code: public static int lastOrdinalIndexOf(final CharSequence str, final CharSequence searchStr, final int ordinal) {
          return ordinalIndexOf(str, searchStr, ordinal, true);
      }
docs: <p>Finds the n-th last index within a String, handling {@code null}.
  This method uses {@link String#lastIndexOf(String)}.</p>
  
  <p>A {@code null} String will return {@code -1}.</p>
  
  <pre>
  StringUtils.lastOrdinalIndexOf(null, *, *)          = -1
  StringUtils.lastOrdinalIndexOf(*, null, *)          = -1
  StringUtils.lastOrdinalIndexOf("", "", *)           = 0
  StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 1)  = 7
  StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 2)  = 6
  StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 1)  = 5
  StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 2)  = 2
  StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 1) = 4
  StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 2) = 1
  StringUtils.lastOrdinalIndexOf("aabaabaa", "", 1)   = 8
  StringUtils.lastOrdinalIndexOf("aabaabaa", "", 2)   = 8
  </pre>
  
  <p>Note that 'tail(CharSequence str, int n)' may be implemented as: </p>
  
  <pre>
  str.substring(lastOrdinalIndexOf(str, "\n", n) + 1)
  </pre>
  
  @param str  the CharSequence to check, may be null
  @param searchStr  the CharSequence to find, may be null
  @param ordinal  the n-th last {@code searchStr} to find
  @return the n-th last index of the search CharSequence,
  {@code -1} ({@code INDEX_NOT_FOUND}) if no match or {@code null} string input
  @since 2.5
  @since 3.0 Changed signature from lastOrdinalIndexOf(String, String, int) to lastOrdinalIndexOf(CharSequence, CharSequence, int)