Returns the 2-byte abort sequence (0xFF, 0x00) to transmit if a prior Flush() has already sent bytes of the current frame on the wire, or an empty span if nothing has been flushed yet.

Call Reset() after aborting before starting a new frame.

Appends bytes to the unencoded payload.

Precondition

size() + bytes.size() <= max_size().

Pointer to the unencoded payload region ([data(), data() + size())).

Warning

Invalidated by Encode(), which overwrites the internal buffer in-place. Call clear() or resize() before writing a new payload.

Decodes a single 0x00-terminated COBS frame encoded into output.

Precondition

encoded and output must not overlap.

Returns

A Result containing the decoded payload subspan of output on success or one of the following error codes on failure:

• DATA_LOSS: encoded is not a valid 0x00-terminated COBS frame.
• RESOURCE_EXHAUSTED: output is too small to hold the decoded payload. Sizing output to MaxDecodedSize(encoded.size()) guarantees success.

Constructs a Decoder that writes decoded payloads into decode_buffer.

Size decode_buffer to the maximum expected decoded payload length (or use DecoderBuffer<kMaxPayloadSize>).

Encodes the current size() payload bytes in-place and returns the resulting 0x00-terminated COBS frame.

Postcondition

The returned span is valid until the next mutation or Encode() call on this EncodeBuffer. Because Encode() overwrites the buffer in-place, call clear() or resize() before building a new payload.

Encodes input into output as a 0x00-terminated COBS frame.

Precondition

input and output must not overlap (use EncodeInPlace() or EncodeBuffer for in-place encoding).

Returns

A Result containing the encoded frame subspan of output (including trailing 0x00) on success or one of the following error codes on failure:

• RESOURCE_EXHAUSTED: output is too small to hold the encoded frame. Sizing output to MaxEncodedSize(input.size()) guarantees success.

Resizes the payload to payload_size bytes (for payloads written directly via data()) and encodes in-place.

Precondition

payload_size <= max_size().

Postcondition

Same as Encode().

Encodes a payload in-place inside buffer, appending a trailing 0x00 frame delimiter.

Prefer EncodeBuffer<kMaxPayloadSize> when allocating a fixed-capacity buffer on the stack or inside a class. Use EncodeInPlace directly when operating on an externally provided ByteSpan.

Precondition

buffer.size() >= MaxEncodedSize(payload_size).

The unencoded payload must be written at buffer.subspan(1, payload_size) before calling EncodeInPlace (buffer[0] must be left reserved in front of the payload).

Returns

A Result containing the encoded frame subspan at the start of buffer (including trailing 0x00) on success or one of the following error codes on failure:

• RESOURCE_EXHAUSTED: buffer.size() < MaxEncodedSize(payload_size).

Finalizes the frame (appending the trailing 0x00 delimiter), resets the streamer for the next frame (emit_leading_delimiter = false), and returns the final wire chunk to transmit.

Postcondition

The returned ByteSpan points into buffer and remains valid until the next Write() or Reset() call.

Drains completed output from the buffer and returns the wire chunk to transmit.

Returns an empty span if no complete block is ready to flush yet.

Postcondition

The returned ByteSpan points into buffer and remains valid until the next Write(), Flush(), Finish(), or Reset() call.

Returns true if a frame is currently being assembled (at least one non-zero byte has been received since the last 0x00 delimiter or Clear()).

Returns the maximum possible decoded payload size in bytes for a 0x00-terminated COBS frame of encoded_size bytes.

Use this to size output buffers passed to Decode() or Decoder.

Returns the worst-case encoded frame size in bytes for a payload of unencoded_size bytes, including the trailing 0x00 delimiter.

Use this to size output buffers passed to Encode() or EncodeInPlace().

Processes a chunk of incoming wire bytes and invokes callback with a Result<ByteSpan> (Ok, DataLoss, or ResourceExhausted) for each frame that terminates within data.

Postcondition

Each ByteSpan passed to callback points into decode_buffer and is only valid for the duration of that callback invocation.

Processes a single incoming wire byte b.

The decoder automatically resets at every 0x00 delimiter (whether the frame succeeded or failed), so the next byte begins a new frame without calling Clear().

Returns

• UNAVAILABLE: Frame assembly is still in progress (or an idle 0x00 delimiter was ignored).
• OK: A valid frame completed on a 0x00 delimiter. The returned ByteSpan points into decode_buffer and remains valid until the next Process() or Clear() call.
• DATA_LOSS: A malformed or truncated frame ended at 0x00.
• RESOURCE_EXHAUSTED: The decoded payload exceeded decode_buffer.size() (reported when the frame's closing 0x00 delimiter arrives).

Appends a single byte to the unencoded payload.

Precondition

size() < max_size().

Discards any buffered state and prepares to encode a new frame.

Parameters

emit_leading_delimiter

If true, prepends a leading 0x00 delimiter byte to the first chunk of the new frame.

Sets the unencoded payload length to new_size bytes.

Precondition

new_size <= max_size().

Constructs a Streamer that writes encoded chunks into buffer.

Precondition

buffer.size() >= kMinBufferSize to stream arbitrary payloads (or use StreamerBuffer<>, which provides the buffer automatically).

Parameters

emit_leading_delimiter

If true, prepends a leading 0x00 delimiter byte to the first emitted chunk to flush any prior line noise on the receiver.

Encodes as much of data as fits into the output buffer and returns the unconsumed remainder of data.

Postcondition

If the returned span is empty, all of data was consumed and you may call Write() with the next payload piece or Finish() to end the frame.

If the returned span is non-empty, the output buffer is ready to drain: call Flush(), transmit that chunk, and pass the returned remainder back to Write().

2-byte sequence (0xFF, 0x00) that aborts an in-progress frame on the wire so the receiver discards it with DATA_LOSS.

Minimum buffer size (257 bytes) required to stream arbitrarily large frames across multiple Flush() calls.

Decodes a single 0x00-terminated COBS frame encoded into output.

Precondition

encoded and output must not overlap.

Returns

A Result containing the decoded payload subspan of output on success or one of the following error codes on failure:

• DATA_LOSS: encoded is not a valid 0x00-terminated COBS frame.
• RESOURCE_EXHAUSTED: output is too small to hold the decoded payload. Sizing output to MaxDecodedSize(encoded.size()) guarantees success.

Encodes input into output as a 0x00-terminated COBS frame.

Precondition

input and output must not overlap (use EncodeInPlace() or EncodeBuffer for in-place encoding).

Returns

A Result containing the encoded frame subspan of output (including trailing 0x00) on success or one of the following error codes on failure:

• RESOURCE_EXHAUSTED: output is too small to hold the encoded frame. Sizing output to MaxEncodedSize(input.size()) guarantees success.