------------------------------------------------------------------------------ -- -- -- GNAT LIBRARY COMPONENTS -- -- -- -- ADA.CONTAINERS.RESTRICTED_DOUBLY_LINKED_LISTS -- -- -- -- S p e c -- -- -- -- Copyright (C) 2004-2018, Free Software Foundation, Inc. -- -- -- -- 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 unit was originally developed by Matthew J Heaney. -- ------------------------------------------------------------------------------ -- The doubly-linked list container provides constant-time insertion and -- deletion at all positions, and allows iteration in both the forward and -- reverse directions. This list form allocates storage for all nodes -- statically (there is no dynamic allocation), and a discriminant is used to -- specify the capacity. This container is also "restricted", meaning that -- even though it does raise exceptions (as described below), it does not use -- internal exception handlers. No state changes are made that would need to -- be reverted (in the event of an exception), and so as a consequence, this -- container cannot detect tampering (of cursors or elements). generic type Element_Type is private; with function "=" (Left, Right : Element_Type) return Boolean is <>; package Ada.Containers.Restricted_Doubly_Linked_Lists is pragma Pure; type List (Capacity : Count_Type) is tagged limited private; pragma Preelaborable_Initialization (List); type Cursor is private; pragma Preelaborable_Initialization (Cursor); Empty_List : constant List; -- The default value for list objects declared without an explicit -- initialization expression. No_Element : constant Cursor; -- The default value for cursor objects declared without an explicit -- initialization expression. function "=" (Left, Right : List) return Boolean; -- If Left denotes the same list object as Right, then equality returns -- True. If the length of Left is different from the length of Right, then -- it returns False. Otherwise, list equality iterates over Left and Right, -- comparing the element of Left to the corresponding element of Right -- using the generic actual equality operator for elements. If the elements -- compare False, then the iteration terminates and list equality returns -- False. Otherwise, if all elements return True, then list equality -- returns True. procedure Assign (Target : in out List; Source : List); -- If Target denotes the same list object as Source, the operation does -- nothing. If Target.Capacity is less than Source.Length, then it raises -- Constraint_Error. Otherwise, it clears Target, and then inserts each -- element of Source into Target. function Length (Container : List) return Count_Type; -- Returns the total number of (active) elements in Container function Is_Empty (Container : List) return Boolean; -- Returns True if Container.Length is 0 procedure Clear (Container : in out List); -- Deletes all elements from Container. Note that this is a bounded -- container and so the element is not "deallocated" in the same sense that -- an unbounded form would deallocate the element. Rather, the node is -- relinked off of the active part of the list and onto the inactive part -- of the list (the storage from which new elements are "allocated"). function Element (Position : Cursor) return Element_Type; -- If Position equals No_Element, then Constraint_Error is raised. -- Otherwise, function Element returns the element designed by Position. procedure Replace_Element (Container : in out List; Position : Cursor; New_Item : Element_Type); -- If Position equals No_Element, then Constraint_Error is raised. If -- Position is associated with a list object different from Container, -- Program_Error is raised. Otherwise, the element designated by Position -- is assigned the value New_Item. procedure Query_Element (Position : Cursor; Process : not null access procedure (Element : Element_Type)); -- If Position equals No_Element, then Constraint_Error is raised. -- Otherwise, it calls Process with (a constant view of) the element -- designated by Position as the parameter. procedure Update_Element (Container : in out List; Position : Cursor; Process : not null access procedure (Element : in out Element_Type)); -- If Position equals No_Element, then Constraint_Error is raised. -- Otherwise, it calls Process with (a variable view of) the element -- designated by Position as the parameter. procedure Insert (Container : in out List; Before : Cursor; New_Item : Element_Type; Count : Count_Type := 1); -- Inserts Count new elements, all with the value New_Item, into Container, -- immediately prior to the position specified by Before. If Before has the -- value No_Element, this is interpreted to mean that the elements are -- appended to the list. If Before is associated with a list object -- different from Container, then Program_Error is raised. If there are -- fewer than Count nodes available, then Constraint_Error is raised. procedure Insert (Container : in out List; Before : Cursor; New_Item : Element_Type; Position : out Cursor; Count : Count_Type := 1); -- Inserts elements into Container as described above, but with the -- difference that cursor Position is returned, which designates the first -- of the new elements inserted. If Count is 0, Position returns the value -- Before. procedure Insert (Container : in out List; Before : Cursor; Position : out Cursor; Count : Count_Type := 1); -- Inserts elements in Container as described above, but with the -- difference that the new elements are initialized to the default value -- for objects of type Element_Type. procedure Prepend (Container : in out List; New_Item : Element_Type; Count : Count_Type := 1); -- Inserts Count elements, all having the value New_Item, prior to the -- first element of Container. procedure Append (Container : in out List; New_Item : Element_Type; Count : Count_Type := 1); -- Inserts Count elements, all having the value New_Item, following the -- last element of Container. procedure Delete (Container : in out List; Position : in out Cursor; Count : Count_Type := 1); -- If Position equals No_Element, Constraint_Error is