[xiami] feat: implement xiami decipher

.idea/lib_um_crypto.iml

@@ -13,6 +13,7 @@
       <sourceFolder url="file://$MODULE_DIR$/um_crypto/kgm/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/um_crypto/joox/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/um_crypto/xmly/src" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/um_crypto/xiami/src" isTestSource="false" />
       <excludeFolder url="file://$MODULE_DIR$/target" />
       <excludeFolder url="file://$MODULE_DIR$/um_wasm_loader/dist" />
       <excludeFolder url="file://$MODULE_DIR$/um_wasm_loader/pkg" />

Cargo.lock

@@ -528,6 +528,7 @@ dependencies = [
  "umc_ncm",
  "umc_qmc",
  "umc_utils",
+ "umc_xiami",
  "umc_xmly",
 ]
 
@@ -544,6 +545,7 @@ dependencies = [
  "umc_kuwo",
  "umc_ncm",
  "umc_qmc",
+ "umc_xiami",
  "umc_xmly",
  "wasm-bindgen",
  "wasm-bindgen-test",
@@ -623,6 +625,13 @@ dependencies = [
  "md-5",
 ]
 
+[[package]]
+name = "umc_xiami"
+version = "0.1.0"
+dependencies = [
+ "thiserror",
+]
+
 [[package]]
 name = "umc_xmly"
 version = "0.1.0"

um_cli/Cargo.toml

@@ -11,5 +11,6 @@ umc_kgm = { path = "../um_crypto/kgm" }
 umc_kuwo = { path = "../um_crypto/kuwo" }
 umc_ncm = { path = "../um_crypto/ncm" }
 umc_qmc = { path = "../um_crypto/qmc" }
+umc_xiami = { path = "../um_crypto/xiami" }
 umc_xmly = { path = "../um_crypto/xmly" }
 umc_utils = { path = "../um_crypto/utils" }

um_cli/src/cmd/mod.rs

@@ -5,6 +5,7 @@ pub mod kgm;
 pub mod ncm;
 pub mod qmc1;
 pub mod qmc2;
+pub mod xiami;
 pub mod xmly;
 
 #[derive(Subcommand)]
@@ -21,4 +22,6 @@ pub enum Commands {
     JOOX(joox::ArgsJoox),
     #[command(name = "xmly")]
     XMLY(xmly::ArgsXimalaya),
+    #[command(name = "xiami")]
+    Xiami(xiami::ArgsXiami),
 }

um_cli/src/cmd/xiami.rs

@@ -0,0 +1,44 @@
+use crate::Cli;
+use anyhow::Result;
+use clap::Args;
+use std::fs::File;
+use std::io;
+use std::io::{BufReader, BufWriter, Read, Write};
+use std::path::PathBuf;
+
+/// Decrypt a XM file (Xiami)
+#[derive(Args)]
+pub struct ArgsXiami {
+    /// Path to output file, e.g. /export/Music/song.flac
+    #[clap(short, long)]
+    output: PathBuf,
+
+    /// Path to input file, e.g. /export/Music/song.xm
+    #[arg(name = "input")]
+    input: PathBuf,
+}
+
+impl ArgsXiami {
+    pub fn run(&self, cli: &Cli) -> Result<i32> {
+        let mut reader = BufReader::with_capacity(cli.buffer_size, File::open(&self.input)?);
+        let mut writer = BufWriter::with_capacity(cli.buffer_size, File::create(&self.output)?);
+
+        let mut header = [0u8; 0x10];
+        reader.read_exact(&mut header)?;
+        let xm = umc_xiami::XiamiFile::from_header(&header)?;
+        let mut copy_reader = (&mut reader).take(xm.copy_len as u64);
+        io::copy(&mut copy_reader, &mut writer)?;
+
+        let mut buffer = vec![0u8; cli.buffer_size];
+        loop {
+            let n = reader.read(&mut buffer[..])?;
+            if n == 0 {
+                break;
+            }
+            xm.decrypt(&mut buffer[..n]);
+            writer.write_all(&buffer[..n])?;
+        }
+
+        Ok(0)
+    }
+}

