| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT LIBRARY COMPONENTS -- |
| -- -- |
| -- A D A . C O N T A I N E R S . H A S H E D _ S E T 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; |
| |
| private with Ada.Containers.Hash_Tables; |
| 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 Hash (Element : Element_Type) return Hash_Type; |
| |
| with function Equivalent_Elements |
| (Left, Right : Element_Type) return Boolean; |
| |
| with function "=" (Left, Right : Element_Type) return Boolean is <>; |
| |
| package Ada.Containers.Hashed_Sets with |
| SPARK_Mode => Off |
| is |
| pragma Annotate (CodePeer, Skip_Analysis); |
| pragma Preelaborate; |
| pragma Remote_Types; |
| |
| type Set is tagged private |
| with |
| Constant_Indexing => Constant_Reference, |
| Default_Iterator => Iterate, |
| Iterator_Element => Element_Type, |
| Aggregate => (Empty => Empty, |
| Add_Unnamed => Include); |
| |
| pragma Preelaborable_Initialization (Set); |
| |
| type Cursor is private; |
| pragma Preelaborable_Initialization (Cursor); |
| |
| function "=" (Left, Right : Cursor) return Boolean; |
| -- The representation of cursors includes a component used to optimize |
| -- iteration over sets. This component may become unreliable after |
| -- multiple set insertions, and must be excluded from cursor equality, |
| -- so we need to provide an explicit definition for it, instead of |
| -- using predefined equality (as implied by a questionable comment |
| -- in the RM). This is also the case for hashed maps, and affects the |
| -- use of Insert primitives in hashed structures. |
| |
| Empty_Set : constant Set; |
| -- Set objects declared without an initialization expression are |
| -- initialized to the value Empty_Set. |
| |
| No_Element : constant Cursor; |
| -- Cursor objects declared without an initialization expression are |
| -- initialized to the value No_Element. |
| |
| function Has_Element (Position : Cursor) return Boolean; |
| -- Equivalent to Position /= No_Element |
| |
| package Set_Iterator_Interfaces is new |
| Ada.Iterator_Interfaces (Cursor, Has_Element); |
| |
| function Empty (Capacity : Count_Type := 1000) return Set; |
| |
| function "=" (Left, Right : Set) return Boolean; |
| -- For each element in Left, set equality attempts to find the equal |
| -- element in Right; if a search fails, then set equality immediately |
| -- returns False. The search works by calling Hash to find the bucket in |
| -- the Right set that corresponds to the Left element. If the bucket is |
| -- non-empty, the search calls the generic formal element equality operator |
| -- to compare the element (in Left) to the element of each node in the |
| -- bucket (in Right); the search terminates when a matching node in the |
| -- bucket is found, or the nodes in the bucket are exhausted. (Note that |
| -- element equality is called here, not Equivalent_Elements. Set equality |
| -- is the only operation in which element equality is used. Compare set |
| -- equality to Equivalent_Sets, which does call Equivalent_Elements.) |
| |
| function Equivalent_Sets (Left, Right : Set) return Boolean; |
| -- Similar to set equality, with the difference that the element in Left is |
| -- compared to the elements in Right using the generic formal |
| -- Equivalent_Elements operation instead of element equality. |
| |
| function To_Set (New_Item : Element_Type) return Set; |
| -- Constructs a singleton set comprising New_Element. To_Set calls Hash to |
| -- determine the bucket for New_Item. |
| |
| function Capacity (Container : Set) return Count_Type; |
| -- Returns the current capacity of the set. Capacity is the maximum length |
| -- before which rehashing in guaranteed not to occur. |
| |
| procedure Reserve_Capacity (Container : in out Set; Capacity : Count_Type); |
| -- Adjusts the current capacity, by allocating a new buckets array. If the |
| -- requested capacity is less than the current capacity, then the capacity |
| -- is contracted (to a value not less than the current length). If the |
| -- requested capacity is greater than the current capacity, then the |
