gcc/ada/a-cforse.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT LIBRARY COMPONENTS                          --
   4 --                                                                          --
   5 --   A D A . C O N T A I N E R S . F O R M A L _ O R D E R E D _ S E T S    --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2004-2013, 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
  32 --  This spec is derived from package Ada.Containers.Bounded_Ordered_Sets in
  33 --  the Ada 2012 RM. The modifications are meant to facilitate formal proofs by
  34 --  making it easier to express properties, and by making the specification of
  35 --  this unit compatible with SPARK 2014. Note that the API of this unit may be
  36 --  subject to incompatible changes as SPARK 2014 evolves.
  37
  38 --  The modifications are:
  39
  40 --    A parameter for the container is added to every function reading the
  41 --    content of a container: Key, Element, Next, Query_Element, Previous,
  42 --    Has_Element, Iterate, Reverse_Iterate. This change is motivated by the
  43 --    need to have cursors which are valid on different containers (typically
  44 --    a container C and its previous version C'Old) for expressing properties,
  45 --    which is not possible if cursors encapsulate an access to the underlying
  46 --    container. The operators "<" and ">" that could not be modified that way
  47 --    have been removed.
  48
  49 --    There are three new functions:
  50
  51 --      function Strict_Equal (Left, Right : Set) return Boolean;
  52 --      function Left  (Container : Set; Position : Cursor) return Set;
  53 --      function Right (Container : Set; Position : Cursor) return Set;
  54
  55 --    See detailed specifications for these subprograms
  56
  57 private with Ada.Containers.Red_Black_Trees;
  58
  59 generic
  60    type Element_Type is private;
  61
  62    with function "<" (Left, Right : Element_Type) return Boolean is <>;
  63    with function "=" (Left, Right : Element_Type) return Boolean is <>;
  64
  65 package Ada.Containers.Formal_Ordered_Sets is
  66    pragma Pure;
  67
  68    function Equivalent_Elements (Left, Right : Element_Type) return Boolean;
  69
  70    type Set (Capacity : Count_Type) is private;
  71    pragma Preelaborable_Initialization (Set);
  72
  73    type Cursor is private;
  74    pragma Preelaborable_Initialization (Cursor);
  75
  76    Empty_Set : constant Set;
  77
  78    No_Element : constant Cursor;
  79
  80    function "=" (Left, Right : Set) return Boolean;
  81
  82    function Equivalent_Sets (Left, Right : Set) return Boolean;
  83
  84    function To_Set (New_Item : Element_Type) return Set;
  85
  86    function Length (Container : Set) return Count_Type;
  87
  88    function Is_Empty (Container : Set) return Boolean;
  89
  90    procedure Clear (Container : in out Set);
  91
  92    procedure Assign (Target : in out Set; Source : Set) with
  93      Pre => Target.Capacity >= Length (Source);
  94
  95    function Copy (Source : Set; Capacity : Count_Type := 0) return Set with
  96      Pre => Capacity >= Source.Capacity;
  97
  98    function Element
  99      (Container : Set;
 100       Position  : Cursor) return Element_Type
 101    with
 102      Pre => Has_Element (Container, Position);
 103
 104    procedure Replace_Element
 105      (Container : in out Set;
 106       Position  : Cursor;
 107       New_Item  : Element_Type)
 108    with
 109      Pre => Has_Element (Container, Position);
 110
 111    procedure Move (Target : in out Set; Source : in out Set) with
 112      Pre => Target.Capacity >= Length (Source);
 113
 114    procedure Insert
 115      (Container : in out Set;
 116       New_Item  : Element_Type;
 117       Position  : out Cursor;
 118       Inserted  : out Boolean)
 119    with
 120      Pre => Length (Container) < Container.Capacity;
 121
 122    procedure Insert
 123      (Container : in out Set;
 124       New_Item  : Element_Type)
 125    with
 126      Pre => Length (Container) < Container.Capacity
 127               and then (not Contains (Container, New_Item));
 128
 129    procedure Include
 130      (Container : in out Set;
 131       New_Item  : Element_Type)
 132    with
 133      Pre => Length (Container) < Container.Capacity;
 134
 135    procedure Replace
 136      (Container : in out Set;
 137       New_Item  : Element_Type)
 138    with
 139      Pre => Contains (Container, New_Item);
 140
 141    procedure Exclude
 142      (Container : in out Set;
 143       Item      : Element_Type);
 144
 145    procedure Delete
 146      (Container : in out Set;
 147       Item      : Element_Type)
 148    with
 149      Pre => Contains (Container, Item);
 150
 151    procedure Delete
 152      (Container : in out Set;
 153       Position  : in out Cursor)
 154    with
 155      Pre => Has_Element (Container, Position);
 156
 157    procedure Delete_First (Container : in out Set);
 158
 159    procedure Delete_Last (Container : in out Set);
 160
 161    procedure Union (Target : in out Set; Source : Set) with
 162      Pre => Length (Target) + Length (Source) -
 163               Length (Intersection (Target, Source)) <= Target.Capacity;
 164
 165    function Union (Left, Right : Set) return Set;
 166
 167    function "or" (Left, Right : Set) return Set renames Union;
 168
