| 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 | /* RISC OS semiphores based on linux code */ |
| 28 | |
| 29 | |
| 30 | #include "SDL_timer.h" |
| 31 | #include "SDL_thread.h" |
| 32 | #include "SDL_systhread_c.h" |
| 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 | |
| 79 | #include <unistd.h> /* For getpid() */ |
| 80 | #include <pthread.h> |
| 81 | #include <semaphore.h> |
| 82 | |
| 83 | struct SDL_semaphore { |
| 84 | sem_t *sem; |
| 85 | sem_t sem_data; |
| 86 | }; |
| 87 | |
| 88 | /* Create a semaphore, initialized with value */ |
| 89 | SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) |
| 90 | { |
| 91 | SDL_sem *sem = (SDL_sem *) SDL_malloc(sizeof(SDL_sem)); |
| 92 | if ( sem ) { |
| 93 | if ( sem_init(&sem->sem_data, 0, initial_value) < 0 ) { |
| 94 | SDL_SetError("sem_init() failed"); |
| 95 | SDL_free(sem); |
| 96 | sem = NULL; |
| 97 | } else { |
| 98 | sem->sem = &sem->sem_data; |
| 99 | } |
| 100 | } else { |
| 101 | SDL_OutOfMemory(); |
| 102 | } |
| 103 | return sem; |
| 104 | } |
| 105 | |
| 106 | void SDL_DestroySemaphore(SDL_sem *sem) |
| 107 | { |
| 108 | if ( sem ) { |
| 109 | sem_destroy(sem->sem); |
| 110 | SDL_free(sem); |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | int SDL_SemTryWait(SDL_sem *sem) |
| 115 | { |
| 116 | int retval; |
| 117 | |
| 118 | if ( ! sem ) { |
| 119 | SDL_SetError("Passed a NULL semaphore"); |
| 120 | return -1; |
| 121 | } |
| 122 | retval = SDL_MUTEX_TIMEDOUT; |
| 123 | if ( sem_trywait(sem->sem) == 0 ) { |
| 124 | retval = 0; |
| 125 | } |
| 126 | return retval; |
| 127 | } |
| 128 | |
| 129 | int SDL_SemWait(SDL_sem *sem) |
| 130 | { |
| 131 | int retval; |
| 132 | |
| 133 | if ( ! sem ) { |
| 134 | SDL_SetError("Passed a NULL semaphore"); |
| 135 | return -1; |
| 136 | } |
| 137 | |
| 138 | while ( ((retval = sem_wait(sem->sem)) == -1) && (errno == EINTR) ) {} |
| 139 | if ( retval < 0 ) { |
| 140 | SDL_SetError("sem_wait() failed"); |
| 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 | /* Try the easy cases first */ |
| 155 | if ( timeout == 0 ) { |
| 156 | return SDL_SemTryWait(sem); |
| 157 | } |
| 158 | if ( timeout == SDL_MUTEX_MAXWAIT ) { |
| 159 | return SDL_SemWait(sem); |
| 160 | } |
| 161 | |
| 162 | /* Ack! We have to busy wait... */ |
| 163 | timeout += SDL_GetTicks(); |
| 164 | do { |
| 165 | retval = SDL_SemTryWait(sem); |
| 166 | if ( retval == 0 ) { |
| 167 | break; |
| 168 | } |
| 169 | SDL_Delay(1); |
| 170 | } while ( SDL_GetTicks() < timeout ); |
| 171 | |
| 172 | return retval; |
| 173 | } |
| 174 | |
| 175 | Uint32 SDL_SemValue(SDL_sem *sem) |
| 176 | { |
| 177 | int ret = 0; |
| 178 | if ( sem ) { |
| 179 | sem_getvalue(sem->sem, &ret); |
| 180 | if ( ret < 0 ) { |
| 181 | ret = 0; |
| 182 | } |
| 183 | } |
| 184 | return (Uint32)ret; |
| 185 | } |
| 186 | |
| 187 | int SDL_SemPost(SDL_sem *sem) |
| 188 | { |
| 189 | int retval; |
| 190 | |
| 191 | if ( ! sem ) { |
| 192 | SDL_SetError("Passed a NULL semaphore"); |
| 193 | return -1; |
| 194 | } |
| 195 | |
| 196 | retval = sem_post(sem->sem); |
| 197 | if ( retval < 0 ) { |
| 198 | SDL_SetError("sem_post() failed"); |
| 199 | } |
| 200 | return retval; |
| 201 | } |
| 202 | |
| 203 | #endif /* !SDL_THREADS_DISABLED */ |