uint64_t
hokuyo::Laser::readTime(int timeout)
{
  char buf[100];

  laserReadline(buf, 100, timeout);
  if (!checkSum(buf, 6))
    HOKUYO_EXCEPT(hokuyo::CorruptedDataException, "Checksum failed on time stamp.");

  unsigned int laser_time = ((buf[0]-0x30) << 18) | ((buf[1]-0x30) << 12) | ((buf[2]-0x30) << 6) | (buf[3] - 0x30);

  if (laser_time == last_time_)
  {
    if (++time_repeat_count_ > 2)
    {
      HOKUYO_EXCEPT(hokuyo::RepeatedTimeException, "The timestamp has not changed for %d reads", time_repeat_count_);
    }
    else if (time_repeat_count_ > 0)
      ROS_DEBUG("The timestamp has not changed for %d reads. Ignoring for now.", time_repeat_count_);
  }
  else
  {
    time_repeat_count_ = 0;
  }

  if (laser_time < last_time_)
    wrapped_++;
  
  last_time_ = laser_time;
  
  return (uint64_t)((wrapped_ << 24) | laser_time)*(uint64_t)(1000000);
}

void
hokuyo::Laser::queryVersionInformation()
{
    if (!portOpen())
        HOKUYO_EXCEPT(hokuyo::Exception, "Port not open.");

    if (sendCmd("VV",1000) != 0)
        HOKUYO_EXCEPT(hokuyo::Exception, "Error requesting version information");

    char buf[100];
    vendor_name_ = laserReadlineAfter(buf, 100, "VEND:");
    vendor_name_ = vendor_name_.substr(0,vendor_name_.length() - 3);

    product_name_ = laserReadlineAfter(buf, 100, "PROD:");
    product_name_ = product_name_.substr(0,product_name_.length() - 3);

    firmware_version_ = laserReadlineAfter(buf, 100, "FIRM:");
    firmware_version_ = firmware_version_.substr(0,firmware_version_.length() - 3);

    protocol_version_ = laserReadlineAfter(buf, 100, "PROT:");
    protocol_version_ = protocol_version_.substr(0,protocol_version_.length() - 3);

    // This crazy naming scheme is for backward compatibility. Initially
    // the serial number always started with an H. Then it got changed to a
    // zero. For a while the driver was removing the leading zero in the
    // serial number. This is fine as long as it is indeed a zero in front.
    // The current behavior is backward compatible but will accomodate full
    // length serial numbers.
    serial_number_ = laserReadlineAfter(buf, 100, "SERI:");
    serial_number_ = serial_number_.substr(0,serial_number_.length() - 3);
    if (serial_number_[0] == '0')
        serial_number_[0] = 'H';
    else if (serial_number_[0] != 'H')
        serial_number_ = 'H' + serial_number_;
}

int
hokuyo::Laser::sendCmd(const char* cmd, int timeout)
{
if (!portOpen())
    HOKUYO_EXCEPT(hokuyo::Exception, "Port not open.");

  char buf[100]; 
  //printf("sendreq: %s\n", cmd);
  laserWrite(cmd);
  laserWrite("\n");;
  laserReadlineAfter(buf, 100, cmd, timeout);
  laserReadline(buf,100,timeout);
  //printf("chksum: %s",buf);
  if (!checkSum(buf,4))
  {
    //printf("chksum error\n");
    HOKUYO_EXCEPT(hokuyo::CorruptedDataException, "Checksum failed on status code.");
  }
  buf[2] = 0;
  //printf("sendreq_end: %s\n", cmd);

  if (buf[0] - '0' >= 0 && buf[0] - '0' <= 9 && buf[1] - '0' >= 0 && buf[1] - '0' <= 9)
    return (buf[0] - '0')*10 + (buf[1] - '0');
  else
    HOKUYO_EXCEPT(hokuyo::Exception, "Hokuyo error code returned. Cmd: %s --  Error: %s", cmd, buf);
}

