/******************************************************
The interface to the operating system synchronization primitives.

(c) 1995 Innobase Oy

Created 9/6/1995 Heikki Tuuri
*******************************************************/

#ifdef __WIN__
#include <winbase.h>
#endif

/**************************************************************
Acquires ownership of a fast mutex. Currently in Windows this is the same
as os_fast_mutex_lock! */
UNIV_INLINE
ulint
os_fast_mutex_trylock(
/*==================*/
						/* out: 0 if success, != 0 if
						was reserved by another
						thread */
	os_fast_mutex_t*	fast_mutex)	/* in: mutex to acquire */
{
#ifdef __WIN__
	EnterCriticalSection(fast_mutex);

	return(0);
#else
#if defined(UNIV_HOTBACKUP) && defined(UNIV_HPUX10)
	/* Since the hot backup version is standalone, MySQL does not redefine
	pthread_mutex_trylock for HP-UX-10.20, and consequently we must invert
	the return value here */

	return((ulint) (1 - pthread_mutex_trylock(fast_mutex)));
#else
	/* NOTE that the MySQL my_pthread.h redefines pthread_mutex_trylock
	so that it returns 0 on success. In the operating system
	libraries, HP-UX-10.20 follows the old Posix 1003.4a Draft 4 and
	returns 1 on success (but MySQL remaps that to 0), while Linux,
	FreeBSD, Solaris, AIX, Tru64 Unix, HP-UX-11.0 return 0 on success. */

	return((ulint) pthread_mutex_trylock(fast_mutex));
#endif
#endif
}

#ifdef UNIV_SYNC_ATOMIC
/**************************************************************
Atomic compare-and-swap for InnoDB. Currently requires GCC atomic builtins
or Solaris atomic_* functions. */
UNIV_INLINE
ibool
os_compare_and_swap(
/*================*/
					/* out: true if swapped */
	volatile lint* 	ptr,		/* in: pointer to target */
	lint		oldVal,		/* in: value to compare to */
	lint		newVal)		/* in: value to swap in */
{
#ifdef HAVE_GCC_ATOMIC_BUILTINS
	return (__sync_bool_compare_and_swap(ptr, oldVal, newVal));
#elif HAVE_SOLARIS_ATOMIC
	lint retVal = (lint)atomic_cas_ulong((volatile ulong_t *)ptr,
		oldVal, newVal);
	return (retVal == oldVal);
#elif WIN_ATOMICS32
        lint retVal = (lint)InterlockedCompareExchange(ptr, newVal, oldVal);
        return (retVal == oldVal);
#elif WIN_ATOMICS64
        lint retVal = (lint)InterlockedCompareExchange64(ptr, newVal, oldVal);
        return (retVal == oldVal);
#else
#error "Need support for atomic ops"
#endif
}

/**************************************************************
Memory barrier for load */
UNIV_INLINE
void
os_memory_barrier_load()
{
#ifdef HAVE_GCC_ATOMIC_BUILTINS
  __sync_synchronize();
#elif HAVE_SOLARIS_ATOMIC
  membar_consumer();
#elif WIN_ATOMICS32
  MemoryBarrier();
#elif WIN_ATOMICS64
  MemoryBarrier();
#endif
}

/**************************************************************
Memory barrier for store */
UNIV_INLINE
void
os_memory_barrier_store()
{
#ifdef HAVE_GCC_ATOMIC_BUILTINS
  __sync_synchronize();
#elif HAVE_SOLARIS_ATOMIC
  membar_producer();
#elif WIN_ATOMICS32
  MemoryBarrier();
#elif WIN_ATOMICS64
  MemoryBarrier();
#endif
}

/**************************************************************
Memory barrier */
UNIV_INLINE
void
os_memory_barrier()
{
#ifdef HAVE_GCC_ATOMIC_BUILTINS
  __sync_synchronize();
#elif HAVE_SOLARIS_ATOMIC
  membar_enter();
#elif WIN_ATOMICS32
  MemoryBarrier();
#elif WIN_ATOMICS64
  MemoryBarrier();
#endif
}


/**************************************************************
Atomic increment for InnoDB. Currently requires GCC atomic builtins. */
UNIV_INLINE
lint
os_atomic_increment(
/*================*/
					/* out: resulting value */
	volatile lint*	ptr,		/* in: pointer to target */
	lint		amount)		/* in: amount of increment */
{
#ifdef HAVE_GCC_ATOMIC_BUILTINS
	return (__sync_add_and_fetch(ptr, amount));
#elif HAVE_SOLARIS_ATOMIC
	return ((lint)atomic_add_long_nv((volatile ulong_t *)ptr, amount));
#elif WIN_ATOMICS32
        return ((lint)InterlockedExchangeAdd(ptr, amount) + amount);
#elif WIN_ATOMICS64
        return ((lint)InterlockedExchangeAdd64(ptr, amount) + amount);
#else
#error "Need support for atomic ops"
#endif
}
#endif /* UNIV_SYNC_ATOMIC */