File : a-cihase.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT LIBRARY COMPONENTS --
4 -- --
5 -- ADA.CONTAINERS.INDEFINITE_HASHED_SETS --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 2004-2015, Free Software Foundation, Inc. --
10 -- --
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. --
14 -- --
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. --
21 -- --
22 -- --
23 -- --
24 -- --
25 -- --
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/>. --
30 -- --
31 -- This unit was originally developed by Matthew J Heaney. --
32 ------------------------------------------------------------------------------
33
34 with Ada.Iterator_Interfaces;
35
36 private with Ada.Containers.Hash_Tables;
37 with Ada.Containers.Helpers;
38 private with Ada.Streams;
39 private with Ada.Finalization;
40
41 generic
42 type Element_Type (<>) is private;
43
44 with function Hash (Element : Element_Type) return Hash_Type;
45
46 with function Equivalent_Elements (Left, Right : Element_Type)
47 return Boolean;
48
49 with function "=" (Left, Right : Element_Type) return Boolean is <>;
50
51 package Ada.Containers.Indefinite_Hashed_Sets is
52 pragma Annotate (CodePeer, Skip_Analysis);
53 pragma Preelaborate;
54 pragma Remote_Types;
55
56 type Set is tagged private
57 with Constant_Indexing => Constant_Reference,
58 Default_Iterator => Iterate,
59 Iterator_Element => Element_Type;
60
61 pragma Preelaborable_Initialization (Set);
62
63 type Cursor is private;
64 pragma Preelaborable_Initialization (Cursor);
65
66 Empty_Set : constant Set;
67 -- Set objects declared without an initialization expression are
68 -- initialized to the value Empty_Set.
69
70 No_Element : constant Cursor;
71 -- Cursor objects declared without an initialization expression are
72 -- initialized to the value No_Element.
73
74 function Has_Element (Position : Cursor) return Boolean;
75 -- Equivalent to Position /= No_Element
76
77 package Set_Iterator_Interfaces is new
78 Ada.Iterator_Interfaces (Cursor, Has_Element);
79
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.)
92
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.
97
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.
101
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.
105
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
115 -- deallocated.
116
117 function Length (Container : Set) return Count_Type;
118 -- Returns the number of items in the set
119
120 function Is_Empty (Container : Set) return Boolean;
121 -- Equivalent to Length (Container) = 0
122
123 procedure Clear (Container : in out Set);
124 -- Removes all of the items from the set
125
126 function Element (Position : Cursor) return Element_Type;
127 -- Returns the element of the node designated by the cursor
128
129 procedure Replace_Element
130 (Container : in out Set;
131 Position : Cursor;
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
142 -- its new bucket.
143
144 procedure Query_Element
145 (Position : Cursor;
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.
149
150 type Constant_Reference_Type
151 (Element : not null access constant Element_Type) is private
152 with Implicit_Dereference => Element;
153
154 function Constant_Reference
155 (Container : aliased Set;
156 Position : Cursor) return Constant_Reference_Type;
157 pragma Inline (Constant_Reference);
158
159 procedure Assign (Target : in out Set; Source : Set);
160
161 function Copy (Source : Set; Capacity : Count_Type := 0) return Set;
162
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.
166
167 procedure Insert
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).
184
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.)
193
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.)
202
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.)
210
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.)
219
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.)
227
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).
233
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.
238
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.
242
243 function "or" (Left, Right : Set) return Set renames Union;
244
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.
249
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.
254
255 function "and" (Left, Right : Set) return Set renames Intersection;
256
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.
261
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.
266
267 function "-" (Left, Right : Set) return Set renames Difference;
268
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.
275
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.
283
284 function "xor" (Left, Right : Set) return Set
285 renames Symmetric_Difference;
286
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.
293
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).
301
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.
305
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.
313
314 procedure Next (Position : in out Cursor);
315 -- Equivalent to Position := Next (Position)
316
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.
323
324 function Contains (Container : Set; Item : Element_Type) return Boolean;
325 -- Equivalent to Find (Container, Item) /= No_Element
326
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.
330
331 function Equivalent_Elements
332 (Left : Cursor;
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.
336
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.
342
343 procedure Iterate
344 (Container : Set;
345 Process : not null access procedure (Position : Cursor));
346 -- Calls Process for each node in the set
347
348 function Iterate (Container : Set)
349 return Set_Iterator_Interfaces.Forward_Iterator'Class;
350
351 generic
352 type Key_Type (<>) is private;
353
354 with function Key (Element : Element_Type) return Key_Type;
355
356 with function Hash (Key : Key_Type) return Hash_Type;
357
358 with function Equivalent_Keys (Left, Right : Key_Type) return Boolean;
359
360 package Generic_Keys is
361
362 function Key (Position : Cursor) return Key_Type;
363 -- Applies generic formal operation Key to the element of the node
364 -- designated by Position.
365
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.
