diff options
Diffstat (limited to 'apps/plugins/sdl/src/thread/dc/SDL_syscond.c')
-rw-r--r-- | apps/plugins/sdl/src/thread/dc/SDL_syscond.c | 215 |
1 files changed, 0 insertions, 215 deletions
diff --git a/apps/plugins/sdl/src/thread/dc/SDL_syscond.c b/apps/plugins/sdl/src/thread/dc/SDL_syscond.c deleted file mode 100644 index f6e7223e3d..0000000000 --- a/apps/plugins/sdl/src/thread/dc/SDL_syscond.c +++ /dev/null | |||
@@ -1,215 +0,0 @@ | |||
1 | /* | ||
2 | SDL - Simple DirectMedia Layer | ||
3 | Copyright (C) 1997-2012 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 | #include "SDL_config.h" | ||
23 | |||
24 | /* An implementation of condition variables using semaphores and mutexes */ | ||
25 | /* | ||
26 | This implementation borrows heavily from the BeOS condition variable | ||
27 | implementation, written by Christopher Tate and Owen Smith. Thanks! | ||
28 | */ | ||
29 | |||
30 | #include "SDL_thread.h" | ||
31 | |||
32 | struct SDL_cond | ||
33 | { | ||
34 | SDL_mutex *lock; | ||
35 | int waiting; | ||
36 | int signals; | ||
37 | SDL_sem *wait_sem; | ||
38 | SDL_sem *wait_done; | ||
39 | }; | ||
40 | |||
41 | /* Create a condition variable */ | ||
42 | SDL_cond * SDL_CreateCond(void) | ||
43 | { | ||
44 | SDL_cond *cond; | ||
45 | |||
46 | cond = (SDL_cond *) SDL_malloc(sizeof(SDL_cond)); | ||
47 | if ( cond ) { | ||
48 | cond->lock = SDL_CreateMutex(); | ||
49 | cond->wait_sem = SDL_CreateSemaphore(0); | ||
50 | cond->wait_done = SDL_CreateSemaphore(0); | ||
51 | cond->waiting = cond->signals = 0; | ||
52 | if ( ! cond->lock || ! cond->wait_sem || ! cond->wait_done ) { | ||
53 | SDL_DestroyCond(cond); | ||
54 | cond = NULL; | ||
55 | } | ||
56 | } else { | ||
57 | SDL_OutOfMemory(); | ||
58 | } | ||
59 | return(cond); | ||
60 | } | ||
61 | |||
62 | /* Destroy a condition variable */ | ||
63 | void SDL_DestroyCond(SDL_cond *cond) | ||
64 | { | ||
65 | if ( cond ) { | ||
66 | if ( cond->wait_sem ) { | ||
67 | SDL_DestroySemaphore(cond->wait_sem); | ||
68 | } | ||
69 | if ( cond->wait_done ) { | ||
70 | SDL_DestroySemaphore(cond->wait_done); | ||
71 | } | ||
72 | if ( cond->lock ) { | ||
73 | SDL_DestroyMutex(cond->lock); | ||
74 | } | ||
75 | SDL_free(cond); | ||
76 | } | ||
77 | } | ||
78 | |||
79 | /* Restart one of the threads that are waiting on the condition variable */ | ||
80 | int SDL_CondSignal(SDL_cond *cond) | ||
81 | { | ||
82 | if ( ! cond ) { | ||
83 | SDL_SetError("Passed a NULL condition variable"); | ||
84 | return -1; | ||
85 | } | ||
86 | |||
87 | /* If there are waiting threads not already signalled, then | ||
88 | signal the condition and wait for the thread to respond. | ||
89 | */ | ||
90 | SDL_LockMutex(cond->lock); | ||
91 | if ( cond->waiting > cond->signals ) { | ||
92 | ++cond->signals; | ||
93 | SDL_SemPost(cond->wait_sem); | ||
94 | SDL_UnlockMutex(cond->lock); | ||
95 | SDL_SemWait(cond->wait_done); | ||
96 | } else { | ||
97 | SDL_UnlockMutex(cond->lock); | ||
98 | } | ||
99 | |||
100 | return 0; | ||
101 | } | ||
102 | |||
103 | /* Restart all threads that are waiting on the condition variable */ | ||
104 | int SDL_CondBroadcast(SDL_cond *cond) | ||
105 | { | ||
106 | if ( ! cond ) { | ||
107 | SDL_SetError("Passed a NULL condition variable"); | ||
108 | return -1; | ||
109 | } | ||
110 | |||
111 | /* If there are waiting threads not already signalled, then | ||
112 | signal the condition and wait for the thread to respond. | ||
113 | */ | ||
114 | SDL_LockMutex(cond->lock); | ||
