private static DiskRangeList findExactPosition(DiskRangeList ranges, long offset) {
    if (offset < 0) return ranges;
    ranges = findUpperBound(ranges, offset);
    ranges = findLowerBound(ranges, offset);
    if (offset < ranges.getOffset() || offset >= ranges.getEnd()) {
      throwRangesError(ranges, offset, offset);
    }
    return ranges;
  }
Finds compressed offset in a stream and makes sure iter points to its position.
     This may be necessary for obscure combinations of compression and encoding boundaries.
ql/src/java/org/apache/hadoop/hive/ql/io/orc/encoded/EncodedReaderImpl.java