File : adagio-throttle_stream.ads
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-- ADAGIO - ADALID - AENEA. --
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-- $Id: adagio-throttle_stream.ads,v 1.3 2004/01/21 21:05:42 Jano Exp $
-- Throttle stream
with Ada.Streams; use Ada.Streams;
use Ada;
with Adagio.Throttler;
package Adagio.Throttle_stream is
-- New stream type:
type Throttle_stream (Throttle: access Throttler.Object) is new
Ada.Streams.Root_Stream_Type with private;
type Stream_access is access all Throttle_stream;
-- Overriden primitives:
-- At each read, a Throttle.Cycle_work is performed.
-- Thus, a Start_work should be ensured right before use.
-- Lacking that, a HUGE delay could be triggered.
-- Note that the creator will do that.
procedure Read(
Stream : in out Throttle_stream;
Item : out Stream_Element_Array;
Last : out Stream_Element_Offset);
-- Only reading is implemented.
-- Thus, any call to this raises Unimplemented_error.
procedure Write(
Stream : in out Throttle_stream;
Item : in Stream_Element_Array);
-- Creation. It links a new buffered stream with any other stream:
-- Will perform a Throttle.Start_work;
procedure Get_throttle_stream
(TStream: in out Throttle_stream;
Stream : access Streams.Root_stream_type'Class);
private
type Counter_type is mod 2 ** 14;
type Root_stream_access is access all Streams.Root_stream_type'Class;
type Throttle_stream(Throttle: access Throttler.Object) is new
Ada.Streams.Root_Stream_Type with
record
Source: Root_stream_access; -- or any descendent.
Counter: Counter_type:= 0;
end record;
end Adagio.Throttle_stream;