Package dev.relism.flash.http2.frame

Class Padding

java.lang.Object

dev.relism.flash.http2.frame.Padding

public final class Padding
extends Object

RFC 9113 §6.1 (DATA) / §6.2 (HEADERS) padding. When FrameFlags.PADDED is set, a frame's payload is laid out as: 1 pad-length byte, then the actual data (or header-block fragment), then that many padding bytes (RFC 9113 gives no meaning to the padding bytes themselves — they exist only to obscure payload size from network observers).

Padding is not optional to support: any client may send it on DATA or HEADERS regardless of whether the server ever sends padded frames itself.

Flow control (forward note, not implemented here)

RFC 9113 §6.9.1: padding bytes count against the DATA flow-control window even though they carry no data — the whole frame payload (pad-length byte + data + padding) is what a #dataLength(long)}. This class only locates the data range within the payload; it performs no flow-control accounting itself.

Method Summary

Modifier and Type	Method	Description
static int	dataLength(long unpadded)	Extracts the data length from a value returned by unpad(byte[], int, int, boolean).
static int	dataOffset(long unpadded)	Extracts the data offset from a value returned by unpad(byte[], int, int, boolean).
static long	unpad(byte[] buf, int payloadOffset, int payloadLength, boolean padded)	Locates the actual data range within a payload that may or may not be padded.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

unpad

public static long unpad(byte[] buf,
 int payloadOffset,
 int payloadLength,
 boolean padded)

Locates the actual data range within a payload that may or may not be padded. When padded is false, returns the whole payload unchanged (zero-cost — no padding byte to read, no arithmetic beyond the pack). When true, reads the pad-length byte at buf[payloadOffset], validates it, and returns the data range that follows it.

Returns:

Pairs.pack(dataOffset, dataLength) — unpack with Pairs.hi(long)/Pairs.lo(long)

Throws:

Http2Exception - (PROTOCOL_ERROR) if padded is set but payloadLength == 0 (no room for the pad-length byte itself), or if the claimed pad length is greater than or equal to the whole payload length (RFC 9113 §6.1: "If the length of the padding is the length of the frame payload or greater, the recipient MUST treat this as a connection error")

dataOffset

public static int dataOffset(long unpadded)

Extracts the data offset from a value returned by unpad(byte[], int, int, boolean).

dataLength

public static int dataLength(long unpadded)

Extracts the data length from a value returned by unpad(byte[], int, int, boolean).