 169    procedure Intersection (Target : in out Set; Source : Set);
 170
 171    function Intersection (Left, Right : Set) return Set;
 172
 173    function "and" (Left, Right : Set) return Set renames Intersection;
 174
 175    procedure Difference (Target : in out Set; Source : Set);
 176
 177    function Difference (Left, Right : Set) return Set;
 178
 179    function "-" (Left, Right : Set) return Set renames Difference;
 180
 181    procedure Symmetric_Difference (Target : in out Set; Source : Set);
 182
 183    function Symmetric_Difference (Left, Right : Set) return Set;
 184
 185    function "xor" (Left, Right : Set) return Set renames Symmetric_Difference;
 186
 187    function Overlap (Left, Right : Set) return Boolean;
 188
 189    function Is_Subset (Subset : Set; Of_Set : Set) return Boolean;
 190
 191    function First (Container : Set) return Cursor;
 192
 193    function First_Element (Container : Set) return Element_Type with
 194      Pre => not Is_Empty (Container);
 195
 196    function Last (Container : Set) return Cursor;
 197
 198    function Last_Element (Container : Set) return Element_Type with
 199      Pre => not Is_Empty (Container);
 200
 201    function Next (Container : Set; Position : Cursor) return Cursor with
 202      Pre => Has_Element (Container, Position) or else Position = No_Element;
 203
 204    procedure Next (Container : Set; Position : in out Cursor) with
 205      Pre => Has_Element (Container, Position) or else Position = No_Element;
 206
 207    function Previous (Container : Set; Position : Cursor) return Cursor with
 208      Pre => Has_Element (Container, Position) or else Position = No_Element;
 209
 210    procedure Previous (Container : Set; Position : in out Cursor) with
 211      Pre => Has_Element (Container, Position) or else Position = No_Element;
 212
 213    function Find (Container : Set; Item : Element_Type) return Cursor;
 214
 215    function Floor (Container : Set; Item : Element_Type) return Cursor;
 216
 217    function Ceiling (Container : Set; Item : Element_Type) return Cursor;
 218
 219    function Contains (Container : Set; Item : Element_Type) return Boolean;
 220
 221    function Has_Element (Container : Set; Position : Cursor) return Boolean;
 222
 223    generic
 224       type Key_Type (<>) is private;
 225
 226       with function Key (Element : Element_Type) return Key_Type;
 227
 228       with function "<" (Left, Right : Key_Type) return Boolean is <>;
 229
 230    package Generic_Keys is
 231
 232       function Equivalent_Keys (Left, Right : Key_Type) return Boolean;
 233
 234       function Key (Container : Set; Position : Cursor) return Key_Type;
 235
 236       function Element (Container : Set; Key : Key_Type) return Element_Type;
 237
 238       procedure Replace
 239         (Container : in out Set;
 240          Key       : Key_Type;
 241          New_Item  : Element_Type);
 242
 243       procedure Exclude (Container : in out Set; Key : Key_Type);
 244
 245       procedure Delete (Container : in out Set; Key : Key_Type);
 246
 247       function Find (Container : Set; Key : Key_Type) return Cursor;
 248
 249       function Floor (Container : Set; Key : Key_Type) return Cursor;
 250
 251       function Ceiling (Container : Set; Key : Key_Type) return Cursor;
 252
 253       function Contains (Container : Set; Key : Key_Type) return Boolean;
 254
 255    end Generic_Keys;
 256
 257    function Strict_Equal (Left, Right : Set) return Boolean;
 258    --  Strict_Equal returns True if the containers are physically equal, i.e.
 259    --  they are structurally equal (function "=" returns True) and that they
 260    --  have the same set of cursors.
 261
 262    function Left  (Container : Set; Position : Cursor) return Set with
 263      Pre => Has_Element (Container, Position) or else Position = No_Element;
 264    function Right (Container : Set; Position : Cursor) return Set with
 265      Pre => Has_Element (Container, Position) or else Position = No_Element;
 266    --  Left returns a container containing all elements preceding Position
 267    --  (excluded) in Container. Right returns a container containing all
 268    --  elements following Position (included) in Container. These two new
 269    --  functions can be used to express invariant properties in loops which
 270    --  iterate over containers. Left returns the part of the container already
 271    --  scanned and Right the part not scanned yet.
 272
 273 private
 274
 275    pragma Inline (Next);
 276    pragma Inline (Previous);
 277
 278    type Node_Type is record
 279       Has_Element : Boolean := False;
 280       Parent  : Count_Type := 0;
 281       Left    : Count_Type := 0;
 282       Right   : Count_Type := 0;
 283       Color   : Red_Black_Trees.Color_Type;
 284       Element : Element_Type;
 285    end record;
 286
 287    package Tree_Types is
 288      new Red_Black_Trees.Generic_Bounded_Tree_Types (Node_Type);
 289
 290    type Set (Capacity : Count_Type) is
 291      new Tree_Types.Tree_Type (Capacity) with null record;
 292
 293    use Red_Black_Trees;
 294
 295    type Cursor is record
 296       Node : Count_Type;
 297    end record;
 298
 299    No_Element : constant Cursor := (Node => 0);
 300
 301    Empty_Set : constant Set := (Capacity => 0, others => <>);
 302
 303 end Ada.Containers.Formal_Ordered_Sets;