adolfo_filter.h

这是一个著名的应用层组播中间件的源码

//Copyright (c) 2004, Charles Killian, Adolfo Rodriguez, Dejan Kostic, Sooraj Bhat, and Amin Vahdat
//All rights reserved.
//
//Redistribution and use in source and binary forms, with or without
//modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in
//     the documentation and/or other materials provided with the
//     distribution.
//   * Neither the names of Duke University nor The University of
//     California, San Diego, nor the names of its contributors
//     may be used to endorse or promote products derived from
//     this software without specific prior written permission.
//
//THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
//AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
//IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
//DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
//FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
//DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
//SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
//CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
//OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
//USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef __adolfo_filter
#define __adolfo_filter
#include "generic_filter.h"
#include "scheduler.h"
#include <list>
using namespace std;

class adolfo_filter:public generic_filter 
{
 
 public:

  static const int HISTORY_VALUE=4000;
  static const double BANDWIDTH_WINDOW=5.0; // how long to keep average in seconds

  adolfo_filter	();
  ~adolfo_filter	( );
  void inline update () { 
    double now =  Scheduler::instance().clock();
    history.push_back (now);
    //  history_count++;
    check();
  }
  void remove_entry(int);
  void  clear ();
  double get_value();
  void initialize(); // REB: replaces constructor initialization
 public:
 protected:
  int  lock ();
  void  unlock ();
  void inline check () {
    double elapsed_time;
    double now = Scheduler::instance().clock();

    while (history.size() > 0 && (now - history.front())> BANDWIDTH_WINDOW) {
      history.pop_front();
    }      

    if (history.size() == 0 ) {
      value = 0.0;
    }
    else {
      if (now-time_initial < BANDWIDTH_WINDOW)
        elapsed_time = now-time_initial;
      else
        elapsed_time = BANDWIDTH_WINDOW;    
      value = data_packet_size*8*history.size()/elapsed_time;
    }

  }
  list < double > history; 
  int data_packet_size;
 private:
  double time_initial;
};
#endif //__adolfo_filter