338 lines
15 KiB
Ada
338 lines
15 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT LIBRARY COMPONENTS --
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-- --
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-- ADA.CONTAINERS.RESTRICTED_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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-- 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 unit was originally developed by Matthew J Heaney. --
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------------------------------------------------------------------------------
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-- The doubly-linked list container provides constant-time insertion and
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-- deletion at all positions, and allows iteration in both the forward and
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-- reverse directions. This list form allocates storage for all nodes
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-- statically (there is no dynamic allocation), and a discriminant is used to
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-- specify the capacity. This container is also "restricted", meaning that
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-- even though it does raise exceptions (as described below), it does not use
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-- internal exception handlers. No state changes are made that would need to
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-- be reverted (in the event of an exception), and so as a consequence, this
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-- container cannot detect tampering (of cursors or elements).
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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.Restricted_Doubly_Linked_Lists is
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pragma Pure;
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type List (Capacity : Count_Type) is tagged limited private;
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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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-- The default value for list objects declared without an explicit
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-- initialization expression.
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No_Element : constant Cursor;
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-- The default value for cursor objects declared without an explicit
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-- initialization expression.
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function "=" (Left, Right : List) return Boolean;
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-- If Left denotes the same list object as Right, then equality returns
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-- True. If the length of Left is different from the length of Right, then
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-- it returns False. Otherwise, list equality iterates over Left and Right,
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-- comparing the element of Left to the corresponding element of Right
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-- using the generic actual equality operator for elements. If the elements
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-- compare False, then the iteration terminates and list equality returns
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-- False. Otherwise, if all elements return True, then list equality
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-- returns True.
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procedure Assign (Target : in out List; Source : List);
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-- If Target denotes the same list object as Source, the operation does
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-- nothing. If Target.Capacity is less than Source.Length, then it raises
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-- Constraint_Error. Otherwise, it clears Target, and then inserts each
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-- element of Source into Target.
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function Length (Container : List) return Count_Type;
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-- Returns the total number of (active) elements in Container
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function Is_Empty (Container : List) return Boolean;
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-- Returns True if Container.Length is 0
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procedure Clear (Container : in out List);
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-- Deletes all elements from Container. Note that this is a bounded
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-- container and so the element is not "deallocated" in the same sense that
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-- an unbounded form would deallocate the element. Rather, the node is
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-- relinked off of the active part of the list and onto the inactive part
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-- of the list (the storage from which new elements are "allocated").
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function Element (Position : Cursor) return Element_Type;
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-- If Position equals No_Element, then Constraint_Error is raised.
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-- Otherwise, function Element returns the element designed by 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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-- If Position equals No_Element, then Constraint_Error is raised. If
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-- Position is associated with a list object different from Container,
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-- Program_Error is raised. Otherwise, the element designated by Position
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-- is assigned the value New_Item.
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procedure Query_Element
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(Position : Cursor;
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Process : not null access procedure (Element : Element_Type));
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-- If Position equals No_Element, then Constraint_Error is raised.
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-- Otherwise, it calls Process with (a constant view of) the element
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-- designated by Position as the parameter.
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procedure Update_Element
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(Container : in out List;
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Position : Cursor;
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Process : not null access procedure (Element : in out Element_Type));
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-- If Position equals No_Element, then Constraint_Error is raised.
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-- Otherwise, it calls Process with (a variable view of) the element
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-- designated by Position as the parameter.
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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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-- Inserts Count new elements, all with the value New_Item, into Container,
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-- immediately prior to the position specified by Before. If Before has the
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-- value No_Element, this is interpreted to mean that the elements are
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-- appended to the list. If Before is associated with a list object
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-- different from Container, then Program_Error is raised. If there are
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-- fewer than Count nodes available, then Constraint_Error is raised.
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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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-- Inserts elements into Container as described above, but with the
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-- difference that cursor Position is returned, which designates the first
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-- of the new elements inserted. If Count is 0, Position returns the value
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-- Before.
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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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-- Inserts elements in Container as described above, but with the
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-- difference that the new elements are initialized to the default value
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-- for objects of type Element_Type.
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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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-- Inserts Count elements, all having the value New_Item, prior to the
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-- first element of Container.
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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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-- Inserts Count elements, all having the value New_Item, following the
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-- last element of Container.
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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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-- If Position equals No_Element, Constraint_Error is raised. If Position
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-- is associated with a list object different from Container, then
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-- Program_Error is raised. Otherwise, the Count nodes starting from
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-- Position are removed from Container ("removed" meaning that the nodes
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-- are unlinked from the active nodes of the list and relinked to inactive
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-- storage). On return, Position is set to No_Element.
