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 Annotate (GNATprove, External_Axiomatization);
  67    pragma Pure;
  68
  69    function Equivalent_Elements (Left, Right : Element_Type) return Boolean;
  70
  71    type Set (Capacity : Count_Type) is private;
  72    pragma Preelaborable_Initialization (Set);
  73
  74    type Cursor is private;
  75    pragma Preelaborable_Initialization (Cursor);
  76
  77    Empty_Set : constant Set;
  78
  79    No_Element : constant Cursor;
  80
  81    function "=" (Left, Right : Set) return Boolean;
  82
  83    function Equivalent_Sets (Left, Right : Set) return Boolean;
  84
  85    function To_Set (New_Item : Element_Type) return Set;
  86
  87    function Length (Container : Set) return Count_Type;
  88
  89    function Is_Empty (Container : Set) return Boolean;
  90
  91    procedure Clear (Container : in out Set);
  92
  93    procedure Assign (Target : in out Set; Source : Set) with
  94      Pre => Target.Capacity >= Length (Source);
  95
  96    function Copy (Source : Set; Capacity : Count_Type := 0) return Set with
  97      Pre => Capacity = 0 or else Capacity >= Source.Capacity;
  98
  99    function Element
 100      (Container : Set;
 101       Position  : Cursor) return Element_Type
 102    with
 103      Pre => Has_Element (Container, Position);
 104
 105    procedure Replace_Element
 106      (Container : in out Set;
 107       Position  : Cursor;
 108       New_Item  : Element_Type)
 109    with
 110      Pre => Has_Element (Container, Position);
 111
 112    procedure Move (Target : in out Set; Source : in out Set) with
 113      Pre => Target.Capacity >= Length (Source);
 114
 115    procedure Insert
 116      (Container : in out Set;
 117       New_Item  : Element_Type;
 118       Position  : out Cursor;
 119       Inserted  : out Boolean)
 120    with
 121      Pre => Length (Container) < Container.Capacity;
 122
 123    procedure Insert
 124      (Container : in out Set;
 125       New_Item  : Element_Type)
 126    with
 127      Pre => Length (Container) < Container.Capacity
 128               and then (not Contains (Container, New_Item));
 129
 130    procedure Include
 131      (Container : in out Set;
 132       New_Item  : Element_Type)
 133    with
 134      Pre => Length (Container) < Container.Capacity;
 135
 136    procedure Replace
 137      (Container : in out Set;
 138       New_Item  : Element_Type)
 139    with
 140      Pre => Contains (Container, New_Item);
 141
 142    procedure Exclude
 143      (Container : in out Set;
 144       Item      : Element_Type);
 145
 146    procedure Delete
 147      (Container : in out Set;
 148       Item      : Element_Type)
 149    with
 150      Pre => Contains (Container, Item);
 151
 152    procedure Delete
 153      (Container : in out Set;
 154       Position  : in out Cursor)
 155    with
 156      Pre => Has_Element (Container, Position);
 157
 158    procedure Delete_First (Container : in out Set);
 159
 160    procedure Delete_Last (Container : in out Set);
 161
 162    procedure Union (Target : in out Set; Source : Set) with
 163      Pre => Length (Target) + Length (Source) -
 164               Length (Intersection (Target, Source)) <= Target.Capacity;
 165
 166    function Union (Left, Right : Set) return Set;
 167
 168    function "or" (Left, Right : Set) return Set renames Union;
 169
 170    procedure Intersection (Target : in out Set; Source : Set);
 171
 172    function Intersection (Left, Right : Set) return Set;
 173
 174    function "and" (Left, Right : Set) return Set renames Intersection;
 175
 176    procedure Difference (Target : in out Set; Source : Set);
 177
 178    function Difference (Left, Right : Set) return Set;
 179
 180    function "-" (Left, Right : Set) return Set renames Difference;
 181
 182    procedure Symmetric_Difference (Target : in out Set; Source : Set);
 183
 184    function Symmetric_Difference (Left, Right : Set) return Set;
 185
 186    function "xor" (Left, Right : Set) return Set renames Symmetric_Difference;
 187
 188    function Overlap (Left, Right : Set) return Boolean;
 189
 190    function Is_Subset (Subset : Set; Of_Set : Set) return Boolean;
 191
 192    function First (Container : Set) return Cursor;
 193
 194    function First_Element (Container : Set) return Element_Type with
 195      Pre => not Is_Empty (Container);
