Trait ReaderSegments 

pub trait ReaderSegments {
    // Required method
    fn get_segment(&self, idx: u32) -> Option<&[u8]>;

    // Provided methods
    fn len(&self) -> usize { ... }
    fn is_empty(&self) -> bool { ... }
}

An object that manages the buffers underlying a Cap’n Proto message reader.

Required Methods

fn get_segment(&self, idx: u32) -> Option<&[u8]>

Gets the segment with index idx. Returns None if idx is out of range.

The segment must be 8-byte aligned or the “unaligned” feature must be enabled in the capnp crate. (Otherwise reading the segment will return an error.)

The returned slice is required to point to memory that remains valid until the ReaderSegments object is dropped. In safe Rust, it should not be possible to violate this requirement.

Provided Methods

fn len(&self) -> usize

Gets the number of segments.

fn is_empty(&self) -> bool

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<I> ReaderSegments for Vec<I>

where I: AsRef<[u8]>,

Available on crate feature alloc only.

fn get_segment(&self, id: u32) -> Option<&[u8]>

fn len(&self) -> usize

fn is_empty(&self) -> bool

impl<I> ReaderSegments for [I]

where I: AsRef<[u8]>,

fn get_segment(&self, id: u32) -> Option<&[u8]>

fn len(&self) -> usize

fn is_empty(&self) -> bool

impl<S> ReaderSegments for &S

where S: ReaderSegments + ?Sized,

Allows stacking of references to a ReaderSegments.

This is especially useful with the implementation for slices, as it allows treating &[&[u8]] as ReaderSegments, e.g., to construct a Reader:

use capnp::message::Reader;
let slice_of_slices: &[&[u8]] = &[&*b"some data", &*b"more data"];
let _ = Reader::new(slice_of_slices, Default::default());

fn get_segment(&self, idx: u32) -> Option<&[u8]>

fn len(&self) -> usize

fn is_empty(&self) -> bool

Implementors

impl ReaderSegments for OutputSegments<'_>

impl ReaderSegments for OwnedSegments

Available on crate feature alloc only.

impl ReaderSegments for SegmentArray<'_>

impl<A> ReaderSegments for Builder<A>

where A: Allocator,

impl<T: AsRef<[u8]>> ReaderSegments for NoAllocBufferSegments<T>

impl<T: Deref<Target = [u8]>> ReaderSegments for BufferSegments<T>

Available on crate feature alloc only.