| -- capacity is expanded (to a value not less than what is requested). In |
| -- either case, the nodes are rehashed from the old buckets array onto the |
| -- new buckets array (Hash is called once for each existing element in |
| -- order to compute the new index), and then the old buckets array is |
| -- deallocated. |
| |
| function Length (Container : Set) return Count_Type; |
| -- Returns the number of items in the set |
| |
| function Is_Empty (Container : Set) return Boolean; |
| -- Equivalent to Length (Container) = 0 |
| |
| procedure Clear (Container : in out Set); |
| -- Removes all of the items from the set |
| |
| function Element (Position : Cursor) return Element_Type; |
| -- Returns the element of the node designated by the cursor |
| |
| procedure Replace_Element |
| (Container : in out Set; |
| Position : Cursor; |
| New_Item : Element_Type); |
| -- If New_Item is equivalent (as determined by calling Equivalent_Elements) |
| -- to the element of the node designated by Position, then New_Element is |
| -- assigned to that element. Otherwise, it calls Hash to determine the |
| -- bucket for New_Item. If the bucket is not empty, then it calls |
| -- Equivalent_Elements for each node in that bucket to determine whether |
| -- New_Item is equivalent to an element in that bucket. If |
| -- Equivalent_Elements returns True then Program_Error is raised (because |
| -- an element may appear only once in the set); otherwise, New_Item is |
| -- assigned to the node designated by Position, and the node is moved to |
| -- its new bucket. |
| |
| procedure Query_Element |
| (Position : Cursor; |
| Process : not null access procedure (Element : Element_Type)); |
| -- Calls Process with the element (having only a constant view) of the node |
| -- designed by the cursor. |
| |
| type Constant_Reference_Type |
| (Element : not null access constant Element_Type) is private |
| with Implicit_Dereference => Element; |
| |
| function Constant_Reference |
| (Container : aliased Set; |
| Position : Cursor) return Constant_Reference_Type; |
| pragma Inline (Constant_Reference); |
| |
| procedure Assign (Target : in out Set; Source : Set); |
| |
| function Copy (Source : Set; Capacity : Count_Type := 0) return Set; |
| |
| procedure Move (Target : in out Set; Source : in out Set); |
| -- Clears Target (if it's not empty), and then moves (not copies) the |
| -- buckets array and nodes from Source to Target. |
| |
| procedure Insert |
| (Container : in out Set; |
| New_Item : Element_Type; |
| Position : out Cursor; |
| Inserted : out Boolean); |
| -- Conditionally inserts New_Item into the set. If New_Item is already in |
| -- the set, then Inserted returns False and Position designates the node |
| -- containing the existing element (which is not modified). If New_Item is |
| -- not already in the set, then Inserted returns True and Position |
| -- designates the newly-inserted node containing New_Item. The search for |
| -- an existing element works as follows. Hash is called to determine |
| -- New_Item's bucket; if the bucket is non-empty, then Equivalent_Elements |
| -- is called to compare New_Item to the element of each node in that |
| -- bucket. If the bucket is empty, or there were no equivalent elements in |
| -- the bucket, the search "fails" and the New_Item is inserted in the set |
| -- (and Inserted returns True); otherwise, the search "succeeds" (and |
| -- Inserted returns False). |
| |
| procedure Insert (Container : in out Set; New_Item : Element_Type); |
| -- Attempts to insert New_Item into the set, performing the usual insertion |
| -- search (which involves calling both Hash and Equivalent_Elements); if |
| -- the search succeeds (New_Item is equivalent to an element already in the |
| -- set, and so was not inserted), then this operation raises |
| -- Constraint_Error. (This version of Insert is similar to Replace, but |
| -- having the opposite exception behavior. It is intended for use when you |
| -- want to assert that the item is not already in the set.) |
| |
| procedure Include (Container : in out Set; New_Item : Element_Type); |
