1 ------------------------------------------------------------------------------
3 -- GNAT LIBRARY COMPONENTS --
5 -- ADA.CONTAINERS.INDEFINITE_HASHED_SETS --
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 with Ada.Iterator_Interfaces;
35 private with Ada.Containers.Hash_Tables;
36 private with Ada.Streams;
37 private with Ada.Finalization;
40 type Element_Type (<>) is private;
42 with function Hash (Element : Element_Type) return Hash_Type;
44 with function Equivalent_Elements (Left, Right : Element_Type)
47 with function "=" (Left, Right : Element_Type) return Boolean is <>;
49 package Ada.Containers.Indefinite_Hashed_Sets is
53 type Set is tagged private
54 with Constant_Indexing => Constant_Reference,
55 Default_Iterator => Iterate,
56 Iterator_Element => Element_Type;
58 pragma Preelaborable_Initialization (Set);
60 type Cursor is private;
61 pragma Preelaborable_Initialization (Cursor);
63 Empty_Set : constant Set;
64 -- Set objects declared without an initialization expression are
65 -- initialized to the value Empty_Set.
67 No_Element : constant Cursor;
68 -- Cursor objects declared without an initialization expression are
69 -- initialized to the value No_Element.
71 function Has_Element (Position : Cursor) return Boolean;
72 -- Equivalent to Position /= No_Element
74 package Set_Iterator_Interfaces is new
75 Ada.Iterator_Interfaces (Cursor, Has_Element);
77 function "=" (Left, Right : Set) return Boolean;
78 -- For each element in Left, set equality attempts to find the equal
79 -- element in Right; if a search fails, then set equality immediately
80 -- returns False. The search works by calling Hash to find the bucket in
81 -- the Right set that corresponds to the Left element. If the bucket is
82 -- non-empty, the search calls the generic formal element equality operator
83 -- to compare the element (in Left) to the element of each node in the
84 -- bucket (in Right); the search terminates when a matching node in the
85 -- bucket is found, or the nodes in the bucket are exhausted. (Note that
86 -- element equality is called here, not Equivalent_Elements. Set equality
87 -- is the only operation in which element equality is used. Compare set
88 -- equality to Equivalent_Sets, which does call Equivalent_Elements.)
90 function Equivalent_Sets (Left, Right : Set) return Boolean;
91 -- Similar to set equality, with the difference that the element in Left is
92 -- compared to the elements in Right using the generic formal
93 -- Equivalent_Elements operation instead of element equality.
95 function To_Set (New_Item : Element_Type) return Set;
96 -- Constructs a singleton set comprising New_Element. To_Set calls Hash to
97 -- determine the bucket for New_Item.
99 function Capacity (Container : Set) return Count_Type;
100 -- Returns the current capacity of the set. Capacity is the maximum length
101 -- before which rehashing in guaranteed not to occur.
103 procedure Reserve_Capacity (Container : in out Set; Capacity : Count_Type);
104 -- Adjusts the current capacity, by allocating a new buckets array. If the
105 -- requested capacity is less than the current capacity, then the capacity
106 -- is contracted (to a value not less than the current length). If the
107 -- requested capacity is greater than the current capacity, then the
108 -- capacity is expanded (to a value not less than what is requested). In
109 -- either case, the nodes are rehashed from the old buckets array onto the
110 -- new buckets array (Hash is called once for each existing element in
111 -- order to compute the new index), and then the old buckets array is
114 function Length (Container : Set) return Count_Type;
115 -- Returns the number of items in the set
117 function Is_Empty (Container : Set) return Boolean;
118 -- Equivalent to Length (Container) = 0
120 procedure Clear (Container : in out Set);
121 -- Removes all of the items from the set
123 function Element (Position : Cursor) return Element_Type;
124 -- Returns the element of the node designated by the cursor
126 procedure Replace_Element
127 (Container : in out Set;
129 New_Item : Element_Type);
130 -- If New_Item is equivalent (as determined by calling Equivalent_Elements)
131 -- to the element of the node designated by Position, then New_Element is
132 -- assigned to that element. Otherwise, it calls Hash to determine the
133 -- bucket for New_Item. If the bucket is not empty, then it calls
134 -- Equivalent_Elements for each node in that bucket to determine whether
135 -- New_Item is equivalent to an element in that bucket. If
136 -- Equivalent_Elements returns True then Program_Error is raised (because
137 -- an element may appear only once in the set); otherwise, New_Item is
138 -- assigned to the node designated by Position, and the node is moved to
141 procedure Query_Element
143 Process : not null access procedure (Element : Element_Type));
144 -- Calls Process with the element (having only a constant view) of the node
145 -- designated by the cursor.
