1 ------------------------------------------------------------------------------
3 -- GNAT LIBRARY COMPONENTS --
5 -- A D A . C O N T A I N E R S . H A S H E D _ M A P S --
9 -- Copyright (C) 2004-2011, Free Software Foundation, Inc. --
11 -- This specification is derived from the Ada Reference Manual for use with --
12 -- GNAT. The copyright notice above, and the license provisions that follow --
13 -- apply solely to the contents of the part following the private keyword. --
15 -- GNAT is free software; you can redistribute it and/or modify it under --
16 -- terms of the GNU General Public License as published by the Free Soft- --
17 -- ware Foundation; either version 3, or (at your option) any later ver- --
18 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
19 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
20 -- or FITNESS FOR A PARTICULAR PURPOSE. --
22 -- As a special exception under Section 7 of GPL version 3, you are granted --
23 -- additional permissions described in the GCC Runtime Library Exception, --
24 -- version 3.1, as published by the Free Software Foundation. --
26 -- You should have received a copy of the GNU General Public License and --
27 -- a copy of the GCC Runtime Library Exception along with this program; --
28 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
29 -- <http://www.gnu.org/licenses/>. --
31 -- This unit was originally developed by Matthew J Heaney. --
32 ------------------------------------------------------------------------------
34 private with Ada
.Containers
.Hash_Tables
;
35 private with Ada
.Finalization
;
37 with Ada
.Streams
; use Ada
.Streams
;
38 with Ada
.Iterator_Interfaces
;
41 type Key_Type
is private;
42 type Element_Type
is private;
44 with function Hash
(Key
: Key_Type
) return Hash_Type
;
45 with function Equivalent_Keys
(Left
, Right
: Key_Type
) return Boolean;
46 with function "=" (Left
, Right
: Element_Type
) return Boolean is <>;
48 package Ada
.Containers
.Hashed_Maps
is
52 type Map
is tagged private
54 Constant_Indexing
=> Constant_Reference
,
55 Variable_Indexing
=> Reference
,
56 Default_Iterator
=> Iterate
,
57 Iterator_Element
=> Element_Type
;
59 pragma Preelaborable_Initialization
(Map
);
61 type Cursor
is private;
62 pragma Preelaborable_Initialization
(Cursor
);
65 (Stream
: not null access Root_Stream_Type
'Class;
68 for Cursor
'Read use Read
;
71 (Stream
: not null access Root_Stream_Type
'Class;
74 for Cursor
'Write use Write
;
76 Empty_Map
: constant Map
;
77 -- Map objects declared without an initialization expression are
78 -- initialized to the value Empty_Map.
80 No_Element
: constant Cursor
;
81 -- Cursor objects declared without an initialization expression are
82 -- initialized to the value No_Element.
84 function Has_Element
(Position
: Cursor
) return Boolean;
85 -- Equivalent to Position /= No_Element
87 package Map_Iterator_Interfaces
is new
88 Ada
.Iterator_Interfaces
(Cursor
, Has_Element
);
90 function "=" (Left
, Right
: Map
) return Boolean;
91 -- For each key/element pair in Left, equality attempts to find the key in
92 -- Right; if a search fails the equality returns False. The search works by
93 -- calling Hash to find the bucket in the Right map that corresponds to the
94 -- Left key. If bucket is non-empty, then equality calls Equivalent_Keys
95 -- to compare the key (in Left) to the key of each node in the bucket (in
96 -- Right); if the keys are equivalent, then the equality test for this
97 -- key/element pair (in Left) completes by calling the element equality
98 -- operator to compare the element (in Left) to the element of the node
99 -- (in Right) whose key matched.
101 function Capacity
(Container
: Map
) return Count_Type
;
102 -- Returns the current capacity of the map. Capacity is the maximum length
103 -- before which rehashing in guaranteed not to occur.
105 procedure Reserve_Capacity
(Container
: in out Map
; Capacity
: Count_Type
);
106 -- Adjusts the current capacity, by allocating a new buckets array. If the
107 -- requested capacity is less than the current capacity, then the capacity
108 -- is contracted (to a value not less than the current length). If the
109 -- requested capacity is greater than the current capacity, then the
110 -- capacity is expanded (to a value not less than what is requested). In
111 -- either case, the nodes are rehashed from the old buckets array onto the
112 -- new buckets array (Hash is called once for each existing key in order to
113 -- compute the new index), and then the old buckets array is deallocated.
115 function Length
(Container
: Map
) return Count_Type
;
116 -- Returns the number of items in the map
118 function Is_Empty
(Container
: Map
) return Boolean;
119 -- Equivalent to Length (Container) = 0
121 procedure Clear
(Container
: in out Map
);
122 -- Removes all of the items from the map
124 function Key
(Position
: Cursor
) return Key_Type
;
125 -- Returns the key of the node designated by the cursor
127 function Element
(Position
: Cursor
) return Element_Type
;
128 -- Returns the element of the node designated by the cursor
130 procedure Replace_Element
131 (Container
: in out Map
;
133 New_Item
: Element_Type
);
134 -- Assigns the value New_Item to the element designated by the cursor
136 procedure Query_Element
138 Process
: not null access
139 procedure (Key
: Key_Type
; Element
: Element_Type
));
140 -- Calls Process with the key and element (both having only a constant
141 -- view) of the node designed by the cursor.
