/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2007 University of Washington
 *
 * 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
 *
 *
 * This file incorporates work covered by the following copyright and  
 * permission notice:  
 *
 * Copyright (c) 1997 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 * Contributed by the Daedalus Research Group, UC Berkeley
 * (http://daedalus.cs.berkeley.edu)
 *
 * This code has been ported from ns-2 (queue/errmodel.{cc,h}
 */

#include <math.h>

#include "error-model.h"

#include "ns3/packet.h"
#include "ns3/assert.h"
#include "ns3/log.h"
#include "ns3/random-variable.h"
#include "ns3/boolean.h"
#include "ns3/enum.h"
#include "ns3/double.h"

NS_LOG_COMPONENT_DEFINE ("ErrorModel");

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (ErrorModel);

TypeId ErrorModel::GetTypeId (void)
{ 
  static TypeId tid = TypeId ("ns3::ErrorModel")
    .SetParent<Object> ()
    .AddAttribute ("IsEnabled", "Whether this ErrorModel is enabled or not.",
                   BooleanValue (true),
                   MakeBooleanAccessor (&ErrorModel::m_enable),
                   MakeBooleanChecker ())
  ;
  return tid;
}

ErrorModel::ErrorModel () :
  m_enable (true) 
{
  NS_LOG_FUNCTION_NOARGS ();
}

ErrorModel::~ErrorModel ()
{
  NS_LOG_FUNCTION_NOARGS ();
}

bool
ErrorModel::IsCorrupt (Ptr<Packet> p)
{
  NS_LOG_FUNCTION_NOARGS ();
  bool result;
  // Insert any pre-conditions here
  result = DoCorrupt (p);
  // Insert any post-conditions here
  return result;
}

void
ErrorModel::Reset (void)
{
  NS_LOG_FUNCTION_NOARGS ();
  DoReset ();
}

void
ErrorModel::Enable (void)
{
  NS_LOG_FUNCTION_NOARGS ();
  m_enable = true;
}

void
ErrorModel::Disable (void)
{
  NS_LOG_FUNCTION_NOARGS ();
  m_enable = false;
}

bool
ErrorModel::IsEnabled (void) const
{
  NS_LOG_FUNCTION_NOARGS ();
  return m_enable;
}

//
// RateErrorModel
//

NS_OBJECT_ENSURE_REGISTERED (RateErrorModel);

TypeId RateErrorModel::GetTypeId (void)
{ 
  static TypeId tid = TypeId ("ns3::RateErrorModel")
    .SetParent<ErrorModel> ()
    .AddConstructor<RateErrorModel> ()
    .AddAttribute ("ErrorUnit", "The error unit",
                   EnumValue (ERROR_UNIT_BYTE),
                   MakeEnumAccessor (&RateErrorModel::m_unit),
                   MakeEnumChecker (ERROR_UNIT_BIT, "ERROR_UNIT_BIT",
                                    ERROR_UNIT_BYTE, "ERROR_UNIT_BYTE",
                                    ERROR_UNIT_PACKET, "ERROR_UNIT_PACKET"))
    .AddAttribute ("ErrorRate", "The error rate.",
                   DoubleValue (0.0),
                   MakeDoubleAccessor (&RateErrorModel::m_rate),
                   MakeDoubleChecker<double> ())
    .AddAttribute ("RanVar", "The decision variable attached to this error model.",
                   RandomVariableValue (UniformVariable (0.0, 1.0)),
                   MakeRandomVariableAccessor (&RateErrorModel::m_ranvar),
                   MakeRandomVariableChecker ())
  ;
  return tid;
}


RateErrorModel::RateErrorModel ()
{
  NS_LOG_FUNCTION_NOARGS ();
}

RateErrorModel::~RateErrorModel () 
{
  NS_LOG_FUNCTION_NOARGS ();
}

RateErrorModel::ErrorUnit
RateErrorModel::GetUnit (void) const 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  return m_unit; 
}

void 
RateErrorModel::SetUnit (enum ErrorUnit error_unit) 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  m_unit = error_unit; 
}

double
RateErrorModel::GetRate (void) const 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  return m_rate; 
}

void 
RateErrorModel::SetRate (double rate)
{ 
  NS_LOG_FUNCTION_NOARGS ();
  m_rate = rate;
}

void 
RateErrorModel::SetRandomVariable (const RandomVariable &ranvar)
{
  NS_LOG_FUNCTION_NOARGS ();
  m_ranvar = ranvar;
}

