DDS, SOME/IP, gRPC Comparison

// SOME/IP speed event provider using vsomeip library
#include <vsomeip/vsomeip.hpp>
#include <thread>

static const vsomeip::service_t SERVICE_ID = 0x0A01;
static const vsomeip::instance_t INSTANCE_ID = 0x0001;
static const vsomeip::event_t    SPEED_EVENT_ID = 0x0001;
static const vsomeip::eventgroup_t EVENTGROUP_ID = 0x0001;

class SpeedProvider {
public:
    SpeedProvider() {
        app_ = vsomeip::runtime::get()->create_application("SpeedProvider");
    }

    void init() {
        app_->init();
        app_->offer_service(SERVICE_ID, INSTANCE_ID);
        app_->offer_event(
            SERVICE_ID, INSTANCE_ID,
            SPEED_EVENT_ID,
            {EVENTGROUP_ID},
            vsomeip::event_type_e::ET_FIELD);
    }

    void publish_speed(float speed_kmh) {
        auto payload = vsomeip::runtime::get()->create_payload();
        // Serialise float to 4 bytes (big-endian / SOME/IP network order)
        uint32_t raw;
        std::memcpy(&raw, &speed_kmh, sizeof(float));
        std::vector<vsomeip::byte_t> data(4);
        data[0] = (raw >> 24) & 0xFF;
        data[1] = (raw >> 16) & 0xFF;
        data[2] = (raw >>  8) & 0xFF;
        data[3] =  raw        & 0xFF;
        payload->set_data(data);
        app_->notify(SERVICE_ID, INSTANCE_ID, SPEED_EVENT_ID, payload);
    }

    void run() { app_->start(); }

private:
    std::shared_ptr<vsomeip::application> app_;
};

int main() {
    SpeedProvider provider;
    provider.init();
    // Simulate 100 Hz speed updates
    std::thread([&] {
        float speed = 0.0f;
        while (true) {
            provider.publish_speed(speed);
            speed = (speed < 120.0f) ? speed + 0.1f : 0.0f;
            std::this_thread::sleep_for(std::chrono::milliseconds(10));
        }
    }).detach();
    provider.run();
}