src/marnav/io/seatalk_reader.hpp

   1 #ifndef __MARNAV__IO__SEATALK_READER__HPP__
   2 #define __MARNAV__IO__SEATALK_READER__HPP__
   3
   4 #include <marnav/io/device.hpp>
   5 #include <marnav/seatalk/message.hpp>
   6
   7 namespace marnav
   8 {
   9 namespace io
  10 {
  11 /// This class reads SeaTalk messages from a device. Normally this would
  12 /// be a serial character device (e.g. /dev/ttyS0 or /dev/ttyUSB0).
  13 ///
  14 /// In order to use this SeaTalk reader, it must be subclassed.
  15 ///
  16 /// @example read_seatalk.cpp
  17 class seatalk_reader
  18 {
  19 public:
  20         virtual ~seatalk_reader();
  21
  22         seatalk_reader() = delete;
  23         seatalk_reader(std::unique_ptr<device> && dev);
  24         seatalk_reader(const seatalk_reader &) = delete;
  25         seatalk_reader(seatalk_reader &&) = default;
  26
  27         seatalk_reader & operator=(const seatalk_reader &) = delete;
  28         seatalk_reader & operator=(seatalk_reader &&) = default;
  29
  30         void close();
  31         bool read();
  32         uint32_t get_collisions() const { return ctx.collisions; }
  33
  34 protected:
  35         virtual void process_message(const seatalk::raw &) = 0;
  36
  37 private:
  38         enum class State { READ, ESCAPE, PARITY };
  39
  40         struct context {
  41                 State state;
  42                 uint8_t index;
  43                 uint8_t remaining;
  44                 uint8_t data[seatalk::MAX_MESSAGE_SIZE];
  45
  46                 uint8_t raw;
  47                 uint32_t collisions;
  48         };
  49
  50         void emit_message();
  51
  52         uint8_t parity(uint8_t a) const;
  53         void write_cmd(uint8_t c);
  54         void write_data(uint8_t c);
  55         void process_seatalk();
  56         bool read_data();
  57
  58         context ctx;
  59         std::unique_ptr<device> dev; ///< Device to read data from.
  60 };
  61 }
  62 }
  63
  64 #endif