Wrapper Library for Windows MIDI API

/*******************************************************************************
  MIDIInDevice.cpp - Implementation for CMIDIInDevice and related 
                     classes.
 
    Copyright (c) 2008 Leslie Sanford

    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the "Software"), to deal in the Software without
    restriction, including without limitation the rights to use,
    copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following
    conditions:

    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
    OTHER DEALINGS IN THE SOFTWARE.

    Contact: Leslie Sanford (jabberdabber@hotmail.com)

    Last modified: 01/23/2008
 ******************************************************************************/


//--------------------------------------------------------------------
// Dependencies
//--------------------------------------------------------------------


#include "MIDIInDevice.h"
#include "midi.h"


//--------------------------------------------------------------------
// Using declarations
//--------------------------------------------------------------------


using midi::CMIDIInDevice;
using midi::CMIDIReceiver;
using midi::CMIDIInException;


//--------------------------------------------------------------------
// CMIDIInHeader implementation
//--------------------------------------------------------------------


// Constructor
CMIDIInDevice::CMIDIInHeader::CMIDIInHeader(HMIDIIN DevHandle,
                                            LPSTR Buffer, 
                                            DWORD BufferLength) :
m_DevHandle(DevHandle)
{
    // Initialize header
    m_MIDIHdr.lpData         = Buffer;
    m_MIDIHdr.dwBufferLength = BufferLength;
    m_MIDIHdr.dwFlags        = 0;

    // Prepare header
    MMRESULT Result = ::midiInPrepareHeader(DevHandle, &m_MIDIHdr,
                                            sizeof m_MIDIHdr);

    // If an error occurred, throw exception
    if(Result != MMSYSERR_NOERROR)
    {
        throw CMIDIInException(Result);
    }
}


// Destructor
CMIDIInDevice::CMIDIInHeader::~CMIDIInHeader()
{
    ::midiInUnprepareHeader(m_DevHandle, &m_MIDIHdr, 
                            sizeof m_MIDIHdr);
}


// Add system exclusive buffer to queue
void CMIDIInDevice::CMIDIInHeader::AddSysExBuffer()
{
    MMRESULT Result = ::midiInAddBuffer(m_DevHandle, &m_MIDIHdr,
                                        sizeof m_MIDIHdr);

    // If an error occurred, throw exception
    if(Result != MMSYSERR_NOERROR)
    {
        throw CMIDIInException(Result);
    }
}


//--------------------------------------------------------------------
// CHeaderQueue implementation
//--------------------------------------------------------------------


// Constructor
CMIDIInDevice::CHeaderQueue::CHeaderQueue()
{
    ::InitializeCriticalSection(&m_CriticalSection);
}


// Destructor
CMIDIInDevice::CHeaderQueue::~CHeaderQueue()
{
    RemoveAll();

    ::DeleteCriticalSection(&m_CriticalSection);
}


// Add header to queue
void CMIDIInDevice::CHeaderQueue::AddHeader(
                                 CMIDIInDevice::CMIDIInHeader *Header)
{
    ::EnterCriticalSection(&m_CriticalSection);

    m_HdrQueue.push(Header);

    ::LeaveCriticalSection(&m_CriticalSection);
}


// Remove header from queue
void CMIDIInDevice::CHeaderQueue::RemoveHeader()
{
    ::EnterCriticalSection(&m_CriticalSection);

    if(!m_HdrQueue.empty())
    {
        delete m_HdrQueue.front();
        m_HdrQueue.pop();
    }

    ::LeaveCriticalSection(&m_CriticalSection);
}


// Empty header queue
void CMIDIInDevice::CHeaderQueue::RemoveAll()
{
    ::EnterCriticalSection(&m_CriticalSection);

    while(!m_HdrQueue.empty())
    {
        delete m_HdrQueue.front();
        m_HdrQueue.pop();
    }

    ::LeaveCriticalSection(&m_CriticalSection);
}


// Determines if the header queue is empty
bool CMIDIInDevice::CHeaderQueue::IsEmpty()
{
    bool Result;

    ::EnterCriticalSection(&m_CriticalSection);

    Result = m_HdrQueue.empty();

    ::LeaveCriticalSection(&m_CriticalSection);

    return Result;
}


//--------------------------------------------------------------------
// CMIDIInDevice implementation
//--------------------------------------------------------------------


