1------------------------------------------------------------------------------ 2-- -- 3-- GNAT LIBRARY COMPONENTS -- 4-- -- 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 _ S E T S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 2004-2014, 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-- 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. -- 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 34with Ada.Iterator_Interfaces; 35 36private with Ada.Containers.Hash_Tables; 37private with Ada.Streams; 38private with Ada.Finalization; use Ada.Finalization; 39 40generic 41 type Element_Type is private; 42 43 with function Hash (Element : Element_Type) return Hash_Type; 44 45 with function Equivalent_Elements 46 (Left, Right : Element_Type) return Boolean; 47 48 with function "=" (Left, Right : Element_Type) return Boolean is <>; 49 50package Ada.Containers.Bounded_Hashed_Sets is 51 pragma Pure; 52 pragma Remote_Types; 53 54 type Set (Capacity : Count_Type; Modulus : Hash_Type) is tagged private 55 with Constant_Indexing => Constant_Reference, 56 Default_Iterator => Iterate, 57 Iterator_Element => Element_Type; 58 59 pragma Preelaborable_Initialization (Set); 60 61 type Cursor is private; 62 pragma Preelaborable_Initialization (Cursor); 63 64 Empty_Set : constant Set; 65 -- Set objects declared without an initialization expression are 66 -- initialized to the value Empty_Set. 67 68 No_Element : constant Cursor; 69 -- Cursor objects declared without an initialization expression are 70 -- initialized to the value No_Element. 71 72 function Has_Element (Position : Cursor) return Boolean; 73 -- Equivalent to Position /= No_Element 74 75 package Set_Iterator_Interfaces is new 76 Ada.Iterator_Interfaces (Cursor, Has_Element); 77 78 function "=" (Left, Right : Set) return Boolean; 79 -- For each element in Left, set equality attempts to find the equal 80 -- element in Right; if a search fails, then set equality immediately 81 -- returns False. The search works by calling Hash to find the bucket in 82 -- the Right set that corresponds to the Left element. If the bucket is 83 -- non-empty, the search calls the generic formal element equality operator 84 -- to compare the element (in Left) to the element of each node in the 85 -- bucket (in Right); the search terminates when a matching node in the 86 -- bucket is found, or the nodes in the bucket are exhausted. (Note that 87 -- element equality is called here, not Equivalent_Elements. Set equality 88 -- is the only operation in which element equality is used. Compare set 89 -- equality to Equivalent_Sets, which does call Equivalent_Elements.) 90 91 function Equivalent_Sets (Left, Right : Set) return Boolean; 92 -- Similar to set equality, with the difference that the element in Left is 93 -- compared to the elements in Right using the generic formal 94 -- Equivalent_Elements operation instead of element equality. 95 96 function To_Set (New_Item : Element_Type) return Set; 97 -- Constructs a singleton set comprising New_Element. To_Set calls Hash to 98 -- determine the bucket for New_Item. 99 100 function Capacity (Container : Set) return Count_Type; 101 -- Returns the current capacity of the set. Capacity is the maximum length 102 -- before which rehashing in guaranteed not to occur. 103 104 procedure Reserve_Capacity (Container : in out Set; Capacity : Count_Type); 105 -- If the value of the Capacity actual parameter is less or equal to 106 -- Container.Capacity, then the operation has no effect. Otherwise it 107 -- raises Capacity_Error (as no expansion of capacity is possible for a 108 -- bounded form). 109 110 function Default_Modulus (Capacity : Count_Type) return Hash_Type; 111 -- Returns a modulus value (hash table size) which is optimal for the 112 -- specified capacity (which corresponds to the maximum number of items). 113 114 function Length (Container : Set) return Count_Type; 115 -- Returns the number of items in the set 116 117 function Is_Empty (Container : Set) return Boolean; 118 -- Equivalent to Length (Container) = 0 119 120 procedure Clear (Container : in out Set); 121 -- Removes all of the items from the set 122 123 function Element (Position : Cursor) return Element_Type; 124 -- Returns the element of the node designated by the cursor 125 126 procedure Replace_Element 127 (Container : in out Set; 128 Position : Cursor; 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 139 -- its new bucket. 140 141 procedure Query_Element 142 (Position : Cursor; 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. 