src/marnav/io/seatalk_reader.hpp

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