annotate core/ReceiveAudioThread.cpp @ 117:ada68d50e56a scope-refactoring

ReceiveAudioThread hs been ported to BBB. The scope project now is sending audio locally and receiving it at the same time

#include "ReceiveAudioThread.h"
//initialise static members
AuxiliaryTask ReceiveAudioThread::receiveDataTask=NULL;

void ReceiveAudioThread::dealloc(){
    free(buffer);
    buffer=NULL;
    free(stackBuffer);
    stackBuffer=NULL;
}
void ReceiveAudioThread::wrapWritePointer(){
    //this is not quite a simple wrapping as you wold in a circular buffer,
    //as there is no guarantee the buffer will be full at all times, given that there must alwas be enough space at the end of it
    //to hold a full payload
    // lastValidPointer indicates the last pointer in the buffer containing valid data
    //
    if(writePointer+payloadLength+headerLength>bufferLength){ //if we are going to exceed the length of the buffer with the next reading
        //  lastValidPointer=writePointer+headerLength; //remember where the last valid data are
        //  for(int n=headerLength;n<lastValidPointer; n++){
            //  fprintf(fd2, "%f\n",buffer[n]); //DEBUG
        //  }
        writePointer=0; //and reset to beginning of the buffer
    }
}
void ReceiveAudioThread::pushPayload(int startIndex){ //backup the payload samples that will be overwritten by the new header
    for(int n=0; n<headerLength; n++){
        stackBuffer[n]=buffer[startIndex+n];
    }
}
void ReceiveAudioThread::popPayload(int startIndex){
    for(int n=0; n<headerLength; n++){
        buffer[startIndex+n]=stackBuffer[n];
    }        
}

int ReceiveAudioThread::readUdpToBuffer(){
    if(listening==false || bufferReady==false)
        return 0;
    if(writePointer<0)
        return 0;
    if(1){ //TODO: implement waitUntilReady for UdpServer
//JUCE    if(socket.waitUntilReady(true, waitForSocketTime)){ // waitForSocketTime could have been set to -1 (wait forever),
                                                        // but it would have made it more difficult for the thread to be killed
        pushPayload(writePointer); //backup headerLength samples. This could be skipped if writePointer==0
        //read header+payload
//JUCE        int numBytes=socket.read(buffer+writePointer, bytesToRead,1);
        int numBytes=socket.read(buffer+writePointer, bytesToRead);
            //TODO: do something with the data in the header (e.g.: check that timestamp is sequential,
            // check the channel number)
            //TODO: (if using variable-length payload) validate the actual numBytes read against the size declared in the header
        if(numBytes<0){
            printf("error numBytes1\n");
            return -3; //TODO: something went wrong, you have to discard the rest of the packet!
        }
        if(numBytes==0){//TODO: when inplementing waitUntilReady, this should not happen unless you actually receive a packate of size zero (is it at all possible?)
//        	printf("received 0 bytes\n");
        	return 0;
        }
        if(numBytes != bytesToRead){ //this is equivalent to (numBytes<numBytes)
            printf("error numBytes2: %d\n", numBytes);
            return -4; //TODO: something went wrong, less bytes than expected in the payload.
        }
        if(buffer[writePointer]!=0)
        	return 0; //wrong channel
        //  printf("Received a message of length %d, it was on channel %d and timestamp %d\n", numBytes, (int)buffer[writePointer], (int)buffer[writePointer+1]);
        popPayload(writePointer); //restore headerLength payload samples. This could be skipped if writePointer==0

        //even though we just wrote (payloadLength+headerLength) samples in the buffer,
        //we only increment by payloadLength. This way, next time a socket.read is performed, we will
        //backup the last headerLength samples that we just wrote and we will overwrite them with
        //the header from the new read. After parsing the header we will then restore the backed up samples.
        //This way we guarantee that, apart from the first headerLength samples, buffer is a circular buffer!
        printf("writepointer:%d\n", writePointer);
        writePointer+=payloadLength;

