gcc/ada/a-cfhama.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 _ M A P S     --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2004-2015, 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_Maps 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 --    contents of a container: Key, Element, Next, Query_Element, Has_Element,
  42 --    Iterate, Equivalent_Keys. This change is motivated by the need to have
  43 --    cursors which are valid on different containers (typically a container C
  44 --    and its previous version C'Old) for expressing properties, which is not
  45 --    possible if cursors encapsulate an access to the underlying container.
  46
  47 --    There are four new functions:
  48
  49 --      function Strict_Equal (Left, Right : Map) return Boolean;
  50 --      function Overlap (Left, Right : Map) return Boolean;
  51 --      function First_To_Previous (Container : Map; Current : Cursor)
  52 --         return Map;
  53 --      function Current_To_Last (Container : Map; Current : Cursor)
  54 --         return Map;
  55
  56 --    See detailed specifications for these subprograms
  57
  58 private with Ada.Containers.Hash_Tables;
  59
  60 generic
  61    type Key_Type is private;
  62    type Element_Type is private;
  63
  64    with function Hash (Key : Key_Type) return Hash_Type;
  65    with function Equivalent_Keys (Left, Right : Key_Type) return Boolean;
  66    with function "=" (Left, Right : Element_Type) return Boolean is <>;
  67
  68 package Ada.Containers.Formal_Hashed_Maps with
  69   Pure,
  70   SPARK_Mode
  71 is
  72    pragma Annotate (GNATprove, External_Axiomatization);
  73    pragma Annotate (CodePeer, Skip_Analysis);
  74
  75    type Map (Capacity : Count_Type; Modulus : Hash_Type) is private with
  76      Iterable => (First       => First,
  77                   Next        => Next,
  78                   Has_Element => Has_Element,
  79                   Element     => Element),
  80      Default_Initial_Condition => Is_Empty (Map);
  81    pragma Preelaborable_Initialization (Map);
  82
  83    type Cursor is private;
  84    pragma Preelaborable_Initialization (Cursor);
  85
  86    Empty_Map : constant Map;
  87
  88    No_Element : constant Cursor;
  89
  90    function "=" (Left, Right : Map) return Boolean with
  91      Global => null;
  92
  93    function Capacity (Container : Map) return Count_Type with
  94      Global => null;
  95
  96    procedure Reserve_Capacity
  97      (Container : in out Map;
  98       Capacity  : Count_Type)
  99    with
 100      Global => null,
 101      Pre    => Capacity <= Container.Capacity;
 102
 103    function Length (Container : Map) return Count_Type with
 104      Global => null;
 105
 106    function Is_Empty (Container : Map) return Boolean with
 107      Global => null;
 108
 109    procedure Clear (Container : in out Map) with
 110      Global => null;
 111
 112    procedure Assign (Target : in out Map; Source : Map) with
 113      Global => null,
 114      Pre    => Target.Capacity >= Length (Source);
 115
 116    function Copy
 117      (Source   : Map;
 118       Capacity : Count_Type := 0) return Map
 119    with
 120      Global => null,
 121      Pre    => Capacity = 0 or else Capacity >= Source.Capacity;
 122    --  Copy returns a container stricty equal to Source. It must have
 123    --  the same cursors associated with each element. Therefore:
 124    --  - capacity=0 means use container.capacity as capacity of target
 125    --  - the modulus cannot be changed.
 126
 127    function Key (Container : Map; Position : Cursor) return Key_Type with
 128      Global => null,
 129      Pre    => Has_Element (Container, Position);
 130
 131    function Element
 132      (Container : Map;
 133       Position  : Cursor) return Element_Type
 134    with
 135      Global => null,
 136      Pre    => Has_Element (Container, Position);
 137
 138    procedure Replace_Element
 139      (Container : in out Map;
 140       Position  : Cursor;
 141       New_Item  : Element_Type)
 142    with
 143      Global => null,
 144      Pre    => Has_Element (Container, Position);
 145
 146    procedure Move (Target : in out Map; Source : in out Map) with
 147      Global => null,
 148      Pre    => Target.Capacity >= Length (Source);
 149
 150    procedure Insert
 151      (Container : in out Map;
 152       Key       : Key_Type;
 153       New_Item  : Element_Type;
 154       Position  : out Cursor;
 155       Inserted  : out Boolean)
 156    with
 157      Global => null,
 158      Pre    => Length (Container) < Container.Capacity;
 159
 160    procedure Insert
 161      (Container : in out Map;
 162       Key       : Key_Type;
 163       New_Item  : Element_Type)
 164    with
 165      Global => null,
 166      Pre    => Length (Container) < Container.Capacity
 167                  and then (not Contains (Container, Key));
 168
 169    procedure Include
 170      (Container : in out Map;
 171       Key       : Key_Type;
