StrRef - refer to existing strings

The StrRef class is a simple pointer/length pair representing a string. The StrRef class is is derived from StrPtr and does not add a great deal of new functionality to that class, with the exception of methods that make the pointer mutable (and therefore usable), whereas a base StrPtr is read-only.

As its name suggests, a StrRef serves as a reference to existing data, as the class does not perform its own memory allocation. The StrBuf class is most useful when storing and manipulating existing strings.