Crate rev_buf_reader

This 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 = "a\nb\nc";
let inner = io::Cursor::new(&data);
let reader = RevBufReader::new(inner);
let mut lines = reader.lines();

assert_eq!(lines.next().unwrap().unwrap(), "c".to_string());
assert_eq!(lines.next().unwrap().unwrap(), "b".to_string());
assert_eq!(lines.next().unwrap().unwrap(), "a".to_string());
assert!(lines.next().is_none());

Structs

RevBufReader

RevBufReader<R> is a struct similar to std::io::BufReader<R>, which adds buffering to any reader. But unlike BufReader<R>, RevBufReader<R> reads a data stream from the end to the start. The order of the bytes, however, remains the same. For example, when using RevBufReader<R> to read a text file, we can read the same lines as we would by using BufReader<R>, but starting from the last line until we get to the first one.