diff --git a/src/dfmt.d b/src/dfmt.d
index 1f1132e..febc193 100644
--- a/src/dfmt.d
+++ b/src/dfmt.d
@@ -58,7 +58,7 @@ int main(string[] args)
     else
     {
         File f = File(args[1]);
-        buffer = new ubyte[](f.size);
+        buffer = new ubyte[](cast(size_t)f.size);
         f.rawRead(buffer);
         if (inplace)
             output = File(args[1], "w");