Thread: c++ string vs. c string

Code:

int decodehostname(string &buf, string &packet, unsigned int len, unsigned int pos) {
      unsigned int label;
      int bufpos = 0, r = 0;

      while(pos < len) {
            label = packet[pos++];

            if (label & 0xC0) {
                  if (pos >= len) return 0;
                  label = ((label & 0x3F) << 8) | packet[pos++];

                  if (r == 0) r = pos;
                  pos = label;

                  continue;
            }
            //printf("   bufpos: %d pos: %d label: %d\n   len: %d\n", bufpos, pos, label, len);
            if (label == 0)
                  break;

            //check
            if (bufpos + label + 1 >= 128) return 0;
            if (pos + label > len) return 0;

            string part = packet.substr(pos, label);
            buf.replace(bufpos, part.length() ,part );
            pos += label;
            bufpos += label;
            buf[bufpos++] = '.';
      }
      if (bufpos) bufpos--;
      buf[bufpos] = 0;

      return (r ? r : pos);
}

It's usually easier to use the C++ string class than C strings. They can do everything C arrays can, and if you need a C string you can use the .c_str() member function (which returns a const char *; if you need a modifiable C string then you need to use one).