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 type Constant_Reference_Type
152 (Element : not null access constant Element_Type) is private
154 Implicit_Dereference => Element;
157 (Stream : not null access Root_Stream_Type'Class;
158 Item : Constant_Reference_Type);
160 for Constant_Reference_Type'Write use Write;
163 (Stream : not null access Root_Stream_Type'Class;
164 Item : out Constant_Reference_Type);
166 for Constant_Reference_Type'Read use Read;
168 type Reference_Type (Element : not null access Element_Type) is private
170 Implicit_Dereference => Element;
173 (Stream : not null access Root_Stream_Type'Class;
174 Item : Reference_Type);
176 for Reference_Type'Write use Write;
179 (Stream : not null access Root_Stream_Type'Class;
180 Item : out Reference_Type);
182 for Reference_Type'Read use Read;
184 function Constant_Reference
185 (Container : aliased Map;
186 Position : Cursor) return Constant_Reference_Type;
189 (Container : aliased in out Map;
190 Position : Cursor) return Reference_Type;
192 function Constant_Reference
193 (Container : aliased Map;
194 Key : Key_Type) return Constant_Reference_Type;
197 (Container : aliased in out Map;
198 Key : Key_Type) return Reference_Type;
200 procedure Assign (Target : in out Map; Source : Map);
202 function Copy (Source : Map; Capacity : Count_Type := 0) return Map;
204 procedure Move (Target : in out Map; Source : in out Map);
205 -- Clears Target (if it's not empty), and then moves (not copies) the
206 -- buckets array and nodes from Source to Target.
209 (Container : in out Map;
211 New_Item : Element_Type;
212 Position : out Cursor;
213 Inserted : out Boolean);
214 -- Conditionally inserts New_Item into the map. If Key is already in the
215 -- map, then Inserted returns False and Position designates the node
216 -- containing the existing key/element pair (neither of which is modified).
217 -- If Key is not already in the map, the Inserted returns True and Position
218 -- designates the newly-inserted node container Key and New_Item. The
219 -- search for the key works as follows. Hash is called to determine Key's
220 -- bucket; if the bucket is non-empty, then Equivalent_Keys is called to
221 -- compare Key to each node in that bucket. If the bucket is empty, or
222 -- there were no matching keys in the bucket, the search "fails" and the
223 -- key/item pair is inserted in the map (and Inserted returns True);
224 -- otherwise, the search "succeeds" (and Inserted returns False).
227 (Container : in out Map;
229 Position : out Cursor;
230 Inserted : out Boolean);
231 -- The same as the (conditional) Insert that accepts an element parameter,
232 -- with the difference that if Inserted returns True, then the element of
233 -- the newly-inserted node is initialized to its default value.
236 (Container : in out Map;
238 New_Item : Element_Type);
239 -- Attempts to insert Key into the map, performing the usual search (which
240 -- involves calling both Hash and Equivalent_Keys); if the search succeeds
241 -- (because Key is already in the map), then it raises Constraint_Error.
242 -- (This version of Insert is similar to Replace, but having the opposite
243 -- exception behavior. It is intended for use when you want to assert that
244 -- Key is not already in the map.)
247 (Container : in out Map;
249 New_Item : Element_Type);
250 -- Attempts to insert Key into the map. If Key is already in the map, then
251 -- both the existing key and element are assigned the values of Key and
252 -- New_Item, respectively. (This version of Insert only raises an exception
253 -- if cursor tampering occurs. It is intended for use when you want to
254 -- insert the key/element pair in the map, and you don't care whether Key
255 -- is already present.)
258 (Container : in out Map;
260 New_Item : Element_Type);
261 -- Searches for Key in the map; if the search fails (because Key was not in
262 -- the map), then it raises Constraint_Error. Otherwise, both the existing
263 -- key and element are assigned the values of Key and New_Item rsp. (This
264 -- is similar to Insert, but with the opposite exception behavior. It is to
265 -- be used when you want to assert that Key is already in the map.)
267 procedure Exclude (Container : in out Map; Key : Key_Type);
268 -- Searches for Key in the map, and if found, removes its node from the map
269 -- and then deallocates it. The search works as follows. The operation
270 -- calls Hash to determine the key's bucket; if the bucket is not empty, it
271 -- calls Equivalent_Keys to compare Key to each key in the bucket. (This is
272 -- the deletion analog of Include. It is intended for use when you want to
273 -- remove the item from the map, but don't care whether the key is already
276 procedure Delete (Container : in out Map; Key : Key_Type);
277 -- Searches for Key in the map (which involves calling both Hash and
278 -- Equivalent_Keys). If the search fails, then the operation raises
279 -- Constraint_Error. Otherwise it removes the node from the map and then
280 -- deallocates it. (This is the deletion analog of non-conditional
281 -- Insert. It is intended for use when you want to assert that the item is
282 -- already in the map.)
284 procedure Delete (Container : in out Map; Position : in out Cursor);
285 -- Removes the node designated by Position from the map, and then
286 -- deallocates the node. The operation calls Hash to determine the bucket,
287 -- and then compares Position to each node in the bucket until there's a
288 -- match (it does not call Equivalent_Keys).
290 function First (Container : Map) return Cursor;
291 -- Returns a cursor that designates the first non-empty bucket, by
292 -- searching from the beginning of the buckets array.
294 function Next (Position : Cursor) return Cursor;
295 -- Returns a cursor that designates the node that follows the current one
296 -- designated by Position. If Position designates the last node in its
297 -- bucket, the operation calls Hash to compute the index of this bucket,
298 -- and searches the buckets array for the first non-empty bucket, starting
299 -- from that index; otherwise, it simply follows the link to the next node
300 -- in the same bucket.
302 procedure Next (Position : in out Cursor);
303 -- Equivalent to Position := Next (Position)
305 function Find (Container : Map; Key : Key_Type) return Cursor;
306 -- Searches for Key in the map. Find calls Hash to determine the key's
307 -- bucket; if the bucket is not empty, it calls Equivalent_Keys to compare
308 -- Key to each key in the bucket. If the search succeeds, Find returns a
309 -- cursor designating the matching node; otherwise, it returns No_Element.
311 function Contains (Container : Map; Key : Key_Type) return Boolean;
312 -- Equivalent to Find (Container, Key) /= No_Element
314 function Element (Container : Map; Key : Key_Type) return Element_Type;
315 -- Equivalent to Element (Find (Container, Key))
317 function Equivalent_Keys (Left, Right : Cursor) return Boolean;
318 -- Returns the result of calling Equivalent_Keys with the keys of the nodes
319 -- designated by cursors Left and Right.
321 function Equivalent_Keys (Left : Cursor; Right : Key_Type) return Boolean;
322 -- Returns the result of calling Equivalent_Keys with key of the node
323 -- designated by Left and key Right.
325 function Equivalent_Keys (Left : Key_Type; Right : Cursor) return Boolean;
326 -- Returns the result of calling Equivalent_Keys with key Left and the node
327 -- designated by Right.
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 : aliased 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;