[wasm] feat: export ncm

um_wasm/src/exports/mod.rs

@@ -1,2 +1,3 @@
 pub mod kuwo;
+pub mod ncm;
 pub mod qmc;

um_wasm/src/exports/ncm.rs

@@ -0,0 +1,62 @@
+use umc_ncm::header::NCMFile;
+use umc_ncm::NetEaseCryptoError;
+use wasm_bindgen::prelude::wasm_bindgen;
+use wasm_bindgen::JsError;
+
+/// QMC Footer.
+#[wasm_bindgen(js_name=NCMFile)]
+pub struct JsNCMFile {
+    ncm: Option<NCMFile>,
+}
+
+#[wasm_bindgen(js_class=NCMFile)]
+impl JsNCMFile {
+    /// Open NCM file.
+    /// If everything is ok, return `0`.
+    ///
+    /// # Arguments
+    ///
+    /// * `header`: Header bytes of NCM file.
+    ///
+    /// returns: Result<usize, JsError>
+    ///
+    /// If it needs more bytes, the new header size will be returned.
+    /// If the header was large enough, it will return 0.
+    pub fn open(&mut self, header: &[u8]) -> Result<usize, JsError> {
+        match NCMFile::new(header) {
+            Ok(ncm) => {
+                self.ncm = Some(ncm);
+                Ok(0)
+            }
+            Err(NetEaseCryptoError::HeaderTooSmall(n)) => Ok(n),
+            Err(err) => Err(JsError::new(err.to_string().as_str())),
+        }
+    }
+
+    /// Decrypt buffer.
+    ///
+    /// # Arguments
+    ///
+    /// * `buffer`: Buffer to decrypt.
+    /// * `offset`: Offset (start from 0, of encrypted binary data)
+    ///
+    /// returns: Result<(), JsError>
+    pub fn decrypt(&self, buffer: &mut [u8], offset: usize) -> Result<(), JsError> {
+        if let Some(ncm) = &self.ncm {
+            ncm.decrypt(buffer, offset);
+            Ok(())
+        } else {
+            Err(JsError::new("NCMFile not initialized."))
+        }
+    }
+
+    /// Get audio data offset.
+    #[wasm_bindgen(getter, js_name=audioOffset)]
+    pub fn get_audio_offset(&self) -> Result<usize, JsError> {
+        if let Some(ncm) = &self.ncm {
+            Ok(ncm.audio_data_offset)
+        } else {
+            Err(JsError::new("NCMFile not initialized."))
+        }
+    }
+}