serial_pos.cpp

/**
 * @file /src/lib/serial_pos.cpp
 *
 * @brief Posix implementation for serial ports.
 *
 * @date September 2009
 **/

/*****************************************************************************
** Platform Check
*****************************************************************************/

#include <ecl/config/ecl.hpp>
#ifdef ECL_IS_POSIX

/*****************************************************************************
** Includes
*****************************************************************************/

#include <fcntl.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <cstdlib> // div
#include <ecl/exceptions/standard_exception.hpp>
#include <ecl/exceptions/macros.hpp>
#include "../../include/ecl/devices/serial_pos.hpp"
#include "../../include/ecl/devices/detail/error_handler_pos.hpp"

/*****************************************************************************
** Namespaces
*****************************************************************************/

namespace ecl {

/*****************************************************************************
** Using
*****************************************************************************/

using std::string;
using ecl::InvalidInputError;
using ecl::OpenError;
using ecl::StandardException;

/*****************************************************************************
** Implementation [Serial][C&D]
*****************************************************************************/

Serial::Serial(const std::string& port_name, const BaudRate &baud_rate, const DataBits &data_bits,
		const StopBits &stop_bits, const Parity &parity ) ecl_throw_decl(StandardException) :
				port(port_name),
				read_timeout_ms(5000),
				error_handler(NoError)
{
	ecl_try {
		open(port_name, baud_rate, data_bits, stop_bits, parity);
	} ecl_catch( const StandardException &e ) {
		ecl_throw(StandardException(LOC,e));
	}
}

Serial::~Serial() {
	close();
}

/*****************************************************************************
** Implementation [Serial][Open]
*****************************************************************************/

bool Serial::open(const std::string& port_name, const BaudRate &baud_rate, const DataBits &data_bits,
		const StopBits &stop_bits, const Parity &parity ) ecl_throw_decl(StandardException) {

	/*********************
	** Input Checks
	**********************/
	if ( stop_bits == StopBits_15 ) {
		ecl_throw(StandardException(LOC,ConfigurationError,"Standard serial device does not accept StopBits_15 as valid (used in ftdi)."));
		error_handler = InvalidArgError;
    	is_open = false;
		return false;
	}

	if ( open() ) {
		close();
	}
	port = port_name;
	// One curious thing here is O_NONBLOCK. If you do not specify this, it will try
	// and wait till the line has an 'other' end. Which it can't possibly know, so
	// it will effectively block here forever.
    file_descriptor = ::open( port_name.c_str(), O_RDWR | O_NOCTTY | O_NONBLOCK );
    if ( file_descriptor == -1 ) {
        ecl_throw(devices::open_exception(LOC,port_name));
        error_handler = devices::open_error();
    	is_open = false;
        return false;
    }

    static const int baud_rate_flags[] = { B110, B300, B600, B1200, B2400, B4800, B9600, B19200, B38400, B57600, B115200, B921600 };
    static const int data_bits_flags[] = { CS5, CS6, CS7, CS8 };

    /*********************
    ** Current Settings
    **********************/
//    tcgetattr(file_descriptor,&options); // Need?

    /******************************************
    ** Flow Control
    *******************************************/
    // Turn off the O_NONBLOCK we set back when opening (we want by default
    // blocking and timeouts etc to occur).
    // Using 0 as the argument here resets the file status flags to defaults.
    fcntl(file_descriptor, F_SETFL, 0);
    // this came from ros' hokoyu node code for setting a lock on the device file descriptor
    // useful if you want to make sure other devices dont mess with your device!
    struct flock file_lock;
    file_lock.l_type = F_WRLCK;
    file_lock.l_whence = SEEK_SET;
    file_lock.l_start = 0;
    file_lock.l_len   = 0;
    file_lock.l_pid   = getpid();
    if (fcntl(file_descriptor, F_SETLK, &file_lock) != 0) {
    	ecl_throw_decl(StandardException(LOC,OpenError,std::string("Device is already locked. Try 'lsof | grep ") + port + std::string("' to find other processes that currently have the port open.")));
    	error_handler = IsLockedError;
    	is_open = false;
    	return false;
    }

    /******************************************
    ** Initialise flags
    *******************************************/
    options.c_cflag = 0;
    options.c_iflag = 0;
    options.c_lflag = 0;
    options.c_oflag = 0;

    /*********************
    ** Baud rates
    **********************/
    cfsetispeed(&options, baud_rate_flags[baud_rate]);

    /*********************
    ** Ownership
    **********************/
    /*
     * CLOCAL and CREAD should always be set.
     * They make sure the owner of the port is
     * not changed by the program.
     */
    options.c_cflag |= CLOCAL;
    options.c_cflag |= CREAD;

