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------------------------------------------------------------------------------
-- --
-- GNAT LIBRARY COMPONENTS --
-- --
-- ADA.CONTAINERS.HASH_TABLES.GENERIC_OPERATIONS --
-- --
-- S p e c --
-- --
-- Copyright (C) 2004-2022, 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. --
------------------------------------------------------------------------------
-- Hash_Table_Type is used to implement hashed containers. This package
-- declares hash-table operations that do not depend on keys.
with Ada.Streams;
generic
with package HT_Types is
new Generic_Hash_Table_Types (<>);
use HT_Types, HT_Types.Implementation;
with function Hash_Node (Node : Node_Access) return Hash_Type;
with function Next (Node : Node_Access) return Node_Access;
with procedure Set_Next
(Node : Node_Access;
Next : Node_Access);
with function Copy_Node (Source : Node_Access) return Node_Access;
with procedure Free (X : in out Node_Access);
package Ada.Containers.Hash_Tables.Generic_Operations is
pragma Preelaborate;
procedure Free_Hash_Table (Buckets : in out Buckets_Access);
-- First frees the nodes in all non-null buckets of Buckets, and then frees
-- the Buckets array itself.
function Index
(Buckets : Buckets_Type;
Node : Node_Access) return Hash_Type;
pragma Inline (Index);
-- Uses the hash value of Node to compute its Buckets array index
function Index
(Hash_Table : Hash_Table_Type;
Node : Node_Access) return Hash_Type;
pragma Inline (Index);
-- Uses the hash value of Node to compute its Hash_Table buckets array
-- index.
function Checked_Index
(Hash_Table : aliased in out Hash_Table_Type;
Buckets : Buckets_Type;
Node : Node_Access) return Hash_Type;
-- Calls Index, but also locks and unlocks the container, per AI05-0022, in
-- order to detect element tampering by the generic actual Hash function.
function Checked_Index
(Hash_Table : aliased in out Hash_Table_Type;
Node : Node_Access) return Hash_Type;
-- Calls Checked_Index using Hash_Table's buckets array.
procedure Adjust (HT : in out Hash_Table_Type);
-- Used to implement controlled Adjust. It is assumed that HT has the value
-- of the bit-wise copy that immediately follows controlled Finalize.
-- Adjust first allocates a new buckets array for HT (having the same
-- length as the source), and then allocates a copy of each node of source.
procedure Finalize (HT : in out Hash_Table_Type);
-- Used to implement controlled Finalize. It first calls Clear to
-- deallocate any remaining nodes, and then deallocates the buckets array.
generic
with function Find
(HT : Hash_Table_Type;
Key : Node_Access) return Boolean;
function Generic_Equal
(L, R : Hash_Table_Type) return Boolean;
-- Used to implement hashed container equality. For each node in hash table
-- L, it calls Find to search for an equivalent item in hash table R. If
-- Find returns False for any node then Generic_Equal terminates
-- immediately and returns False. Otherwise if Find returns True for every
-- node then Generic_Equal returns True.
procedure Clear (HT : in out Hash_Table_Type);
-- Deallocates each node in hash table HT. (Note that it only deallocates
-- the nodes, not the buckets array. Also note that for bounded containers,
-- the buckets array is not dynamically allocated). Program_Error is raised
-- if the hash table is busy.
procedure Move (Target, Source : in out Hash_Table_Type);
-- Moves (not copies) the buckets array and nodes from Source to
-- Target. Program_Error is raised if Source is busy. The Target is first
-- cleared to deallocate its nodes (implying that Program_Error is also
-- raised if Target is busy). Source is empty following the move.
function Capacity (HT : Hash_Table_Type) return Count_Type;
-- Returns the length of the buckets array
procedure Reserve_Capacity
(HT : in out Hash_Table_Type;
N : Count_Type);
-- If N is greater than the current capacity, then it expands the buckets
-- array to at least the value N. If N is less than the current capacity,
-- then it contracts the buckets array. In either case existing nodes are
-- rehashed onto the new buckets array, and the old buckets array is
-- deallocated. Program_Error is raised if the hash table is busy.
procedure Delete_Node_At_Index
(HT : in out Hash_Table_Type;
Indx : Hash_Type;
X : in out Node_Access);
-- Delete a node whose bucket position is known. Used to remove a node
-- whose element has been modified through a key_preserving reference.
-- We cannot use the value of the element precisely because the current
-- value does not correspond to the hash code that determines the bucket.
procedure Delete_Node_Sans_Free
(HT : in out Hash_Table_Type;
X : Node_Access);
-- Removes node X from the hash table without deallocating the node
function First
(HT : Hash_Table_Type) return Node_Access;
function First
(HT : Hash_Table_Type;
Position : out Hash_Type) return Node_Access;
-- Returns the head of the list in the first (lowest-index) non-empty
-- bucket. Position will be the index of the bucket of the first node.
-- It is provided so that clients can implement efficient iterators.
function Next
(HT : aliased in out Hash_Table_Type;
Node : Node_Access) return Node_Access;
function Next
(HT : aliased in out Hash_Table_Type;
Node : Node_Access;
Position : in out Hash_Type) return Node_Access;
-- Returns the node that immediately follows Node. This corresponds to
-- either the next node in the same bucket, or (if Node is the last node in
-- its bucket) the head of the list in the first non-empty bucket that
-- follows.
--
-- If Node_Position is supplied, then it will be used as a starting point
-- for iteration (Node_Position must be the index of Node's buckets). If it
-- is not supplied, it will be recomputed. It is provided so that clients
-- can implement efficient iterators.
generic
with procedure Process (Node : Node_Access; Position : Hash_Type);
procedure Generic_Iteration_With_Position (HT : Hash_Table_Type);
-- Calls Process for each node in hash table HT
generic
with procedure Process (Node : Node_Access);
procedure Generic_Iteration (HT : Hash_Table_Type);
-- Calls Process for each node in hash table HT
generic
use Ada.Streams;
with procedure Write
(Stream : not null access Root_Stream_Type'Class;
Node : Node_Access);
procedure Generic_Write
(Stream : not null access Root_Stream_Type'Class;
HT : Hash_Table_Type);
-- Used to implement the streaming attribute for hashed containers. It
-- calls Write for each node to write its value into Stream.
generic
use Ada.Streams;
with function New_Node
(Stream : not null access Root_Stream_Type'Class)
return Node_Access;
procedure Generic_Read
(Stream : not null access Root_Stream_Type'Class;
HT : out Hash_Table_Type);
-- Used to implement the streaming attribute for hashed containers. It
-- first clears hash table HT, then populates the hash table by calling
-- New_Node for each item in Stream.
function New_Buckets (Length : Hash_Type) return Buckets_Access;
pragma Inline (New_Buckets);
-- Allocate a new Buckets_Type array with bounds 0 .. Length - 1
procedure Free_Buckets (Buckets : in out Buckets_Access);
pragma Inline (Free_Buckets);
-- Unchecked_Deallocate Buckets
-- Note: New_Buckets and Free_Buckets are needed because Buckets_Access has
-- an empty pool.
end Ada.Containers.Hash_Tables.Generic_Operations;