millennium-utils 1.0.0-beta.3

// Copyright 2022 pyke.io
//           2019-2021 Tauri Programme within The Commons Conservancy
//                     [https://tauri.studio/]
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! IO helpers.

use std::io::BufRead;

/// Read a line breaking in both \n and \r.
///
/// Adapted from <https://doc.rust-lang.org/std/io/trait.BufRead.html#method.read_line>.
pub fn read_line<R: BufRead + ?Sized>(r: &mut R, buf: &mut Vec<u8>) -> std::io::Result<usize> {
	let mut read = 0;
	loop {
		let (done, used) = {
			let available = match r.fill_buf() {
				Ok(n) => n,
				Err(ref e) if e.kind() == std::io::ErrorKind::Interrupted => continue,
				Err(e) => return Err(e)
			};
			match memchr::memchr(b'\n', available) {
				Some(i) => {
					let end = i + 1;
					buf.extend_from_slice(&available[..end]);
					(true, end)
				}
				None => match memchr::memchr(b'\r', available) {
					Some(i) => {
						let end = i + 1;
						buf.extend_from_slice(&available[..end]);
						(true, end)
					}
					None => {
						buf.extend_from_slice(available);
						(false, available.len())
					}
				}
			}
		};
		r.consume(used);
		read += used;
		if done || used == 0 {
			if buf.ends_with(&[b'\n']) {
				buf.pop();
			}
			return Ok(read);
		}
	}
}