Initial support for BCP47 tags

- needs script/variant support
- currently only region(s) supported

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

@@ -256,8 +256,8 @@ public class ARSCDecoder {
         short mcc = mIn.readShort();
         short mnc = mIn.readShort();
 
-        char[] language = new char[] { (char) mIn.readByte(), (char) mIn.readByte() };
-        char[] country = new char[] { (char) mIn.readByte(), (char) mIn.readByte() };
+        char[] language = this.unpackLanguageOrRegion(mIn.readByte(), mIn.readByte(), 'a');
+        char[] country = this.unpackLanguageOrRegion(mIn.readByte(), mIn.readByte(), '0');
 
         byte orientation = mIn.readByte();
         byte touchscreen = mIn.readByte();
@@ -320,6 +320,24 @@ public class ARSCDecoder {
                 screenHeightDp, isInvalid);
     }
 
+    private char[] unpackLanguageOrRegion(byte in0, byte in1, char base) throws AndrolibException {
+        if (in0 == 0 && in1 == 0) {
+            return new char[] {(char) in0, (char) in1};
+        } else {
+            // check high bit, if so we have a packed 3 letter code
+            if (((in0 >> 7) & 1) == 1) {
+                int first = in1 & 0x1F;
+                int second = ((in1 & 0xE0) >> 5) + ((in0 & 0x03) << 3);
+                int third = (in0 & 0x7C) >> 2;
+
+                // since this function handles languages & regions, we add the value(s) to the base char
+                // which is usually 'a' or '0' depending on language or region.
+                return new char[] { (char) (first + base), (char) (second + base), (char) (third + base) };
+            }
+            return new char[] { (char) in0, (char) in1 };
+        }
+    }
+
     private void addMissingResSpecs() throws AndrolibException {
         int resId = mResId & 0xffff0000;
 

brut.apktool/apktool-lib/src/test/java/brut/androlib/BuildAndDecodeTest.java

@@ -182,6 +182,11 @@ public class BuildAndDecodeTest {
         compareValuesFiles("values-watch/strings.xml");
     }
 
+    @Test
+    public void bcp47tagTest() throws BrutException, IOException {
+        compareValuesFiles("values-ast-rES/strings.xml");
+    }
+
     @Test
     public void drawableNoDpiTest() throws BrutException, IOException {
         compareResFolder("drawable-nodpi");

brut.apktool/apktool-lib/src/test/resources/brut/apktool/testapp/res/values-ast-rES/strings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="test1">test1</string>
+</resources>