gcc/ada/a-cfhase.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 _ H A S H 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_Hashed_Sets in the
  33 --  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: Element, Next, Query_Element, Has_Element, Key,
  42 --    Iterate, Equivalent_Elements. This change is motivated by the need to
  43 --    have cursors which are valid on different containers (typically a
  44 --    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.
  47
  48 --    There are three new functions:
  49
  50 --      function Strict_Equal (Left, Right : Set) return Boolean;
  51 --      function Left  (Container : Set; Position : Cursor) return Set;
  52 --      function Right (Container : Set; Position : Cursor) return Set;
  53
  54 --    See detailed specifications for these subprograms
  55
  56 private with Ada.Containers.Hash_Tables;
  57
  58 generic
  59    type Element_Type is private;
  60
  61    with function Hash (Element : Element_Type) return Hash_Type;
  62
  63    with function Equivalent_Elements (Left, Right : Element_Type)
  64                                       return Boolean;
  65
  66    with function "=" (Left, Right : Element_Type) return Boolean is <>;
  67
  68 package Ada.Containers.Formal_Hashed_Sets is
  69    pragma Annotate (GNATprove, External_Axiomatization);
  70    pragma Pure;
  71
  72    type Set (Capacity : Count_Type; Modulus : Hash_Type) is private;
  73    pragma Preelaborable_Initialization (Set);
  74
  75    type Cursor is private;
  76    pragma Preelaborable_Initialization (Cursor);
  77
  78    Empty_Set : constant Set;
  79
  80    No_Element : constant Cursor;
  81
  82    function "=" (Left, Right : Set) return Boolean;
  83
  84    function Equivalent_Sets (Left, Right : Set) return Boolean;
  85
  86    function To_Set (New_Item : Element_Type) return Set;
  87
  88    function Capacity (Container : Set) return Count_Type;
  89
  90    procedure Reserve_Capacity
  91      (Container : in out Set;
  92       Capacity  : Count_Type)
  93    with
  94      Pre => Capacity <= Container.Capacity;
  95
  96    function Length (Container : Set) return Count_Type;
  97
  98    function Is_Empty (Container : Set) return Boolean;
  99
 100    procedure Clear (Container : in out Set);
 101
 102    procedure Assign (Target : in out Set; Source : Set) with
 103      Pre => Target.Capacity >= Length (Source);
 104
 105    function Copy
 106      (Source   : Set;
 107       Capacity : Count_Type := 0) return Set
 108    with
 109      Pre => Capacity = 0 or else Capacity >= Source.Capacity;
 110
 111    function Element
 112      (Container : Set;
 113       Position  : Cursor) return Element_Type
 114    with
 115      Pre => Has_Element (Container, Position);
 116
 117    procedure Replace_Element
 118      (Container : in out Set;
 119       Position  : Cursor;
 120       New_Item  : Element_Type)
 121    with
 122      Pre => Has_Element (Container, Position);
 123
 124    procedure Move (Target : in out Set; Source : in out Set) with
 125      Pre => Target.Capacity >= Length (Source);
 126
 127    procedure Insert
 128      (Container : in out Set;
 129       New_Item  : Element_Type;
 130       Position  : out Cursor;
 131       Inserted  : out Boolean)
 132    with
 133      Pre => Length (Container) < Container.Capacity;
 134
 135    procedure Insert  (Container : in out Set; New_Item : Element_Type) with
 136      Pre => Length (Container) < Container.Capacity
 137               and then (not Contains (Container, New_Item));
 138
 139    procedure Include (Container : in out Set; New_Item : Element_Type) with
 140      Pre => Length (Container) < Container.Capacity;
 141
 142    procedure Replace (Container : in out Set; New_Item : Element_Type) with
 143      Pre => Contains (Container, New_Item);
 144
 145    procedure Exclude (Container : in out Set; Item     : Element_Type);
 146
 147    procedure Delete  (Container : in out Set; Item     : Element_Type) with
 148      Pre => Contains (Container, Item);
 149
 150    procedure Delete (Container : in out Set; Position  : in out Cursor) with
 151      Pre => Has_Element (Container, Position);
 152
 153    procedure Union (Target : in out Set; Source : Set) with
 154      Pre => Length (Target) + Length (Source) -
 155               Length (Intersection (Target, Source)) <= Target.Capacity;
 156
 157    function Union (Left, Right : Set) return Set;
 158
 159    function "or" (Left, Right : Set) return Set renames Union;
 160
 161    procedure Intersection (Target : in out Set; Source : Set);
 162
 163    function Intersection (Left, Right : Set) return Set;
 164
