feat(istream): implement TCP using ofxTCPServer

the ofxNetwork API is actually quite hard to use (as the API) but since
it is simplified, we are using it anyway

Xcode/ESP/src/istream.cpp

@@ -324,3 +324,60 @@ void FirmataStream::update() {
         }
     }
 }
+
+bool TcpInputStream::start() {
+    server_.setup(port_num_);
+    server_.setMessageDelimiter("\n");
+
+    reading_thread_.reset(new std::thread([this]() {
+        // Should sleep a bit here
+        int sleep_time = 10;
+        ofLog() << "TCP input streams are checked every " << sleep_time << " ms";
+        while (has_started_) {
+            while (true) {
+                std::this_thread::sleep_for(
+                    std::chrono::milliseconds(sleep_time));
+                for (int i = 0; i < server_.getLastID(); i++) {
+                    if (server_.isClientConnected(i)) {
+                        string str = server_.receive(i);
+                        if (str != "") {
+                            parseInput(str);
+                        }
+                    }
+                }
+            }
+        }
+    }));
+    return true;
+}
+
+void TcpInputStream::parseInput(const string& buffer) {
+    if (data_ready_callback_ != nullptr) {
+        istringstream iss(buffer);
+        vector<double> data;
+        double d;
+
+        while (iss >> d)
+            data.push_back(d);
+
+        if (data.size() > 0) {
+            data = normalize(data);
+
+            GRT::MatrixDouble matrix;
+            matrix.push_back(data);
+
+            data_ready_callback_(matrix);
+        }
+    }
+}
+
+void TcpInputStream::stop() {
+    if (reading_thread_ != nullptr && reading_thread_->joinable()) {
+        reading_thread_->join();
+    }
+    server_.close();
+}
+
+int TcpInputStream::getNumInputDimensions() {
+    return dim_;
+}

Xcode/ESP/src/istream.h

@@ -11,6 +11,7 @@
 
 #include "GRT/GRT.h"
 #include "ofMain.h"
+#include "ofxNetwork.h"
 #include "stream.h"
 
 #include <cstdint>
@@ -253,3 +254,27 @@ class FirmataStream : public InputStream {
     unique_ptr<std::thread> update_thread_;
     void update();
 };
+
+// Forward declaration.
+class ofxTCPServer;
+
+/**
+ @brief Listening for data inputs over a TCP socket.
+ */
+class TcpInputStream : public InputStream {
+  public:
+    TcpInputStream(int port_num, int dimension)
+        : port_num_(port_num), dim_(dimension) {
+    }
+
+    virtual bool start() final;
+    virtual void stop() final;
+    virtual int getNumInputDimensions() final;
+
+  private:
+    void parseInput(const string& buffer);
+    ofxTCPServer server_;
+    unique_ptr<std::thread> reading_thread_;
+    int port_num_;
+    int dim_;
+};