147 type Constant_Reference_Type
148 (Element : not null access constant Element_Type) is private
149 with Implicit_Dereference => Element;
151 function Constant_Reference
152 (Container : aliased Set;
153 Position : Cursor) return Constant_Reference_Type;
155 procedure Assign (Target : in out Set; Source : Set);
157 function Copy (Source : Set; Capacity : Count_Type := 0) return Set;
159 procedure Move (Target : in out Set; Source : in out Set);
160 -- Clears Target (if it's not empty), and then moves (not copies) the
161 -- buckets array and nodes from Source to Target.
164 (Container : in out Set;
165 New_Item : Element_Type;
166 Position : out Cursor;
167 Inserted : out Boolean);
168 -- Conditionally inserts New_Item into the set. If New_Item is already in
169 -- the set, then Inserted returns False and Position designates the node
170 -- containing the existing element (which is not modified). If New_Item is
171 -- not already in the set, then Inserted returns True and Position
172 -- designates the newly-inserted node containing New_Item. The search for
173 -- an existing element works as follows. Hash is called to determine
174 -- New_Item's bucket; if the bucket is non-empty, then Equivalent_Elements
175 -- is called to compare New_Item to the element of each node in that
176 -- bucket. If the bucket is empty, or there were no equivalent elements in
177 -- the bucket, the search "fails" and the New_Item is inserted in the set
178 -- (and Inserted returns True); otherwise, the search "succeeds" (and
179 -- Inserted returns False).
181 procedure Insert (Container : in out Set; New_Item : Element_Type);
182 -- Attempts to insert New_Item into the set, performing the usual insertion
183 -- search (which involves calling both Hash and Equivalent_Elements); if
184 -- the search succeeds (New_Item is equivalent to an element already in the
185 -- set, and so was not inserted), then this operation raises
186 -- Constraint_Error. (This version of Insert is similar to Replace, but
187 -- having the opposite exception behavior. It is intended for use when you
188 -- want to assert that the item is not already in the set.)
190 procedure Include (Container : in out Set; New_Item : Element_Type);
191 -- Attempts to insert New_Item into the set. If an element equivalent to
192 -- New_Item is already in the set (the insertion search succeeded, and
193 -- hence New_Item was not inserted), then the value of New_Item is assigned
194 -- to the existing element. (This insertion operation only raises an
195 -- exception if cursor tampering occurs. It is intended for use when you
196 -- want to insert the item in the set, and you don't care whether an
197 -- equivalent element is already present.)
199 procedure Replace (Container : in out Set; New_Item : Element_Type);
200 -- Searches for New_Item in the set; if the search fails (because an
201 -- equivalent element was not in the set), then it raises
202 -- Constraint_Error. Otherwise, the existing element is assigned the value
203 -- New_Item. (This is similar to Insert, but with the opposite exception
204 -- behavior. It is intended for use when you want to assert that the item
205 -- is already in the set.)
207 procedure Exclude (Container : in out Set; Item : Element_Type);
208 -- Searches for Item in the set, and if found, removes its node from the
209 -- set and then deallocates it. The search works as follows. The operation
210 -- calls Hash to determine the item's bucket; if the bucket is not empty,
211 -- it calls Equivalent_Elements to compare Item to the element of each node
212 -- in the bucket. (This is the deletion analog of Include. It is intended
213 -- for use when you want to remove the item from the set, but don't care
214 -- whether the item is already in the set.)
216 procedure Delete (Container : in out Set; Item : Element_Type);
217 -- Searches for Item in the set (which involves calling both Hash and
218 -- Equivalent_Elements). If the search fails, then the operation raises
219 -- Constraint_Error. Otherwise it removes the node from the set and then
220 -- deallocates it. (This is the deletion analog of non-conditional
221 -- Insert. It is intended for use when you want to assert that the item is
222 -- already in the set.)
224 procedure Delete (Container : in out Set; Position : in out Cursor);
225 -- Removes the node designated by Position from the set, and then
226 -- deallocates the node. The operation calls Hash to determine the bucket,
227 -- and then compares Position to each node in the bucket until there's a
228 -- match (it does not call Equivalent_Elements).
230 procedure Union (Target : in out Set; Source : Set);
231 -- The operation first calls Reserve_Capacity if the current capacity is
232 -- less than the sum of the lengths of Source and Target. It then iterates
233 -- over the Source set, and conditionally inserts each element into Target.
235 function Union (Left, Right : Set) return Set;
236 -- The operation first copies the Left set to the result, and then iterates
237 -- over the Right set to conditionally insert each element into the result.
239 function "or" (Left, Right : Set) return Set renames Union;
241 procedure Intersection (Target : in out Set; Source : Set);
242 -- Iterates over the Target set (calling First and Next), calling Find to
243 -- determine whether the element is in Source. If an equivalent element is
244 -- not found in Source, the element is deleted from Target.
