Mercurial > sdl-ios-xcode
annotate src/thread/generic/SDL_syssem.c @ 1312:c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
I batch edited these files, so please let me know if I've accidentally removed anybody's
credit here.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Wed, 01 Feb 2006 06:32:25 +0000 |
| parents | b8d311d90021 |
| children | 450721ad5436 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
|
1312
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
|
3 Copyright (C) 1997-2006 Sam Lantinga |
| 0 | 4 |
| 5 This library is free software; you can redistribute it and/or | |
|
1312
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
|
6 modify it under the terms of the GNU Lesser General Public |
| 0 | 7 License as published by the Free Software Foundation; either |
|
1312
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
|
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 | |
|
1312
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
|
13 Lesser General Public License for more details. |
| 0 | 14 |
|
1312
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
|
15 You should have received a copy of the GNU Lesser General Public |
|
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
|
16 License along with this library; if not, write to the Free Software |
|
c9b51268668f
Updated copyright information and removed rcs id lines (problematic in branch merges)
Sam Lantinga <slouken@libsdl.org>
parents:
769
diff
changeset
|
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 0 | 18 |
| 19 Sam Lantinga | |
|
252
e8157fcb3114
Updated the source with the correct e-mail address
Sam Lantinga <slouken@libsdl.org>
parents:
0
diff
changeset
|
20 slouken@libsdl.org |
| 0 | 21 */ |
| 22 | |
| 23 /* An implementation of semaphores using mutexes and condition variables */ | |
| 24 | |
| 25 #include <stdlib.h> | |
| 26 | |
| 27 #include "SDL_error.h" | |
| 28 #include "SDL_timer.h" | |
| 29 #include "SDL_thread.h" | |
| 30 #include "SDL_systhread_c.h" | |
| 31 | |
| 32 | |
| 33 #ifdef DISABLE_THREADS | |
| 34 | |
| 35 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 36 { | |
| 37 SDL_SetError("SDL not configured with thread support"); | |
| 38 return (SDL_sem *)0; | |
| 39 } | |
| 40 | |
| 41 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 42 { | |
| 43 return; | |
| 44 } | |
| 45 | |
| 46 int SDL_SemTryWait(SDL_sem *sem) | |
| 47 { | |
| 48 SDL_SetError("SDL not configured with thread support"); | |
| 49 return -1; | |
| 50 } | |
| 51 | |
| 52 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
| 53 { | |
| 54 SDL_SetError("SDL not configured with thread support"); | |
| 55 return -1; | |
| 56 } | |
| 57 | |
| 58 int SDL_SemWait(SDL_sem *sem) | |
| 59 { | |
| 60 SDL_SetError("SDL not configured with thread support"); | |
| 61 return -1; | |
| 62 } | |
| 63 | |
| 64 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 65 { | |
| 66 return 0; | |
| 67 } | |
| 68 | |
| 69 int SDL_SemPost(SDL_sem *sem) | |
| 70 { | |
| 71 SDL_SetError("SDL not configured with thread support"); | |
| 72 return -1; | |
| 73 } | |
| 74 | |
| 75 #else | |
| 76 | |
| 77 struct SDL_semaphore | |
| 78 { | |
| 79 Uint32 count; | |
| 80 Uint32 waiters_count; | |
| 81 SDL_mutex *count_lock; | |
| 82 SDL_cond *count_nonzero; | |
| 83 }; | |
| 84 | |
| 85 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 86 { | |
| 87 SDL_sem *sem; | |
| 88 | |
| 89 sem = (SDL_sem *)malloc(sizeof(*sem)); | |
| 90 if ( ! sem ) { | |
| 91 SDL_OutOfMemory(); | |
| 92 return(0); | |
| 93 } | |
| 94 sem->count = initial_value; | |
| 95 sem->waiters_count = 0; | |
| 96 | |
| 97 sem->count_lock = SDL_CreateMutex(); | |
| 98 sem->count_nonzero = SDL_CreateCond(); | |
| 99 if ( ! sem->count_lock || ! sem->count_nonzero ) { | |
| 100 SDL_DestroySemaphore(sem); | |
| 101 return(0); | |
| 102 } | |
| 103 | |
| 104 return(sem); | |
| 105 } | |
| 106 | |
| 107 /* WARNING: | |
| 108 You cannot call this function when another thread is using the semaphore. | |
| 109 */ | |
| 110 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 111 { | |
| 112 if ( sem ) { | |
| 113 sem->count = 0xFFFFFFFF; | |
| 114 while ( sem->waiters_count > 0) { | |
| 115 SDL_CondSignal(sem->count_nonzero); | |
| 116 SDL_Delay(10); | |
| 117 } | |
| 118 SDL_DestroyCond(sem->count_nonzero); | |
| 119 SDL_mutexP(sem->count_lock); | |
| 120 SDL_mutexV(sem->count_lock); | |
| 121 SDL_DestroyMutex(sem->count_lock); | |
| 122 free(sem); | |
| 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; | |
| 168 --sem->count; | |
| 169 SDL_UnlockMutex(sem->count_lock); | |
| 170 | |
| 171 return retval; | |
| 172 } | |
| 173 | |
| 174 int SDL_SemWait(SDL_sem *sem) | |
| 175 { | |
| 176 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); | |
| 177 } | |
| 178 | |
| 179 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 180 { | |
| 181 Uint32 value; | |
| 182 | |
| 183 value = 0; | |
| 184 if ( sem ) { | |
| 185 SDL_LockMutex(sem->count_lock); | |
| 186 value = sem->count; | |
| 187 SDL_UnlockMutex(sem->count_lock); | |
| 188 } | |
| 189 return value; | |
| 190 } | |
| 191 | |
| 192 int SDL_SemPost(SDL_sem *sem) | |
| 193 { | |
| 194 if ( ! sem ) { | |
| 195 SDL_SetError("Passed a NULL semaphore"); | |
| 196 return -1; | |
| 197 } | |
| 198 | |
| 199 SDL_LockMutex(sem->count_lock); | |
| 200 if ( sem->waiters_count > 0 ) { | |
| 201 SDL_CondSignal(sem->count_nonzero); | |
| 202 } | |
| 203 ++sem->count; | |
| 204 SDL_UnlockMutex(sem->count_lock); | |
| 205 | |
| 206 return 0; | |
| 207 } | |
| 208 | |
| 209 #endif /* DISABLE_THREADS */ |