/** Previous version of BigIntegerMath.factorial, kept for timing purposes. */
  private static BigInteger oldSlowFactorial(int n) {
    if (n <= 20) {
      return BigInteger.valueOf(LongMath.factorial(n));
    } else {
      int k = 20;
      return BigInteger.valueOf(LongMath.factorial(k)).multiply(oldSlowFactorial(k, n));
    }
  }

  /** Returns the product of {@code n1} exclusive through {@code n2} inclusive. */

      return addUnconditionalHolder(name, String.valueOf(value));
    }

    /**
     * Adds a name/value pair to the formatted output in {@code name=value} format.
     *
     * @since 18.0 (since 11.0 as {@code Objects.ToStringHelper.add()}).
     */
    @CanIgnoreReturnValue
    public ToStringHelper add(String name, char value) {
      return addUnconditionalHolder(name, String.valueOf(value));
    }

    /**

  }

  @SuppressWarnings("removal") // b/321209431 -- maybe just use valueOf here?
  @Generates
  Integer generateInteger() {
    return new Integer(generateInt());
  }

  @Generates
  long generateLong() {
    return generateInt();
  }

  @SuppressWarnings("removal") // b/321209431 -- maybe just use valueOf here?
  @Generates
  Long generateLongObject() {
    return new Long(generateLong());

    @Override
    public SampleElements<BigInteger> samples() {
      return new SampleElements<>(
          BigInteger.valueOf(1),
          BigInteger.valueOf(4),
          BigInteger.valueOf(3),
          BigInteger.valueOf(2),
          BigInteger.valueOf(5));
    }

    @Override
    public BigInteger[] createArray(int length) {
      return new BigInteger[length];
    }

    @Override

    } catch (NoSuchFieldException impossible) {
      throw new AssertionError(impossible);
    }
  }

  /**
   * Returns an optional enum constant for the given type, using {@link Enum#valueOf}. If the
   * constant does not exist, {@link Optional#absent} is returned. A common use case is for parsing
   * user input or falling back to a default enum constant. For example, {@code

        denominatorAccum *= q;
        numeratorBits += bits;
      }
    }
    return accum
        .multiply(BigInteger.valueOf(numeratorAccum))
        .divide(BigInteger.valueOf(denominatorAccum));
  }

  // Returns true if BigInteger.valueOf(x.longValue()).equals(x).
  @GwtIncompatible // TODO
  static boolean fitsInLong(BigInteger x) {
    return x.bitLength() <= Long.SIZE - 1;
  }

  /**
   * A reference implementation for {@code tryParse} that just catches the exception from {@link
   * Float#valueOf}.
   */
  private static @Nullable Float referenceTryParse(String input) {
    if (input.trim().length() < input.length()) {
      return null;
    }
    try {
      return Float.valueOf(input);
    } catch (NumberFormatException e) {
      return null;
    }
  }

        .that(Longs.tryParse(BigInteger.valueOf(MAX_VALUE).add(BigInteger.ONE).toString()))
        .isNull();
    assertWithMessage("Max long * 10")
        .that(Longs.tryParse(BigInteger.valueOf(MAX_VALUE).multiply(BigInteger.TEN).toString()))
        .isNull();
    assertWithMessage("Min long - 1")
        .that(Longs.tryParse(BigInteger.valueOf(MIN_VALUE).subtract(BigInteger.ONE).toString()))
        .isNull();

        .that(Longs.tryParse(BigInteger.valueOf(MAX_VALUE).add(BigInteger.ONE).toString()))
        .isNull();
    assertWithMessage("Max long * 10")
        .that(Longs.tryParse(BigInteger.valueOf(MAX_VALUE).multiply(BigInteger.TEN).toString()))
        .isNull();
    assertWithMessage("Min long - 1")
        .that(Longs.tryParse(BigInteger.valueOf(MIN_VALUE).subtract(BigInteger.ONE).toString()))
        .isNull();

            new Function<String, Integer>() {
              @Override
              public Integer apply(String from) {
                return Integer.valueOf(from);
              }
            });

    assertEquals(Integer.valueOf(1), iterator.next());
    assertEquals(Integer.valueOf(2), iterator.next());
    iterator.remove();
    assertEquals(asList("1", "3"), list);
  }

  public void testPoorlyBehavedTransform() {