Re: Converting to using templates

Noah Roberts <>
Wed, 16 Apr 2008 08:07:40 -0700
tech wrote:

Hi, i have the following design issue. In our app we use different
codecs to encode/decode packets of data
I have defined a base codec class as follows

class CCodec
    CCodec() {};
    virtual ~CCodec(){};

    virtual unsigned char Encode(short ibuf ) = 0;

    virtual short Decode(unsigned char ibuf) = 0;

std::vector<unsigned char> m_SendBuffer; // defined in Voip class

bool Voip::SendData(signed short* buf, size_t size)
   for(int i = 0; i != ENC_BUF_LEN; ++i)
       SendBuffer[i] = m_codec->Encode(buf[i]); // m_Codec points to
concrete implementation

   // then SendDataToNetwork(SendBuffer)


ENC_BUF_LEN = size of the SendBuffer vector

What i need to do is send a packet of data to the network in the
SendData function
which is given some data, i've got type short above but it could be
any type ie char, long etc

the Encode function takes a short and returns a char (as thats what
compression does) however
as we will support different codecs the signature of this function
could vary, it would probably always
return a char but its input parameter could vary like with Send data.

The above is hardcoded to use shorts but i need something generic ,
can this be done with templates
some how?

What you seem to be saying is that SendData could have data other than
shorts and that the codec thing could be the same.

template< typename T >
bool SendData(T * buf, size_t s)
....buffer[i] = encode->Encode(buf[i]);

Same with CCodec except your encoder is probably going to have to work
with sizeof(T) instead of whatever hard coded value you have in there.

There are actually numerous options for doing the CCodec class,
including having it, itself be a template, its function Encode be a
template, or Encode being overridden per type.

This seem pretty basic, so maybe I don't understand the question.

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