core/src/main/java/com/orientechnologies/orient/core/storage/cache/chm/FrequencySketch.java
private boolean incrementAt(final int i, final int j) {
    final int offset = j << 2;
    final long mask = (0xfL << offset);
    if ((table[i] & mask) != mask) {
      table[i] += (1L << offset);
      return true;
    }
    return false;
  }
private boolean incrementAt(final int i, final int j) {
    final int offset = j << 2;
    final long mask = (0xfL << offset);
    if ((table[i] & mask) != mask) {
      table[i] += (1L << offset);
      return true;
    }
    return false;
  }
Increments the specified counter by 1 if it is not already at the maximum value (15).

@param i the table index (16 counters)
@param j the counter to increment

@return if incremented