1 ------------------------------------------------------------------------------
3 -- GNAT LIBRARY COMPONENTS --
5 -- ADA.CONTAINERS.INDEFINITE_HASHED_SETS --
9 -- Copyright (C) 2004-2018, 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 with Ada
.Containers
.Helpers
;
38 private with Ada
.Streams
;
39 private with Ada
.Finalization
;
42 type Element_Type
(<>) is private;
44 with function Hash
(Element
: Element_Type
) return Hash_Type
;
46 with function Equivalent_Elements
(Left
, Right
: Element_Type
)
49 with function "=" (Left
, Right
: Element_Type
) return Boolean is <>;
51 package Ada
.Containers
.Indefinite_Hashed_Sets
is
52 pragma Annotate
(CodePeer
, Skip_Analysis
);
56 type Set
is tagged private
57 with Constant_Indexing
=> Constant_Reference
,
58 Default_Iterator
=> Iterate
,
59 Iterator_Element
=> Element_Type
;
61 pragma Preelaborable_Initialization
(Set
);
63 type Cursor
is private;
64 pragma Preelaborable_Initialization
(Cursor
);
66 Empty_Set
: constant Set
;
67 -- Set objects declared without an initialization expression are
68 -- initialized to the value Empty_Set.
70 No_Element
: constant Cursor
;
71 -- Cursor objects declared without an initialization expression are
72 -- initialized to the value No_Element.
74 function Has_Element
(Position
: Cursor
) return Boolean;
75 -- Equivalent to Position /= No_Element
77 package Set_Iterator_Interfaces
is new
78 Ada
.Iterator_Interfaces
(Cursor
, Has_Element
);
80 function "=" (Left
, Right
: Set
) return Boolean;
81 -- For each element in Left, set equality attempts to find the equal
82 -- element in Right; if a search fails, then set equality immediately
83 -- returns False. The search works by calling Hash to find the bucket in
84 -- the Right set that corresponds to the Left element. If the bucket is
85 -- non-empty, the search calls the generic formal element equality operator
86 -- to compare the element (in Left) to the element of each node in the
87 -- bucket (in Right); the search terminates when a matching node in the
88 -- bucket is found, or the nodes in the bucket are exhausted. (Note that
89 -- element equality is called here, not Equivalent_Elements. Set equality
90 -- is the only operation in which element equality is used. Compare set
91 -- equality to Equivalent_Sets, which does call Equivalent_Elements.)
93 function Equivalent_Sets
(Left
, Right
: Set
) return Boolean;
94 -- Similar to set equality, with the difference that the element in Left is
95 -- compared to the elements in Right using the generic formal
96 -- Equivalent_Elements operation instead of element equality.
98 function To_Set
(New_Item
: Element_Type
) return Set
;
99 -- Constructs a singleton set comprising New_Element. To_Set calls Hash to
100 -- determine the bucket for New_Item.
102 function Capacity
(Container
: Set
) return Count_Type
;
103 -- Returns the current capacity of the set. Capacity is the maximum length
104 -- before which rehashing in guaranteed not to occur.
106 procedure Reserve_Capacity
(Container
: in out Set
; Capacity
: Count_Type
);
107 -- Adjusts the current capacity, by allocating a new buckets array. If the
108 -- requested capacity is less than the current capacity, then the capacity
109 -- is contracted (to a value not less than the current length). If the
110 -- requested capacity is greater than the current capacity, then the
111 -- capacity is expanded (to a value not less than what is requested). In
112 -- either case, the nodes are rehashed from the old buckets array onto the
113 -- new buckets array (Hash is called once for each existing element in
114 -- order to compute the new index), and then the old buckets array is
117 function Length
(Container
: Set
) return Count_Type
;
118 -- Returns the number of items in the set
120 function Is_Empty
(Container
: Set
) return Boolean;
121 -- Equivalent to Length (Container) = 0
123 procedure Clear
(Container
: in out Set
);
124 -- Removes all of the items from the set
126 function Element
(Position
: Cursor
) return Element_Type
;
127 -- Returns the element of the node designated by the cursor
129 procedure Replace_Element
130 (Container
: in out Set
;
132 New_Item
: Element_Type
);
133 -- If New_Item is equivalent (as determined by calling Equivalent_Elements)
134 -- to the element of the node designated by Position, then New_Element is
135 -- assigned to that element. Otherwise, it calls Hash to determine the
136 -- bucket for New_Item. If the bucket is not empty, then it calls
137 -- Equivalent_Elements for each node in that bucket to determine whether
138 -- New_Item is equivalent to an element in that bucket. If
139 -- Equivalent_Elements returns True then Program_Error is raised (because
140 -- an element may appear only once in the set); otherwise, New_Item is
141 -- assigned to the node designated by Position, and the node is moved to
144 procedure Query_Element
146 Process
: not null access procedure (Element
: Element_Type
));
147 -- Calls Process with the element (having only a constant view) of the node
148 -- designated by the cursor.
