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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@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 
inithb_mutex_t123   inline void init   (void) { hb_mutex_impl_init   (&m); }
lockhb_mutex_t124   inline void lock   (void) { hb_mutex_impl_lock   (&m); }
unlockhb_mutex_t125   inline void unlock (void) { hb_mutex_impl_unlock (&m); }
finishhb_mutex_t126   inline void finish (void) { hb_mutex_impl_finish (&m); }
127 };
128 
129 
130 #endif /* HB_MUTEX_PRIVATE_HH */
131