void
hokuyo::Laser::querySensorConfig()
{
  if (!portOpen())
    HOKUYO_EXCEPT(hokuyo::Exception, "Port not open.");

  if (sendCmd("PP",1000) != 0)
    HOKUYO_EXCEPT(hokuyo::Exception, "Error requesting configuration information");

  char buf[100];
  char* ind;
    
  ind = laserReadlineAfter(buf,100,"DMIN:",-1);
  sscanf(ind, "%d", &dmin_);
    
  ind = laserReadlineAfter(buf,100,"DMAX:",-1);
  sscanf(ind, "%d", &dmax_);
    
  ind = laserReadlineAfter(buf,100,"ARES:",-1);
  sscanf(ind, "%d", &ares_);
    
  ind = laserReadlineAfter(buf,100,"AMIN:",-1);
  sscanf(ind, "%d", &amin_);
    
  ind = laserReadlineAfter(buf,100,"AMAX:",-1);
  sscanf(ind, "%d", &amax_);
    
  ind = laserReadlineAfter(buf,100,"AFRT:",-1);
  sscanf(ind, "%d", &afrt_);
    
  ind = laserReadlineAfter(buf,100,"SCAN:",-1);
  sscanf(ind, "%d", &rate_);
    
  return;
}

void
hokuyo::Laser::readData(hokuyo::LaserScan& scan, bool has_intensity, int timeout)
{
  scan.ranges.clear();
  scan.intensities.clear();

  int data_size = 3;
  if (has_intensity)
    data_size = 6;

  char buf[100];

  int ind = 0;

  scan.self_time_stamp = readTime(timeout);

  int bytes;

  float range;
  float intensity;

  for (;;)
  {
    bytes = laserReadline(&buf[ind], 100 - ind, timeout);
    
    if (bytes == 1)          // This is \n\n so we should be done
      return;
    
    if (!checkSum(&buf[ind], bytes))
      HOKUYO_EXCEPT(hokuyo::CorruptedDataException, "Checksum failed on data read.");
    
    bytes += ind - 2;
    
    // Read as many ranges as we can get
    for (int j = 0; j < bytes - (bytes % data_size); j+=data_size)
    {
      if (scan.ranges.size() < MAX_READINGS)
      {
        range = (((buf[j]-0x30) << 12) | ((buf[j+1]-0x30) << 6) | (buf[j+2]-0x30)) / 1000.0;
	scan.ranges.push_back(range);

        if (has_intensity)
        {
	  intensity = (((buf[j+3]-0x30) << 12) | ((buf[j+4]-0x30) << 6) | (buf[j+5]-0x30));
          scan.intensities.push_back(intensity);
        }
      }
      else
      {
        HOKUYO_EXCEPT(hokuyo::CorruptedDataException, "Got more readings than expected");
      }
    }
    // Shuffle remaining bytes to front of buffer to get them on the next loop
    ind = 0;
    for (int j = bytes - (bytes % data_size); j < bytes ; j++)
      buf[ind++] = buf[j];
  }
}

int
hokuyo::Laser::laserReadline(char *buf, int len, int timeout)
{
    int current=0;

    struct pollfd ufd[1];
    int retval;
    ufd[0].fd = laser_fd_;
    ufd[0].events = POLLIN;

    if (timeout == 0)
        timeout = -1; // For compatibility with former behavior, 0 means no timeout. For poll, negative means no timeout.