150 type Constant_Reference_Type
151 (Element
: not null access constant Element_Type
) is private
152 with Implicit_Dereference
=> Element
;
154 function Constant_Reference
155 (Container
: aliased Set
;
156 Position
: Cursor
) return Constant_Reference_Type
;
157 pragma Inline
(Constant_Reference
);
159 procedure Assign
(Target
: in out Set
; Source
: Set
);
161 function Copy
(Source
: Set
; Capacity
: Count_Type
:= 0) return Set
;
163 procedure Move
(Target
: in out Set
; Source
: in out Set
);
164 -- Clears Target (if it's not empty), and then moves (not copies) the
165 -- buckets array and nodes from Source to Target.
168 (Container
: in out Set
;
169 New_Item
: Element_Type
;
170 Position
: out Cursor
;
171 Inserted
: out Boolean);
172 -- Conditionally inserts New_Item into the set. If New_Item is already in
173 -- the set, then Inserted returns False and Position designates the node
174 -- containing the existing element (which is not modified). If New_Item is
175 -- not already in the set, then Inserted returns True and Position
176 -- designates the newly-inserted node containing New_Item. The search for
177 -- an existing element works as follows. Hash is called to determine
178 -- New_Item's bucket; if the bucket is non-empty, then Equivalent_Elements
179 -- is called to compare New_Item to the element of each node in that
180 -- bucket. If the bucket is empty, or there were no equivalent elements in
181 -- the bucket, the search "fails" and the New_Item is inserted in the set
182 -- (and Inserted returns True); otherwise, the search "succeeds" (and
183 -- Inserted returns False).
185 procedure Insert
(Container
: in out Set
; New_Item
: Element_Type
);
186 -- Attempts to insert New_Item into the set, performing the usual insertion
187 -- search (which involves calling both Hash and Equivalent_Elements); if
188 -- the search succeeds (New_Item is equivalent to an element already in the
189 -- set, and so was not inserted), then this operation raises
190 -- Constraint_Error. (This version of Insert is similar to Replace, but
191 -- having the opposite exception behavior. It is intended for use when you
192 -- want to assert that the item is not already in the set.)
194 procedure Include
(Container
: in out Set
; New_Item
: Element_Type
);
195 -- Attempts to insert New_Item into the set. If an element equivalent to
196 -- New_Item is already in the set (the insertion search succeeded, and
197 -- hence New_Item was not inserted), then the value of New_Item is assigned
198 -- to the existing element. (This insertion operation only raises an
199 -- exception if cursor tampering occurs. It is intended for use when you
200 -- want to insert the item in the set, and you don't care whether an
201 -- equivalent element is already present.)
203 procedure Replace
(Container
: in out Set
; New_Item
: Element_Type
);
204 -- Searches for New_Item in the set; if the search fails (because an
205 -- equivalent element was not in the set), then it raises
206 -- Constraint_Error. Otherwise, the existing element is assigned the value
207 -- New_Item. (This is similar to Insert, but with the opposite exception
208 -- behavior. It is intended for use when you want to assert that the item
209 -- is already in the set.)
211 procedure Exclude
(Container
: in out Set
; Item
: Element_Type
);
212 -- Searches for Item in the set, and if found, removes its node from the
213 -- set and then deallocates it. The search works as follows. The operation
214 -- calls Hash to determine the item's bucket; if the bucket is not empty,
215 -- it calls Equivalent_Elements to compare Item to the element of each node
216 -- in the bucket. (This is the deletion analog of Include. It is intended
217 -- for use when you want to remove the item from the set, but don't care
218 -- whether the item is already in the set.)
220 procedure Delete
(Container
: in out Set
; Item
: Element_Type
);
221 -- Searches for Item in the set (which involves calling both Hash and
222 -- Equivalent_Elements). If the search fails, then the operation raises
223 -- Constraint_Error. Otherwise it removes the node from the set and then
224 -- deallocates it. (This is the deletion analog of non-conditional
225 -- Insert. It is intended for use when you want to assert that the item is
226 -- already in the set.)
