Mercurial > sdl-ios-xcode
annotate src/thread/generic/SDL_syssem.c @ 4301:5007e6a66814 SDL-1.2
Debian patch: 209_alsa_priority.diff
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sat, 10 Oct 2009 09:07:51 +0000 |
| parents | 62e86ab81e3c |
| children |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
| 4159 | 3 Copyright (C) 1997-2009 Sam Lantinga |
| 0 | 4 |
| 5 This library is free software; you can redistribute it and/or | |
|
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6 modify it under the terms of the GNU Lesser General Public |
| 0 | 7 License as published by the Free Software Foundation; either |
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8 version 2.1 of the License, or (at your option) any later version. |
| 0 | 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 | |
|
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13 Lesser General Public License for more details. |
| 0 | 14 |
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15 You should have received a copy of the GNU Lesser General Public |
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c9b51268668f
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Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
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16 License along with this library; if not, write to the Free Software |
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Sam Lantinga <slouken@libsdl.org>
parents:
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diff
changeset
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17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 0 | 18 |
| 19 Sam Lantinga | |
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20 slouken@libsdl.org |
| 0 | 21 */ |
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22 #include "SDL_config.h" |
| 0 | 23 |
| 24 /* An implementation of semaphores using mutexes and condition variables */ | |
| 25 | |
| 26 #include "SDL_timer.h" | |
| 27 #include "SDL_thread.h" | |
| 28 #include "SDL_systhread_c.h" | |
| 29 | |
| 30 | |
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31 #if SDL_THREADS_DISABLED |
| 0 | 32 |
| 33 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 34 { | |
| 35 SDL_SetError("SDL not configured with thread support"); | |
| 36 return (SDL_sem *)0; | |
| 37 } | |
| 38 | |
| 39 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 40 { | |
| 41 return; | |
| 42 } | |
| 43 | |
| 44 int SDL_SemTryWait(SDL_sem *sem) | |
| 45 { | |
| 46 SDL_SetError("SDL not configured with thread support"); | |
| 47 return -1; | |
| 48 } | |
| 49 | |
| 50 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
| 51 { | |
| 52 SDL_SetError("SDL not configured with thread support"); | |
| 53 return -1; | |
| 54 } | |
| 55 | |
| 56 int SDL_SemWait(SDL_sem *sem) | |
| 57 { | |
| 58 SDL_SetError("SDL not configured with thread support"); | |
| 59 return -1; | |
| 60 } | |
| 61 | |
| 62 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 63 { | |
| 64 return 0; | |
| 65 } | |
| 66 | |
| 67 int SDL_SemPost(SDL_sem *sem) | |
| 68 { | |
| 69 SDL_SetError("SDL not configured with thread support"); | |
| 70 return -1; | |
| 71 } | |
| 72 | |
| 73 #else | |
| 74 | |
| 75 struct SDL_semaphore | |
| 76 { | |
| 77 Uint32 count; | |
| 78 Uint32 waiters_count; | |
| 79 SDL_mutex *count_lock; | |
| 80 SDL_cond *count_nonzero; | |
| 81 }; | |
| 82 | |
| 83 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 84 { | |
| 85 SDL_sem *sem; | |
| 86 | |
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87 sem = (SDL_sem *)SDL_malloc(sizeof(*sem)); |
| 0 | 88 if ( ! sem ) { |
| 89 SDL_OutOfMemory(); | |
