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 _ V E C T O R 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_Vectors in the Ada
33--  2012 RM. The modifications are meant to facilitate formal proofs by making
34--  it easier to express properties, and by making the specification of this
35--  unit compatible with SPARK 2014. Note that the API of this unit may be
36--  subject to incompatible changes as SPARK 2014 evolves.
37
38generic
39   type Index_Type is range <>;
40   type Element_Type is private;
41
42   with function "=" (Left, Right : Element_Type) return Boolean is <>;
43
44   Bounded : Boolean := True;
45   --  If True, the containers are bounded; the initial capacity is the maximum
46   --  size, and heap allocation will be avoided. If False, the containers can
47   --  grow via heap allocation.
48
49package Ada.Containers.Formal_Vectors with
50  SPARK_Mode
51is
52   pragma Annotate (GNATprove, External_Axiomatization);
53   pragma Annotate (CodePeer, Skip_Analysis);
54
55   subtype Extended_Index is Index_Type'Base
56   range Index_Type'First - 1 ..
57     Index_Type'Min (Index_Type'Base'Last - 1, Index_Type'Last) + 1;
58
59   No_Index : constant Extended_Index := Extended_Index'First;
60
61   subtype Capacity_Range is
62     Count_Type range 0 .. Count_Type (Index_Type'Last - Index_Type'First + 1);
63
64   type Vector (Capacity : Capacity_Range) is limited private with
65     Default_Initial_Condition => Is_Empty (Vector);
66   --  In the bounded case, Capacity is the capacity of the container, which
67   --  never changes. In the unbounded case, Capacity is the initial capacity
68   --  of the container, and operations such as Reserve_Capacity and Append can
69   --  increase the capacity. The capacity never shrinks, except in the case of
70   --  Clear.
71   --
72   --  Note that all objects of type Vector are constrained, including in the
73   --  unbounded case; you can't assign from one object to another if the
74   --  Capacity is different.
75
76   function Empty_Vector return Vector;
77
78   function "=" (Left, Right : Vector) return Boolean with
79     Global => null;
80
81   function To_Vector
82     (New_Item : Element_Type;
83      Length   : Capacity_Range) return Vector
84   with
85     Global => null;
86
87   function Capacity (Container : Vector) return Capacity_Range with
88     Global => null,
89     Post => Capacity'Result >= Container.Capacity;
90
91   procedure Reserve_Capacity
92     (Container : in out Vector;
93      Capacity  : Capacity_Range)
94   with
95     Global => null,
96     Pre    => (if Bounded then Capacity <= Container.Capacity);
97
98   function Length (Container : Vector) return Capacity_Range with
99     Global => null;
100
101   function Is_Empty (Container : Vector) return Boolean with
102     Global => null;
103
104   procedure Clear (Container : in out Vector) with
105     Global => null;
106   --  Note that this reclaims storage in the unbounded case. You need to call
107   --  this before a container goes out of scope in order to avoid storage
108   --  leaks. In addition, "X := ..." can leak unless you Clear(X) first.
109
110   procedure Assign (Target : in out Vector; Source : Vector) with
111     Global => null,
112     Pre    => (if Bounded then Length (Source) <= Target.Capacity);
113
114   function Copy
115     (Source   : Vector;
116      Capacity : Capacity_Range := 0) return Vector
117   with
118     Global => null,
119     Pre    => (if Bounded then (Capacity = 0 or Length (Source) <= Capacity));
120
121   function Element
122     (Container : Vector;
123      Index     : Index_Type) return Element_Type
124   with
125     Global => null,
126     Pre    => Index in First_Index (Container) .. Last_Index (Container);
127
128   procedure Replace_Element
129     (Container : in out Vector;
130      Index     : Index_Type;
131      New_Item  : Element_Type)
132   with
133     Global => null,
134     Pre    => Index in First_Index (Container) .. Last_Index (Container);
135
136   procedure Append
137     (Container : in out Vector;
138      New_Item  : Vector)
139   with
140     Global => null,
141     Pre    => (if Bounded then
142                 Length (Container) + Length (New_Item) <= Container.Capacity);
143
144   procedure Append
145     (Container : in out Vector;
146      New_Item  : Element_Type)
147   with
148     Global => null,
149     Pre    => (if Bounded then
150                  Length (Container) < Container.Capacity);
151
152   procedure Delete_Last
153     (Container : in out Vector)
154   with
155     Global => null;
156
157   procedure Reverse_Elements (Container : in out Vector) with
