/**
* Return -1 if the code is not valid
*        0  if the code is valid but out of date
*        1  if the code is valid and under 2 years
*        2  for the demo code
*/
gint gc_activation_check(const char *code)
{
#ifdef  DISABLE_ACTIVATION_CODE
  return 1;
#else
  int value = 0;
  int i;
  char crc1 = 0;
  char crc2 = 0;
  char codeddate[5];

  if (properties->administration)
    return 1;

  if(strlen(code) != 6)
    return -1;

  // A special code to test the full version without
  // saving the activation
  if (strncmp(code, "THANKS", 6) == 0)
    {
      return 2;
    }

  for(i=3; i>=0; i--)
    {
      value |= code [i]& 0x07;
      value = value << 3;
      crc1 = (crc1 ^ code[i]) & 0x07;
    }
  value = value >> 3;
  crc1 = 0x30 | crc1;
  crc2 = 0x30 | (code[2] ^ code[3]);

  if(crc1 != code[4])
    return(-1);

  if(crc2 != code[5])
    return(-1);

  codeddate[3] = 0x30 | (value & 0x000F);
  value = value >> 4;

  codeddate[2] = 0x30 | (value & 0x0001);
  value = value >> 1;

  codeddate[1] = 0x30 | (value & 0x000F);
  value = value >> 4;

  codeddate[0] = 0x30 | (value & 0x0003);
  codeddate[4] = '\0';

  if(atoi(codeddate) + 200 >= atoi(BUILD_DATE))
    return(1);
  else
    return(0);
#endif
}