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) 2004-2020, 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; 37with Ada.Containers.Helpers; 38private with Ada.Streams; 39private with Ada.Finalization; 40private with Ada.Strings.Text_Output; 41 42generic 43 type Element_Type is private; 44 45 with function Hash (Element : Element_Type) return Hash_Type; 46 47 with function Equivalent_Elements 48 (Left, Right : Element_Type) return Boolean; 49 50 with function "=" (Left, Right : Element_Type) return Boolean is <>; 51 52package Ada.Containers.Bounded_Hashed_Sets with 53 SPARK_Mode => Off 54is 55 pragma Annotate (CodePeer, Skip_Analysis); 56 pragma Pure; 57 pragma Remote_Types; 58 59 type Set (Capacity : Count_Type; Modulus : Hash_Type) is tagged private 60 with Constant_Indexing => Constant_Reference, 61 Default_Iterator => Iterate, 62 Iterator_Element => Element_Type, 63 Aggregate => (Empty => Empty, 64 Add_Unnamed => Include); 65 66 pragma Preelaborable_Initialization (Set); 67 68 type Cursor is private; 69 pragma Preelaborable_Initialization (Cursor); 70 71 Empty_Set : constant Set; 72 -- Set objects declared without an initialization expression are 73 -- initialized to the value Empty_Set. 74 75 function Empty (Capacity : Count_Type := 10) return Set; 76 77 No_Element : constant Cursor; 78 -- Cursor objects declared without an initialization expression are 79 -- initialized to the value No_Element. 80 81 function Has_Element (Position : Cursor) return Boolean; 82 -- Equivalent to Position /= No_Element 83 84 package Set_Iterator_Interfaces is new 85 Ada.Iterator_Interfaces (Cursor, Has_Element); 86 87 function "=" (Left, Right : Set) return Boolean; 88 -- For each element in Left, set equality attempts to find the equal 89 -- element in Right; if a search fails, then set equality immediately 90 -- returns False. The search works by calling Hash to find the bucket in 91 -- the Right set that corresponds to the Left element. If the bucket is 92 -- non-empty, the search calls the generic formal element equality operator 93 -- to compare the element (in Left) to the element of each node in the 94 -- bucket (in Right); the search terminates when a matching node in the 95 -- bucket is found, or the nodes in the bucket are exhausted. (Note that 96 -- element equality is called here, not Equivalent_Elements. Set equality 97 -- is the only operation in which element equality is used. Compare set 98 -- equality to Equivalent_Sets, which does call Equivalent_Elements.) 99 100 function Equivalent_Sets (Left, Right : Set) return Boolean; 101 -- Similar to set equality, with the difference that the element in Left is 102 -- compared to the elements in Right using the generic formal 103 -- Equivalent_Elements operation instead of element equality. 104 105 function To_Set (New_Item : Element_Type) return Set; 106 -- Constructs a singleton set comprising New_Element. To_Set calls Hash to 107 -- determine the bucket for New_Item. 108 109 function Capacity (Container : Set) return Count_Type; 110 -- Returns the current capacity of the set. Capacity is the maximum length 111 -- before which rehashing in guaranteed not to occur. 112 113 procedure Reserve_Capacity (Container : in out Set; Capacity : Count_Type); 114 -- If the value of the Capacity actual parameter is less or equal to 115 -- Container.Capacity, then the operation has no effect. Otherwise it 116 -- raises Capacity_Error (as no expansion of capacity is possible for a 117 -- bounded form). 118 119 function Default_Modulus (Capacity : Count_Type) return Hash_Type; 120 -- Returns a modulus value (hash table size) which is optimal for the 121 -- specified capacity (which corresponds to the maximum number of items). 