228 procedure Delete
(Container
: in out Set
; Position
: in out Cursor
);
229 -- Removes the node designated by Position from the set, and then
230 -- deallocates the node. The operation calls Hash to determine the bucket,
231 -- and then compares Position to each node in the bucket until there's a
232 -- match (it does not call Equivalent_Elements).
234 procedure Union
(Target
: in out Set
; Source
: Set
);
235 -- The operation first calls Reserve_Capacity if the current capacity is
236 -- less than the sum of the lengths of Source and Target. It then iterates
237 -- over the Source set, and conditionally inserts each element into Target.
239 function Union
(Left
, Right
: Set
) return Set
;
240 -- The operation first copies the Left set to the result, and then iterates
241 -- over the Right set to conditionally insert each element into the result.
243 function "or" (Left
, Right
: Set
) return Set
renames Union
;
245 procedure Intersection
(Target
: in out Set
; Source
: Set
);
246 -- Iterates over the Target set (calling First and Next), calling Find to
247 -- determine whether the element is in Source. If an equivalent element is
248 -- not found in Source, the element is deleted from Target.
250 function Intersection
(Left
, Right
: Set
) return Set
;
251 -- Iterates over the Left set, calling Find to determine whether the
252 -- element is in Right. If an equivalent element is found, it is inserted
253 -- into the result set.
255 function "and" (Left
, Right
: Set
) return Set
renames Intersection
;
257 procedure Difference
(Target
: in out Set
; Source
: Set
);
258 -- Iterates over the Source (calling First and Next), calling Find to
259 -- determine whether the element is in Target. If an equivalent element is
260 -- found, it is deleted from Target.
262 function Difference
(Left
, Right
: Set
) return Set
;
263 -- Iterates over the Left set, calling Find to determine whether the
264 -- element is in the Right set. If an equivalent element is not found, the
265 -- element is inserted into the result set.
267 function "-" (Left
, Right
: Set
) return Set
renames Difference
;
269 procedure Symmetric_Difference
(Target
: in out Set
; Source
: Set
);
270 -- The operation first calls Reserve_Capacity if the current capacity is
271 -- less than the sum of the lengths of Source and Target. It then iterates
272 -- over the Source set, searching for the element in Target (calling Hash
273 -- and Equivalent_Elements). If an equivalent element is found, it is
274 -- removed from Target; otherwise it is inserted into Target.
276 function Symmetric_Difference
(Left
, Right
: Set
) return Set
;
277 -- The operation first iterates over the Left set. It calls Find to
278 -- determine whether the element is in the Right set. If no equivalent
279 -- element is found, the element from Left is inserted into the result. The
280 -- operation then iterates over the Right set, to determine whether the
281 -- element is in the Left set. If no equivalent element is found, the Right
282 -- element is inserted into the result.
284 function "xor" (Left
, Right
: Set
) return Set
285 renames Symmetric_Difference
;
287 function Overlap
(Left
, Right
: Set
) return Boolean;
288 -- Iterates over the Left set (calling First and Next), calling Find to
289 -- determine whether the element is in the Right set. If an equivalent
290 -- element is found, the operation immediately returns True. The operation
291 -- returns False if the iteration over Left terminates without finding any
292 -- equivalent element in Right.
294 function Is_Subset
(Subset
: Set
; Of_Set
: Set
) return Boolean;
295 -- Iterates over Subset (calling First and Next), calling Find to determine
296 -- whether the element is in Of_Set. If no equivalent element is found in
297 -- Of_Set, the operation immediately returns False. The operation returns
298 -- True if the iteration over Subset terminates without finding an element
299 -- not in Of_Set (that is, every element in Subset is equivalent to an
300 -- element in Of_Set).
302 function First
(Container
: Set
) return Cursor
;
303 -- Returns a cursor that designates the first non-empty bucket, by
304 -- searching from the beginning of the buckets array.
306 function Next
(Position
: Cursor
) return Cursor
;
307 -- Returns a cursor that designates the node that follows the current one
308 -- designated by Position. If Position designates the last node in its
309 -- bucket, the operation calls Hash to compute the index of this bucket,
310 -- and searches the buckets array for the first non-empty bucket, starting
311 -- from that index; otherwise, it simply follows the link to the next node
312 -- in the same bucket.
314 procedure Next
(Position
: in out Cursor
);
315 -- Equivalent to Position := Next (Position)
317 function Find
(Container
: Set
; Item
: Element_Type
) return Cursor
;
318 -- Searches for Item in the set. Find calls Hash to determine the item's
319 -- bucket; if the bucket is not empty, it calls Equivalent_Elements to
320 -- compare Item to each element in the bucket. If the search succeeds, Find
321 -- returns a cursor designating the node containing the equivalent element;
322 -- otherwise, it returns No_Element.
