msg.h

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#ifndef _ROS_MSG_H_
#define _ROS_MSG_H_
 
#include <stdint.h>
#include <stddef.h>
#include <string.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)
  {
    int32_t val;
    memcpy(&val, &f, sizeof(val));
 
    int16_t exp = ((val >> 23) & 255);
    uint32_t mantissa = val & 0x7FFFFF;
 
    if (exp == 255)
    {
      exp = 2047; // Special value for NaN, infinity etc.
    }
    else if (exp != 0)
    {
      exp += 1023 - 127; // Normal case
    }
    else if (!mantissa)
    {
      exp = 0; // Zero
    }
    else
    {
      // Denormalized value in float, will fit as normalized value in double
      exp += 1023 - 127;
      mantissa <<= 1;
      while (!(mantissa & 0x800000))
      {
          mantissa <<= 1;
          exp--;
      }
      mantissa &= 0x7FFFFF;
    }
 
    *(outbuffer++) = 0;
    *(outbuffer++) = 0;
    *(outbuffer++) = 0;
    *(outbuffer++) = (mantissa << 5) & 0xff;
    *(outbuffer++) = (mantissa >> 3) & 0xff;
    *(outbuffer++) = (mantissa >> 11) & 0xff;
    *(outbuffer++) = ((exp << 4) & 0xF0) | ((mantissa >> 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)
  {
    int16_t exp;
    uint32_t mantissa;
 
    // Skip lowest 24 bits
    inbuffer += 3;
 
    // Copy truncated mantissa.
    mantissa = ((uint32_t)(*(inbuffer++)) >> 4 & 0x0F);
    mantissa |= ((uint32_t)(*(inbuffer++)) & 0xff) << 4;
    mantissa |= ((uint32_t)(*(inbuffer++)) & 0xff) << 12;
    mantissa |= ((uint32_t)(*inbuffer) & 0x0f) << 20;
 
    // Copy exponent.
    exp = ((uint32_t)(*(inbuffer++)) & 0xf0) >> 4;
    exp |= ((uint32_t)(*inbuffer) & 0x7f) << 4;
 
    if (exp == 2047)
    {
      exp = 255; // NaN, infinity etc.
    }
    else if (exp - 1023 > 127)
    {
      exp = 255;
      mantissa = 0; // Too large for float, convert to infinity
    }
    else if (exp - 1023 >= -126)
    {
      exp -= 1023 - 127; // Normal case
    }
    else if (exp - 1023 < -150)
    {
      exp = 0; // Too small or zero
    }
    else
    {
      // Have to convert to denormalized representation for float
      mantissa |= 0x1000000;
      mantissa >>= ((-126 + 1023) - exp);
      exp = 0;
    }
 
    // Round off mantissa
    if (mantissa != 0xFFFFFF)
      mantissa += 1;
 
    mantissa >>= 1;
 
    // Put mantissa and exponent into place
    uint32_t val = mantissa;
    val |= static_cast<uint32_t>(exp) << 23;
 
    // Copy negative sign.
    val |= (static_cast<uint32_t>(*(inbuffer++)) & 0x80) << 24;
 
    memcpy(f, &val, sizeof(val));
    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