1 /* 2 SDL - Simple DirectMedia Layer 3 Copyright (C) 1997-2012 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 (at) libsdl.org 21 */ 22 #include "SDL_config.h" 23 24 /* RISC OS implementations uses pthreads based on linux code */ 25 26 #if SDL_THREADS_DISABLED 27 #include "../generic/SDL_syscond.c" 28 #else 29 #include <sys/time.h> 30 #include <unistd.h> 31 #include <pthread.h> 32 33 #include "SDL_thread.h" 34 #include "SDL_sysmutex_c.h" 35 36 struct SDL_cond 37 { 38 pthread_cond_t cond; 39 }; 40 41 /* Create a condition variable */ 42 SDL_cond * SDL_CreateCond(void) 43 { 44 SDL_cond *cond; 45 46 cond = (SDL_cond *) SDL_malloc(sizeof(SDL_cond)); 47 if ( cond ) { 48 if ( pthread_cond_init(&cond->cond, NULL) < 0 ) { 49 SDL_SetError("pthread_cond_init() failed"); 50 SDL_free(cond); 51 cond = NULL; 52 } 53 } 54 return(cond); 55 } 56 57 /* Destroy a condition variable */ 58 void SDL_DestroyCond(SDL_cond *cond) 59 { 60 if ( cond ) { 61 pthread_cond_destroy(&cond->cond); 62 SDL_free(cond); 63 } 64 } 65 66 /* Restart one of the threads that are waiting on the condition variable */ 67 int SDL_CondSignal(SDL_cond *cond) 68 { 69 int retval; 70 71 if ( ! cond ) { 72 SDL_SetError("Passed a NULL condition variable"); 73 return -1; 74 } 75 76 retval = 0; 77 if ( pthread_cond_signal(&cond->cond) != 0 ) { 78 SDL_SetError("pthread_cond_signal() failed"); 79 retval = -1; 80 } 81 return retval; 82 } 83 84 /* Restart all threads that are waiting on the condition variable */ 85 int SDL_CondBroadcast(SDL_cond *cond) 86 { 87 int retval; 88 89 if ( ! cond ) { 90 SDL_SetError("Passed a NULL condition variable"); 91 return -1; 92 } 93 94 retval = 0; 95 if ( pthread_cond_broadcast(&cond->cond) != 0 ) { 96 SDL_SetError("pthread_cond_broadcast() failed"); 97 retval = -1; 98 } 99 return retval; 100 } 101 102 int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms) 103 { 104 int retval; 105 struct timeval delta; 106 struct timespec abstime; 107 108 if ( ! cond ) { 109 SDL_SetError("Passed a NULL condition variable"); 110 return -1; 111 } 112 113 gettimeofday(&delta, NULL); 114 115 abstime.tv_sec = delta.tv_sec + (ms/1000); 116 abstime.tv_nsec = (delta.tv_usec + (ms%1000) * 1000) * 1000; 117 if ( abstime.tv_nsec > 1000000000 ) { 118 abstime.tv_sec += 1; 119 abstime.tv_nsec -= 1000000000; 120 } 121 122 tryagain: 123 retval = pthread_cond_timedwait(&cond->cond, &mutex->id, &abstime); 124 switch (retval) { 125 case EINTR: 126 goto tryagain; 127 break; 128 case ETIMEDOUT: 129 retval = SDL_MUTEX_TIMEDOUT; 130 break; 131 case 0: 132 break; 133 default: 134 SDL_SetError("pthread_cond_timedwait() failed"); 135 retval = -1; 136 break; 137 } 138 return retval; 139 } 140 141 /* Wait on the condition variable, unlocking the provided mutex. 142 The mutex must be locked before entering this function! 143 */ 144 int SDL_CondWait(SDL_cond *cond, SDL_mutex *mutex) 145 { 146 int retval; 147 148 if ( ! cond ) { 149 SDL_SetError("Passed a NULL condition variable"); 150 return -1; 151 } 152 153 retval = 0; 154 if ( pthread_cond_wait(&cond->cond, &mutex->id) != 0 ) { 155 SDL_SetError("pthread_cond_wait() failed"); 156 retval = -1; 157 } 158 return retval; 159 } 160 #endif 161
