BitWrap

BitWrap is a derive macro and trait to declare a struct data member with explicit size, in bits.

BitWrapExt Trait

Trait declares 2 methods:

rust fn pack(&self, dst: &mut [u8]) -> Result<usize, BitWrapError>

pack method serialize struct fields into dst array

rust fn unpack(&mut self, src: &[u8]) -> Result<usize, BitWrapError>

unpack method deserialize struct fields from src array

BitWrap Macro

```rust use { core::convert::{ TryFrom, Infallible, }, std::net::Ipv4Addr, bitwrap::{ BitWrap, BitWrapExt, BitWrapError, }, };

[derive(Debug, PartialEq, Clone, Copy)]

enum Variant { Value55, ValueAA }

impl Default for Variant { fn default() -> Self { Variant::Value55 } }

impl TryFrom for Variant { type Error = BitWrapError; fn try_from(value: u8) -> Result { match value { 0x55 => Ok(Variant::Value55), 0xAA => Ok(Variant::ValueAA), _ => Err(BitWrapError), } } }

impl TryFrom for u8 { type Error = Infallible; fn try_from(value: Variant) -> Result { match value { Variant::Value55 => Ok(0x55), Variant::ValueAA => Ok(0xAA), } } }

[derive(BitWrap)]

struct Packet { // single bit field #[bitfield(1)] field_1: u8,

// bit field as boolean. 0 is false, otherwise is true
#[bitfield(1)]
field_2: bool,

// virtual field with option `name`
// unpack reads bits to the internall variable `_reserved`
// pack sets 6 bits from defined `value`
#[bitfield(6, name = _reserved, value = 0b111111)]

// use TryFrom<u8> for Variant
#[bitfield(8)]
variant: Variant,

// use TryFrom<u32> for Ipv4Addr
#[bitfield(32)]
ip: std::net::Ipv4Addr

// byte array
#[bitfield]
mac: [u8; 6],

// virtual field with optn `name` to define buffer length
#[bitfield(8, name = data_len, value = self.data.len())]

// get slice of `data_len` bytes and call BitWrapExt method for Vec<T>
// where T is u8 or with implemented BitWrapExt + Default traits
#[bitfield(data_len)]
data: Vec<u8>,

} ```