1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT LIBRARY COMPONENTS                          --
4--                                                                          --
5--              ADA.CONTAINERS.HASH_TABLES.GENERIC_OPERATIONS               --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 2004-2009, 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-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
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
33with Ada.Streams;
34
35generic
36
37   with package HT_Types is
38     new Generic_Hash_Table_Types (<>);
39
40   use HT_Types;
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
54package 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   procedure Adjust (HT : in out Hash_Table_Type);
75   --  Used to implement controlled Adjust. It is assumed that HT has the value
76   --  of the bit-wise copy that immediately follows controlled Finalize.
77   --  Adjust first allocates a new buckets array for HT (having the same
78   --  length as the source), and then allocates a copy of each node of source.
79
80   procedure Finalize (HT : in out Hash_Table_Type);
81   --  Used to implement controlled Finalize. It first calls Clear to
82   --  deallocate any remaining nodes, and then deallocates the buckets array.
83
84   generic
85      with function Find
86        (HT  : Hash_Table_Type;
87         Key : Node_Access) return Boolean;
88   function Generic_Equal
89     (L, R : Hash_Table_Type) return Boolean;
90   --  Used to implement hashed container equality. For each node in hash table
91   --  L, it calls Find to search for an equivalent item in hash table R. If
92   --  Find returns False for any node then Generic_Equal terminates
93   --  immediately and returns False. Otherwise if Find returns True for every
94   --  node then Generic_Equal returns True.
95
96   procedure Clear (HT : in out Hash_Table_Type);
97   --  Deallocates each node in hash table HT. (Note that it only deallocates
98   --  the nodes, not the buckets array.)  Program_Error is raised if the hash
99   --  table is busy.
100
101   procedure Move (Target, Source : in out Hash_Table_Type);
102   --  Moves (not copies) the buckets array and nodes from Source to
103   --  Target. Program_Error is raised if Source is busy. The Target is first
104   --  cleared to deallocate its nodes (implying that Program_Error is also
105   --  raised if Target is busy). Source is empty following the move.
106
107   function Capacity (HT : Hash_Table_Type) return Count_Type;
108   --  Returns the length of the buckets array
109
110   procedure Reserve_Capacity
111     (HT : in out Hash_Table_Type;
112      N  : Count_Type);
113   --  If N is greater than the current capacity, then it expands the buckets
114   --  array to at least the value N. If N is less than the current capacity,
115   --  then it contracts the buckets array. In either case existing nodes are
116   --  rehashed onto the new buckets array, and the old buckets array is
117   --  deallocated. Program_Error is raised if the hash table is busy.
118
119   procedure Delete_Node_Sans_Free
120     (HT : in out Hash_Table_Type;
121      X  : Node_Access);
122   --  Removes node X from the hash table without deallocating the node
123
124   function First (HT : Hash_Table_Type) return Node_Access;
125   --  Returns the head of the list in the first (lowest-index) non-empty
126   --  bucket.
127
128   function Next
129     (HT   : Hash_Table_Type;
130      Node : Node_Access) return Node_Access;
131   --  Returns the node that immediately follows Node. This corresponds to
132   --  either the next node in the same bucket, or (if Node is the last node in
133   --  its bucket) the head of the list in the first non-empty bucket that
134   --  follows.
135
136   generic
137      with procedure Process (Node : Node_Access);
138   procedure Generic_Iteration (HT : Hash_Table_Type);
139   --  Calls Process for each node in hash table HT
140
141   generic
142      use Ada.Streams;
143      with procedure Write
144        (Stream : not null access Root_Stream_Type'Class;
145         Node   : Node_Access);
146   procedure Generic_Write
147     (Stream : not null access Root_Stream_Type'Class;
148      HT     : Hash_Table_Type);
149   --  Used to implement the streaming attribute for hashed containers. It
150   --  calls Write for each node to write its value into Stream.
151
152   generic
153      use Ada.Streams;
154      with function New_Node (Stream : not null access Root_Stream_Type'Class)
155         return Node_Access;
156   procedure Generic_Read
157     (Stream : not null access Root_Stream_Type'Class;
158      HT     : out Hash_Table_Type);
159   --  Used to implement the streaming attribute for hashed containers. It
160   --  first clears hash table HT, then populates the hash table by calling
161   --  New_Node for each item in Stream.
162
163   function New_Buckets (Length : Hash_Type) return Buckets_Access;
164   pragma Inline (New_Buckets);
165   --  Allocate a new Buckets_Type array with bounds 0..Length-1
166
167   procedure Free_Buckets (Buckets : in out Buckets_Access);
168   pragma Inline (Free_Buckets);
169   --  Unchecked_Deallocate Buckets
170
171   --  Note: New_Buckets and Free_Buckets are needed because Buckets_Access has
172   --  an empty pool.
173
174end Ada.Containers.Hash_Tables.Generic_Operations;
175