lib_um_crypto_rust/um_cli/src/cmd/qmc1.rs

use anyhow::Result;
use clap::Args;
use std::fs::File;
use std::io::{Read, Write};
use std::path::PathBuf;
use crate::Cli;

/// Decrypt a QMCv1 file
#[derive(Args)]
pub struct ArgsQMCv1 {
    /// Path to output file, e.g. /export/Music/song.flac
    #[clap(short, long)]
    output: PathBuf,

    /// Path to input file, e.g. /export/Music/song.qmcflac
    #[arg(name = "input")]
    input: PathBuf,
}

impl ArgsQMCv1 {
    pub fn run(&self, cli: &Cli) -> Result<i32> {
        let mut file_input = File::open(&self.input)?;
        let mut file_output = File::create(&self.output)?;

        let mut offset = 0usize;
        let mut buffer = vec![0u8; cli.buffer_size].into_boxed_slice();
        while let Ok(n) = file_input.read(&mut buffer) {
            if n == 0 {
                break;
            }

            umc_qmc::v1::decrypt(&mut buffer[..n], offset);
            file_output.write_all(&buffer[..n])?;
            offset += n;
        }

        Ok(0)
    }
}