first attempt at networking (does not work)

README.md

@@ -31,6 +31,6 @@ meson build server # for server only
 
 ## Running
 ```shell
-./build/client
-./build/server
+./build/client # for client application
+./build/server # for server application
 ```

client.cpp

@@ -1,10 +1,46 @@
-#include <iostream>
 #include <opencv2/videoio.hpp>
+#include <cstring>
+#include <iostream>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <packets/ImagePacket.h>
 
 using namespace std;
 
 int main() {
     cv::VideoCapture cap = cv::VideoCapture(0);
-    cout << "Hello World!" << endl;
+
+    int clientSocket = socket(AF_INET, SOCK_STREAM, 0);
+
+    // specifying address
+    sockaddr_in serverAddress;
+    serverAddress.sin_family = AF_INET;
+    serverAddress.sin_port = htons(8080);
+    serverAddress.sin_addr.s_addr = INADDR_ANY;
+
+    cv::Mat image = cv::Mat::zeros(cv::Size(640, 480), CV_8UC3);
+    ImagePacket packet = ImagePacket(&image, 0);
+
+    // sending connection request
+    connect(clientSocket, (struct sockaddr*)&serverAddress,
+            sizeof(serverAddress));
+
+    unsigned long pos = 0;
+    unsigned long len = image.total() * image.elemSize();
+    char buffer[IMAGEPACKET_SIZE];
+
+    cout << "Image length " << len << endl;
+
+    while (true) {
+        cap.read(image);
+        packet = ImagePacket(&image, pos);
+        packet.serialize(buffer);
+        send(clientSocket, buffer, sizeof(buffer), 0);
+        cout << "Sent packet with index " << pos << endl;
+        pos = (pos + SLICE_SIZE) % len;
+    }
+
+    close(clientSocket);
     return 0;
 }

packets/ImagePacket.cpp

@@ -1,38 +1,56 @@
 #include "ImagePacket.h"
 
-/*
- * Construct a packet from an OpenCV Mat, and a beginning index. It will take PACKET_SIZE bytes from the start and add
- * it to its slice
- */
-ImagePacket::ImagePacket(const cv::Mat *image, const int begin) {
-    const uchar *target = &image->data[begin];
-    // TODO: handle out of index cases, pad with zeroes. probably also instantiate our byte array with zeroes
-    for (int i = 0; i < PACKET_SIZE; i++) {
-        slice[i] = target[begin + i];
-    }
-}
-
 /*
  * Construct a packet from a raw array of unsigned chars, and a beginning index. It will take PACKET_SIZE bytes from the
  * start and add it to its slice. This will be more useful for embedded scenarios where OpenCV will likely not be used.
  */
 ImagePacket::ImagePacket(const uchar *image, const int begin) {
+    this->begin = begin;
+    this->slice = new uchar[SLICE_SIZE];
     const uchar *target = &image[begin];
     // TODO: handle out of index cases, pad with zeroes. probably also instantiate our byte array with zeroes
-    for (int i = 0; i < PACKET_SIZE; i++) {
-        slice[i] = target[begin + i];
+    for (int i = 0; i < SLICE_SIZE; i++) {
+        this->slice[i] = target[begin + i];
     }
 }
 
+/*
+ * destructor frees memory
+ */
+ImagePacket::~ImagePacket() = default;
+
+unsigned long ImagePacket::getBegin() const {
+    return this->begin;
+}
+
+
 /*
  * Apply the packet to an OpenCV Mat.
  */
 int ImagePacket::apply(const cv::Mat *image) const {
-    uchar *target = &image->data[begin];
+    uchar *target = &image->data[this->begin];
     // TODO: handle out of index cases
-    for (int i = 0; i < PACKET_SIZE; i++) {
-        target[begin + i] = slice[i];
+    for (int i = 0; i < SLICE_SIZE; i++) {
+        target[this->begin + i] = this->slice[i];
     }
     // TODO: return the actual written size of the packet
-    return PACKET_SIZE;
+    return SLICE_SIZE;
+}
+
+/*
+ * Serialize the object into a byte array
+ */
+void ImagePacket::serialize(char* buffer) const {
+    // TODO: keep the endianness consistent between systems
+    std::memcpy(buffer, &this->begin, sizeof(this->begin));
+    std::memcpy(buffer + sizeof(this->begin), &this->slice, SLICE_SIZE * sizeof(uchar));
+}
+
+/*
+ * Deserialize the object from a byte array
+ */
+void ImagePacket::deserialize(char* buffer) {
+    // TODO: keep the endianness consistent between systems
+    std::memcpy(&this->begin, buffer, sizeof(this->begin));
+    std::memcpy(this->slice, buffer + sizeof(this->begin), SLICE_SIZE * sizeof(uchar));
 }

packets/ImagePacket.h

@@ -2,17 +2,23 @@
 #define IMAGEPACKET_H
 #include <opencv2/core/mat.hpp>
 
-#define PACKET_SIZE 768
+#define SLICE_SIZE 768
+#define IMAGEPACKET_SIZE sizeof(int) + (SLICE_SIZE * sizeof(uchar))
 
 class ImagePacket {
   public:
-    ImagePacket(const cv::Mat *image, int begin);
+    ImagePacket(const cv::Mat *image, int begin) : ImagePacket(image->data, begin) {}
     ImagePacket(const uchar *image, int begin);
+    ~ImagePacket();
+
+    unsigned long getBegin() const;
     int apply(const cv::Mat *image) const;
 
+    void serialize(char* buffer) const;
+    void deserialize(char* buffer);
   private:
-    int begin;
-    uchar slice[PACKET_SIZE];
+    unsigned long begin;
+    uchar *slice;
 };
 
 #endif //IMAGEPACKET_H

server.cpp

@@ -1,20 +1,55 @@
 #include <opencv2/highgui.hpp>
-#include <opencv2/videoio.hpp>
 #include <opencv2/core/mat.hpp>
+#include <cstring>
+#include <iostream>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <packets/ImagePacket.h>
 
 using namespace std;
 
 int main() {
     // TODO: read image data from socket instead of VideoCapture
-    cv::VideoCapture cap = cv::VideoCapture(0);
-    bool running = true;
+    // creating socket
+    int serverSocket = socket(AF_INET, SOCK_STREAM, 0);
+
+    // specifying the address
+    sockaddr_in serverAddress;
+    serverAddress.sin_family = AF_INET;
+    serverAddress.sin_port = htons(8080);
+    serverAddress.sin_addr.s_addr = INADDR_ANY;
+
+    // binding socket.
+    bind(serverSocket, (struct sockaddr*)&serverAddress,
+         sizeof(serverAddress));
+
+    // listening to the assigned socket
+    listen(serverSocket, 5);
+
+    // accepting connection request
+    int clientSocket
+        = accept(serverSocket, nullptr, nullptr);
+
     // TODO: handle multiple images
     cv::Mat image = cv::Mat::zeros(480, 640, CV_8UC3);
+
+    // setup packet buffer
+    char buffer[IMAGEPACKET_SIZE] = { 0 };
+    ImagePacket packet = ImagePacket(&image, 0);
+
+    bool running = true;
     // TODO: make this asynchronous. probably do that in tandem with setting up networking
     while (running) {
-        cap.read(image);
+        // receive data
+        recv(clientSocket, buffer, sizeof(buffer), 0);
+        packet.deserialize(buffer);
+        cout << "received packet with index " << packet.getBegin() << endl;
+        packet.apply(&image);
+
         imshow("image", image);
         running = cv::waitKey(30) != 27;
     }
+    close(serverSocket);
     return 0;
 }