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/*
//
// Copyright 1997-2009 Torsten Rohlfing
//
// Copyright 2004-2011 SRI International
//
// This file is part of the Computational Morphometry Toolkit.
//
// http://www.nitrc.org/projects/cmtk/
//
// The Computational Morphometry Toolkit is free software: you can
// redistribute it and/or modify it under the terms of the GNU General Public
// License as published by the Free Software Foundation, either version 3 of
// the License, or (at your option) any later version.
//
// The Computational Morphometry Toolkit 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 the Computational Morphometry Toolkit. If not, see
// <http://www.gnu.org/licenses/>.
//
// $Revision: 5436 $
//
// $LastChangedDate: 2018-12-10 19:01:20 -0800 (Mon, 10 Dec 2018) $
//
// $LastChangedBy: torstenrohlfing $
//
*/
#ifndef __cmtkSafeCounterMutex_h_included_
#define __cmtkSafeCounterMutex_h_included_
#include <cmtkconfig.h>
#include <System/cmtkMutexLock.h>
#include <System/cmtkLockingPtr.h>
namespace
cmtk
{
/** \addtogroup System */
//@{
/** Thread-safe counter using POSIX mutex lock.
* If the library is compiled without SMP support, then this class implements
* only an interface to a simple unsigned int counter. With SMP support, a
* mutex lock supplied by the MutexLock class is used to protect the
* counter from concurrent access of multiple threads.
*/
class SafeCounterMutex
{
public:
/// Constructor.
SafeCounterMutex( const unsigned int counter = 0 ) : m_Counter( counter ) {}
/// Retrieve counter value.
unsigned int Get() const
{
LockingPtr<const unsigned int> counter( this->m_Counter, this->m_Mutex );
return *counter;
}
/// Increment and return new counter value.
unsigned int Increment()
{
LockingPtr<unsigned int> counter( this->m_Counter, this->m_Mutex );
return ++(*counter);
}
/// Decrement and return new counter value.
unsigned int Decrement()
{
LockingPtr<unsigned int> counter( this->m_Counter, this->m_Mutex );
return --(*counter);
}
private:
/// The actual counter.
unsigned int m_Counter;
/// Mutex for thread-safe exclusive access to counter.
mutable MutexLock m_Mutex;
};
//@}
} // namespace cmtk
#endif // #ifndef __cmtkSafeCounterMutex_h_included_
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