Module encode 

Encoding a header block.

Deliberately the simplest legal encoder. Every header goes out either as a bare static-table index, when name and value match one exactly, or as a literal without indexing — never Huffman-coded, never entered into a table.

Why give up the compression

Because the alternative is the hardest bug in HPACK. An encoder that indexes has to keep a table in lockstep with the peer’s copy of it, and a divergence does not fail: it makes the peer read subsequent headers as different headers. There is nothing to diverge here.

The cost is bytes on a connection that carries two request shapes, both of them tiny next to the map responses coming back the other way. That is a good trade for a class of bug that would be very hard to find.

Functions

encode_header

Append a header to out, returning the new length.

encode_integer

RFC 7541 section 5.1, with flags supplying the bits above the prefix.