| -- Attempts to insert New_Item into the set. If an element equivalent to |
| -- New_Item is already in the set (the insertion search succeeded, and |
| -- hence New_Item was not inserted), then the value of New_Item is assigned |
| -- to the existing element. (This insertion operation only raises an |
| -- exception if cursor tampering occurs. It is intended for use when you |
| -- want to insert the item in the set, and you don't care whether an |
| -- equivalent element is already present.) |
| |
| procedure Replace (Container : in out Set; New_Item : Element_Type); |
| -- Searches for New_Item in the set; if the search fails (because an |
| -- equivalent element was not in the set), then it raises |
| -- Constraint_Error. Otherwise, the existing element is assigned the value |
| -- New_Item. (This is similar to Insert, but with the opposite exception |
| -- behavior. It is intended for use when you want to assert that the item |
| -- is already in the set.) |
| |
| procedure Exclude (Container : in out Set; Item : Element_Type); |
| -- Searches for Item in the set, and if found, removes its node from the |
| -- set and then deallocates it. The search works as follows. The operation |
| -- calls Hash to determine the item's bucket; if the bucket is not empty, |
| -- it calls Equivalent_Elements to compare Item to the element of each node |
| -- in the bucket. (This is the deletion analog of Include. It is intended |
| -- for use when you want to remove the item from the set, but don't care |
| -- whether the item is already in the set.) |
| |
| procedure Delete (Container : in out Set; Item : Element_Type); |
| -- Searches for Item in the set (which involves calling both Hash and |
| -- Equivalent_Elements). If the search fails, then the operation raises |
| -- Constraint_Error. Otherwise it removes the node from the set and then |
| -- deallocates it. (This is the deletion analog of non-conditional |
| -- Insert. It is intended for use when you want to assert that the item is |
| -- already in the set.) |
| |
| procedure Delete (Container : in out Set; Position : in out Cursor); |
| -- Removes the node designated by Position from the set, and then |
| -- deallocates the node. The operation calls Hash to determine the bucket, |
| -- and then compares Position to each node in the bucket until there's a |
| -- match (it does not call Equivalent_Elements). |
| |
| procedure Union (Target : in out Set; Source : Set); |
| -- The operation first calls Reserve_Capacity if the current capacity is |
| -- less than the sum of the lengths of Source and Target. It then iterates |
| -- over the Source set, and conditionally inserts each element into Target. |
| |
| function Union (Left, Right : Set) return Set; |
| -- The operation first copies the Left set to the result, and then iterates |
| -- over the Right set to conditionally insert each element into the result. |
| |
| function "or" (Left, Right : Set) return Set renames Union; |
| |
| procedure Intersection (Target : in out Set; Source : Set); |
| -- Iterates over the Target set (calling First and Next), calling Find to |
| -- determine whether the element is in Source. If an equivalent element is |
| -- not found in Source, the element is deleted from Target. |
| |
| function Intersection (Left, Right : Set) return Set; |
| -- Iterates over the Left set, calling Find to determine whether the |
| -- element is in Right. If an equivalent element is found, it is inserted |
| -- into the result set. |
| |
| function "and" (Left, Right : Set) return Set renames Intersection; |
| |
| procedure Difference (Target : in out Set; Source : Set); |
| -- Iterates over the Source (calling First and Next), calling Find to |
| -- determine whether the element is in Target. If an equivalent element is |
| -- found, it is deleted from Target. |
| |
| function Difference (Left, Right : Set) return Set; |
| -- Iterates over the Left set, calling Find to determine whether the |
| -- element is in the Right set. If an equivalent element is not found, the |
| -- element is inserted into the result set. |
| |
| function "-" (Left, Right : Set) return Set renames Difference; |
