| 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 */ |