246 function Intersection (Left, Right : Set) return Set;
247 -- Iterates over the Left set, calling Find to determine whether the
248 -- element is in Right. If an equivalent element is found, it is inserted
249 -- into the result set.
251 function "and" (Left, Right : Set) return Set renames Intersection;
253 procedure Difference (Target : in out Set; Source : Set);
254 -- Iterates over the Source (calling First and Next), calling Find to
255 -- determine whether the element is in Target. If an equivalent element is
256 -- found, it is deleted from Target.
258 function Difference (Left, Right : Set) return Set;
259 -- Iterates over the Left set, calling Find to determine whether the
260 -- element is in the Right set. If an equivalent element is not found, the
261 -- element is inserted into the result set.
263 function "-" (Left, Right : Set) return Set renames Difference;
265 procedure Symmetric_Difference (Target : in out Set; Source : Set);
266 -- The operation first calls Reserve_Capacity if the current capacity is
267 -- less than the sum of the lengths of Source and Target. It then iterates
268 -- over the Source set, searching for the element in Target (calling Hash
269 -- and Equivalent_Elements). If an equivalent element is found, it is
270 -- removed from Target; otherwise it is inserted into Target.
272 function Symmetric_Difference (Left, Right : Set) return Set;
273 -- The operation first iterates over the Left set. It calls Find to
274 -- determine whether the element is in the Right set. If no equivalent
275 -- element is found, the element from Left is inserted into the result. The
276 -- operation then iterates over the Right set, to determine whether the
277 -- element is in the Left set. If no equivalent element is found, the Right
278 -- element is inserted into the result.
280 function "xor" (Left, Right : Set) return Set
281 renames Symmetric_Difference;
283 function Overlap (Left, Right : Set) return Boolean;
284 -- Iterates over the Left set (calling First and Next), calling Find to
285 -- determine whether the element is in the Right set. If an equivalent
286 -- element is found, the operation immediately returns True. The operation
287 -- returns False if the iteration over Left terminates without finding any
288 -- equivalent element in Right.
290 function Is_Subset (Subset : Set; Of_Set : Set) return Boolean;
291 -- Iterates over Subset (calling First and Next), calling Find to determine
292 -- whether the element is in Of_Set. If no equivalent element is found in
293 -- Of_Set, the operation immediately returns False. The operation returns
294 -- True if the iteration over Subset terminates without finding an element
295 -- not in Of_Set (that is, every element in Subset is equivalent to an
296 -- element in Of_Set).
298 function First (Container : Set) return Cursor;
299 -- Returns a cursor that designates the first non-empty bucket, by
300 -- searching from the beginning of the buckets array.
302 function Next (Position : Cursor) return Cursor;
303 -- Returns a cursor that designates the node that follows the current one
304 -- designated by Position. If Position designates the last node in its
305 -- bucket, the operation calls Hash to compute the index of this bucket,
306 -- and searches the buckets array for the first non-empty bucket, starting
307 -- from that index; otherwise, it simply follows the link to the next node
308 -- in the same bucket.
310 procedure Next (Position : in out Cursor);
311 -- Equivalent to Position := Next (Position)
313 function Find (Container : Set; Item : Element_Type) return Cursor;
314 -- Searches for Item in the set. Find calls Hash to determine the item's
315 -- bucket; if the bucket is not empty, it calls Equivalent_Elements to
316 -- compare Item to each element in the bucket. If the search succeeds, Find
317 -- returns a cursor designating the node containing the equivalent element;
318 -- otherwise, it returns No_Element.
320 function Contains (Container : Set; Item : Element_Type) return Boolean;
321 -- Equivalent to Find (Container, Item) /= No_Element
323 function Equivalent_Elements (Left, Right : Cursor) return Boolean;
324 -- Returns the result of calling Equivalent_Elements with the elements of
325 -- the nodes designated by cursors Left and Right.
327 function Equivalent_Elements
329 Right : Element_Type) return Boolean;
330 -- Returns the result of calling Equivalent_Elements with element of the
331 -- node designated by Left and element Right.
333 function Equivalent_Elements
334 (Left : Element_Type;
335 Right : Cursor) return Boolean;
336 -- Returns the result of calling Equivalent_Elements with element Left and
337 -- the element of the node designated by Right.
341 Process : not null access procedure (Position : Cursor));
342 -- Calls Process for each node in the set
344 function Iterate (Container : Set)
345 return Set_Iterator_Interfaces.Forward_Iterator'Class;
348 type Key_Type (<>) is private;
350 with function Key (Element : Element_Type) return Key_Type;
352 with function Hash (Key : Key_Type) return Hash_Type;
354 with function Equivalent_Keys (Left, Right : Key_Type) return Boolean;
356 package Generic_Keys is
358 function Key (Position : Cursor) return Key_Type;
359 -- Applies generic formal operation Key to the element of the node
360 -- designated by Position.
