/**
* Read the GSUB table.
* @throws IOException In case of a I/O problem
*/
private void readGSUB() throws IOException {
TTFTableName tableTag = TTFTableName.GSUB;
// Initialize temporary state
initATState();
// Read glyph substitution (GSUB) table
TTFDirTabEntry dirTab = ttf.getDirectoryEntry ( tableTag );
if ( gpos != null ) {