zmq receiver changed from blocking to nonblocking

JAERO/zmq_audioreceiver.cpp

@@ -21,6 +21,13 @@ void ZMQAudioReceiver::Start(QString address, QString topic)
     }
 }
 
+void ZMQAudioReceiver::Stop()
+{
+    running = false;
+    if(!future.isFinished())future.waitForFinished();
+    emit finished();
+}
+
 void ZMQAudioReceiver::process()
 {
     // allocate enough for 96Khz sampling with 1 buffer per second
@@ -32,34 +39,44 @@ void ZMQAudioReceiver::process()
     zmq_setsockopt(subscriber, ZMQ_SUBSCRIBE, _topic.toStdString().c_str(), 5);
 
     char buf [recsize];
-    char topic[20];
     unsigned char rate[4];
     quint32 sampleRate;
+    int received;
 
     running = true;
 
     while(running)
     {
-        zmq_recv(subscriber, topic, 20, 0);
-        int received = zmq_recv(subscriber, rate, 4, ZMQ_DONTWAIT);
+
+        //blocking call alternative for topic, here we wait for the topic.
+        //I guess the sleep has to be less then the idle period between messages???
+        while(((received = zmq_recv(subscriber,  nullptr, 0, ZMQ_DONTWAIT))<0)&&running)
+        {
+            usleep(10000);
+        }
+        if(!running)break;
+
+        //rate message is next
+        received = zmq_recv(subscriber, rate, 4, ZMQ_DONTWAIT);
+        if(!running)break;
         memcpy(&sampleRate, rate, 4);
+
+        //then audio data
         received = zmq_recv(subscriber, buf, recsize, ZMQ_DONTWAIT);
+        if(!running)break;
         if(received>=0)
         {
             QByteArray qdata(buf, received);
             emit recAudio(qdata,sampleRate);
         }
-        else
-        {
-            if(running)
-            {
-                qDebug()<<"zmq_recv error!!!";
-                usleep(100000);
-            }
-        }
+
     }
-}
 
+    if(subscriber)zmq_close(subscriber);
+    if(context)zmq_ctx_destroy(context);
+    subscriber=nullptr;
+    context=nullptr;
+}
 
 ZMQAudioReceiver::ZMQAudioReceiver(QObject *parent):
     QObject(parent),
@@ -81,18 +98,4 @@ void ZMQAudioReceiver::setParameters(QString address, QString topic)
     _topic = topic;
 }
 
-void ZMQAudioReceiver::Stop()
-{
 
-    running = false;
-
-    if(subscriber)zmq_close(subscriber);
-    if(context)zmq_ctx_destroy(context);
-    if(!future.isFinished())future.waitForFinished();
-
-    subscriber=nullptr;
-    context=nullptr;
-
-    emit finished();
-
-}