pad method
void
pad()
Implementation
void pad() {
int pad = 0;
int mod = _offset! % 4;
if (mod > 0) {
pad = 4 - mod;
}
while (pad-- > 0) {
int b = readByte(false);
if (b == -129) {
break;
}
if (b != 0) {
throw Exception("non-zero padding");
}
}
}