diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index 4b7af45..3711362 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -683,7 +683,7 @@
     return err;
 }
 
-int Parcel::compareData(const Parcel& other) {
+int Parcel::compareData(const Parcel& other) const {
     size_t size = dataSize();
     if (size != other.dataSize()) {
         return size < other.dataSize() ? -1 : 1;
diff --git a/libs/binder/include/binder/Parcel.h b/libs/binder/include/binder/Parcel.h
index 5cc0830..e2b23be 100644
--- a/libs/binder/include/binder/Parcel.h
+++ b/libs/binder/include/binder/Parcel.h
@@ -92,7 +92,7 @@
 
     LIBBINDER_EXPORTED status_t appendFrom(const Parcel* parcel, size_t start, size_t len);
 
-    LIBBINDER_EXPORTED int compareData(const Parcel& other);
+    LIBBINDER_EXPORTED int compareData(const Parcel& other) const;
     LIBBINDER_EXPORTED status_t compareDataInRange(size_t thisOffset, const Parcel& other,
                                                    size_t otherOffset, size_t length,
                                                    int* result) const;