Struct CrcSpacePacket

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pub struct CrcSpacePacket<'a, 'b> { /* private fields */ }

Expand description

A wrapper around a SpacePacket that automatically manages a trailing CRC-16 checksum.

Implementations§

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impl<'a, 'b> CrcSpacePacket<'a, 'b>

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pub fn new( buffer: &'a mut [u8], apid: Apid, packet_type: PacketType, sequence_count: SequenceCount, secondary_header_flag: SecondaryHeaderFlag, sequence_flag: SequenceFlag, data_field_len: u16, crc_alg: &'b Crc<u16>, ) -> Result<CrcSpacePacket<'a, 'b>, CrcError>

Creates a new CRC-protected Space Packet in the provided buffer.

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pub fn set_data<T: SpacePacketData>( &mut self, data: &T, ) -> Result<(), DataFieldError>

Writes data to the packet’s data field and automatically updates the CRC.

This is the safe, CRC-aware way to set the packet’s payload.

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pub fn data_as<T: SpacePacketData>(&self) -> Result<&T, CrcError>

Validates the CRC and returns a typed, zero-copy view of the data field.

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pub fn data(&self) -> Result<&[u8], CrcError>

Validates the CRC and returns an immutable slice of the data field.

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pub fn validate(&self) -> Result<(), CrcError>

Validates the current CRC against the packet’s contents.

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pub fn update_crc(&mut self)

Forces a recalculation and update of the CRC value. This is called automatically by set_data_field.

Methods from Deref<Target = SpacePacket>§

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pub fn set_data_field<T: SpacePacketData>( &mut self, data: &T, ) -> Result<(), DataFieldError>

Copies a user-defined data structure into the packet’s data field.

The size of T must exactly match the length of the data field.

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pub fn data_as<T: SpacePacketData>(&self) -> Result<&T, DataFieldError>

Returns a zero-copy, typed view of the packet’s data field.

This is the primary method for interpreting the packet’s payload as a specific data structure. It will fail if the size of T does not match the data field’s length.

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pub fn data_field(&self) -> &[u8] ⓘ

Returns an immutable slice of the packet’s data field.

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pub fn data_field_mut(&mut self) -> &mut [u8] ⓘ

Returns a mutable slice of the packet’s data field.

Warning: Modifying the data field directly will invalidate any CRC checksum. If using a CrcSpacePacket, prefer the safe set_data() method instead.

Methods from Deref<Target = PrimaryHeader>§

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pub fn version(&self) -> PacketVersion

Returns the 3-bit packet version number.

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pub fn set_version(&mut self, version: PacketVersion)

Sets the 3-bit packet version number.

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pub fn packet_type(&self) -> PacketType

Returns the PacketType (Telemetry or Telecommand).

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pub fn set_packet_type(&mut self, packet_type: PacketType)

Sets the PacketType (Telemetry or Telecommand).

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pub fn secondary_header_flag(&self) -> SecondaryHeaderFlag

Returns the SecondaryHeader flag (Present or Absent).

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pub fn set_secondary_header_flag(&mut self, flag: SecondaryHeaderFlag)

Sets the SecondaryHeader flag (Present or Absent).

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pub fn apid(&self) -> Apid

Returns the 11-bit Application Process Identifier (Apid).

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pub fn set_apid(&mut self, apid: Apid)

Sets the 11-bit Application Process Identifier (Apid).

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pub fn sequence_flag(&self) -> SequenceFlag

Returns the 2-bit SequenceFlag.

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pub fn set_sequence_flag(&mut self, flag: SequenceFlag)

Sets the 2-bit SequenceFlag.

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pub fn sequence_count(&self) -> SequenceCount

Returns the 14-bit packet sequence count.

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pub fn set_sequence_count(&mut self, count: SequenceCount)

Sets the 14-bit SequenceCount.

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pub fn data_field_len(&self) -> usize

Returns the length of the data field in bytes as specified by the header.

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pub fn set_data_field_len(&mut self, len: u16)

Sets the length of the data field in bytes. The value written to the header will be len - 1 as per the CCSDS standard.

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pub fn packet_len(&self) -> usize

Returns the total length of the packet (header + data field) in bytes.

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pub fn cfe_msg_id(&self) -> u16

Reconstructs the CFE-style Message ID (MsgId) from the primary header fields.

This is a crucial convenience function for systems that interact with the cFE Software Bus (SB). The SB uses a single integer MsgId for routing, which is a composite value created from several fields in the CCSDS header.

A cFE MsgId is 16-bit integer with the following structure:

+-----------------+------+-----------------------------------------+
| Field           | Size | Description                             |
+-----------------+------+-----------------------------------------+
| APID            | 11   | The 11-bit Application Process ID.      |
| SB Flag         | 1    | 1 indicates a Software Bus message.     |
| Type            | 1    | 0 for Telemetry, 1 for Telecommand.     |
| Reserved        | 3    | Unused, should be zero.                 |
+-----------------+------+-----------------------------------------+