um_cli/src/main.rs

@@ -33,6 +33,7 @@ fn run_command(cli: &Cli) -> Result<i32> {
         Some(Commands::KGM(cmd)) => cmd.run(&cli),
         Some(Commands::JOOX(cmd)) => cmd.run(&cli),
         Some(Commands::XMLY(cmd)) => cmd.run(&cli),
+        Some(Commands::Xiami(cmd)) => cmd.run(&cli),
         None => {
             // https://github.com/clap-rs/clap/issues/3857#issuecomment-1161796261
             todo!("implement a sensible default command, similar to um/cli");

um_crypto/xiami/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "umc_xiami"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+thiserror = "1.0.63"

um_crypto/xiami/src/lib.rs

@@ -0,0 +1,45 @@
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum XiamiError {
+    #[error("header too small, require at least {0} bytes")]
+    HeaderTooSmall(usize),
+
+    #[error("not a xiami file")]
+    NotXiamiFile,
+}
+
+pub struct XiamiFile {
+    pub copy_len: usize,
+    pub format: [u8; 4],
+    key: u8,
+}
+
+impl XiamiFile {
+    pub fn from_header(buffer: &[u8]) -> Result<Self, XiamiError> {
+        if buffer.len() < 0x10 {
+            Err(XiamiError::HeaderTooSmall(0x10))?;
+        }
+
+        let (format, copy_len, key) = match buffer[..0x10] {
+            [b'i', b'f', b'm', b't', f1, f2, f3, f4, 0xfe, 0xfe, 0xfe, 0xfe, a, b, c, key] => {
+                let copy_len = (a as usize) | ((b as usize) << 8) | ((c as usize) << 16);
+                let format = [f1, f2, f3, f4];
+                (format, copy_len, key.wrapping_sub(1))
+            }
+            _ => Err(XiamiError::NotXiamiFile)?,
+        };
+
+        Ok(Self {
+            copy_len,
+            format,
+            key,
+        })
+    }
+
+    pub fn decrypt(&self, buffer: &mut [u8]) {
+        for b in buffer.iter_mut() {
+            *b = self.key.wrapping_sub(*b);
+        }
+    }
+}

um_wasm/Cargo.toml

@@ -28,6 +28,7 @@ umc_kgm = { path = "../um_crypto/kgm" }
 umc_kuwo = { path = "../um_crypto/kuwo" }
 umc_ncm = { path = "../um_crypto/ncm" }
 umc_qmc = { path = "../um_crypto/qmc" }
+umc_xiami = { path = "../um_crypto/xiami" }
 umc_xmly = { path = "../um_crypto/xmly" }
 um_audio = { path = "../um_audio" }
 

um_wasm/src/exports/mod.rs

@@ -4,4 +4,5 @@ pub mod kgm;
 pub mod kuwo;
 pub mod ncm;
 pub mod qmc;
+mod xiami;
 pub mod xmly;

um_wasm/src/exports/xiami.rs

@@ -0,0 +1,27 @@
+use umc_xiami::XiamiFile;
+use wasm_bindgen::prelude::wasm_bindgen;
+use wasm_bindgen::JsError;
+
+/// Xiami XM file decipher.
+#[wasm_bindgen(js_name=Xiami)]
+pub struct JsXiami(XiamiFile);
+
+#[wasm_bindgen(js_class = Xiami)]
+impl JsXiami {
+    /// Parse the Xiami header (0x400 bytes)
+    pub fn from_header(header: &[u8]) -> Result<JsXiami, JsError> {
+        let hdr = XiamiFile::from_header(header)?;
+        Ok(JsXiami(hdr))
+    }
+
+    /// Decrypt encrypted buffer part.
+    pub fn decrypt(&self, buffer: &mut [u8]) {
+        self.0.decrypt(buffer)
+    }
+
+    /// After header (0x10 bytes), the number of bytes should be copied without decryption.
+    #[wasm_bindgen(getter, js_name=copyPlainLength)]
+    pub fn get_copy_plain_length(&self) -> usize {
+        self.0.copy_len
+    }
+}