Struct byteio::Reader

pub struct Reader<'a, R: ReadBytes<'a>>(_, _, _);

A convenience structure used for counting the number of bytes read.

This structure wraps an implementation of ReadBytes. It forwards read operations to the inner type while also maintaining a count of the number of bytes that pass through it.

When you have finished with it, you can return the original type via the into_inner method.

When compiled with the std feature this structure implements Read.

Examples

use byteio::{ReadBytes, ReadBytesExt, Reader};

fn main() -> byteio::Result<()> {
    let buf: &[u8] = &[1, 0, 2, 0, 0, 0, 3];

    let mut reader = Reader::new(buf);

    assert_eq!(reader.try_read_u8()?, 1);
    assert_eq!(reader.try_read_u16_be()?, 2);
    assert_eq!(reader.try_read_u32_be()?, 3);

    assert_eq!(reader.num_bytes_read(), 7);

    let inner = reader.into_inner();
    assert!(inner.is_empty());

    Ok(())
}

Methods

impl<'a, R: ReadBytes<'a>> Reader<'a, R>

pub fn new(reader: R) -> Self

Creates a new Reader by wrapping a ReadBytes implementor.

Examples

use byteio::Reader;

let buf = [0_u8; 2];
let mut reader = Reader::new(&buf[..]);

pub fn num_bytes_read(&self) -> usize

Retrieves the number of bytes that have been read by this Reader.

Examples

use byteio::{ReadBytes, Reader};

let buf = [0_u8; 2];
let mut reader = Reader::new(&buf[..]);
let _ = reader.read_exact(1);
let _ = reader.read_exact(1);

assert_eq!(reader.num_bytes_read(), 2);

pub fn into_inner(self) -> R

Consumes this Reader and returns the original ReadBytes implementor.

Examples

use byteio::{ReadBytes, Reader};

let buf = [0_u8; 2];
let mut reader = Reader::new(&buf[..]);
let _ = reader.read_exact(1);
let inner = reader.into_inner();

assert_eq!(inner.len(), 1); // the reader consumed one byte from its view of the slice

Trait Implementations

impl<'a, R: ReadBytes<'a>> ReadBytes<'a> for Reader<'a, R>

fn read_exact(&mut self, n: usize) -> &'a [u8]

Forcibly attempts to read exactly n bytes from the buffer.

fn try_read_exact(&mut self, n: usize) -> Result<&'a [u8]>

Attempts to read exactly n bytes from the buffer.

impl<'a, R: PartialEq + ReadBytes<'a>> PartialEq<Reader<'a, R>> for Reader<'a, R>

fn eq(&self, other: &Reader<'a, R>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Reader<'a, R>) -> bool

This method tests for !=.

impl<'a, R: Eq + ReadBytes<'a>> Eq for Reader<'a, R>

impl<'a, R: Debug + ReadBytes<'a>> Debug for Reader<'a, R>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl<'a, R: ReadBytes<'a>> AsRef<[u8]> for Reader<'a, R>

fn as_ref(&self) -> &[u8]

Performs the conversion.

impl<'a, R: Clone + ReadBytes<'a>> Clone for Reader<'a, R>

Important traits for Reader<'a, R>

impl<'a, R: ReadBytes<'a>> Read for Reader<'a, R>

fn clone(&self) -> Reader<'a, R>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'a, R: ReadBytes<'a>> Read for Reader<'a, R>

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

unsafe fn initializer(&self) -> Initializer

🔬 This is a nightly-only experimental API. (read_initializer)

Determines if this Reader can work with buffers of uninitialized memory.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Read all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Read the exact number of bytes required to fill buf.

fn by_ref(&mut self) -> &mut Self

Creates a "by reference" adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an [Iterator] over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R> where
    R: Read, 

Creates an adaptor which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

Creates an adaptor which will read at most limit bytes from it.