A data processing method and apparatus, the method comprising: storing, at a first memory location in a memory, a first copy of a set of data; storing, at a second memory location in a memory, a second copy of a set of data; comparing the first copy to the second copy so as to identify, within the first copy, a pointer, the pointer being located at a first data element of the first copy, the pointer specifying a second data element of the first copy; determining an offset for the identified pointer, the offset specifying a number of data elements between the first data element and the second data element; and modifying the first copy such that the pointer within the first copy specifies the second data element using only the first data element and the offset.