}

  private void setPredecessor(int entry, int pred) {
    requirePredecessors()[entry] = pred + 1;
  }

  private void setSucceeds(int pred, int succ) {
    if (pred == ENDPOINT) {
      firstEntry = succ;
    } else {
      setSuccessor(pred, succ);
    }

    if (succ == ENDPOINT) {
      lastEntry = pred;
    } else {
      setPredecessor(succ, pred);
    }
  }

  @Override

  }

  private void setPredecessor(int entry, int pred) {
    long predMask = (~0L) << 32;
    links[entry] = (links[entry] & ~predMask) | ((long) pred << 32);
  }

  private void setSucceeds(int pred, int succ) {
    if (pred == ENDPOINT) {
      firstEntry = succ;
    } else {
      setSuccessor(pred, succ);
    }
    if (succ == ENDPOINT) {
      lastEntry = pred;
    } else {
      setPredecessor(succ, pred);

    }

    private void succeedsInValueSet(
        @Nullable ValueEntry<K, V> pred, @Nullable ValueEntry<K, V> succ) {
      if (pred == null) {
        firstEntry = succ;
      } else {
        pred.successorInValueSet = succ;
      }
      if (succ == null) {
        lastEntry = pred;
      } else {
        succ.predecessorInValueSet = pred;
      }
    }

    /** Constructor for the header node. */
    AvlNode() {
      this.elem = null;
      this.elemCount = 1;
    }

    // For discussion of pred() and succ(), see the comment on the pred and succ fields.

    private AvlNode<E> pred() {
      return requireNonNull(pred);
    }

    private AvlNode<E> succ() {
      return requireNonNull(succ);
    }

    restart:
    while (true) {
      Waiter pred = null;
      Waiter curr = waitersField;
      if (curr == Waiter.TOMBSTONE) {
        return; // give up if someone is calling complete
      }
      Waiter succ;
      while (curr != null) {
        succ = curr.next;
        if (curr.thread != null) { // we aren't unlinking this node, update pred.
          pred = curr;

    restart:
    while (true) {
      Waiter pred = null;
      Waiter curr = waitersField;
      if (curr == Waiter.TOMBSTONE) {
        return; // give up if someone is calling complete
      }
      Waiter succ;
      while (curr != null) {
        succ = curr.next;
        if (curr.thread != null) { // we aren't unlinking this node, update pred.
          pred = curr;

			continue
		}
	}
	pred := func(c rune) bool { return c == 'X' }
	var fieldsFuncTests = []FieldsTest{
		{"", []string{}},
		{"XX", []string{}},
		{"XXhiXXX", []string{"hi"}},
		{"aXXbXXXcX", []string{"a", "b", "c"}},
	}
	for _, tt := range fieldsFuncTests {
		b := []byte(tt.s)
		a := FieldsFunc(b, pred)

		// Appending to the results should not change future results.

	s3Err = authenticateRequest(ctx, r, action)
	reqInfo := logger.GetReqInfo(ctx)
	if reqInfo == nil {
		return cred, owner, ErrAccessDenied
	}

	cred = reqInfo.Cred
	owner = reqInfo.Owner
	if s3Err != ErrNone {
		return cred, owner, s3Err
	}

	return cred, owner, authorizeRequest(ctx, r, action)
}

	// Find the user for the request sender (as it may be sent via a service
	// account or STS account):
	requestorUser := cred.AccessKey
	requestorParentUser := cred.AccessKey
	requestorGroups := cred.Groups
	requestorIsDerivedCredential := false
	if cred.IsServiceAccount() || cred.IsTemp() {
		requestorParentUser = cred.ParentUser
		requestorIsDerivedCredential = true
	}

	// Check if we are creating svc account for request sender.

	r := &http.Request{Header: formValues}
	cred, _, s3Err := checkKeyValid(r, accessKey)
	if s3Err != ErrNone {
		return cred, s3Err
	}
	policy := formValues.Get("Policy")
	signature := formValues.Get(xhttp.AmzSignatureV2)
	if !compareSignatureV2(signature, calculateSignatureV2(policy, cred.SecretKey)) {
		return cred, ErrSignatureDoesNotMatch
	}
	return cred, ErrNone
}