+ // Check for zero length files because some systems croak when you try to
+ // mmap an empty file.
+ size_t A_size = FileA.getSize();
+ size_t B_size = FileB.getSize();
+
+ // If they are both zero sized then they're the same
+ if (A_size == 0 && B_size == 0)
+ return 0;
+ // If only one of them is zero sized then they can't be the same
+ if ((A_size == 0 || B_size == 0))
+ return 1;
+
+ // Now its safe to mmap the files into memory becasue both files
+ // have a non-zero size.