| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT LIBRARY COMPONENTS -- |
| -- -- |
| -- A D A . C O N T A I N E R S . M U L T I W A Y _ T R E E S -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 2004-2022, 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 -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- This unit was originally developed by Matthew J Heaney. -- |
| ------------------------------------------------------------------------------ |
| |
| with Ada.Iterator_Interfaces; |
| |
| with Ada.Containers.Helpers; |
| private with Ada.Finalization; |
| private with Ada.Streams; |
| private with Ada.Strings.Text_Buffers; |
| |
| generic |
| type Element_Type is private; |
| |
| with function "=" (Left, Right : Element_Type) return Boolean is <>; |
| |
| package Ada.Containers.Multiway_Trees with |
| SPARK_Mode => Off |
| is |
| pragma Annotate (CodePeer, Skip_Analysis); |
| pragma Preelaborate; |
| pragma Remote_Types; |
| |
| type Tree is tagged private |
| with Constant_Indexing => Constant_Reference, |
| Variable_Indexing => Reference, |
| Default_Iterator => Iterate, |
| Iterator_Element => Element_Type; |
| pragma Preelaborable_Initialization (Tree); |
| |
| type Cursor is private; |
| pragma Preelaborable_Initialization (Cursor); |
| |
| Empty_Tree : constant Tree; |
| |
| No_Element : constant Cursor; |
| function Has_Element (Position : Cursor) return Boolean; |
| |
| package Tree_Iterator_Interfaces is new |
| Ada.Iterator_Interfaces (Cursor, Has_Element); |
| |
| function Equal_Subtree |
| (Left_Position : Cursor; |
| Right_Position : Cursor) return Boolean; |
| |
| function "=" (Left, Right : Tree) return Boolean; |
| |
| function Is_Empty (Container : Tree) return Boolean; |
| |
| function Node_Count (Container : Tree) return Count_Type; |
| |
| function Subtree_Node_Count (Position : Cursor) return Count_Type; |
| |
| function Depth (Position : Cursor) return Count_Type; |
| |
| function Is_Root (Position : Cursor) return Boolean; |
| |
| function Is_Leaf (Position : Cursor) return Boolean; |
| |
| function Root (Container : Tree) return Cursor; |
| |
| procedure Clear (Container : in out Tree); |
| |
| function Element (Position : Cursor) return Element_Type; |
| |
| procedure Replace_Element |
| (Container : in out Tree; |
| Position : Cursor; |
| New_Item : Element_Type); |
| |
| procedure Query_Element |
| (Position : Cursor; |
| Process : not null access procedure (Element : Element_Type)); |
| |
| procedure Update_Element |
| (Container : in out Tree; |
| Position : Cursor; |
| Process : not null access procedure (Element : in out Element_Type)); |
| |
| type Constant_Reference_Type |
| (Element : not null access constant Element_Type) is private |
| with Implicit_Dereference => Element; |
| |
| type Reference_Type |
| (Element : not null access Element_Type) is private |
| with Implicit_Dereference => Element; |
| |
| function Constant_Reference |
| (Container : aliased Tree; |
| Position : Cursor) return Constant_Reference_Type; |
| pragma Inline (Constant_Reference); |
| |
| function Reference |
| (Container : aliased in out Tree; |
| Position : Cursor) return Reference_Type; |
| pragma Inline (Reference); |
| |
| procedure Assign (Target : in out Tree; Source : Tree); |
| |
| function Copy (Source : Tree) return Tree; |
| |
| procedure Move (Target : in out Tree; Source : in out Tree); |
| |
| procedure Delete_Leaf |
| (Container : in out Tree; |
| Position : in out Cursor); |
| |
| procedure Delete_Subtree |
| (Container : in out Tree; |
| Position : in out Cursor); |
| |
| procedure Swap |
| (Container : in out Tree; |
| I, J : Cursor); |
| |
| function Find |
| (Container : Tree; |
| Item : Element_Type) return Cursor; |
| |
| -- This version of the AI: |
| -- 10-06-02 AI05-0136-1/07 |
| -- declares Find_In_Subtree this way: |
| -- |
| -- function Find_In_Subtree |
| -- (Container : Tree; |
| -- Item : Element_Type; |
| -- Position : Cursor) return Cursor; |
| -- |
