mod lines;
mod read_line;
mod read_until;
mod split;
pub use lines::Lines;
pub use split::Split;
use read_line::ReadLineFuture;
use read_until::ReadUntilFuture;
use std::mem;
use std::pin::Pin;
use crate::io;
use crate::task::{Context, Poll};
pub use futures_io::AsyncBufRead as BufRead;
#[doc = r#"
Extension methods for [`BufRead`].
[`BufRead`]: ../trait.BufRead.html
"#]
pub trait BufReadExt: BufRead {
#[doc = r#"
Reads all bytes into `buf` until the delimiter `byte` or EOF is reached.
This function will read bytes from the underlying stream until the delimiter or EOF
is found. Once found, all bytes up to, and including, the delimiter (if found) will
be appended to `buf`.
If successful, this function will return the total number of bytes read.
# Examples
```no_run
# fn main() -> std::io::Result<()> { async_std::task::block_on(async {
#
use async_std::fs::File;
use async_std::io::BufReader;
use async_std::prelude::*;
let mut file = BufReader::new(File::open("a.txt").await?);
let mut buf = Vec::with_capacity(1024);
let n = file.read_until(b'\n', &mut buf).await?;
#
# Ok(()) }) }
```
Multiple successful calls to `read_until` append all bytes up to and including to
`buf`:
```
# fn main() -> std::io::Result<()> { async_std::task::block_on(async {
#
use async_std::io::BufReader;
use async_std::prelude::*;
let from: &[u8] = b"append\nexample\n";
let mut reader = BufReader::new(from);
let mut buf = vec![];
let mut size = reader.read_until(b'\n', &mut buf).await?;
assert_eq!(size, 7);
assert_eq!(buf, b"append\n");
size += reader.read_until(b'\n', &mut buf).await?;
assert_eq!(size, from.len());
assert_eq!(buf, from);
#
# Ok(()) }) }
```
"#]
fn read_until<'a>(
&'a mut self,
byte: u8,
buf: &'a mut Vec<u8>,
) -> ReadUntilFuture<'a, Self>
where
Self: Unpin,
{
ReadUntilFuture {
reader: self,
byte,
buf,
read: 0,
}
}
#[doc = r#"
Reads all bytes and appends them into `buf` until a newline (the 0xA byte) is
reached.
This function will read bytes from the underlying stream until the newline
delimiter (the 0xA byte) or EOF is found. Once found, all bytes up to, and
including, the delimiter (if found) will be appended to `buf`.
If successful, this function will return the total number of bytes read.
If this function returns `Ok(0)`, the stream has reached EOF.
# Errors
This function has the same error semantics as [`read_until`] and will also return
an error if the read bytes are not valid UTF-8. If an I/O error is encountered then
`buf` may contain some bytes already read in the event that all data read so far
was valid UTF-8.
[`read_until`]: #method.read_until
# Examples
```no_run
# fn main() -> std::io::Result<()> { async_std::task::block_on(async {
#
use async_std::fs::File;
use async_std::io::BufReader;
use async_std::prelude::*;
let mut file = BufReader::new(File::open("a.txt").await?);
let mut buf = String::new();
file.read_line(&mut buf).await?;
#
# Ok(()) }) }
```
"#]
fn read_line<'a>(
&'a mut self,
buf: &'a mut String,
) -> ReadLineFuture<'a, Self>
where
Self: Unpin,
{
ReadLineFuture {
reader: self,
bytes: unsafe { mem::replace(buf.as_mut_vec(), Vec::new()) },
buf,
read: 0,
}
}
#[doc = r#"
Returns a stream over the lines of this byte stream.
The stream returned from this function will yield instances of
[`io::Result`]`<`[`String`]`>`. Each string returned will *not* have a newline byte
(the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.
[`io::Result`]: type.Result.html
[`String`]: https://doc.rust-lang.org/std/string/struct.String.html
# Examples
```no_run
# fn main() -> std::io::Result<()> { async_std::task::block_on(async {
#
use async_std::fs::File;
use async_std::io::BufReader;
use async_std::prelude::*;
let file = File::open("a.txt").await?;
let mut lines = BufReader::new(file).lines();
let mut count = 0;
while let Some(line) = lines.next().await {
line?;
count += 1;
}
#
# Ok(()) }) }
```
"#]
fn lines(self) -> Lines<Self>
where
Self: Unpin + Sized,
{
Lines {
reader: self,
buf: String::new(),
bytes: Vec::new(),
read: 0,
}
}
#[doc = r#"
Returns a stream over the contents of this reader split on the byte `byte`.
The stream returned from this function will return instances of
[`io::Result`]`<`[`Vec<u8>`]`>`. Each vector returned will *not* have
the delimiter byte at the end.
This function will yield errors whenever [`read_until`] would have
also yielded an error.
[`io::Result`]: type.Result.html
[`Vec<u8>`]: ../vec/struct.Vec.html
[`read_until`]: #method.read_until
# Examples
[`std::io::Cursor`][`Cursor`] is a type that implements `BufRead`. In
this example, we use [`Cursor`] to iterate over all hyphen delimited
segments in a byte slice
[`Cursor`]: struct.Cursor.html
```
# fn main() -> std::io::Result<()> { async_std::task::block_on(async {
#
use async_std::prelude::*;
use async_std::io;
let cursor = io::Cursor::new(b"lorem-ipsum-dolor");
let mut split_iter = cursor.split(b'-').map(|l| l.unwrap());
assert_eq!(split_iter.next().await, Some(b"lorem".to_vec()));
assert_eq!(split_iter.next().await, Some(b"ipsum".to_vec()));
assert_eq!(split_iter.next().await, Some(b"dolor".to_vec()));
assert_eq!(split_iter.next().await, None);
#
# Ok(()) }) }
```
"#]
fn split(self, byte: u8) -> Split<Self>
where
Self: Sized,
{
Split {
reader: self,
buf: Vec::new(),
delim: byte,
read: 0,
}
}
}
impl<T: BufRead + ?Sized> BufReadExt for T {}
pub fn read_until_internal<R: BufReadExt + ?Sized>(
mut reader: Pin<&mut R>,
cx: &mut Context<'_>,
byte: u8,
buf: &mut Vec<u8>,
read: &mut usize,
) -> Poll<io::Result<usize>> {
loop {
let (done, used) = {
let available = futures_core::ready!(reader.as_mut().poll_fill_buf(cx))?;
if let Some(i) = memchr::memchr(byte, available) {
buf.extend_from_slice(&available[..=i]);
(true, i + 1)
} else {
buf.extend_from_slice(available);
(false, available.len())
}
};
reader.as_mut().consume(used);
*read += used;
if done || used == 0 {
return Poll::Ready(Ok(mem::replace(read, 0)));
}
}
}