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/**
* OpenAL cross platform audio library
* Copyright (C) 1999-2007 by authors.
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
* Or go to http://www.gnu.org/copyleft/lgpl.html
*/
#include "config.h"
#include "opthelpers.h"
#include "threads.h"
#include <system_error>
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <limits>
namespace al {
semaphore::semaphore(unsigned int initial)
{
if(initial > static_cast<unsigned int>(std::numeric_limits<int>::max()))
throw std::system_error(std::make_error_code(std::errc::value_too_large));
mSem = CreateSemaphore(nullptr, initial, std::numeric_limits<int>::max(), nullptr);
if(mSem == nullptr)
throw std::system_error(std::make_error_code(std::errc::resource_unavailable_try_again));
}
semaphore::~semaphore()
{ CloseHandle(mSem); }
void semaphore::post()
{
if(!ReleaseSemaphore(static_cast<HANDLE>(mSem), 1, nullptr))
throw std::system_error(std::make_error_code(std::errc::value_too_large));
}
void semaphore::wait() noexcept
{ WaitForSingleObject(static_cast<HANDLE>(mSem), INFINITE); }
bool semaphore::try_wait() noexcept
{ return WaitForSingleObject(static_cast<HANDLE>(mSem), 0) == WAIT_OBJECT_0; }
} // namespace al
#else
/* Do not try using libdispatch on systems where it is absent. */
#if defined(AL_APPLE_HAVE_DISPATCH)
namespace al {
semaphore::semaphore(unsigned int initial)
{
mSem = dispatch_semaphore_create(initial);
if(!mSem)
throw std::system_error(std::make_error_code(std::errc::resource_unavailable_try_again));
}
semaphore::~semaphore()
{ dispatch_release(mSem); }
void semaphore::post()
{ dispatch_semaphore_signal(mSem); }
void semaphore::wait() noexcept
{ dispatch_semaphore_wait(mSem, DISPATCH_TIME_FOREVER); }
bool semaphore::try_wait() noexcept
{ return dispatch_semaphore_wait(mSem, DISPATCH_TIME_NOW) == 0; }
} // namespace al
#else /* !__APPLE__ */
#include <cerrno>
namespace al {
semaphore::semaphore(unsigned int initial)
{
if(sem_init(&mSem, 0, initial) != 0)
throw std::system_error(std::make_error_code(std::errc::resource_unavailable_try_again));
}
semaphore::~semaphore()
{ sem_destroy(&mSem); }
void semaphore::post()
{
if(sem_post(&mSem) != 0)
throw std::system_error(std::make_error_code(std::errc::value_too_large));
}
void semaphore::wait() noexcept
{
while(sem_wait(&mSem) == -1 && errno == EINTR) {
}
}
bool semaphore::try_wait() noexcept
{ return sem_trywait(&mSem) == 0; }
} // namespace al
#endif /* __APPLE__ */
#endif /* _WIN32 */
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