| -- It seems that the Container parameter is there by mistake, but we need |
| -- an official ruling from the ARG. ??? |
| |
| function Find_In_Subtree |
| (Position : Cursor; |
| Item : Element_Type) return Cursor; |
| |
| -- This version of the AI: |
| -- 10-06-02 AI05-0136-1/07 |
| -- declares Ancestor_Find this way: |
| -- |
| -- function Ancestor_Find |
| -- (Container : Tree; |
| -- Item : Element_Type; |
| -- Position : Cursor) return Cursor; |
| -- |
| -- It seems that the Container parameter is there by mistake, but we need |
| -- an official ruling from the ARG. ??? |
| |
| function Ancestor_Find |
| (Position : Cursor; |
| Item : Element_Type) return Cursor; |
| |
| function Contains |
| (Container : Tree; |
| Item : Element_Type) return Boolean; |
| |
| procedure Iterate |
| (Container : Tree; |
| Process : not null access procedure (Position : Cursor)); |
| |
| procedure Iterate_Subtree |
| (Position : Cursor; |
| Process : not null access procedure (Position : Cursor)); |
| |
| function Iterate (Container : Tree) |
| return Tree_Iterator_Interfaces.Forward_Iterator'Class; |
| |
| function Iterate_Subtree (Position : Cursor) |
| return Tree_Iterator_Interfaces.Forward_Iterator'Class; |
| |
| function Iterate_Children |
| (Container : Tree; |
| Parent : Cursor) |
| return Tree_Iterator_Interfaces.Reversible_Iterator'Class; |
| |
| function Child_Count (Parent : Cursor) return Count_Type; |
| |
| function Child_Depth (Parent, Child : Cursor) return Count_Type; |
| |
| procedure Insert_Child |
| (Container : in out Tree; |
| Parent : Cursor; |
| Before : Cursor; |
| New_Item : Element_Type; |
| Count : Count_Type := 1); |
| |
| procedure Insert_Child |
| (Container : in out Tree; |
| Parent : Cursor; |
| Before : Cursor; |
| New_Item : Element_Type; |
| Position : out Cursor; |
| Count : Count_Type := 1); |
| |
| procedure Insert_Child |
| (Container : in out Tree; |
| Parent : Cursor; |
| Before : Cursor; |
| Position : out Cursor; |
| Count : Count_Type := 1); |
| |
| procedure Prepend_Child |
| (Container : in out Tree; |
| Parent : Cursor; |
| New_Item : Element_Type; |
| Count : Count_Type := 1); |
| |
| procedure Append_Child |
| (Container : in out Tree; |
| Parent : Cursor; |
| New_Item : Element_Type; |
| Count : Count_Type := 1); |
| |
| procedure Delete_Children |
| (Container : in out Tree; |
| Parent : Cursor); |
| |
| procedure Copy_Subtree |
| (Target : in out Tree; |
| Parent : Cursor; |
| Before : Cursor; |
| Source : Cursor); |
| |
| procedure Splice_Subtree |
| (Target : in out Tree; |
| Parent : Cursor; |
| Before : Cursor; |
| Source : in out Tree; |
| Position : in out Cursor); |
| |
| procedure Splice_Subtree |
| (Container : in out Tree; |
| Parent : Cursor; |
| Before : Cursor; |
| Position : Cursor); |
| |
| procedure Splice_Children |
| (Target : in out Tree; |
| Target_Parent : Cursor; |
| Before : Cursor; |
| Source : in out Tree; |
| Source_Parent : Cursor); |
| |
| procedure Splice_Children |
| (Container : in out Tree; |
| Target_Parent : Cursor; |
| Before : Cursor; |
| Source_Parent : Cursor); |
| |
| function Parent (Position : Cursor) return Cursor; |
| |
| function First_Child (Parent : Cursor) return Cursor; |
| |
| function First_Child_Element (Parent : Cursor) return Element_Type; |
| |
| function Last_Child (Parent : Cursor) return Cursor; |
| |
| function Last_Child_Element (Parent : Cursor) return Element_Type; |
| |
| function Next_Sibling (Position : Cursor) return Cursor; |
| |
| function Previous_Sibling (Position : Cursor) return Cursor; |
| |
| procedure Next_Sibling (Position : in out Cursor); |
| |
| procedure Previous_Sibling (Position : in out Cursor); |
| |
| -- This version of the AI: |
| -- 10-06-02 AI05-0136-1/07 |
| -- declares Iterate_Children this way: |
| -- |
| -- procedure Iterate_Children |
| -- (Container : Tree; |
| -- Parent : Cursor; |
| -- Process : not null access procedure (Position : Cursor)); |
| -- |