    /*********************
    ** Disable Flow control
    **********************/
    #if defined(CRTSCTS)
         options.c_cflag &= ~CRTSCTS;    // Disable hardware flow control (old)
    #elif defined (CNEW_RTSCTS)
         options.c_cflag &= ~CNEW_RTSCTS;    // Disable hardware flow control (new)
    #endif

    /*********************
    ** StopBits
    **********************/
     if ( stop_bits == StopBits_1 ) {
         options.c_cflag &= ~CSTOPB;     // One stop bit only
     } else {
         options.c_cflag |= CSTOPB;      // Two stop bits.
     }

     /******************************************
     ** DataBits
     *******************************************/
     options.c_cflag &= ~CSIZE;         // Mask (i.e. reset) character size bits
     options.c_cflag |= data_bits_flags[data_bits]; // Now set the # data bits

    /******************************************
    ** Processing
    *******************************************/
    options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); // raw, no echoing or waiting till a flush or signals
    // options.c_lflag |= (ICANON | ECHO | ECHOE); // like a chat session

    /******************************************
    ** Input Options
    *******************************************/
    options.c_iflag &= ~(IXON | IXOFF | IXANY); // Disable software flow control

    /******************************************
    ** Output Options
    *******************************************/
//    options.c_oflag |= OPOST; // Perform a little post processing
//    options.c_oflag |= ONLCR; // Man NL to NL-CR

    /*********************
     ** Parity
     **********************/
     if ( parity == NoParity ) {
         options.c_cflag &= ~PARENB;     // No Parity
     } else if ( parity == EvenParity ) {
         options.c_iflag |= (INPCK | ISTRIP); // Enable parity check and strip parity bit
         options.c_cflag |= PARENB;
         options.c_cflag &= ~PARODD;
     } else { // OddParity
         options.c_iflag |= (INPCK | ISTRIP); // Enable parity check and strip parity bit
         options.c_cflag |= PARENB;
         options.c_cflag |= PARODD;
     }

    /******************************************
    ** Enable
    *******************************************
    * TCSANOW - make changes immediately
    * TCSADRAIN - wait till everything is transmitted
    * TCSAFLUSH - clear input/output buffers and change
    *******************************************/
    tcsetattr(file_descriptor,TCSAFLUSH,&options);

    block(5000);

    is_open = true;
    error_handler = NoError;
    return true;
}
void Serial::close() {
	if ( open() ) {
		// should check return values here, it does have some, EBADF/EINTR/EIO
		::close(file_descriptor);
	    is_open = false;
	}
}

/*****************************************************************************
** Implementation [Serial][Reading Modes]
*****************************************************************************/

void Serial::block(const unsigned long &timeout) {
	if ( timeout < 100 ) {
		if ( timeout < 5 ) {
			fake_snooze.period(ecl::Duration(0.001));
			fake_loop_count = timeout;
		} else if ( timeout < 20 ) {
			fake_snooze.period(ecl::Duration(0.002));
			div_t d = div(timeout,2);
			if ( d.rem == 0 ) {
				fake_loop_count = d.quot;
			} else {
				fake_loop_count = d.quot + 1;
			}
		} else {
			fake_snooze.period(ecl::Duration(0.005));
			div_t d = div(timeout,5);
			if ( d.rem == 0 ) {
				fake_loop_count = d.quot;
			} else {
				fake_loop_count = d.quot + 1;
			}
		}
		this->unblock();
	} else {
		options.c_cc[VMIN] = 0;
		 // VTIME is in tenths of a second
		if ( timeout < 100 ) { // just in case we're not running in debug mode or exceptions are disabled.
			options.c_cc[VTIME] = static_cast<unsigned char>(1); // 100/100
		} else {
			options.c_cc[VTIME] = static_cast<unsigned char>(timeout/100);
		}
		tcsetattr(file_descriptor, TCSAFLUSH, &options);
	}
	read_timeout_ms = timeout;
}

void Serial::unblock() {
    options.c_cc[VMIN] = 0;
    options.c_cc[VTIME] = 0;
    tcsetattr(file_descriptor, TCSAFLUSH, &options);
	read_timeout_ms = 5000; // just so we don't trigger fake_read calls in read(xxx)
}

/*****************************************************************************
** Implementation [Serial][Reading]
*****************************************************************************/
long Serial::remaining() {
    long bytes = 0;
    ioctl(file_descriptor, FIONREAD, &bytes);
    return bytes;
}

} // namespace ecl
#endif /* ECL_IS_POSIX */