gcc/ada/libgnat/a-coormu.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT LIBRARY COMPONENTS                          --
   4 --                                                                          --
   5 --     A D A . C O N T A I N E R S . O R D E R E D _ M U L T I S E T S      --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2004-2017, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- This unit was originally developed by Matthew J Heaney.                  --
  28 ------------------------------------------------------------------------------
  29
  30 --  The ordered multiset container is similar to the ordered set, but with the
  31 --  difference that multiple equivalent elements are allowed. It also provides
  32 --  additional operations, to iterate over items that are equivalent.
  33
  34 private with Ada.Containers.Red_Black_Trees;
  35 private with Ada.Finalization;
  36 private with Ada.Streams;
  37 with Ada.Iterator_Interfaces;
  38
  39 generic
  40    type Element_Type is private;
  41
  42    with function "<" (Left, Right : Element_Type) return Boolean is <>;
  43    with function "=" (Left, Right : Element_Type) return Boolean is <>;
  44
  45 package Ada.Containers.Ordered_Multisets is
  46    pragma Annotate (CodePeer, Skip_Analysis);
  47    pragma Preelaborate;
  48    pragma Remote_Types;
  49
  50    function Equivalent_Elements (Left, Right : Element_Type) return Boolean;
  51    --  Returns False if Left is less than Right, or Right is less than Left;
  52    --  otherwise, it returns True.
  53
  54    type Set 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    --  The default value for set objects declared without an explicit
  66    --  initialization expression.
  67
  68    No_Element : constant Cursor;
  69    --  The default value for cursor objects declared without an explicit
  70    --  initialization expression.
  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    --  If Left denotes the same set object as Right, then equality returns
  80    --  True. If the length of Left is different from the length of Right, then
  81    --  it returns False. Otherwise, set equality iterates over Left and Right,
  82    --  comparing the element of Left to the element of Right using the equality
  83    --  operator for elements. If the elements compare False, then the iteration
  84    --  terminates and set equality returns False. Otherwise, if all elements
  85    --  compare True, then set equality returns True.
  86
  87    function Equivalent_Sets (Left, Right : Set) return Boolean;
  88    --  Similar to set equality, but with the difference that elements are
  89    --  compared for equivalence instead of equality.
  90
  91    function To_Set (New_Item : Element_Type) return Set;
  92    --  Constructs a set object with New_Item as its single element
  93
  94    function Length (Container : Set) return Count_Type;
  95    --  Returns the total number of elements in Container
  96
  97    function Is_Empty (Container : Set) return Boolean;
  98    --  Returns True if Container.Length is 0
  99
 100    procedure Clear (Container : in out Set);
 101    --  Deletes all elements from Container
 102
 103    function Element (Position : Cursor) return Element_Type;
 104    --  If Position equals No_Element, then Constraint_Error is raised.
 105    --  Otherwise, function Element returns the element designed by Position.
 106
 107    procedure Replace_Element
 108      (Container : in out Set;
 109       Position  : Cursor;
 110       New_Item  : Element_Type);
 111    --  If Position equals No_Element, then Constraint_Error is raised. If
 112    --  Position is associated with a set different from Container, then
 113    --  Program_Error is raised. If New_Item is equivalent to the element
 114    --  designated by Position, then if Container is locked (element tampering
 115    --  has been attempted), Program_Error is raised; otherwise, the element
 116    --  designated by Position is assigned the value of New_Item. If New_Item is
 117    --  not equivalent to the element designated by Position, then if the
 118    --  container is busy (cursor tampering has been attempted), Program_Error
 119    --  is raised; otherwise, the element designed by Position is assigned the
 120    --  value of New_Item, and the node is moved to its new position (in
 121    --  canonical insertion order).
 122
 123    procedure Query_Element
 124      (Position : Cursor;
 125       Process  : not null access procedure (Element : Element_Type));
 126    --  If Position equals No_Element, then Constraint_Error is
 127    --  raised. Otherwise, it calls Process with the element designated by
 128    --  Position as the parameter. This call locks the container, so attempts to
 129    --  change the value of the element while Process is executing (to "tamper
 130    --  with elements") will raise Program_Error.
