bugfix for wrong buffer size for preDec

.gitignore

@@ -361,3 +361,11 @@ MigrationBackup/
 
 # Fody - auto-generated XML schema
 FodyWeavers.xsd
+
+# content from build
+npm/LICENSE.txt
+npm/QmcWasm.wasm
+npm/QmcLegacy.js
+npm/QmcWasm.js
+npm/QmcWasmBundle.js
+build/

README.md

@@ -25,6 +25,8 @@ const decrypted= (await DecryptKgmWasm(cipherText, extension)).data;
 
 ### 自行构建
 
+#### 依赖
+要自行构建此项目，请确保已经安装[Git]与[CMake]且其路径已经添加到 `PATH`
 #### Linux
 在此项目根目录中执行 `./build-wasm` 即可构建。构建结果将位于此项目根目录的npm子目录中。
 #### Windows
@@ -37,3 +39,5 @@ const decrypted= (await DecryptKgmWasm(cipherText, extension)).data;
 [授权协议]: https://github.com/nullptr-0/KgmWasm/blob/master/LICENSE.txt
 [kgm_wasm.ts]: https://github.com/nullptr-0/KgmWasm/blob/master/kgm_wasm.ts
 [GitHub Actions]: https://github.com/nullptr-0/KgmWasm/actions
+[Git]: https://git-scm.com/book/en/v2/Getting-Started-Installing-Git
+[CMake]: https://cmake.org/download/

build-wasm.cmd

@@ -11,6 +11,18 @@ if not exist build\emsdk (
   git clone https://github.com/emscripten-core/emsdk.git build\emsdk
 )
 
+rem Check for Ninja binary
+pushd build\wasm
+if not exist "ninja.exe" (
+  rem Install Ninja
+  curl -L https://github.com/ninja-build/ninja/releases/download/v1.11.1/ninja-win.zip -o ninja.zip
+  tar -xzvf ninja.zip
+  del ninja.zip
+)
+rem must setup PATH for ninja first to avoid conflict with emsdk_env.bat
+set PATH="%PATH%;%cd%"
+popd
+
 pushd build\emsdk
 rem git pull
 call emsdk.bat install 3.0.0
@@ -21,13 +33,6 @@ popd
 pushd build\wasm
 
 call emcmake cmake -DCMAKE_BUILD_TYPE=%BUILD_TYPE% ..\..
-rem Check if Ninja binary exists
-if not exist "ninja.exe" (
-  rem Install Ninja
-  curl -L https://github.com/ninja-build/ninja/releases/download/v1.11.1/ninja-win.zip -o ninja.zip
-  unzip ninja.zip
-  del ninja.zip
-)
 ninja.exe -f build.ninja -j 3
 
 set "TARGET_FILES=KgmLegacy.js KgmWasm.js KgmWasm.wasm KgmWasmBundle.js %CURR_DIR%\LICENSE.txt"

kgm_wasm.ts

@@ -2,7 +2,7 @@ import { KgmCrypto } from '@xhacker/kgmwasm/KgmWasmBundle';
 import KgmCryptoModule from '@xhacker/kgmwasm/KgmWasmBundle';
 import { MergeUint8Array } from '@/utils/MergeUint8Array';
 
-// 每次处理 2M 的数据
+// 每次可以处理 2M 的数据
 const DECRYPTION_BUF_SIZE = 2 *1024 * 1024;
 
 export interface KGMDecryptionResult {
@@ -36,12 +36,12 @@ export async function DecryptKgmWasm(kgmBlob: ArrayBuffer, ext: string): Promise
 
   // 申请内存块，并文件末端数据到 WASM 的内存堆
   let kgmBuf = new Uint8Array(kgmBlob);
-  const pQmcBuf = KgmCryptoObj._malloc(DECRYPTION_BUF_SIZE);
-  KgmCryptoObj.writeArrayToMemory(kgmBuf.slice(0, DECRYPTION_BUF_SIZE), pQmcBuf);
+  const pKgmBuf = KgmCryptoObj._malloc(DECRYPTION_BUF_SIZE);
+  const preDecDataSize = Math.min(DECRYPTION_BUF_SIZE, kgmBlob.byteLength); // 初始化缓冲区大小
+  KgmCryptoObj.writeArrayToMemory(kgmBuf.slice(0, preDecDataSize), pKgmBuf);
 
   // 进行解密初始化
-  const headerSize = KgmCryptoObj.preDec(pQmcBuf, DECRYPTION_BUF_SIZE, ext);
-  console.log(headerSize);
+  const headerSize = KgmCryptoObj.preDec(pKgmBuf, preDecDataSize, ext);
   kgmBuf = kgmBuf.slice(headerSize);
 
   const decryptedParts = [];
@@ -52,14 +52,14 @@ export async function DecryptKgmWasm(kgmBlob: ArrayBuffer, ext: string): Promise
 
     // 解密一些片段
     const blockData = new Uint8Array(kgmBuf.slice(offset, offset + blockSize));
-    KgmCryptoObj.writeArrayToMemory(blockData, pQmcBuf);
-    KgmCryptoObj.decBlob(pQmcBuf, blockSize, offset);
-    decryptedParts.push(KgmCryptoObj.HEAPU8.slice(pQmcBuf, pQmcBuf + blockSize));
+    KgmCryptoObj.writeArrayToMemory(blockData, pKgmBuf);
+    KgmCryptoObj.decBlob(pKgmBuf, blockSize, offset);
+    decryptedParts.push(KgmCryptoObj.HEAPU8.slice(pKgmBuf, pKgmBuf + blockSize));
 
     offset += blockSize;
     bytesToDecrypt -= blockSize;
   }
-  KgmCryptoObj._free(pQmcBuf);
+  KgmCryptoObj._free(pKgmBuf);
 
   result.data = MergeUint8Array(decryptedParts);
   result.success = true;

npm/package.json

@@ -8,7 +8,7 @@
   },
   "repository": {
     "type": "git",
-    "url": "git+https://github.com/xhacker-zzz/KgmWasm.git"
+    "url": "git+https://github.com/nullptr-0/KgmWasm.git"
   },
   "keywords": [
     "unlock-music",
@@ -18,7 +18,7 @@
   "author": "xhacker-zzz",
   "license": "Apache-2.0",
   "bugs": {
-    "url": "https://github.com/xhacker-zzz/KgmWasm/issues"
+    "url": "https://github.com/nullptr-0/KgmWasm/issues"
   },
-  "homepage": "https://github.com/xhacker-zzz/KgmWasm#readme"
+  "homepage": "https://github.com/nullptr-0/KgmWasm#readme"
 }