static final byte UNSET = 0;

  /** Number of bits used to store the numbers of hash table bits (max 30). */
  private static final int HASH_TABLE_BITS_MAX_BITS = 5;

  /** Use high bits of metadata for modification count. */
  static final int MODIFICATION_COUNT_INCREMENT = (1 << HASH_TABLE_BITS_MAX_BITS);

  /** Bitmask that selects the low bits of metadata to get hashTableBits. */

/**
 * An immutable hash code of arbitrary bit length.
 *
 * @author Dimitris Andreou
 * @author Kurt Alfred Kluever
 * @since 11.0
 */
@ElementTypesAreNonnullByDefault
public abstract class HashCode {
  HashCode() {}

  /** Returns the number of bits in this hash code; a positive multiple of 8. */
  public abstract int bits();

  /**

  private final Key key;

  private final String toString;
  private final int bits;
  private final boolean supportsClone;

  MacHashFunction(String algorithmName, Key key, String toString) {
    this.prototype = getMac(algorithmName, key);
    this.key = checkNotNull(key);
    this.toString = checkNotNull(toString);
    this.bits = prototype.getMacLength() * Byte.SIZE;
    this.supportsClone = supportsClone(prototype);
  }

 *
 * ```
 *  0..63 : Length of the UTF-16 sequence that this range maps to. The offset is b2b3.
 * 64..79 : Offset by a fixed negative offset. The bottom 4 bits of b1 are the top 4 bits of the offset.
 * 80..95 : Offset by a fixed positive offset. The bottom 4 bits of b1 are the top 4 bits of the offset.
 *    119 : Ignored.
 *    120 : Valid.
 *    121 : Disallowed
 *    122 : Mapped inline to the sequence: [b2].

 * the operation and the desired access bits are compared to the SID
 * and access mask of each ACE. If the SID matches, the allow/deny flags
 * and access mask are considered. If the ACE is a "deny"
 * ACE and <i>any</i> of the desired access bits match bits in the access
 * mask of the ACE, the whole access check fails. If the ACE is an "allow"
 * ACE and <i>all</i> of the bits in the desired access bits match bits in

    long numeratorAccum = n;
    long denominatorAccum = 1;

    int bits = LongMath.log2(n, CEILING);

    int numeratorBits = bits;

    for (int i = 1; i < k; i++) {
      int p = n - i;
      int q = i + 1;

      // log2(p) >= bits - 1, because p >= n/2

      if (numeratorBits + bits >= Long.SIZE - 1) {
        // The numerator is as big as it can get without risking overflow.

    // the output, so the input must be at least 32 bits, since the output has to be that long
    assertPutString(new char[] {'p', HashTestUtils.randomLowSurrogate(new Random())});
  }

  public void testPutStringWithHighSurrogate() {
    // we pad because the dummy hash function we use to test this, merely copies the input into
    // the output, so the input must be at least 32 bits, since the output has to be that long

    // the output, so the input must be at least 32 bits, since the output has to be that long
    assertPutString(new char[] {'p', HashTestUtils.randomLowSurrogate(new Random())});
  }

  public void testPutStringWithHighSurrogate() {
    // we pad because the dummy hash function we use to test this, merely copies the input into
    // the output, so the input must be at least 32 bits, since the output has to be that long

pkg log, method (*Logger) Writer() io.Writer
pkg math/bits, func Add(uint, uint, uint) (uint, uint)
pkg math/bits, func Add32(uint32, uint32, uint32) (uint32, uint32)
pkg math/bits, func Add64(uint64, uint64, uint64) (uint64, uint64)
pkg math/bits, func Div(uint, uint, uint) (uint, uint)
pkg math/bits, func Div32(uint32, uint32, uint32) (uint32, uint32)
pkg math/bits, func Div64(uint64, uint64, uint64) (uint64, uint64)

   * metadata} is the size that the arrays should be allocated with. Once the arrays have been
   * allocated, the value of {@code metadata} combines the number of bits in the "short hash", in
   * its bottom {@value CompactHashing#HASH_TABLE_BITS_MAX_BITS} bits, with a modification count in
   * the remaining bits that is used to detect concurrent modification during iteration.
   */
  private transient int metadata;