362 function Element (Container : Set; Key : Key_Type) return Element_Type;
363 -- Searches (as per the key-based Find) for the node containing Key, and
364 -- returns the associated element.
367 (Container : in out Set;
369 New_Item : Element_Type);
370 -- Searches (as per the key-based Find) for the node containing Key, and
371 -- then replaces the element of that node (as per the element-based
374 procedure Exclude (Container : in out Set; Key : Key_Type);
375 -- Searches for Key in the set, and if found, removes its node from the
376 -- set and then deallocates it. The search works by first calling Hash
377 -- (on Key) to determine the bucket; if the bucket is not empty, it
378 -- calls Equivalent_Keys to compare parameter Key to the value of
379 -- generic formal operation Key applied to element of each node in the
382 procedure Delete (Container : in out Set; Key : Key_Type);
383 -- Deletes the node containing Key as per Exclude, with the difference
384 -- that Constraint_Error is raised if Key is not found.
386 function Find (Container : Set; Key : Key_Type) return Cursor;
387 -- Searches for the node containing Key, and returns a cursor
388 -- designating the node. The search works by first calling Hash (on Key)
389 -- to determine the bucket. If the bucket is not empty, the search
390 -- compares Key to the element of each node in the bucket, and returns
391 -- the matching node. The comparison itself works by applying the
392 -- generic formal Key operation to the element of the node, and then
393 -- calling generic formal operation Equivalent_Keys.
395 function Contains (Container : Set; Key : Key_Type) return Boolean;
396 -- Equivalent to Find (Container, Key) /= No_Element
398 procedure Update_Element_Preserving_Key
399 (Container : in out Set;
401 Process : not null access
402 procedure (Element : in out Element_Type));
403 -- Calls Process with the element of the node designated by Position,
404 -- but with the restriction that the key-value of the element is not
405 -- modified. The operation first makes a copy of the value returned by
406 -- applying generic formal operation Key on the element of the node, and
407 -- then calls Process with the element. The operation verifies that the
408 -- key-part has not been modified by calling generic formal operation
409 -- Equivalent_Keys to compare the saved key-value to the value returned
410 -- by applying generic formal operation Key to the post-Process value of
411 -- element. If the key values compare equal then the operation
412 -- completes. Otherwise, the node is removed from the map and
413 -- Program_Error is raised.
415 type Reference_Type (Element : not null access Element_Type) is private
416 with Implicit_Dereference => Element;
418 function Reference_Preserving_Key
419 (Container : aliased in out Set;
420 Position : Cursor) return Reference_Type;
422 function Constant_Reference
423 (Container : aliased Set;
424 Key : Key_Type) return Constant_Reference_Type;
426 function Reference_Preserving_Key
427 (Container : aliased in out Set;
428 Key : Key_Type) return Reference_Type;
431 type Reference_Type (Element : not null access Element_Type)
437 (Stream : not null access Root_Stream_Type'Class;
438 Item : out Reference_Type);
440 for Reference_Type'Read use Read;
443 (Stream : not null access Root_Stream_Type'Class;
444 Item : Reference_Type);
446 for Reference_Type'Write use Write;
450 pragma Inline (Next);
453 type Node_Access is access Node_Type;
455 type Element_Access is access Element_Type;
457 type Node_Type is limited record
458 Element : Element_Access;
463 new Hash_Tables.Generic_Hash_Table_Types (Node_Type, Node_Access);
465 type Set is new Ada.Finalization.Controlled with record
466 HT : HT_Types.Hash_Table_Type;
469 overriding procedure Adjust (Container : in out Set);
471 overriding procedure Finalize (Container : in out Set);
474 use Ada.Finalization;
477 type Set_Access is access all Set;
478 for Set_Access'Storage_Size use 0;
480 type Cursor is record
481 Container : Set_Access;
486 (Stream : not null access Root_Stream_Type'Class;
489 for Cursor'Write use Write;
492 (Stream : not null access Root_Stream_Type'Class;
495 for Cursor'Read use Read;
497 No_Element : constant Cursor := (Container => null, Node => null);
500 (Stream : not null access Root_Stream_Type'Class;
503 for Set'Write use Write;
506 (Stream : not null access Root_Stream_Type'Class;
507 Container : out Set);
509 for Set'Read use Read;
511 type Constant_Reference_Type
512 (Element : not null access constant Element_Type) is null record;
515 (Stream : not null access Root_Stream_Type'Class;
516 Item : out Constant_Reference_Type);
518 for Constant_Reference_Type'Read use Read;
521 (Stream : not null access Root_Stream_Type'Class;
522 Item : Constant_Reference_Type);
524 for Constant_Reference_Type'Write use Write;
526 Empty_Set : constant Set := (Controlled with HT => (null, 0, 0, 0));
528 end Ada.Containers.Indefinite_Hashed_Sets;