diff --git a/src/object/client/Mirror.cpp b/src/object/client/Mirror.cpp
index c7e90cf..eac065d 100644
--- a/src/object/client/Mirror.cpp
+++ b/src/object/client/Mirror.cpp
@@ -8,6 +8,34 @@
 #include "object/client/CGPlayer.hpp"
 #include "object/client/CGUnit.hpp"
 #include "object/client/ObjMgr.hpp"
+#include <common/DataStore.hpp>
+
+#define MAX_DIRTY_MASKS 42
+
+/**
+ * Given a message data store, extract the dirty masks contained inside. Any masks not present are
+ * zeroed out. This function assumes the provided masks pointer has enough space for
+ * MAX_DIRTY_MASKS.
+ */
+int32_t ExtractDirtyMasks(CDataStore* msg, uint8_t* maskCount, uint32_t* masks) {
+    uint8_t count;
+    msg->Get(count);
+
+    *maskCount = count;
+
+    if (count > MAX_DIRTY_MASKS) {
+        return 0;
+    }
+
+    for (int32_t i = 0; i < count; i++) {
+        msg->Get(masks[i]);
+    }
+
+    // Zero out unused masks
+    memset(&masks[count], 0, (MAX_DIRTY_MASKS - count) * sizeof(uint32_t));
+
+    return 1;
+}
 
 /**
  * Given an object type hierarchy and GUID, return the number of DWORD blocks backing the object's