146 147 type Constant_Reference_Type 148 (Element : not null access constant Element_Type) is private 149 with Implicit_Dereference => Element; 150 151 function Constant_Reference 152 (Container : aliased Set; 153 Position : Cursor) return Constant_Reference_Type; 154 155 procedure Assign (Target : in out Set; Source : Set); 156 -- If Target denotes the same object as Source, then the operation has no 157 -- effect. If the Target capacity is less than the Source length, then 158 -- Assign raises Capacity_Error. Otherwise, Assign clears Target and then 159 -- copies the (active) elements from Source to Target. 160 161 function Copy 162 (Source : Set; 163 Capacity : Count_Type := 0; 164 Modulus : Hash_Type := 0) return Set; 165 -- Constructs a new set object whose elements correspond to Source. If the 166 -- Capacity parameter is 0, then the capacity of the result is the same as 167 -- the length of Source. If the Capacity parameter is equal or greater than 168 -- the length of Source, then the capacity of the result is the specified 169 -- value. Otherwise, Copy raises Capacity_Error. If the Modulus parameter 170 -- is 0, then the modulus of the result is the value returned by a call to 171 -- Default_Modulus with the capacity parameter determined as above; 172 -- otherwise the modulus of the result is the specified value. 173 174 procedure Move (Target : in out Set; Source : in out Set); 175 -- Clears Target (if it's not empty), and then moves (not copies) the 176 -- buckets array and nodes from Source to Target. 177 178 procedure Insert 179 (Container : in out Set; 180 New_Item : Element_Type; 181 Position : out Cursor; 182 Inserted : out Boolean); 183 -- Conditionally inserts New_Item into the set. If New_Item is already in 184 -- the set, then Inserted returns False and Position designates the node 185 -- containing the existing element (which is not modified). If New_Item is 186 -- not already in the set, then Inserted returns True and Position 187 -- designates the newly-inserted node containing New_Item. The search for 188 -- an existing element works as follows. Hash is called to determine 189 -- New_Item's bucket; if the bucket is non-empty, then Equivalent_Elements 190 -- is called to compare New_Item to the element of each node in that 191 -- bucket. If the bucket is empty, or there were no equivalent elements in 192 -- the bucket, the search "fails" and the New_Item is inserted in the set 193 -- (and Inserted returns True); otherwise, the search "succeeds" (and 194 -- Inserted returns False). 195 196 procedure Insert (Container : in out Set; New_Item : Element_Type); 197 -- Attempts to insert New_Item into the set, performing the usual insertion 198 -- search (which involves calling both Hash and Equivalent_Elements); if 199 -- the search succeeds (New_Item is equivalent to an element already in the 200 -- set, and so was not inserted), then this operation raises 201 -- Constraint_Error. (This version of Insert is similar to Replace, but 202 -- having the opposite exception behavior. It is intended for use when you 203 -- want to assert that the item is not already in the set.) 204 205 procedure Include (Container : in out Set; New_Item : Element_Type); 206 -- Attempts to insert New_Item into the set. If an element equivalent to 207 -- New_Item is already in the set (the insertion search succeeded, and 208 -- hence New_Item was not inserted), then the value of New_Item is assigned 209 -- to the existing element. (This insertion operation only raises an 210 -- exception if cursor tampering occurs. It is intended for use when you 211 -- want to insert the item in the set, and you don't care whether an 212 -- equivalent element is already present.) 213 214 procedure Replace (Container : in out Set; New_Item : Element_Type); 215 -- Searches for New_Item in the set; if the search fails (because an 216 -- equivalent element was not in the set), then it raises 217 -- Constraint_Error. Otherwise, the existing element is assigned the value 218 -- New_Item. (This is similar to Insert, but with the opposite exception 219 -- behavior. It is intended for use when you want to assert that the item 220 -- is already in the set.) 221 222 procedure Exclude (Container : in out Set; Item : Element_Type); 223 -- Searches for Item in the set, and if found, removes its node from the 224 -- set and then deallocates it. The search works as follows. The operation 225 -- calls Hash to determine the item's bucket; if the bucket is not empty, 226 -- it calls Equivalent_Elements to compare Item to the element of each node 227 -- in the bucket. (This is the deletion analog of Include. It is intended 228 -- for use when you want to remove the item from the set, but don't care 229 -- whether the item is already in the set.) 230 231 procedure Delete (Container : in out Set; Item : Element_Type); 232 -- Searches for Item in the set (which involves calling both Hash and 233 -- Equivalent_Elements). If the search fails, then the operation raises 234 -- Constraint_Error. Otherwise it removes the node from the set and then 235 -- deallocates it. (This is the deletion analog of non-conditional 236 -- Insert. It is intended for use when you want to assert that the item is 237 -- already in the set.) 238 239 procedure Delete (Container : in out Set; Position : in out Cursor); 240 -- Removes the node designated by Position from the set, and then 241 -- deallocates the node. The operation calls Hash to determine the bucket, 242 -- and then compares Position to each node in the bucket until there's a 243 -- match (it does not call Equivalent_Elements). 244 245 procedure Union (Target : in out Set; Source : Set); 246 -- Iterates over the Source set, and conditionally inserts each element 247 -- into Target. 248 249 function Union (Left, Right : Set) return Set; 250 -- The operation first copies the Left set to the result, and then iterates 251 -- over the Right set to conditionally insert each element into the result. 252 253 function "or" (Left, Right : Set) return Set renames Union; 254 255 procedure Intersection (Target : in out Set; Source : Set); 256 -- Iterates over the Target set (calling First and Next), calling Find to 257 -- determine whether the element is in Source. If an equivalent element is 258 -- not found in Source, the element is deleted from Target. 259 260 function Intersection (Left, Right : Set) return Set; 261 -- Iterates over the Left set, calling Find to determine whether the 262 -- element is in Right. If an equivalent element is found, it is inserted 263 -- into the result set. 264 265 function "and" (Left, Right : Set) return Set renames Intersection; 266 267 procedure Difference (Target : in out Set; Source : Set); 268 -- Iterates over the Source (calling First and Next), calling Find to 269 -- determine whether the element is in Target. If an equivalent element is 270 -- found, it is deleted from Target. 271 272 function Difference (Left, Right : Set) return Set; 273 -- Iterates over the Left set, calling Find to determine whether the 274 -- element is in the Right set. If an equivalent element is not found, the 275 -- element is inserted into the result set. 276 277 function "-" (Left, Right : Set) return Set renames Difference; 278 279 procedure Symmetric_Difference (Target : in out Set; Source : Set); 280 -- The operation iterates over the Source set, searching for the element 281 -- in Target (calling Hash and Equivalent_Elements). If an equivalent 282 -- element is found, it is removed from Target; otherwise it is inserted 283 -- into Target. 284 285 function Symmetric_Difference (Left, Right : Set) return Set; 286 -- The operation first iterates over the Left set. It calls Find to 287 -- determine whether the element is in the Right set. If no equivalent 288 -- element is found, the element from Left is inserted into the result. The 289 -- operation then iterates over the Right set, to determine whether the 290 -- element is in the Left set. If no equivalent element is found, the Right 291 -- element is inserted into the result. 292 293 function "xor" (Left, Right : Set) return Set 294 renames Symmetric_Difference; 295 296 function Overlap (Left, Right : Set) return Boolean; 297 -- Iterates over the Left set (calling First and Next), calling Find to 298 -- determine whether the element is in the Right set. If an equivalent 299 -- element is found, the operation immediately returns True. The operation 300 -- returns False if the iteration over Left terminates without finding any 301 -- equivalent element in Right. 302 303 function Is_Subset (Subset : Set; Of_Set : Set) return Boolean; 304 -- Iterates over Subset (calling First and Next), calling Find to determine 305 -- whether the element is in Of_Set. If no equivalent element is found in 306 -- Of_Set, the operation immediately returns False. The operation returns 307 -- True if the iteration over Subset terminates without finding an element 308 -- not in Of_Set (that is, every element in Subset is equivalent to an 309 -- element in Of_Set). 310 311 function First (Container : Set) return Cursor; 312 -- Returns a cursor that designates the first non-empty bucket, by 313 -- searching from the beginning of the buckets array. 314 315 function Next (Position : Cursor) return Cursor; 316 -- Returns a cursor that designates the node that follows the current one 317 -- designated by Position. If Position designates the last node in its 318 -- bucket, the operation calls Hash to compute the index of this bucket, 319 -- and searches the buckets array for the first non-empty bucket, starting 320 -- from that index; otherwise, it simply follows the link to the next node 321 -- in the same bucket. 