Myrddin
d605f2a826
The header was split into individual files to make it easier to manage. enums that were just a u8 or u16 with determinate values now are set in the definition instead of using const values. Errors were added. Some of these are just best guesses at what is needed at this time. Added a macro to the bits for checking buffer and mask length. This keeps the error generation consistent and makes the code easy to read. Started, but have not finished the packet stuff. I want it to have a view and a builder.
124 lines
3.1 KiB
Rust
124 lines
3.1 KiB
Rust
use crate::check_buffer_len;
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use crate::bits::*;
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use crate::error::PacketError;
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/// # Application Process Identifier
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///
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/// The APID shall provide the naming mechanism for the managed data path.
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///
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/// The APID may uniquely identify the individual sending or receiving application
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/// process within a particular space vehicle.
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///
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/// For Idle Packets the APID shall be ‘11111111111’.
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///
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/// ## NOTES
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/// - The APID is unique only within its naming domain.
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/// - There are no restrictions on the selection of APIDs except for the APID
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/// for Idle Packets stated above. In particular, APIDs are not required to
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/// be numbered consecutively.
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/// - The Recommended Standard used a reserved APID to carry specific PDUs by,
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/// for example, CFDP and LTP. This capability of acting as ‘shim’ protocol
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/// is preserved; that is, SPP can still carry PDUs of other protocols, but
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/// the coupling of APIDs to protocols is now mission specific. Missions may
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/// use the optional Packet Secondary Header to create an extended naming
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/// domain, but such uses are not specifically defined in this protocol.
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/// This is reflected by the fact that the only reserved value is now the
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/// one for Idle Packets.
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#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
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pub struct ApId
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{
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value: u16
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}
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impl ApId
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{
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/// The 16 bit version of the mask for the ApId bits in the header.
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pub const MASK_U16: u16 = 0b0000011111111111;
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/// The 8 bit array version of the mask for the ApId bits in the header.
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/// The
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pub const MASK_ARR: [u8; 2] = [0b00000111, 0b11111111];
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}
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impl From<u16> for ApId
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{
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fn from(value: u16) -> Self
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{
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ApId
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{
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value
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}
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}
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}
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impl From<ApId> for u16
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{
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fn from(apid: ApId) -> u16
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{
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apid.value
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}
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}
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impl FromBytes for ApId
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{
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type Error = PacketError;
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fn from_bytes(bytes: &[u8]) -> Result<Parsed<Self>, Self::Error>
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{
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check_buffer_len!(2usize, bytes);
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let id: u16 = (((bytes[0] & ApId::MASK_ARR[0]) as u16) << 8) |
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(((bytes[1] & ApId::MASK_ARR[1]) as u16));
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Ok(Parsed::new(2usize, id.into()))
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}
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}
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impl IntoBytes for ApId
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{
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type Error = PacketError;
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fn into_bytes(self, buffer: &mut [u8]) -> Result<usize, Self::Error>
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{
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check_buffer_len!(2usize, buffer);
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let id: u16 = self.value;
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buffer[0] = ((id >> 8) as u8) & ApId::MASK_ARR[0];
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buffer[1] = (id as u8) & ApId::MASK_ARR[1];
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Ok(2usize)
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}
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}
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impl FromBits for ApId
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{
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type Error = PacketError;
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fn from_bits(bytes: &[u8], mask: &[u8]) -> Result<Self, Self::Error>
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{
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check_buffer_len!(2usize, bytes, mask);
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let id: u16 = (((bytes[0] & mask[0]) as u16) << 8) |
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((bytes[1] & mask[1]) as u16);
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Ok(id.into())
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}
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}
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impl IntoBits for ApId
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{
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type Error = PacketError;
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fn into_bits(self, bytes: &mut [u8], mask: &[u8]) -> Result<(), Self::Error>
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{
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check_buffer_len!(2usize, bytes, mask);
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update_masked_bits_arr(&mut [bytes[0], bytes[1]], &[mask[0], mask[1]],
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&self.value.to_be_bytes());
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Ok(())
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}
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}
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