0
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
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4
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5 This library is free software; you can redistribute it and/or
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6 modify it under the terms of the GNU Library General Public
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7 License as published by the Free Software Foundation; either
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8 version 2 of the License, or (at your option) any later version.
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9
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10 This library is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 Library General Public License for more details.
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14
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15 You should have received a copy of the GNU Library General Public
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16 License along with this library; if not, write to the Free
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17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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18
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19 Sam Lantinga
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20 slouken@devolution.com
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21 */
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22
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23 #ifdef SAVE_RCSID
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24 static char rcsid =
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25 "@(#) $Id$";
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26 #endif
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27
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28 #ifdef linux
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29 /* Look to see if glibc is available, and if so, what version */
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30 #include <features.h>
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31
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32 #if (__GLIBC__ == 2) && (__GLIBC_MINOR__ == 0)
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33 #warning Working around a bug in glibc 2.0 pthreads
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34 #undef SDL_USE_PTHREADS
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35 /* The bug is actually a problem where threads are suspended, but don't
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36 wake up when the thread manager sends them a signal. This is a problem
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37 with thread creation too, but it happens less often. :-/
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38 We avoid this by using System V IPC for mutexes.
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39 */
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40 #endif /* glibc 2.0 */
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41 #endif /* linux */
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42
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43 #ifdef SDL_USE_PTHREADS
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44
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45 #include <sys/time.h>
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46 #include <unistd.h>
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47 #include <errno.h>
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48 #include <stdlib.h>
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49 #include <pthread.h>
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50
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51 #include "SDL_error.h"
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52 #include "SDL_thread.h"
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53 #include "SDL_sysmutex_c.h"
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54
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55
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56 #if defined(PTHREAD_NO_RECURSIVE_MUTEX) && !defined(__bsdi__)
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57 #error You need to use the generic condition variable implementation
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58 #endif
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59
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60 struct SDL_cond
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61 {
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62 pthread_cond_t cond;
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63 };
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64
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65 /* Create a condition variable */
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66 SDL_cond * SDL_CreateCond(void)
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67 {
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68 SDL_cond *cond;
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69
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70 cond = (SDL_cond *) malloc(sizeof(SDL_cond));
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71 if ( cond ) {
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72 if ( pthread_cond_init(&cond->cond, NULL) < 0 ) {
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73 SDL_SetError("pthread_cond_init() failed");
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74 free(cond);
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75 cond = NULL;
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76 }
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77 }
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78 return(cond);
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79 }
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80
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81 /* Destroy a condition variable */
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82 void SDL_DestroyCond(SDL_cond *cond)
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83 {
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84 if ( cond ) {
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85 pthread_cond_destroy(&cond->cond);
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86 free(cond);
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87 }
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88 }
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89
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90 /* Restart one of the threads that are waiting on the condition variable */
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91 int SDL_CondSignal(SDL_cond *cond)
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92 {
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93 int retval;
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94
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95 if ( ! cond ) {
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96 SDL_SetError("Passed a NULL condition variable");
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97 return -1;
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98 }
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99
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100 retval = 0;
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101 if ( pthread_cond_signal(&cond->cond) != 0 ) {
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102 SDL_SetError("pthread_cond_signal() failed");
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103 retval = -1;
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104 }
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105 return retval;
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106 }
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107
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108 /* Restart all threads that are waiting on the condition variable */
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109 int SDL_CondBroadcast(SDL_cond *cond)
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110 {
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111 int retval;
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112
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113 if ( ! cond ) {
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114 SDL_SetError("Passed a NULL condition variable");
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115 return -1;
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116 }
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117
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118 retval = 0;
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119 if ( pthread_cond_broadcast(&cond->cond) != 0 ) {
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120 SDL_SetError("pthread_cond_broadcast() failed");
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121 retval = -1;
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122 }
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123 return retval;
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124 }
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125
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126 int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms)
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127 {
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128 int retval;
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129 struct timeval delta;
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130 struct timespec abstime;
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131
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132 if ( ! cond ) {
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133 SDL_SetError("Passed a NULL condition variable");
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134 return -1;
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135 }
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136
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137 gettimeofday(&delta, NULL);
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138
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139 abstime.tv_sec = delta.tv_sec + (ms/1000);
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140 abstime.tv_nsec = (delta.tv_usec+(ms%1000)) * 1000;
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141 if ( abstime.tv_nsec > 1000000 ) {
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142 abstime.tv_sec += 1;
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143 abstime.tv_nsec -= 1000000;
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144 }
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145
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146 tryagain:
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147 retval = pthread_cond_timedwait(&cond->cond, &mutex->id, &abstime);
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148 switch (retval) {
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149 case EINTR:
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150 goto tryagain;
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151 break;
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152 case ETIMEDOUT:
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153 retval = SDL_MUTEX_TIMEDOUT;
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154 break;
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155 case 0:
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156 break;
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157 default:
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158 SDL_SetError("pthread_cond_timedwait() failed");
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159 retval = -1;
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160 break;
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161 }
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162 return retval;
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163 }
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164
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165 /* Wait on the condition variable, unlocking the provided mutex.
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166 The mutex must be locked before entering this function!
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167 */
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168 int SDL_CondWait(SDL_cond *cond, SDL_mutex *mutex)
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169 {
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170 int retval;
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171
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172 if ( ! cond ) {
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173 SDL_SetError("Passed a NULL condition variable");
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174 return -1;
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175 }
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176
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177 retval = 0;
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178 if ( pthread_cond_wait(&cond->cond, &mutex->id) != 0 ) {
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179 SDL_SetError("pthread_cond_wait() failed");
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180 retval = -1;
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181 }
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182 return retval;
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183 }
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184
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185 #else /* Use semaphore implementation */
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186
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187 #include "generic/SDL_syscond.c"
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188
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189 #endif /* SDL_USE_PTHREADS */
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