如何解析XML String并检索元素的char索引？

As in the title, I am currently dealing with the need to parse an XML formatted String while being able to store information about the character index of the start of an element tag and the end of an element tag within the original String. I've looked at SAX and DOM and I can't seem to find anything that would provide me that data. Any suggestions?As in the title, I am currently dealing with th