/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2011 University of California, Los Angeles
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * 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 program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
 */

#include "ndn-limits-window.hpp"

#include "ns3/log.h"

NS_LOG_COMPONENT_DEFINE("ndn.Limits.Window");

namespace ns3 {
namespace ndn {

NS_OBJECT_ENSURE_REGISTERED(LimitsWindow);

TypeId
LimitsWindow::GetTypeId()
{
  static TypeId tid = TypeId("ns3::ndn::Limits::Window")
                        .SetGroupName("Ndn")
                        .SetParent<Limits>()
                        .AddConstructor<LimitsWindow>()

                        .AddTraceSource("CurMaxLimit", "Current maximum limit",
                                        MakeTraceSourceAccessor(&LimitsWindow::m_curMaxLimit))

                        .AddTraceSource("Outstanding", "Number of outstanding interests",
                                        MakeTraceSourceAccessor(&LimitsWindow::m_outstanding));
  return tid;
}

void
LimitsWindow::UpdateCurrentLimit(double limit)
{
  NS_ASSERT_MSG(limit >= 0.0, "Limit should be greater or equal to zero");

  m_curMaxLimit = std::min(limit, GetMaxRate() * GetMaxDelay());
}

bool
LimitsWindow::IsBelowLimit()
{
  if (!IsEnabled())
    return true;

  return (m_curMaxLimit - m_outstanding >= 1.0);
}

void
LimitsWindow::BorrowLimit()
{
  if (!IsEnabled())
    return;

  NS_ASSERT_MSG(m_curMaxLimit - m_outstanding >= 1.0,
                "Should not be possible, unless we IsBelowLimit was not checked correctly");
  m_outstanding += 1;
}

void
LimitsWindow::ReturnLimit()
{
  if (!IsEnabled())
    return;

  NS_ASSERT_MSG(m_outstanding >= (uint32_t)1,
                "Should not be possible, unless we decreasing this number twice somewhere");
  m_outstanding -= 1;

  FireAvailableSlotCallback();
}

} // namespace ndn
} // namespace ns3