1 ------------------------------------------------------------------------------
3 -- GNAT LIBRARY COMPONENTS --
5 -- A D A . C O N T A I N E R S . B O U N D E D _ H A S H E D _ M A P S --
9 -- Copyright (C) 2004-2015, 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 with Ada
.Iterator_Interfaces
;
36 private with Ada
.Containers
.Hash_Tables
;
37 private with Ada
.Streams
;
38 private with Ada
.Finalization
;
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
.Bounded_Hashed_Maps
is
49 pragma Annotate
(CodePeer
, Skip_Analysis
);
53 type Map
(Capacity
: Count_Type
; Modulus
: Hash_Type
) is tagged private with
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
);
64 Empty_Map
: constant Map
;
65 -- Map objects declared without an initialization expression are
66 -- initialized to the value Empty_Map.
68 No_Element
: constant Cursor
;
69 -- Cursor objects declared without an initialization expression are
70 -- initialized to the value No_Element.
72 function Has_Element
(Position
: Cursor
) return Boolean;
73 -- Equivalent to Position /= No_Element
75 package Map_Iterator_Interfaces
is new
76 Ada
.Iterator_Interfaces
(Cursor
, Has_Element
);
78 function "=" (Left
, Right
: Map
) return Boolean;
79 -- For each key/element pair in Left, equality attempts to find the key in
80 -- Right; if a search fails the equality returns False. The search works by
81 -- calling Hash to find the bucket in the Right map that corresponds to the
82 -- Left key. If bucket is non-empty, then equality calls Equivalent_Keys
83 -- to compare the key (in Left) to the key of each node in the bucket (in
84 -- Right); if the keys are equivalent, then the equality test for this
85 -- key/element pair (in Left) completes by calling the element equality
86 -- operator to compare the element (in Left) to the element of the node
87 -- (in Right) whose key matched.
89 function Capacity
(Container
: Map
) return Count_Type
;
90 -- Returns the current capacity of the map. Capacity is the maximum length
91 -- before which rehashing in guaranteed not to occur.
93 procedure Reserve_Capacity
(Container
: in out Map
; Capacity
: Count_Type
);
94 -- If the value of the Capacity actual parameter is less or equal to
95 -- Container.Capacity, then the operation has no effect. Otherwise it
96 -- raises Capacity_Error (as no expansion of capacity is possible for a
99 function Default_Modulus
(Capacity
: Count_Type
) return Hash_Type
;
100 -- Returns a modulus value (hash table size) which is optimal for the
101 -- specified capacity (which corresponds to the maximum number of items).
103 function Length
(Container
: Map
) return Count_Type
;
104 -- Returns the number of items in the map
106 function Is_Empty
(Container
: Map
) return Boolean;
107 -- Equivalent to Length (Container) = 0
109 procedure Clear
(Container
: in out Map
);
110 -- Removes all of the items from the map
112 function Key
(Position
: Cursor
) return Key_Type
;
113 -- Returns the key of the node designated by the cursor
115 function Element
(Position
: Cursor
) return Element_Type
;
116 -- Returns the element of the node designated by the cursor
118 procedure Replace_Element
119 (Container
: in out Map
;
121 New_Item
: Element_Type
);
122 -- Assigns the value New_Item to the element designated by the cursor
124 procedure Query_Element
126 Process
: not null access
127 procedure (Key
: Key_Type
; Element
: Element_Type
));
128 -- Calls Process with the key and element (both having only a constant
129 -- view) of the node designed by the cursor.
131 procedure Update_Element
132 (Container
: in out Map
;
134 Process
: not null access
135 procedure (Key
: Key_Type
; Element
: in out Element_Type
));
136 -- Calls Process with the key (with only a constant view) and element (with
137 -- a variable view) of the node designed by the cursor.
