lead bytes

Definition

In order to avoid confusion with the use of the term pad character, when pre-padding with bytes that are not replaced later, we use the term lead bytes. So lead-bytes are added "pre-conversion".

CESR related

The term pad may be confusing not merely because both ways use a type of padding but it is also true that the number of pad characters when padding post-conversion equals the number of lead bytes when padding pre-conversion.