 131
 132    type Constant_Reference_Type
 133      (Element : not null access constant Element_Type) is private
 134         with Implicit_Dereference => Element;
 135
 136    function Constant_Reference
 137      (Container : aliased Set;
 138       Position  : Cursor) return Constant_Reference_Type;
 139    pragma Inline (Constant_Reference);
 140
 141    procedure Assign (Target : in out Set; Source : Set);
 142
 143    function Copy (Source : Set) return Set;
 144
 145    procedure Move (Target : in out Set; Source : in out Set);
 146    --  If Target denotes the same object as Source, the operation does
 147    --  nothing. If either Target or Source is busy (cursor tampering is
 148    --  attempted), then it raises Program_Error. Otherwise, Target is cleared,
 149    --  and the nodes from Source are moved (not copied) to Target (so Source
 150    --  becomes empty).
 151
 152    procedure Insert
 153      (Container : in out Set;
 154       New_Item  : Element_Type;
 155       Position  : out Cursor);
 156    --  Insert adds New_Item to Container, and returns cursor Position
 157    --  designating the newly inserted node. The node is inserted after any
 158    --  existing elements less than or equivalent to New_Item (and before any
 159    --  elements greater than New_Item). Note that the issue of where the new
 160    --  node is inserted relative to equivalent elements does not arise for
 161    --  unique-key containers, since in that case the insertion would simply
 162    --  fail. For a multiple-key container (the case here), insertion always
 163    --  succeeds, and is defined such that the new item is positioned after any
 164    --  equivalent elements already in the container.
 165
 166    procedure Insert
 167      (Container : in out Set;
 168       New_Item  : Element_Type);
 169    --  Inserts New_Item in Container, but does not return a cursor designating
 170    --  the newly-inserted node.
 171
 172 --  TODO: include Replace too???
 173 --
 174 --     procedure Replace
 175 --       (Container : in out Set;
 176 --        New_Item  : Element_Type);
 177
 178    procedure Exclude
 179      (Container : in out Set;
 180       Item      : Element_Type);
 181    --  Deletes from Container all of the elements equivalent to Item
 182
 183    procedure Delete
 184      (Container : in out Set;
 185       Item      : Element_Type);
 186    --  Deletes from Container all of the elements equivalent to Item. If there
 187    --  are no elements equivalent to Item, then it raises Constraint_Error.
 188
 189    procedure Delete
 190      (Container : in out Set;
 191       Position  : in out Cursor);
 192    --  If Position equals No_Element, then Constraint_Error is raised. If
 193    --  Position is associated with a set different from Container, then
 194    --  Program_Error is raised. Otherwise, the node designated by Position is
 195    --  removed from Container, and Position is set to No_Element.
 196
 197    procedure Delete_First (Container : in out Set);
 198    --  Removes the first node from Container
 199
 200    procedure Delete_Last (Container : in out Set);
 201    --  Removes the last node from Container
 202
 203    procedure Union (Target : in out Set; Source : Set);
 204    --  If Target is busy (cursor tampering is attempted), the Program_Error is
 205    --  raised. Otherwise, it inserts each element of Source into
 206    --  Target. Elements are inserted in the canonical order for multisets, such
 207    --  that the elements from Source are inserted after equivalent elements
 208    --  already in Target.
 209
 210    function Union (Left, Right : Set) return Set;
 211    --  Returns a set comprising the all elements from Left and all of the
 212    --  elements from Right. The elements from Right follow the equivalent
 213    --  elements from Left.
 214
 215    function "or" (Left, Right : Set) return Set renames Union;
 216
 217    procedure Intersection (Target : in out Set; Source : Set);
 218    --  If Target denotes the same object as Source, the operation does
 219    --  nothing. If Target is busy (cursor tampering is attempted),
 220    --  Program_Error is raised. Otherwise, the elements in Target having no
 221    --  equivalent element in Source are deleted from Target.
 222
 223    function Intersection (Left, Right : Set) return Set;
 224    --  If Left denotes the same object as Right, then the function returns a
 225    --  copy of Left. Otherwise, it returns a set comprising the equivalent
 226    --  elements from both Left and Right. Items are inserted in the result set
 227    --  in canonical order, such that the elements from Left precede the
 228    --  equivalent elements from Right.
 229
 230    function "and" (Left, Right : Set) return Set renames Intersection;
 231
 232    procedure Difference (Target : in out Set; Source : Set);
 233    --  If Target is busy (cursor tampering is attempted), then Program_Error is
 234    --  raised. Otherwise, the elements in Target that are equivalent to
 235    --  elements in Source are deleted from Target.
 236
 237    function Difference (Left, Right : Set) return Set;
 238    --  Returns a set comprising the elements from Left that have no equivalent
 239    --  element in Right.
