libcruft-util/thread/semaphore_win32.cpp

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/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Copyright 2018 Danny Robson <danny@nerdcruft.net>
*/
#include "semaphore_win32.hpp"
#include "../win32/except.hpp"
#include "../win32/windows.hpp"
#include "../debug.hpp"
using cruft::thread::semaphore;
///////////////////////////////////////////////////////////////////////////////
semaphore::semaphore ():
semaphore (1)
{ ; }
//-----------------------------------------------------------------------------
semaphore::semaphore (value_type initial):
m_handle (
win32::error::try_call (
CreateSemaphore,
nullptr,
initial,
std::numeric_limits<LONG>::max (),
nullptr
)
)
{
m_value = initial;
}
///////////////////////////////////////////////////////////////////////////////
semaphore::value_type
semaphore::acquire (value_type const count)
{
CHECK_GE (count, 0);
for (value_type i = 0; i < count; ++i) {
if (WAIT_OBJECT_0 != WaitForSingleObject(m_handle.native(), INFINITE))
win32::error::throw_code();
--m_value;
}
return m_value;
}
//-----------------------------------------------------------------------------
semaphore::value_type
semaphore::acquire (void)
{
return acquire (1);
}
//-----------------------------------------------------------------------------
semaphore::value_type
semaphore::release (value_type count)
{
LONG previous;
for (value_type i = 0; i < count; ++i) {
if (!ReleaseSemaphore (m_handle.native(), count, &previous))
win32::error::throw_code ();
++m_value;
}
return previous + 1;
}
//-----------------------------------------------------------------------------
semaphore::value_type
semaphore::release (void)
{
return release (1);
}
///////////////////////////////////////////////////////////////////////////////
semaphore::value_type
semaphore::value (void) const
{
return m_value;
}
//-----------------------------------------------------------------------------
semaphore::value_type
semaphore::operator++ (void)
{
return release ();
}
//-----------------------------------------------------------------------------
semaphore::value_type
semaphore::operator-- (void)
{
return acquire ();
}