 165    function "and" (Left, Right : Set) return Set renames Intersection;
 166
 167    procedure Difference (Target : in out Set; Source : Set);
 168
 169    function Difference (Left, Right : Set) return Set;
 170
 171    function "-" (Left, Right : Set) return Set renames Difference;
 172
 173    procedure Symmetric_Difference (Target : in out Set; Source : Set);
 174
 175    function Symmetric_Difference (Left, Right : Set) return Set;
 176
 177    function "xor" (Left, Right : Set) return Set
 178      renames Symmetric_Difference;
 179
 180    function Overlap (Left, Right : Set) return Boolean;
 181
 182    function Is_Subset (Subset : Set; Of_Set : Set) return Boolean;
 183
 184    function First (Container : Set) return Cursor;
 185
 186    function Next (Container : Set; Position : Cursor) return Cursor with
 187      Pre => Has_Element (Container, Position) or else Position = No_Element;
 188
 189    procedure Next (Container : Set; Position : in out Cursor) with
 190      Pre => Has_Element (Container, Position) or else Position = No_Element;
 191
 192    function Find
 193      (Container : Set;
 194       Item      : Element_Type) return Cursor;
 195
 196    function Contains (Container : Set; Item : Element_Type) return Boolean;
 197
 198    function Has_Element (Container : Set; Position : Cursor) return Boolean;
 199
 200    function Equivalent_Elements (Left  : Set; CLeft : Cursor;
 201                                  Right : Set; CRight : Cursor) return Boolean;
 202
 203    function Equivalent_Elements
 204      (Left  : Set; CLeft : Cursor;
 205       Right : Element_Type) return Boolean;
 206
 207    function Equivalent_Elements
 208      (Left  : Element_Type;
 209       Right : Set; CRight : Cursor) return Boolean;
 210
 211    function Default_Modulus (Capacity : Count_Type) return Hash_Type;
 212
 213    generic
 214       type Key_Type (<>) is private;
 215
 216       with function Key (Element : Element_Type) return Key_Type;
 217
 218       with function Hash (Key : Key_Type) return Hash_Type;
 219
 220       with function Equivalent_Keys (Left, Right : Key_Type) return Boolean;
 221
 222    package Generic_Keys is
 223
 224       function Key (Container : Set; Position : Cursor) return Key_Type;
 225
 226       function Element (Container : Set; Key : Key_Type) return Element_Type;
 227
 228       procedure Replace
 229         (Container : in out Set;
 230          Key       : Key_Type;
 231          New_Item  : Element_Type);
 232
 233       procedure Exclude (Container : in out Set; Key : Key_Type);
 234
 235       procedure Delete (Container : in out Set; Key : Key_Type);
 236
 237       function Find (Container : Set; Key : Key_Type) return Cursor;
 238
 239       function Contains (Container : Set; Key : Key_Type) return Boolean;
 240
 241    end Generic_Keys;
 242
 243    function Strict_Equal (Left, Right : Set) return Boolean;
 244    --  Strict_Equal returns True if the containers are physically equal, i.e.
 245    --  they are structurally equal (function "=" returns True) and that they
 246    --  have the same set of cursors.
 247
 248    function Left  (Container : Set; Position : Cursor) return Set with
 249      Pre => Has_Element (Container, Position) or else Position = No_Element;
 250    function Right (Container : Set; Position : Cursor) return Set with
 251      Pre => Has_Element (Container, Position) or else Position = No_Element;
 252    --  Left returns a container containing all elements preceding Position
 253    --  (excluded) in Container. Right returns a container containing all
 254    --  elements following Position (included) in Container. These two new
 255    --  functions can be used to express invariant properties in loops which
 256    --  iterate over containers. Left returns the part of the container already
 257    --  scanned and Right the part not scanned yet.
 258
 259 private
 260
 261    pragma Inline (Next);
 262
 263    type Node_Type is
 264       record
 265          Element     : Element_Type;
 266          Next        : Count_Type;
 267          Has_Element : Boolean := False;
 268       end record;
 269
 270    package HT_Types is new
 271      Ada.Containers.Hash_Tables.Generic_Bounded_Hash_Table_Types (Node_Type);
 272
 273    type Set (Capacity : Count_Type; Modulus : Hash_Type) is
 274       new HT_Types.Hash_Table_Type (Capacity, Modulus) with null record;
 275
 276    use HT_Types;
 277
 278    type Cursor is record
 279       Node : Count_Type;
 280    end record;
 281
 282    No_Element : constant Cursor := (Node => 0);
 283
 284    Empty_Set : constant Set := (Capacity => 0, Modulus => 0, others => <>);
 285
 286 end Ada.Containers.Formal_Hashed_Sets;