324 function Contains
(Container
: Set
; Item
: Element_Type
) return Boolean;
325 -- Equivalent to Find (Container, Item) /= No_Element
327 function Equivalent_Elements
(Left
, Right
: Cursor
) return Boolean;
328 -- Returns the result of calling Equivalent_Elements with the elements of
329 -- the nodes designated by cursors Left and Right.
331 function Equivalent_Elements
333 Right
: Element_Type
) return Boolean;
334 -- Returns the result of calling Equivalent_Elements with element of the
335 -- node designated by Left and element Right.
337 function Equivalent_Elements
338 (Left
: Element_Type
;
339 Right
: Cursor
) return Boolean;
340 -- Returns the result of calling Equivalent_Elements with element Left and
341 -- the element of the node designated by Right.
345 Process
: not null access procedure (Position
: Cursor
));
346 -- Calls Process for each node in the set
348 function Iterate
(Container
: Set
)
349 return Set_Iterator_Interfaces
.Forward_Iterator
'Class;
352 type Key_Type
(<>) is private;
354 with function Key
(Element
: Element_Type
) return Key_Type
;
356 with function Hash
(Key
: Key_Type
) return Hash_Type
;
358 with function Equivalent_Keys
(Left
, Right
: Key_Type
) return Boolean;
360 package Generic_Keys
is
362 function Key
(Position
: Cursor
) return Key_Type
;
363 -- Applies generic formal operation Key to the element of the node
364 -- designated by Position.
366 function Element
(Container
: Set
; Key
: Key_Type
) return Element_Type
;
367 -- Searches (as per the key-based Find) for the node containing Key, and
368 -- returns the associated element.
371 (Container
: in out Set
;
373 New_Item
: Element_Type
);
374 -- Searches (as per the key-based Find) for the node containing Key, and
375 -- then replaces the element of that node (as per the element-based
378 procedure Exclude
(Container
: in out Set
; Key
: Key_Type
);
379 -- Searches for Key in the set, and if found, removes its node from the
380 -- set and then deallocates it. The search works by first calling Hash
381 -- (on Key) to determine the bucket; if the bucket is not empty, it
382 -- calls Equivalent_Keys to compare parameter Key to the value of
383 -- generic formal operation Key applied to element of each node in the
386 procedure Delete
(Container
: in out Set
; Key
: Key_Type
);
387 -- Deletes the node containing Key as per Exclude, with the difference
388 -- that Constraint_Error is raised if Key is not found.
390 function Find
(Container
: Set
; Key
: Key_Type
) return Cursor
;
391 -- Searches for the node containing Key, and returns a cursor
392 -- designating the node. The search works by first calling Hash (on Key)
393 -- to determine the bucket. If the bucket is not empty, the search
394 -- compares Key to the element of each node in the bucket, and returns
395 -- the matching node. The comparison itself works by applying the
396 -- generic formal Key operation to the element of the node, and then
397 -- calling generic formal operation Equivalent_Keys.
399 function Contains
(Container
: Set
; Key
: Key_Type
) return Boolean;
400 -- Equivalent to Find (Container, Key) /= No_Element
402 procedure Update_Element_Preserving_Key
403 (Container
: in out Set
;
405 Process
: not null access
406 procedure (Element
: in out Element_Type
));
407 -- Calls Process with the element of the node designated by Position,
408 -- but with the restriction that the key-value of the element is not
409 -- modified. The operation first makes a copy of the value returned by
410 -- applying generic formal operation Key on the element of the node, and
411 -- then calls Process with the element. The operation verifies that the
412 -- key-part has not been modified by calling generic formal operation
413 -- Equivalent_Keys to compare the saved key-value to the value returned
414 -- by applying generic formal operation Key to the post-Process value of
415 -- element. If the key values compare equal then the operation
416 -- completes. Otherwise, the node is removed from the map and
417 -- Program_Error is raised.