122 123 function Length (Container : Set) return Count_Type; 124 -- Returns the number of items in the set 125 126 function Is_Empty (Container : Set) return Boolean; 127 -- Equivalent to Length (Container) = 0 128 129 procedure Clear (Container : in out Set); 130 -- Removes all of the items from the set. This will deallocate all memory 131 -- associated with this set. 132 133 function Element (Position : Cursor) return Element_Type; 134 -- Returns the element of the node designated by the cursor 135 136 procedure Replace_Element 137 (Container : in out Set; 138 Position : Cursor; 139 New_Item : Element_Type); 140 -- If New_Item is equivalent (as determined by calling Equivalent_Elements) 141 -- to the element of the node designated by Position, then New_Element is 142 -- assigned to that element. Otherwise, it calls Hash to determine the 143 -- bucket for New_Item. If the bucket is not empty, then it calls 144 -- Equivalent_Elements for each node in that bucket to determine whether 145 -- New_Item is equivalent to an element in that bucket. If 146 -- Equivalent_Elements returns True then Program_Error is raised (because 147 -- an element may appear only once in the set); otherwise, New_Item is 148 -- assigned to the node designated by Position, and the node is moved to 149 -- its new bucket. 150 151 procedure Query_Element 152 (Position : Cursor; 153 Process : not null access procedure (Element : Element_Type)); 154 -- Calls Process with the element (having only a constant view) of the node 155 -- designated by the cursor. 156 157 type Constant_Reference_Type 158 (Element : not null access constant Element_Type) is private 159 with Implicit_Dereference => Element; 160 161 function Constant_Reference 162 (Container : aliased Set; 163 Position : Cursor) return Constant_Reference_Type; 164 165 procedure Assign (Target : in out Set; Source : Set); 166 -- If Target denotes the same object as Source, then the operation has no 167 -- effect. If the Target capacity is less than the Source length, then 168 -- Assign raises Capacity_Error. Otherwise, Assign clears Target and then 169 -- copies the (active) elements from Source to Target. 170 171 function Copy 172 (Source : Set; 173 Capacity : Count_Type := 0; 174 Modulus : Hash_Type := 0) return Set; 175 -- Constructs a new set object whose elements correspond to Source. If the 176 -- Capacity parameter is 0, then the capacity of the result is the same as 177 -- the length of Source. If the Capacity parameter is equal or greater than 178 -- the length of Source, then the capacity of the result is the specified 179 -- value. Otherwise, Copy raises Capacity_Error. If the Modulus parameter 180 -- is 0, then the modulus of the result is the value returned by a call to 181 -- Default_Modulus with the capacity parameter determined as above; 182 -- otherwise the modulus of the result is the specified value. 183 184 procedure Move (Target : in out Set; Source : in out Set); 185 -- Clears Target (if it's not empty), and then moves (not copies) the 186 -- buckets array and nodes from Source to Target. 187 188 procedure Insert 189 (Container : in out Set; 190 New_Item : Element_Type; 191 Position : out Cursor; 192 Inserted : out Boolean); 193 -- Conditionally inserts New_Item into the set. If New_Item is already in 194 -- the set, then Inserted returns False and Position designates the node 195 -- containing the existing element (which is not modified). If New_Item is 196 -- not already in the set, then Inserted returns True and Position 197 -- designates the newly-inserted node containing New_Item. The search for 198 -- an existing element works as follows. Hash is called to determine 199 -- New_Item's bucket; if the bucket is non-empty, then Equivalent_Elements 200 -- is called to compare New_Item to the element of each node in that 201 -- bucket. If the bucket is empty, or there were no equivalent elements in 202 -- the bucket, the search "fails" and the New_Item is inserted in the set 203 -- (and Inserted returns True); otherwise, the search "succeeds" (and 204 -- Inserted returns False). 205 206 procedure Insert (Container : in out Set; New_Item : Element_Type); 207 -- Attempts to insert New_Item into the set, performing the usual insertion 208 -- search (which involves calling both Hash and Equivalent_Elements); if 209 -- the search succeeds (New_Item is equivalent to an element already in the 210 -- set, and so was not inserted), then this operation raises 211 -- Constraint_Error. (This version of Insert is similar to Replace, but 212 -- having the opposite exception behavior. It is intended for use when you 213 -- want to assert that the item is not already in the set.) 214 215 procedure Include (Container : in out Set; New_Item : Element_Type); 216 -- Attempts to insert New_Item into the set. If an element equivalent to 217 -- New_Item is already in the set (the insertion search succeeded, and 218 -- hence New_Item was not inserted), then the value of New_Item is assigned 219 -- to the existing element. (This insertion operation only raises an 220 -- exception if cursor tampering occurs. It is intended for use when you 221 -- want to insert the item in the set, and you don't care whether an 222 -- equivalent element is already present.) 