------------------------------------------------------------------------------
-- Copyright (c) 2015, Natacha Porté --
-- --
-- Permission to use, copy, modify, and distribute this software for any --
-- purpose with or without fee is hereby granted, provided that the above --
-- copyright notice and this permission notice appear in all copies. --
-- --
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES --
-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF --
-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR --
-- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES --
-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN --
-- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF --
-- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. --
------------------------------------------------------------------------------
------------------------------------------------------------------------------
-- Natools.S_Expressions.Special_Descriptors provides descriptors blocked --
-- in End_Of_Input or Error states. --
-- The global variables should be task-safe, since there is no actual --
-- change in any of the primitives. --
------------------------------------------------------------------------------
with Natools.S_Expressions.Lockable;
package Natools.S_Expressions.Special_Descriptors is
pragma Preelaborate;
subtype Control_Event is Events.Event with Static_Predicate
=> Control_Event in Events.Error | Events.End_Of_Input;
type Constant_Descriptor (Event : Control_Event) is new Lockable.Descriptor
with null record;
overriding function Current_Event (Object : in Constant_Descriptor)
return Events.Event;
overriding function Current_Atom (Object : in Constant_Descriptor)
return Atom;
overriding function Current_Level (Object : in Constant_Descriptor)
return Natural;
overriding procedure Query_Atom
(Object : in Constant_Descriptor;
Process : not null access procedure (Data : in Atom));
overriding procedure Read_Atom
(Object : in Constant_Descriptor;
Data : out Atom;
Length : out Count);
overriding procedure Next
(Object : in out Constant_Descriptor;
Event : out Events.Event);
overriding procedure Lock
(Object : in out Constant_Descriptor;
State : out Lockable.Lock_State);
overriding procedure Unlock
(Object : in out Constant_Descriptor;
State : in out Lockable.Lock_State;
Finish : in Boolean := True);
Empty_Descriptor : Constant_Descriptor (Events.End_Of_Input);
Error_Descriptor : Constant_Descriptor (Events.Error);
end Natools.S_Expressions.Special_Descriptors;