322 323 procedure Next (Position : in out Cursor); 324 -- Equivalent to Position := Next (Position) 325 326 function Find 327 (Container : Set; 328 Item : Element_Type) return Cursor; 329 -- Searches for Item in the set. Find calls Hash to determine the item's 330 -- bucket; if the bucket is not empty, it calls Equivalent_Elements to 331 -- compare Item to each element in the bucket. If the search succeeds, Find 332 -- returns a cursor designating the node containing the equivalent element; 333 -- otherwise, it returns No_Element. 334 335 function Contains (Container : Set; Item : Element_Type) return Boolean; 336 -- Equivalent to Find (Container, Item) /= No_Element 337 338 function Equivalent_Elements (Left, Right : Cursor) return Boolean; 339 -- Returns the result of calling Equivalent_Elements with the elements of 340 -- the nodes designated by cursors Left and Right. 341 342 function Equivalent_Elements 343 (Left : Cursor; 344 Right : Element_Type) return Boolean; 345 -- Returns the result of calling Equivalent_Elements with element of the 346 -- node designated by Left and element Right. 347 348 function Equivalent_Elements 349 (Left : Element_Type; 350 Right : Cursor) return Boolean; 351 -- Returns the result of calling Equivalent_Elements with element Left and 352 -- the element of the node designated by Right. 353 354 procedure Iterate 355 (Container : Set; 356 Process : not null access procedure (Position : Cursor)); 357 -- Calls Process for each node in the set 358 359 function Iterate 360 (Container : Set) 361 return Set_Iterator_Interfaces.Forward_Iterator'Class; 362 363 generic 364 type Key_Type (<>) is private; 365 366 with function Key (Element : Element_Type) return Key_Type; 367 368 with function Hash (Key : Key_Type) return Hash_Type; 369 370 with function Equivalent_Keys (Left, Right : Key_Type) return Boolean; 371 372 package Generic_Keys is 373 374 function Key (Position : Cursor) return Key_Type; 375 -- Applies generic formal operation Key to the element of the node 376 -- designated by Position. 377 378 function Element (Container : Set; Key : Key_Type) return Element_Type; 379 -- Searches (as per the key-based Find) for the node containing Key, and 380 -- returns the associated element. 381 382 procedure Replace 383 (Container : in out Set; 384 Key : Key_Type; 385 New_Item : Element_Type); 386 -- Searches (as per the key-based Find) for the node containing Key, and 387 -- then replaces the element of that node (as per the element-based 388 -- Replace_Element). 389 390 procedure Exclude (Container : in out Set; Key : Key_Type); 391 -- Searches for Key in the set, and if found, removes its node from the 392 -- set and then deallocates it. The search works by first calling Hash 393 -- (on Key) to determine the bucket; if the bucket is not empty, it 394 -- calls Equivalent_Keys to compare parameter Key to the value of 395 -- generic formal operation Key applied to element of each node in the 396 -- bucket. 397 398 procedure Delete (Container : in out Set; Key : Key_Type); 399 -- Deletes the node containing Key as per Exclude, with the difference 400 -- that Constraint_Error is raised if Key is not found. 401 402 function Find (Container : Set; Key : Key_Type) return Cursor; 403 -- Searches for the node containing Key, and returns a cursor 404 -- designating the node. The search works by first calling Hash (on Key) 405 -- to determine the bucket. If the bucket is not empty, the search 406 -- compares Key to the element of each node in the bucket, and returns 407 -- the matching node. The comparison itself works by applying the 408 -- generic formal Key operation to the element of the node, and then 409 -- calling generic formal operation Equivalent_Keys. 410 411 function Contains (Container : Set; Key : Key_Type) return Boolean; 412 -- Equivalent to Find (Container, Key) /= No_Element 413 414 procedure Update_Element_Preserving_Key 415 (Container : in out Set; 416 Position : Cursor; 417 Process : not null access 418 procedure (Element : in out Element_Type)); 419 -- Calls Process with the element of the node designated by Position, 420 -- but with the restriction that the key-value of the element is not 421 -- modified. The operation first makes a copy of the value returned by 422 -- applying generic formal operation Key on the element of the node, and 423 -- then calls Process with the element. The operation verifies that the 424 -- key-part has not been modified by calling generic formal operation 425 -- Equivalent_Keys to compare the saved key-value to the value returned 426 -- by applying generic formal operation Key to the post-Process value of 427 -- element. If the key values compare equal then the operation 428 -- completes. Otherwise, the node is removed from the map and 429 -- Program_Error is raised. 