223 224 procedure Replace (Container : in out Set; New_Item : Element_Type); 225 -- Searches for New_Item in the set; if the search fails (because an 226 -- equivalent element was not in the set), then it raises 227 -- Constraint_Error. Otherwise, the existing element is assigned the value 228 -- New_Item. (This is similar to Insert, but with the opposite exception 229 -- behavior. It is intended for use when you want to assert that the item 230 -- is already in the set.) 231 232 procedure Exclude (Container : in out Set; Item : Element_Type); 233 -- Searches for Item in the set, and if found, removes its node from the 234 -- set and then deallocates it. The search works as follows. The operation 235 -- calls Hash to determine the item's bucket; if the bucket is not empty, 236 -- it calls Equivalent_Elements to compare Item to the element of each node 237 -- in the bucket. (This is the deletion analog of Include. It is intended 238 -- for use when you want to remove the item from the set, but don't care 239 -- whether the item is already in the set.) 240 241 procedure Delete (Container : in out Set; Item : Element_Type); 242 -- Searches for Item in the set (which involves calling both Hash and 243 -- Equivalent_Elements). If the search fails, then the operation raises 244 -- Constraint_Error. Otherwise it removes the node from the set and then 245 -- deallocates it. (This is the deletion analog of non-conditional 246 -- Insert. It is intended for use when you want to assert that the item is 247 -- already in the set.) 248 249 procedure Delete (Container : in out Set; Position : in out Cursor); 250 -- Removes the node designated by Position from the set, and then 251 -- deallocates the node. The operation calls Hash to determine the bucket, 252 -- and then compares Position to each node in the bucket until there's a 253 -- match (it does not call Equivalent_Elements). 254 255 procedure Union (Target : in out Set; Source : Set); 256 -- Iterates over the Source set, and conditionally inserts each element 257 -- into Target. 258 259 function Union (Left, Right : Set) return Set; 260 -- The operation first copies the Left set to the result, and then iterates 261 -- over the Right set to conditionally insert each element into the result. 262 263 function "or" (Left, Right : Set) return Set renames Union; 264 265 procedure Intersection (Target : in out Set; Source : Set); 266 -- Iterates over the Target set (calling First and Next), calling Find to 267 -- determine whether the element is in Source. If an equivalent element is 268 -- not found in Source, the element is deleted from Target. 269 270 function Intersection (Left, Right : Set) return Set; 271 -- Iterates over the Left set, calling Find to determine whether the 272 -- element is in Right. If an equivalent element is found, it is inserted 273 -- into the result set. 274 275 function "and" (Left, Right : Set) return Set renames Intersection; 276 277 procedure Difference (Target : in out Set; Source : Set); 278 -- Iterates over the Source (calling First and Next), calling Find to 279 -- determine whether the element is in Target. If an equivalent element is 280 -- found, it is deleted from Target. 281 282 function Difference (Left, Right : Set) return Set; 283 -- Iterates over the Left set, calling Find to determine whether the 284 -- element is in the Right set. If an equivalent element is not found, the 285 -- element is inserted into the result set. 286 287 function "-" (Left, Right : Set) return Set renames Difference; 288 289 procedure Symmetric_Difference (Target : in out Set; Source : Set); 290 -- The operation iterates over the Source set, searching for the element 291 -- in Target (calling Hash and Equivalent_Elements). If an equivalent 292 -- element is found, it is removed from Target; otherwise it is inserted 293 -- into Target. 