139 type Constant_Reference_Type
140 (Element
: not null access constant Element_Type
) is
143 Implicit_Dereference
=> Element
;
145 type Reference_Type
(Element
: not null access Element_Type
) is private
147 Implicit_Dereference
=> Element
;
149 function Constant_Reference
150 (Container
: aliased Map
;
151 Position
: Cursor
) return Constant_Reference_Type
;
154 (Container
: aliased in out Map
;
155 Position
: Cursor
) return Reference_Type
;
157 function Constant_Reference
158 (Container
: aliased Map
;
159 Key
: Key_Type
) return Constant_Reference_Type
;
162 (Container
: aliased in out Map
;
163 Key
: Key_Type
) return Reference_Type
;
165 procedure Assign
(Target
: in out Map
; Source
: Map
);
166 -- If Target denotes the same object as Source, then the operation has no
167 -- effect. If the Target capacity is less than the Source length, then
168 -- Assign raises Capacity_Error. Otherwise, Assign clears Target and then
169 -- copies the (active) elements from Source to Target.
173 Capacity
: Count_Type
:= 0;
174 Modulus
: Hash_Type
:= 0) return Map
;
175 -- Constructs a new set object whose elements correspond to Source. If the
176 -- Capacity parameter is 0, then the capacity of the result is the same as
177 -- the length of Source. If the Capacity parameter is equal or greater than
178 -- the length of Source, then the capacity of the result is the specified
179 -- value. Otherwise, Copy raises Capacity_Error. If the Modulus parameter
180 -- is 0, then the modulus of the result is the value returned by a call to
181 -- Default_Modulus with the capacity parameter determined as above;
182 -- otherwise the modulus of the result is the specified value.
184 procedure Move
(Target
: in out Map
; Source
: in out Map
);
185 -- Clears Target (if it's not empty), and then moves (not copies) the
186 -- buckets array and nodes from Source to Target.
189 (Container
: in out Map
;
191 New_Item
: Element_Type
;
192 Position
: out Cursor
;
193 Inserted
: out Boolean);
194 -- Conditionally inserts New_Item into the map. If Key is already in the
195 -- map, then Inserted returns False and Position designates the node
196 -- containing the existing key/element pair (neither of which is modified).
197 -- If Key is not already in the map, the Inserted returns True and Position
198 -- designates the newly-inserted node container Key and New_Item. The
199 -- search for the key works as follows. Hash is called to determine Key's
200 -- bucket; if the bucket is non-empty, then Equivalent_Keys is called to
201 -- compare Key to each node in that bucket. If the bucket is empty, or
202 -- there were no matching keys in the bucket, the search "fails" and the
203 -- key/item pair is inserted in the map (and Inserted returns True);
204 -- otherwise, the search "succeeds" (and Inserted returns False).
207 (Container
: in out Map
;
209 Position
: out Cursor
;
210 Inserted
: out Boolean);
211 -- The same as the (conditional) Insert that accepts an element parameter,
212 -- with the difference that if Inserted returns True, then the element of
213 -- the newly-inserted node is initialized to its default value.
216 (Container
: in out Map
;
218 New_Item
: Element_Type
);
219 -- Attempts to insert Key into the map, performing the usual search (which
220 -- involves calling both Hash and Equivalent_Keys); if the search succeeds
221 -- (because Key is already in the map), then it raises Constraint_Error.
222 -- (This version of Insert is similar to Replace, but having the opposite
223 -- exception behavior. It is intended for use when you want to assert that
224 -- Key is not already in the map.)
227 (Container
: in out Map
;
229 New_Item
: Element_Type
);
230 -- Attempts to insert Key into the map. If Key is already in the map, then
231 -- both the existing key and element are assigned the values of Key and
232 -- New_Item, respectively. (This version of Insert only raises an exception
233 -- if cursor tampering occurs. It is intended for use when you want to
234 -- insert the key/element pair in the map, and you don't care whether Key
235 -- is already present.)
238 (Container
: in out Map
;
240 New_Item
: Element_Type
);
241 -- Searches for Key in the map; if the search fails (because Key was not in
242 -- the map), then it raises Constraint_Error. Otherwise, both the existing
243 -- key and element are assigned the values of Key and New_Item rsp. (This
244 -- is similar to Insert, but with the opposite exception behavior. It is to
245 -- be used when you want to assert that Key is already in the map.)
