Atlas - SDL_syscond.c
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[FILE BEGIN]
1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2025 Sam Lantinga <[email protected]>
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}
129
[FILE END]
(C) 2025 0x4248
(C) 2025 4248 Media and 4248 Systems, All part of 0x4248
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