1 /*
2 * Atomic int and pointer operations. Originally copied from HarfBuzz.
3 *
4 * Copyright © 2007 Chris Wilson
5 * Copyright © 2009,2010 Red Hat, Inc.
6 * Copyright © 2011,2012,2013 Google, Inc.
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 _FCMUTEX_H_
33 #define _FCMUTEX_H_
34
35 #ifdef HAVE_CONFIG_H
36 #include <config.h>
37 #endif
38
39 #define FC_STMT_START do
40 #define FC_STMT_END while (0)
41
42 /* mutex */
43
44 /* We need external help for these */
45
46 #if 0
47
48
49 #elif !defined(FC_NO_MT) && defined(_MSC_VER) || defined(__MINGW32__)
50
51 #include "fcwindows.h"
52 typedef CRITICAL_SECTION fc_mutex_impl_t;
53 #define FC_MUTEX_IMPL_INIT { NULL, 0, 0, NULL, NULL, 0 }
54 #define fc_mutex_impl_init(M) InitializeCriticalSection (M)
55 #define fc_mutex_impl_lock(M) EnterCriticalSection (M)
56 #define fc_mutex_impl_unlock(M) LeaveCriticalSection (M)
57 #define fc_mutex_impl_finish(M) DeleteCriticalSection (M)
58
59
60 #elif !defined(FC_NO_MT) && (defined(HAVE_PTHREAD) || defined(__APPLE__))
61
62 #include <pthread.h>
63 typedef pthread_mutex_t fc_mutex_impl_t;
64 #define FC_MUTEX_IMPL_INIT PTHREAD_MUTEX_INITIALIZER
65 #define fc_mutex_impl_init(M) pthread_mutex_init (M, NULL)
66 #define fc_mutex_impl_lock(M) pthread_mutex_lock (M)
67 #define fc_mutex_impl_unlock(M) pthread_mutex_unlock (M)
68 #define fc_mutex_impl_finish(M) pthread_mutex_destroy (M)
69
70
71 #elif !defined(FC_NO_MT) && defined(HAVE_INTEL_ATOMIC_PRIMITIVES)
72
73 #if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)
74 # include <sched.h>
75 # define FC_SCHED_YIELD() sched_yield ()
76 #else
77 # define FC_SCHED_YIELD() FC_STMT_START {} FC_STMT_END
78 #endif
79
80 /* This actually is not a totally awful implementation. */
81 typedef volatile int fc_mutex_impl_t;
82 #define FC_MUTEX_IMPL_INIT 0
83 #define fc_mutex_impl_init(M) *(M) = 0
84 #define fc_mutex_impl_lock(M) FC_STMT_START { while (__sync_lock_test_and_set((M), 1)) FC_SCHED_YIELD (); } FC_STMT_END
85 #define fc_mutex_impl_unlock(M) __sync_lock_release (M)
86 #define fc_mutex_impl_finish(M) FC_STMT_START {} FC_STMT_END
87
88
89 #elif !defined(FC_NO_MT)
90
91 #if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)
92 # include <sched.h>
93 # define FC_SCHED_YIELD() sched_yield ()
94 #else
95 # define FC_SCHED_YIELD() FC_STMT_START {} FC_STMT_END
96 #endif
97
98 #define FC_MUTEX_INT_NIL 1 /* Warn that fallback implementation is in use. */
99 typedef volatile int fc_mutex_impl_t;
100 #define FC_MUTEX_IMPL_INIT 0
101 #define fc_mutex_impl_init(M) *(M) = 0
102 #define fc_mutex_impl_lock(M) FC_STMT_START { while (*(M)) FC_SCHED_YIELD (); (*(M))++; } FC_STMT_END
103 #define fc_mutex_impl_unlock(M) (*(M))--;
104 #define fc_mutex_impl_finish(M) FC_STMT_START {} FC_STMT_END
105
106
107 #else /* FC_NO_MT */
108
109 typedef int fc_mutex_impl_t;
110 #define FC_MUTEX_IMPL_INIT 0
111 #define fc_mutex_impl_init(M) FC_STMT_START {} FC_STMT_END
112 #define fc_mutex_impl_lock(M) FC_STMT_START {} FC_STMT_END
113 #define fc_mutex_impl_unlock(M) FC_STMT_START {} FC_STMT_END
114 #define fc_mutex_impl_finish(M) FC_STMT_START {} FC_STMT_END
115
116 #endif
117
118
119 #define FC_MUTEX_INIT {FC_MUTEX_IMPL_INIT}
120 typedef fc_mutex_impl_t FcMutex;
121 static inline void FcMutexInit (FcMutex *m) { fc_mutex_impl_init (m); }
122 static inline void FcMutexLock (FcMutex *m) { fc_mutex_impl_lock (m); }
123 static inline void FcMutexUnlock (FcMutex *m) { fc_mutex_impl_unlock (m); }
124 static inline void FcMutexFinish (FcMutex *m) { fc_mutex_impl_finish (m); }
125
126
127 #endif /* _FCMUTEX_H_ */