// Constructs CMIDIInDevice object in an closed state
CMIDIInDevice::CMIDIInDevice() :
m_Receiver(0),
m_State(CLOSED)
{
    // If we are unable to create signalling event, throw exception
    if(!CreateEvent())
    {
        throw CMIDIInEventFailure();
    }
}


// Constructs CMIDIInDevice object in an closed state and initializes the 
// MIDI receiver
CMIDIInDevice::CMIDIInDevice(CMIDIReceiver &Receiver) :
m_Receiver(&Receiver),
m_State(CLOSED)
{
    // If we are unable to create signalling event, throw exception
    if(!CreateEvent())
    {
        throw CMIDIInEventFailure();
    }
}


// Constructs CMIDIInDevice object in an opened state
CMIDIInDevice::CMIDIInDevice(UINT DeviceId, CMIDIReceiver &Receiver) :
m_Receiver(&Receiver),
m_State(CLOSED)
{
    // Open device
    Open(DeviceId);

    // If we are unable to create signalling event, throw exception
    if(!CreateEvent())
    {
        Close();
        throw CMIDIInEventFailure();
    }
}


// Destruction
CMIDIInDevice::~CMIDIInDevice()
{
    // Close device
    Close();

    // Close handle to signalling event
    ::CloseHandle(m_Event);
}


// Opens the MIDI input device
void CMIDIInDevice::Open(UINT DeviceId)
{
    // Makes sure the previous device, if any, is closed before 
    // opening another one
    Close();

    // Open MIDI input device
    MMRESULT Result = ::midiInOpen(&m_DevHandle, DeviceId, 
                                  reinterpret_cast<DWORD>(MidiInProc),
                                  reinterpret_cast<DWORD>(this),
                                  CALLBACK_FUNCTION);

    // If we are able to open the device, change state
    if(Result == MMSYSERR_NOERROR)
    {
        m_State = OPENED;
    }
    // Else opening failed, throw exception
    else
    {
        throw CMIDIInException(Result);
    }
}


// Closes the MIDI input device
void CMIDIInDevice::Close()
{
    // If the device is recording, stop recording before closing the 
    // device
    if(m_State == RECORDING)
    {
        StopRecording();
    }

    // If the device is opened...
    if(m_State == OPENED)
    {
        // Close the device
        MMRESULT Result = ::midiInClose(m_DevHandle);

        // If a failure occurred, throw exception
        if(Result != MMSYSERR_NOERROR)
        {
            throw CMIDIInException(Result);
        }

        // Change state
        m_State = CLOSED;
    }
}


// Adds a buffer for receiving system exclusive messages
void CMIDIInDevice::AddSysExBuffer(LPSTR Buffer, DWORD BufferLength)
{
    CMIDIInHeader *Header;

    try
    {
        // Create new header
        Header = new CMIDIInHeader(m_DevHandle, Buffer, BufferLength);
    }
    // If memory allocation failed, throw exception
    catch(const std::bad_alloc &)
    {
        throw CMIDIInMemFailure();
    }
    // If preparation for the header failed, rethrow exception
    catch(const CMIDIInDevice &)
    {
        throw;
    }

    try
    {
        // Add header to queue
        Header->AddSysExBuffer();
        m_HdrQueue.AddHeader(Header);
    }
    // If we are unable to add the buffer to the queue, delete header
    // and throw exception
    catch(const CMIDIInDevice &)
    {
        delete Header;
        throw;
    }
}


// Starts the recording process
void CMIDIInDevice::StartRecording()
{
    // Only begin recording if the MIDI input device has been opened
    if(m_State == OPENED)
    { 
        // Change state
        m_State = RECORDING;

        m_Thread = ::AfxBeginThread((AFX_THREADPROC)HeaderProc, this);

        // Start recording
        MMRESULT Result = ::midiInStart(m_DevHandle);

        // If recording attempt failed...
        if(Result != MMSYSERR_NOERROR)
        {
            // Revert back to opened state
            m_State = OPENED;

            // Signal the worker thread to finish
            ::SetEvent(m_Event);

			::WaitForSingleObject(m_Thread->m_hThread, INFINITE);

            // Throw exception
            throw CMIDIInException(Result);
        }
    }
}


// Stops the recording process
void CMIDIInDevice::StopRecording()
{
    // If the device is in fact recording...
    if(m_State == RECORDING)
    {
        // Change state
        m_State = OPENED;

        // Signal the worker thread to finish
        ::SetEvent(m_Event);

