public void write(Directory directory, String segmentName, FieldInfos infos, IOContext context) throws IOException {
final String fileName = IndexFileNames.segmentFileName(segmentName, "", FIELD_INFOS_EXTENSION);
IndexOutput output = directory.createOutput(fileName, context);
boolean success = false;
try {
output.writeVInt(FORMAT_PREFLEX_RW);
output.writeVInt(infos.size());
for (FieldInfo fi : infos) {
byte bits = 0x0;
if (fi.hasVectors()) bits |= STORE_TERMVECTOR;
if (fi.omitsNorms()) bits |= OMIT_NORMS;