This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
SDL_syssem.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
/*
Simple DirectMedia Layer
Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_config.h"
#include <errno.h>
#include <pthread.h>
#include <semaphore.h>
#include "SDL_thread.h"
#include "SDL_timer.h"
/* Wrapper around POSIX 1003.1b semaphores */
#if defined(__MACOSX__) || defined(__IPHONEOS__)
/* Mac OS X doesn't support sem_getvalue() as of version 10.4 */
#include "../generic/SDL_syssem.c"
#else
struct SDL_semaphore
{
sem_t sem;
};
/* Create a semaphore, initialized with value */
SDL_sem *
SDL_CreateSemaphore(Uint32 initial_value)
{
SDL_sem *sem = (SDL_sem *) SDL_malloc(sizeof(SDL_sem));
if (sem) {
if (sem_init(&sem->sem, 0, initial_value) < 0) {
SDL_SetError("sem_init() failed");
SDL_free(sem);
sem = NULL;
}
} else {
SDL_OutOfMemory();
}
return sem;
}
void
SDL_DestroySemaphore(SDL_sem * sem)
{
if (sem) {
sem_destroy(&sem->sem);
SDL_free(sem);
}
}
int
SDL_SemTryWait(SDL_sem * sem)
{
int retval;
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
retval = SDL_MUTEX_TIMEDOUT;
if (sem_trywait(&sem->sem) == 0) {
retval = 0;
}
return retval;
}
int
SDL_SemWait(SDL_sem * sem)
{
int retval;
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
retval = sem_wait(&sem->sem);
if (retval < 0) {
SDL_SetError("sem_wait() failed");
}
return retval;
}
int
SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
{
int retval;
struct timeval now;
struct timespec ts_timeout;
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
/* Try the easy cases first */
if (timeout == 0) {
return SDL_SemTryWait(sem);
}
if (timeout == SDL_MUTEX_MAXWAIT) {
return SDL_SemWait(sem);
}
/* Setup the timeout. sem_timedwait doesn't wait for
* a lapse of time, but until we reach a certain time.
* This time is now plus the timeout.
*/
gettimeofday(&now, NULL);
/* Add our timeout to current time */
now.tv_usec += (timeout % 1000) * 1000;
now.tv_sec += timeout / 1000;
/* Wrap the second if needed */
if ( now.tv_usec >= 1000000 ) {
now.tv_usec -= 1000000;
now.tv_sec ++;
}
/* Convert to timespec */
ts_timeout.tv_sec = now.tv_sec;
ts_timeout.tv_nsec = now.tv_usec * 1000;
/* Wait. */
do {
retval = sem_timedwait(&sem->sem, &ts_timeout);
} while (retval < 0 && errno == EINTR);
if (retval < 0) {
SDL_SetError("sem_timedwait() failed");
}
return retval;
}
Uint32
SDL_SemValue(SDL_sem * sem)
{
int ret = 0;
if (sem) {
sem_getvalue(&sem->sem, &ret);
if (ret < 0) {
ret = 0;
}
}
return (Uint32) ret;
}
int
SDL_SemPost(SDL_sem * sem)
{
int retval;
if (!sem) {
SDL_SetError("Passed a NULL semaphore");
return -1;
}
retval = sem_post(&sem->sem);
if (retval < 0) {
SDL_SetError("sem_post() failed");
}
return retval;
}
#endif /* __MACOSX__ */
/* vi: set ts=4 sw=4 expandtab: */