"math"
	"math/bits"
)

// Mask allows filtering by a bitset mask.
type Mask uint64

const (
	// MaskAll is the mask for all entries.
	MaskAll Mask = math.MaxUint64
)

// MaskFromMaskable extracts mask from an interface.
func MaskFromMaskable(m Maskable) Mask {
	return Mask(m.Mask())
}

// Contains returns whether *all* flags in other is present in t.
func (t Mask) Contains(other Mask) bool {
	return t&other == other

	sub := &Sub[T]{ch: subCh, types: Mask(mask.Mask()), filter: filter}
	ps.subs = append(ps.subs, sub)

	// We hold a lock, so we are safe to update
	combined := Mask(atomic.LoadUint64(&ps.types))
	combined.Merge(Mask(mask.Mask()))
	atomic.StoreUint64(&ps.types, uint64(combined))

	go func() {
		<-doneCh

		ps.Lock()
		defer ps.Unlock()
		var remainTypes Mask
		for i, s := range ps.subs {
			if s == sub {

    int hash = smearedHash(object);
    int mask = hashTableMask();
    int tableIndex = hash & mask;
    int next = CompactHashing.tableGet(requireTable(), tableIndex);
    if (next == UNSET) { // uninitialized bucket
      if (newSize > mask) {
        // Resize and add new entry
        mask = resizeTable(mask, CompactHashing.newCapacity(mask), hash, newEntryIndex);
      } else {

  static int getHashPrefix(int value, int mask) {
    return value & ~mask;
  }

  /** Returns the index, or 0 if the entry is "null". */
  static int getNext(int entry, int mask) {
    return entry & mask;
  }

  /** Returns a new value combining the prefix and suffix using the given mask. */
  static int maskCombine(int prefix, int suffix, int mask) {
    return (prefix & ~mask) | (suffix & mask);
  }

  static int remove(

  static int getHashPrefix(int value, int mask) {
    return value & ~mask;
  }

  /** Returns the index, or 0 if the entry is "null". */
  static int getNext(int entry, int mask) {
    return entry & mask;
  }

  /** Returns a new value combining the prefix and suffix using the given mask. */
  static int maskCombine(int prefix, int suffix, int mask) {
    return (prefix & ~mask) | (suffix & mask);
  }

  static int remove(

    TYPE_DISALLOWED -> TYPE_DISALLOWED

    else -> error("unexpected type: $type")
  }
}

internal infix fun Byte.and(mask: Int): Int = toInt() and mask

internal infix fun Short.and(mask: Int): Int = toInt() and mask

    int hash = smearedHash(object);
    int mask = hashTableMask();
    int tableIndex = hash & mask;
    int next = CompactHashing.tableGet(requireTable(), tableIndex);
    if (next == UNSET) { // uninitialized bucket
      if (newSize > mask) {
        // Resize and add new entry
        mask = resizeTable(mask, CompactHashing.newCapacity(mask), hash, newEntryIndex);
      } else {

	ch3 := make(chan Maskable, 1)
	doneCh := make(chan struct{})
	defer close(doneCh)
	// Mask matches maskString, should get result
	if err := ps.Subscribe(Mask(1), ch1, doneCh, func(entry Maskable) bool { return true }); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	// Mask matches maskString, should get result
	if err := ps.Subscribe(Mask(1|2), ch2, doneCh, func(entry Maskable) bool { return true }); err != nil {

	// AVX2GATHER mask/index/dest #UD cases.
	VPGATHERQQ Y2, (BP)(X2*2), Y2   // ERROR "mask, index, and destination registers should be distinct"
	VPGATHERQQ Y2, (BP)(X2*2), Y7   // ERROR "mask, index, and destination registers should be distinct"
	VPGATHERQQ Y2, (BP)(X7*2), Y2   // ERROR "mask, index, and destination registers should be distinct"

  }

  private RegularImmutableMap(
      Entry<K, V>[] entries, @CheckForNull @Nullable ImmutableMapEntry<K, V>[] table, int mask) {
    this.entries = entries;
    this.table = table;
    this.mask = mask;
  }

  /**
   * Checks if the given key already appears in the hash chain starting at {@code keyBucketHead}. If