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| Rev | Author | Line No. | Line |
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| 5131 | clevermous | 1 | /* WARNING: This file was automatically generated! |
| 2 | * Original: ./src/thread/generic/SDL_sysmutex.c |
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| 3 | */ |
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| 4 | /* |
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| 5 | SDL - Simple DirectMedia Layer |
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| 6 | Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga |
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| 7 | |||
| 8 | This library is free software; you can redistribute it and/or |
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| 9 | modify it under the terms of the GNU Library General Public |
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| 10 | License as published by the Free Software Foundation; either |
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| 11 | version 2 of the License, or (at your option) any later version. |
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| 12 | |||
| 13 | This library is distributed in the hope that it will be useful, |
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| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 16 | Library General Public License for more details. |
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| 17 | |||
| 18 | You should have received a copy of the GNU Library General Public |
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| 19 | License along with this library; if not, write to the Free |
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| 20 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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| 21 | |||
| 22 | Sam Lantinga |
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| 23 | slouken@devolution.com |
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| 24 | */ |
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| 25 | |||
| 26 | |||
| 27 | /* An implementation of mutexes using semaphores */ |
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| 28 | |||
| 29 | #include |
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| 30 | #include |
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| 31 | |||
| 32 | #include "SDL_error.h" |
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| 33 | #include "SDL_thread.h" |
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| 34 | #include "SDL_systhread_c.h" |
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| 35 | |||
| 36 | |||
| 37 | struct SDL_mutex { |
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| 38 | int recursive; |
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| 39 | Uint32 owner; |
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| 40 | SDL_sem *sem; |
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| 41 | }; |
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| 42 | |||
| 43 | /* Create a mutex */ |
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| 44 | SDL_mutex *SDL_CreateMutex(void) |
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| 45 | { |
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| 46 | SDL_mutex *mutex; |
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| 47 | |||
| 48 | /* Allocate mutex memory */ |
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| 49 | mutex = (SDL_mutex *)malloc(sizeof(*mutex)); |
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| 50 | if ( mutex ) { |
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| 51 | /* Create the mutex semaphore, with initial value 1 */ |
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| 52 | mutex->sem = SDL_CreateSemaphore(1); |
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| 53 | mutex->recursive = 0; |
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| 54 | mutex->owner = 0; |
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| 55 | if ( ! mutex->sem ) { |
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| 56 | free(mutex); |
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| 57 | mutex = NULL; |
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| 58 | } |
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| 59 | } else { |
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| 60 | SDL_OutOfMemory(); |
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| 61 | } |
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| 62 | return mutex; |
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| 63 | } |
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| 64 | |||
| 65 | /* Free the mutex */ |
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| 66 | void SDL_DestroyMutex(SDL_mutex *mutex) |
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| 67 | { |
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| 68 | if ( mutex ) { |
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| 69 | if ( mutex->sem ) { |
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| 70 | SDL_DestroySemaphore(mutex->sem); |
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| 71 | } |
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| 72 | free(mutex); |
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| 73 | } |
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| 74 | } |
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| 75 | |||
| 76 | /* Lock the semaphore */ |
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| 77 | int SDL_mutexP(SDL_mutex *mutex) |
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| 78 | { |
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| 79 | #ifdef DISABLE_THREADS |
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| 80 | return 0; |
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| 81 | #else |
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| 82 | Uint32 this_thread; |
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| 83 | |||
| 84 | if ( mutex == NULL ) { |
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| 85 | SDL_SetError("Passed a NULL mutex"); |
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| 86 | return -1; |
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| 87 | } |
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| 88 | |||
| 89 | this_thread = SDL_ThreadID(); |
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| 90 | if ( mutex->owner == this_thread ) { |
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| 91 | ++mutex->recursive; |
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| 92 | } else { |
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| 93 | /* The order of operations is important. |
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| 94 | We set the locking thread id after we obtain the lock |
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| 95 | so unlocks from other threads will fail. |
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| 96 | */ |
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| 97 | SDL_SemWait(mutex->sem); |
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| 98 | mutex->owner = this_thread; |
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| 99 | mutex->recursive = 0; |
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| 100 | } |
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| 101 | |||
| 102 | return 0; |
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| 103 | #endif /* DISABLE_THREADS */ |
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| 104 | } |
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| 105 | |||
| 106 | /* Unlock the mutex */ |
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| 107 | int SDL_mutexV(SDL_mutex *mutex) |
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| 108 | { |
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| 109 | #ifdef DISABLE_THREADS |
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| 110 | return 0; |
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| 111 | #else |
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| 112 | if ( mutex == NULL ) { |
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| 113 | SDL_SetError("Passed a NULL mutex"); |
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| 114 | return -1; |
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| 115 | } |
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| 116 | |||
| 117 | /* If we don't own the mutex, we can't unlock it */ |
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| 118 | if ( SDL_ThreadID() != mutex->owner ) { |
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| 119 | SDL_SetError("mutex not owned by this thread"); |
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| 120 | return -1; |
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| 121 | } |
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| 122 | |||
| 123 | if ( mutex->recursive ) { |
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| 124 | --mutex->recursive; |
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| 125 | } else { |
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| 126 | /* The order of operations is important. |
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| 127 | First reset the owner so another thread doesn't lock |
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| 128 | the mutex and set the ownership before we reset it, |
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| 129 | then release the lock semaphore. |
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| 130 | */ |
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| 131 | mutex->owner = 0; |
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| 132 | SDL_SemPost(mutex->sem); |
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| 133 | } |
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| 134 | return 0; |
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| 135 | #endif /* DISABLE_THREADS */ |
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| 136 | } |