///////////////////////////////////////////////////////////////////////////

//

// Copyright (c) 2005-2012, Industrial Light & Magic, a division of Lucas

// Digital Ltd. LLC

// 

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

// *       Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

// *       Redistributions in binary form must reproduce the above

// copyright notice, this list of conditions and the following disclaimer

// in the documentation and/or other materials provided with the

// distribution.

// *       Neither the name of Industrial Light & Magic nor the names of

// its contributors may be used to endorse or promote products derived

// from this software without specific prior written permission. 

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

//

///////////////////////////////////////////////////////////////////////////

//-----------------------------------------------------------------------------

//

//	class Semaphore -- implementation for Windows

//

//-----------------------------------------------------------------------------

#include "IlmThreadSemaphore.h"

#include "Iex.h"

#include <string>

#include <assert.h>

#include <iostream>

ILMTHREAD_INTERNAL_NAMESPACE_SOURCE_ENTER

using namespace IEX_NAMESPACE;

namespace {

std::string

errorString ()

{

    LPSTR messageBuffer;

    DWORD bufferLength;

    std::string message;

    //

    // Call FormatMessage() to allow for message 

    // text to be acquired from the system.

    //

    if (bufferLength = FormatMessageA (FORMAT_MESSAGE_ALLOCATE_BUFFER |

				       FORMAT_MESSAGE_IGNORE_INSERTS |

				       FORMAT_MESSAGE_FROM_SYSTEM,

				       0,

				       GetLastError (),

				       MAKELANGID (LANG_NEUTRAL,

						   SUBLANG_DEFAULT),

				       (LPSTR) &messageBuffer,

				       0,

				       NULL))

    {

	message = messageBuffer;

        LocalFree (messageBuffer);

    }

    return message;

}

} // namespace

Semaphore::Semaphore (unsigned int value)

{

    if ((_semaphore = ::CreateSemaphore (0, value, 0x7fffffff, 0)) == 0)

    {

	THROW (LogicExc, "Could not create semaphore "

			 "(" << errorString() << ").");

    }

}

Semaphore::~Semaphore()

{

    bool ok = ::CloseHandle (_semaphore) != FALSE;

    assert (ok);

}

void

Semaphore::wait()

{

    if (::WaitForSingleObject (_semaphore, INFINITE) != WAIT_OBJECT_0)

    {

	THROW (LogicExc, "Could not wait on semaphore "

			 "(" << errorString() << ").");

    }

}

bool

Semaphore::tryWait()

{

    return ::WaitForSingleObject (_semaphore, 0) == WAIT_OBJECT_0;

}

void

Semaphore::post()

{

    if (!::ReleaseSemaphore (_semaphore, 1, 0))

    {

	THROW (LogicExc, "Could not post on semaphore "

			 "(" << errorString() << ").");

    }

}

int

Semaphore::value() const

{

    LONG v = -1;

    if (!::ReleaseSemaphore (_semaphore, 0, &v) || v < 0)

    {

	THROW (LogicExc, "Could not get value of semaphore "

			 "(" << errorString () << ").");

    }

    return v;

}

ILMTHREAD_INTERNAL_NAMESPACE_SOURCE_EXIT