| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT LIBRARY COMPONENTS -- |
| -- -- |
| -- ADA.CONTAINERS.RESTRICTED_DOUBLY_LINKED_LISTS -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 2004-2021, 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 -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- 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); |
| 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; |
