1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT LIBRARY COMPONENTS                          --
4--                                                                          --
5--                 ADA.CONTAINERS.HASH_TABLES.GENERIC_KEYS                  --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 2004-2019, 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 depend on keys.
32
33generic
34   with package HT_Types is
35     new Generic_Hash_Table_Types (<>);
36
37   use HT_Types, HT_Types.Implementation;
38
39   with function Next (Node : Node_Access) return Node_Access;
40
41   with procedure Set_Next
42     (Node : Node_Access;
43      Next : Node_Access);
44
45   type Key_Type (<>) is limited private;
46
47   with function Hash (Key : Key_Type) return Hash_Type;
48
49   with function Equivalent_Keys
50     (Key  : Key_Type;
51      Node : Node_Access) return Boolean;
52
53package Ada.Containers.Hash_Tables.Generic_Keys is
54   pragma Preelaborate;
55
56   function Index
57     (HT  : Hash_Table_Type;
58      Key : Key_Type) return Hash_Type;
59   pragma Inline (Index);
60   --  Returns the bucket number (array index value) for the given key
61
62   function Checked_Index
63     (HT  : aliased in out Hash_Table_Type;
64      Key : Key_Type) return Hash_Type;
65   pragma Inline (Checked_Index);
66   --  Calls Index, but also locks and unlocks the container, per AI05-0022, in
67   --  order to detect element tampering by the generic actual Hash function.
68
69   function Checked_Equivalent_Keys
70     (HT   : aliased in out Hash_Table_Type;
71      Key  : Key_Type;
72      Node : Node_Access) return Boolean;
73   --  Calls Equivalent_Keys, but locks and unlocks the container, per
74   --  AI05-0022, in order to detect element tampering by that generic actual.
75
76   procedure Delete_Key_Sans_Free
77     (HT  : in out Hash_Table_Type;
78      Key : Key_Type;
79      X   : out Node_Access);
80   --  Removes the node (if any) with the given key from the hash table,
81   --  without deallocating it. Program_Error is raised if the hash
82   --  table is busy.
83
84   function Find
85     (HT  : aliased in out Hash_Table_Type;
86      Key : Key_Type) return Node_Access;
87   --  Returns the node (if any) corresponding to the given key
88
89   generic
90      with function New_Node (Next : Node_Access) return Node_Access;
91   procedure Generic_Conditional_Insert
92     (HT       : in out Hash_Table_Type;
93      Key      : Key_Type;
94      Node     : out Node_Access;
95      Inserted : out Boolean);
96   --  Attempts to insert a new node with the given key into the hash table.
97   --  If a node with that key already exists in the table, then that node
98   --  is returned and Inserted returns False. Otherwise New_Node is called
99   --  to allocate a new node, and Inserted returns True. Program_Error is
100   --  raised if the hash table is busy.
101
102   generic
103      with function Hash (Node : Node_Access) return Hash_Type;
104      with procedure Assign (Node : Node_Access; Key : Key_Type);
105   procedure Generic_Replace_Element
106     (HT   : in out Hash_Table_Type;
107      Node : Node_Access;
108      Key  : Key_Type);
109   --  Assigns Key to Node, possibly changing its equivalence class. If Node
110   --  is in the same equivalence class as Key (that is, it's already in the
111   --  bucket implied by Key), then if the hash table is locked then
112   --  Program_Error is raised; otherwise Assign is called to assign Key to
113   --  Node. If Node is in a different bucket from Key, then Program_Error is
114   --  raised if the hash table is busy. Otherwise it Assigns Key to Node and
115   --  moves the Node from its current bucket to the bucket implied by Key.
116   --  Note that it is never proper to assign to Node a key value already
117   --  in the map, and so if Key is equivalent to some other node then
118   --  Program_Error is raised.
119
120end Ada.Containers.Hash_Tables.Generic_Keys;
121