Method oppositeIndex

src/java/org/apache/poi/util/BinaryTree.java:445–452

Get the opposite index of the specified index @param index _KEY or _VALUE @return _VALUE (if _KEY was specified), else _KEY

(int index)

     * @return _VALUE (if _KEY was specified), else _KEY
     */
    private int oppositeIndex(int index)
    {

        // old trick ... to find the opposite of a value, m or n,
        // subtract the value from the sum of the two possible
        // values. (m + n) - m = n; (m + n) - n = m
        return _INDEX_SUM - index;
    }

    /**
     * do the actual lookup of a piece of data