File : a-chtgop.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT LIBRARY COMPONENTS --
4 -- --
5 -- ADA.CONTAINERS.HASH_TABLES.GENERIC_OPERATIONS --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 2004-2015, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
26 -- --
27 -- This unit was originally developed by Matthew J Heaney. --
28 ------------------------------------------------------------------------------
29
30 -- Hash_Table_Type is used to implement hashed containers. This package
31 -- declares hash-table operations that do not depend on keys.
32
33 with Ada.Streams;
34
35 generic
36
37 with package HT_Types is
38 new Generic_Hash_Table_Types (<>);
39
40 use HT_Types, HT_Types.Implementation;
41
42 with function Hash_Node (Node : Node_Access) return Hash_Type;
43
44 with function Next (Node : Node_Access) return Node_Access;
45
46 with procedure Set_Next
47 (Node : Node_Access;
48 Next : Node_Access);
49
50 with function Copy_Node (Source : Node_Access) return Node_Access;
51
52 with procedure Free (X : in out Node_Access);
53
54 package Ada.Containers.Hash_Tables.Generic_Operations is
55 pragma Preelaborate;
56
57 procedure Free_Hash_Table (Buckets : in out Buckets_Access);
58 -- First frees the nodes in all non-null buckets of Buckets, and then frees
59 -- the Buckets array itself.
60
61 function Index
62 (Buckets : Buckets_Type;
63 Node : Node_Access) return Hash_Type;
64 pragma Inline (Index);
65 -- Uses the hash value of Node to compute its Buckets array index
66
67 function Index
68 (Hash_Table : Hash_Table_Type;
69 Node : Node_Access) return Hash_Type;
70 pragma Inline (Index);
71 -- Uses the hash value of Node to compute its Hash_Table buckets array
72 -- index.
73
74 function Checked_Index
75 (Hash_Table : aliased in out Hash_Table_Type;
76 Buckets : Buckets_Type;
77 Node : Node_Access) return Hash_Type;
78 -- Calls Index, but also locks and unlocks the container, per AI05-0022, in
79 -- order to detect element tampering by the generic actual Hash function.
80
81 function Checked_Index
82 (Hash_Table : aliased in out Hash_Table_Type;
83 Node : Node_Access) return Hash_Type;
84 -- Calls Checked_Index using Hash_Table's buckets array.
85
86 procedure Adjust (HT : in out Hash_Table_Type);
87 -- Used to implement controlled Adjust. It is assumed that HT has the value
88 -- of the bit-wise copy that immediately follows controlled Finalize.
89 -- Adjust first allocates a new buckets array for HT (having the same
90 -- length as the source), and then allocates a copy of each node of source.
91
92 procedure Finalize (HT : in out Hash_Table_Type);
93 -- Used to implement controlled Finalize. It first calls Clear to
94 -- deallocate any remaining nodes, and then deallocates the buckets array.
95
96 generic
97 with function Find
98 (HT : Hash_Table_Type;
99 Key : Node_Access) return Boolean;
100 function Generic_Equal
101 (L, R : Hash_Table_Type) return Boolean;
102 -- Used to implement hashed container equality. For each node in hash table
103 -- L, it calls Find to search for an equivalent item in hash table R. If
104 -- Find returns False for any node then Generic_Equal terminates
105 -- immediately and returns False. Otherwise if Find returns True for every
106 -- node then Generic_Equal returns True.
107
108 procedure Clear (HT : in out Hash_Table_Type);
109 -- Deallocates each node in hash table HT. (Note that it only deallocates
110 -- the nodes, not the buckets array.) Program_Error is raised if the hash
111 -- table is busy.
112
113 procedure Move (Target, Source : in out Hash_Table_Type);
114 -- Moves (not copies) the buckets array and nodes from Source to
115 -- Target. Program_Error is raised if Source is busy. The Target is first
116 -- cleared to deallocate its nodes (implying that Program_Error is also
117 -- raised if Target is busy). Source is empty following the move.
118
119 function Capacity (HT : Hash_Table_Type) return Count_Type;
120 -- Returns the length of the buckets array
121
122 procedure Reserve_Capacity
123 (HT : in out Hash_Table_Type;
124 N : Count_Type);
125 -- If N is greater than the current capacity, then it expands the buckets
126 -- array to at least the value N. If N is less than the current capacity,
127 -- then it contracts the buckets array. In either case existing nodes are
128 -- rehashed onto the new buckets array, and the old buckets array is
129 -- deallocated. Program_Error is raised if the hash table is busy.
130
131 procedure Delete_Node_At_Index
132 (HT : in out Hash_Table_Type;
133 Indx : Hash_Type;
134 X : in out Node_Access);
135 -- Delete a node whose bucket position is known. Used to remove a node
136 -- whose element has been modified through a key_preserving reference.
137 -- We cannot use the value of the element precisely because the current
138 -- value does not correspond to the hash code that determines the bucket.
139
140 procedure Delete_Node_Sans_Free
141 (HT : in out Hash_Table_Type;
142 X : Node_Access);
143 -- Removes node X from the hash table without deallocating the node
144
145 function First (HT : Hash_Table_Type) return Node_Access;
146 -- Returns the head of the list in the first (lowest-index) non-empty
147 -- bucket.
148
149 function Next
150 (HT : aliased in out Hash_Table_Type;
151 Node : Node_Access) return Node_Access;
152 -- Returns the node that immediately follows Node. This corresponds to
153 -- either the next node in the same bucket, or (if Node is the last node in
154 -- its bucket) the head of the list in the first non-empty bucket that
155 -- follows.
156
157 generic
158 with procedure Process (Node : Node_Access);
159 procedure Generic_Iteration (HT : Hash_Table_Type);
160 -- Calls Process for each node in hash table HT
161
162 generic
163 use Ada.Streams;
164 with procedure Write
165 (Stream : not null access Root_Stream_Type'Class;
166 Node : Node_Access);
167 procedure Generic_Write
168 (Stream : not null access Root_Stream_Type'Class;
169 HT : Hash_Table_Type);
170 -- Used to implement the streaming attribute for hashed containers. It
171 -- calls Write for each node to write its value into Stream.
172
173 generic
174 use Ada.Streams;
175 with function New_Node
176 (Stream : not null access Root_Stream_Type'Class)
177 return Node_Access;
178 procedure Generic_Read
179 (Stream : not null access Root_Stream_Type'Class;
180 HT : out Hash_Table_Type);
181 -- Used to implement the streaming attribute for hashed containers. It
182 -- first clears hash table HT, then populates the hash table by calling
183 -- New_Node for each item in Stream.
184
185 function New_Buckets (Length : Hash_Type) return Buckets_Access;
186 pragma Inline (New_Buckets);
187 -- Allocate a new Buckets_Type array with bounds 0 .. Length - 1
188
189 procedure Free_Buckets (Buckets : in out Buckets_Access);
190 pragma Inline (Free_Buckets);
191 -- Unchecked_Deallocate Buckets
192
193 -- Note: New_Buckets and Free_Buckets are needed because Buckets_Access has
194 -- an empty pool.
195
196 end Ada.Containers.Hash_Tables.Generic_Operations;