keii.dev
1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20*/
21#include "SDL_internal.h"
22
23#include <sys/time.h>
24#include <time.h>
25#include <unistd.h>
26#include <errno.h>
27#include <pthread.h>
28
29#include "SDL_sysmutex_c.h"
30
31struct SDL_Condition
32{
33 pthread_cond_t cond;
34};
35
36// Create a condition variable
37SDL_Condition *SDL_CreateCondition(void)
38{
39 SDL_Condition *cond;
40
41 cond = (SDL_Condition *)SDL_malloc(sizeof(SDL_Condition));
42 if (cond) {
43 if (pthread_cond_init(&cond->cond, NULL) != 0) {
44 SDL_SetError("pthread_cond_init() failed");
45 SDL_free(cond);
46 cond = NULL;
47 }
48 }
49 return cond;
50}
51
52// Destroy a condition variable
53void SDL_DestroyCondition(SDL_Condition *cond)
54{
55 if (cond) {
56 pthread_cond_destroy(&cond->cond);
57 SDL_free(cond);
58 }
59}
60
61// Restart one of the threads that are waiting on the condition variable
62void SDL_SignalCondition(SDL_Condition *cond)
63{
64 if (!cond) {
65 return;
66 }
67
68 pthread_cond_signal(&cond->cond);
69}
70
71// Restart all threads that are waiting on the condition variable
72void SDL_BroadcastCondition(SDL_Condition *cond)
73{
74 if (!cond) {
75 return;
76 }
77
78 pthread_cond_broadcast(&cond->cond);
79}
80
81bool SDL_WaitConditionTimeoutNS(SDL_Condition *cond, SDL_Mutex *mutex, Sint64 timeoutNS)
82{
83#ifndef HAVE_CLOCK_GETTIME
84 struct timeval delta;
85#endif
86 struct timespec abstime;
87
88 if (!cond || !mutex) {
89 return true;
90 }
91
92 if (timeoutNS < 0) {
93 return (pthread_cond_wait(&cond->cond, &mutex->id) == 0);
94 }
95
96#ifdef HAVE_CLOCK_GETTIME
97 clock_gettime(CLOCK_REALTIME, &abstime);
98
99 abstime.tv_sec += (timeoutNS / SDL_NS_PER_SECOND);
100 abstime.tv_nsec += (timeoutNS % SDL_NS_PER_SECOND);
101#else
102 gettimeofday(&delta, NULL);
103
104 abstime.tv_sec = delta.tv_sec + (timeoutNS / SDL_NS_PER_SECOND);
105 abstime.tv_nsec = SDL_US_TO_NS(delta.tv_usec) + (timeoutNS % SDL_NS_PER_SECOND);
106#endif
107 while (abstime.tv_nsec >= 1000000000) {
108 abstime.tv_sec += 1;
109 abstime.tv_nsec -= 1000000000;
110 }
111
112 bool result;
113 int rc;
114tryagain:
115 rc = pthread_cond_timedwait(&cond->cond, &mutex->id, &abstime);
116 switch (rc) {
117 case EINTR:
118 goto tryagain;
119 // break; -Wunreachable-code-break
120 case ETIMEDOUT:
121 result = false;
122 break;
123 default:
124 result = true;
125 break;
126 }
127 return result;
128}