247 procedure Exclude
(Container
: in out Map
; Key
: Key_Type
);
248 -- Searches for Key in the map, and if found, removes its node from the map
249 -- and then deallocates it. The search works as follows. The operation
250 -- calls Hash to determine the key's bucket; if the bucket is not empty, it
251 -- calls Equivalent_Keys to compare Key to each key in the bucket. (This is
252 -- the deletion analog of Include. It is intended for use when you want to
253 -- remove the item from the map, but don't care whether the key is already
256 procedure Delete
(Container
: in out Map
; Key
: Key_Type
);
257 -- Searches for Key in the map (which involves calling both Hash and
258 -- Equivalent_Keys). If the search fails, then the operation raises
259 -- Constraint_Error. Otherwise it removes the node from the map and then
260 -- deallocates it. (This is the deletion analog of non-conditional
261 -- Insert. It is intended for use when you want to assert that the item is
262 -- already in the map.)
264 procedure Delete
(Container
: in out Map
; Position
: in out Cursor
);
265 -- Removes the node designated by Position from the map, and then
266 -- deallocates the node. The operation calls Hash to determine the bucket,
267 -- and then compares Position to each node in the bucket until there's a
268 -- match (it does not call Equivalent_Keys).
270 function First
(Container
: Map
) return Cursor
;
271 -- Returns a cursor that designates the first non-empty bucket, by
272 -- searching from the beginning of the buckets array.
274 function Next
(Position
: Cursor
) return Cursor
;
275 -- Returns a cursor that designates the node that follows the current one
276 -- designated by Position. If Position designates the last node in its
277 -- bucket, the operation calls Hash to compute the index of this bucket,
278 -- and searches the buckets array for the first non-empty bucket, starting
279 -- from that index; otherwise, it simply follows the link to the next node
280 -- in the same bucket.
282 procedure Next
(Position
: in out Cursor
);
283 -- Equivalent to Position := Next (Position)
285 function Find
(Container
: Map
; Key
: Key_Type
) return Cursor
;
286 -- Searches for Key in the map. Find calls Hash to determine the key's
287 -- bucket; if the bucket is not empty, it calls Equivalent_Keys to compare
288 -- Key to each key in the bucket. If the search succeeds, Find returns a
289 -- cursor designating the matching node; otherwise, it returns No_Element.
291 function Contains
(Container
: Map
; Key
: Key_Type
) return Boolean;
292 -- Equivalent to Find (Container, Key) /= No_Element
294 function Element
(Container
: Map
; Key
: Key_Type
) return Element_Type
;
295 -- Equivalent to Element (Find (Container, Key))
297 function Equivalent_Keys
(Left
, Right
: Cursor
) return Boolean;
298 -- Returns the result of calling Equivalent_Keys with the keys of the nodes
299 -- designated by cursors Left and Right.
301 function Equivalent_Keys
(Left
: Cursor
; Right
: Key_Type
) return Boolean;
302 -- Returns the result of calling Equivalent_Keys with key of the node
303 -- designated by Left and key Right.
305 function Equivalent_Keys
(Left
: Key_Type
; Right
: Cursor
) return Boolean;
306 -- Returns the result of calling Equivalent_Keys with key Left and the node
307 -- designated by Right.
311 Process
: not null access procedure (Position
: Cursor
));
312 -- Calls Process for each node in the map
314 function Iterate
(Container
: Map
)
315 return Map_Iterator_Interfaces
.Forward_Iterator
'class;
318 pragma Inline
(Length
);
319 pragma Inline
(Is_Empty
);
320 pragma Inline
(Clear
);
322 pragma Inline
(Element
);
323 pragma Inline
(Move
);
324 pragma Inline
(Contains
);
325 pragma Inline
(Capacity
);
326 pragma Inline
(Reserve_Capacity
);
327 pragma Inline
(Has_Element
);
328 pragma Inline
(Next
);
330 type Node_Type
is record
332 Element
: aliased Element_Type
;
337 new Hash_Tables
.Generic_Bounded_Hash_Table_Types
(Node_Type
);
339 type Map
(Capacity
: Count_Type
; Modulus
: Hash_Type
) is
340 new HT_Types
.Hash_Table_Type
(Capacity
, Modulus
) with null record;
342 use HT_Types
, HT_Types
.Implementation
;
344 use Ada
.Finalization
;
347 (Stream
: not null access Root_Stream_Type
'Class;
350 for Map
'Write use Write
;
353 (Stream
: not null access Root_Stream_Type
'Class;
354 Container
: out Map
);
356 for Map
'Read use Read
;
358 type Map_Access
is access all Map
;
359 for Map_Access
'Storage_Size use 0;
361 -- Note: If a Cursor object has no explicit initialization expression,
362 -- it must default initialize to the same value as constant No_Element.