430 431 type Reference_Type (Element : not null access Element_Type) is private 432 with Implicit_Dereference => Element; 433 434 function Reference_Preserving_Key 435 (Container : aliased in out Set; 436 Position : Cursor) return Reference_Type; 437 438 function Constant_Reference 439 (Container : aliased Set; 440 Key : Key_Type) return Constant_Reference_Type; 441 442 function Reference_Preserving_Key 443 (Container : aliased in out Set; 444 Key : Key_Type) return Reference_Type; 445 446 private 447 type Set_Access is access all Set; 448 for Set_Access'Storage_Size use 0; 449 450 type Reference_Control_Type is 451 new Ada.Finalization.Controlled with 452 record 453 Container : Set_Access; 454 Index : Hash_Type; 455 Old_Pos : Cursor; 456 Old_Hash : Hash_Type; 457 end record; 458 459 overriding procedure Adjust (Control : in out Reference_Control_Type); 460 pragma Inline (Adjust); 461 462 overriding procedure Finalize (Control : in out Reference_Control_Type); 463 pragma Inline (Finalize); 464 465 type Reference_Type (Element : not null access Element_Type) is record 466 Control : Reference_Control_Type; 467 end record; 468 469 use Ada.Streams; 470 471 procedure Read 472 (Stream : not null access Root_Stream_Type'Class; 473 Item : out Reference_Type); 474 475 for Reference_Type'Read use Read; 476 477 procedure Write 478 (Stream : not null access Root_Stream_Type'Class; 479 Item : Reference_Type); 480 481 for Reference_Type'Write use Write; 482 483 end Generic_Keys; 484 485private 486 pragma Inline (Next); 487 488 type Node_Type is record 489 Element : aliased Element_Type; 490 Next : Count_Type; 491 end record; 492 493 package HT_Types is 494 new Hash_Tables.Generic_Bounded_Hash_Table_Types (Node_Type); 495 496 type Set (Capacity : Count_Type; Modulus : Hash_Type) is 497 new HT_Types.Hash_Table_Type (Capacity, Modulus) with null record; 498 499 use HT_Types; 500 use Ada.Streams; 501 502 procedure Write 503 (Stream : not null access Root_Stream_Type'Class; 504 Container : Set); 505 506 for Set'Write use Write; 507 508 procedure Read 509 (Stream : not null access Root_Stream_Type'Class; 510 Container : out Set); 511 512 for Set'Read use Read; 513 514 type Set_Access is access all Set; 515 for Set_Access'Storage_Size use 0; 516 517 -- Note: If a Cursor object has no explicit initialization expression, 518 -- it must default initialize to the same value as constant No_Element. 519 -- The Node component of type Cursor has scalar type Count_Type, so it 520 -- requires an explicit initialization expression of its own declaration, 521 -- in order for objects of record type Cursor to properly initialize. 522 523 type Cursor is record 524 Container : Set_Access; 525 Node : Count_Type := 0; 526 end record; 527 528 procedure Write 529 (Stream : not null access Root_Stream_Type'Class; 530 Item : Cursor); 531 532 for Cursor'Write use Write; 533 534 procedure Read 535 (Stream : not null access Root_Stream_Type'Class; 536 Item : out Cursor); 537 538 for Cursor'Read use Read; 539 540 type Reference_Control_Type is new Controlled with record 541 Container : Set_Access; 542 end record; 543 544 overriding procedure Adjust (Control : in out Reference_Control_Type); 545 pragma Inline (Adjust); 546 547 overriding procedure Finalize (Control : in out Reference_Control_Type); 548 pragma Inline (Finalize); 549 550 type Constant_Reference_Type 551 (Element : not null access constant Element_Type) is 552 record 553 Control : Reference_Control_Type; 554 end record; 555 556 procedure Read 557 (Stream : not null access Root_Stream_Type'Class; 558 Item : out Constant_Reference_Type); 559 560 for Constant_Reference_Type'Read use Read; 561 562 procedure Write 563 (Stream : not null access Root_Stream_Type'Class; 564 Item : Constant_Reference_Type); 565 566 for Constant_Reference_Type'Write use Write; 567 568 Empty_Set : constant Set := 569 (Hash_Table_Type with Capacity => 0, Modulus => 0); 570 571 No_Element : constant Cursor := (Container => null, Node => 0); 572 573 type Iterator is new Limited_Controlled and 574 Set_Iterator_Interfaces.Forward_Iterator with 575 record 576 Container : Set_Access; 577 end record; 578 579 overriding procedure Finalize (Object : in out Iterator); 580 581 overriding function First (Object : Iterator) return Cursor; 582 583 overriding function Next 584 (Object : Iterator; 585 Position : Cursor) return Cursor; 586 587end Ada.Containers.Bounded_Hashed_Sets; 588