 240
 241    function "-" (Left, Right : Set) return Set renames Difference;
 242
 243    procedure Symmetric_Difference (Target : in out Set; Source : Set);
 244    --  If Target is busy, then Program_Error is raised. Otherwise, the elements
 245    --  in Target equivalent to elements in Source are deleted from Target, and
 246    --  the elements in Source not equivalent to elements in Target are inserted
 247    --  into Target.
 248
 249    function Symmetric_Difference (Left, Right : Set) return Set;
 250    --  Returns a set comprising the union of the elements from Target having no
 251    --  equivalent in Source, and the elements of Source having no equivalent in
 252    --  Target.
 253
 254    function "xor" (Left, Right : Set) return Set renames Symmetric_Difference;
 255
 256    function Overlap (Left, Right : Set) return Boolean;
 257    --  Returns True if Left contains an element equivalent to an element of
 258    --  Right.
 259
 260    function Is_Subset (Subset : Set; Of_Set : Set) return Boolean;
 261    --  Returns True if every element in Subset has an equivalent element in
 262    --  Of_Set.
 263
 264    function First (Container : Set) return Cursor;
 265    --  If Container is empty, the function returns No_Element. Otherwise, it
 266    --  returns a cursor designating the smallest element.
 267
 268    function First_Element (Container : Set) return Element_Type;
 269    --  Equivalent to Element (First (Container))
 270
 271    function Last (Container : Set) return Cursor;
 272    --  If Container is empty, the function returns No_Element. Otherwise, it
 273    --  returns a cursor designating the largest element.
 274
 275    function Last_Element (Container : Set) return Element_Type;
 276    --  Equivalent to Element (Last (Container))
 277
 278    function Next (Position : Cursor) return Cursor;
 279    --  If Position equals No_Element or Last (Container), the function returns
 280    --  No_Element. Otherwise, it returns a cursor designating the node that
 281    --  immediately follows (as per the insertion order) the node designated by
 282    --  Position.
 283
 284    procedure Next (Position : in out Cursor);
 285    --  Equivalent to Position := Next (Position)
 286
 287    function Previous (Position : Cursor) return Cursor;
 288    --  If Position equals No_Element or First (Container), the function returns
 289    --  No_Element. Otherwise, it returns a cursor designating the node that
 290    --  immediately precedes (as per the insertion order) the node designated by
 291    --  Position.
 292
 293    procedure Previous (Position : in out Cursor);
 294    --  Equivalent to Position := Previous (Position)
 295
 296    function Find (Container : Set; Item : Element_Type) return Cursor;
 297    --  Returns a cursor designating the first element in Container equivalent
 298    --  to Item. If there is no equivalent element, it returns No_Element.
 299
 300    function Floor (Container : Set; Item : Element_Type) return Cursor;
 301    --  If Container is empty, the function returns No_Element. If Item is
 302    --  equivalent to elements in Container, it returns a cursor designating the
 303    --  first equivalent element. Otherwise, it returns a cursor designating the
 304    --  largest element less than Item, or No_Element if all elements are
 305    --  greater than Item.
 306
 307    function Ceiling (Container : Set; Item : Element_Type) return Cursor;
 308    --  If Container is empty, the function returns No_Element. If Item is
 309    --  equivalent to elements of Container, it returns a cursor designating the
 310    --  last equivalent element. Otherwise, it returns a cursor designating the
 311    --  smallest element greater than Item, or No_Element if all elements are
 312    --  less than Item.
 313
 314    function Contains (Container : Set; Item : Element_Type) return Boolean;
 315    --  Equivalent to Container.Find (Item) /= No_Element
 316
 317    function "<" (Left, Right : Cursor) return Boolean;
 318    --  Equivalent to Element (Left) < Element (Right)
 319
 320    function ">" (Left, Right : Cursor) return Boolean;
 321    --  Equivalent to Element (Right) < Element (Left)
 322
 323    function "<" (Left : Cursor; Right : Element_Type) return Boolean;
 324    --  Equivalent to Element (Left) < Right
 325
 326    function ">" (Left : Cursor; Right : Element_Type) return Boolean;
 327    --  Equivalent to Right < Element (Left)
 328
 329    function "<" (Left : Element_Type; Right : Cursor) return Boolean;
 330    --  Equivalent to Left < Element (Right)
 331
 332    function ">" (Left : Element_Type; Right : Cursor) return Boolean;
 333    --  Equivalent to Element (Right) < Left
 334
 335    procedure Iterate
 336      (Container : Set;
 337       Process   : not null access procedure (Position : Cursor));
 338    --  Calls Process with a cursor designating each element of Container, in
 339    --  order from Container.First to Container.Last.
