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 /*

  * Copyright © 2007  Chris Wilson

  * Copyright © 2009,2010  Red Hat, Inc.

  * Copyright © 2011,2012  Google, Inc.

  *

  *  This is part of HarfBuzz, a text shaping library.

  *

  * Permission is hereby granted, without written agreement and without

  * license or royalty fees, to use, copy, modify, and distribute this

  * software and its documentation for any purpose, provided that the

  * above copyright notice and the following two paragraphs appear in

  * all copies of this software.

  *

  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

  * DAMAGE.

  *

  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

  *

  * Contributor(s):

  *	Chris Wilson <chris@chris-wilson.co.uk>

  * Red Hat Author(s): Behdad Esfahbod

  * Google Author(s): Behdad Esfahbod

  */

 #ifndef HB_MUTEX_PRIVATE_HH

 #define HB_MUTEX_PRIVATE_HH

 #include "hb-private.hh"

 /* mutex */

 /* We need external help for these */

 #if 0

 #elif !defined(HB_NO_MT) && (defined(_WIN32) || defined(__CYGWIN__))

 #define WIN32_LEAN_AND_MEAN

 #include <windows.h>

 typedef CRITICAL_SECTION hb_mutex_impl_t;

 #define HB_MUTEX_IMPL_INIT	{ NULL, 0, 0, NULL, NULL, 0 }

 #define hb_mutex_impl_init(M)	InitializeCriticalSection (M)

 #define hb_mutex_impl_lock(M)	EnterCriticalSection (M)

 #define hb_mutex_impl_unlock(M)	LeaveCriticalSection (M)

 #define hb_mutex_impl_finish(M)	DeleteCriticalSection (M)

 #elif !defined(HB_NO_MT) && (defined(HAVE_PTHREAD) || defined(__APPLE__))

 #include <pthread.h>

 typedef pthread_mutex_t hb_mutex_impl_t;

 #define HB_MUTEX_IMPL_INIT	PTHREAD_MUTEX_INITIALIZER

 #define hb_mutex_impl_init(M)	pthread_mutex_init (M, NULL)

 #define hb_mutex_impl_lock(M)	pthread_mutex_lock (M)

 #define hb_mutex_impl_unlock(M)	pthread_mutex_unlock (M)

 #define hb_mutex_impl_finish(M)	pthread_mutex_destroy (M)

 #elif !defined(HB_NO_MT) && defined(HAVE_INTEL_ATOMIC_PRIMITIVES)

 #if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)

 # include <sched.h>

 # define HB_SCHED_YIELD() sched_yield ()

 #else

 # define HB_SCHED_YIELD() HB_STMT_START {} HB_STMT_END

 #endif

 /* This actually is not a totally awful implementation. */

 typedef volatile int hb_mutex_impl_t;

 #define HB_MUTEX_IMPL_INIT	0

 #define hb_mutex_impl_init(M)	*(M) = 0

 #define hb_mutex_impl_lock(M)	HB_STMT_START { while (__sync_lock_test_and_set((M), 1)) HB_SCHED_YIELD (); } HB_STMT_END

 #define hb_mutex_impl_unlock(M)	__sync_lock_release (M)

 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END

 #elif !defined(HB_NO_MT)

 #if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)

 # include <sched.h>

 # define HB_SCHED_YIELD() sched_yield ()

 #else

 # define HB_SCHED_YIELD() HB_STMT_START {} HB_STMT_END

 #endif

 #define HB_MUTEX_INT_NIL 1 /* Warn that fallback implementation is in use. */

 typedef volatile int hb_mutex_impl_t;

 #define HB_MUTEX_IMPL_INIT	0

 #define hb_mutex_impl_init(M)	*(M) = 0

 #define hb_mutex_impl_lock(M)	HB_STMT_START { while (*(M)) HB_SCHED_YIELD (); (*(M))++; } HB_STMT_END

 #define hb_mutex_impl_unlock(M)	(*(M))--;

 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END

 #else /* HB_NO_MT */

 typedef int hb_mutex_impl_t;

 #define HB_MUTEX_IMPL_INIT	0

 #define hb_mutex_impl_init(M)	HB_STMT_START {} HB_STMT_END

 #define hb_mutex_impl_lock(M)	HB_STMT_START {} HB_STMT_END

 #define hb_mutex_impl_unlock(M)	HB_STMT_START {} HB_STMT_END

 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END

 #endif

 #define HB_MUTEX_INIT		{HB_MUTEX_IMPL_INIT}

 struct hb_mutex_t

 {

   /* TODO Add tracing. */

   hb_mutex_impl_t m;

   inline void init   (void) { hb_mutex_impl_init   (&m); }

   inline void lock   (void) { hb_mutex_impl_lock   (&m); }

   inline void unlock (void) { hb_mutex_impl_unlock (&m); }

   inline void finish (void) { hb_mutex_impl_finish (&m); }

 };

 #endif /* HB_MUTEX_PRIVATE_HH */