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