| |
| procedure Symmetric_Difference (Target : in out Set; Source : Set); |
| -- The operation first calls Reserve_Capacity if the current capacity is |
| -- less than the sum of the lengths of Source and Target. It then iterates |
| -- over the Source set, searching for the element in Target (calling Hash |
| -- and Equivalent_Elements). If an equivalent element is found, it is |
| -- removed from Target; otherwise it is inserted into Target. |
| |
| function Symmetric_Difference (Left, Right : Set) return Set; |
| -- The operation first iterates over the Left set. It calls Find to |
| -- determine whether the element is in the Right set. If no equivalent |
| -- element is found, the element from Left is inserted into the result. The |
| -- operation then iterates over the Right set, to determine whether the |
| -- element is in the Left set. If no equivalent element is found, the Right |
| -- element is inserted into the result. |
| |
| function "xor" (Left, Right : Set) return Set |
| renames Symmetric_Difference; |
| |
| function Overlap (Left, Right : Set) return Boolean; |
| -- Iterates over the Left set (calling First and Next), calling Find to |
| -- determine whether the element is in the Right set. If an equivalent |
| -- element is found, the operation immediately returns True. The operation |
| -- returns False if the iteration over Left terminates without finding any |
| -- equivalent element in Right. |
| |
| function Is_Subset (Subset : Set; Of_Set : Set) return Boolean; |
| -- Iterates over Subset (calling First and Next), calling Find to determine |
| -- whether the element is in Of_Set. If no equivalent element is found in |
| -- Of_Set, the operation immediately returns False. The operation returns |
| -- True if the iteration over Subset terminates without finding an element |
| -- not in Of_Set (that is, every element in Subset is equivalent to an |
| -- element in Of_Set). |
| |
| function First (Container : Set) return Cursor; |
| -- Returns a cursor that designates the first non-empty bucket, by |
| -- searching from the beginning of the buckets array. |
| |
| function Next (Position : Cursor) return Cursor; |
| -- Returns a cursor that designates the node that follows the current one |
| -- designated by Position. If Position designates the last node in its |
| -- bucket, the operation calls Hash to compute the index of this bucket, |
| -- and searches the buckets array for the first non-empty bucket, starting |
| -- from that index; otherwise, it simply follows the link to the next node |
| -- in the same bucket. |
| |
| procedure Next (Position : in out Cursor); |
| -- Equivalent to Position := Next (Position) |
| |
| function Find |
| (Container : Set; |
| Item : Element_Type) return Cursor; |
| -- Searches for Item in the set. Find calls Hash to determine the item's |
| -- bucket; if the bucket is not empty, it calls Equivalent_Elements to |
| -- compare Item to each element in the bucket. If the search succeeds, Find |
| -- returns a cursor designating the node containing the equivalent element; |
| -- otherwise, it returns No_Element. |
| |
| function Contains (Container : Set; Item : Element_Type) return Boolean; |
| -- Equivalent to Find (Container, Item) /= No_Element |
| |
| function Equivalent_Elements (Left, Right : Cursor) return Boolean; |
| -- Returns the result of calling Equivalent_Elements with the elements of |
| -- the nodes designated by cursors Left and Right. |
| |
| function Equivalent_Elements |
| (Left : Cursor; |
| Right : Element_Type) return Boolean; |
| -- Returns the result of calling Equivalent_Elements with element of the |
| -- node designated by Left and element Right. |
| |
| function Equivalent_Elements |
| (Left : Element_Type; |
| Right : Cursor) return Boolean; |
| -- Returns the result of calling Equivalent_Elements with element Left and |
| -- the element of the node designated by Right. |
| |
| procedure Iterate |
| (Container : Set; |
| Process : not null access procedure (Position : Cursor)); |
| -- Calls Process for each node in the set |
| |
| function Iterate |
