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      1 /*
      2     SDL - Simple DirectMedia Layer
      3     Copyright (C) 1997-2006 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