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use crate::BufMut;
use std::{cmp, io};
/// A `BufMut` adapter which implements `io::Write` for the inner value.
///
/// This struct is generally created by calling `writer()` on `BufMut`. See
/// documentation of [`writer()`](trait.BufMut.html#method.writer) for more
/// details.
#[derive(Debug)]
pub struct Writer<B> {
buf: B,
}
pub fn new<B>(buf: B) -> Writer<B> {
Writer { buf }
}
impl<B: BufMut> Writer<B> {
/// Gets a reference to the underlying `BufMut`.
///
/// It is inadvisable to directly write to the underlying `BufMut`.
///
/// # Examples
///
/// ```rust
/// use bytes::BufMut;
///
/// let buf = Vec::with_capacity(1024).writer();
///
/// assert_eq!(1024, buf.get_ref().capacity());
/// ```
pub fn get_ref(&self) -> &B {
&self.buf
}
/// Gets a mutable reference to the underlying `BufMut`.
///
/// It is inadvisable to directly write to the underlying `BufMut`.
///
/// # Examples
///
/// ```rust
/// use bytes::BufMut;
///
/// let mut buf = vec![].writer();
///
/// buf.get_mut().reserve(1024);
///
/// assert_eq!(1024, buf.get_ref().capacity());
/// ```
pub fn get_mut(&mut self) -> &mut B {
&mut self.buf
}
/// Consumes this `Writer`, returning the underlying value.
///
/// # Examples
///
/// ```rust
/// use bytes::BufMut;
/// use std::io;
///
/// let mut buf = vec![].writer();
/// let mut src = &b"hello world"[..];
///
/// io::copy(&mut src, &mut buf).unwrap();
///
/// let buf = buf.into_inner();
/// assert_eq!(*buf, b"hello world"[..]);
/// ```
pub fn into_inner(self) -> B {
self.buf
}
}
impl<B: BufMut + Sized> io::Write for Writer<B> {
fn write(&mut self, src: &[u8]) -> io::Result<usize> {
let n = cmp::min(self.buf.remaining_mut(), src.len());
self.buf.put(&src[0..n]);
Ok(n)
}
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
}