spin_lock.h

/*****************************************************/
/* lean Concurrent              (c) Tobias Zirr 2011 */
/*****************************************************/

#ifndef LEAN_CONCURRENT_SPINLOCK
#define LEAN_CONCURRENT_SPINLOCK

#include "../lean.h"
#include "../tags/noncopyable.h"
#include "atomic.h"

// Include automatically to encourage use of scoped_lock
#include "../smart/scoped_lock.h"

namespace lean
{
namespace concurrent
{

template <class Counter = long>
class spin_lock : public noncopyable
{
private:
    Counter m_counter;

public:
    spin_lock()
        : m_counter(0) {  }

    LEAN_INLINE bool try_lock()
    {
        return atomic_test_and_set(m_counter, static_cast<Counter>(0), static_cast<Counter>(1));
    }

    LEAN_INLINE void lock()
    {
        while (!try_lock());
    }

    LEAN_INLINE void unlock()
    {
        atomic_test_and_set(m_counter, static_cast<Counter>(1), static_cast<Counter>(0));
    }
};

typedef smart::scoped_lock< spin_lock<> > scoped_sl_lock;

} // namespace

using concurrent::spin_lock;

using concurrent::scoped_sl_lock;

} // namespace

#endif