return LongMath.log10(x.longValue(), mode);
    }

    int approxLog10 = (int) (log2(x, FLOOR) * LN_2 / LN_10);
    BigInteger approxPow = BigInteger.TEN.pow(approxLog10);
    int approxCmp = approxPow.compareTo(x);

    /*
     * We adjust approxLog10 and approxPow until they're equal to floor(log10(x)) and
     * 10^floor(log10(x)).
     */

    if (approxCmp > 0) {
      /*

 (placement === 'bottom' &&\n        floor(popperOffsets.top) < floor(refOffsets.bottom));\n\n    const overflowsLeft = floor(popperOffsets.left) < floor(boundaries.left);\n    const overflowsRight = floor(popperOffsets.right) > floor(boundaries.right);\n    const overflowsTop = floor(popperOffsets.top) < floor(boundaries.top);\n    const overflowsBottom =\n      floor(popperOffsets.bottom) > floor(boundaries.bottom);\n\n    const overflowsBoundaries =\n      (placement === 'left' && overflowsLeft)...

        .roundUnnecessaryShouldThrow()
        .test();
  }

  public void testRoundToDouble_negativeTwoToThe54MinusThree() {
    new RoundToDoubleTester(BigDecimal.valueOf((-1L << 54) - 3))
        .setExpectation(-Math.pow(2, 54), DOWN, CEILING)
        .setExpectation(
            DoubleUtils.nextDown(-Math.pow(2, 54)), FLOOR, UP, HALF_DOWN, HALF_UP, HALF_EVEN)

  }

  @CollectionSize.Require(SEVERAL)
  public void testFloorHole() {
    resetWithHole();
    assertEquals(a, navigableSet.floor(a));
    assertEquals(a, navigableSet.floor(b));
    assertEquals(c, navigableSet.floor(c));
  }

  @CollectionSize.Require(SEVERAL)
  public void testCeilingHole() {
    resetWithHole();
    assertEquals(a, navigableSet.ceiling(a));

  }

  /* Relies on the correctness of sqrt(int, FLOOR). */
  @GwtIncompatible // sqrt
  public void testSqrtExactMatchesFloorOrThrows() {
    for (int x : POSITIVE_INTEGER_CANDIDATES) {
      int floor = IntMath.sqrt(x, FLOOR);
      // We only expect an exception if x was not a perfect square.
      boolean isPerfectSquare = (floor * floor == x);
      try {
        assertEquals(floor, IntMath.sqrt(x, UNNECESSARY));

  }

  /* Relies on the correctness of sqrt(int, FLOOR). */
  @GwtIncompatible // sqrt
  public void testSqrtExactMatchesFloorOrThrows() {
    for (int x : POSITIVE_INTEGER_CANDIDATES) {
      int floor = IntMath.sqrt(x, FLOOR);
      // We only expect an exception if x was not a perfect square.
      boolean isPerfectSquare = (floor * floor == x);
      try {
        assertEquals(floor, IntMath.sqrt(x, UNNECESSARY));

  }

  @CollectionSize.Require(SEVERAL)
  public void testFloorHole() {
    resetWithHole();
    assertEquals(a, navigableSet.floor(a));
    assertEquals(a, navigableSet.floor(b));
    assertEquals(c, navigableSet.floor(c));
  }

  @CollectionSize.Require(SEVERAL)
  public void testCeilingHole() {
    resetWithHole();
    assertEquals(a, navigableSet.ceiling(a));

            }
            roundFloor = toX(roundFloorAsDouble, RoundingMode.FLOOR);
          }

          X deltaToFloor = minus(x, roundFloor);
          X deltaToCeiling = minus(roundCeiling, x);
          int diff = deltaToFloor.compareTo(deltaToCeiling);
          if (diff < 0) { // closer to floor
            return roundFloorAsDouble;
          } else if (diff > 0) { // closer to ceiling

            }
            roundFloor = toX(roundFloorAsDouble, RoundingMode.FLOOR);
          }

          X deltaToFloor = minus(x, roundFloor);
          X deltaToCeiling = minus(roundCeiling, x);
          int diff = deltaToFloor.compareTo(deltaToCeiling);
          if (diff < 0) { // closer to floor
            return roundFloorAsDouble;
          } else if (diff > 0) { // closer to ceiling

      }
    }
  }

  // Relies on the correctness of log10(long, FLOOR) and of pow(long, int).
  @GwtIncompatible // TODO
  public void testLog10Exact() {
    for (long x : POSITIVE_LONG_CANDIDATES) {
      int floor = LongMath.log10(x, FLOOR);
      boolean expectedSuccess = LongMath.pow(10, floor) == x;
      try {
        assertEquals(floor, LongMath.log10(x, UNNECESSARY));
        assertTrue(expectedSuccess);