TEXT PROCESSING APPARATUS, TEXT PROCESSING METHOD AND TEXT PROCESSING PROGRAM

摘要

PROBLEM TO BE SOLVED: To efficiently create a phrase tree allowed to be used for encoding text data at a high compression ratio.SOLUTION: A frequency counting means 1c counts up the appearance frequency of a selected character given to a node of a decision position. When the appearance frequency of the selected character given to the node of the decision position reaches a predetermined threshold, a node addition means 1b adds a slave node corresponding to the selected character for the node of the decision position to a phrase tree 2a. When there exists the slave node corresponding to the selected character for the node of the decision position, the node addition means 1b changes the decision position to the slave node corresponding to the selected character for the node of the decision position. When the slave node corresponding to the selected character does not exist and the appearance frequency of the selected character given to the node of the decision position does not reach the predetermined threshold, a decision position change means 1d changes the decision position to a slave node of a node of a route.