msg.h

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#ifndef _ROS_MSG_H_
#define _ROS_MSG_H_

#include <stdint.h>
#include <stddef.h>

namespace ros
{

/* Base Message Type */
class Msg
{
public:
  virtual int serialize(unsigned char *outbuffer) const = 0;
  virtual int deserialize(unsigned char *data) = 0;
  virtual const char * getType() = 0;
  virtual const char * getMD5() = 0;

  static int serializeAvrFloat64(unsigned char* outbuffer, const float f)
  {
    const int32_t* val = (int32_t*) &f;
    int32_t exp = ((*val >> 23) & 255);
    if (exp != 0)
    {
      exp += 1023 - 127;
    }

    int32_t sig = *val;
    *(outbuffer++) = 0;
    *(outbuffer++) = 0;
    *(outbuffer++) = 0;
    *(outbuffer++) = (sig << 5) & 0xff;
    *(outbuffer++) = (sig >> 3) & 0xff;
    *(outbuffer++) = (sig >> 11) & 0xff;
    *(outbuffer++) = ((exp << 4) & 0xF0) | ((sig >> 19) & 0x0F);
    *(outbuffer++) = (exp >> 4) & 0x7F;

    // Mark negative bit as necessary.
    if (f < 0)
    {
      *(outbuffer - 1) |= 0x80;
    }

    return 8;
  }

  static int deserializeAvrFloat64(const unsigned char* inbuffer, float* f)
  {
    uint32_t* val = (uint32_t*)f;
    inbuffer += 3;

    // Copy truncated mantissa.
    *val = ((uint32_t)(*(inbuffer++)) >> 5 & 0x07);
    *val |= ((uint32_t)(*(inbuffer++)) & 0xff) << 3;
    *val |= ((uint32_t)(*(inbuffer++)) & 0xff) << 11;
    *val |= ((uint32_t)(*inbuffer) & 0x0f) << 19;

    // Copy truncated exponent.
    uint32_t exp = ((uint32_t)(*(inbuffer++)) & 0xf0) >> 4;
    exp |= ((uint32_t)(*inbuffer) & 0x7f) << 4;
    if (exp != 0)
    {
      *val |= ((exp) - 1023 + 127) << 23;
    }

    // Copy negative sign.
    *val |= ((uint32_t)(*(inbuffer++)) & 0x80) << 24;

    return 8;
  }

  // Copy data from variable into a byte array
  template<typename A, typename V>
  static void varToArr(A arr, const V var)
  {
    for (size_t i = 0; i < sizeof(V); i++)
      arr[i] = (var >> (8 * i));
  }

  // Copy data from a byte array into variable
  template<typename V, typename A>
  static void arrToVar(V& var, const A arr)
  {
    var = 0;
    for (size_t i = 0; i < sizeof(V); i++)
      var |= (arr[i] << (8 * i));
  }

};

}  // namespace ros

#endif