| -- It seems that the Container parameter is there by mistake, but we need |
| -- an official ruling from the ARG. ??? |
| |
| procedure Iterate_Children |
| (Parent : Cursor; |
| Process : not null access procedure (Position : Cursor)); |
| |
| procedure Reverse_Iterate_Children |
| (Parent : Cursor; |
| Process : not null access procedure (Position : Cursor)); |
| |
| private |
| -- A node of this multiway tree comprises an element and a list of children |
| -- (that are themselves trees). The root node is distinguished because it |
| -- contains only children: it does not have an element itself. |
| |
| -- This design feature puts two design goals in tension with one another: |
| -- (1) treat the root node the same as any other node |
| -- (2) not declare any objects of type Element_Type unnecessarily |
| |
| -- To satisfy (1), we could simply declare the Root node of the tree |
| -- using the normal Tree_Node_Type, but that would mean that (2) is not |
| -- satisfied. To resolve the tension (in favor of (2)), we declare the |
| -- component Root as having a different node type, without an Element |
| -- component (thus satisfying goal (2)) but otherwise identical to a normal |
| -- node, and then use Unchecked_Conversion to convert an access object |
| -- designating the Root node component to the access type designating a |
| -- normal, non-root node (thus satisfying goal (1)). We make an explicit |
| -- check for Root when there is any attempt to manipulate the Element |
| -- component of the node (a check required by the RM anyway). |
| |
| -- In order to be explicit about node (and pointer) representation, we |
| -- specify that the respective node types have convention C, to ensure |
| -- that the layout of the components of the node records is the same, |
| -- thus guaranteeing that (unchecked) conversions between access types |
| -- designating each kind of node type is a meaningful conversion. |
| |
| use Ada.Containers.Helpers; |
| package Implementation is new Generic_Implementation; |
| use Implementation; |
| |
| type Tree_Node_Type; |
| type Tree_Node_Access is access all Tree_Node_Type; |
| pragma Convention (C, Tree_Node_Access); |
| pragma No_Strict_Aliasing (Tree_Node_Access); |
| -- The above-mentioned Unchecked_Conversion is a violation of the normal |
| -- aliasing rules. |
| |
| type Children_Type is record |
| First : Tree_Node_Access; |
| Last : Tree_Node_Access; |
| end record; |
| |
| -- See the comment above. This declaration must exactly match the |
| -- declaration of Root_Node_Type (except for the Element component). |
| |
| type Tree_Node_Type is record |
| Parent : Tree_Node_Access; |
| Prev : Tree_Node_Access; |
| Next : Tree_Node_Access; |
| Children : Children_Type; |
| Element : aliased Element_Type; |
| end record; |
| pragma Convention (C, Tree_Node_Type); |
| |
| -- See the comment above. This declaration must match the declaration of |
| -- Tree_Node_Type (except for the Element component). |
| |
| type Root_Node_Type is record |
| Parent : Tree_Node_Access; |
| Prev : Tree_Node_Access; |
| Next : Tree_Node_Access; |
| Children : Children_Type; |
| end record; |
| pragma Convention (C, Root_Node_Type); |
| |
| for Root_Node_Type'Alignment use Standard'Maximum_Alignment; |
| -- The alignment has to be large enough to allow Root_Node to Tree_Node |
| -- access value conversions, and Tree_Node_Type's alignment may be bumped |
| -- up by the Element component. |
| |
| use Ada.Finalization; |
| |
| -- The Count component of type Tree represents the number of nodes that |
| -- have been (dynamically) allocated. It does not include the root node |
| -- itself. As implementors, we decide to cache this value, so that the |
| -- selector function Node_Count can execute in O(1) time, in order to be |
| -- consistent with the behavior of the Length selector function for other |
| -- standard container library units. This does mean, however, that the |
| -- two-container forms for Splice_XXX (that move subtrees across tree |
