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180503.1 Paul Robinson Usage suggestion for LEB128 padding Improvement Accepted Paul Robinson


Section 7.6, pg 222

PROBLEM DESCRIPTION

Values in the LEB128 format are currently required to be minimum 
length; in some cases it may be advantageous to pad or align data 
by inserting leading zero or sign-extension bytes that don't affect 
the decoded value.

Discussion in a committee meeting revolved around whether to impose
limits on producers, or requirements on consumers.  The proposed 
change specifically does not imply that a producer could pad with 
*extra* bytes, but could simply not *remove* bytes from an ordinary
integer value; this avoids any suggestion that we could end up with
arbitrarily long LEB128 strings.

RESOLUTION

Section 7.6, pg 221, line 12, replace "be zero; discard them."
with "be zero, which may be discarded."

pg 222, line 13, add a new non-normative paragraph:

Some producers may choose to insert padding or alignment bytes by 
retaining (not discarding) one or more high-order bytes that would 
not affect the decoded value.

--
2021-04-19 Revised.  Previous version: http://dwarfstd.org/ShowIssue.php?issue=180503.1-1
2021-05-17 Accepted.


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