Trait SequenceHint 

pub trait SequenceHint: Sized + Sealed {
    // Required method
    fn get(self) -> Option<usize>;

    // Provided methods
    fn require<C>(self, cx: C) -> Result<usize, C::Error>
       where C: Context { ... }
    fn size_hint(self) -> SizeHint { ... }
}

A size hint passed in when encoding or decoding a sequence.

Examples

use musli_core::hint::SequenceHint;

fn get_sequence_size<H>(hint: H) -> Option<usize>
where
    H: SequenceHint,
{
    hint.get()
}

// Known size hint
let size = get_sequence_size(10usize);
assert_eq!(size, Some(10));

// Optional size hint with value
let size = get_sequence_size(Some(7usize));
assert_eq!(size, Some(7));

// Optional size hint without value
let size = get_sequence_size(None::<usize>);
assert_eq!(size, None);

Required Methods

fn get(self) -> Option<usize>

Get an optional sequence hint.

Provided Methods

fn require<C>(self, cx: C) -> Result<usize, C::Error>

where C: Context,

Require a sequence hint or raise an error indicating that the format doesn’t support sequences of unknown size if one is not present.

fn size_hint(self) -> SizeHint

Coerce into a [SizeHint].

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 SequenceHint for Option<usize>

fn get(self) -> Option<usize>

impl SequenceHint for usize

fn get(self) -> Option<usize>

fn require<C>(self, _: C) -> Result<usize, C::Error>

where C: Context,

fn size_hint(self) -> SizeHint

Implementors