 340
 341    procedure Reverse_Iterate
 342      (Container : Set;
 343       Process   : not null access procedure (Position : Cursor));
 344    --  Calls Process with a cursor designating each element of Container, in
 345    --  order from Container.Last to Container.First.
 346
 347    procedure Iterate
 348      (Container : Set;
 349       Item      : Element_Type;
 350       Process   : not null access procedure (Position : Cursor));
 351    --  Call Process with a cursor designating each element equivalent to Item,
 352    --  in order from Container.Floor (Item) to Container.Ceiling (Item).
 353
 354    procedure Reverse_Iterate
 355      (Container : Set;
 356       Item      : Element_Type;
 357       Process   : not null access procedure (Position : Cursor));
 358    --  Call Process with a cursor designating each element equivalent to Item,
 359    --  in order from Container.Ceiling (Item) to Container.Floor (Item).
 360
 361    function Iterate
 362      (Container : Set)
 363       return Set_Iterator_Interfaces.Reversible_Iterator'class;
 364
 365    function Iterate
 366      (Container : Set;
 367       Start     : Cursor)
 368       return Set_Iterator_Interfaces.Reversible_Iterator'class;
 369
 370    generic
 371       type Key_Type (<>) is private;
 372
 373       with function Key (Element : Element_Type) return Key_Type;
 374
 375       with function "<" (Left, Right : Key_Type) return Boolean is <>;
 376
 377    package Generic_Keys is
 378
 379       function Equivalent_Keys (Left, Right : Key_Type) return Boolean;
 380       --  Returns False if Left is less than Right, or Right is less than Left;
 381       --  otherwise, it returns True.
 382
 383       function Key (Position : Cursor) return Key_Type;
 384       --  Equivalent to Key (Element (Position))
 385
 386       function Element (Container : Set; Key : Key_Type) return Element_Type;
 387       --  Equivalent to Element (Find (Container, Key))
 388
 389       procedure Exclude (Container : in out Set; Key : Key_Type);
 390       --  Deletes from Container any elements whose key is equivalent to Key
 391
 392       procedure Delete (Container : in out Set; Key : Key_Type);
 393       --  Deletes from Container any elements whose key is equivalent to
 394       --  Key. If there are no such elements, then it raises Constraint_Error.
 395
 396       function Find (Container : Set; Key : Key_Type) return Cursor;
 397       --  Returns a cursor designating the first element in Container whose key
 398       --  is equivalent to Key. If there is no equivalent element, it returns
 399       --  No_Element.
 400
 401       function Floor (Container : Set; Key : Key_Type) return Cursor;
 402       --  If Container is empty, the function returns No_Element. If Item is
 403       --  equivalent to the keys of elements in Container, it returns a cursor
 404       --  designating the first such element. Otherwise, it returns a cursor
 405       --  designating the largest element whose key is less than Item, or
 406       --  No_Element if all keys are greater than Item.
 407
 408       function Ceiling (Container : Set; Key : Key_Type) return Cursor;
 409       --  If Container is empty, the function returns No_Element. If Item is
 410       --  equivalent to the keys of elements of Container, it returns a cursor
 411       --  designating the last such element. Otherwise, it returns a cursor
 412       --  designating the smallest element whose key is greater than Item, or
 413       --  No_Element if all keys are less than Item.
 414
 415       function Contains (Container : Set; Key : Key_Type) return Boolean;
 416       --  Equivalent to Find (Container, Key) /= No_Element
 417
 418       procedure Update_Element  -- Update_Element_Preserving_Key ???
 419         (Container : in out Set;
 420          Position  : Cursor;
 421          Process   : not null access
 422                        procedure (Element : in out Element_Type));
 423       --  If Position equals No_Element, then Constraint_Error is raised. If
 424       --  Position is associated with a set object different from Container,
 425       --  then Program_Error is raised. Otherwise, it makes a copy of the key
 426       --  of the element designated by Position, and then calls Process with
 427       --  the element as the parameter. Update_Element then compares the key
 428       --  value obtained before calling Process to the key value obtained from
 429       --  the element after calling Process. If the keys are equivalent then
 430       --  the operation terminates. If Container is busy (cursor tampering has
 431       --  been attempted), then Program_Error is raised. Otherwise, the node
 432       --  is moved to its new position (in canonical order).