 172       New_Item  : Element_Type)
 173    with
 174      Global => null,
 175      Pre    => Length (Container) < Container.Capacity;
 176
 177    procedure Replace
 178      (Container : in out Map;
 179       Key       : Key_Type;
 180       New_Item  : Element_Type)
 181    with
 182      Global => null,
 183      Pre    => Contains (Container, Key);
 184
 185    procedure Exclude (Container : in out Map; Key : Key_Type) with
 186      Global => null;
 187
 188    procedure Delete (Container : in out Map; Key : Key_Type) with
 189      Global => null,
 190      Pre    => Contains (Container, Key);
 191
 192    procedure Delete (Container : in out Map; Position : in out Cursor) with
 193      Global => null,
 194      Pre    => Has_Element (Container, Position);
 195
 196    function First (Container : Map) return Cursor with
 197      Global => null;
 198
 199    function Next (Container : Map; Position : Cursor) return Cursor with
 200      Global => null,
 201      Pre    => Has_Element (Container, Position) or else Position = No_Element;
 202
 203    procedure Next (Container : Map; Position : in out Cursor) with
 204      Global => null,
 205      Pre    => Has_Element (Container, Position) or else Position = No_Element;
 206
 207    function Find (Container : Map; Key : Key_Type) return Cursor with
 208      Global => null;
 209
 210    function Contains (Container : Map; Key : Key_Type) return Boolean with
 211      Global => null;
 212
 213    function Element (Container : Map; Key : Key_Type) return Element_Type with
 214      Global => null,
 215      Pre    => Contains (Container, Key);
 216
 217    function Has_Element (Container : Map; Position : Cursor) return Boolean
 218    with
 219      Global => null;
 220
 221    function Equivalent_Keys
 222      (Left   : Map;
 223       CLeft  : Cursor;
 224       Right  : Map;
 225       CRight : Cursor) return Boolean
 226    with
 227      Global => null;
 228
 229    function Equivalent_Keys
 230      (Left  : Map;
 231       CLeft : Cursor;
 232       Right : Key_Type) return Boolean
 233    with
 234      Global => null;
 235
 236    function Equivalent_Keys
 237      (Left   : Key_Type;
 238       Right  : Map;
 239       CRight : Cursor) return Boolean
 240    with
 241      Global => null;
 242
 243    function Default_Modulus (Capacity : Count_Type) return Hash_Type with
 244      Global => null;
 245
 246    function Strict_Equal (Left, Right : Map) return Boolean with
 247      Ghost,
 248      Global => null;
 249    --  Strict_Equal returns True if the containers are physically equal, i.e.
 250    --  they are structurally equal (function "=" returns True) and that they
 251    --  have the same set of cursors.
 252
 253    function First_To_Previous (Container : Map; Current : Cursor) return Map
 254    with
 255      Ghost,
 256      Global => null,
 257      Pre    => Has_Element (Container, Current) or else Current = No_Element;
 258
 259    function Current_To_Last (Container : Map; Current : Cursor) return Map
 260    with
 261      Ghost,
 262      Global => null,
 263      Pre    => Has_Element (Container, Current) or else Current = No_Element;
 264    --  First_To_Previous returns a container containing all elements preceding
 265    --  Current (excluded) in Container. Current_To_Last returns a container
 266    --  containing all elements following Current (included) in Container.
 267    --  These two new functions can be used to express invariant properties in
 268    --  loops which iterate over containers. First_To_Previous returns the part
 269    --  of the container already scanned and Current_To_Last the part not
 270    --  scanned yet.
 271
 272    function Overlap (Left, Right : Map) return Boolean with
 273      Global => null;
 274    --  Overlap returns True if the containers have common keys
 275
 276 private
 277    pragma SPARK_Mode (Off);
 278
 279    pragma Inline (Length);
 280    pragma Inline (Is_Empty);
 281    pragma Inline (Clear);
 282    pragma Inline (Key);
 283    pragma Inline (Element);
 284    pragma Inline (Contains);
 285    pragma Inline (Capacity);
 286    pragma Inline (Has_Element);
 287    pragma Inline (Equivalent_Keys);
 288    pragma Inline (Next);
 289
 290    type Node_Type is record
 291       Key         : Key_Type;
 292       Element     : Element_Type;
 293       Next        : Count_Type;
 294       Has_Element : Boolean := False;
 295    end record;
 296
 297    package HT_Types is new
 298      Ada.Containers.Hash_Tables.Generic_Bounded_Hash_Table_Types (Node_Type);
 299
 300    type Map (Capacity : Count_Type; Modulus : Hash_Type) is
 301      new HT_Types.Hash_Table_Type (Capacity, Modulus) with null record;
 302
 303    use HT_Types;
 304
 305    type Cursor is record
 306       Node : Count_Type;
 307    end record;
 308
 309    Empty_Map : constant Map := (Capacity => 0, Modulus => 0, others => <>);
 310
 311    No_Element : constant Cursor := (Node => 0);
 312
 313 end Ada.Containers.Formal_Hashed_Maps;