The zerg library contains a c/flex lexical scanner for blast reports and a set of supporting functions. it is centered on a "get_token" function that scans the input for specified lexical elements and, when one is found, returns its code and value to the user.

it is intended to be fast: for that the authors used flex, which provides simple regular expression matching and input buffering in the generated c scanner. and it is intended to be simple in the sense of providing just a lexical scanner, with no features whose support could slow down its main function.