@Override
    public V get(final long id) {
        if (size == 0) {
            return null;
        }
        final long[] a = faid;
        int offset = p2size;
        int n = 0;

        while (offset > 0) {
            final int nn = n + offset;
            if (nn < size && a[nn] <= id) {
                n = nn;
            }
            offset >>= 1;
        }
        if (a[n] == id) {
            return flv.get(n);
        }
        return null;
    }
@return the value for "id", or null if key unknown
main/src/main/java/cgeo/geocaching/brouter/util/FrozenLongMap.java