    while (true)
    {
        if (read_buf_start == read_buf_end) // Need to read?
        {
            if ((retval = poll(ufd, 1, timeout)) < 0)
                HOKUYO_EXCEPT(hokuyo::Exception, "poll failed   --  error = %d: %s", errno, strerror(errno));

            if (retval == 0)
                HOKUYO_EXCEPT(hokuyo::TimeoutException, "timeout reached");

            if (ufd[0].revents & POLLERR)
                HOKUYO_EXCEPT(hokuyo::Exception, "error on socket, possibly unplugged");

            int bytes = read(laser_fd_, read_buf, sizeof(read_buf));
            if (bytes == -1 && errno != EAGAIN && errno != EWOULDBLOCK)
                HOKUYO_EXCEPT(hokuyo::Exception, "read failed");
            read_buf_start = 0;
            read_buf_end = bytes;
        }

        while (read_buf_end != read_buf_start)
        {
            if (current == len - 1)
            {
                buf[current] = 0;
                HOKUYO_EXCEPT(hokuyo::Exception, "buffer filled without end of line being found");
            }

            buf[current] = read_buf[read_buf_start++];
            if (buf[current++] == '\n')
            {
                buf[current] = 0;
                return current;
            }
        }

#ifdef USE_LOG_FILE
        long long outtime = timeHelper();
        fprintf(logfile, "In: %lli.%09lli %s", outtime / 1000000000L, outtime % 1000000000L, buf);
#endif
    }
}

bool
hokuyo::Laser::isIntensitySupported()
{
  hokuyo::LaserScan  scan;
  
  if (!portOpen())
    HOKUYO_EXCEPT(hokuyo::Exception, "Port not open.");

  // Try an intensity command.
  try
  {
    requestScans(1, 0, 0, 0, 0, 1);
    serviceScan(scan, 1000);
    return true;
  }
  catch (hokuyo::Exception &e)
  {} 
  
  // Try an intensity command.
  try
  {
    requestScans(0, 0, 0, 0, 0, 1);
    serviceScan(scan, 1000);
    return false;
  }
  catch (hokuyo::Exception &e)
  {
    HOKUYO_EXCEPT(hokuyo::Exception, "Exception whil trying to determine if intensity scans are supported.")
  } 
}

void
hokuyo::Laser::close ()
{
  int retval = 0;

  if (portOpen()) {
    //Try to be a good citizen and completely shut down the laser before we shutdown communication
    try
    {
      reset();
    }
    catch (hokuyo::Exception& e) {
      //Exceptions here can be safely ignored since we are closing the port anyways
    }
#if HOKUYO_INTERFACE_ETHERNET
    tcpclient_close(&tcpclient);
#else
    retval = ::close(laser_fd_); // Automatically releases the lock.
#endif

  }

  laser_fd_ = -1;

  if (retval != 0)
    HOKUYO_EXCEPT(hokuyo::Exception, "Failed to close port properly -- error = %d: %s\n", errno, strerror(errno));
}

int
hokuyo::Laser::laserOn() {
  int res = sendCmd("BM",1000);
  if (res == 1)
    HOKUYO_EXCEPT(hokuyo::Exception, "Unable to control laser due to malfunction.");
  return res;
}

long long int hokuyo::Laser::getHokuyoScanStampToSystemStampOffset(bool intensity, double min_ang, double max_ang, int clustering, int skip, int reps, int timeout)
{
    if (reps < 1)
        reps = 1;
    else if (reps > 99)
        reps = 99;

    std::vector<long long int> offset(reps);

    if (requestScans(intensity, min_ang, max_ang, clustering, skip, reps, timeout) != 0)
    {
        HOKUYO_EXCEPT(hokuyo::Exception, "Error requesting scan while caliblating time.");
        return 1;
    }

    hokuyo::LaserScan scan;
    for (int i = 0; i < reps; i++)
    {
        serviceScan(scan, timeout);
        //printf("%lli %lli\n", scan.self_time_stamp, scan.system_time_stamp);
        offset[i] = scan.self_time_stamp - scan.system_time_stamp;
    }

    return median(offset);
}

int
hokuyo::Laser::laserWrite(const char* msg)
{
    // IO is currently non-blocking. This is what we want for the more common read case.
    int origflags = fcntl(laser_fd_,F_GETFL,0);
    fcntl(laser_fd_, F_SETFL, origflags & ~O_NONBLOCK); // @todo can we make this all work in non-blocking?
    ssize_t len = strlen(msg);
    ssize_t retval = write(laser_fd_, msg, len);
    int fputserrno = errno;
    fcntl(laser_fd_, F_SETFL, origflags | O_NONBLOCK);
    errno = fputserrno; // Don't want to see the fcntl errno below.

