Struct binary_layout::WrappedField

pub struct WrappedField<U, T: LayoutAs<U>, F: Field> { /* private fields */ }

A WrappedField is a Field that, unlike PrimitiveField, does not directly represents a primitive type. Instead, it represents a wrapper type that can be converted to/from a primitive type using the LayoutAs trait. See Field for more info on this API.

Example:

use binary_layout::{prelude::*, LayoutAs};

struct MyIdType(u64);
impl LayoutAs<u64> for MyIdType {
  fn read(v: u64) -> MyIdType {
    MyIdType(v)
  }

  fn write(v: MyIdType) -> u64 {
    v.0
  }
}

define_layout!(my_layout, BigEndian, {
  // ... other fields ...
  field: MyIdType as u64,
  // ... other fields ...
});

fn func(storage_data: &mut [u8]) {
  // read some data
  let read_data: MyIdType = my_layout::field::read(storage_data);
  // equivalent: let read_data = MyIdType(u16::from_le_bytes((&storage_data[0..2]).try_into().unwrap()));

  // write some data
  my_layout::field::write(storage_data, MyIdType(10));
  // equivalent: data_slice[18..22].copy_from_slice(&10u32.to_le_bytes());
}

Trait Implementations

impl<U, T: LayoutAs<U>, F: Field> Field for WrappedField<U, T, F>

type Endian = <F as Field>::Endian

See Field::Endian

const OFFSET: usize = F::OFFSET

See Field::OFFSET

const SIZE: Option<usize> = F::SIZE

See Field::SIZE

impl<U, T: LayoutAs<U>, F: FieldCopyAccess<HighLevelType = U>> FieldCopyAccess for WrappedField<U, T, F>

type HighLevelType = T

See FieldCopyAccess::HighLevelType

fn read(storage: &[u8]) -> Self::HighLevelType

Read the field from a given data region, assuming the defined layout, using the Field API.

Example:

use binary_layout::{prelude::*, LayoutAs};

#[derive(Debug, PartialEq, Eq)]
struct MyIdType(u64);
impl LayoutAs<u64> for MyIdType {
  fn read(v: u64) -> MyIdType {
    MyIdType(v)
  }

  fn write(v: MyIdType) -> u64 {
    v.0
  }
}

define_layout!(my_layout, LittleEndian, {
  //... other fields ...
  some_integer_field: MyIdType as u64,
  //... other fields ...
});

fn func(storage_data: &mut [u8]) {
  my_layout::some_integer_field::write(storage_data, MyIdType(50));
  assert_eq!(MyIdType(50), my_layout::some_integer_field::read(storage_data));
}

fn write(storage: &mut [u8], v: Self::HighLevelType)

Write the field to a given data region, assuming the defined layout, using the Field API.

Example:

See FieldCopyAccess::read for an example