------------------------------------------------------------------------------ -- -- -- GNAT LIBRARY COMPONENTS -- -- -- -- ADA.CONTAINERS.FORMAL_DOUBLY_LINKED_LISTS -- -- -- -- S p e c -- -- -- -- Copyright (C) 2004-2013, Free Software Foundation, Inc. -- -- -- -- This specification is derived from the Ada Reference Manual for use with -- -- GNAT. The copyright notice above, and the license provisions that follow -- -- apply solely to the contents of the part following the private keyword. -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 3, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- As a special exception under Section 7 of GPL version 3, you are granted -- -- additional permissions described in the GCC Runtime Library Exception, -- -- version 3.1, as published by the Free Software Foundation. -- -- -- -- You should have received a copy of the GNU General Public License and -- -- a copy of the GCC Runtime Library Exception along with this program; -- -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- -- . -- ------------------------------------------------------------------------------ -- This spec is derived from Ada.Containers.Bounded_Doubly_Linked_Lists in the -- Ada 2012 RM. The modifications are meant to facilitate formal proofs by -- making it easier to express properties, and by making the specification of -- this unit compatible with SPARK 2014. Note that the API of this unit may be -- subject to incompatible changes as SPARK 2014 evolves. -- The modifications are: -- A parameter for the container is added to every function reading the -- contents of a container: Next, Previous, Query_Element, Has_Element, -- Iterate, Reverse_Iterate, Element. This change is motivated by the need -- to have cursors which are valid on different containers (typically a -- container C and its previous version C'Old) for expressing properties, -- which is not possible if cursors encapsulate an access to the underlying -- container. -- There are three new functions: -- function Strict_Equal (Left, Right : List) return Boolean; -- function Left (Container : List; Position : Cursor) return List; -- function Right (Container : List; Position : Cursor) return List; -- See subprogram specifications that follow for details generic type Element_Type is private; with function "=" (Left, Right : Element_Type) return Boolean is <>; package Ada.Containers.Formal_Doubly_Linked_Lists is pragma Pure; type List (Capacity : Count_Type) is private; pragma Preelaborable_Initialization (List); type Cursor is private; pragma Preelaborable_Initialization (Cursor); Empty_List : constant List; No_Element : constant Cursor; function "=" (Left, Right : List) return Boolean; function Length (Container : List) return Count_Type; function Is_Empty (Container : List) return Boolean; procedure Clear (Container : in out List); procedure Assign (Target : in out List; Source : List) with Pre => Target.Capacity >= Length (Source); function Copy (Source : List; Capacity : Count_Type := 0) return List; function Element (Container : List; Position : Cursor) return Element_Type with Pre => Has_Element (Container, Position); procedure Replace_Element (Container : in out List; Position : Cursor; New_Item : Element_Type) with Pre => Has_Element (Container, Position); procedure Move (Target : in out List; Source : in out List) with Pre => Target.Capacity >= Length (Source); procedure Insert (Container : in out List; Before : Cursor; New_Item : Element_Type; Count : Count_Type := 1) with Pre => Length (Container) + Count <= Container.Capacity and then (Has_Element (Container, Before) or else Before = No_Element); procedure Insert (Container : in out List; Before : Cursor; New_Item : Element_Type; Position : out Cursor; Count : Count_Type := 1) with Pre => Length (Container) + Count <= Container.Capacity and then (Has_Element (Container, Before) or else Before = No_Element); procedure Insert (Container : in out List; Before : Cursor; Position : out Cursor; Count : Count_Type := 1) with Pre => Length (Container) + Count <= Container.Capacity and then (Has_Element (Container, Before) or else Before = No_Element); procedure Prepend (Container : in out List; New_Item : Element_Type; Count : Count_Type := 1) with Pre => Length (Container) + Count <= Container.Capacity; procedure Append (Container : in out List; New_Item : Element_Type; Count : Count_Type := 1) with Pre => Length (Container) + Count <= Container.Capacity; procedure Delete (Container : in out List; Position : in out Cursor; Count : Count_Type := 