294 295 function Symmetric_Difference (Left, Right : Set) return Set; 296 -- The operation first iterates over the Left set. It calls Find to 297 -- determine whether the element is in the Right set. If no equivalent 298 -- element is found, the element from Left is inserted into the result. The 299 -- operation then iterates over the Right set, to determine whether the 300 -- element is in the Left set. If no equivalent element is found, the Right 301 -- element is inserted into the result. 302 303 function "xor" (Left, Right : Set) return Set 304 renames Symmetric_Difference; 305 306 function Overlap (Left, Right : Set) return Boolean; 307 -- Iterates over the Left set (calling First and Next), calling Find to 308 -- determine whether the element is in the Right set. If an equivalent 309 -- element is found, the operation immediately returns True. The operation 310 -- returns False if the iteration over Left terminates without finding any 311 -- equivalent element in Right. 312 313 function Is_Subset (Subset : Set; Of_Set : Set) return Boolean; 314 -- Iterates over Subset (calling First and Next), calling Find to determine 315 -- whether the element is in Of_Set. If no equivalent element is found in 316 -- Of_Set, the operation immediately returns False. The operation returns 317 -- True if the iteration over Subset terminates without finding an element 318 -- not in Of_Set (that is, every element in Subset is equivalent to an 319 -- element in Of_Set). 320 321 function First (Container : Set) return Cursor; 322 -- Returns a cursor that designates the first non-empty bucket, by 323 -- searching from the beginning of the buckets array. 324 325 function Next (Position : Cursor) return Cursor; 326 -- Returns a cursor that designates the node that follows the current one 327 -- designated by Position. If Position designates the last node in its 328 -- bucket, the operation calls Hash to compute the index of this bucket, 329 -- and searches the buckets array for the first non-empty bucket, starting 330 -- from that index; otherwise, it simply follows the link to the next node 331 -- in the same bucket. 332 333 procedure Next (Position : in out Cursor); 334 -- Equivalent to Position := Next (Position) 335 336 function Find 337 (Container : Set; 338 Item : Element_Type) return Cursor; 339 -- Searches for Item in the set. Find calls Hash to determine the item's 340 -- bucket; if the bucket is not empty, it calls Equivalent_Elements to 341 -- compare Item to each element in the bucket. If the search succeeds, Find 342 -- returns a cursor designating the node containing the equivalent element; 343 -- otherwise, it returns No_Element. 344 345 function Contains (Container : Set; Item : Element_Type) return Boolean; 346 -- Equivalent to Find (Container, Item) /= No_Element 347 348 function Equivalent_Elements (Left, Right : Cursor) return Boolean; 349 -- Returns the result of calling Equivalent_Elements with the elements of 350 -- the nodes designated by cursors Left and Right. 351 352 function Equivalent_Elements 353 (Left : Cursor; 354 Right : Element_Type) return Boolean; 355 -- Returns the result of calling Equivalent_Elements with element of the 356 -- node designated by Left and element Right. 357 358 function Equivalent_Elements 359 (Left : Element_Type; 360 Right : Cursor) return Boolean; 361 -- Returns the result of calling Equivalent_Elements with element Left and 362 -- the element of the node designated by Right. 363 364 procedure Iterate 365 (Container : Set; 366 Process : not null access procedure (Position : Cursor)); 367 -- Calls Process for each node in the set 368 369 function Iterate 370 (Container : Set) 371 return Set_Iterator_Interfaces.Forward_Iterator'Class; 372 373 generic 374 type Key_Type (<>) is private; 375 376 with function Key (Element : Element_Type) return Key_Type; 377 378 with function Hash (Key : Key_Type) return Hash_Type; 379 380 with function Equivalent_Keys (Left, Right : Key_Type) return Boolean; 381 382 package Generic_Keys is 383 384 function Key (Position : Cursor) return Key_Type; 385 -- Applies generic formal operation Key to the element of the node 386 -- designated by Position. 