1 /*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20 */
21 #include "../../SDL_internal.h"
22
23 #include <sys/time.h>
24 #include <time.h>
25 #include <unistd.h>
26 #include <errno.h>
27 #include <pthread.h>
28
29 #include "SDL_thread.h"
30 #include "SDL_sysmutex_c.h"
31
32 struct SDL_cond
33 {
34 pthread_cond_t cond;
35 };
36
37 /* Create a condition variable */
38 SDL_cond *
SDL_CreateCond(void)39 SDL_CreateCond(void)
40 {
41 SDL_cond *cond;
42
43 cond = (SDL_cond *) SDL_malloc(sizeof(SDL_cond));
44 if (cond) {
45 if (pthread_cond_init(&cond->cond, NULL) < 0) {
46 SDL_SetError("pthread_cond_init() failed");
47 SDL_free(cond);
48 cond = NULL;
49 }
50 }
51 return (cond);
52 }
53
54 /* Destroy a condition variable */
55 void
SDL_DestroyCond(SDL_cond * cond)56 SDL_DestroyCond(SDL_cond * cond)
57 {
58 if (cond) {
59 pthread_cond_destroy(&cond->cond);
60 SDL_free(cond);
61 }
62 }
63
64 /* Restart one of the threads that are waiting on the condition variable */
65 int
SDL_CondSignal(SDL_cond * cond)66 SDL_CondSignal(SDL_cond * cond)
67 {
68 int retval;
69
70 if (!cond) {
71 return SDL_SetError("Passed a NULL condition variable");
72 }
73
74 retval = 0;
75 if (pthread_cond_signal(&cond->cond) != 0) {
76 return SDL_SetError("pthread_cond_signal() failed");
77 }
78 return retval;
79 }
80
81 /* Restart all threads that are waiting on the condition variable */
82 int
SDL_CondBroadcast(SDL_cond * cond)83 SDL_CondBroadcast(SDL_cond * cond)
84 {
85 int retval;
86
87 if (!cond) {
88 return SDL_SetError("Passed a NULL condition variable");
89 }
90
91 retval = 0;
92 if (pthread_cond_broadcast(&cond->cond) != 0) {
93 return SDL_SetError("pthread_cond_broadcast() failed");
94 }
95 return retval;
96 }
97
98 int
SDL_CondWaitTimeout(SDL_cond * cond,SDL_mutex * mutex,Uint32 ms)99 SDL_CondWaitTimeout(SDL_cond * cond, SDL_mutex * mutex, Uint32 ms)
100 {
101 int retval;
102 #ifndef HAVE_CLOCK_GETTIME
103 struct timeval delta;
104 #endif
105 struct timespec abstime;
106
107 if (!cond) {
108 return SDL_SetError("Passed a NULL condition variable");
109 }
110
111 #ifdef HAVE_CLOCK_GETTIME
112 clock_gettime(CLOCK_REALTIME, &abstime);
113
114 abstime.tv_nsec += (ms % 1000) * 1000000;
115 abstime.tv_sec += ms / 1000;
116 #else
117 gettimeofday(&delta, NULL);
118
119 abstime.tv_sec = delta.tv_sec + (ms / 1000);
120 abstime.tv_nsec = (delta.tv_usec + (ms % 1000) * 1000) * 1000;
121 #endif
122 if (abstime.tv_nsec > 1000000000) {
123 abstime.tv_sec += 1;
124 abstime.tv_nsec -= 1000000000;
125 }
126
127 tryagain:
128 retval = pthread_cond_timedwait(&cond->cond, &mutex->id, &abstime);
129 switch (retval) {
130 case EINTR:
131 goto tryagain;
132 break;
133 case ETIMEDOUT:
134 retval = SDL_MUTEX_TIMEDOUT;
135 break;
136 case 0:
137 break;
138 default:
139 retval = SDL_SetError("pthread_cond_timedwait() failed");
140 }
141 return retval;
142 }
143
144 /* Wait on the condition variable, unlocking the provided mutex.
145 The mutex must be locked before entering this function!
146 */
147 int
SDL_CondWait(SDL_cond * cond,SDL_mutex * mutex)148 SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex)
149 {
150 if (!cond) {
151 return SDL_SetError("Passed a NULL condition variable");
152 } else if (pthread_cond_wait(&cond->cond, &mutex->id) != 0) {
153 return SDL_SetError("pthread_cond_wait() failed");
154 }
155 return 0;
156 }
157
158 /* vi: set ts=4 sw=4 expandtab: */
159