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Replace io::Cursor::{remaining_slice, is_empty} with io::Cursor::{split, split_mut}

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This commit is contained in:
Sören Meier 2024-07-28 21:51:57 +02:00
parent 3954398882
commit 10da5553a8
2 changed files with 37 additions and 32 deletions
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65
library/std/src/io/cursor.rs
View File

@ -210,55 +210,60 @@ impl<T> Cursor<T>
where
T: AsRef<[u8]>,
{
/// Returns the remaining slice.
/// Splits the underlying slice at the cursor position and returns them.
///
/// # Examples
///
/// ```
/// #![feature(cursor_remaining)]
/// #![feature(cursor_split)]
/// use std::io::Cursor;
///
/// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
///
/// assert_eq!(buff.remaining_slice(), &[1, 2, 3, 4, 5]);
/// assert_eq!(buff.split(), ([].as_slice(), [1, 2, 3, 4, 5].as_slice()));
///
/// buff.set_position(2);
/// assert_eq!(buff.remaining_slice(), &[3, 4, 5]);
///
/// buff.set_position(4);
/// assert_eq!(buff.remaining_slice(), &[5]);
/// assert_eq!(buff.split(), ([1, 2].as_slice(), [3, 4, 5].as_slice()));
///
/// buff.set_position(6);
/// assert_eq!(buff.remaining_slice(), &[]);
/// assert_eq!(buff.split(), ([1, 2, 3, 4, 5].as_slice(), [].as_slice()));
/// ```
#[unstable(feature = "cursor_remaining", issue = "86369")]
pub fn remaining_slice(&self) -> &[u8] {
let len = self.pos.min(self.inner.as_ref().len() as u64);
&self.inner.as_ref()[(len as usize)..]
#[unstable(feature = "cursor_split", issue = "86369")]
pub fn split(&self) -> (&[u8], &[u8]) {
let slice = self.inner.as_ref();
let pos = self.pos.min(slice.len() as u64);
slice.split_at(pos as usize)
}
}
/// Returns `true` if the remaining slice is empty.
impl<T> Cursor<T>
where
T: AsMut<[u8]>,
{
/// Splits the underlying slice at the cursor position and returns them
/// mutably.
///
/// # Examples
///
/// ```
/// #![feature(cursor_remaining)]
/// #![feature(cursor_split)]
/// use std::io::Cursor;
///
/// let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);
///
/// assert_eq!(buff.split_mut(), ([].as_mut_slice(), [1, 2, 3, 4, 5].as_mut_slice()));
///
/// buff.set_position(2);
/// assert!(!buff.is_empty());
/// assert_eq!(buff.split_mut(), ([1, 2].as_mut_slice(), [3, 4, 5].as_mut_slice()));
///
/// buff.set_position(5);
/// assert!(buff.is_empty());
///
/// buff.set_position(10);
/// assert!(buff.is_empty());
/// buff.set_position(6);
/// assert_eq!(buff.split_mut(), ([1, 2, 3, 4, 5].as_mut_slice(), [].as_mut_slice()));
/// ```
#[unstable(feature = "cursor_remaining", issue = "86369")]
pub fn is_empty(&self) -> bool {
self.pos >= self.inner.as_ref().len() as u64
#[unstable(feature = "cursor_split", issue = "86369")]
pub fn split_mut(&mut self) -> (&mut [u8], &mut [u8]) {
let slice = self.inner.as_mut();
let pos = self.pos.min(slice.len() as u64);
slice.split_at_mut(pos as usize)
}
}
@ -320,7 +325,7 @@ where
T: AsRef<[u8]>,
{
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let n = Read::read(&mut self.remaining_slice(), buf)?;
let n = Read::read(&mut Cursor::split(self).1, buf)?;
self.pos += n as u64;
Ok(n)
}
@ -328,7 +333,7 @@ where
fn read_buf(&mut self, mut cursor: BorrowedCursor<'_>) -> io::Result<()> {
let prev_written = cursor.written();
Read::read_buf(&mut self.remaining_slice(), cursor.reborrow())?;
Read::read_buf(&mut Cursor::split(self).1, cursor.reborrow())?;
self.pos += (cursor.written() - prev_written) as u64;
@ -352,7 +357,7 @@ where
}
fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
let result = Read::read_exact(&mut self.remaining_slice(), buf);
let result = Read::read_exact(&mut Cursor::split(self).1, buf);
match result {
Ok(_) => self.pos += buf.len() as u64,
@ -366,14 +371,14 @@ where
fn read_buf_exact(&mut self, mut cursor: BorrowedCursor<'_>) -> io::Result<()> {
let prev_written = cursor.written();
let result = Read::read_buf_exact(&mut self.remaining_slice(), cursor.reborrow());
let result = Read::read_buf_exact(&mut Cursor::split(self).1, cursor.reborrow());
self.pos += (cursor.written() - prev_written) as u64;
result
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
let content = self.remaining_slice();
let content = Cursor::split(self).1;
let len = content.len();
buf.try_reserve(len)?;
buf.extend_from_slice(content);
@ -384,7 +389,7 @@ where
fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
let content =
crate::str::from_utf8(self.remaining_slice()).map_err(|_| io::Error::INVALID_UTF8)?;
crate::str::from_utf8(Cursor::split(self).1).map_err(|_| io::Error::INVALID_UTF8)?;
let len = content.len();
buf.try_reserve(len)?;
buf.push_str(content);
@ -400,7 +405,7 @@ where
T: AsRef<[u8]>,
{
fn fill_buf(&mut self) -> io::Result<&[u8]> {
Ok(self.remaining_slice())
Ok(Cursor::split(self).1)
}
fn consume(&mut self, amt: usize) {
self.pos += amt as u64;

4
library/std/src/io/tests.rs
View File

@ -675,13 +675,13 @@ fn cursor_read_exact_eof() {
let mut r = slice.clone();
assert!(r.read_exact(&mut [0; 10]).is_err());
assert!(r.is_empty());
assert!(Cursor::split(&r).1.is_empty());
let mut r = slice;
let buf = &mut [0; 10];
let mut buf = BorrowedBuf::from(buf.as_mut_slice());
assert!(r.read_buf_exact(buf.unfilled()).is_err());
assert!(r.is_empty());
assert!(Cursor::split(&r).1.is_empty());
assert_eq!(buf.filled(), b"123456");
}