thediff

A small Rust crate for calculating how different two files are, expressed as a percentage.
It is useful for file comparison, integrity checks, similarity analysis, or detecting changes between binary or text files.

Installation

Add the crate to your Cargo.toml:

[dependencies]
thediff = "0.1"

Usage

Compare Two Files

use std::path::Path;

use thediff::thediff;

fn main() -> std::io::Result<()> {
    let (diff_percent, same_percent) = thediff(Path::new("file1.bin"), Path::new("file2.bin"))?;
    println!(
        "Different part: {:.2}%, Same part: {:.2}%",
        diff_percent, same_percent
    );
    Ok(())
}

use std::path::Path;
use thediff::thediff_async;

#[tokio::main]
async fn main() -> std::io::Result<()> {
    let (diff_percent, same_percent) =
        thediff_async(
            Path::new("file1.bin"),
            Path::new("file2.bin"),
        )
        .await?;

    println!(
        "Different part: {:.2}%, Same part: {:.2}%",
        diff_percent, same_percent
    );

    Ok(())
}

How It Works

The crate compares files utf8 char by char:

• Counts how many chars differ
• Handles files of different sizes
• Extra bytes in the longer file are treated as differences

Examples