Struct Writer

pub struct Writer<W: WriteBytes>(/* private fields */);

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

This structure wraps an implementation of WriteBytes. It forwards write 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 Write.

Examples

use byteio::{WriteBytes, WriteBytesExt, Writer};

fn main() -> byteio::Result<()> {
    let mut buf = [0; 7];

    {
        let mut writer = Writer::new(&mut buf[..]);

        writer.try_write_u8(1)?;
        writer.try_write_u16_be(2)?;
        writer.try_write_u32_be(3)?;

        assert_eq!(writer.num_bytes_written(), 7);

        let inner = writer.into_inner();
        assert!(inner.is_empty());
    }

    assert_eq!(buf, [1, 0, 2, 0, 0, 0, 3]);

    Ok(())
}

Implementations

impl<W: WriteBytes> Writer<W>

pub fn new(writer: W) -> Self

Creates a new Writer by wrapping a WriteBytes implementor.

Examples

use byteio::Writer;

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

pub fn num_bytes_written(&self) -> usize

Retrieves the number of bytes that have been written by this Writer.

Examples

use byteio::{WriteBytes, Writer};

let mut buf = [0_u8; 2];
let mut writer = Writer::new(&mut buf[..]);
writer.write_exact(&[1]);
writer.write_exact(&[1]);

assert_eq!(writer.num_bytes_written(), 2);

pub fn into_inner(self) -> W

Consumes this Writer and returns the original WriteBytes implementor.

use byteio::{WriteBytes, Writer};

let mut buf = [0_u8; 2];
let mut writer = Writer::new(&mut buf[..]);
writer.write_exact(&[1]);
let inner = writer.into_inner();

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

Trait Implementations

impl<W: WriteBytes> AsMut<[u8]> for Writer<W>

fn as_mut(&mut self) -> &mut [u8]

Converts this type into a mutable reference of the (usually inferred) input type.

impl<W: Clone + WriteBytes> Clone for Writer<W>

fn clone(&self) -> Writer<W>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<W: Debug + WriteBytes> Debug for Writer<W>

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

Formats the value using the given formatter.

impl<W: Hash + WriteBytes> Hash for Writer<W>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<W: PartialEq + WriteBytes> PartialEq for Writer<W>

fn eq(&self, other: &Writer<W>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<W: WriteBytes> Write for Writer<W>

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

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

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

Determines if this Writer has an efficient write_vectored implementation.

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

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

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

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

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

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.

impl<W: WriteBytes> WriteBytes for Writer<W>

fn write_exact(&mut self, buf: &[u8])

Forcibly attempts to write the exact slice into the buffer.

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

Attempts to write the exact slice into the buffer.

impl<W: Eq + WriteBytes> Eq for Writer<W>

impl<W: WriteBytes> StructuralPartialEq for Writer<W>