Core Foundation XML Services provides a nonvalidating parser that your applications can use to read data in XML format. Core Foundation's XML parser has two programming interfaces. The high-level interface parses an entire XML document and returns the data to you in the form of a CFXMLTree. There is also a configurable, callback-based API that allows event-driven parsing of an XML document. Event-driven parsing allows you to customize the parser's behavior so your application can respond only to the specific XML structures that interest you. Event-driven parsing is also useful for large documents because the parser doesn't have to construct the entire tree in memory.