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 | /* An implementation of semaphores using mutexes and condition variables */ |
28 | |
29 | #include "SDL_timer.h" |
30 | #include "SDL_thread.h" |
31 | #include "SDL_systhread_c.h" |
32 | |
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 | #include <kos/sem.h> |
79 | |
80 | struct SDL_semaphore |
81 | { |
82 | semaphore_t sem; |
83 | }; |
84 | |
85 | SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) |
86 | { |
87 | return (SDL_sem *)sem_create(initial_value); |
88 | } |
89 | |
90 | /* WARNING: |
91 | You cannot call this function when another thread is using the semaphore. |
92 | */ |
93 | void SDL_DestroySemaphore(SDL_sem *sem) |
94 | { |
95 | if ( ! sem ) { |
96 | SDL_SetError("Passed a NULL semaphore"); |
97 | return; |
98 | } |
99 | |
100 | sem_destroy(&sem->sem); |
101 | } |
102 | |
103 | int SDL_SemTryWait(SDL_sem *sem) |
104 | { |
105 | int retval; |
106 | |
107 | if ( ! sem ) { |
108 | SDL_SetError("Passed a NULL semaphore"); |
109 | return -1; |
110 | } |
111 | |
112 | retval = sem_trywait(&sem->sem); |
113 | if (retval==0) return 0; |
114 | else return SDL_MUTEX_TIMEDOUT; |
115 | |
116 | return retval; |
117 | } |
118 | |
119 | int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) |
120 | { |
121 | int retval; |
122 | |
123 | if ( ! sem ) { |
124 | SDL_SetError("Passed a NULL semaphore"); |
125 | return -1; |
126 | } |
127 | |
128 | /* A timeout of 0 is an easy case */ |
129 | if ( timeout == 0 ) { |
130 | return SDL_SemTryWait(sem); |
131 | } |
132 | |
133 | retval = sem_wait_timed(&sem->sem,timeout); |
134 | if (retval==-1) retval= SDL_MUTEX_TIMEDOUT; |
135 | |
136 | return retval; |
137 | } |
138 | |
139 | int SDL_SemWait(SDL_sem *sem) |
140 | { |
141 | int retval; |
142 | |
143 | if ( ! sem ) { |
144 | SDL_SetError("Passed a NULL semaphore"); |
145 | return -1; |
146 | } |
147 | |
148 | while ( ((retval = sem_wait(&sem->sem)) == -1) && (errno == EINTR) ) {} |
149 | return retval; |
150 | } |
151 | |
152 | Uint32 SDL_SemValue(SDL_sem *sem) |
153 | { |
154 | if ( ! sem ) { |
155 | SDL_SetError("Passed a NULL semaphore"); |
156 | return -1; |
157 | } |
158 | |
159 | return sem_count(&sem->sem); |
160 | } |
161 | |
162 | int SDL_SemPost(SDL_sem *sem) |
163 | { |
164 | if ( ! sem ) { |
165 | SDL_SetError("Passed a NULL semaphore"); |
166 | return -1; |
167 | } |
168 | |
169 | sem_signal(&sem->sem); |
170 | return 0; |
171 | } |
172 | |
173 | #endif /* SDL_THREADS_DISABLED */ |