115 | if ( cond->waiting > cond->signals ) { | ||
116 | int i, num_waiting; | ||
117 | |||
118 | num_waiting = (cond->waiting - cond->signals); | ||
119 | cond->signals = cond->waiting; | ||
120 | for ( i=0; i<num_waiting; ++i ) { | ||
121 | SDL_SemPost(cond->wait_sem); | ||
122 | } | ||
123 | /* Now all released threads are blocked here, waiting for us. | ||
124 | Collect them all (and win fabulous prizes!) :-) | ||
125 | */ | ||
126 | SDL_UnlockMutex(cond->lock); | ||
127 | for ( i=0; i<num_waiting; ++i ) { | ||
128 | SDL_SemWait(cond->wait_done); | ||
129 | } | ||
130 | } else { | ||
131 | SDL_UnlockMutex(cond->lock); | ||
132 | } | ||
133 | |||
134 | return 0; | ||
135 | } | ||
136 | |||
137 | /* Wait on the condition variable for at most 'ms' milliseconds. | ||
138 | The mutex must be locked before entering this function! | ||
139 | The mutex is unlocked during the wait, and locked again after the wait. | ||
140 | |||
141 | Typical use: | ||
142 | |||
143 | Thread A: | ||
144 | SDL_LockMutex(lock); | ||
145 | while ( ! condition ) { | ||
146 | SDL_CondWait(cond); | ||
147 | } | ||
148 | SDL_UnlockMutex(lock); | ||
149 | |||
150 | Thread B: | ||
151 | SDL_LockMutex(lock); | ||
152 | ... | ||
153 | condition = true; | ||
154 | ... | ||
155 | SDL_UnlockMutex(lock); | ||
156 | */ | ||
157 | int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms) | ||
158 | { | ||
159 | int retval; | ||
160 | |||
161 | if ( ! cond ) { | ||
162 | SDL_SetError("Passed a NULL condition variable"); | ||
163 | return -1; | ||
164 | } | ||
165 | |||
166 | /* Obtain the protection mutex, and increment the number of waiters. | ||
167 | This allows the signal mechanism to only perform a signal if there | ||
168 | are waiting threads. | ||
169 | */ | ||
170 | SDL_LockMutex(cond->lock); | ||
171 | ++cond->waiting; | ||
172 | SDL_UnlockMutex(cond->lock); | ||
173 | |||
174 | /* Unlock the mutex, as is required by condition variable semantics */ | ||
175 | SDL_UnlockMutex(mutex); | ||
176 | |||
177 | /* Wait for a signal */ | ||
178 | if ( ms == SDL_MUTEX_MAXWAIT ) { | ||
179 | retval = SDL_SemWait(cond->wait_sem); | ||
180 | } else { | ||
181 | retval = SDL_SemWaitTimeout(cond->wait_sem, ms); | ||
182 | } | ||
183 | |||
184 | /* Let the signaler know we have completed the wait, otherwise | ||
185 | the signaler can race ahead and get the condition semaphore | ||
186 | if we are stopped between the mutex unlock and semaphore wait, | ||
187 | giving a deadlock. See the following URL for details: | ||
188 | http://www-classic.be.com/aboutbe/benewsletter/volume_III/Issue40.html | ||
189 | */ | ||
190 | SDL_LockMutex(cond->lock); | ||
191 | if ( cond->signals > 0 ) { | ||
192 | /* If we timed out, we need to eat a condition signal */ | ||
193 | if ( retval > 0 ) { | ||
194 | SDL_SemWait(cond->wait_sem); | ||
195 | } | ||
196 | /* We always notify the signal thread that we are done */ | ||
197 | SDL_SemPost(cond->wait_done); | ||
198 | |||
199 | /* Signal handshake complete */ | ||
200 | --cond->signals; | ||
201 | } | ||
202 | --cond->waiting; | ||
203 | SDL_UnlockMutex(cond->lock); | ||
204 | |||
205 | /* Lock the mutex, as is required by condition variable semantics */ | ||
206 | SDL_LockMutex(mutex); | ||
207 | |||
208 | return retval; | ||
209 | } | ||
210 | |||
211 | /* Wait on the condition variable forever */ | ||
212 | int SDL_CondWait(SDL_cond *cond, SDL_mutex *mutex) | ||
213 | { | ||
214 | return SDL_CondWaitTimeout(cond, mutex, SDL_MUTEX_MAXWAIT); | ||
215 | } | ||