Serialize and deserialize packet header

[Ricardo G.]

Hi,

I can't find the problem in my method, it works until it reaches the part about the string.

The fields are:

///The fields in the class are
uint16_t          m_id;          
uint8_t           m_reserved;    
Ipv4Address       m_local;      
Ipv4Address       m_source;      
double            m_x;          
double            m_y;          
double            m_xVel;        
double            m_yVel;        
double            m_x1;          
double            m_y1;          
double            m_x2;          
double            m_y2;          
uint16_t          m_initialTime;
uint16_t          m_duration;    
std::string       m_message;


And the methods are:

uint32_t
DataHeader::GetSerializedSize () const
{
  return 79 + m_message.length() + 1; // 79 bytes for fields and 1 for string terminal ('\0')
}

void
DataHeader::Serialize (Buffer::Iterator i) const
{
  Buffer::Iterator start = i;
  i.WriteU16 (m_id);
  i.WriteU8 (m_reserved);
  WriteTo (i, m_local);
  WriteTo (i, m_source);
  i.WriteHtonU64 (m_x);
  i.WriteHtonU64 (m_y);
  i.WriteHtonU64 (m_xVel);
  i.WriteHtonU64 (m_yVel);
  i.WriteHtonU64 (m_x1);
  i.WriteHtonU64 (m_y1);
  i.WriteHtonU64 (m_x2);
  i.WriteHtonU64 (m_y2);
  i.WriteU16 (m_initialTime);
  i.WriteU16 (m_duration);

  char tmpBuffer [m_message.length() + 1];
  strcpy (tmpBuffer, m_message.c_str());
  i.Write ((uint8_t *)tmpBuffer, strlen(tmpBuffer) + 1);
}

uint32_t
DataHeader::Deserialize (Buffer::Iterator start)
{
  Buffer::Iterator i = start;
  m_id       = i.ReadU16 ();
  m_reserved = i.ReadU8 ();
  ReadFrom (i, m_local);
  ReadFrom (i, m_source);
  m_x    = i.ReadNtohU64 ();
  m_y    = i.ReadNtohU64 ();
  m_xVel = i.ReadNtohU64 ();
  m_yVel = i.ReadNtohU64 ();
  m_x1   = i.ReadNtohU64 ();
  m_y1   = i.ReadNtohU64 ();
  m_x2   = i.ReadNtohU64 ();
  m_y2   = i.ReadNtohU64 ();
  m_initialTime = i.ReadU16 ();
  m_duration    = i.ReadU16 ();

  uint8_t c;
  uint32_t len = 0;
  Buffer::Iterator i2 = i;

  do
    {
      c  = i2.ReadU8 ();
      len++;
    } while (c != 0);
  char tmpBuffer [len];
  start.Read ((uint8_t*)tmpBuffer, len);
  m_message = tmpBuffer;

  uint32_t dist = i.GetDistanceFrom (start);
  NS_ASSERT (dist == GetSerializedSize ());
  return dist;
}

I get the error: assert failed. cond="dist == GetSerializedSize ()" and printing the m_message and len variables I can see that it just reads 1 until the while condition it's satisfied and m_message gets garbage like this: Âôìûÿ

I''ve tried without the i2 variable.

Thank you.

[Tommaso Pecorella]

Hi,

dunno about the wrong (maybe) string length count, but for sure

  start.Read ((uint8_t*)tmpBuffer, len);

should be

  i.Read ((uint8_t*)tmpBuffer, len);

Hope this helps,

T

[Ricardo]

Hi, sorry I didn't point it out, but yes, I tried that.

My thinking was: use iterator i2 to count how many characters there are until a terminator ('\0') is found, then read that many bytes with iterator i. But it doesn't work.

Thanks.

[JaNa]

Hi,

I guess, yes,  Thar is happen.
How about try serialize and deserialize a char part alone as follow

virtual void Serialize (Buffer::Iterator start) const

{

  Buffer::Iterator it = start;

  int length = Astring.length();

  char str[length] = Astring.c_str();

  for (int i=0;i<length;i++)

    {

      it.WriteU8 (str[i]);

    }

}

virtual uint32_t Deserialize (Buffer::Iterator start)

{

  Buffer::iterator it = start;

  int length = GetSerializedSize();

  char str[length] = 0;

  for (int i=0;i<length;i++)

    {

      str[i] = it.ReadU8 ();

    }

  AString = string (str);

  return GetSerializedSize();

}

I guess this will help.

JaNa

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Best Regards..

    """""""""""
:)   JaNa     :) 
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