1. A method for accessing data in a data structure, comprising: a) determining a node type of a first entry in a node array, wherein the node array defines a hierarchical relationship of a plurality of nodes in a markup language schema; b) determining based on the node type of the first entry whether the first entry includes an explicit size value; c) identifying, in response to determining that the first entry does not include an explicit size value, a predetermined size value associated with the node type of the first entry; and d) calculating an index for a second entry in the node array based on one of the explicit size value and the predetermined size value.