158     Global => null;
159
160   procedure Swap (Container : in out Vector; I, J : Index_Type) with
161     Global => null,
162     Pre    => I in First_Index (Container) .. Last_Index (Container)
163      and then J in First_Index (Container) .. Last_Index (Container);
164
165   function First_Index (Container : Vector) return Index_Type with
166     Global => null;
167
168   function First_Element (Container : Vector) return Element_Type with
169     Global => null,
170     Pre    => not Is_Empty (Container);
171
172   function Last_Index (Container : Vector) return Extended_Index with
173     Global => null;
174
175   function Last_Element (Container : Vector) return Element_Type with
176     Global => null,
177     Pre    => not Is_Empty (Container);
178
179   function Find_Index
180     (Container : Vector;
181      Item      : Element_Type;
182      Index     : Index_Type := Index_Type'First) return Extended_Index
183   with
184     Global => null;
185
186   function Reverse_Find_Index
187     (Container : Vector;
188      Item      : Element_Type;
189      Index     : Index_Type := Index_Type'Last) return Extended_Index
190   with
191     Global => null;
192
193   function Contains
194     (Container : Vector;
195      Item      : Element_Type) return Boolean
196   with
197     Global => null;
198
199   function Has_Element
200     (Container : Vector;
201      Position  : Extended_Index) return Boolean
202   with
203     Global => null;
204
205   generic
206      with function "<" (Left, Right : Element_Type) return Boolean is <>;
207   package Generic_Sorting with SPARK_Mode is
208
209      function Is_Sorted (Container : Vector) return Boolean with
210        Global => null;
211
212      procedure Sort (Container : in out Vector) with
213        Global => null;
214
215   end Generic_Sorting;
216
217   function First_To_Previous
218     (Container : Vector;
219      Current   : Index_Type) return Vector
220   with
221     Ghost,
222     Global => null,
223     Pre    => Current in First_Index (Container) .. Last_Index (Container);
224
225   function Current_To_Last
226     (Container : Vector;
227      Current   : Index_Type) return Vector
228   with
229     Ghost,
230     Global => null,
231     Pre    => Current in First_Index (Container) .. Last_Index (Container);
232   --  First_To_Previous returns a container containing all elements preceding
233   --  Current (excluded) in Container. Current_To_Last returns a container
234   --  containing all elements following Current (included) in Container.
235   --  These two new functions can be used to express invariant properties in
236   --  loops which iterate over containers. First_To_Previous returns the part
237   --  of the container already scanned and Current_To_Last the part not
238   --  scanned yet.
239
240private
241   pragma SPARK_Mode (Off);
242
243   pragma Inline (First_Index);
244   pragma Inline (Last_Index);
245   pragma Inline (Element);
246   pragma Inline (First_Element);
247   pragma Inline (Last_Element);
248   pragma Inline (Replace_Element);
249   pragma Inline (Contains);
250
251   subtype Array_Index is Capacity_Range range 1 .. Capacity_Range'Last;
252   type Elements_Array is array (Array_Index range <>) of Element_Type;
253   function "=" (L, R : Elements_Array) return Boolean is abstract;
254
255   type Elements_Array_Ptr is access all Elements_Array;
256
257   type Vector (Capacity : Capacity_Range) is limited record
258      --  In the bounded case, the elements are stored in Elements. In the
259      --  unbounded case, the elements are initially stored in Elements, until
260      --  we run out of room, then we switch to Elements_Ptr.
261      Last         : Extended_Index := No_Index;
262      Elements_Ptr : Elements_Array_Ptr := null;
263      Elements     : aliased Elements_Array (1 .. Capacity);
264   end record;
265
266   --  The primary reason Vector is limited is that in the unbounded case, once
267   --  Elements_Ptr is in use, assignment statements won't work. "X := Y;" will
268   --  cause X and Y to share state; that is, X.Elements_Ptr = Y.Elements_Ptr,
269   --  so for example "Append (X, ...);" will modify BOTH X and Y. That would
270   --  allow SPARK to "prove" things that are false. We could fix that by
271   --  making Vector a controlled type, and override Adjust to make a deep
272   --  copy, but finalization is not allowed in SPARK.
273   --
274   --  Note that (unfortunately) this means that 'Old and 'Loop_Entry are not
275   --  allowed on Vectors.
276
277   function Empty_Vector return Vector is
278     ((Capacity => 0, others => <>));
279
280end Ada.Containers.Formal_Vectors;
281