 433
 434       procedure Iterate
 435         (Container : Set;
 436          Key       : Key_Type;
 437          Process   : not null access procedure (Position : Cursor));
 438       --  Call Process with a cursor designating each element equivalent to
 439       --  Key, in order from Floor (Container, Key) to
 440       --  Ceiling (Container, Key).
 441
 442       procedure Reverse_Iterate
 443         (Container : Set;
 444          Key       : Key_Type;
 445          Process   : not null access procedure (Position : Cursor));
 446       --  Call Process with a cursor designating each element equivalent to
 447       --  Key, in order from Ceiling (Container, Key) to
 448       --  Floor (Container, Key).
 449
 450    end Generic_Keys;
 451
 452 private
 453
 454    pragma Inline (Next);
 455    pragma Inline (Previous);
 456
 457    type Node_Type;
 458    type Node_Access is access Node_Type;
 459
 460    type Node_Type is limited record
 461       Parent  : Node_Access;
 462       Left    : Node_Access;
 463       Right   : Node_Access;
 464       Color   : Red_Black_Trees.Color_Type := Red_Black_Trees.Red;
 465       Element : Element_Type;
 466    end record;
 467
 468    package Tree_Types is
 469      new Red_Black_Trees.Generic_Tree_Types (Node_Type, Node_Access);
 470
 471    type Set is new Ada.Finalization.Controlled with record
 472       Tree : Tree_Types.Tree_Type;
 473    end record;
 474
 475    overriding procedure Adjust (Container : in out Set);
 476
 477    overriding procedure Finalize (Container : in out Set) renames Clear;
 478
 479    use Red_Black_Trees;
 480    use Tree_Types, Tree_Types.Implementation;
 481    use Ada.Finalization;
 482    use Ada.Streams;
 483
 484    type Set_Access is access all Set;
 485    for Set_Access'Storage_Size use 0;
 486
 487    --  In all predefined libraries the following type is controlled, for proper
 488    --  management of tampering checks. For performance reason we omit this
 489    --  machinery for multisets, which are used in a number of our tools.
 490
 491    type Reference_Control_Type is record
 492       Container : Set_Access;
 493    end record;
 494
 495    type Constant_Reference_Type
 496      (Element : not null access constant Element_Type) is record
 497       Control : Reference_Control_Type :=
 498         raise Program_Error with "uninitialized reference";
 499       --  The RM says, "The default initialization of an object of
 500       --  type Constant_Reference_Type or Reference_Type propagates
 501       --  Program_Error."
 502    end record;
 503
 504    type Cursor is record
 505       Container : Set_Access;
 506       Node      : Node_Access;
 507    end record;
 508
 509    procedure Write
 510      (Stream : not null access Root_Stream_Type'Class;
 511       Item   : Cursor);
 512
 513    for Cursor'Write use Write;
 514
 515    procedure Read
 516      (Stream : not null access Root_Stream_Type'Class;
 517       Item   : out Cursor);
 518
 519    for Cursor'Read use Read;
 520
 521    No_Element : constant Cursor := Cursor'(null, null);
 522
 523    procedure Write
 524      (Stream    : not null access Root_Stream_Type'Class;
 525       Container : Set);
 526
 527    for Set'Write use Write;
 528
 529    procedure Read
 530      (Stream    : not null access Root_Stream_Type'Class;
 531       Container : out Set);
 532
 533    for Set'Read use Read;
 534
 535    procedure Read
 536      (Stream : not null access Root_Stream_Type'Class;
 537       Item   : out Constant_Reference_Type);
 538
 539    for Constant_Reference_Type'Read use Read;
 540
 541    procedure Write
 542      (Stream : not null access Root_Stream_Type'Class;
 543       Item   : Constant_Reference_Type);
 544
 545    for Constant_Reference_Type'Write use Write;
 546
 547    Empty_Set : constant Set := (Controlled with others => <>);
 548
 549    type Iterator is new Limited_Controlled and
 550      Set_Iterator_Interfaces.Reversible_Iterator with
 551    record
 552       Container : Set_Access;
 553       Node      : Node_Access;
 554    end record
 555      with Disable_Controlled => not T_Check;
 556
 557    overriding procedure Finalize (Object : in out Iterator);
 558
 559    overriding function First (Object : Iterator) return Cursor;
 560    overriding function Last  (Object : Iterator) return Cursor;
 561
 562    overriding function Next
 563      (Object   : Iterator;
 564       Position : Cursor) return Cursor;
 565
 566    overriding function Previous
 567      (Object   : Iterator;
 568       Position : Cursor) return Cursor;
 569
 570 end Ada.Containers.Ordered_Multisets;