OW_AtomicOps.cpp

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#include "OW_config.h"
#include "OW_AtomicOps.hpp"

#if defined(OW_USE_PTHREAD_SPIN_LOCK_ATOMIC_OPS)

namespace OW_NAMESPACE
{

Atomic_t::Atomic_t()
   : val(0)
{
   pthread_spin_init(&spinlock, 0);
}
Atomic_t::Atomic_t(int i)
   : val(i)
{
   pthread_spin_init(&spinlock, 0);
}
void AtomicInc(Atomic_t &v)
{
   pthread_spin_lock(&v.spinlock);
   ++v.val;
   pthread_spin_unlock(&v.spinlock);
}
bool AtomicDecAndTest(Atomic_t &v)
{
   pthread_spin_lock(&v.spinlock);
   --v.val;
   bool b = ((v.val == 0) ? true : false) ;
   pthread_spin_unlock(&v.spinlock);
   return b;
}
int AtomicGet(Atomic_t const &v)
{
   return v.val;
}
void AtomicDec(Atomic_t &v)
{
   pthread_spin_lock(&v.spinlock);
   --v.val;
   pthread_spin_unlock(&v.spinlock);
}

} // end namespace OW_NAMESPACE

#elif defined(OW_USE_OW_DEFAULT_ATOMIC_OPS)
#include "OW_Mutex.hpp"
#include "OW_MutexLock.hpp"
#include "OW_ThreadOnce.hpp"

namespace OW_NAMESPACE
{

// this needs to be a pointer because of static initialization order conflicts.  
// It shouldn't ever be deleted b/c it may be referenced by a destructor of a 
// static variable that is being deleted.
static Mutex* guard = 0;
static OnceFlag g_once = OW_ONCE_INIT;
static void initGuard()
{
   guard = new Mutex();
}
void AtomicInc(Atomic_t &v)
{
   callOnce(g_once, initGuard);
   MutexLock lock(*guard);
   ++v.val;
}
bool AtomicDecAndTest(Atomic_t &v)
{
   callOnce(g_once, initGuard);
   MutexLock lock(*guard);
   return --v.val == 0;
}
int AtomicGet(Atomic_t const &v)
{
   callOnce(g_once, initGuard);
   MutexLock lock(*guard);
   return v.val;
}
void AtomicDec(Atomic_t &v)
{
   callOnce(g_once, initGuard);
   MutexLock lock(*guard);
   --v.val;
}

} // end namespace OW_NAMESPACE

#endif

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