feat: add experimental cli

um_cli/src/cmd/mod.rs

@@ -0,0 +1,9 @@
+use clap::Subcommand;
+
+pub mod qmc1;
+
+#[derive(Subcommand)]
+pub enum Commands {
+    #[command(name = "qmc1")]
+    QMCv1(qmc1::ArgsQMCv1),
+}

um_cli/src/cmd/qmc1.rs

@@ -0,0 +1,41 @@
+use anyhow::Result;
+use clap::Args;
+use std::fs::File;
+use std::io::{Read, Write};
+use std::path::PathBuf;
+
+/// 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,
+}
+
+// 4MiB buffer is working well on my machine.
+const BUFFER_SIZE: usize = 4 * 1024 * 1024;
+
+impl ArgsQMCv1 {
+    pub fn run(&self) -> 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; 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)
+    }
+}