Crate byteseeker

This library provides the ByteSeeker type to seek the occurences of a given byte slice (&[u8]) from either end of a stream of bytes.

The ByteSeeker is helpful if you want to check the presences of a certain byte slice, or you want to read partial of contents when you know where to start.

Examples

• Read the last line of a file, without loading the entire file into memory.

use byteseeker::{ByteSeeker, Result};
use std::io::{Read, Seek, SeekFrom};
use std::fs::File;

fn read_last_line(f: &mut File, buf: &mut Vec<u8>) -> Result<()> {
    let mut seeker = ByteSeeker::new(f);
    let pos = seeker.seek_back(b"\n")?;
    let starting = if pos == seeker.len() - 1 {
        // if file ends with a newline.
        seeker.seek_back(b"\n")? + 1
    } else {
        // if file doesn't end with a newline.
        pos + 1
    };

    f.seek(SeekFrom::Start(starting as u64))?;
    f.read_to_end(buf)?;
    Ok(())
}

fn main() -> Result<()> {
   let mut f = File::open("./data.csv")?;
   let mut buf = Vec::new();
   read_last_line(&mut f, &mut buf)?;

   // For simplicity, we just assume the given file is UTF-8 valid and unwrap the result here.
   println!("{}", std::str::from_utf8(&buf).unwrap());

   Ok(())
}

Structs

ByteSeeker	Seeker that can seek the occurences of a given byte slice within a stream of bytes.
Error	An error that can occur when seeking bytes.

Enums

ErrorKind

The specific type of an error.

Type Definitions

Result

A type alias for Result<T, byteSeeker::Error>.