387 388 function Element (Container : Set; Key : Key_Type) return Element_Type; 389 -- Searches (as per the key-based Find) for the node containing Key, and 390 -- returns the associated element. 391 392 procedure Replace 393 (Container : in out Set; 394 Key : Key_Type; 395 New_Item : Element_Type); 396 -- Searches (as per the key-based Find) for the node containing Key, and 397 -- then replaces the element of that node (as per the element-based 398 -- Replace_Element). 399 400 procedure Exclude (Container : in out Set; Key : Key_Type); 401 -- Searches for Key in the set, and if found, removes its node from the 402 -- set and then deallocates it. The search works by first calling Hash 403 -- (on Key) to determine the bucket; if the bucket is not empty, it 404 -- calls Equivalent_Keys to compare parameter Key to the value of 405 -- generic formal operation Key applied to element of each node in the 406 -- bucket. 407 408 procedure Delete (Container : in out Set; Key : Key_Type); 409 -- Deletes the node containing Key as per Exclude, with the difference 410 -- that Constraint_Error is raised if Key is not found. 411 412 function Find (Container : Set; Key : Key_Type) return Cursor; 413 -- Searches for the node containing Key, and returns a cursor 414 -- designating the node. The search works by first calling Hash (on Key) 415 -- to determine the bucket. If the bucket is not empty, the search 416 -- compares Key to the element of each node in the bucket, and returns 417 -- the matching node. The comparison itself works by applying the 418 -- generic formal Key operation to the element of the node, and then 419 -- calling generic formal operation Equivalent_Keys. 420 421 function Contains (Container : Set; Key : Key_Type) return Boolean; 422 -- Equivalent to Find (Container, Key) /= No_Element 423 424 procedure Update_Element_Preserving_Key 425 (Container : in out Set; 426 Position : Cursor; 427 Process : not null access 428 procedure (Element : in out Element_Type)); 429 -- Calls Process with the element of the node designated by Position, 430 -- but with the restriction that the key-value of the element is not 431 -- modified. The operation first makes a copy of the value returned by 432 -- applying generic formal operation Key on the element of the node, and 433 -- then calls Process with the element. The operation verifies that the 434 -- key-part has not been modified by calling generic formal operation 435 -- Equivalent_Keys to compare the saved key-value to the value returned 436 -- by applying generic formal operation Key to the post-Process value of 437 -- element. If the key values compare equal then the operation 438 -- completes. Otherwise, the node is removed from the map and 439 -- Program_Error is raised. 440 441 type Reference_Type (Element : not null access Element_Type) is private 442 with Implicit_Dereference => Element; 443 444 function Reference_Preserving_Key 445 (Container : aliased in out Set; 446 Position : Cursor) return Reference_Type; 447 448 function Constant_Reference 449 (Container : aliased Set; 450 Key : Key_Type) return Constant_Reference_Type; 451 452 function Reference_Preserving_Key 453 (Container : aliased in out Set; 454 Key : Key_Type) return Reference_Type; 455 456 private 457 type Set_Access is access all Set; 458 for Set_Access'Storage_Size use 0; 459 460 package Impl is new Helpers.Generic_Implementation; 461 462 type Reference_Control_Type is 463 new Impl.Reference_Control_Type with 464 record 465 Container : Set_Access; 466 Index : Hash_Type; 467 Old_Pos : Cursor; 468 Old_Hash : Hash_Type; 469 end record; 470 471 overriding procedure Finalize (Control : in out Reference_Control_Type); 472 pragma Inline (Finalize); 473 474 type Reference_Type (Element : not null access Element_Type) is record 475 Control : Reference_Control_Type; 476 end record; 477 478 use Ada.Streams; 479 480 procedure Read 481 (Stream : not null access Root_Stream_Type'Class; 482 Item : out Reference_Type); 483 484 