diff --git a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBackedClassDef.java b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBackedClassDef.java
index e5924765..4a73f345 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBackedClassDef.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBackedClassDef.java
@@ -69,9 +69,9 @@ public class DexBackedClassDef implements ClassDef {
 
         this.name = dexBuf.getType(dexBuf.readSmallUint(classDefOffset));
         this.accessFlags = dexBuf.readSmallUint(classDefOffset + ACCESS_FLAGS_OFFSET);
-        this.superclass = dexBuf.getOptionalString(dexBuf.readSmallUint(classDefOffset + SUPERCLASS_OFFSET));
+        this.superclass = dexBuf.getOptionalString(dexBuf.readOptionalUint(classDefOffset + SUPERCLASS_OFFSET));
         this.interfacesOffset = dexBuf.readSmallUint(classDefOffset + INTERFACES_OFFSET);
-        this.sourceFile = dexBuf.getOptionalString(dexBuf.readSmallUint(classDefOffset + SOURCE_FILE_OFFSET));
+        this.sourceFile = dexBuf.getOptionalString(dexBuf.readOptionalUint(classDefOffset + SOURCE_FILE_OFFSET));
 
         int annotationsDirectoryOffset = dexBuf.readSmallUint(classDefOffset + ANNOTATIONS_OFFSET);
         this.annotationsDirectory = AnnotationsDirectory.newOrEmpty(dexBuf, annotationsDirectoryOffset);
diff --git a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBuffer.java b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBuffer.java
index dfc77bf0..fced24ab 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBuffer.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexBuffer.java
@@ -104,7 +104,19 @@ public class DexBuffer {
                      ((buf[offset+2] & 0xff) << 16) |
                      ((buf[offset+3]) << 24);
         if (result < 0) {
-            throw new ExceptionWithContext("Encountered uint that is out of range at offset 0x%x", offset);
+            throw new ExceptionWithContext("Encountered small uint that is out of range at offset 0x%x", offset);
+        }
+        return result;
+    }
+
+    public int readOptionalUint(int offset) {
+        byte[] buf = this.buf;
+        int result = (buf[offset] & 0xff) |
+                ((buf[offset+1] & 0xff) << 8) |
+                ((buf[offset+2] & 0xff) << 16) |
+                ((buf[offset+3]) << 24);
+        if (result < -1) {
+            throw new ExceptionWithContext("Encountered optional uint that is out of range at offset 0x%x", offset);
         }
         return result;
     }
diff --git a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexReader.java b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexReader.java
index 48f583d0..f70c4495 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexReader.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/dexbacked/DexReader.java
@@ -174,6 +174,13 @@ public class DexReader {
         return result;
     }
 
+    public int readOptionalUint() {
+        int o = offset;
+        int result = dexBuf.readOptionalUint(o);
+        offset = o + 4;
+        return result;
+    }
+
     public int readUshort() {
         int o = offset;
         int result = dexBuf.readUshort(offset);
diff --git a/dexlib2/src/test/java/org/jf/dexlib2/dexbacked/DexBufferTest.java b/dexlib2/src/test/java/org/jf/dexlib2/dexbacked/DexBufferTest.java
index 94538349..737842e4 100644
--- a/dexlib2/src/test/java/org/jf/dexlib2/dexbacked/DexBufferTest.java
+++ b/dexlib2/src/test/java/org/jf/dexlib2/dexbacked/DexBufferTest.java
@@ -70,6 +70,39 @@ public class DexBufferTest {
         dexBuf.readSmallUint(0);
     }
 
+    @Test
+    public void testReadOptionalUintSuccess() {
+        BareDexBuffer dexBuf = new BareDexBuffer(new byte[] {0x11, 0x22, 0x33, 0x44});
+        Assert.assertEquals(0x44332211, dexBuf.readSmallUint(0));
+
+        dexBuf = new BareDexBuffer(new byte[] {0x00, 0x00, 0x00, 0x00});
+        Assert.assertEquals(0, dexBuf.readSmallUint(0));
+
+        dexBuf = new BareDexBuffer(new byte[] {(byte)0xff, (byte)0xff, (byte)0xff, 0x7f});
+        Assert.assertEquals(0x7fffffff, dexBuf.readSmallUint(0));
+
+        dexBuf = new BareDexBuffer(new byte[] {(byte)0xff, (byte)0xff, (byte)0xff, (byte)0xff});
+        Assert.assertEquals(-1, dexBuf.readOptionalUint(0));
+    }
+
+    @Test(expected=ExceptionWithContext.class)
+    public void testReadOptionalUintTooLarge1() {
+        BareDexBuffer dexBuf = new BareDexBuffer(new byte[] {0x00, 0x00, 0x00, (byte)0x80});
+        dexBuf.readSmallUint(0);
+    }
+
+    @Test(expected=ExceptionWithContext.class)
+    public void testReadOptionalUintTooLarge2() {
+        BareDexBuffer dexBuf = new BareDexBuffer(new byte[] {(byte)0xff, (byte)0xff, (byte)0xff, (byte)0x80});
+        dexBuf.readSmallUint(0);
+    }
+
+    @Test(expected=ExceptionWithContext.class)
+    public void testReadOptionalUintTooLarge3() {
+        BareDexBuffer dexBuf = new BareDexBuffer(new byte[] {(byte)0xfe, (byte)0xff, (byte)0xff, (byte)0xff});
+        dexBuf.readSmallUint(0);
+    }
+
     @Test
     public void testReadUshort() {
         BareDexBuffer dexBuf = new BareDexBuffer(new byte[] {0x11, 0x22});