e14743d1 |
1 | /* |
2 | SDL - Simple DirectMedia Layer |
3 | Copyright (C) 1997-2009 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 | This library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with this library; if not, write to the Free Software |
17 | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
18 | |
19 | Sam Lantinga |
20 | slouken@libsdl.org |
21 | */ |
22 | |
23 | #include <errno.h> |
24 | |
25 | #include "SDL_config.h" |
26 | |
27 | /* RISC OS semiphores based on linux code */ |
28 | |
29 | |
30 | #include "SDL_timer.h" |
31 | #include "SDL_thread.h" |
32 | #include "SDL_systhread_c.h" |
33 | |
34 | #if !SDL_THREADS_DISABLED |
35 | |
36 | SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) |
37 | { |
38 | SDL_SetError("SDL not configured with thread support"); |
39 | return (SDL_sem *)0; |
40 | } |
41 | |
42 | void SDL_DestroySemaphore(SDL_sem *sem) |
43 | { |
44 | return; |
45 | } |
46 | |
47 | int SDL_SemTryWait(SDL_sem *sem) |
48 | { |
49 | SDL_SetError("SDL not configured with thread support"); |
50 | return -1; |
51 | } |
52 | |
53 | int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) |
54 | { |
55 | SDL_SetError("SDL not configured with thread support"); |
56 | return -1; |
57 | } |
58 | |
59 | int SDL_SemWait(SDL_sem *sem) |
60 | { |
61 | SDL_SetError("SDL not configured with thread support"); |
62 | return -1; |
63 | } |
64 | |
65 | Uint32 SDL_SemValue(SDL_sem *sem) |
66 | { |
67 | return 0; |
68 | } |
69 | |
70 | int SDL_SemPost(SDL_sem *sem) |
71 | { |
72 | SDL_SetError("SDL not configured with thread support"); |
73 | return -1; |
74 | } |
75 | |
76 | #else |
77 | |
78 | |
79 | #include <unistd.h> /* For getpid() */ |
80 | #include <pthread.h> |
81 | #include <semaphore.h> |
82 | |
83 | struct SDL_semaphore { |
84 | sem_t *sem; |
85 | sem_t sem_data; |
86 | }; |
87 | |
88 | /* Create a semaphore, initialized with value */ |
89 | SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) |
90 | { |
91 | SDL_sem *sem = (SDL_sem *) SDL_malloc(sizeof(SDL_sem)); |
92 | if ( sem ) { |
93 | if ( sem_init(&sem->sem_data, 0, initial_value) < 0 ) { |
94 | SDL_SetError("sem_init() failed"); |
95 | SDL_free(sem); |
96 | sem = NULL; |
97 | } else { |
98 | sem->sem = &sem->sem_data; |
99 | } |
100 | } else { |
101 | SDL_OutOfMemory(); |
102 | } |
103 | return sem; |
104 | } |
105 | |
106 | void SDL_DestroySemaphore(SDL_sem *sem) |
107 | { |
108 | if ( sem ) { |
109 | sem_destroy(sem->sem); |
110 | SDL_free(sem); |
111 | } |
112 | } |
113 | |
114 | int SDL_SemTryWait(SDL_sem *sem) |
115 | { |
116 | int retval; |
117 | |
118 | if ( ! sem ) { |
119 | SDL_SetError("Passed a NULL semaphore"); |
120 | return -1; |
121 | } |
122 | retval = SDL_MUTEX_TIMEDOUT; |
123 | if ( sem_trywait(sem->sem) == 0 ) { |
124 | retval = 0; |
125 | } |
126 | return retval; |
127 | } |
128 | |
129 | int SDL_SemWait(SDL_sem *sem) |
130 | { |
131 | int retval; |
132 | |
133 | if ( ! sem ) { |
134 | SDL_SetError("Passed a NULL semaphore"); |
135 | return -1; |
136 | } |
137 | |
138 | while ( ((retval = sem_wait(sem->sem)) == -1) && (errno == EINTR) ) {} |
139 | if ( retval < 0 ) { |
140 | SDL_SetError("sem_wait() failed"); |
141 | } |
142 | return retval; |
143 | } |
144 | |
145 | int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) |
146 | { |
147 | int retval; |
148 | |
149 | if ( ! sem ) { |
150 | SDL_SetError("Passed a NULL semaphore"); |
151 | return -1; |
152 | } |
153 | |
154 | /* Try the easy cases first */ |
155 | if ( timeout == 0 ) { |
156 | return SDL_SemTryWait(sem); |
157 | } |
158 | if ( timeout == SDL_MUTEX_MAXWAIT ) { |
159 | return SDL_SemWait(sem); |
160 | } |
161 | |
162 | /* Ack! We have to busy wait... */ |
163 | timeout += SDL_GetTicks(); |
164 | do { |
165 | retval = SDL_SemTryWait(sem); |
166 | if ( retval == 0 ) { |
167 | break; |
168 | } |
169 | SDL_Delay(1); |
170 | } while ( SDL_GetTicks() < timeout ); |
171 | |
172 | return retval; |
173 | } |
174 | |
175 | Uint32 SDL_SemValue(SDL_sem *sem) |
176 | { |
177 | int ret = 0; |
178 | if ( sem ) { |
179 | sem_getvalue(sem->sem, &ret); |
180 | if ( ret < 0 ) { |
181 | ret = 0; |
182 | } |
183 | } |
184 | return (Uint32)ret; |
185 | } |
186 | |
187 | int SDL_SemPost(SDL_sem *sem) |
188 | { |
189 | int retval; |
190 | |
191 | if ( ! sem ) { |
192 | SDL_SetError("Passed a NULL semaphore"); |
193 | return -1; |
194 | } |
195 | |
196 | retval = sem_post(sem->sem); |
197 | if ( retval < 0 ) { |
198 | SDL_SetError("sem_post() failed"); |
199 | } |
200 | return retval; |
201 | } |
202 | |
203 | #endif /* !SDL_THREADS_DISABLED */ |