file = originalInput == null ? sstable.getFileDataInput(positionToSeek) : originalInput;
AtomDeserializer deserializer = emptyColumnFamily.metadata().getOnDiskDeserializer(file, sstable.descriptor.version);
file.seek(positionToSeek);
FileMark mark = file.mark();
// We remenber when we are whithin a slice to avoid some comparison
boolean inSlice = false;
// scan from index start