Mercurial > sdl-ios-xcode
annotate src/thread/generic/SDL_syssem.c @ 1330:450721ad5436
It's now possible to build SDL without any C runtime at all on Windows,
using Visual C++ 2005
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Mon, 06 Feb 2006 08:28:51 +0000 |
| parents | c9b51268668f |
| children | 3692456e7b0f |
| 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 "SDL_error.h" | |
| 26 #include "SDL_timer.h" | |
| 27 #include "SDL_thread.h" | |
|
1330
450721ad5436
It's now possible to build SDL without any C runtime at all on Windows,
Sam Lantinga <slouken@libsdl.org>
parents:
1312
diff
changeset
|
28 #include "SDL_stdlib.h" |
| 0 | 29 #include "SDL_systhread_c.h" |
| 30 | |
| 31 | |
| 32 #ifdef DISABLE_THREADS | |
| 33 | |
| 34 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 35 { | |
| 36 SDL_SetError("SDL not configured with thread support"); | |
| 37 return (SDL_sem *)0; | |
| 38 } | |
| 39 | |
| 40 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 41 { | |
| 42 return; | |
| 43 } | |
| 44 | |
| 45 int SDL_SemTryWait(SDL_sem *sem) | |
| 46 { | |
| 47 SDL_SetError("SDL not configured with thread support"); | |
| 48 return -1; | |
| 49 } | |
| 50 | |
| 51 int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) | |
| 52 { | |
| 53 SDL_SetError("SDL not configured with thread support"); | |
| 54 return -1; | |
| 55 } | |
| 56 | |
| 57 int SDL_SemWait(SDL_sem *sem) | |
| 58 { | |
| 59 SDL_SetError("SDL not configured with thread support"); | |
| 60 return -1; | |
| 61 } | |
| 62 | |
| 63 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 64 { | |
| 65 return 0; | |
| 66 } | |
| 67 | |
| 68 int SDL_SemPost(SDL_sem *sem) | |
| 69 { | |
| 70 SDL_SetError("SDL not configured with thread support"); | |
| 71 return -1; | |
| 72 } | |
| 73 | |
| 74 #else | |
| 75 | |
| 76 struct SDL_semaphore | |
| 77 { | |
| 78 Uint32 count; | |
| 79 Uint32 waiters_count; | |
| 80 SDL_mutex *count_lock; | |
| 81 SDL_cond *count_nonzero; | |
| 82 }; | |
| 83 | |
| 84 SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) | |
| 85 { | |
| 86 SDL_sem *sem; | |
| 87 | |
| 88 sem = (SDL_sem *)malloc(sizeof(*sem)); | |
| 89 if ( ! sem ) { | |
| 90 SDL_OutOfMemory(); | |
| 91 return(0); | |
| 92 } | |
| 93 sem->count = initial_value; | |
| 94 sem->waiters_count = 0; | |
| 95 | |
| 96 sem->count_lock = SDL_CreateMutex(); | |
| 97 sem->count_nonzero = SDL_CreateCond(); | |
| 98 if ( ! sem->count_lock || ! sem->count_nonzero ) { | |
| 99 SDL_DestroySemaphore(sem); | |
| 100 return(0); | |
| 101 } | |
| 102 | |
| 103 return(sem); | |
| 104 } | |
| 105 | |
| 106 /* WARNING: | |
| 107 You cannot call this function when another thread is using the semaphore. | |
| 108 */ | |
| 109 void SDL_DestroySemaphore(SDL_sem *sem) | |
| 110 { | |
| 111 if ( sem ) { | |
| 112 sem->count = 0xFFFFFFFF; | |
| 113 while ( sem->waiters_count > 0) { | |
| 114 SDL_CondSignal(sem->count_nonzero); | |
| 115 SDL_Delay(10); | |
| 116 } | |
| 117 SDL_DestroyCond(sem->count_nonzero); | |
| 118 SDL_mutexP(sem->count_lock); | |
| 119 SDL_mutexV(sem->count_lock); | |
| 120 SDL_DestroyMutex(sem->count_lock); | |
| 121 free(sem); | |
| 122 } | |
| 123 } | |
| 124 | |
| 125 int SDL_SemTryWait(SDL_sem *sem) | |
| 126 { | |
| 127 int retval; | |
| 128 | |
| 129 if ( ! sem ) { | |
| 130 SDL_SetError("Passed a NULL semaphore"); | |
| 131 return -1; | |
| 132 } | |
| 133 | |
| 134 retval = SDL_MUTEX_TIMEDOUT; | |
| 135 SDL_LockMutex(sem->count_lock); | |
| 136 if ( sem->count > 0 ) { | |
| 137 --sem->count; | |
| 138 retval = 0; | |
| 139 } | |
| 140 SDL_UnlockMutex(sem->count_lock); | |
| 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 /* A timeout of 0 is an easy case */ | |
| 155 if ( timeout == 0 ) { | |
| 156 return SDL_SemTryWait(sem); | |
| 157 } | |
| 158 | |
| 159 SDL_LockMutex(sem->count_lock); | |
| 160 ++sem->waiters_count; | |
| 161 retval = 0; | |
| 162 while ( (sem->count == 0) && (retval != SDL_MUTEX_TIMEDOUT) ) { | |
| 163 retval = SDL_CondWaitTimeout(sem->count_nonzero, | |
| 164 sem->count_lock, timeout); | |
| 165 } | |
| 166 --sem->waiters_count; | |
| 167 --sem->count; | |
| 168 SDL_UnlockMutex(sem->count_lock); | |
| 169 | |
| 170 return retval; | |
| 171 } | |
| 172 | |
| 173 int SDL_SemWait(SDL_sem *sem) | |
| 174 { | |
| 175 return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); | |
| 176 } | |
| 177 | |
| 178 Uint32 SDL_SemValue(SDL_sem *sem) | |
| 179 { | |
| 180 Uint32 value; | |
| 181 | |
| 182 value = 0; | |
| 183 if ( sem ) { | |
| 184 SDL_LockMutex(sem->count_lock); | |
| 185 value = sem->count; | |
| 186 SDL_UnlockMutex(sem->count_lock); | |
| 187 } | |
| 188 return value; | |
| 189 } | |
| 190 | |
| 191 int SDL_SemPost(SDL_sem *sem) | |
| 192 { | |
| 193 if ( ! sem ) { | |
| 194 SDL_SetError("Passed a NULL semaphore"); | |
| 195 return -1; | |
| 196 } | |
| 197 | |
| 198 SDL_LockMutex(sem->count_lock); | |
| 199 if ( sem->waiters_count > 0 ) { | |
| 200 SDL_CondSignal(sem->count_nonzero); | |
| 201 } | |
| 202 ++sem->count; | |
| 203 SDL_UnlockMutex(sem->count_lock); | |
| 204 | |
| 205 return 0; | |
| 206 } | |
| 207 | |
| 208 #endif /* DISABLE_THREADS */ |