bool 
RateErrorModel::DoCorrupt (Ptr<Packet> p) 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  if (!IsEnabled ())
    {
      return false;
    }
  switch (m_unit) 
    {
    case ERROR_UNIT_PACKET:
      return DoCorruptPkt (p);
    case ERROR_UNIT_BYTE:
      return DoCorruptByte (p);
    case ERROR_UNIT_BIT:
      return DoCorruptBit (p);
    default:
      NS_ASSERT_MSG (false, "m_unit not supported yet");
      break;
    }
  return false;
}

bool
RateErrorModel::DoCorruptPkt (Ptr<Packet> p)
{
  NS_LOG_FUNCTION_NOARGS ();
  return (m_ranvar.GetValue () < m_rate);
}

bool
RateErrorModel::DoCorruptByte (Ptr<Packet> p)
{
  NS_LOG_FUNCTION_NOARGS ();
  // compute pkt error rate, assume uniformly distributed byte error
  double per = 1 - pow (1.0 - m_rate, p->GetSize ());
  return (m_ranvar.GetValue () < per);
}

bool
RateErrorModel::DoCorruptBit (Ptr<Packet> p)
{
  NS_LOG_FUNCTION_NOARGS ();
  // compute pkt error rate, assume uniformly distributed bit error
  double per = 1 - pow (1.0 - m_rate, (8 * p->GetSize ()) );
  return (m_ranvar.GetValue () < per);
}

void 
RateErrorModel::DoReset (void) 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  /* re-initialize any state; no-op for now */ 
}

//
// ListErrorModel
//

NS_OBJECT_ENSURE_REGISTERED (ListErrorModel);

TypeId ListErrorModel::GetTypeId (void)
{ 
  static TypeId tid = TypeId ("ns3::ListErrorModel")
    .SetParent<ErrorModel> ()
    .AddConstructor<ListErrorModel> ()
  ;
  return tid;
}

ListErrorModel::ListErrorModel ()
{
  NS_LOG_FUNCTION_NOARGS ();
}

ListErrorModel::~ListErrorModel () 
{
  NS_LOG_FUNCTION_NOARGS ();
}

std::list<uint32_t> 
ListErrorModel::GetList (void) const 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  return m_packetList; 
}

void 
ListErrorModel::SetList (const std::list<uint32_t> &packetlist)
{ 
  NS_LOG_FUNCTION_NOARGS ();
  m_packetList = packetlist;
}

// When performance becomes a concern, the list provided could be 
// converted to a dynamically-sized array of uint32_t to avoid 
// list iteration below.
bool 
ListErrorModel::DoCorrupt (Ptr<Packet> p) 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  if (!IsEnabled ())
    {
      return false;
    }
  uint32_t uid = p->GetUid ();
  for (PacketListCI i = m_packetList.begin (); 
       i != m_packetList.end (); i++)
    {
      if (uid == *i)
        {
          return true;
        }
    }
  return false;
}

void 
ListErrorModel::DoReset (void) 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  m_packetList.clear ();
}

//
// ReceiveListErrorModel
//

NS_OBJECT_ENSURE_REGISTERED (ReceiveListErrorModel);

TypeId ReceiveListErrorModel::GetTypeId (void)
{ 
  static TypeId tid = TypeId ("ns3::ReceiveListErrorModel")
    .SetParent<ErrorModel> ()
    .AddConstructor<ReceiveListErrorModel> ()
  ;
  return tid;
}


ReceiveListErrorModel::ReceiveListErrorModel () :
  m_timesInvoked (0)
{
  NS_LOG_FUNCTION_NOARGS ();
}

ReceiveListErrorModel::~ReceiveListErrorModel () 
{
  NS_LOG_FUNCTION_NOARGS ();
}

std::list<uint32_t> 
ReceiveListErrorModel::GetList (void) const 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  return m_packetList; 
}

void 
ReceiveListErrorModel::SetList (const std::list<uint32_t> &packetlist)
{ 
  NS_LOG_FUNCTION_NOARGS ();
  m_packetList = packetlist;
}

bool 
ReceiveListErrorModel::DoCorrupt (Ptr<Packet> p) 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  if (!IsEnabled ())
    {
      return false;
    }
  m_timesInvoked += 1;
  for (PacketListCI i = m_packetList.begin (); 
       i != m_packetList.end (); i++)
    {
      if (m_timesInvoked - 1 == *i)
        {
          return true;
        }
    }
  return false;
}

void 
ReceiveListErrorModel::DoReset (void) 
{ 
  NS_LOG_FUNCTION_NOARGS ();
  m_packetList.clear ();
}


} // namespace ns3