qubit_io/traits/
buf_read_seek.rs

1// =============================================================================
2//    Copyright (c) 2026 Haixing Hu.
3//
4//    SPDX-License-Identifier: Apache-2.0
5//
6//    Licensed under the Apache License, Version 2.0.
7// =============================================================================
8use std::io::{
9    BufRead,
10    Seek,
11};
12
13/// Object-safe capability trait for values that can be buffered-read and
14/// repositioned.
15///
16/// `BufReadSeek` gives the common [`BufRead`] + [`Seek`] combination a named
17/// trait for APIs that need buffered reads and random access through trait
18/// objects. Typical use cases include line-oriented parsers over seekable files
19/// and buffered readers that still need to jump between sections.
20///
21/// The trait adds no methods of its own. All operations come from the
22/// standard-library supertraits, and every type implementing both [`BufRead`]
23/// and [`Seek`] automatically implements `BufReadSeek`.
24///
25/// # Examples
26///
27/// ```rust
28/// use qubit_io::BufReadSeek;
29/// use std::io::{BufRead, BufReader, Cursor, SeekFrom};
30///
31/// fn read_after_prefix(input: &mut dyn BufReadSeek) -> std::io::Result<String> {
32///     input.seek(SeekFrom::Start(4))?;
33///
34///     let mut line = String::new();
35///     input.read_line(&mut line)?;
36///     Ok(line)
37/// }
38///
39/// let cursor = Cursor::new(b"abc\ndef".to_vec());
40/// let mut reader = BufReader::new(cursor);
41/// assert_eq!(read_after_prefix(&mut reader)?, "def");
42/// # Ok::<(), std::io::Error>(())
43/// ```
44pub trait BufReadSeek: BufRead + Seek {}
45
46impl<T> BufReadSeek for T where T: BufRead + Seek + ?Sized {}
qubit_io/traits/buf_read_seek.rs

qubit_io/traits/
buf_read_seek.rs