 196
 197    function Last (Container : Set) return Cursor;
 198
 199    function Last_Element (Container : Set) return Element_Type with
 200      Pre => not Is_Empty (Container);
 201
 202    function Next (Container : Set; Position : Cursor) return Cursor with
 203      Pre => Has_Element (Container, Position) or else Position = No_Element;
 204
 205    procedure Next (Container : Set; Position : in out Cursor) with
 206      Pre => Has_Element (Container, Position) or else Position = No_Element;
 207
 208    function Previous (Container : Set; Position : Cursor) return Cursor with
 209      Pre => Has_Element (Container, Position) or else Position = No_Element;
 210
 211    procedure Previous (Container : Set; Position : in out Cursor) with
 212      Pre => Has_Element (Container, Position) or else Position = No_Element;
 213
 214    function Find (Container : Set; Item : Element_Type) return Cursor;
 215
 216    function Floor (Container : Set; Item : Element_Type) return Cursor;
 217
 218    function Ceiling (Container : Set; Item : Element_Type) return Cursor;
 219
 220    function Contains (Container : Set; Item : Element_Type) return Boolean;
 221
 222    function Has_Element (Container : Set; Position : Cursor) return Boolean;
 223
 224    generic
 225       type Key_Type (<>) is private;
 226
 227       with function Key (Element : Element_Type) return Key_Type;
 228
 229       with function "<" (Left, Right : Key_Type) return Boolean is <>;
 230
 231    package Generic_Keys is
 232
 233       function Equivalent_Keys (Left, Right : Key_Type) return Boolean;
 234
 235       function Key (Container : Set; Position : Cursor) return Key_Type;
 236
 237       function Element (Container : Set; Key : Key_Type) return Element_Type;
 238
 239       procedure Replace
 240         (Container : in out Set;
 241          Key       : Key_Type;
 242          New_Item  : Element_Type);
 243
 244       procedure Exclude (Container : in out Set; Key : Key_Type);
 245
 246       procedure Delete (Container : in out Set; Key : Key_Type);
 247
 248       function Find (Container : Set; Key : Key_Type) return Cursor;
 249
 250       function Floor (Container : Set; Key : Key_Type) return Cursor;
 251
 252       function Ceiling (Container : Set; Key : Key_Type) return Cursor;
 253
 254       function Contains (Container : Set; Key : Key_Type) return Boolean;
 255
 256    end Generic_Keys;
 257
 258    function Strict_Equal (Left, Right : Set) return Boolean;
 259    --  Strict_Equal returns True if the containers are physically equal, i.e.
 260    --  they are structurally equal (function "=" returns True) and that they
 261    --  have the same set of cursors.
 262
 263    function Left  (Container : Set; Position : Cursor) return Set with
 264      Pre => Has_Element (Container, Position) or else Position = No_Element;
 265    function Right (Container : Set; Position : Cursor) return Set with
 266      Pre => Has_Element (Container, Position) or else Position = No_Element;
 267    --  Left returns a container containing all elements preceding Position
 268    --  (excluded) in Container. Right returns a container containing all
 269    --  elements following Position (included) in Container. These two new
 270    --  functions can be used to express invariant properties in loops which
 271    --  iterate over containers. Left returns the part of the container already
 272    --  scanned and Right the part not scanned yet.
 273
 274 private
 275
 276    pragma Inline (Next);
 277    pragma Inline (Previous);
 278
 279    type Node_Type is record
 280       Has_Element : Boolean := False;
 281       Parent  : Count_Type := 0;
 282       Left    : Count_Type := 0;
 283       Right   : Count_Type := 0;
 284       Color   : Red_Black_Trees.Color_Type;
 285       Element : Element_Type;
 286    end record;
 287
 288    package Tree_Types is
 289      new Red_Black_Trees.Generic_Bounded_Tree_Types (Node_Type);
 290
 291    type Set (Capacity : Count_Type) is
 292      new Tree_Types.Tree_Type (Capacity) with null record;
 293
 294    use Red_Black_Trees;
 295
 296    type Cursor is record
 297       Node : Count_Type;
 298    end record;
 299
 300    No_Element : constant Cursor := (Node => 0);
 301
 302    Empty_Set : constant Set := (Capacity => 0, others => <>);
 303
 304 end Ada.Containers.Formal_Ordered_Sets;