1) with Pre => Has_Element (Container, Position); procedure Delete_First (Container : in out List; Count : Count_Type := 1); procedure Delete_Last (Container : in out List; Count : Count_Type := 1); procedure Reverse_Elements (Container : in out List); procedure Swap (Container : in out List; I, J : Cursor) with Pre => Has_Element (Container, I) and then Has_Element (Container, J); procedure Swap_Links (Container : in out List; I, J : Cursor) with Pre => Has_Element (Container, I) and then Has_Element (Container, J); procedure Splice (Target : in out List; Before : Cursor; Source : in out List) with Pre => Length (Source) + Length (Target) <= Target.Capacity and then (Has_Element (Target, Before) or else Before = No_Element); procedure Splice (Target : in out List; Before : Cursor; Source : in out List; Position : in out Cursor) with Pre => Length (Source) + Length (Target) <= Target.Capacity and then (Has_Element (Target, Before) or else Before = No_Element) and then Has_Element (Source, Position); procedure Splice (Container : in out List; Before : Cursor; Position : Cursor) with Pre => 2 * Length (Container) <= Container.Capacity and then (Has_Element (Container, Before) or else Before = No_Element) and then Has_Element (Container, Position); function First (Container : List) return Cursor; function First_Element (Container : List) return Element_Type with Pre => not Is_Empty (Container); function Last (Container : List) return Cursor; function Last_Element (Container : List) return Element_Type with Pre => not Is_Empty (Container); function Next (Container : List; Position : Cursor) return Cursor with Pre => Has_Element (Container, Position) or else Position = No_Element; procedure Next (Container : List; Position : in out Cursor) with Pre => Has_Element (Container, Position) or else Position = No_Element; function Previous (Container : List; Position : Cursor) return Cursor with Pre => Has_Element (Container, Position) or else Position = No_Element; procedure Previous (Container : List; Position : in out Cursor) with Pre => Has_Element (Container, Position) or else Position = No_Element; function Find (Container : List; Item : Element_Type; Position : Cursor := No_Element) return Cursor with Pre => Has_Element (Container, Position) or else Position = No_Element; function Reverse_Find (Container : List; Item : Element_Type; Position : Cursor := No_Element) return Cursor with Pre => Has_Element (Container, Position) or else Position = No_Element; function Contains (Container : List; Item : Element_Type) return Boolean; function Has_Element (Container : List; Position : Cursor) return Boolean; generic with function "<" (Left, Right : Element_Type) return Boolean is <>; package Generic_Sorting is function Is_Sorted (Container : List) return Boolean; procedure Sort (Container : in out List); procedure Merge (Target, Source : in out List); end Generic_Sorting; function Strict_Equal (Left, Right : List) return Boolean; -- Strict_Equal returns True if the containers are physically equal, i.e. -- they are structurally equal (function "=" returns True) and that they -- have the same set of cursors. function Left (Container : List; Position : Cursor) return List with Pre => Has_Element (Container, Position) or else Position = No_Element; function Right (Container : List; Position : Cursor) return List with Pre => Has_Element (Container, Position) or else Position = No_Element; -- Left returns a container containing all elements preceding Position -- (excluded) in Container. Right returns a container containing all -- elements following Position (included) in Container. These two new -- functions can be used to express invariant properties in loops which -- iterate over containers. Left returns the part of the container already -- scanned and Right the part not scanned yet. private type Node_Type is record Prev : Count_Type'Base := -1; Next : Count_Type; Element : Element_Type; end record; function "=" (L, R : Node_Type) return Boolean is abstract; type Node_Array is array (Count_Type range <>) of Node_Type; function "=" (L, R : Node_Array) return Boolean is abstract; type List (Capacity : Count_Type) is tagged record Nodes : Node_Array (1 .. Capacity) := (others => <>); Free : Count_Type'Base := -1; Length : Count_Type := 0; First : Count_Type := 0; Last : Count_Type := 0; end record; type Cursor is record Node : Count_Type := 0; end record; Empty_List : constant List := (0, others => <>); No_Element : constant Cursor := (Node => 0); end Ada.Containers.Formal_Doubly_Linked_Lists;