SerialCommPort.h

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//-*-c++-*-
#ifndef INCLUDED_SerialCommPort_h_
#define INCLUDED_SerialCommPort_h_

#include "FileSystemCommPort.h"
#include <fcntl.h>
#include <termios.h>

//! Provides CommPort interface to serial port devices -- essentially just a FileSystemCommPort, but can apply terminal IO settings
/*! You could use FileSystemCommPort instead of this class, and thus
 *  rely on a prior manual call to stty.  However, other programs (or rebooting)
 *  will reset those parameters, so it's nice to use this class to ensure the
 *  desired settings are reapplied each time the device is opened. */
class SerialCommPort : public FileSystemCommPort {
public:
  //! constructor
  explicit SerialCommPort(const std::string& name)
  : FileSystemCommPort(autoRegisterSerialCommPort,name),
  baudRate(57600), dataBits(8), stopBits(1), parity(NONE,parityNames), sttyConfig(),
  fd(-1)
  {
    if(bauds.size()==0)
      initBauds();
    addEntry("Baud",baudRate,"Communication frequency (bits per second)");
    addEntry("DataBits",dataBits,"Number of data bits to send at a time (5-8)");
    addEntry("StopBits",stopBits,"Number of stop bits to send between data bits (1-2)");
    addEntry("Parity",parity,"Parity bit can be sent for error checking\n"+parity.getDescription());
    addEntry("TTYFlags",sttyConfig,"Additional configuration string to pass to stty\n(may not work when using non-standard baud rates on OS X)");
    baudRate.addPrimitiveListener(this);
    dataBits.addPrimitiveListener(this);
    stopBits.addPrimitiveListener(this);
    parity.addPrimitiveListener(this);
    sttyConfig.addPrimitiveListener(this);
  }
  
  //! destructor
  ~SerialCommPort() {
    baudRate.removePrimitiveListener(this);
    dataBits.removePrimitiveListener(this);
    stopBits.removePrimitiveListener(this);
    parity.removePrimitiveListener(this);
    sttyConfig.removePrimitiveListener(this);
  }

  virtual std::string getClassName() const { return autoRegisterSerialCommPort; }
  
  virtual bool open() {
    if(openedCnt==0) { // just do it on initial call
      // open serial port, need to keep it open through the FileSystemCommPort opening
      fd = ::open(path.c_str(), O_RDWR | O_NONBLOCK);
      setupSerial();
    }
    return FileSystemCommPort::open();
  }
  
  virtual bool close() {
    bool ans = FileSystemCommPort::close();
    if(openedCnt==0) {
			::close(fd);
      fd=-1;
    }
    return ans;
  }
  
  //! watches #sttyConfig, reapplies the settings if changed
  virtual void plistValueChanged(const plist::PrimitiveBase& pl) {
    if(&pl==&sttyConfig) {
      setupSerial();
    } else if(&pl==&baudRate) {
      setupSerial();
    } else if(&pl==&dataBits) {
      if(dataBits<5 || dataBits>8) {
        std::cerr << "Cannot set DataBits to " << dataBits << ", reset to " << dataBits.getPreviousValue() << std::endl;
        dataBits=dataBits.getPreviousValue();
        return;
      }
      setupSerial();
    } else if(&pl==&stopBits) {
      if(stopBits<1 || stopBits>2) {
        std::cerr << "Cannot set StopBits to " << stopBits << ", reset to " << stopBits.getPreviousValue() << std::endl;
        stopBits=stopBits.getPreviousValue();
        return;
      }
      setupSerial();
    } else if(&pl==&parity) {
      setupSerial();
    } else {
      // path or mode changed... if opened, will be called if changing path...
      FileSystemCommPort::plistValueChanged(pl);
    }
  }
  
  plist::Primitive<unsigned int> baudRate;
  plist::Primitive<unsigned int> dataBits;
  plist::Primitive<unsigned int> stopBits;
  enum parity_t { EVEN, ODD, NONE };
  static const char * const parityNames[];
  plist::NamedEnumeration<parity_t> parity;
  plist::Primitive<std::string> sttyConfig; //!< Configuration string to pass to stty
  
protected:
  //! file descriptor for serial port -- needed for tcsetattr and ioctl interfaces
  int fd;
  
  //! performs serial port initialization (if fd is non-negative)
  virtual void setupSerial();
  
  void dispError(const char* where, int ret, int err);

  //! initializes #bauds with all of the symbolic baud rate settings available on host platform
  static void initBauds();

  //! table of valid baud rates
  static std::map<int,speed_t> bauds;
    
  //! holds the class name, set via registration with the CommPort registry
  static const std::string autoRegisterSerialCommPort;
};

/*! @file
* @brief Describes SerialCommPort, which provides CommPort interface to serial port devices -- essentially just a FileSystemCommPort, but can apply terminal IO settings
* @author Ethan Tira-Thompson (ejt) (Creator)
*/

#endif