@Override
      public boolean seekTo() throws IOException {
        if (top) {
          int r = this.delegate.seekTo(splitCell);
          if (r == HConstants.INDEX_KEY_MAGIC) {
            return true;
          }
          if (r < 0) {
            // midkey is < first key in file
            return this.delegate.seekTo();
          }
          if (r > 0) {
            return this.delegate.next();
          }
          return true;
        }

        boolean b = delegate.seekTo();
        if (!b) {
          return b;
        }
        // Check key.
        return (this.delegate.getReader().getComparator().compare(splitCell, getKey())) > 0;
      }
Creates a half file reader for a hfile referred to by an hfilelink.
@param context   Reader context info
@param fileInfo  HFile info
@param cacheConf CacheConfig
@param r         original reference file (contains top or bottom)
@param conf      Configuration
hbase-server/src/main/java/org/apache/hadoop/hbase/io/HalfStoreFileReader.java