| (Container : Set) return Set_Iterator_Interfaces.Forward_Iterator'Class; |
| |
| generic |
| type Key_Type (<>) is private; |
| |
| with function Key (Element : Element_Type) return Key_Type; |
| |
| with function Hash (Key : Key_Type) return Hash_Type; |
| |
| with function Equivalent_Keys (Left, Right : Key_Type) return Boolean; |
| |
| package Generic_Keys is |
| |
| function Key (Position : Cursor) return Key_Type; |
| -- Applies generic formal operation Key to the element of the node |
| -- designated by Position. |
| |
| function Element (Container : Set; Key : Key_Type) return Element_Type; |
| -- Searches (as per the key-based Find) for the node containing Key, and |
| -- returns the associated element. |
| |
| procedure Replace |
| (Container : in out Set; |
| Key : Key_Type; |
| New_Item : Element_Type); |
| -- Searches (as per the key-based Find) for the node containing Key, and |
| -- then replaces the element of that node (as per the element-based |
| -- Replace_Element). |
| |
| procedure Exclude (Container : in out Set; Key : Key_Type); |
| -- Searches for Key in the set, and if found, removes its node from the |
| -- set and then deallocates it. The search works by first calling Hash |
| -- (on Key) to determine the bucket; if the bucket is not empty, it |
| -- calls Equivalent_Keys to compare parameter Key to the value of |
| -- generic formal operation Key applied to element of each node in the |
| -- bucket. |
| |
| procedure Delete (Container : in out Set; Key : Key_Type); |
| -- Deletes the node containing Key as per Exclude, with the difference |
| -- that Constraint_Error is raised if Key is not found. |
| |
| function Find (Container : Set; Key : Key_Type) return Cursor; |
| -- Searches for the node containing Key, and returns a cursor |
| -- designating the node. The search works by first calling Hash (on Key) |
| -- to determine the bucket. If the bucket is not empty, the search |
| -- compares Key to the element of each node in the bucket, and returns |
| -- the matching node. The comparison itself works by applying the |
| -- generic formal Key operation to the element of the node, and then |
| -- calling generic formal operation Equivalent_Keys. |
| |
| function Contains (Container : Set; Key : Key_Type) return Boolean; |
| -- Equivalent to Find (Container, Key) /= No_Element |
| |
| procedure Update_Element_Preserving_Key |
| (Container : in out Set; |
| Position : Cursor; |
| Process : not null access |
| procedure (Element : in out Element_Type)); |
| -- Calls Process with the element of the node designated by Position, |
| -- but with the restriction that the key-value of the element is not |
| -- modified. The operation first makes a copy of the value returned by |
| -- applying generic formal operation Key on the element of the node, and |
| -- then calls Process with the element. The operation verifies that the |
| -- key-part has not been modified by calling generic formal operation |
| -- Equivalent_Keys to compare the saved key-value to the value returned |
| -- by applying generic formal operation Key to the post-Process value of |
| -- element. If the key values compare equal then the operation |
| -- completes. Otherwise, the node is removed from the set and |
| -- Program_Error is raised. |
| |
| type Reference_Type (Element : not null access Element_Type) is private |
| with Implicit_Dereference => Element; |
| |
| function Reference_Preserving_Key |
| (Container : aliased in out Set; |
| Position : Cursor) return Reference_Type; |
| |
| function Constant_Reference |
| (Container : aliased Set; |
| Key : Key_Type) return Constant_Reference_Type; |
| |
| function Reference_Preserving_Key |
| (Container : aliased in out Set; |
| Key : Key_Type) return Reference_Type; |
| |
| private |
| use Ada.Streams; |
| type Set_Access is access all Set; |
| for Set_Access'Storage_Size use 0; |
| |
| -- Key_Preserving references must carry information to allow removal |
| -- of elements whose value may have been altered improperly, i.e. have |
| -- been given values incompatible with the hash-code of the previous |