raised. If Position -- is associated with a list object different from Container, then -- Program_Error is raised. Otherwise, the Count nodes starting from -- Position are removed from Container ("removed" meaning that the nodes -- are unlinked from the active nodes of the list and relinked to inactive -- storage). On return, Position is set to No_Element. procedure Delete_First (Container : in out List; Count : Count_Type := 1); -- Removes the first Count nodes from Container procedure Delete_Last (Container : in out List; Count : Count_Type := 1); -- Removes the last Count nodes from Container procedure Reverse_Elements (Container : in out List); -- Relinks the nodes in reverse order procedure Swap (Container : in out List; I, J : Cursor); -- If I or J equals No_Element, then Constraint_Error is raised. If I or J -- is associated with a list object different from Container, then -- Program_Error is raised. Otherwise, Swap exchanges (copies) the values -- of the elements (on the nodes) designated by I and J. procedure Swap_Links (Container : in out List; I, J : Cursor); -- If I or J equals No_Element, then Constraint_Error is raised. If I or J -- is associated with a list object different from Container, then -- Program_Error is raised. Otherwise, Swap exchanges (relinks) the nodes -- designated by I and J. procedure Splice (Container : in out List; Before : Cursor; Position : in out Cursor); -- If Before is associated with a list object different from Container, -- then Program_Error is raised. If Position equals No_Element, then -- Constraint_Error is raised; if it associated with a list object -- different from Container, then Program_Error is raised. Otherwise, the -- node designated by Position is relinked immediately prior to Before. If -- Before equals No_Element, this is interpreted to mean to move the node -- designed by Position to the last end of the list. function First (Container : List) return Cursor; -- If Container is empty, the function returns No_Element. Otherwise, it -- returns a cursor designating the first element. function First_Element (Container : List) return Element_Type; -- Equivalent to Element (First (Container)) function Last (Container : List) return Cursor; -- If Container is empty, the function returns No_Element. Otherwise, it -- returns a cursor designating the last element. function Last_Element (Container : List) return Element_Type; -- Equivalent to Element (Last (Container)) function Next (Position : Cursor) return Cursor; -- If Position equals No_Element or Last (Container), the function returns -- No_Element. Otherwise, it returns a cursor designating the node that -- immediately follows the node designated by Position. procedure Next (Position : in out Cursor); -- Equivalent to Position := Next (Position) function Previous (Position : Cursor) return Cursor; -- If Position equals No_Element or First (Container), the function returns -- No_Element. Otherwise, it returns a cursor designating the node that -- immediately precedes the node designated by Position. procedure Previous (Position : in out Cursor); -- Equivalent to Position := Previous (Position) function Find (Container : List; Item : Element_Type; Position : Cursor := No_Element) return Cursor; -- Searches for the node whose element is equal to Item, starting from -- Position and continuing to the last end of the list. If Position equals -- No_Element, the search starts from the first node. If Position is -- associated with a list object different from Container, then -- Program_Error is raised. If no node is found having an element equal to -- Item, then Find returns No_Element. function Reverse_Find (Container : List; Item : Element_Type; Position : Cursor := No_Element) return Cursor; -- Searches in reverse for the node whose element is equal to Item, -- starting from Position and continuing to the first end of the list. If -- Position equals No_Element, the search starts from the last node. If -- Position is associated with a list object different from Container, then -- Program_Error is raised. If no node is found having an element equal to -- Item, then Reverse_Find returns No_Element. function Contains (Container : List; Item : Element_Type) return Boolean; -- Equivalent to Container.Find (Item) /= No_Element function Has_Element (Position : Cursor) return Boolean; -- Equivalent to Position /= No_Element procedure Iterate (Container : List; Process : not null access procedure (Position : Cursor)); -- Calls Process with a cursor designating each element of Container, in -- order from Container.First to Container.Last. procedure Reverse_Iterate (Container : List; Process : not null access procedure (Position : Cursor)); -- Calls Process with a cursor designating each element of Container, in -- order from Container.Last to Container.First. generic with function "<" (Left, Right : Element_Type) return Boolean is <>; package Generic_Sorting is function Is_Sorted (Container : List) return Boolean; -- Returns False if there exists an element which is less than its -- predecessor. procedure Sort (Container : in out List); -- Sorts the elements of Container (by relinking nodes), according to -- the order specified by the generic formal less-than operator, such -- that smaller elements are first in the list. The sort is stable, -- meaning that the relative order of elements is preserved. end Generic_Sorting; private type Node_Type is limited record Prev : Count_Type'Base; Next : Count_Type; Element : Element_Type; end record; type Node_Array is array (Count_Type range <>) of Node_Type; type List (Capacity : Count_Type) is tagged limited record Nodes : Node_Array (1 .. Capacity) := (others => <>); Free : Count_Type'Base := -1; First : Count_Type := 0; Last : Count_Type := 0; Length : Count_Type := 0; end record; type List_Access is access all List; for List_Access'Storage_Size use 0; type Cursor is record Container : List_Access; Node : Count_Type := 0; end record; Empty_List : constant List := (0, others => <>); No_Element : constant Cursor := (null, 0); end Ada.Containers.Restricted_Doubly_Linked_Lists;