getPropertyValue method

int getPropertyValue(int pnum)

Implementation

int getPropertyValue(int pnum) {
  var propNum = 999999;
  int addr = propertyTableStart;

  while (propNum > pnum) {
    propNum = propertyNumber(addr);

    var len = ZMachine.verToInt(Z.engine.version) <= 3 ||
            !BinaryHelper.isSet(Z.engine.mem.loadb(addr), 7)
        ? propertyLength(addr)
        : propertyLength(addr + 1);

    //not found (ref 12.4.1)
    if (len == 0) {
      return GameObject.getPropertyDefault(pnum);
    }

    if (propNum == pnum) {
      //ding ding ding

      if (len > 2) {
        throw GameException(
            'Only property length of 1 or 2 is supported by this function: $len');
      }

      if (len == 1) {
        return Z.engine.mem.loadb(addr + 1);
      } else {
        return Z.engine.mem.loadw(addr + 1);
      }
    }

    //skip to the next property
    if (ZMachine.verToInt(Z.engine.version) <= 3) {
      addr += (len + 1);
    } else {
      //if property len > 2, account for the second
      //size byte in the header
      addr += (len + ((len > 2) ? 2 : 1));
    }
  }

  //return default property instead (ref 12.4.1)
  return GameObject.getPropertyDefault(pnum);
}