/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2008 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

 */

#include <pthread.h>

#include <cerrno> // for ETIMEDOUT

#include <sys/time.h>

#include "fatal-error.h"

#include "system-condition.h"

#include "log.h"

namespace ns3 {

NS_LOG_COMPONENT_DEFINE ("SystemCondition");

class SystemConditionPrivate {

public:

  /// Conversion from ns to s.

  static const uint64_t NS_PER_SEC = (uint64_t)1000000000;

  SystemConditionPrivate ();

  ~SystemConditionPrivate ();

  void SetCondition (bool condition);

  bool GetCondition (void);

  void Signal (void);

  void Broadcast (void);

  void Wait (void);

  bool TimedWait (uint64_t ns);

private:

  pthread_mutex_t m_mutex;

  pthread_cond_t  m_cond;

  bool m_condition;

};

SystemConditionPrivate::SystemConditionPrivate ()

{

  NS_LOG_FUNCTION (this);

  m_condition = false;

  pthread_mutexattr_t mAttr;

  pthread_mutexattr_init (&mAttr);

//

// Linux and OS X (at least) have, of course chosen different names for the 

// error checking flags just to make life difficult.

//

#if defined (PTHREAD_MUTEX_ERRORCHECK_NP)

  pthread_mutexattr_settype (&mAttr, PTHREAD_MUTEX_ERRORCHECK_NP);

#else

  pthread_mutexattr_settype (&mAttr, PTHREAD_MUTEX_ERRORCHECK);

#endif

  pthread_mutex_init (&m_mutex, &mAttr);

  pthread_condattr_t cAttr;

  pthread_condattr_init (&cAttr);

  pthread_condattr_setpshared (&cAttr, PTHREAD_PROCESS_PRIVATE);

  pthread_cond_init (&m_cond, &cAttr);

}

SystemConditionPrivate::~SystemConditionPrivate() 

{

  NS_LOG_FUNCTION (this);

  pthread_mutex_destroy (&m_mutex);

  pthread_cond_destroy (&m_cond);

}

void

SystemConditionPrivate::SetCondition (bool condition)

{

  NS_LOG_FUNCTION (this << condition);

  m_condition = condition;

}

bool

SystemConditionPrivate::GetCondition (void)

{

  NS_LOG_FUNCTION (this);

  return m_condition;

}

void

SystemConditionPrivate::Signal (void)

{

  NS_LOG_FUNCTION (this);

  pthread_mutex_lock (&m_mutex);

  pthread_cond_signal (&m_cond);

  pthread_mutex_unlock (&m_mutex);

}

void

SystemConditionPrivate::Broadcast (void)

{

  NS_LOG_FUNCTION (this);

  pthread_mutex_lock (&m_mutex);

  pthread_cond_broadcast (&m_cond);

  pthread_mutex_unlock (&m_mutex);

}

void

SystemConditionPrivate::Wait (void)

{

  NS_LOG_FUNCTION (this);

  pthread_mutex_lock (&m_mutex);

  m_condition = false;

  while (m_condition == false)

    {

      pthread_cond_wait (&m_cond, &m_mutex);

    }

  pthread_mutex_unlock (&m_mutex);

}

bool

SystemConditionPrivate::TimedWait (uint64_t ns)

{

  NS_LOG_FUNCTION (this << ns);

  struct timespec ts;

  ts.tv_sec = ns / NS_PER_SEC;

  ts.tv_nsec = ns % NS_PER_SEC;

  struct timeval tv;

  gettimeofday (&tv, NULL);

  ts.tv_sec += tv.tv_sec;

  ts.tv_nsec += tv.tv_usec * 1000;

  if (ts.tv_nsec > (int64_t)NS_PER_SEC)

    {

      ++ts.tv_sec;

      ts.tv_nsec %= NS_PER_SEC;

    }

  int rc;

  pthread_mutex_lock (&m_mutex);

  while (m_condition == false)

    {

      rc = pthread_cond_timedwait (&m_cond, &m_mutex, &ts);

      if (rc == ETIMEDOUT)

        {

          pthread_mutex_unlock (&m_mutex); 

          return true;

        }

    }

  pthread_mutex_unlock (&m_mutex);

  return false;

}

SystemCondition::SystemCondition() 

  : m_priv (new SystemConditionPrivate ())

{

  NS_LOG_FUNCTION (this);;

}

SystemCondition::~SystemCondition () 

{

  NS_LOG_FUNCTION (this);

  delete m_priv;

}

void

SystemCondition::SetCondition (bool condition) 

{

  NS_LOG_FUNCTION (this << condition);

  m_priv->SetCondition (condition);

}

bool

SystemCondition::GetCondition (void) 

{

  NS_LOG_FUNCTION (this);

  return m_priv->GetCondition ();

}

void

SystemCondition::Signal (void) 

{

  NS_LOG_FUNCTION (this);

  m_priv->Signal ();

}

void

SystemCondition::Broadcast (void) 

{

  NS_LOG_FUNCTION (this);

  m_priv->Broadcast ();

}

void

SystemCondition::Wait (void) 

{

  NS_LOG_FUNCTION (this);

  m_priv->Wait ();

}

bool

SystemCondition::TimedWait (uint64_t ns) 

{

  NS_LOG_FUNCTION (this << ns);

  return m_priv->TimedWait (ns);

}

} // namespace ns3