373 lines
13 KiB
Ada
373 lines
13 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT LIBRARY COMPONENTS --
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-- --
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-- ADA.CONTAINERS.FORMAL_DOUBLY_LINKED_LISTS --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 2004-2015, Free Software Foundation, Inc. --
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-- --
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-- This specification is derived from the Ada Reference Manual for use with --
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-- GNAT. The copyright notice above, and the license provisions that follow --
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-- apply solely to the contents of the part following the private keyword. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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------------------------------------------------------------------------------
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-- This spec is derived from Ada.Containers.Bounded_Doubly_Linked_Lists in the
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-- Ada 2012 RM. The modifications are meant to facilitate formal proofs by
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-- making it easier to express properties, and by making the specification of
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-- this unit compatible with SPARK 2014. Note that the API of this unit may be
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-- subject to incompatible changes as SPARK 2014 evolves.
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-- The modifications are:
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-- A parameter for the container is added to every function reading the
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-- contents of a container: Next, Previous, Query_Element, Has_Element,
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-- Iterate, Reverse_Iterate, Element. This change is motivated by the need
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-- to have cursors which are valid on different containers (typically a
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-- container C and its previous version C'Old) for expressing properties,
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-- which is not possible if cursors encapsulate an access to the underlying
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-- container.
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-- There are three new functions:
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-- function Strict_Equal (Left, Right : List) return Boolean;
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-- function First_To_Previous (Container : List; Current : Cursor)
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-- return List;
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-- function Current_To_Last (Container : List; Current : Cursor)
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-- return List;
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-- See subprogram specifications that follow for details
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generic
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type Element_Type is private;
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with function "=" (Left, Right : Element_Type)
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return Boolean is <>;
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package Ada.Containers.Formal_Doubly_Linked_Lists with
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Pure,
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SPARK_Mode
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is
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pragma Annotate (GNATprove, External_Axiomatization);
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pragma Annotate (CodePeer, Skip_Analysis);
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type List (Capacity : Count_Type) is private with
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Iterable => (First => First,
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Next => Next,
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Has_Element => Has_Element,
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Element => Element),
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Default_Initial_Condition => Is_Empty (List);
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pragma Preelaborable_Initialization (List);
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type Cursor is private;
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pragma Preelaborable_Initialization (Cursor);
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Empty_List : constant List;
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No_Element : constant Cursor;
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function "=" (Left, Right : List) return Boolean with
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Global => null;
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function Length (Container : List) return Count_Type with
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Global => null;
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function Is_Empty (Container : List) return Boolean with
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Global => null;
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procedure Clear (Container : in out List) with
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Global => null;
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procedure Assign (Target : in out List; Source : List) with
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Global => null,
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Pre => Target.Capacity >= Length (Source);
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function Copy (Source : List; Capacity : Count_Type := 0) return List with
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Global => null,
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Pre => Capacity = 0 or else Capacity >= Source.Capacity;
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function Element
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(Container : List;
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Position : Cursor) return Element_Type
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with
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Global => null,
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Pre => Has_Element (Container, Position);
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procedure Replace_Element
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(Container : in out List;
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Position : Cursor;
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New_Item : Element_Type)
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with
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Global => null,
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Pre => Has_Element (Container, Position);
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procedure Move (Target : in out List; Source : in out List) with
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Global => null,
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Pre => Target.Capacity >= Length (Source);
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procedure Insert
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(Container : in out List;
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Before : Cursor;
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New_Item : Element_Type;
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Count : Count_Type := 1)
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with
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Global => null,
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Pre => Length (Container) + Count <= Container.Capacity
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and then (Has_Element (Container, Before)
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or else Before = No_Element);
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procedure Insert
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(Container : in out List;
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Before : Cursor;
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New_Item : Element_Type;
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Position : out Cursor;
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Count : Count_Type := 1)
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with
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Global => null,
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Pre => Length (Container) + Count <= Container.Capacity
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and then (Has_Element (Container, Before)
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or else Before = No_Element);
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procedure Insert
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(Container : in out List;
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Before : Cursor;
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Position : out Cursor;
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Count : Count_Type := 1)
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with
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Global => null,
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Pre => Length (Container) + Count <= Container.Capacity
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and then (Has_Element (Container, Before)
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or else Before = No_Element);
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procedure Prepend
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(Container : in out List;
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New_Item : Element_Type;
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Count : Count_Type := 1)
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with
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Global => null,
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Pre => Length (Container) + Count <= Container.Capacity;
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procedure Append
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(Container : in out List;
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New_Item : Element_Type;
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Count : Count_Type := 1)
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with
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Global => null,
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Pre => Length (Container) + Count <= Container.Capacity;
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procedure Delete
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(Container : in out List;
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Position : in out Cursor;
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Count : Count_Type := 1)
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with
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Global => null,
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Pre => Has_Element (Container, Position);
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procedure Delete_First
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(Container : in out List;
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Count : Count_Type := 1)
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with
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Global => null;
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procedure Delete_Last
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(Container : in out List;
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Count : Count_Type := 1)
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with
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Global => null;
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procedure Reverse_Elements (Container : in out List) with