for Reference_Type'Read use Read; 485 486 procedure Write 487 (Stream : not null access Root_Stream_Type'Class; 488 Item : Reference_Type); 489 490 for Reference_Type'Write use Write; 491 492 end Generic_Keys; 493 494private 495 pragma Inline (Next); 496 497 type Node_Type is record 498 Element : aliased Element_Type; 499 Next : Count_Type; 500 end record; 501 502 package HT_Types is 503 new Hash_Tables.Generic_Bounded_Hash_Table_Types (Node_Type); 504 505 type Set (Capacity : Count_Type; Modulus : Hash_Type) is 506 new HT_Types.Hash_Table_Type (Capacity, Modulus) 507 with null record with Put_Image => Put_Image; 508 509 procedure Put_Image 510 (S : in out Ada.Strings.Text_Output.Sink'Class; V : Set); 511 512 use HT_Types, HT_Types.Implementation; 513 use Ada.Streams; 514 515 procedure Write 516 (Stream : not null access Root_Stream_Type'Class; 517 Container : Set); 518 519 for Set'Write use Write; 520 521 procedure Read 522 (Stream : not null access Root_Stream_Type'Class; 523 Container : out Set); 524 525 for Set'Read use Read; 526 527 type Set_Access is access all Set; 528 for Set_Access'Storage_Size use 0; 529 530 -- Note: If a Cursor object has no explicit initialization expression, 531 -- it must default initialize to the same value as constant No_Element. 532 -- The Node component of type Cursor has scalar type Count_Type, so it 533 -- requires an explicit initialization expression of its own declaration, 534 -- in order for objects of record type Cursor to properly initialize. 535 536 type Cursor is record 537 Container : Set_Access; 538 Node : Count_Type := 0; 539 end record; 540 541 procedure Write 542 (Stream : not null access Root_Stream_Type'Class; 543 Item : Cursor); 544 545 for Cursor'Write use Write; 546 547 procedure Read 548 (Stream : not null access Root_Stream_Type'Class; 549 Item : out Cursor); 550 551 for Cursor'Read use Read; 552 553 subtype Reference_Control_Type is Implementation.Reference_Control_Type; 554 -- It is necessary to rename this here, so that the compiler can find it 555 556 type Constant_Reference_Type 557 (Element : not null access constant Element_Type) is 558 record 559 Control : Reference_Control_Type := 560 raise Program_Error with "uninitialized reference"; 561 -- The RM says, "The default initialization of an object of 562 -- type Constant_Reference_Type or Reference_Type propagates 563 -- Program_Error." 564 end record; 565 566 procedure Read 567 (Stream : not null access Root_Stream_Type'Class; 568 Item : out Constant_Reference_Type); 569 570 for Constant_Reference_Type'Read use Read; 571 572 procedure Write 573 (Stream : not null access Root_Stream_Type'Class; 574 Item : Constant_Reference_Type); 575 576 for Constant_Reference_Type'Write use Write; 577 578 -- Three operations are used to optimize in the expansion of "for ... of" 579 -- loops: the Next(Cursor) procedure in the visible part, and the following 580 -- Pseudo_Reference and Get_Element_Access functions. See Sem_Ch5 for 581 -- details. 582 583 function Pseudo_Reference 584 (Container : aliased Set'Class) return Reference_Control_Type; 585 pragma Inline (Pseudo_Reference); 586 -- Creates an object of type Reference_Control_Type pointing to the 587 -- container, and increments the Lock. Finalization of this object will 588 -- decrement the Lock. 589 590 type Element_Access is access all Element_Type with 591 Storage_Size => 0; 592 593 function Get_Element_Access 594 (Position : Cursor) return not null Element_Access; 595 -- Returns a pointer to the element designated by Position. 596 597 Empty_Set : constant Set := 598 (Hash_Table_Type with Capacity => 0, Modulus => 0); 599 600 No_Element : constant Cursor := (Container => null, Node => 0); 601 602 type Iterator is new Ada.Finalization.Limited_Controlled and 603 Set_Iterator_Interfaces.Forward_Iterator with 604 record 605 Container : Set_Access; 606 end record 607 with Disable_Controlled => not T_Check; 608 609 overriding procedure Finalize (Object : in out Iterator); 610 611 overriding function First (Object : Iterator) return Cursor; 612 613 overriding function Next 614 (Object : Iterator; 615 Position : Cursor) return Cursor; 616 617end Ada.Containers.Bounded_Hashed_Sets; 618