masked: Prefix{},
		},
	}
	for _, test := range tests {
		t.Run(test.prefix.String(), func(t *testing.T) {
			got := test.prefix.Masked()
			if got != test.masked {
				t.Errorf("Masked=%s, want %s", got, test.masked)
			}
		})
	}
}

func TestPrefix(t *testing.T) {
	tests := []struct {
		prefix      string
		ip          Addr
		bits        int
		str         string

	base := subnet.Masked().Addr()
	bytes := base.AsSlice()
	// get all the host bits from the subnet
	n := 8*len(bytes) - subnet.Bits()
	// set all the host bits to 1
	for i := len(bytes) - 1; i >= 0 && n > 0; i-- {
		if n >= 8 {
			bytes[i] = 0xff
			n -= 8
		} else {
			mask := ^uint8(0) >> (8 - n)
			bytes[i] |= mask
			break
		}
	}

        .isEqualTo("Client-sent frames must be masked.")
    }
  }

  @Test fun serverSentFramesMustNotBeMasked() {
    data.write("8180".decodeHex())
    assertFailsWith<ProtocolException> {
      clientReader.processNextFrame()
    }.also { expected ->
      assertThat(expected.message)
        .isEqualTo("Server-sent frames must not be masked.")
    }
  }

  @Test fun controlFramePayloadMax() {

	var mask [gcmBlockSize]byte

	for len(in) >= gcmBlockSize {
		g.cipher.Encrypt(mask[:], counter[:])
		gcmInc32(counter)

		subtle.XORBytes(out, in, mask[:])
		out = out[gcmBlockSize:]
		in = in[gcmBlockSize:]
	}

	if len(in) > 0 {
		g.cipher.Encrypt(mask[:], counter[:])
		gcmInc32(counter)
		subtle.XORBytes(out, in, mask[:])
	}
}

	// the address of the first word referenced by mask.
	addr uintptr

	// mask is a bitmask where each bit corresponds to pointer-words after addr.
	// Bit 0 is the pointer-word at addr, Bit 1 is the next word, and so on.
	// If a bit is 1, then there is a pointer at that word.
	// nextFast and next mask out bits in this mask as their pointers are processed.
	mask uintptr

	maskUpdatedChan = make(chan struct{})
	disableSigChan = make(chan uint32)
	enableSigChan = make(chan uint32)
	go func() {
		// Signal masks are per-thread, so make sure this goroutine stays on one
		// thread.
		LockOSThread()
		defer UnlockOSThread()
		// The sigBlocked mask contains the signals not active for os/signal,
		// initially all signals except the essential. When signal.Notify()/Stop is called,

//go:nosplit
//go:nowritebarrierrec
func sigaddset(mask *sigset, i int) {
	(*mask)[(i-1)/32] |= 1 << ((uint32(i) - 1) & 31)
}

func sigdelset(mask *sigset, i int) {
	(*mask)[(i-1)/32] &^= 1 << ((uint32(i) - 1) & 31)
}

//go:nosplit
func sigfillset(mask *[4]uint32) {
	(*mask)[0], (*mask)[1], (*mask)[2], (*mask)[3] = ^uint32(0), ^uint32(0), ^uint32(0), ^uint32(0)

  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(

#include <time.h>
#include <unistd.h>

extern void IntoGoAndBack();

int CheckBlocked() {
	sigset_t mask;
	sigprocmask(SIG_BLOCK, NULL, &mask);
	return sigismember(&mask, SIGIO);
}

static void* sigthreadfunc(void* unused) {
	sigset_t mask;
	sigemptyset(&mask);
	sigaddset(&mask, SIGIO);
	sigprocmask(SIG_BLOCK, &mask, NULL);
	IntoGoAndBack();
	return NULL;
}

int RunSigThread() {
	int tries;
	pthread_t thread;

//go:nosplit
//go:nowritebarrierrec
func sigaddset(mask *sigset, i int) {
	(*mask)[(i-1)/64] |= 1 << ((uint32(i) - 1) & 63)
}

func sigdelset(mask *sigset, i int) {
	(*mask)[(i-1)/64] &^= 1 << ((uint32(i) - 1) & 63)
}

//go:nosplit
func sigfillset(mask *[2]uint64) {
	(*mask)[0], (*mask)[1] = ^uint64(0), ^uint64(0)