| use std::fmt; |
| use std::pin::Pin; |
| |
| use crate::io::{self, Read}; |
| use crate::task::{Context, Poll}; |
| |
| /// Creates an instance of a reader that infinitely repeats one byte. |
| /// |
| /// All reads from this reader will succeed by filling the specified buffer with the given byte. |
| /// |
| /// ## Examples |
| /// |
| /// ```rust |
| /// # fn main() -> std::io::Result<()> { async_std::task::block_on(async { |
| /// # |
| /// use async_std::io; |
| /// use async_std::prelude::*; |
| /// |
| /// let mut buffer = [0; 3]; |
| /// io::repeat(0b101).read_exact(&mut buffer).await?; |
| /// |
| /// assert_eq!(buffer, [0b101, 0b101, 0b101]); |
| /// # |
| /// # Ok(()) }) } |
| /// ``` |
| pub fn repeat(byte: u8) -> Repeat { |
| Repeat { byte } |
| } |
| |
| /// A reader which yields one byte over and over and over and over and over and... |
| /// |
| /// This reader is created by the [`repeat`] function. See its |
| /// documentation for more. |
| /// |
| /// [`repeat`]: fn.repeat.html |
| pub struct Repeat { |
| byte: u8, |
| } |
| |
| impl fmt::Debug for Repeat { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| f.pad("Empty { .. }") |
| } |
| } |
| |
| impl Read for Repeat { |
| #[inline] |
| fn poll_read( |
| self: Pin<&mut Self>, |
| _: &mut Context<'_>, |
| buf: &mut [u8], |
| ) -> Poll<io::Result<usize>> { |
| for b in &mut *buf { |
| *b = self.byte; |
| } |
| Poll::Ready(Ok(buf.len())) |
| } |
| } |