Struct Larry

pub struct Larry {
    pub file: File,
    /* private fields */
}

A Larry is a “line array”. It allows one to access a file as a lazily-read array of lines. This allows efficient random access to large files such as log files.

Fields

file: File

Implementations

impl Larry

pub fn new(path: &Path) -> Result<Larry, Error>

Constructs a new Larry.

Construction requires that the file be scanned for line-terminal byte sequences.

Examples

use larry::Larry;
use std::path::Path;

let mut larry = Larry::new(Path::new("production.log"))?;

Errors

Any std::io::Error arising while opening the file and scanning its contents for line endings will be returned.

pub fn get(&mut self, i: usize) -> Result<&str, Lerror>

Obtain a particular line.

Examples

use larry::Larry;
use std::path::Path;

let mut larry = Larry::new(Path::new("production.log"))?;
// print the last line of the file
let last_line_index = larry.len() - 1;
print!("{}", larry.get(last_line_index)?);

Errors

Index bound errors if you ask for a line beyond the end of the file and IO errors if the file has changed since the larry was created.

pub fn offset(&self, i: usize) -> Result<u64, Lerror>

Returns the byte offset of line i from the start of the file.

Examples

use larry::Larry;
use std::path::Path;

let larry = Larry::new(Path::new("production.log"))?;
// print the last line of the file
let last_line_index = larry.len() - 1;
print!("{}", larry.offset(last_line_index)?);

Errors

Index bound errors if you ask for a line beyond the end of the file

pub fn len(&self) -> usize

Returns number of lines.

Examples

use larry::Larry;
use std::path::Path;

let mut larry = Larry::new(Path::new("production.log"))?;
println!("number of lines line: {}", larry.len());