portaudio/bindings/cpp/include/portaudiocpp/MemFunCallbackStream.hxx

#ifndef INCLUDED_PORTAUDIO_MEMFUNCALLBACKSTREAM_HXX
#define INCLUDED_PORTAUDIO_MEMFUNCALLBACKSTREAM_HXX

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

#include "portaudio.h"

#include "portaudiocpp/CallbackStream.hxx"
#include "portaudiocpp/CallbackInterface.hxx"
#include "portaudiocpp/StreamParameters.hxx"
#include "portaudiocpp/Exception.hxx"
#include "portaudiocpp/InterfaceCallbackStream.hxx"

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

namespace portaudio
{


	//////
	/// @brief Callback stream using a class's member function as a callback. Template argument T is the type of the 
	/// class of which a member function is going to be used.
	///
	/// Example usage:
	/// @verbatim MemFunCallback<MyClass> stream = MemFunCallbackStream(parameters, *this, &MyClass::myCallbackFunction); @endverbatim
	//////
	template<typename T>
	class MemFunCallbackStream : public CallbackStream
	{
	public:
		typedef int (T::*CallbackFunPtr)(const void *, void *, unsigned long, const PaStreamCallbackTimeInfo *, 
			PaStreamCallbackFlags);

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

		MemFunCallbackStream()
		{
		}

		MemFunCallbackStream(const StreamParameters &parameters, T &instance, CallbackFunPtr memFun) : adapter_(instance, memFun)
		{
			open(parameters);
		}

		~MemFunCallbackStream()
		{
			close();
		}

		void open(const StreamParameters &parameters, T &instance, CallbackFunPtr memFun)
		{
			// XXX:	need to check if already open?

			adapter_.init(instance, memFun);
			open(parameters);
		}

	private:
		MemFunCallbackStream(const MemFunCallbackStream &); // non-copyable
		MemFunCallbackStream &operator=(const MemFunCallbackStream &); // non-copyable

		//////
		/// @brief Inner class which adapts a member function callback to a CallbackInterface compliant 
		/// class (so it can be adapted using the paCallbackAdapter function).
		//////
		class MemFunToCallbackInterfaceAdapter : public CallbackInterface
		{
		public:
			MemFunToCallbackInterfaceAdapter() {}
			MemFunToCallbackInterfaceAdapter(T &instance, CallbackFunPtr memFun) : instance_(&instance), memFun_(memFun) {}

			void init(T &instance, CallbackFunPtr memFun)
			{
				instance_ = &instance;
				memFun_ = memFun;
			}

			int paCallbackFun(const void *inputBuffer, void *outputBuffer, unsigned long numFrames, 
				const PaStreamCallbackTimeInfo *timeInfo, PaStreamCallbackFlags statusFlags)
			{
				return (instance_->*memFun_)(inputBuffer, outputBuffer, numFrames, timeInfo, statusFlags);
			}

		private:
			T *instance_;
			CallbackFunPtr memFun_;
		};

		MemFunToCallbackInterfaceAdapter adapter_;

		void open(const StreamParameters &parameters)
		{
			PaError err = Pa_OpenStream(&stream_, parameters.inputParameters().paStreamParameters(), parameters.outputParameters().paStreamParameters(), 
				parameters.sampleRate(), parameters.framesPerBuffer(), parameters.flags(), &impl::callbackInterfaceToPaCallbackAdapter, 
				static_cast<void *>(&adapter_));

			if (err != paNoError)
				throw PaException(err);
		}
	};


} // portaudio

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

#endif // INCLUDED_PORTAUDIO_MEMFUNCALLBACKSTREAM_HXX