pkg=event_camera_codecs
mkdir -p ~/$pkg/src
cd ~/ws
git clone https://github.com/ros-event-camera/${pkg}.git src/${pkg}
cd src
vcs import < ${pkg}/${pkg}.repos
cd ..

catkin config -DCMAKE_BUILD_TYPE=RelWithDebInfo  # (optionally add -DCMAKE_EXPORT_COMPILE_COMMANDS=1)
catkin build

cd ~/ws
colcon build --symlink-install --cmake-args -DCMAKE_BUILD_TYPE=RelWithDebInfo  # (optionally add -DCMAKE_EXPORT_COMPILE_COMMANDS=1)

#include <event_camera_codecs/decoder.h>
#include <event_camera_codecs/decoder_factory.h>

using event_camera_codecs::EventPacket;

class MyProcessor : public event_camera_codecs::EventProcessor
{
public:
  inline void eventCD(uint64_t, uint16_t ex, uint16_t ey, uint8_t polarity) override {
    // do useful stuff here
  }
  void eventExtTrigger(uint64_t, uint8_t, uint8_t) override {}
  void finished() override{}; // called after no more events decoded in this packet
  void rawData(const char *, size_t) override{};  // passthrough of raw data
};

MyProcessor processor;

// the decoder factory method is templated on the event processor
// to permit inlining of methods like eventCD() above.

event_camera_codecs::DecoderFactory<EventPacket, MyProcessor> decoderFactory;

// to get callbacks into MyProcessor, feed the message buffer
// into the decoder like so

void eventMsg(const event_camera_codecs::EventPacketConstSharedPtr & msg) {
  // will create a new decoder on first call, from then on returns existing one
  auto decoder = decoderFactory.getInstance(*msg);
  if (!decoder) { // msg->encoding was invalid
    return;
  }
  // the decode() will trigger callbacks to processor
  decoder->decode(*msg, &processor);
}

/* To synchronize with frame based sensors it is useful to play back
   until a frame boundary is reached. The interface decodeUntil() is provided
   for this purpose. In the sample code below.
   frameTimes is an ordered queue of frame times.
   */

void eventMsg2(const event_camera_codecs::EventPacketConstSharedPtr & msg) {
  auto decoder = decoderFactory.getInstance(*msg);
  uint64_t nextTime{0};
  // The loop will exit when all events in msg have been processed
  // or there are no more frame times available
  while (!frameTimes.empty() &&
    decoder->decodeUntil(*msg, &processor, frameTimes.front(), &nextTime)) {
    // use loop in case multiple frames fit inbetween two events
    while (!frameTimes.empty() && frameTimes.front() <= nextTime) {
      // processFrameHere()
      frameTimes.pop();
    }
  }
}

# decode a raw file and measure performance
rosrun event_camera_codecs codec_perf -i foo.raw

# decode a raw file and measure performance
ros2 run event_camera_codecs codec_perf -i foo.raw

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