File : adagio-bandwidth_manager.adb
------------------------------------------------------------------------------
-- ADAGIO - ADALID - AENEA. --
-- --
-- Copyright (C) 2003 --
-- A. Mosteo. --
-- --
-- Authors: A. Mosteo. (adagio@mosteo.com) --
-- --
-- If you have any questions in regard to this software, please address --
-- them to the above email. --
-- --
-- This program is free software; you can redistribute it and/or modify --
-- it under the terms of the GNU General Public License as published by --
-- the Free Software Foundation; either version 2 of the License, or (at --
-- your option) any later version. --
-- --
-- This program is distributed in the hope that it will be useful, but --
-- WITHOUT ANY WARRANTY; without even the implied warranty of --
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU --
-- General Public License for more details. --
-- --
-- You should have received a copy of the GNU General Public License --
-- along with this library; if not, write to the Free Software Foundation, --
-- Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. --
-- --
-- You are not allowed to use any part of this code to develop a program --
-- whose output would be used to harass or prosecute other users of the --
-- networks Adagio connects with. All data collected with Adagio or a tool --
-- containing Adagio code about other network users must remain --
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-- harass or legally prosecute these users. --
------------------------------------------------------------------------------
-- $Id: adagio-bandwidth_manager.adb,v 1.8 2004/01/21 21:05:48 Jano Exp $
-- Task for bandwidth management
with Adagio.Trace;
package body Adagio.Bandwidth_manager is
-- Bandwidth is the bytes/second to manage
-- Period is the period for feedback. Longer ones allow the use
-- of unused bandwidth for more time.
protected body Object is
procedure Refresh;
pragma Inline (Refresh);
procedure Report;
pragma Inline (Report);
---------------
-- Available --
---------------
-- Gives the available bandwidth at this moment (real + extra):
procedure Available (Bandwidth : out Natural) is
begin
Refresh;
begin
Bandwidth := Remanent + Unused;
exception
when Constraint_error =>
Bandwidth := Natural'Last;
end;
end Available;
------------
-- Commit --
------------
-- Issue a bandwidth petition. Awarded can be less that solicited.
-- Extra flag requests bandwidth from unused past cycles.
procedure Commit (
Desired : in Natural;
Awarded : out Natural;
Extra : in Boolean := false) is
begin
Refresh;
if Extra then
Awarded := Natural'Min (Desired, Unused);
Unused := Unused - Awarded;
else
Awarded := Natural'Min (Desired, Remanent);
Remanent := Remanent - Awarded;
end if;
end Commit;
-------------
-- Refresh --
-------------
-- Recomputes if necessary the BW available
procedure Refresh is
use Ada.Calendar;
Elapsed : Duration := Clock - Last_req;
begin
-- Check for too many time elapsed:
if Elapsed >= Gap then
-- Keep unused from past cycles:
Unused := Remanent;
-- Update remanent:
begin
Remanent := Natural (Float (Bandwidth) * Float (Gap));
exception
when Constraint_error =>
Remanent := Natural'Last;
end;
-- Update clock:
declare
Gaps : Natural :=
Natural (Float'Floor (Float (Elapsed) / Float (Gap)));
begin
Last_req := Last_req + Gap * Duration (Gaps);
end;
end if;
end Refresh;
------------
-- Report --
------------
-- Debug reports
procedure Report is
begin
Trace.Log ("Rem:" & Remanent'Img & "; Unu:" & Unused'Img,
Trace.Always);
end Report;
end Object;
end Adagio.Bandwidth_manager;