comparison core/Midi.cpp @ 181:391ad036557d

Basic Midi input implementation

+/*
+ * Midi.cpp
+ *
+ *  Created on: 15 Jan 2016
+ *      Author: giulio
+ */
+
+#include "Midi.h"
+#include <fcntl.h>
+#include <errno.h>
+
+bool Midi::staticConstructed;
+AuxiliaryTask Midi::midiInputTask;
+AuxiliaryTask Midi::midiOutputTask;
+std::vector<Midi *> Midi::objAddrs(0);
+
+Midi::Midi(){
+	outputPort = -1;
+	inputPort = -1;
+	size_t inputBytesInitialSize = 1000;
+	inputBytes.resize(inputBytesInitialSize);
+	inputBytesWritePointer = 0;
+	inputBytesReadPointer = inputBytes.size() - 1;
+	if(!staticConstructed){
+		staticConstructor();
+	}
+}
+
+void Midi::staticConstructor(){
+	staticConstructed = true;
+	midiInputTask = BeagleRT_createAuxiliaryTask(Midi::midiInputLoop, 50, "MidiInput");
+	midiOutputTask = BeagleRT_createAuxiliaryTask(Midi::midiInputLoop, 50, "MidiOutupt");
+}
+
+Midi::~Midi(){}
+
+void Midi::midiInputLoop(){
+	printf("Midi input loop %d\n", objAddrs.size());
+	for(unsigned int n = 0; n < objAddrs.size(); n++){
+		printf("In the for\n");
+		objAddrs[n] -> readInputLoop();
+	}
+}
+
+void Midi::readInputLoop(){
+	while(!gShouldStop){
+		int maxBytesToRead = inputBytes.size() - inputBytesWritePointer;
+		int ret = read(inputPort, &inputBytes[inputBytesWritePointer], sizeof(midi_byte_t)*maxBytesToRead);
+		static int count = 0;
+		count++;
+		if(ret < 0){
+			if(errno != EAGAIN){ // read() would return EAGAIN when no data are available to read just now
+				rt_printf("Error while reading midi %d\n", errno);
+			}
+			usleep(1000);
+			continue;
+		}
+		inputBytesWritePointer += ret;
+		if(inputBytesWritePointer == inputBytes.size()){ //wrap pointer around
+			inputBytesWritePointer = 0;
+		}
+		if(ret < maxBytesToRead){ //no more data to retrieve at the moment
+			usleep(1000);
+		} // otherwise there might be more data ready to be read, so don't sleep
+	}
+}
+
+int Midi::readFrom(int port){
+	objAddrs.push_back(this);
+	inputPort = open("/dev/midi1", O_RDONLY | O_NONBLOCK | O_NOCTTY);
+	if(inputPort < 0){
+		printf("Error occurred while opening midi port %d: %d", port, inputPort);
+		return -1;
+	} else {
+		printf("Reading from port %d\n", inputPort);
+		BeagleRT_scheduleAuxiliaryTask(midiInputTask);
+		return 1;
+	}
+}
+
+int  Midi::getInput(){
+	if(inputPort < 0)
+		return -2;
+	if(inputBytesReadPointer == inputBytesWritePointer){
+		return -1; // no bytes to read
+	}
+	midi_byte_t inputMessage = inputBytes[inputBytesReadPointer++];
+	if(inputBytesReadPointer == inputBytes.size()){ // wrap pointer
+		inputBytesReadPointer = 0;
+	}
+	return inputMessage;
+}