419 type Reference_Type
(Element
: not null access Element_Type
) is private
420 with Implicit_Dereference
=> Element
;
422 function Reference_Preserving_Key
423 (Container
: aliased in out Set
;
424 Position
: Cursor
) return Reference_Type
;
426 function Constant_Reference
427 (Container
: aliased Set
;
428 Key
: Key_Type
) return Constant_Reference_Type
;
430 function Reference_Preserving_Key
431 (Container
: aliased in out Set
;
432 Key
: Key_Type
) return Reference_Type
;
435 type Set_Access
is access all Set
;
436 for Set_Access
'Storage_Size use 0;
438 package Impl
is new Helpers
.Generic_Implementation
;
440 type Reference_Control_Type
is
441 new Impl
.Reference_Control_Type
with
443 Container
: Set_Access
;
446 Old_Hash
: Hash_Type
;
449 overriding
procedure Finalize
(Control
: in out Reference_Control_Type
);
450 pragma Inline
(Finalize
);
452 type Reference_Type
(Element
: not null access Element_Type
) is record
453 Control
: Reference_Control_Type
:=
454 raise Program_Error
with "uninitialized reference";
455 -- The RM says, "The default initialization of an object of
456 -- type Constant_Reference_Type or Reference_Type propagates
463 (Stream
: not null access Root_Stream_Type
'Class;
464 Item
: out Reference_Type
);
466 for Reference_Type
'Read use Read
;
469 (Stream
: not null access Root_Stream_Type
'Class;
470 Item
: Reference_Type
);
472 for Reference_Type
'Write use Write
;
476 pragma Inline
(Next
);
479 type Node_Access
is access Node_Type
;
481 type Element_Access
is access all Element_Type
;
483 type Node_Type
is limited record
484 Element
: Element_Access
;
489 new Hash_Tables
.Generic_Hash_Table_Types
(Node_Type
, Node_Access
);
491 type Set
is new Ada
.Finalization
.Controlled
with record
492 HT
: HT_Types
.Hash_Table_Type
;
495 overriding
procedure Adjust
(Container
: in out Set
);
497 overriding
procedure Finalize
(Container
: in out Set
);
499 use HT_Types
, HT_Types
.Implementation
;
500 use Ada
.Finalization
;
504 (Stream
: not null access Root_Stream_Type
'Class;
507 for Set
'Write use Write
;
510 (Stream
: not null access Root_Stream_Type
'Class;
511 Container
: out Set
);
513 for Set
'Read use Read
;
515 type Set_Access
is access all Set
;
516 for Set_Access
'Storage_Size use 0;
518 type Cursor
is record
519 Container
: Set_Access
;
524 (Stream
: not null access Root_Stream_Type
'Class;
527 for Cursor
'Write use Write
;
530 (Stream
: not null access Root_Stream_Type
'Class;
533 for Cursor
'Read use Read
;
535 subtype Reference_Control_Type
is Implementation
.Reference_Control_Type
;
536 -- It is necessary to rename this here, so that the compiler can find it
538 type Constant_Reference_Type
539 (Element
: not null access constant Element_Type
) is
541 Control
: Reference_Control_Type
:=
542 raise Program_Error
with "uninitialized reference";
543 -- The RM says, "The default initialization of an object of
544 -- type Constant_Reference_Type or Reference_Type propagates
549 (Stream
: not null access Root_Stream_Type
'Class;
550 Item
: out Constant_Reference_Type
);
552 for Constant_Reference_Type
'Read use Read
;
555 (Stream
: not null access Root_Stream_Type
'Class;
556 Item
: Constant_Reference_Type
);
558 for Constant_Reference_Type
'Write use Write
;
560 -- Three operations are used to optimize in the expansion of "for ... of"
561 -- loops: the Next(Cursor) procedure in the visible part, and the following
562 -- Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for
565 function Pseudo_Reference
566 (Container
: aliased Set
'Class) return Reference_Control_Type
;
567 pragma Inline
(Pseudo_Reference
);
568 -- Creates an object of type Reference_Control_Type pointing to the
569 -- container, and increments the Lock. Finalization of this object will
570 -- decrement the Lock.
572 function Get_Element_Access
573 (Position
: Cursor
) return not null Element_Access
;
574 -- Returns a pointer to the element designated by Position.
576 Empty_Set
: constant Set
:= (Controlled
with others => <>);
578 No_Element
: constant Cursor
:= (Container
=> null, Node
=> null);
580 type Iterator
is new Limited_Controlled
and
581 Set_Iterator_Interfaces
.Forward_Iterator
with
583 Container
: Set_Access
;
585 with Disable_Controlled
=> not T_Check
;
587 overriding
procedure Finalize
(Object
: in out Iterator
);
589 overriding
function First
(Object
: Iterator
) return Cursor
;
591 overriding
function Next
593 Position
: Cursor
) return Cursor
;
595 end Ada
.Containers
.Indefinite_Hashed_Sets
;