Mutex.h

/**
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*   /___/ __ \/ __ \/ __ \/ ___/ _ \/ ___/ ___/ / / / _ \
*  / / / /_/ / /_/ / /_/ / /  /  __(__  ) /__/ /_/ /  __/
* /_/  \____/_.___/\____/_/   \___/____/\___/\__,_/\___/
*
*
* @file Mutex.h
* @date Created: 16-4-2015
* @version 1.0
*
* @author Nathan Schaaphuizen
*
* @section LICENSE
* License: newBSD
*
* Copyright © 2015, HU University of Applied Sciences Utrecht.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
* - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
* - 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.
* - Neither the name of the HU University of Applied Sciences Utrecht nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 HU UNIVERSITY OF APPLIED SCIENCES UTRECHT
* 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.
**/

#ifndef _MUTEX_H
#define _MUTEX_H


/// @brief Class for synchronisation between cogs.
///
/// The Mutex class provides simple synchronisation between cogs
/// using a binary semaphore.
/// The mutex can either be locked or unlocked and does not hold a owner.
/// This means that it cannot be used recursively.
class Mutex{
private:
  volatile bool semaphore;

public:
 
  /// @brief Create new Mutex object.
  Mutex();
  
  /// @brief Claim the mutex.
  ///
  /// This function blocks if the mutex is already claimed.
  void claim() volatile;
  
  /// @brief Free the mutex.
  void signal() volatile; 
  
};  

#endif // _MUTEX_H