As a general rule, don't overwrite your input data. That's a hardcore space optimization that can end up making your program slower. At the minimum it will lead

As a general rule, don't overwrite your input data. That's a hardcore space optimization that can end up making your program slower. At the minimum it will lead to headaches later on. Are you sure you won't need the pristine input for diagnostic and error messages later on? Do you always have at least 1 separator character to overwrite in the first place?