diskr-cli 1.0.0

Save your disk space, without fear of deleting the wrong thing.
Documentation 
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use anyhow::Result;
use std::fs::File;
use std::io::{Read, Seek, SeekFrom};
use std::path::Path;

const QUICK_HASH_BYTES: usize = 64 * 1024;

pub fn quick_hash(path: &Path) -> Result<blake3::Hash> {
    let mut f = File::open(path)?;
    let mut buf = vec![0u8; QUICK_HASH_BYTES];
    let n = f.read(&mut buf)?;
    Ok(blake3::hash(&buf[..n]))
}

pub fn full_hash(path: &Path) -> Result<blake3::Hash> {
    let mut f = File::open(path)?;
    let mut hasher = blake3::Hasher::new();
    std::io::copy(&mut f, &mut hasher)?;
    Ok(hasher.finalize())
}

pub fn bytes_equal(a: &Path, b: &Path) -> Result<bool> {
    const CHUNK: usize = 256 * 1024;
    let mut fa = File::open(a)?;
    let mut fb = File::open(b)?;
    fa.seek(SeekFrom::Start(0))?;
    fb.seek(SeekFrom::Start(0))?;
    let mut ba = vec![0u8; CHUNK];
    let mut bb = vec![0u8; CHUNK];
    loop {
        let na = fa.read(&mut ba)?;
        let nb = fb.read(&mut bb)?;
        if na != nb { return Ok(false); }
        if na == 0 { return Ok(true); }
        if ba[..na] != bb[..nb] { return Ok(false); }
    }
}