    if (retval != -1)
    {
#ifdef USE_LOG_FILE
        if (strlen(msg) > 1)
        {
            long long outtime = timeHelper();
            fprintf(logfile, "Out: %lli.%09lli %s\n", outtime / 1000000000L, outtime % 1000000000L, msg);
        }
#endif
        return retval;
    }
    else
        HOKUYO_EXCEPT(hokuyo::Exception, "fputs failed -- Error = %d: %s", errno, strerror(errno));
}

void
hokuyo::Laser::open(const char * tcphost, const int tcpport)
{
  if (portOpen())
    close();

  // Make IO non blocking. This way there are no race conditions that
  // cause blocking when a badly behaving process does a read at the same
  // time as us. Will need to switch to blocking for writes or errors
  // occur just after a replug event.

  laser_fd_ = tcpclient_open(&tcpclient,tcphost, tcpport);//::open(port_name, O_RDWR | O_NONBLOCK | O_NOCTTY);
  //laser_fd_ = tcpclient_open(&tcpclient,"127.0.0.1", 10001);//::open(port_name, O_RDWR | O_NONBLOCK | O_NOCTTY);

  read_buf_start = read_buf_end = 0;


  if (laser_fd_ < 0)
  {
    HOKUYO_EXCEPT(hokuyo::Exception, "Failed to open tcp_client: %s:%d. %s (errno = %d)", tcphost,tcpport, strerror(errno), errno);
  }

  laser_fd_ = tcpclient.sock_desc;

  try
  {
    // Some models (04LX) need to be told to go into SCIP2 mode...
    laserFlush();
    // Just in case a previous failure mode has left our Hokuyo
    // spewing data, we send reset the laser to be safe.
    try {
      reset();
    }
    catch (hokuyo::Exception &e)
    {
      // This might be a device that needs to be explicitely placed in
      // SCIP2 mode.
      // Note: Not tested: a device that is currently scanning in SCIP1.1
      // mode might not manage to switch to SCIP2.0.
      setToSCIP2(); // If this fails then it wasn't a device that could be switched to SCIP2.
      reset(); // If this one fails, it really is an error.
    }

    querySensorConfig();

    queryVersionInformation(); // In preparation for calls to get various parts of the version info.
  }
  catch (hokuyo::Exception& e)
  {
    // These exceptions mean something failed on open and we should close
    if (laser_fd_ != -1)
      tcpclient_close(&tcpclient);
    laser_fd_ = -1;
    throw e;
  }

}

int
hokuyo::Laser::laserFlush()
{
  int retval = tcflush(laser_fd_, TCIOFLUSH);
  if (retval != 0)
    HOKUYO_EXCEPT(hokuyo::Exception, "tcflush failed");
  
  return retval;
} 

int 
hokuyo::Laser::laserReadline(char *buf, int len, int timeout)
{
  char* ret;
  int current=0;

  struct pollfd ufd[1];
  int retval;
  ufd[0].fd = laser_fd_;
  ufd[0].events = POLLIN;

  while (current < len - 1)
  {
    if (current > 0)
      if (buf[current-1] == '\n')
	return current;

    if (timeout == 0)
      timeout = -1; // For compatibility with former behavior, 0 means no timeout. For poll, negative means no timeout.

    if ((retval = poll(ufd, 1, timeout)) < 0)
      HOKUYO_EXCEPT(hokuyo::Exception, "poll failed   --  error = %d: %s", errno, strerror(errno));

    if (retval == 0)
      HOKUYO_EXCEPT(hokuyo::TimeoutException, "timeout reached");