369
370 procedure Replace
371 (Container : in out Set;
372 Key : Key_Type;
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
376 -- Replace_Element).
377
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
384 -- bucket.
385
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.
389
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.
398
399 function Contains (Container : Set; Key : Key_Type) return Boolean;
400 -- Equivalent to Find (Container, Key) /= No_Element
401
402 procedure Update_Element_Preserving_Key
403 (Container : in out Set;
404 Position : Cursor;
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.
418
419 type Reference_Type (Element : not null access Element_Type) is private
420 with Implicit_Dereference => Element;
421
422 function Reference_Preserving_Key
423 (Container : aliased in out Set;
424 Position : Cursor) return Reference_Type;
425
426 function Constant_Reference
427 (Container : aliased Set;
428 Key : Key_Type) return Constant_Reference_Type;
429
430 function Reference_Preserving_Key
431 (Container : aliased in out Set;
432 Key : Key_Type) return Reference_Type;
433
434 private
435 type Set_Access is access all Set;
436 for Set_Access'Storage_Size use 0;
437
438 package Impl is new Helpers.Generic_Implementation;
439
440 type Reference_Control_Type is
441 new Impl.Reference_Control_Type with
442 record
443 Container : Set_Access;
444 Index : Hash_Type;
445 Old_Pos : Cursor;
446 Old_Hash : Hash_Type;
447 end record;
448
449 overriding procedure Finalize (Control : in out Reference_Control_Type);
450 pragma Inline (Finalize);
451
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
457 -- Program_Error."
458 end record;
459
460 use Ada.Streams;
461
462 procedure Read
463 (Stream : not null access Root_Stream_Type'Class;
464 Item : out Reference_Type);
465
466 for Reference_Type'Read use Read;
467
468 procedure Write
469 (Stream : not null access Root_Stream_Type'Class;
470 Item : Reference_Type);
471
472 for Reference_Type'Write use Write;
473 end Generic_Keys;
474
475 private
476 pragma Inline (Next);
477
478 type Node_Type;
479 type Node_Access is access Node_Type;
480
481 type Element_Access is access all Element_Type;
482
483 type Node_Type is limited record
484 Element : Element_Access;
485 Next : Node_Access;
486 end record;
487
488 package HT_Types is
489 new Hash_Tables.Generic_Hash_Table_Types (Node_Type, Node_Access);
490
491 type Set is new Ada.Finalization.Controlled with record
492 HT : HT_Types.Hash_Table_Type;
493 end record;
494
495 overriding procedure Adjust (Container : in out Set);
496
497 overriding procedure Finalize (Container : in out Set);
498
499 use HT_Types, HT_Types.Implementation;
500 use Ada.Finalization;
501 use Ada.Streams;
502
503 procedure Write
504 (Stream : not null access Root_Stream_Type'Class;
505 Container : Set);
506
507 for Set'Write use Write;
508
509 procedure Read
510 (Stream : not null access Root_Stream_Type'Class;
511 Container : out Set);
512
513 for Set'Read use Read;
514
515 type Set_Access is access all Set;
516 for Set_Access'Storage_Size use 0;
517
518 type Cursor is record
519 Container : Set_Access;
520 Node : Node_Access;
521 end record;
522
523 procedure Write
524 (Stream : not null access Root_Stream_Type'Class;
525 Item : Cursor);
526
527 for Cursor'Write use Write;
528
529 procedure Read
530 (Stream : not null access Root_Stream_Type'Class;
531 Item : out Cursor);
532
533 for Cursor'Read use Read;
534
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
537
538 type Constant_Reference_Type
539 (Element : not null access constant Element_Type) is
540 record
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
545 -- Program_Error."
546 end record;
547
548 procedure Read
549 (Stream : not null access Root_Stream_Type'Class;
550 Item : out Constant_Reference_Type);
551
552 for Constant_Reference_Type'Read use Read;
553
554 procedure Write
555 (Stream : not null access Root_Stream_Type'Class;
556 Item : Constant_Reference_Type);
557
558 for Constant_Reference_Type'Write use Write;
559
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
563 -- details.
564
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.
571
572 function Get_Element_Access
573 (Position : Cursor) return not null Element_Access;
574 -- Returns a pointer to the element designated by Position.
575
576 Empty_Set : constant Set := (Controlled with others => <>);
577
578 No_Element : constant Cursor := (Container => null, Node => null);
579
580 type Iterator is new Limited_Controlled and
581 Set_Iterator_Interfaces.Forward_Iterator with
582 record
583 Container : Set_Access;
584 end record
585 with Disable_Controlled => not T_Check;
586
587 overriding procedure Finalize (Object : in out Iterator);
588
589 overriding function First (Object : Iterator) return Cursor;
590
591 overriding function Next
592 (Object : Iterator;
593 Position : Cursor) return Cursor;
594
595 end Ada.Containers.Indefinite_Hashed_Sets;