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Global => null;
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procedure Swap
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(Container : in out List;
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I, J : Cursor)
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with
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Global => null,
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Pre => Has_Element (Container, I) and then Has_Element (Container, J);
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procedure Swap_Links
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(Container : in out List;
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I, J : Cursor)
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with
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Global => null,
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Pre => Has_Element (Container, I) and then Has_Element (Container, J);
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procedure Splice
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(Target : in out List;
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Before : Cursor;
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Source : in out List)
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with
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Global => null,
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Pre => Length (Source) + Length (Target) <= Target.Capacity
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and then (Has_Element (Target, Before)
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or else Before = No_Element);
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procedure Splice
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(Target : in out List;
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Before : Cursor;
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Source : in out List;
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Position : in out Cursor)
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with
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Global => null,
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Pre => Length (Source) + Length (Target) <= Target.Capacity
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and then (Has_Element (Target, Before)
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or else Before = No_Element)
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and then Has_Element (Source, Position);
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procedure Splice
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(Container : in out List;
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Before : Cursor;
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Position : Cursor)
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with
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Global => null,
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Pre => 2 * Length (Container) <= Container.Capacity
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and then (Has_Element (Container, Before)
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or else Before = No_Element)
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and then Has_Element (Container, Position);
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function First (Container : List) return Cursor with
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Global => null;
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function First_Element (Container : List) return Element_Type with
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Global => null,
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Pre => not Is_Empty (Container);
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function Last (Container : List) return Cursor with
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Global => null;
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function Last_Element (Container : List) return Element_Type with
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Global => null,
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Pre => not Is_Empty (Container);
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function Next (Container : List; Position : Cursor) return Cursor with
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Global => null,
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Pre => Has_Element (Container, Position) or else Position = No_Element;
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procedure Next (Container : List; Position : in out Cursor) with
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Global => null,
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Pre => Has_Element (Container, Position) or else Position = No_Element;
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function Previous (Container : List; Position : Cursor) return Cursor with
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Global => null,
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Pre => Has_Element (Container, Position) or else Position = No_Element;
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procedure Previous (Container : List; Position : in out Cursor) with
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Global => null,
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Pre => Has_Element (Container, Position) or else Position = No_Element;
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function Find
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(Container : List;
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Item : Element_Type;
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Position : Cursor := No_Element) return Cursor
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with
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Global => null,
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Pre => Has_Element (Container, Position) or else Position = No_Element;
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function Reverse_Find
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(Container : List;
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Item : Element_Type;
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Position : Cursor := No_Element) return Cursor
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with
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Global => null,
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Pre => Has_Element (Container, Position) or else Position = No_Element;
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function Contains
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(Container : List;
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Item : Element_Type) return Boolean
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with
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Global => null;
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function Has_Element (Container : List; Position : Cursor) return Boolean
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with
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Global => null;
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generic
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with function "<" (Left, Right : Element_Type) return Boolean is <>;
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package Generic_Sorting with SPARK_Mode is
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function Is_Sorted (Container : List) return Boolean with
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Global => null;
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procedure Sort (Container : in out List) with
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Global => null;
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procedure Merge (Target, Source : in out List) with
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Global => null;
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end Generic_Sorting;
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function Strict_Equal (Left, Right : List) return Boolean with
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Ghost,
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Global => null;
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-- Strict_Equal returns True if the containers are physically equal, i.e.
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-- they are structurally equal (function "=" returns True) and that they
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-- have the same set of cursors.
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function First_To_Previous (Container : List; Current : Cursor) return List
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with
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Ghost,
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Global => null,
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Pre => Has_Element (Container, Current) or else Current = No_Element;
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function Current_To_Last (Container : List; Current : Cursor) return List
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with
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Ghost,
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Global => null,
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Pre => Has_Element (Container, Current) or else Current = No_Element;
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-- First_To_Previous returns a container containing all elements preceding
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-- Current (excluded) in Container. Current_To_Last returns a container
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-- containing all elements following Current (included) in Container.
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-- These two new functions can be used to express invariant properties in
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-- loops which iterate over containers. First_To_Previous returns the part
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-- of the container already scanned and Current_To_Last the part not
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-- scanned yet.
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private
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pragma SPARK_Mode (Off);
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type Node_Type is record
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Prev : Count_Type'Base := -1;
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Next : Count_Type;
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Element : Element_Type;
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end record;
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function "=" (L, R : Node_Type) return Boolean is abstract;
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type Node_Array is array (Count_Type range <>) of Node_Type;
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function "=" (L, R : Node_Array) return Boolean is abstract;
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type List (Capacity : Count_Type) is tagged record
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Nodes : Node_Array (1 .. Capacity) := (others => <>);
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Free : Count_Type'Base := -1;
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Length : Count_Type := 0;
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First : Count_Type := 0;
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Last : Count_Type := 0;
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end record;
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type Cursor is record
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Node : Count_Type := 0;
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end record;
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Empty_List : constant List := (0, others => <>);
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No_Element : constant Cursor := (Node => 0);
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end Ada.Containers.Formal_Doubly_Linked_Lists;
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