copyStringToBuf method
Copy the characters from str
into buf255.
Implementation
void copyStringToBuf(String str) {
if (str.length > 254) throw 'String too long: $str';
var index = 0;
for (var value in str.codeUnits) {
buf255.elementAt(index).value = value;
++index;
}
// null terminated C string
buf255.elementAt(index).value = 0;
}