143 procedure Update_Element
144 (Container
: in out Map
;
146 Process
: not null access
147 procedure (Key
: Key_Type
; Element
: in out Element_Type
));
148 -- Calls Process with the key (with only a constant view) and element (with
149 -- a variable view) of the node designed by the cursor.
151 procedure Assign
(Target
: in out Map
; Source
: Map
);
153 function Copy
(Source
: Map
; Capacity
: Count_Type
:= 0) return Map
;
155 procedure Move
(Target
: in out Map
; Source
: in out Map
);
156 -- Clears Target (if it's not empty), and then moves (not copies) the
157 -- buckets array and nodes from Source to Target.
160 (Container
: in out Map
;
162 New_Item
: Element_Type
;
163 Position
: out Cursor
;
164 Inserted
: out Boolean);
165 -- Conditionally inserts New_Item into the map. If Key is already in the
166 -- map, then Inserted returns False and Position designates the node
167 -- containing the existing key/element pair (neither of which is modified).
168 -- If Key is not already in the map, the Inserted returns True and Position
169 -- designates the newly-inserted node container Key and New_Item. The
170 -- search for the key works as follows. Hash is called to determine Key's
171 -- bucket; if the bucket is non-empty, then Equivalent_Keys is called to
172 -- compare Key to each node in that bucket. If the bucket is empty, or
173 -- there were no matching keys in the bucket, the search "fails" and the
174 -- key/item pair is inserted in the map (and Inserted returns True);
175 -- otherwise, the search "succeeds" (and Inserted returns False).
178 (Container
: in out Map
;
180 Position
: out Cursor
;
181 Inserted
: out Boolean);
182 -- The same as the (conditional) Insert that accepts an element parameter,
183 -- with the difference that if Inserted returns True, then the element of
184 -- the newly-inserted node is initialized to its default value.
187 (Container
: in out Map
;
189 New_Item
: Element_Type
);
190 -- Attempts to insert Key into the map, performing the usual search (which
191 -- involves calling both Hash and Equivalent_Keys); if the search succeeds
192 -- (because Key is already in the map), then it raises Constraint_Error.
193 -- (This version of Insert is similar to Replace, but having the opposite
194 -- exception behavior. It is intended for use when you want to assert that
195 -- Key is not already in the map.)
198 (Container
: in out Map
;
200 New_Item
: Element_Type
);
201 -- Attempts to insert Key into the map. If Key is already in the map, then
202 -- both the existing key and element are assigned the values of Key and
203 -- New_Item, respectively. (This version of Insert only raises an exception
204 -- if cursor tampering occurs. It is intended for use when you want to
205 -- insert the key/element pair in the map, and you don't care whether Key
206 -- is already present.)
209 (Container
: in out Map
;
211 New_Item
: Element_Type
);
212 -- Searches for Key in the map; if the search fails (because Key was not in
213 -- the map), then it raises Constraint_Error. Otherwise, both the existing
214 -- key and element are assigned the values of Key and New_Item rsp. (This
215 -- is similar to Insert, but with the opposite exception behavior. It is to
216 -- be used when you want to assert that Key is already in the map.)
218 procedure Exclude
(Container
: in out Map
; Key
: Key_Type
);
219 -- Searches for Key in the map, and if found, removes its node from the map
220 -- and then deallocates it. The search works as follows. The operation
221 -- calls Hash to determine the key's bucket; if the bucket is not empty, it
222 -- calls Equivalent_Keys to compare Key to each key in the bucket. (This is
223 -- the deletion analog of Include. It is intended for use when you want to
224 -- remove the item from the map, but don't care whether the key is already
227 procedure Delete
(Container
: in out Map
; Key
: Key_Type
);
228 -- Searches for Key in the map (which involves calling both Hash and
229 -- Equivalent_Keys). If the search fails, then the operation raises
230 -- Constraint_Error. Otherwise it removes the node from the map and then
231 -- deallocates it. (This is the deletion analog of non-conditional
232 -- Insert. It is intended for use when you want to assert that the item is
233 -- already in the map.)
235 procedure Delete
(Container
: in out Map
; Position
: in out Cursor
);
236 -- Removes the node designated by Position from the map, and then
237 -- deallocates the node. The operation calls Hash to determine the bucket,
238 -- and then compares Position to each node in the bucket until there's a
239 -- match (it does not call Equivalent_Keys).
241 function First
(Container
: Map
) return Cursor
;
242 -- Returns a cursor that designates the first non-empty bucket, by
243 -- searching from the beginning of the buckets array.
