qpack.h File Reference

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

#include "protocore_config.h"

Go to the source code of this file.

Classes
struct	QpackNs
	Dispatch table. Addressed by offset, so the layout is asserted below. More...

Typedefs
typedef proto_bool(*	QpackEmitFn) (void *ctx, const char *name, size_t name_len, const char *value, size_t value_len)
	Callback invoked for each decoded header; return false to abort the decode.

Functions
	PROTOCORE_NS_LAYOUT (QpackNs, encode_prefix, encode_header, decode)
size_t	protocore_qpack_encode_prefix (uint8_t *work, uint8_t *out, size_t cap)
	Write the encoded field-section prefix for a static-only section. .
size_t	protocore_qpack_encode_header (uint8_t *work, uint8_t *out, size_t cap, const char *name, size_t name_len, const char *value, size_t value_len)
	Encode one header field (server side): a full static match -> .
proto_bool	protocore_qpack_decode (uint8_t *work, const uint8_t *block, size_t len, char *scratch, size_t scratch_cap, QpackEmitFn emit, void *ctx)
	Decode a whole QPACK field section (prefix + representations), .

Variables
PROTOCORE_NS QpackNs Qpack	PROTOCORE_UNUSED
	Module namespace.

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 protocore_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.

work is bytes the CALLER holds. This module reads none of them: it carries nothing between calls, so there is no state to keep and nothing to wipe. The parameter is there so a caller drives every namespace the same way.

Author

Douglas Quigg (dstroy0)

Date

2026

Definition in file qpack.h.

Typedef Documentation

QpackEmitFn

typedef proto_bool(* QpackEmitFn)(void *ctx, const char *name, size_t name_len, const char *value, size_t value_len)

Callback invoked for each decoded header; return false to abort the decode.

Definition at line 39 of file qpack.h.

Function Documentation

PROTOCORE_NS_LAYOUT()

PROTOCORE_NS_LAYOUT	(	QpackNs	,
		encode_prefix	,
		encode_header	,
		decode
	)

protocore_qpack_encode_prefix()

size_t protocore_qpack_encode_prefix	(	uint8_t *	work,
		uint8_t *	out,
		size_t	cap
	)

Write the encoded field-section prefix for a static-only section. .

Parameters

work	PROTOCORE_QPACK_BORROW bytes the caller took. Not held past the call.
out	Out
cap	Cap

Returns

The size_t.

protocore_qpack_encode_header()

size_t protocore_qpack_encode_header	(	uint8_t *	work,
		uint8_t *	out,
		size_t	cap,
		const char *	name,
		size_t	name_len,
		const char *	value,
		size_t	value_len
	)

Encode one header field (server side): a full static match -> .

Parameters

work	PROTOCORE_QPACK_BORROW bytes the caller took. Not held past the call.
out	Out
cap	Cap
name	Name
name_len	Name len
value	Value
value_len	Value len

Returns

The size_t.

protocore_qpack_decode()

proto_bool protocore_qpack_decode	(	uint8_t *	work,
		const uint8_t *	block,
		size_t	len,
		char *	scratch,
		size_t	scratch_cap,
		QpackEmitFn	emit,
		void *	ctx
	)

Decode a whole QPACK field section (prefix + representations), .

Parameters

work	PROTOCORE_QPACK_BORROW bytes the caller took. Not held past the call.
block	Block
len	Len
scratch	caller buffer holding one header's name+value during each emit call
scratch_cap	Scratch cap
emit	Emit
ctx	Ctx

Returns

PROTO_TRUE on success.

Variable Documentation

PROTOCORE_UNUSED

PROTOCORE_NS QpackNs Qpack PROTOCORE_UNUSED

Initial value:

= {.encode_prefix = protocore_qpack_encode_prefix,
                                               .encode_header = protocore_qpack_encode_header,
                                               .decode = protocore_qpack_decode}

Module namespace.

Definition at line 89 of file qpack.h.