code: public void resetEndOfs(int ofs) {
          if (endPageIdx == 0) {
              // because a precondition is that ofs is left of the
              // end
              end = ofs;
          } else {
              endPageIdx = ofs / pageSize;
              end = ofs % pageSize;
              if (end == 0 && pages.getLastNo() == endPageIdx) {
                  // this happens if getOfs() was called after the last character of a page was read
                  end += pageSize;
                  endPageIdx--;
              }
              endPage = pages.get(endPageIdx);
              endFilled = pages.getFilled(endPageIdx);
          }
      }
docs: Sets the current end ofs by to the specified value
  @param ofs &lt; getEndOfs()