| -- value, and are thus in the wrong bucket. (RM 18.7 (96.6/3)) |
| |
| -- We cannot store the key directly because it is an unconstrained type. |
| -- To avoid using additional dynamic allocation we store the old cursor |
| -- which simplifies possible removal. This is not possible for some |
| -- other set types. |
| |
| -- The mechanism is different for Update_Element_Preserving_Key, as |
| -- in that case the check that buckets have not changed is performed |
| -- at the time of the update, not when the reference is finalized. |
| |
| package Impl is new Helpers.Generic_Implementation; |
| |
| type Reference_Control_Type is |
| new Impl.Reference_Control_Type with |
| record |
| Container : Set_Access; |
| Index : Hash_Type; |
| Old_Pos : Cursor; |
| Old_Hash : Hash_Type; |
| end record; |
| |
| overriding procedure Finalize (Control : in out Reference_Control_Type); |
| pragma Inline (Finalize); |
| |
| type Reference_Type (Element : not null access Element_Type) is record |
| Control : Reference_Control_Type; |
| 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; |
| end Generic_Keys; |
| |
| private |
| pragma Inline (Next); |
| |
| type Node_Type; |
| type Node_Access is access Node_Type; |
| |
| type Node_Type is limited record |
| Element : aliased Element_Type; |
| Next : Node_Access; |
| end record; |
| |
| package HT_Types is |
| new Hash_Tables.Generic_Hash_Table_Types (Node_Type, Node_Access); |
| |
| type Set is new Ada.Finalization.Controlled with record |
| HT : HT_Types.Hash_Table_Type; |
| end record with Put_Image => Put_Image; |
| |
| procedure Put_Image |
| (S : in out Ada.Strings.Text_Buffers.Root_Buffer_Type'Class; V : Set); |
| |
| overriding procedure Adjust (Container : in out Set); |
| |
| overriding procedure Finalize (Container : in out Set); |
| |
| use HT_Types, HT_Types.Implementation; |
| use Ada.Finalization; |
| use Ada.Streams; |
| |
| procedure Write |
| (Stream : not null access Root_Stream_Type'Class; |
| Container : Set); |
| |
| for Set'Write use Write; |
| |
| procedure Read |
| (Stream : not null access Root_Stream_Type'Class; |
| Container : out Set); |
| |
| for Set'Read use Read; |
| |
| type Set_Access is access all Set; |
| for Set_Access'Storage_Size use 0; |
| |
| type Cursor is record |
| Container : Set_Access; |
| -- Access to this cursor's container |
| |
| Node : Node_Access; |
| -- Access to the node pointed to by this cursor |
| |
| Position : Hash_Type := Hash_Type'Last; |
| -- Position of the node in the buckets of the container. If this is |
| -- equal to Hash_Type'Last, then it will not be used. Position is |
| -- not requried by the implementation, but improves the efficiency |
| -- of various operations. |
| -- |
| -- However, this value must be maintained so that the predefined |
| -- equality operation acts as required by RM A.18.7-17/2, which |
| -- states: "The predefined "=" operator for type Cursor returns True |
| -- if both cursors are No_Element, or designate the same element |
| -- in the same container." |
| end record; |
| |
| procedure Write |
| (Stream : not null access Root_Stream_Type'Class; |
| Item : Cursor); |
| |
| for Cursor'Write use Write; |
| |
| procedure Read |
| (Stream : not null access Root_Stream_Type'Class; |
| Item : 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; |
| |
| -- 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 Sem_Ch5 for |
| -- details. |
| |
| function Pseudo_Reference |
| (Container : aliased Set'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_Set : constant Set := (Controlled with others => <>); |
| |
| No_Element : constant Cursor := |
| (Container => null, Node => null, Position => Hash_Type'Last); |
| |
| type Iterator is new Limited_Controlled and |
| Set_Iterator_Interfaces.Forward_Iterator with |
| record |
| Container : Set_Access; |
| end record |
| with Disable_Controlled => not T_Check; |
| |
| overriding function First (Object : Iterator) return Cursor; |
| |
| overriding function Next |
| (Object : Iterator; |
| Position : Cursor) return Cursor; |
| overriding procedure Finalize (Object : in out Iterator); |
| |
| end Ada.Containers.Hashed_Sets; |