Files related to my blog post about communicating over BLE using protocol buffers.

Packet.proto

syntax = "proto3";

message Packet {
  float time = 1;
  sint32 rx = 2;
  sint32 ry = 3;
  sint32 rz = 4;
}

ProtobufDecoding.swift

do {
    let packet = try Packet(serializedData: data)
    let date = Date(timeIntervalSinceReferenceDate: Double(packet.time))
    NSLog("[\(formatter.string(from: date))] x: \(packet.rx), y: \(packet.ry), z: \(packet.rz)")
} catch {
    NSLog("Could not parse protobuf data: \(error.localizedDescription)")
}

ProtobufEncoding.swift

var packet = Packet()
if let motionData = self.motionData {
    packet.rx = Int32(motionData.attitude.pitch * rad2Deg)
    packet.ry = Int32(motionData.attitude.yaw * rad2Deg)
    packet.rz = Int32(motionData.attitude.roll * rad2Deg)
}
let now = Date()
packet.time = Float(now.timeIntervalSinceReferenceDate)

guard let data = try? packet.serializedData() else {
    NSLog("Unable to create data from protocol buffer.")
    return
}

// Write the data to the appropriate characteristic.