Calls Index, but also locks and unlocks the container, per AI05-0022, in
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79 -- order to detect element tampering by the generic actual Hash function.
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80
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81 function Checked_Index
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82 (Hash_Table : aliased in out Hash_Table_Type;
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83 Node : Node_Access) return Hash_Type;
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84 -- Calls Checked_Index using Hash_Table's buckets array.
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85
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86 procedure Adjust (HT : in out Hash_Table_Type);
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87 -- Used to implement controlled Adjust. It is assumed that HT has the value
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88 -- of the bit-wise copy that immediately follows controlled Finalize.
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89 -- Adjust first allocates a new buckets array for HT (having the same
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90 -- length as the source), and then allocates a copy of each node of source.
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91
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92 procedure Finalize (HT : in out Hash_Table_Type);
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93 -- Used to implement controlled Finalize. It first calls Clear to
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94 -- deallocate any remaining nodes, and then deallocates the buckets array.
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95
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96 generic
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97 with function Find
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98 (HT : Hash_Table_Type;
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99 Key : Node_Access) return Boolean;
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100 function Generic_Equal
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101 (L, R : Hash_Table_Type) return Boolean;
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102 -- Used to implement hashed container equality. For each node in hash table
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103 -- L, it calls Find to search for an equivalent item in hash table R. If
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104 -- Find returns False for any node then Generic_Equal terminates
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105 -- immediately and returns False. Otherwise if Find returns True for every
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106 -- node then Generic_Equal returns True.
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107
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108 procedure Clear (HT : in out Hash_Table_Type);
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109 -- Deallocates each node in hash table HT. (Note that it only deallocates
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110 -- the nodes, not the buckets array. Also note that for bounded containers,
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111 -- the buckets array is not dynamically allocated). Program_Error is raised
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112 -- if the hash table is busy.
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111
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113
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114 procedure Move (Target, Source : in out Hash_Table_Type);
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115 -- Moves (not copies) the buckets array and nodes from Source to
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116 -- Target. Program_Error is raised if Source is busy. The Target is first
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117 -- cleared to deallocate its nodes (implying that Program_Error is also
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118 -- raised if Target is busy). Source is empty following the move.
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119
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120 function Capacity (HT : Hash_Table_Type) return Count_Type;
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121 -- Returns the length of the buckets array
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122
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123 procedure Reserve_Capacity
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124 (HT : in out Hash_Table_Type;
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125 N : Count_Type);
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126 -- If N is greater than the current capacity, then it expands the buckets
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127 -- array to at least the value N. If N is less than the current capacity,
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128 -- then it contracts the buckets array. In either case existing nodes are
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129 -- rehashed onto the new buckets array, and the old buckets array is
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130 -- deallocated. Program_Error is raised if the hash table is busy.
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131
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132 procedure Delete_Node_At_Index
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133 (HT : in out Hash_Table_Type;
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134 Indx : Hash_Type;
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135 X : in out Node_Access);
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136 -- Delete a node whose bucket position is known. Used to remove a node
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137 -- whose element has been modified through a key_preserving reference.
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138 -- We cannot use the value of the element precisely because the current
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139 -- value does not correspond to the hash code that determines the bucket.
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140
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141 procedure Delete_Node_Sans_Free
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142 (HT : in out Hash_Table_Type;
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143 X : Node_Access);
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144 -- Removes node X from the hash table without deallocating the node
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145
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146 function First
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147 (HT : Hash_Table_Type) return Node_Access;
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148 function First
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149 (HT : Hash_Table_Type;
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150 Position : out Hash_Type) return Node_Access;
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151 -- Returns the head of the list in the first (lowest-index) non-empty
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152 -- bucket. Position will be the index of the bucket of the first node.
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153 -- It is provided so that clients can implement efficient iterators.
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154
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155 function Next
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156 (HT : aliased in out Hash_Table_Type;
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157 Node : Node_Access) return Node_Access;
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158 function Next
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159 (HT : aliased in out Hash_Table_Type;
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160 Node : Node_Access;
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161 Position : in out Hash_Type) return Node_Access;
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162 -- Returns the node that immediately follows Node. This corresponds to
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163 -- either the next node in the same bucket, or (if Node is the last node in
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164 -- its bucket) the head of the list in the first non-empty bucket that
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165 -- follows.
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166 --
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167 -- If Node_Position is supplied, then it will be used as a starting point
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168 -- for iteration (Node_Position must be the index of Node's buckets). If it
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169 -- is not supplied, it will be recomputed. It is provided so that clients
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170 -- can implement efficient iterators.
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171
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172 generic
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173 with procedure Process (Node : Node_Access; Position : Hash_Type);
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174 procedure Generic_Iteration_With_Position (HT : Hash_Table_Type);
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175 -- Calls Process for each node in hash table HT
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176
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177 generic
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178 with procedure Process (Node : Node_Access);
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179 procedure Generic_Iteration (HT : Hash_Table_Type);
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180 -- Calls Process for each node in hash table HT
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181
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182 generic
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183 use Ada.Streams;
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184 with procedure Write
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185 (Stream : not null access Root_Stream_Type'Class;
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186 Node : Node_Access);
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187 procedure Generic_Write
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188 (Stream : not null access Root_Stream_Type'Class;
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189 HT : Hash_Table_Type);
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190 -- Used to implement the streaming attribute for hashed containers. It
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191 -- calls Write for each node to write its value into Stream.
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192
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193 generic
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194 use Ada.Streams;
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195 with function New_Node
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196 (Stream : not null access Root_Stream_Type'Class)
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197 return Node_Access;
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198 procedure Generic_Read
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199 (Stream : not null access Root_Stream_Type'Class;
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200 HT : out Hash_Table_Type);
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201 -- Used to implement the streaming attribute for hashed containers. It
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202 -- first clears hash table HT, then populates the hash table by calling
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203 -- New_Node for each item in Stream.
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204
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205 function New_Buckets (Length : Hash_Type) return Buckets_Access;
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206 pragma Inline (New_Buckets);
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207 -- Allocate a new Buckets_Type array with bounds 0 .. Length - 1
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208
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209 procedure Free_Buckets (Buckets : in out Buckets_Access);
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210 pragma Inline (Free_Buckets);
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211 -- Unchecked_Deallocate Buckets
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212
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213 -- Note: New_Buckets and Free_Buckets are needed because Buckets_Access has
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214 -- an empty pool.
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215
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216 end Ada.Containers.Hash_Tables.Generic_Operations;
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