This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
/
SDL_syssem.c
217 lines (181 loc) · 4.1 KB
1
2
/*
SDL - Simple DirectMedia Layer
3
Copyright (C) 1997-2006 Sam Lantinga
4
5
This library is free software; you can redistribute it and/or
6
modify it under the terms of the GNU Lesser General Public
7
License as published by the Free Software Foundation; either
8
version 2.1 of the License, or (at your option) any later version.
9
10
11
12
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13
Lesser General Public License for more details.
14
15
16
17
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19
20
21
Sam Lantinga
slouken@libsdl.org
*/
22
#include "SDL_config.h"
23
24
/* RISC OS semiphores based on linux code */
25
26
27
28
29
30
#include "SDL_timer.h"
#include "SDL_thread.h"
#include "SDL_systhread_c.h"
31
#if !SDL_THREADS_DISABLED
32
33
SDL_sem *
34
SDL_CreateSemaphore(Uint32 initial_value)
35
{
36
SDL_SetError("SDL not configured with thread support");
37
return (SDL_sem *) 0;
38
39
}
40
void
41
SDL_DestroySemaphore(SDL_sem * sem)
42
{
43
return;
44
45
}
46
int
47
SDL_SemTryWait(SDL_sem * sem)
48
{
49
SDL_SetError("SDL not configured with thread support");
50
return -1;
51
52
}
53
int
54
SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
55
{
56
SDL_SetError("SDL not configured with thread support");
57
return -1;
58
59
}
60
int
61
SDL_SemWait(SDL_sem * sem)
62
{
63
SDL_SetError("SDL not configured with thread support");
64
return -1;
65
66
}
67
Uint32
68
SDL_SemValue(SDL_sem * sem)
69
{
70
return 0;
71
72
}
73
int
74
SDL_SemPost(SDL_sem * sem)
75
{
76
SDL_SetError("SDL not configured with thread support");
77
return -1;
78
79
80
81
}
#else
82
83
#include <unistd.h> /* For getpid() */
84
85
86
#include <pthread.h>
#include <semaphore.h>
87
88
89
90
struct SDL_semaphore
{
sem_t *sem;
sem_t sem_data;
91
92
};
93
/* Create a semaphore, initialized with value */
94
SDL_sem *
95
SDL_CreateSemaphore(Uint32 initial_value)
96
{
97
SDL_sem *sem = (SDL_sem *) SDL_malloc(sizeof(SDL_sem));
98
if (sem) {
99
100
101
if (sem_init(&sem->sem_data, 0, initial_value) < 0) {
SDL_SetError("sem_init() failed");
SDL_free(sem);
102
103
104
105
106
sem = NULL;
} else {
sem->sem = &sem->sem_data;
}
} else {
107
SDL_OutOfMemory();
108
109
}
return sem;
110
111
}
112
void
113
SDL_DestroySemaphore(SDL_sem * sem)
114
{
115
if (sem) {
116
117
sem_destroy(sem->sem);
SDL_free(sem);
118
}
119
120
}
121
int
122
SDL_SemTryWait(SDL_sem * sem)
123
{
124
125
126
int retval;
if (!sem) {
127
SDL_SetError("Passed a NULL semaphore");
128
129
130
return -1;
}
retval = SDL_MUTEX_TIMEDOUT;
131
if (sem_trywait(sem->sem) == 0) {
132
133
134
retval = 0;
}
return retval;
135
136
}
137
int
138
SDL_SemWait(SDL_sem * sem)
139
{
140
141
142
int retval;
if (!sem) {
143
SDL_SetError("Passed a NULL semaphore");
144
145
146
return -1;
}
147
retval = sem_wait(sem->sem);
148
if (retval < 0) {
149
SDL_SetError("sem_wait() failed");
150
151
}
return retval;
152
153
}
154
int
155
SDL_SemWaitTimeout(SDL_sem * sem, Uint32 timeout)
156
{
157
158
159
int retval;
if (!sem) {
160
SDL_SetError("Passed a NULL semaphore");
161
162
163
164
165
return -1;
}
/* Try the easy cases first */
if (timeout == 0) {
166
return SDL_SemTryWait(sem);
167
168
}
if (timeout == SDL_MUTEX_MAXWAIT) {
169
return SDL_SemWait(sem);
170
171
172
}
/* Ack! We have to busy wait... */
173
timeout += SDL_GetTicks();
174
do {
175
retval = SDL_SemTryWait(sem);
176
177
178
if (retval == 0) {
break;
}
179
SDL_Delay(1);
180
}
181
while (SDL_GetTicks() < timeout);
182
183
return retval;
184
185
}
186
Uint32
187
SDL_SemValue(SDL_sem * sem)
188
{
189
190
int ret = 0;
if (sem) {
191
sem_getvalue(sem->sem, &ret);
192
193
194
195
196
if (ret < 0) {
ret = 0;
}
}
return (Uint32) ret;
197
198
}
199
int
200
SDL_SemPost(SDL_sem * sem)
201
{
202
203
204
int retval;
if (!sem) {
205
SDL_SetError("Passed a NULL semaphore");
206
207
208
return -1;
}
209
retval = sem_post(sem->sem);
210
if (retval < 0) {
211
SDL_SetError("sem_post() failed");
212
213
}
return retval;
214
215
}
216
#endif /* !SDL_THREADS_DISABLED */
217
/* vi: set ts=4 sw=4 expandtab: */