embedded_linux_hardware.h

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#ifndef ROS_EMBEDDED_LINUX_HARDWARE_H_
#define ROS_EMBEDDED_LINUX_HARDWARE_H_

#include <iostream>

#ifdef BUILD_LIBROSSERIALEMBEDDEDLINUX
extern "C" int elCommInit(char *portName, int baud);
extern "C" int elCommRead(int fd);
extern "C" elCommWrite(int fd, uint8_t* data, int length);
#endif

#ifdef __linux__
#include <time.h>
#endif

// Includes necessary to support time on OS X.
#ifdef __MACH__
#include <mach/mach.h>
#include <mach/mach_time.h>
static mach_timebase_info_data_t    sTimebaseInfo;
#endif

#define DEFAULT_PORT "/dev/ttyAM1"

class EmbeddedLinuxHardware
{
public:
  EmbeddedLinuxHardware(const char *pn, long baud = 57600)
  {
    strncpy(portName, pn, 30);
    baud_ = baud;
  }

  EmbeddedLinuxHardware()
  {
    const char *envPortName = getenv("ROSSERIAL_PORT");
    if (envPortName == NULL)
      strcpy(portName, DEFAULT_PORT);
    else
      strncpy(portName, envPortName, 29);
    portName[29] = '\0'; // in case user gave us too long a port name
    baud_ = 57600;
  }

  void setBaud(long baud)
  {
    this->baud_ = baud;
  }

  int getBaud()
  {
    return baud_;
  }

  void init()
  {
    fd = elCommInit(portName, baud_);
    if (fd < 0)
    {
      std::cout << "Exiting" << std::endl;
      exit(-1);
    }
    std::cout << "EmbeddedHardware.h: opened serial port successfully\n";

    initTime();
  }

  void init(const char *pName)
  {
    fd = elCommInit(pName, baud_);
    if (fd < 0)
    {
      std::cout << "Exiting" << std::endl;
      exit(-1);
    }
    std::cout << "EmbeddedHardware.h: opened comm port successfully\n";

    initTime();
  }

  int read()
  {
    int c = elCommRead(fd);
    return c;
  }

  void write(uint8_t* data, int length)
  {
    elCommWrite(fd, data, length);
  }

#ifdef __linux__
  void initTime()
  {
    clock_gettime(CLOCK_MONOTONIC, &start);
  }

  unsigned long time()
  {
    struct timespec end;
    long seconds, nseconds;

    clock_gettime(CLOCK_MONOTONIC, &end);

    seconds  = end.tv_sec  - start.tv_sec;
    nseconds = end.tv_nsec - start.tv_nsec;

    return ((seconds) * 1000 + nseconds / 1000000.0) + 0.5;
  }

#elif __MACH__
  void initTime()
  {
    start = mach_absolute_time();
    mach_timebase_info(&sTimebaseInfo);
  }

  unsigned long time()
  {
    // See: https://developer.apple.com/library/mac/qa/qa1398/_index.html
    uint64_t elapsed = mach_absolute_time() - start;
    return elapsed * sTimebaseInfo.numer / (sTimebaseInfo.denom * 1000000);
  }
#endif

protected:
  int fd;
  char portName[30];
  long baud_;

#ifdef __linux__
  struct timespec start;
#elif __MACH__
  uint64_t start;
#endif
};

#endif