245 function Next
(Position
: Cursor
) return Cursor
;
246 -- Returns a cursor that designates the node that follows the current one
247 -- designated by Position. If Position designates the last node in its
248 -- bucket, the operation calls Hash to compute the index of this bucket,
249 -- and searches the buckets array for the first non-empty bucket, starting
250 -- from that index; otherwise, it simply follows the link to the next node
251 -- in the same bucket.
253 procedure Next
(Position
: in out Cursor
);
254 -- Equivalent to Position := Next (Position)
256 function Find
(Container
: Map
; Key
: Key_Type
) return Cursor
;
257 -- Searches for Key in the map. Find calls Hash to determine the key's
258 -- bucket; if the bucket is not empty, it calls Equivalent_Keys to compare
259 -- Key to each key in the bucket. If the search succeeds, Find returns a
260 -- cursor designating the matching node; otherwise, it returns No_Element.
262 function Contains
(Container
: Map
; Key
: Key_Type
) return Boolean;
263 -- Equivalent to Find (Container, Key) /= No_Element
265 function Element
(Container
: Map
; Key
: Key_Type
) return Element_Type
;
266 -- Equivalent to Element (Find (Container, Key))
268 function Equivalent_Keys
(Left
, Right
: Cursor
) return Boolean;
269 -- Returns the result of calling Equivalent_Keys with the keys of the nodes
270 -- designated by cursors Left and Right.
272 function Equivalent_Keys
(Left
: Cursor
; Right
: Key_Type
) return Boolean;
273 -- Returns the result of calling Equivalent_Keys with key of the node
274 -- designated by Left and key Right.
276 function Equivalent_Keys
(Left
: Key_Type
; Right
: Cursor
) return Boolean;
277 -- Returns the result of calling Equivalent_Keys with key Left and the node
278 -- designated by Right.
280 type Constant_Reference_Type
281 (Element
: not null access constant Element_Type
) is private
283 Implicit_Dereference
=> Element
;
286 (Stream
: not null access Root_Stream_Type
'Class;
287 Item
: Constant_Reference_Type
);
289 for Constant_Reference_Type
'Write use Write
;
292 (Stream
: not null access Root_Stream_Type
'Class;
293 Item
: out Constant_Reference_Type
);
295 for Constant_Reference_Type
'Read use Read
;
297 type Reference_Type
(Element
: not null access Element_Type
) is private
299 Implicit_Dereference
=> Element
;
302 (Stream
: not null access Root_Stream_Type
'Class;
303 Item
: Reference_Type
);
305 for Reference_Type
'Write use Write
;
308 (Stream
: not null access Root_Stream_Type
'Class;
309 Item
: out Reference_Type
);
311 for Reference_Type
'Read use Read
;
313 function Constant_Reference
314 (Container
: aliased Map
;
315 Position
: Cursor
) return Constant_Reference_Type
;
318 (Container
: aliased in out Map
;
319 Position
: Cursor
) return Reference_Type
;
321 function Constant_Reference
322 (Container
: aliased Map
;
323 Key
: Key_Type
) return Constant_Reference_Type
;
326 (Container
: aliased in out Map
;
327 Key
: Key_Type
) return Reference_Type
;
331 Process
: not null access procedure (Position
: Cursor
));
332 -- Calls Process for each node in the map
335 (Container
: Map
) return Map_Iterator_Interfaces
.Forward_Iterator
'class;
339 pragma Inline
(Length
);
340 pragma Inline
(Is_Empty
);
341 pragma Inline
(Clear
);
343 pragma Inline
(Element
);
344 pragma Inline
(Move
);
345 pragma Inline
(Contains
);
346 pragma Inline
(Capacity
);
347 pragma Inline
(Reserve_Capacity
);
348 pragma Inline
(Has_Element
);
349 pragma Inline
(Equivalent_Keys
);
350 pragma Inline
(Next
);
353 type Node_Access
is access Node_Type
;
355 type Node_Type
is limited record
357 Element
: Element_Type
;
362 new Hash_Tables
.Generic_Hash_Table_Types
(Node_Type
, Node_Access
);
364 type Map
is new Ada
.Finalization
.Controlled
with record
365 HT
: HT_Types
.Hash_Table_Type
;
369 use Ada
.Finalization
;
371 overriding
procedure Adjust
(Container
: in out Map
);
373 overriding
procedure Finalize
(Container
: in out Map
);
376 (Stream
: not null access Root_Stream_Type
'Class;
379 for Map
'Write use Write
;
382 (Stream
: not null access Root_Stream_Type
'Class;
383 Container
: out Map
);
385 for Map
'Read use Read
;
387 type Map_Access
is access all Map
;
388 for Map_Access
'Storage_Size use 0;
390 type Cursor
is record
391 Container
: Map_Access
;
395 type Constant_Reference_Type
396 (Element
: not null access constant Element_Type
) is null record;
399 (Element
: not null access Element_Type
) is null record;
401 Empty_Map
: constant Map
:= (Controlled
with HT
=> (null, 0, 0, 0));
403 No_Element
: constant Cursor
:= (Container
=> null, Node
=> null);
405 end Ada
.Containers
.Hashed_Maps
;