Detailed Description

QPACK field-section compression for HTTP/3 (RFC 9204).

QPACK is HTTP/3's header compression. It reuses RFC 7541's prefix-integer coding and Huffman code (shared here via hpack_prim.h) and adds a 99-entry static table, an encoded field-section prefix, and its own field-line representations.

This codec is static-table-only and needs no per-connection state: the encoder emits indexed / literal representations against the static table (never inserting into a dynamic table), and it advertises SETTINGS_QPACK_MAX_TABLE_CAPACITY = 0, so a conformant peer's encoder never sends a dynamic-table reference. The decoder therefore rejects (returns false) any representation that references the dynamic table or a non-zero Required Insert Count. Pure, zero heap, host-tested against the RFC 9204 Appendix B.1 worked example.

Author: Douglas Quigg (dstroy0)

Date: 2026

Definition in file qpack.h.