Trait SizeHint 

pub trait SizeHint {
    // Required methods
    fn size_hint(data: &[u8], offset: usize) -> Result<usize, Error>;
    fn size_hint_(&self, data: &[u8], offset: usize) -> Result<usize, Error>;
}

The SizeHint trait provides a mechanism to return the encoded bytes size of a decodable type.

It defines two methods for retrieving the size of an encoded message:

These methods are crucial in decoding scenarios where the full size of the message is not immediately available, helping to determine how many bytes need to be read.

Required Methods

fn size_hint(data: &[u8], offset: usize) -> Result<usize, Error>

size_hint is a static method that takes the raw data and an offset and returns the total size of the encoded message. This is particularly useful for types where the encoded size may vary based on the contents of the data, and we need to calculate how much space is required for decoding.

fn size_hint_(&self, data: &[u8], offset: usize) -> Result<usize, Error>

size_hint_ is an instance method that performs the same function but allows the size to be be determined with respect to the current instance of the type.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl SizeHint for Vec<FieldMarker>

fn size_hint(_data: &[u8], _offset: usize) -> Result<usize, Error>

fn size_hint_(&self, data: &[u8], offset: usize) -> Result<usize, Error>

Implementors

impl SizeHint for FieldMarker

impl<T> SizeHint for T

where T: Fixed,