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      1 /*
      2  * Copyright  2007  Chris Wilson
      3  * Copyright  2009,2010  Red Hat, Inc.
      4  * Copyright  2011,2012  Google, Inc.
      5  *
      6  *  This is part of HarfBuzz, a text shaping library.
      7  *
      8  * Permission is hereby granted, without written agreement and without
      9  * license or royalty fees, to use, copy, modify, and distribute this
     10  * software and its documentation for any purpose, provided that the
     11  * above copyright notice and the following two paragraphs appear in
     12  * all copies of this software.
     13  *
     14  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
     15  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
     16  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
     17  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
     18  * DAMAGE.
     19  *
     20  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
     21  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
     22  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
     23  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
     24  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
     25  *
     26  * Contributor(s):
     27  *	Chris Wilson <chris (at) chris-wilson.co.uk>
     28  * Red Hat Author(s): Behdad Esfahbod
     29  * Google Author(s): Behdad Esfahbod
     30  */
     31 
     32 #ifndef HB_MUTEX_PRIVATE_HH
     33 #define HB_MUTEX_PRIVATE_HH
     34 
     35 #include "hb-private.hh"
     36 
     37 
     38 /* mutex */
     39 
     40 /* We need external help for these */
     41 
     42 #if 0
     43 
     44 
     45 #elif !defined(HB_NO_MT) && (defined(_WIN32) || defined(__CYGWIN__))
     46 
     47 #define WIN32_LEAN_AND_MEAN
     48 #include <windows.h>
     49 typedef CRITICAL_SECTION hb_mutex_impl_t;
     50 #define HB_MUTEX_IMPL_INIT	{ NULL, 0, 0, NULL, NULL, 0 }
     51 #define hb_mutex_impl_init(M)	InitializeCriticalSection (M)
     52 #define hb_mutex_impl_lock(M)	EnterCriticalSection (M)
     53 #define hb_mutex_impl_unlock(M)	LeaveCriticalSection (M)
     54 #define hb_mutex_impl_finish(M)	DeleteCriticalSection (M)
     55 
     56 
     57 #elif !defined(HB_NO_MT) && (defined(HAVE_PTHREAD) || defined(__APPLE__))
     58 
     59 #include <pthread.h>
     60 typedef pthread_mutex_t hb_mutex_impl_t;
     61 #define HB_MUTEX_IMPL_INIT	PTHREAD_MUTEX_INITIALIZER
     62 #define hb_mutex_impl_init(M)	pthread_mutex_init (M, NULL)
     63 #define hb_mutex_impl_lock(M)	pthread_mutex_lock (M)
     64 #define hb_mutex_impl_unlock(M)	pthread_mutex_unlock (M)
     65 #define hb_mutex_impl_finish(M)	pthread_mutex_destroy (M)
     66 
     67 
     68 #elif !defined(HB_NO_MT) && defined(HAVE_INTEL_ATOMIC_PRIMITIVES)
     69 
     70 #if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)
     71 # include <sched.h>
     72 # define HB_SCHED_YIELD() sched_yield ()
     73 #else
     74 # define HB_SCHED_YIELD() HB_STMT_START {} HB_STMT_END
     75 #endif
     76 
     77 /* This actually is not a totally awful implementation. */
     78 typedef volatile int hb_mutex_impl_t;
     79 #define HB_MUTEX_IMPL_INIT	0
     80 #define hb_mutex_impl_init(M)	*(M) = 0
     81 #define hb_mutex_impl_lock(M)	HB_STMT_START { while (__sync_lock_test_and_set((M), 1)) HB_SCHED_YIELD (); } HB_STMT_END
     82 #define hb_mutex_impl_unlock(M)	__sync_lock_release (M)
     83 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END
     84 
     85 
     86 #elif !defined(HB_NO_MT)
     87 
     88 #if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)
     89 # include <sched.h>
     90 # define HB_SCHED_YIELD() sched_yield ()
     91 #else
     92 # define HB_SCHED_YIELD() HB_STMT_START {} HB_STMT_END
     93 #endif
     94 
     95 #define HB_MUTEX_INT_NIL 1 /* Warn that fallback implementation is in use. */
     96 typedef volatile int hb_mutex_impl_t;
     97 #define HB_MUTEX_IMPL_INIT	0
     98 #define hb_mutex_impl_init(M)	*(M) = 0
     99 #define hb_mutex_impl_lock(M)	HB_STMT_START { while (*(M)) HB_SCHED_YIELD (); (*(M))++; } HB_STMT_END
    100 #define hb_mutex_impl_unlock(M)	(*(M))--;
    101 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END
    102 
    103 
    104 #else /* HB_NO_MT */
    105 
    106 typedef int hb_mutex_impl_t;
    107 #define HB_MUTEX_IMPL_INIT	0
    108 #define hb_mutex_impl_init(M)	HB_STMT_START {} HB_STMT_END
    109 #define hb_mutex_impl_lock(M)	HB_STMT_START {} HB_STMT_END
    110 #define hb_mutex_impl_unlock(M)	HB_STMT_START {} HB_STMT_END
    111 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END
    112 
    113 #endif
    114 
    115 
    116 #define HB_MUTEX_INIT		{HB_MUTEX_IMPL_INIT}
    117 struct hb_mutex_t
    118 {
    119   /* TODO Add tracing. */
    120 
    121   hb_mutex_impl_t m;
    122 
    123   inline void init   (void) { hb_mutex_impl_init   (&m); }
    124   inline void lock   (void) { hb_mutex_impl_lock   (&m); }
    125   inline void unlock (void) { hb_mutex_impl_unlock (&m); }
    126   inline void finish (void) { hb_mutex_impl_finish (&m); }
    127 };
    128 
    129 
    130 #endif /* HB_MUTEX_PRIVATE_HH */
    131