From 10da5553a8b4a166ea1f4c87a0058f971b13c5bc Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?S=C3=B6ren=20Meier?= Date: Sun, 28 Jul 2024 21:51:57 +0200 Subject: [PATCH] Replace `io::Cursor::{remaining_slice, is_empty}` with `io::Cursor::{split, split_mut}` --- library/std/src/io/cursor.rs | 65 +++++++++++++++++++----------------- library/std/src/io/tests.rs | 4 +-- 2 files changed, 37 insertions(+), 32 deletions(-) diff --git a/library/std/src/io/cursor.rs b/library/std/src/io/cursor.rs index 2ed64a40495ef..596022d62a52a 100644 --- a/library/std/src/io/cursor.rs +++ b/library/std/src/io/cursor.rs @@ -210,55 +210,60 @@ impl Cursor 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 Cursor +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]); /// - /// buff.set_position(2); - /// assert!(!buff.is_empty()); + /// assert_eq!(buff.split_mut(), ([].as_mut_slice(), [1, 2, 3, 4, 5].as_mut_slice())); /// - /// buff.set_position(5); - /// assert!(buff.is_empty()); + /// buff.set_position(2); + /// assert_eq!(buff.split_mut(), ([1, 2].as_mut_slice(), [3, 4, 5].as_mut_slice())); /// - /// 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 { - 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) -> io::Result { - 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 { 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; diff --git a/library/std/src/io/tests.rs b/library/std/src/io/tests.rs index a2c1c430863ab..22f13f4533e6f 100644 --- a/library/std/src/io/tests.rs +++ b/library/std/src/io/tests.rs @@ -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"); }