363 -- The Node component of type Cursor has scalar type Count_Type, so it
364 -- requires an explicit initialization expression of its own declaration,
365 -- in order for objects of record type Cursor to properly initialize.
367 type Cursor
is record
368 Container
: Map_Access
;
369 Node
: Count_Type
:= 0;
373 (Stream
: not null access Root_Stream_Type
'Class;
376 for Cursor
'Read use Read
;
379 (Stream
: not null access Root_Stream_Type
'Class;
382 for Cursor
'Write use Write
;
384 subtype Reference_Control_Type
is Implementation
.Reference_Control_Type
;
385 -- It is necessary to rename this here, so that the compiler can find it
387 type Constant_Reference_Type
388 (Element
: not null access constant Element_Type
) is
390 Control
: Reference_Control_Type
:=
391 raise Program_Error
with "uninitialized reference";
392 -- The RM says, "The default initialization of an object of
393 -- type Constant_Reference_Type or Reference_Type propagates
398 (Stream
: not null access Root_Stream_Type
'Class;
399 Item
: Constant_Reference_Type
);
401 for Constant_Reference_Type
'Write use Write
;
404 (Stream
: not null access Root_Stream_Type
'Class;
405 Item
: out Constant_Reference_Type
);
407 for Constant_Reference_Type
'Read use Read
;
409 type Reference_Type
(Element
: not null access Element_Type
) is record
410 Control
: Reference_Control_Type
:=
411 raise Program_Error
with "uninitialized reference";
412 -- The RM says, "The default initialization of an object of
413 -- type Constant_Reference_Type or Reference_Type propagates
418 (Stream
: not null access Root_Stream_Type
'Class;
419 Item
: Reference_Type
);
421 for Reference_Type
'Write use Write
;
424 (Stream
: not null access Root_Stream_Type
'Class;
425 Item
: out Reference_Type
);
427 for Reference_Type
'Read use Read
;
429 -- Three operations are used to optimize in the expansion of "for ... of"
430 -- loops: the Next(Cursor) procedure in the visible part, and the following
431 -- Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for
434 function Pseudo_Reference
435 (Container
: aliased Map
'Class) return Reference_Control_Type
;
436 pragma Inline
(Pseudo_Reference
);
437 -- Creates an object of type Reference_Control_Type pointing to the
438 -- container, and increments the Lock. Finalization of this object will
439 -- decrement the Lock.
441 type Element_Access
is access all Element_Type
with
444 function Get_Element_Access
445 (Position
: Cursor
) return not null Element_Access
;
446 -- Returns a pointer to the element designated by Position.
448 Empty_Map
: constant Map
:=
449 (Hash_Table_Type
with Capacity
=> 0, Modulus
=> 0);
451 No_Element
: constant Cursor
:= (Container
=> null, Node
=> 0);
453 type Iterator
is new Limited_Controlled
and
454 Map_Iterator_Interfaces
.Forward_Iterator
with
456 Container
: Map_Access
;
458 with Disable_Controlled
=> not T_Check
;
460 overriding
procedure Finalize
(Object
: in out Iterator
);
462 overriding
function First
(Object
: Iterator
) return Cursor
;
464 overriding
function Next
466 Position
: Cursor
) return Cursor
;
468 end Ada
.Containers
.Bounded_Hashed_Maps
;