WinMME based midi input/output for portaudio backend

TODO:

Use MMCSS to elevate thread priorities
Enable/test and fix SYSEX related code

libs/backends/portaudio/winmmemidi_output_device.h

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef WINMME_MIDI_OUTPUT_DEVICE_H
+#define WINMME_MIDI_OUTPUT_DEVICE_H
+
+#include <windows.h>
+#include <mmsystem.h>
+
+#include <stdint.h>
+
+#include <string>
+
+#include <boost/scoped_ptr.hpp>
+
+#include <pbd/ringbuffer.h>
+
+namespace ARDOUR {
+
+class WinMMEMidiOutputDevice {
+public:
+	WinMMEMidiOutputDevice (int index);
+
+	~WinMMEMidiOutputDevice ();
+
+	bool enqueue_midi_event (uint64_t rel_event_time_us,
+	                         const uint8_t* data,
+	                         const size_t size);
+
+	bool start ();
+	bool stop ();
+
+	void set_enabled (bool enable);
+	bool get_enabled ();
+
+	std::string name () const { return m_name; }
+
+private: // Methods
+	bool open (UINT index, std::string& error_msg);
+	bool close (std::string& error_msg);
+
+	bool set_device_name (UINT index);
+
+	std::string get_error_string (MMRESULT error_code);
+
+	bool start_midi_output_thread ();
+	bool stop_midi_output_thread ();
+
+	bool signal (HANDLE semaphore);
+	bool wait (HANDLE semaphore);
+
+	static void* midi_output_thread (void*);
+	void midi_output_thread ();
+
+	bool wait_for_microseconds (int64_t us);
+
+	static void CALLBACK winmm_output_callback (HMIDIOUT handle,
+	                                            UINT msg,
+	                                            DWORD_PTR instance,
+	                                            DWORD_PTR midi_data,
+	                                            DWORD_PTR timestamp);
+
+	void midi_output_callback (UINT msg, DWORD_PTR data, DWORD_PTR timestamp);
+
+private: // Data
+	HMIDIOUT m_handle;
+
+	HANDLE m_queue_semaphore;
+	HANDLE m_sysex_semaphore;
+
+	HANDLE m_timer;
+
+	bool m_started;
+	bool m_enabled;
+
+	std::string m_name;
+
+	pthread_t m_output_thread_handle;
+
+	bool m_thread_running;
+	bool m_thread_quit;
+
+	boost::scoped_ptr<RingBuffer<uint8_t> > m_midi_buffer;
+};
+
+} // namespace ARDOUR
+
+#endif // WINMME_MIDI_OUTPUT_DEVICE_H