| 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 | #include "SDL_config.h" |
| 23 | |
| 24 | /* Semaphores in the BeOS environment */ |
| 25 | |
| 26 | #include <be/kernel/OS.h> |
| 27 | |
| 28 | #include "SDL_thread.h" |
| 29 | |
| 30 | |
| 31 | struct SDL_semaphore { |
| 32 | sem_id id; |
| 33 | }; |
| 34 | |
| 35 | /* Create a counting semaphore */ |
| 36 | SDL_sem *SDL_CreateSemaphore(Uint32 initial_value) |
| 37 | { |
| 38 | SDL_sem *sem; |
| 39 | |
| 40 | sem = (SDL_sem *)SDL_malloc(sizeof(*sem)); |
| 41 | if ( sem ) { |
| 42 | sem->id = create_sem(initial_value, "SDL semaphore"); |
| 43 | if ( sem->id < B_NO_ERROR ) { |
| 44 | SDL_SetError("create_sem() failed"); |
| 45 | SDL_free(sem); |
| 46 | sem = NULL; |
| 47 | } |
| 48 | } else { |
| 49 | SDL_OutOfMemory(); |
| 50 | } |
| 51 | return(sem); |
| 52 | } |
| 53 | |
| 54 | /* Free the semaphore */ |
| 55 | void SDL_DestroySemaphore(SDL_sem *sem) |
| 56 | { |
| 57 | if ( sem ) { |
| 58 | if ( sem->id >= B_NO_ERROR ) { |
| 59 | delete_sem(sem->id); |
| 60 | } |
| 61 | SDL_free(sem); |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout) |
| 66 | { |
| 67 | int32 val; |
| 68 | int retval; |
| 69 | |
| 70 | if ( ! sem ) { |
| 71 | SDL_SetError("Passed a NULL semaphore"); |
| 72 | return -1; |
| 73 | } |
| 74 | |
| 75 | tryagain: |
| 76 | if ( timeout == SDL_MUTEX_MAXWAIT ) { |
| 77 | val = acquire_sem(sem->id); |
| 78 | } else { |
| 79 | timeout *= 1000; /* BeOS uses a timeout in microseconds */ |
| 80 | val = acquire_sem_etc(sem->id, 1, B_RELATIVE_TIMEOUT, timeout); |
| 81 | } |
| 82 | switch (val) { |
| 83 | case B_INTERRUPTED: |
| 84 | goto tryagain; |
| 85 | case B_NO_ERROR: |
| 86 | retval = 0; |
| 87 | break; |
| 88 | case B_TIMED_OUT: |
| 89 | retval = SDL_MUTEX_TIMEDOUT; |
| 90 | break; |
| 91 | case B_WOULD_BLOCK: |
| 92 | retval = SDL_MUTEX_TIMEDOUT; |
| 93 | break; |
| 94 | default: |
| 95 | SDL_SetError("acquire_sem() failed"); |
| 96 | retval = -1; |
| 97 | break; |
| 98 | } |
| 99 | |
| 100 | return retval; |
| 101 | } |
| 102 | |
| 103 | int SDL_SemTryWait(SDL_sem *sem) |
| 104 | { |
| 105 | return SDL_SemWaitTimeout(sem, 0); |
| 106 | } |
| 107 | |
| 108 | int SDL_SemWait(SDL_sem *sem) |
| 109 | { |
| 110 | return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT); |
| 111 | } |
| 112 | |
| 113 | /* Returns the current count of the semaphore */ |
| 114 | Uint32 SDL_SemValue(SDL_sem *sem) |
| 115 | { |
| 116 | int32 count; |
| 117 | Uint32 value; |
| 118 | |
| 119 | value = 0; |
| 120 | if ( sem ) { |
| 121 | get_sem_count(sem->id, &count); |
| 122 | if ( count > 0 ) { |
| 123 | value = (Uint32)count; |
| 124 | } |
| 125 | } |
| 126 | return value; |
| 127 | } |
| 128 | |
| 129 | /* Atomically increases the semaphore's count (not blocking) */ |
| 130 | int SDL_SemPost(SDL_sem *sem) |
| 131 | { |
| 132 | if ( ! sem ) { |
| 133 | SDL_SetError("Passed a NULL semaphore"); |
| 134 | return -1; |
| 135 | } |
| 136 | |
| 137 | if ( release_sem(sem->id) != B_NO_ERROR ) { |
| 138 | SDL_SetError("release_sem() failed"); |
| 139 | return -1; |
| 140 | } |
| 141 | return 0; |
| 142 | } |