From a3fbf9662bfc320c239f3460d5d34bcead11d2ac Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=B2=81=E6=A0=91=E4=BA=BA?= <lu.shuren@um-react.app>
Date: Wed, 18 Sep 2024 23:30:31 +0100
Subject: [PATCH] [xiami] feat: add xiami support

---
 src/decrypt-worker/Deciphers.ts           |  3 ++-
 src/decrypt-worker/decipher/XiamiMusic.ts | 28 +++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 src/decrypt-worker/decipher/XiamiMusic.ts

diff --git a/src/decrypt-worker/Deciphers.ts b/src/decrypt-worker/Deciphers.ts
index a98b6ac..5aef2b1 100644
--- a/src/decrypt-worker/Deciphers.ts
+++ b/src/decrypt-worker/Deciphers.ts
@@ -5,6 +5,7 @@ import { QQMusicV1Decipher, QQMusicV2Decipher } from '~/decrypt-worker/decipher/
 import { KuwoMusicDecipher } from '~/decrypt-worker/decipher/KuwoMusic.ts';
 import { KugouMusicDecipher } from '~/decrypt-worker/decipher/KugouMusic.ts';
 import { XimalayaAndroidDecipher, XimalayaPCDecipher } from '~/decrypt-worker/decipher/Ximalaya.ts';
+import { XiamiDecipher } from '~/decrypt-worker/decipher/XiamiMusic.ts';
 
 export enum Status {
   OK = 0,
@@ -51,7 +52,7 @@ export const allCryptoFactories: DecipherFactory[] = [
   XimalayaPCDecipher.make,
 
   // Xiami (*.xm)
-  // XiamiCrypto.make,
+  XiamiDecipher.make,
 
   /// File with a fixed footer goes second
 
diff --git a/src/decrypt-worker/decipher/XiamiMusic.ts b/src/decrypt-worker/decipher/XiamiMusic.ts
new file mode 100644
index 0000000..778d916
--- /dev/null
+++ b/src/decrypt-worker/decipher/XiamiMusic.ts
@@ -0,0 +1,28 @@
+import { DecipherInstance, DecipherOK, DecipherResult, Status } from '~/decrypt-worker/Deciphers.ts';
+import { Xiami } from '@unlock-music/crypto';
+import { chunkBuffer } from '~/decrypt-worker/util/buffer.ts';
+
+export class XiamiDecipher implements DecipherInstance {
+  cipherName = 'Xiami (XM)';
+
+  async decrypt(buffer: Uint8Array): Promise<DecipherResult | DecipherOK> {
+    const xm = Xiami.from_header(buffer.subarray(0, 0x10));
+    const { copyPlainLength } = xm;
+    const audioBuffer = buffer.slice(0x10);
+
+    for (const [block] of chunkBuffer(audioBuffer.subarray(copyPlainLength))) {
+      xm.decrypt(block);
+    }
+    xm.free();
+
+    return {
+      cipherName: this.cipherName,
+      status: Status.OK,
+      data: audioBuffer,
+    };
+  }
+
+  public static make() {
+    return new XiamiDecipher();
+  }
+}