        if(writePointer>lastValidPointer){
            //  lastValidPointer=writePointer+headerLength;
        }
        wrapWritePointer();
        return numBytes;
    }
    return 0; //timeout occurred
}
ReceiveAudioThread::ReceiveAudioThread() :
//JUCE    Thread(threadName),
    socket(0),
    listening(false),
    bufferReady(false),
    threadIsExiting(false),
    buffer(NULL),
    stackBuffer(NULL),
    bufferLength(0),
    lastValidPointer(0),
    sleepTime(2000),
    waitForSocketTime(100),
    threadPriority(95)
{};
ReceiveAudioThread::~ReceiveAudioThread(){
//JUCE    stopThread(1000);
	while(threadRunning){
		sleep(sleepTime*2);	//wait for thread to stop
		std::cout<< "Waiting for receiveAudioTask to stop" << std::endl;
	}
	//TODO: check if thread stopped, otherwise kill it before dealloc
    dealloc();
}
ReceiveAudioThread *gRAT;
void receiveData(){
	gRAT->run();
}
void ReceiveAudioThread::init(int aSamplesPerBlock){
  dealloc();
  //  fd=fopen("output.m","w"); //DEBUG
  //  fprintf(fd,"var=["); //DEBUG
  gRAT=this;
  headerLength=2;
  payloadLength=300; //TODO: make sure that payloadLength and headerLength are the same as the client is sending.
  bufferLength=std::max(headerLength+(payloadLength*4), headerLength+(aSamplesPerBlock*4)); //there are many considerations that can be done here ...
                      //We keep a headerLength padding at the beginning of the array to allow full reads from the socket
  buffer=(float*)malloc(sizeof(float)*bufferLength);
  if(buffer==NULL) // something wrong
    return;
  bufferReady=true;
  lastValidPointer=headerLength+ ((bufferLength-headerLength)/payloadLength)*payloadLength;
  memset(buffer,0,bufferLength*sizeof(float));
  stackBuffer=(float*)malloc(sizeof(float)*headerLength);
  bytesToRead=sizeof(float)*(payloadLength + headerLength);
  writePointer=-1;
  readPointer=0; //TODO: this *4 is sortof a security margin
  sleepTime=payloadLength/(float)44100 /4.0; //set sleepTime so that you do not check too often or too infrequently
	receiveDataTask=BeagleRT_createAuxiliaryTask( receiveData, threadPriority, "receiveDataTask");
//JUCE    startThread(threadPriority);
}

void ReceiveAudioThread::bindToPort(int aPort){
    listening=socket.bindToPort(aPort);
}
bool ReceiveAudioThread::isListening(){
    return listening;
}
float* ReceiveAudioThread::getCurrentBuffer(int length){ // NOTE: this cannot work all the time unless samplesPerBuffer and payloadLength are multiples
    //TODO: make it return the number of samples actually available at the specified location
    if(isListening()==false || length>bufferLength)
        return NULL;
    readPointer+=length;
    if(readPointer>lastValidPointer){
        readPointer=headerLength;
    }
    return buffer+(int)readPointer;
};
int ReceiveAudioThread::getSamplesSrc(float *destination, int length, float samplingRateRatio){//TODO: add interleaved version
    if (!(samplingRateRatio>0 && samplingRateRatio<=2))
        return -2;
    if(isListening()==false)
        return -1;
    if(writePointer<0){ //if writePointer has not been initalized yet ...
        writePointer=2*length;  // do it, so that it starts writing at a safety margin from where we write.
                            // This will help keeping them in sync.
                            //TODO: handle what happens when the remote stream is interrupted and then restarted
    }
    if(length>lastValidPointer) { 
        //not enough samples available, we fill the buffer with what is available, but the destination buffer will not be filled completely
        //at this very moment the other thread might be writing at most one payload into the buffer.
        //To avoid a race condition, we need to let alone the buffer where we are currently writing
        //as writing the payload also temporarily overwrites the previous headerLength samples, we need to account for them as well
        //TODO: This assumes that the writePointer and readPointer do not drift. When doing clock synchronization we will find out that it is not true!
        length=lastValidPointer-payloadLength-headerLength;
        if(length<0) //no samples available at all! 
            return 0;
    }
    for(int n=0; n<length; n++){
        destination[n]=buffer[(int)(0.5+readPointer)];//simple ZOH non-interpolation (nearest neighbour)
        //  fprintf(fd,"%f, %d, %f;\n",readPointer,writePointer,destination[n]); //DEBUG
        readPointer+=samplingRateRatio;
        if((int)(0.5+readPointer)>=lastValidPointer){
            readPointer=readPointer-lastValidPointer+headerLength;
        }
    }
    return readPointer; 
}

bool ReceiveAudioThread::isBufferReady(){
    return bufferReady;
}
void ReceiveAudioThread::startThread(){
	BeagleRT_scheduleAuxiliaryTask(receiveDataTask);
}
void ReceiveAudioThread::stopThread(){
	threadIsExiting=true;
}
bool ReceiveAudioThread::threadShouldExit(){
	return(gShouldStop || threadIsExiting );
}
void ReceiveAudioThread::run(){
    //  fd2=fopen("buffer.m","w"); //DEBUG
    //  fprintf(fd2, "buf=["); //DEBUG
	threadRunning=true;
    while(!threadShouldExit()){ //TODO: check that the socket buffer is empty before starting
        readUdpToBuffer(); // read into the oldBuffer
        usleep(sleepTime);
    }
    threadRunning=false;
    //  fprintf(fd,"];readPointer,writePointer,lastValidPointer,destination]=deal(var(:,1), var(:,2), var(:,3), var(:,4));"); //DEBUG
    //  fclose(fd);//DEBUG
    //  fprintf(fd2,"];");//DEBUG
    //  fclose(fd2); //DEBUG
}