SDL_syscond.cpp
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/*
Simple DirectMedia Layer
Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"
extern "C" {
#include "SDL_thread.h"
}
#include <chrono>
#include <condition_variable>
#include <ratio>
#include <system_error>
#include "SDL_sysmutex_c.h"
struct SDL_cond
{
std::condition_variable_any cpp_cond;
};
/* Create a condition variable */
extern "C"
SDL_cond *
SDL_CreateCond(void)
{
/* Allocate and initialize the condition variable */
try {
SDL_cond * cond = new SDL_cond;
return cond;
} catch (std::system_error & ex) {
SDL_SetError("unable to create a C++ condition variable: code=%d; %s", ex.code(), ex.what());
return NULL;
} catch (std::bad_alloc &) {
SDL_OutOfMemory();
return NULL;
}
}
/* Destroy a condition variable */
extern "C"
void
SDL_DestroyCond(SDL_cond * cond)
{
if (cond) {
delete cond;
}
}
/* Restart one of the threads that are waiting on the condition variable */
extern "C"
int
SDL_CondSignal(SDL_cond * cond)
{
if (!cond) {
SDL_SetError("Passed a NULL condition variable");
return -1;
}
cond->cpp_cond.notify_one();
return 0;
}
/* Restart all threads that are waiting on the condition variable */
extern "C"
int
SDL_CondBroadcast(SDL_cond * cond)
{
if (!cond) {
SDL_SetError("Passed a NULL condition variable");
return -1;
}
cond->cpp_cond.notify_all();
return 0;
}
/* Wait on the condition variable for at most 'ms' milliseconds.
The mutex must be locked before entering this function!
The mutex is unlocked during the wait, and locked again after the wait.
Typical use:
Thread A:
SDL_LockMutex(lock);
while ( ! condition ) {
SDL_CondWait(cond, lock);
}
SDL_UnlockMutex(lock);
Thread B:
SDL_LockMutex(lock);
...
condition = true;
...
SDL_CondSignal(cond);
SDL_UnlockMutex(lock);
*/
extern "C"
int
SDL_CondWaitTimeout(SDL_cond * cond, SDL_mutex * mutex, Uint32 ms)
{
if (!cond) {
SDL_SetError("Passed a NULL condition variable");
return -1;
}
if (!mutex) {
SDL_SetError("Passed a NULL mutex variable");
return -1;
}
try {
std::unique_lock<std::recursive_mutex> cpp_lock(mutex->cpp_mutex, std::adopt_lock_t());
if (ms == SDL_MUTEX_MAXWAIT) {
cond->cpp_cond.wait(
cpp_lock
);
cpp_lock.release();
return 0;
} else {
auto wait_result = cond->cpp_cond.wait_for(
cpp_lock,
std::chrono::duration<Uint32, std::milli>(ms)
);
cpp_lock.release();
if (wait_result == std::cv_status::timeout) {
return SDL_MUTEX_TIMEDOUT;
} else {
return 0;
}
}
} catch (std::system_error & ex) {
SDL_SetError("unable to wait on a C++ condition variable: code=%d; %s", ex.code(), ex.what());
return -1;
}
}
/* Wait on the condition variable forever */
extern "C"
int
SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex)
{
return SDL_CondWaitTimeout(cond, mutex, SDL_MUTEX_MAXWAIT);
}
/* vi: set ts=4 sw=4 expandtab: */
SDL_CondWait
int SDL_CondWait(SDL_cond *cond, SDL_mutex *mutex)
Definition: SDL_syscond.cpp:159
SDL_DestroyCond
void SDL_DestroyCond(SDL_cond *cond)
Definition: SDL_syscond.cpp:60
SDL_sysmutex_c.h
Uint32
uint32_t Uint32
An unsigned 32-bit integer type.
Definition: SDL_stdinc.h:157
SDL_mutex::cpp_mutex
std::recursive_mutex cpp_mutex
Definition: SDL_sysmutex_c.h:27
mutex
static SDL_mutex * mutex
Definition: testlock.c:23
SDL_MUTEX_TIMEDOUT
#define SDL_MUTEX_TIMEDOUT
Definition: SDL_mutex.h:44
SDL_cond
Definition: SDL_syscond.c:31
SDL_thread.h
SDL_CondSignal
int SDL_CondSignal(SDL_cond *cond)
Definition: SDL_syscond.cpp:70
SDL_mutex
Definition: SDL_sysmutex.c:29
SDL_CondWaitTimeout
int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms)
Definition: SDL_syscond.cpp:118
SDL_CreateCond
SDL_cond * SDL_CreateCond(void)
Definition: SDL_syscond.cpp:42
SDL_MUTEX_MAXWAIT
#define SDL_MUTEX_MAXWAIT
Definition: SDL_mutex.h:49
SDL_cond::cond
pthread_cond_t cond
Definition: SDL_syscond.c:34
NULL
#define NULL
Definition: begin_code.h:143
SDL_OutOfMemory
#define SDL_OutOfMemory()
Definition: SDL_error.h:52
SDL_SetError
#define SDL_SetError
Definition: SDL_dynapi_overrides.h:36
timeout
GLbitfield GLuint64 timeout
Definition: SDL_opengl_glext.h:1483
SDL_CondBroadcast
int SDL_CondBroadcast(SDL_cond *cond)
Definition: SDL_syscond.cpp:84
SDL_cond::cpp_cond
std::condition_variable_any cpp_cond
Definition: SDL_syscond.cpp:36