Class WssFrameCodec

Frame codec implementing a SLIP-like protocol:

• END (0xC0) terminates a frame.
• ESC (0xDB) escapes special bytes inside the frame.
• END_SUB (0xDC) represents END when escaped.
• ESC_SUB (0xDD) represents ESC when escaped.

Frames on the wire are [sender][target][payload...][checksum][END]. The checksum is computed over all bytes except the last two (checksum + END).

Inheritance

object

WssFrameCodec

Implements

IFrameCodec

Namespace: Wss.CoreModule

Assembly: WSS_Core_Interface.dll

Syntax

public sealed class WssFrameCodec : IFrameCodec

Methods

Deframe(byte[])

Progressive deframer: feed any-size incoming chunks and get back zero or more complete, unescaped frames. Each returned frame has the format [sender][target][payload...][checksum] (END is consumed).

Declaration

public IEnumerable<byte[]> Deframe(byte[] chunk)

Parameters

Type	Name	Description
byte[]	chunk	A raw byte chunk from the transport (may be partial or contain multiple frames).

Returns

Type	Description
IEnumerable<byte[]>	0..N complete, unescaped frames (END removed). Checksum is not validated here.

Frame(byte, byte, byte[])

Builds a wire-safe frame for transmission using SLIP-style escaping. Output format (before escaping): [sender][target][payload...][checksum][END].

Declaration

public byte[] Frame(byte sender, byte target, byte[] payload)

Parameters

Type	Name	Description
byte	sender	Sender address byte.
byte	target	Target/receiver address byte (e.g., device address or broadcast).
byte[]	payload	The protocol payload (e.g., [cmd][len][...]). The codec does not modify the payload.

Returns

Type	Description
byte[]	Escaped frame ready to send (always terminates with END).

TryUnescapeAndValidate(ReadOnlySpan<byte>, out byte[])

Attempts to unescape and validate a single frame (without END), returning false if the checksum does not match. Useful if you want checksum enforcement at the codec layer.

Declaration

public static bool TryUnescapeAndValidate(ReadOnlySpan<byte> preEscaped, out byte[] output)

Parameters

Type	Name	Description
ReadOnlySpan<byte>	preEscaped	Escaped frame bytes (without the END terminator).
byte[]	output	On success, the unescaped frame [sender][target][payload...][checksum]. On failure, System.Array.Empty<T>() is returned.

Returns

Type	Description
bool	true if the checksum is valid; otherwise false.

Implements

IFrameCodec