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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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-- Removes the first Count nodes from Container
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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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-- Removes the last Count nodes from Container
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procedure Reverse_Elements (Container : in out List);
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-- Relinks the nodes in reverse order
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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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-- If I or J equals No_Element, then Constraint_Error is raised. If I or J
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-- is associated with a list object different from Container, then
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-- Program_Error is raised. Otherwise, Swap exchanges (copies) the values
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-- of the elements (on the nodes) designated by I and 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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-- If I or J equals No_Element, then Constraint_Error is raised. If I or J
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-- is associated with a list object different from Container, then
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-- Program_Error is raised. Otherwise, Swap exchanges (relinks) the nodes
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-- designated by I and J.
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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 : in out Cursor);
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-- If Before is associated with a list object different from Container,
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-- then Program_Error is raised. If Position equals No_Element, then
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-- Constraint_Error is raised; if it associated with a list object
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-- different from Container, then Program_Error is raised. Otherwise, the
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-- node designated by Position is relinked immediately prior to Before. If
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-- Before equals No_Element, this is interpreted to mean to move the node
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-- designed by Position to the last end of the list.
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function First (Container : List) return Cursor;
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-- If Container is empty, the function returns No_Element. Otherwise, it
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-- returns a cursor designating the first element.
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function First_Element (Container : List) return Element_Type;
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-- Equivalent to Element (First (Container))
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function Last (Container : List) return Cursor;
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-- If Container is empty, the function returns No_Element. Otherwise, it
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-- returns a cursor designating the last element.
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function Last_Element (Container : List) return Element_Type;
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-- Equivalent to Element (Last (Container))
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function Next (Position : Cursor) return Cursor;
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-- If Position equals No_Element or Last (Container), the function returns
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-- No_Element. Otherwise, it returns a cursor designating the node that
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-- immediately follows the node designated by Position.
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procedure Next (Position : in out Cursor);
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-- Equivalent to Position := Next (Position)
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function Previous (Position : Cursor) return Cursor;
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-- If Position equals No_Element or First (Container), the function returns
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-- No_Element. Otherwise, it returns a cursor designating the node that
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-- immediately precedes the node designated by Position.
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procedure Previous (Position : in out Cursor);
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-- Equivalent to Position := Previous (Position)
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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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-- Searches for the node whose element is equal to Item, starting from
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-- Position and continuing to the last end of the list. If Position equals
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-- No_Element, the search starts from the first node. If Position is
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-- associated with a list object different from Container, then
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-- Program_Error is raised. If no node is found having an element equal to
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-- Item, then Find returns 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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-- Searches in reverse for the node whose element is equal to Item,
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-- starting from Position and continuing to the first end of the list. If
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-- Position equals No_Element, the search starts from the last node. If
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-- Position is associated with a list object different from Container, then
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-- Program_Error is raised. If no node is found having an element equal to
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-- Item, then Reverse_Find returns 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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-- Equivalent to Container.Find (Item) /= No_Element
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function Has_Element (Position : Cursor) return Boolean;
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-- Equivalent to Position /= No_Element
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procedure Iterate
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(Container : List;
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Process : not null access procedure (Position : Cursor));
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-- Calls Process with a cursor designating each element of Container, in
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-- order from Container.First to Container.Last.
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procedure Reverse_Iterate
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(Container : List;
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Process : not null access procedure (Position : Cursor));
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-- Calls Process with a cursor designating each element of Container, in
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-- order from Container.Last to Container.First.
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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 is
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function Is_Sorted (Container : List) return Boolean;
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-- Returns False if there exists an element which is less than its
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-- predecessor.
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procedure Sort (Container : in out List);
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-- Sorts the elements of Container (by relinking nodes), according to
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-- the order specified by the generic formal less-than operator, such
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-- that smaller elements are first in the list. The sort is stable,
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-- meaning that the relative order of elements is preserved.
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end Generic_Sorting;
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private
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type Node_Type is limited record
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Prev : Count_Type'Base;
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Next : Count_Type;
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Element : Element_Type;
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end record;
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type Node_Array is array (Count_Type range <>) of Node_Type;
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type List (Capacity : Count_Type) is tagged limited record
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Nodes : Node_Array (1 .. Capacity) := (others => <>);
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Free : Count_Type'Base := -1;
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First : Count_Type := 0;
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Last : Count_Type := 0;
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Length : Count_Type := 0;
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end record;
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type List_Access is access all List;
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for List_Access'Storage_Size use 0;
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type Cursor is
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record
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Container : List_Access;
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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 := (null, 0);
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end Ada.Containers.Restricted_Doubly_Linked_Lists;
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