/*
 * averagecounter.{cc,hh} -- element counts packets, measures duration 
 * Benjie Chen
 *
 * Copyright (c) 1999-2000 Massachusetts Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, subject to the conditions
 * listed in the Click LICENSE file. These conditions include: you must
 * preserve this copyright notice, and you cannot mention the copyright
 * holders in advertising related to the Software without their permission.
 * The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
 * notice is a summary of the Click LICENSE file; the license in that file is
 * legally binding.
 */

#include <click/config.h>
#include "averagecounter.hh"
#include <click/confparse.hh>
#include <click/straccum.hh>
#include <click/sync.hh>
#include <click/glue.hh>
#include <click/error.hh>
CLICK_DECLS

AverageCounter::AverageCounter()
{
}

AverageCounter::~AverageCounter()
{
}

void
AverageCounter::reset()
{
  _count = 0;
  _first = 0;
  _last = 0;
}

int
AverageCounter::configure(Vector<String> &conf, ErrorHandler *errh)
{
  _ignore = 0;
  if (cp_va_parse(conf, this, errh,
		  cpOptional,
		  cpUnsigned, "number of seconds to ignore", &_ignore,
		  cpEnd) < 0)
    return -1;
  _ignore *= CLICK_HZ;
  return 0;
}

int
AverageCounter::initialize(ErrorHandler *)
{
  reset();
  return 0;
}

Packet *
AverageCounter::simple_action(Packet *p)
{
  _first.compare_and_swap(0, click_jiffies());
  if (click_jiffies() - _first >= _ignore)
    _count++;
  _last = click_jiffies();
  return p;
}

static String
averagecounter_read_count_handler(Element *e, void *)
{
  AverageCounter *c = (AverageCounter *)e;
  return String(c->count());
}

static String
averagecounter_read_rate_handler(Element *e, void *)
{
  AverageCounter *c = (AverageCounter *)e;
  int d = c->last() - c->first();
  d -= c->ignore();
  if (d < 1) d = 1;
  int rate = c->count() * CLICK_HZ / d;
  return String(rate);
}

static int
averagecounter_reset_write_handler
(const String &, Element *e, void *, ErrorHandler *)
{
  AverageCounter *c = (AverageCounter *)e;
  c->reset();
  return 0;
}

void
AverageCounter::add_handlers()
{
  add_read_handler("count", averagecounter_read_count_handler, 0);
  add_read_handler("rate", averagecounter_read_rate_handler, 0);
  add_write_handler("reset", averagecounter_reset_write_handler, 0);
}

CLICK_ENDDECLS
EXPORT_ELEMENT(AverageCounter)
ELEMENT_MT_SAFE(AverageCounter)