		::WaitForSingleObject(m_Thread->m_hThread, INFINITE);

        // Reset the MIDI input device
        ::midiInReset(m_DevHandle);

        // Empty header queue
        m_HdrQueue.RemoveAll();
    }
}


// Registers the MIDI receiver. Returns the previous receiver.
CMIDIReceiver *CMIDIInDevice::SetReceiver(CMIDIReceiver &Receiver)
{
    CMIDIReceiver *PrevReceiver = m_Receiver;

    m_Receiver = &Receiver;

    return PrevReceiver;
}


// Determines if the MIDI input device is opened
bool CMIDIInDevice::IsOpen() const
{
    return ((m_State == OPENED) || (m_State == RECORDING));
}


// Determines if the MIDI input device is recording
bool CMIDIInDevice::IsRecording() const
{
    return (m_State == RECORDING);
}


// Gets Id for this device
UINT CMIDIInDevice::GetDevID() const
{
    UINT DeviceID;
    MMRESULT Result = ::midiInGetID(m_DevHandle, &DeviceID);

    if(Result != MMSYSERR_NOERROR)
    {
        throw CMIDIInException(Result);
    }

    return DeviceID;
}


// Gets the capabilities of a particular MIDI input device
void CMIDIInDevice::GetDevCaps(UINT DeviceId, MIDIINCAPS &Caps)
{
    MMRESULT Result = ::midiInGetDevCaps(DeviceId, &Caps, 
                                         sizeof Caps);

    // If we are not able to retrieve device capabilities, throw 
    // exception
    if(Result != MMSYSERR_NOERROR)
    {
        throw CMIDIInException(Result);
    }
}


// Creates event for signalling header thread
bool CMIDIInDevice::CreateEvent()
{
    bool Result = true;

    m_Event = ::CreateEvent(NULL, FALSE, FALSE, NULL);

    // If event creation failed, record failure
    if(m_Event == NULL)
    {
        Result = false;
    }

    return Result;
}


// Called by Windows when a MIDI input event occurs
void CALLBACK CMIDIInDevice::MidiInProc(HMIDIIN MidiIn, UINT Msg,
                                        DWORD_PTR Instance, DWORD_PTR Param1,
                                        DWORD_PTR Param2)
{
    CMIDIInDevice *Device;
    
    Device = reinterpret_cast<CMIDIInDevice *>(Instance);

    if(Device->m_Receiver != 0)
    {
        switch(Msg)
        {
        case MIM_DATA:      // Short message received
            Device->m_Receiver->ReceiveMsg(Param1, Param2);
            break;

        case MIM_ERROR:     // Invalid short message received
            Device->m_Receiver->OnError(Param1, Param2);
            break;

        case MIM_LONGDATA:  // System exclusive message received
            if(Device->m_State == RECORDING)
            {
                // Retrieve data, send it to receiver, and notify header
                // thread that we are done with the system exclusive 
                // message
                MIDIHDR *MidiHdr = reinterpret_cast<MIDIHDR *>(Param1);
                Device->m_Receiver->ReceiveMsg(MidiHdr->lpData, 
                                               MidiHdr->dwBytesRecorded, 
                                               Param2);
                ::SetEvent(Device->m_Event);
            }
            break;

        case MIM_LONGERROR: // Invalid system exclusive message received
            if(Device->m_State == RECORDING)
            {
                // Retrieve data, send it to receiver, and notify header
                // thread that we are done with the system exclusive 
                // message
                MIDIHDR *MidiHdr = reinterpret_cast<MIDIHDR *>(Param1);
                Device->m_Receiver->OnError(MidiHdr->lpData,
                                            MidiHdr->dwBytesRecorded,
                                            Param2);
                ::SetEvent(Device->m_Event);
            }
            break;
        }
    }
}


// Header worker thread
DWORD CMIDIInDevice::HeaderProc(LPVOID Parameter)
{
    CMIDIInDevice *Device; 
    
    Device = reinterpret_cast<CMIDIInDevice *>(Parameter);

    // Continue while the MIDI input device is recording
    while(Device->m_State == RECORDING)
    {
        ::WaitForSingleObject(Device->m_Event, INFINITE);

        // Make sure we are still recording
        if(Device->m_State == RECORDING)
        {
            // Remove the finished header
            Device->m_HdrQueue.RemoveHeader();
        }
    }

    return 0;
}