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use {Buf}; use std::{cmp, io}; /// A `Buf` adapter which implements `io::Read` for the inner value. /// /// This struct is generally created by calling `reader()` on `Buf`. See /// documentation of [`reader()`](trait.Buf.html#method.reader) for more /// details. #[derive(Debug)] pub struct Reader<B> { buf: B, } pub fn new<B>(buf: B) -> Reader<B> { Reader { buf: buf } } impl<B: Buf> Reader<B> { /// Gets a reference to the underlying `Buf`. /// /// It is inadvisable to directly read from the underlying `Buf`. /// /// # Examples /// /// ```rust /// use bytes::Buf; /// use std::io::{self, Cursor}; /// /// let mut buf = Cursor::new(b"hello world").reader(); /// /// assert_eq!(0, buf.get_ref().position()); /// ``` pub fn get_ref(&self) -> &B { &self.buf } /// Gets a mutable reference to the underlying `Buf`. /// /// It is inadvisable to directly read from the underlying `Buf`. /// /// # Examples /// /// ```rust /// use bytes::Buf; /// use std::io::{self, Cursor}; /// /// let mut buf = Cursor::new(b"hello world").reader(); /// let mut dst = vec![]; /// /// buf.get_mut().set_position(2); /// io::copy(&mut buf, &mut dst).unwrap(); /// /// assert_eq!(*dst, b"llo world"[..]); /// ``` pub fn get_mut(&mut self) -> &mut B { &mut self.buf } /// Consumes this `Reader`, returning the underlying value. /// /// # Examples /// /// ```rust /// use bytes::Buf; /// use std::io::{self, Cursor}; /// /// let mut buf = Cursor::new(b"hello world").reader(); /// let mut dst = vec![]; /// /// io::copy(&mut buf, &mut dst).unwrap(); /// /// let buf = buf.into_inner(); /// assert_eq!(0, buf.remaining()); /// ``` pub fn into_inner(self) -> B { self.buf } } impl<B: Buf + Sized> io::Read for Reader<B> { fn read(&mut self, dst: &mut [u8]) -> io::Result<usize> { let len = cmp::min(self.buf.remaining(), dst.len()); Buf::copy_to_slice(&mut self.buf, &mut dst[0..len]); Ok(len) } }