| 1627 | 90 return NULL; |
| 0 | 91 } |
| 92 sem->count = initial_value; | |
| 93 sem->waiters_count = 0; | |
| 94 | |
| 95 sem->count_lock = SDL_CreateMutex(); | |
| 96 sem->count_nonzero = SDL_CreateCond(); | |
| 97 if ( ! sem->count_lock || ! sem->count_nonzero ) { | |
| 98 SDL_DestroySemaphore(sem); | |
| 1627 | 99 return NULL; |
| 0 | 100 } |
| 101 | |
| 1627 | 102 return sem; |
| 0 | 103 } |
| 104 | |
| 105 /* WARNING: | |
| 106 You cannot call this function when another thread is using the semaphore. | |
| 107 */ | |
| 108 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 109 { | |
| 110 if ( sem ) { | |
| 111 sem->count = 0xFFFFFFFF; | |
| 112 while ( sem->waiters_count > 0) { | |
| 113 SDL_CondSignal(sem->count_nonzero); | |
| 114 SDL_Delay(10); | |
| 115 } | |
| 116 SDL_DestroyCond(sem->count_nonzero); | |
| 1627 | 117 if ( sem->count_lock ) { |
| 118 SDL_mutexP(sem->count_lock); | |
| 119 SDL_mutexV(sem->count_lock); | |
| 120 SDL_DestroyMutex(sem->count_lock); | |
| 121 } | |
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parents:
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diff
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122 SDL_free(sem); |
| 0 | 123 } |
| 124 } | |
| 125 | |
| 126 int SDL_SemTryWait(SDL_sem *sem) | |
| 127 { | |
| 128 int retval; | |
| 129 | |
| 130 if ( ! sem ) { | |
| 131 SDL_SetError("Passed a NULL semaphore"); | |
| 132 return -1; | |
| 133 } | |
| 134 | |
| 135 retval = SDL_MUTEX_TIMEDOUT; | |
| 136 SDL_LockMutex(sem->count_lock); | |
| 137 if ( sem->count > 0 ) { | |
| 138 --sem->count; | |
| 139 retval = 0; | |
| 140 } | |
| 141 SDL_UnlockMutex(sem->count_lock); | |
| 142 | |
| 143 return retval; | |
| 144 } | |
| 145 | |
| 146 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
| 147 { | |
| 148 int retval; | |
| 149 | |
| 150 if ( ! sem ) { | |
| 151 SDL_SetError("Passed a NULL semaphore"); | |
| 152 return -1; | |
| 153 } | |
| 154 | |
| 155 /* A timeout of 0 is an easy case */ | |
| 156 if ( timeout == 0 ) { | |
| 157 return SDL_SemTryWait(sem); | |
| 158 } | |
| 159 | |
| 160 SDL_LockMutex(sem->count_lock); | |
| 161 ++sem->waiters_count; | |
| 162 retval = 0; | |
| 163 while ( (sem->count == 0) && (retval != SDL_MUTEX_TIMEDOUT) ) { | |
| 164 retval = SDL_CondWaitTimeout(sem->count_nonzero, | |
| 165 sem->count_lock, timeout); | |
| 166 } | |
| 167 --sem->waiters_count; | |
| 4209 | 168 if (retval == 0) { |
| 169 --sem->count; | |
| 170 } | |
| 0 | 171 SDL_UnlockMutex(sem->count_lock); |
| 172 | |
| 173 return retval; | |
| 174 } | |
| 175 | |
| 176 int SDL_SemWait(SDL_sem *sem) | |
| 177 { | |
| 178 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); | |
| 179 } | |
| 180 | |
| 181 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 182 { | |
| 183 Uint32 value; | |
| 184 | |
| 185 value = 0; | |
| 186 if ( sem ) { | |
| 187 SDL_LockMutex(sem->count_lock); | |
| 188 value = sem->count; | |
| 189 SDL_UnlockMutex(sem->count_lock); | |
| 190 } | |
| 191 return value; | |
| 192 } | |
| 193 | |
| 194 int SDL_SemPost(SDL_sem *sem) | |
| 195 { | |
| 196 if ( ! sem ) { | |
| 197 SDL_SetError("Passed a NULL semaphore"); | |
| 198 return -1; | |
| 199 } | |
| 200 | |
| 201 SDL_LockMutex(sem->count_lock); | |
| 202 if ( sem->waiters_count > 0 ) { | |
| 203 SDL_CondSignal(sem->count_nonzero); | |
| 204 } | |
| 205 ++sem->count; | |
| 206 SDL_UnlockMutex(sem->count_lock); | |
| 207 | |
| 208 return 0; | |
| 209 } | |
| 210 | |
|
1361
19418e4422cb
New configure-based build system. Still work in progress, but much improved
Sam Lantinga <slouken@libsdl.org>
parents:
1358
diff
changeset
|
211 #endif /* SDL_THREADS_DISABLED */ |