Module apdu 

APDU encoding and decoding per ASHRAE 135-2020 Clause 20.1.

Covers all eight PDU types:

• ConfirmedRequest (Clause 20.1.2)
• UnconfirmedRequest (Clause 20.1.3)
• SimpleAck (Clause 20.1.4)
• ComplexAck (Clause 20.1.5)
• SegmentAck (Clause 20.1.6)
• ErrorPdu (Clause 20.1.7)
• RejectPdu (Clause 20.1.8)
• AbortPdu (Clause 20.1.9)

Those owned PDUs need alloc. Without it, header reads and writes the header of an Unconfirmed-Request, an unsegmented Confirmed-Request or an unsegmented ComplexACK, borrowing the service parameters in place.

Modules

header

The fixed header of the APDUs that carry service parameters, read and written without an allocator (#1614): an Unconfirmed-Request, an unsegmented Confirmed-Request or ComplexACK, and an Error (Clauses 20.1.2, 20.1.3, 20.1.5 and 20.1.7); and the two answers that are all header, a Reject and an Abort (Clauses 20.1.8 and 20.1.9), so a device without a heap can refuse what it doesn’t serve (#1771).

Structs

AbortPdu

Abort PDU (Clause 20.1.9).

ComplexAck

ComplexACK PDU (Clause 20.1.5).

ConfirmedRequest

Confirmed-Request PDU (Clause 20.1.2).

ErrorPdu

Error PDU (Clause 20.1.7).

RejectPdu

Reject PDU (Clause 20.1.8).

SegmentAck

SegmentACK PDU (Clause 20.1.6).

SimpleAck

SimpleACK PDU (Clause 20.1.4).

UnconfirmedRequest

Unconfirmed-Request PDU (Clause 20.1.3).

Enums

Apdu

Sum type for all APDU PDU types.

Constants

MINIMUM_MESSAGE_SIZE

MinimumMessageSize: the smallest APDU any BACnet device accepts.

Functions

advertised_max_segments

The segment count a configured max-segments-accepted actually promises a peer.

decode_apdu

Decode an APDU from raw bytes.

encode_apdu

Encode an APDU to wire format.

is_valid_max_apdu_length

Return true when value is one of the BACnet max-APDU-length encodings defined by ASHRAE 135-2020 Clause 20.1.2.5.

max_apdu_header_at_or_below

Floor a raw local receive capacity to a Confirmed-Request header value.

validate_max_apdu_length

Validate an exact Confirmed-Request max-APDU-length header value. Only with alloc.

validate_max_segments

Validate a configured maximum segment count for a Confirmed-Request header.