SpinLock.h

Go to the documentation of this file.

// this is for emacs file handling -*- mode: c++; indent-tabs-mode: nil -*-

// -- BEGIN LICENSE BLOCK ----------------------------------------------
// This file is part of FZIs ic_workspace.
//
// This program is free software licensed under the LGPL
// (GNU LESSER GENERAL PUBLIC LICENSE Version 3).
// You can find a copy of this license in LICENSE folder in the top
// directory of the source code.
//
// © Copyright 2016 FZI Forschungszentrum Informatik, Karlsruhe, Germany
//
// -- END LICENSE BLOCK ------------------------------------------------

//----------------------------------------------------------------------
//----------------------------------------------------------------------
#ifndef ICL_CORE_THREAD_SPIN_LOCK_H_INCLUDED
#define ICL_CORE_THREAD_SPIN_LOCK_H_INCLUDED

#include <boost/atomic.hpp>

namespace icl_core {
namespace thread {

class SpinLock
{
public:
  SpinLock()
    : m_state(UNLOCKED)
  { }

  bool lock()
  {
    while (m_state.exchange(LOCKED, boost::memory_order_acquire) == LOCKED)
    {
      // busy-wait
    }
    return true;
  }

  bool tryLock()
  {
    return (m_state.exchange(LOCKED, boost::memory_order_acquire) == LOCKED);
  }

  void unlock()
  {
    m_state.store(UNLOCKED, boost::memory_order_release);
  }

private:
  enum LockState
  {
    LOCKED,
    UNLOCKED
  };

  boost::atomic<LockState> m_state;
};

}
}

#endif