[xiami] feat: implement xiami decipher

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
+    }
+}