1. A method of string search in a character stream, the method comprising: grouping string patterns of a dictionary into a plurality of string sets according to predetermined criteria; defining a set of parameterized search states each search state characterized by: domain parameters defining a search domain within said character stream; a string set from among said plurality of string sets; and a search rule; associating with each string pattern of each string set a search action identifying a search domain and a subsequent search state; acquiring an input text from said character stream; selecting a current search state and setting a current search domain to cover the entire input text; determining a current string set and a current rule corresponding to said current search state; executing a search procedure using said current rule to determine a location of a current string pattern belonging to said current string set within said current search domain; and ascertaining a subsequent search state and corresponding domain parameters.