TornaxO7 / rev_buf_reader

A struct similar to BufReader that reads a data stream in reverse order.

rev_buf_reader

This Rust crate provides a buffered reader capable of reading chunks of bytes of a data stream in reverse order. Its implementation is an adapted copy of BufReader from the nightly std::io.

Usage

Reading chunks of bytes in reverse order:

extern crate rev_buf_reader;

use rev_buf_reader::RevBufReader;
use std::io::{self, Read};

let data = [0, 1, 2, 3, 4, 5, 6, 7];
let inner = io::Cursor::new(&data);
let mut reader = RevBufReader::new(inner);

let mut buffer = [0, 0, 0];
assert_eq!(reader.read(&mut buffer).ok(), Some(3));
assert_eq!(buffer, [5, 6, 7]);

let mut buffer = [0, 0, 0, 0, 0];
assert_eq!(reader.read(&mut buffer).ok(), Some(5));
assert_eq!(buffer, [0, 1, 2, 3, 4]);

Reading text lines in reverse order:

extern crate rev_buf_reader;

use rev_buf_reader::RevBufReader;
use std::io::{self, BufRead};

let data = "This\nis\na sentence";
let inner = io::Cursor::new(&data);
let reader = RevBufReader::new(inner);
let mut lines = reader.lines();

assert_eq!(lines.next().unwrap().unwrap(), "a sentence".to_string());
assert_eq!(lines.next().unwrap().unwrap(), "is".to_string());
assert_eq!(lines.next().unwrap().unwrap(), "This".to_string());
assert!(lines.next().is_none());

Features

rev_buf_reader has one feature: read_initializer, which corresponds to an experimental feature of nightly Rust. If you use it in your project by adding #![feature(read_initializer)], you'll need to enable it for rev_buf_reader as well in your Cargo.toml.