    // Non blocking call so we don't block if a misbehaved process is
    // accessing the port.
    ret = fgets(&buf[current], len-current, laser_port_);

    if (ret != &buf[current])
      HOKUYO_EXCEPT(hokuyo::Exception, "fgets failed");

    current += strlen(&buf[current]);
  }
  HOKUYO_EXCEPT(hokuyo::Exception, "buffer filled without end of line being found");
}

int
hokuyo::Laser::laserWrite(const char* msg)
{
  // IO is currently non-blocking. This is what we want for the more common read case.
  int origflags = fcntl(laser_fd_,F_GETFL,0);
  fcntl(laser_fd_, F_SETFL, origflags & ~O_NONBLOCK); // @todo can we make this all work in non-blocking?
  int retval = fputs(msg, laser_port_);
  int fputserrno = errno;
  fcntl(laser_fd_, F_SETFL, origflags | O_NONBLOCK);
  errno = fputserrno; // Don't want to see the fcntl errno below.
  
  if (retval != EOF)
    return retval;
  else
    HOKUYO_EXCEPT(hokuyo::Exception, "fputs failed -- Error = %d: %s", errno, strerror(errno));
}

int
hokuyo::Laser::laserFlush()
{
#if HOKUYO_INTERFACE_ETHERNET
  ::tcpclient_buffer_flush(&tcpclient);
  return 0;
#else
  int retval = tcflush(laser_fd_, TCIOFLUSH);
  if (retval != 0)
    HOKUYO_EXCEPT(hokuyo::Exception, "tcflush failed errno: %d, socfd: %d", errno,laser_fd_);
  read_buf_start = 0;
  read_buf_end = 0;

  return retval;
 #endif

} 

long long
hokuyo::Laser::calcLatency(bool intensity, double min_ang, double max_ang, int clustering, int skip, int num, int timeout)
{
  ROS_DEBUG("Entering calcLatency.");

  if (!portOpen())
    HOKUYO_EXCEPT(hokuyo::Exception, "Port not open.");

  static const std::string buggy_version = "1.16.02(19/Jan./2010)";
  if (firmware_version_ == buggy_version)
  {
    ROS_INFO("Hokuyo firmware version %s detected. Using hard-coded time offset of -23 ms.", 
        buggy_version.c_str());
    offset_ = -23000000;
  }
  else
  {
    offset_ = 0;

    uint64_t comp_time = 0;
    uint64_t laser_time = 0;
    long long diff_time = 0;
    long long drift_time = 0;
    long long tmp_offset1 = 0;
    long long tmp_offset2 = 0;

    int count = 0;

    sendCmd("TM0",timeout);
    count = 100;

    for (int i = 0; i < count;i++)
    {
      usleep(1000);
      sendCmd("TM1",timeout);
      comp_time = timeHelper();
      try 
      {
        laser_time = readTime();

        diff_time = comp_time - laser_time;

        tmp_offset1 += diff_time / count;
      } catch (hokuyo::RepeatedTimeException &e)
      {
        // We expect to get Repeated Time's when hammering on the time server
        continue;
      }
    }

    uint64_t start_time = timeHelper();
    usleep(5000000);
    sendCmd("TM1;a",timeout);
    sendCmd("TM1;b",timeout);
    comp_time = timeHelper();
    drift_time = comp_time - start_time;
    laser_time = readTime() + tmp_offset1;
    diff_time = comp_time - laser_time;
    double drift_rate = double(diff_time) / double(drift_time);

    sendCmd("TM2",timeout);

    if (requestScans(intensity, min_ang, max_ang, clustering, skip, num, timeout) != 0)
      HOKUYO_EXCEPT(hokuyo::Exception, "Error requesting scans during latency calculation");

    hokuyo::LaserScan scan;

    count = 200;
    for (int i = 0; i < count;i++)
    {
      try
      {
        serviceScan(scan, 1000);
      } catch (hokuyo::CorruptedDataException &e) {
        continue;
      }

