Re: forming an ipv6 address string from unsigned char array

From:

Oncaphillis <oncaphillis@snafu.de>

Newsgroups:

comp.lang.c++

Date:

Tue, 01 Apr 2008 14:31:12 +0200

Message-ID:

<65eo8gF29b2roU1@mid.uni-berlin.de>

sam.barker0@gmail.com wrote:

Hi,
How can I convert an unsigned char array containing IPV6 address into
a string
Eg
if arrray contains
20 01 05 03 a8 3e 00 00 00 00 00 00 00 02 00 30

Then the address is
Addr: 2001:0503:a83e:0000:0000:0000:0002:0030

I tried to do write like below but then its completely wrong.Is there
any cast for hex
for(int i=0;i<=15;i++)
{
oss << static_cast<unsigned int>(*(Rec.GetStart()+i));

Cheers,
Sam

How's about this ?

<snip>

#include <iostream>
#include <iomanip>
#include <sstream>

const unsigned char * cs =
  (const unsigned char *)
   "20 01 05 03 a8 3e 00 00 00 00 00 00 00 02 00 30";

int main() {
   std::stringstream is((const char*)cs);
   std::stringstream os;

   int i;

   for(i=0;i<16 && is;i++) {
     unsigned int n;

     is >> std::hex >> n;

     if(!is || n > 0xff) {
       std::cerr << "failed to read (valid) number";
       return -1;
     }

     os << (i % 2 || i==0 ? "" : ":")
          << std::hex << std::setw(2) << std::setfill('0') << n;
   }

   if(i!=16) {
     std::cerr << "failed to eat up string" << std::endl;
     return -1;
   }

   std::cerr << os.str() << std::endl;
}

</snip>

Hope that helps

o.