Support gbkDecode for js

quickjs/src/main/java/com/fongmi/quickjs/method/Global.java

@@ -20,6 +20,7 @@ import com.whl.quickjs.wrapper.QuickJSContext;
 import java.io.IOException;
 import java.lang.reflect.Method;
 import java.net.URLEncoder;
+import java.nio.charset.CharacterCodingException;
 import java.util.Timer;
 import java.util.TimerTask;
 import java.util.concurrent.ExecutorService;
@@ -147,6 +148,14 @@ public class Global {
         return parser.joinUrl(parent, child);
     }
 
+    @Keep
+    @JSMethod
+    public String gbkDecode(JSArray buffer) throws CharacterCodingException {
+        String result = JSUtil.decodeTo("GB2312", buffer);
+        Logger.t("gbkDecode").d("text:%s\nresult:\n%s", buffer, result);
+        return result;
+    }
+
     @Keep
     @JSMethod
     public String md5X(String text) {

quickjs/src/main/java/com/fongmi/quickjs/utils/JSUtil.java

@@ -4,6 +4,9 @@ import com.whl.quickjs.wrapper.JSArray;
 import com.whl.quickjs.wrapper.JSObject;
 import com.whl.quickjs.wrapper.QuickJSContext;
 
+import java.nio.ByteBuffer;
+import java.nio.charset.CharacterCodingException;
+import java.nio.charset.Charset;
 import java.util.List;
 import java.util.Map;
 
@@ -29,4 +32,10 @@ public class JSUtil {
         for (String s : map.keySet()) obj.setProperty(s, map.get(s));
         return obj;
     }
+
+    public static String decodeTo(String charset, JSArray buffer) throws CharacterCodingException {
+        byte[] bytes = new byte[buffer.length()];
+        for (int i = 0; i < buffer.length(); i++) bytes[i] = (byte) (int) buffer.get(i);
+        return Charset.forName(charset).newDecoder().decode(ByteBuffer.wrap(bytes)).toString();
+    }
 }