      comp_time = scan.system_time_stamp;
      drift_time = comp_time - start_time;
      laser_time = scan.self_time_stamp + tmp_offset1 + (long long)(drift_time*drift_rate);
      diff_time = laser_time - comp_time;

      tmp_offset2 += diff_time / count;
    }

    offset_ = tmp_offset2;

    stopScanning();
  }

  ROS_DEBUG("Leaving calcLatency.");

  return offset_;
}

void
hokuyo::Laser::open(const char * port_name)
{
  if (portOpen())
    close();
  
  laser_port_ = fopen(port_name, "r+");
  if (laser_port_ == NULL)
  {
    const char *extra_msg = "";
    switch (errno)
    {
      case EACCES:
        extra_msg = "You probably don't have premission to open the port for reading and writing.";
        break;
      case ENOENT:
        extra_msg = "The requested port does not exist. Is the hokuyo connected? Was the port name misspelled?";
        break;
    }

    HOKUYO_EXCEPT(hokuyo::Exception, "Failed to open port: %s. %s (errno = %d). %s", port_name, strerror(errno), errno, extra_msg);
  }
  try
  {
    laser_fd_ = fileno (laser_port_);
    if (laser_fd_ == -1)
      HOKUYO_EXCEPT(hokuyo::Exception, "Failed to get file descriptor --  error = %d: %s", errno, strerror(errno));

    // Make IO non blocking. This way there are no race conditions that
    // cause blocking when a badly behaving process does a read at the same
    // time as us. Will need to switch to blocking for writes or errors
    // occur just after a replug event.
    // No error checking. This really shouldn't fail, and even if it does,
    // we aren't so badly off.
    fcntl(laser_fd_, F_SETFL, fcntl(laser_fd_,F_GETFL,0) | O_NONBLOCK);

    struct flock fl;
    fl.l_type   = F_WRLCK;
    fl.l_whence = SEEK_SET;
    fl.l_start = 0;
    fl.l_len   = 0;
    fl.l_pid   = getpid();

    if (fcntl(laser_fd_, F_SETLK, &fl) != 0)
      HOKUYO_EXCEPT(hokuyo::Exception, "Device %s is already locked. Try 'lsof | grep %s' to find other processes that currently have the port open.", port_name, port_name);

    // Settings for USB?
    struct termios newtio;
    memset (&newtio, 0, sizeof (newtio));
    newtio.c_cflag = CS8 | CLOCAL | CREAD;
    newtio.c_iflag = IGNPAR;
    newtio.c_oflag = 0;
    newtio.c_lflag = ICANON;
    
    // activate new settings
    tcflush (laser_fd_, TCIFLUSH);
    if (tcsetattr (laser_fd_, TCSANOW, &newtio) < 0)
      HOKUYO_EXCEPT(hokuyo::Exception, "Unable to set serial port attributes. The port you specified (%s) may not be a serial port.", port_name); /// @todo tcsetattr returns true if at least one attribute was set. Hence, we might not have set everything on success.
    usleep (200000);

    // Some models (04LX) need to be told to go into SCIP2 mode...
    laserFlush();
    // Just in case a previous failure mode has left our Hokuyo
    // spewing data, we send reset the laser to be safe.
    try {
      reset();
    }
    catch (hokuyo::Exception &e)
    { 
      // This might be a device that needs to be explicitely placed in
      // SCIP2 mode. 
      // Note: Not tested: a device that is currently scanning in SCIP1.1
      // mode might not manage to switch to SCIP2.0.
      
      setToSCIP2(); // If this fails then it wasn't a device that could be switched to SCIP2.
      reset(); // If this one fails, it really is an error.
    }

    querySensorConfig();

    queryVersionInformation(); // In preparation for calls to get various parts of the version info.
  }
  catch (hokuyo::Exception& e)
  {
    // These exceptions mean something failed on open and we should close
    if (laser_port_ != NULL)
      fclose(laser_port_);
    laser_port_ = NULL;
    laser_fd_ = -1;
    throw e;
  }
}