Fixes issue with decoding apk containing a zero byte 9patch

brut.apktool/apktool-lib/src/main/java/brut/androlib/res/decoder/Res9patchStreamDecoder.java

@@ -38,6 +38,10 @@ public class Res9patchStreamDecoder implements ResStreamDecoder {
         try {
             byte[] data = IOUtils.toByteArray(in);
 
+            if (data.length == 0) {
+                return;
+            }
+
             BufferedImage im = ImageIO.read(new ByteArrayInputStream(data));
             int w = im.getWidth(), h = im.getHeight();
 

brut.apktool/apktool-lib/src/test/java/brut/androlib/decode/Empty9PatchTest.java

@@ -0,0 +1,63 @@
+/**
+ *  Copyright (C) 2019 Ryszard Wiśniewski <brut.alll@gmail.com>
+ *  Copyright (C) 2019 Connor Tumbleson <connor.tumbleson@gmail.com>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package brut.androlib.decode;
+
+import brut.androlib.ApkDecoder;
+import brut.androlib.BaseTest;
+import brut.androlib.TestUtils;
+import brut.common.BrutException;
+import brut.directory.ExtFile;
+import brut.util.OS;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.IOException;
+
+import static org.junit.Assert.assertTrue;
+
+public class Empty9PatchTest extends BaseTest {
+
+    @BeforeClass
+    public static void beforeClass() throws Exception {
+        TestUtils.cleanFrameworkFile();
+        sTmpDir = new ExtFile(OS.createTempDirectory());
+        TestUtils.copyResourceDir(Empty9PatchTest.class, "decode/empty9patch/", sTmpDir);
+    }
+
+    @AfterClass
+    public static void afterClass() throws BrutException {
+        OS.rmdir(sTmpDir);
+    }
+
+    @Test
+    public void decodeWithEmpty9PatchFile() throws BrutException, IOException {
+        String apk = "empty9patch.apk";
+
+        // decode empty9patch.apk
+        ApkDecoder apkDecoder = new ApkDecoder(new File(sTmpDir + File.separator + apk));
+        sTestOrigDir = new ExtFile(sTmpDir + File.separator + apk + ".out");
+
+        apkDecoder.setOutDir(new File(sTmpDir + File.separator + apk + ".out"));
+        apkDecoder.decode();
+
+        File aPng =  new File(sTestOrigDir,"res/drawable-xhdpi/empty.9.png");
+        assertTrue(aPng.isFile());
+        assertTrue(aPng.length() == 0);
+    }
+}