| -- containers) will execute in O(n) time, because we must count the number |
| -- of nodes in the subtree(s) that get moved. (We resolve the tension |
| -- between Node_Count and Splice_XXX in favor of Node_Count, under the |
| -- assumption that Node_Count is the more common operation). |
| |
| type Tree is new Controlled with record |
| Root : aliased Root_Node_Type; |
| TC : aliased Tamper_Counts; |
| Count : Count_Type := 0; |
| end record with Put_Image => Put_Image; |
| |
| procedure Put_Image |
| (S : in out Ada.Strings.Text_Buffers.Root_Buffer_Type'Class; V : Tree); |
| |
| overriding procedure Adjust (Container : in out Tree); |
| |
| overriding procedure Finalize (Container : in out Tree) renames Clear; |
| |
| use Ada.Streams; |
| |
| procedure Write |
| (Stream : not null access Root_Stream_Type'Class; |
| Container : Tree); |
| |
| for Tree'Write use Write; |
| |
| procedure Read |
| (Stream : not null access Root_Stream_Type'Class; |
| Container : out Tree); |
| |
| for Tree'Read use Read; |
| |
| type Tree_Access is access all Tree; |
| for Tree_Access'Storage_Size use 0; |
| |
| type Cursor is record |
| Container : Tree_Access; |
| Node : Tree_Node_Access; |
| end record; |
| |
| procedure Write |
| (Stream : not null access Root_Stream_Type'Class; |
| Position : Cursor); |
| |
| for Cursor'Write use Write; |
| |
| procedure Read |
| (Stream : not null access Root_Stream_Type'Class; |
| Position : out Cursor); |
| |
| for Cursor'Read use Read; |
| |
| subtype Reference_Control_Type is Implementation.Reference_Control_Type; |
| -- It is necessary to rename this here, so that the compiler can find it |
| |
| type Constant_Reference_Type |
| (Element : not null access constant Element_Type) is |
| record |
| Control : Reference_Control_Type := |
| raise Program_Error with "uninitialized reference"; |
| -- The RM says, "The default initialization of an object of |
| -- type Constant_Reference_Type or Reference_Type propagates |
| -- Program_Error." |
| end record; |
| |
| procedure Read |
| (Stream : not null access Root_Stream_Type'Class; |
| Item : out Constant_Reference_Type); |
| |
| for Constant_Reference_Type'Read use Read; |
| |
| procedure Write |
| (Stream : not null access Root_Stream_Type'Class; |
| Item : Constant_Reference_Type); |
| |
| for Constant_Reference_Type'Write use Write; |
| |
| type Reference_Type |
| (Element : not null access Element_Type) is |
| record |
| Control : Reference_Control_Type := |
| raise Program_Error with "uninitialized reference"; |
| -- The RM says, "The default initialization of an object of |
| -- type Constant_Reference_Type or Reference_Type propagates |
| -- Program_Error." |
| end record; |
| |
| procedure Read |
| (Stream : not null access Root_Stream_Type'Class; |
| Item : out Reference_Type); |
| |
| for Reference_Type'Read use Read; |
| |
| procedure Write |
| (Stream : not null access Root_Stream_Type'Class; |
| Item : Reference_Type); |
| |
| for Reference_Type'Write use Write; |
| |
| -- Three operations are used to optimize in the expansion of "for ... of" |
| -- loops: the Next(Cursor) procedure in the visible part, and the following |
| -- Pseudo_Reference and Get_Element_Access functions. See Exp_Ch5 for |
| -- details. |
| |
| function Pseudo_Reference |
| (Container : aliased Tree'Class) return Reference_Control_Type; |
| pragma Inline (Pseudo_Reference); |
| -- Creates an object of type Reference_Control_Type pointing to the |
| -- container, and increments the Lock. Finalization of this object will |
| -- decrement the Lock. |
| |
| type Element_Access is access all Element_Type with |
| Storage_Size => 0; |
| |
| function Get_Element_Access |
| (Position : Cursor) return not null Element_Access; |
| -- Returns a pointer to the element designated by Position. |
| |
| Empty_Tree : constant Tree := (Controlled with others => <>); |
| |
| No_Element : constant Cursor := (others => <>); |
| |
| end Ada.Containers.Multiway_Trees; |