Re: [quicwg/base-drafts] Seek more clarity on Largest Reference/Base Index encoding (#1403)

afrind <notifications@github.com> Fri, 01 June 2018 23:31 UTC

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Subject: Re: [quicwg/base-drafts] Seek more clarity on Largest Reference/Base Index encoding (#1403)
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afrind commented on this pull request.



>  
-    baseIndex = largestReference + deltaBaseIndex
+To save space, Base Index is encoded relative to Largest Reference using a
+one-bit sign and the `Delta Base Index` value.  A sign bit of 0 indicates that
+the Base Index has a greater absolute index than the Largest Reference; the

I don't see where this sentence says it added entries - are you referring to somewhere else?  I think Mike's right here - if the Base Index is equal to LR then the sign bit will be 0.  The original text had that, and it's included on lines 578-9 below.  Is it clearer if we bring it back up here?

I agree we don't need to mention the case where they are both 0 here. 

>  
-    baseIndex = largestReference + deltaBaseIndex
+To save space, Base Index is encoded relative to Largest Reference using a
+one-bit sign and the `Delta Base Index` value.  A sign bit of 0 indicates that
+the Base Index has a greater absolute index than the Largest Reference; the
+value of Delta Base Index is added to the Largest Reference to determine the
+absolute value of the Base Index.  A sign bit of 1 indicates that the Base Index
+is smaller than the Base Index.  That is:

Base Index is smaller than the Largest Reference

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