java.util.ArrayDeque#isEmpty ( )源码实例Demo

/**
     * Given a vertex, find all of the vertices in its component.
     *
     * @param graph The graph containing the vertex.
     * @param seedVxId The vertex to start from.
     * @param verticesToArrange a BitSet specifying which vertices to arrange.
     *
     * @return A Set<Integer%gt; containing all of the vertices in the same
     * component as rootVxId.
     */
    @Deprecated
    public static Set<Integer> getComponentContainingVertex(final GraphReadMethods graph, final int seedVxId, final BitSet verticesToArrange) {
        final Set<Integer> component = new HashSet<>();

        final ArrayDeque<Integer> neighbours = new ArrayDeque<>();
        neighbours.add(seedVxId);
        component.add(seedVxId);
        while (!neighbours.isEmpty()) {
            final Integer vxId = neighbours.removeFirst();
//            component.add(vxId);
//            Debug.debug("@added to component: %d (%d)\n", vxId, component.size());
            final int nNeighbours = graph.getVertexNeighbourCount(vxId);
            for (int nbPosition = 0; nbPosition < nNeighbours; nbPosition++) {
                final int nbId = graph.getVertexNeighbour(vxId, nbPosition);

                if (verticesToArrange.get(nbId) && !component.contains(nbId)) {
                    neighbours.add(nbId);
                    component.add(nbId);
                }
            }
        }

        return component;
    }
 

/**
 * Executes the queue of pending jobs.
 * 
 * @param jobSource
 *            the job source
 * @throws InterruptedException
 *             if interrupted while waiting
 */
public void runEventLoop(JobSource jobSource) throws InterruptedException {
    ArrayDeque<Job> scriptJobs = this.scriptJobs;
    ArrayDeque<Job> promiseJobs = this.promiseJobs;
    ArrayDeque<Job> finalizerJobs = this.finalizerJobs;
    ConcurrentLinkedDeque<Job> asyncJobs = this.asyncJobs;
    ArrayDeque<Object> unhandledRejections = this.unhandledRejections;
    for (;;) {
        while (!(scriptJobs.isEmpty() && promiseJobs.isEmpty() && finalizerJobs.isEmpty() && asyncJobs.isEmpty())) {
            executeJobs(scriptJobs);
            executeJobs(promiseJobs);
            executeJobs(finalizerJobs);
            executeJobs(asyncJobs);
        }
        if (!unhandledRejections.isEmpty()) {
            throw new UnhandledRejectionException(unhandledRejections.poll());
        }
        Job job = jobSource.nextJob();
        if (job == null) {
            break;
        }
        enqueueScriptJob(job);
    }
}
 

/** Returns bitset marking states reachable from the initial state. */
private static BitSet getLiveStatesFromInitial(Automaton a) {
  int numStates = a.getNumStates();
  BitSet live = new BitSet(numStates);
  if (numStates == 0) {
    return live;
  }
  ArrayDeque<Integer> workList = new ArrayDeque<>();
  live.set(0);
  workList.add(0);

  Transition t = new Transition();
  while (workList.isEmpty() == false) {
    int s = workList.removeFirst();
    int count = a.initTransition(s, t);
    for(int i=0;i<count;i++) {
      a.getNextTransition(t);
      if (live.get(t.dest) == false) {
        live.set(t.dest);
        workList.add(t.dest);
      }
    }
  }

  return live;
}
 

public static void findMaximumSlidingWindow(int[] arr,
                                            int windowSize) {
    if (arr.length < windowSize) return;

    ArrayDeque<Integer> list = new ArrayDeque();
    for (int i = 0; i < windowSize; i++) {

        while (!list.isEmpty() && arr[i] >= arr[list.peekLast()]) {
            list.removeLast();
        }
        list.addLast(i);
    }

    System.out.print(arr[list.peekFirst()] + " ");


    for (int i = windowSize; i < arr.length; i++) {

        while (!list.isEmpty() && arr[i] >= arr[list.peekLast()]) {
            list.removeLast();
        }

        if (!list.isEmpty() && list.peekFirst() <= i - windowSize) {
            list.removeFirst();
        }

        list.addLast(i);
        System.out.print(arr[list.peekFirst()] + " ");
    }
}
 

/**
 * Returns a list of all distinct paths from roots of the network to leaves. The list can be in
 * arbitrary orders and can contain duplicate paths if there are multiple edges from two nodes.
 */
public static <NodeT, EdgeT> List<List<NodeT>> allPathsFromRootsToLeaves(
    Network<NodeT, EdgeT> network) {
  ArrayDeque<List<NodeT>> paths = new ArrayDeque<>();
  // Populate the list with all roots
  for (NodeT node : network.nodes()) {
    if (network.inDegree(node) == 0) {
      paths.add(ImmutableList.of(node));
    }
  }

  List<List<NodeT>> distinctPathsFromRootsToLeaves = new ArrayList<>();
  while (!paths.isEmpty()) {
    List<NodeT> path = paths.removeFirst();
    NodeT lastNode = path.get(path.size() - 1);
    if (network.outDegree(lastNode) == 0) {
      distinctPathsFromRootsToLeaves.add(new ArrayList<>(path));
    } else {
      for (EdgeT edge : network.outEdges(lastNode)) {
        paths.addFirst(
            ImmutableList.<NodeT>builder()
                .addAll(path)
                .add(network.incidentNodes(edge).target())
                .build());
      }
    }
  }
  return distinctPathsFromRootsToLeaves;
}
 

@Override
public void onComplete() {
    final ArrayDeque<UnicastSubject<T>> ws = windows;
    while (!ws.isEmpty()) {
        ws.poll().onComplete();
    }
    actual.onComplete();
}
 

static ImmutableSet<String> computeRootsFromIncludes(Iterable<String> includes) {
  List<String> roots = new ArrayList<>();

  for (String includePath : includes) {
    ArrayDeque<String> components = new ArrayDeque<>();
    for (String component : Splitter.on('/').split(includePath)) {
      components.add(unescape(component));
      if (isMeta(component)) {
        break;
      }
    }
    components.removeLast();
    if (components.isEmpty()) {
      return ImmutableSet.of("");
    }
    roots.add(Joiner.on('/').join(components));
  }

  // Remove redundant roots - e.g. "foo" covers all paths that start with "foo/"
  Collections.sort(roots);
  int r = 0;
  while (r < roots.size() - 1) {
    if (roots.get(r + 1).startsWith(roots.get(r) + "/")) {
      roots.remove(r + 1);
    } else {
      r++;
    }
  }

  return ImmutableSet.copyOf(roots);
}
 

public int[] maxSlidingWindow(int[] nums, int k) {
    int len = nums.length;
    // 特判
    if (len == 0) {
        return new int[]{};
    }
    // 结果集
    List<Integer> res = new ArrayList<>();
    // 滑动窗口，注意：保存的是索引值
    ArrayDeque<Integer> deque = new ArrayDeque<>(k);

    for (int i = 0; i < len; i++) {
        // 当元素从左边界滑出的时候，如果它恰恰好是滑动窗口的最大值
        // 那么将它弹出
        if (i >= k && i - k == deque.getFirst()) {
            deque.pollFirst();
        }

        // 如果滑动窗口非空，新进来的数比队列里已经存在的数还要大
        // 则说明已经存在数一定不会是滑动窗口的最大值（它们毫无出头之日）
        // 将它们弹出
        while (!deque.isEmpty() && nums[deque.peekLast()] <= nums[i]) {
            deque.pollLast();
        }
        deque.add(i);
        // 队首一定是滑动窗口的最大值的索引
        if (i >= k - 1) {
            res.add(nums[deque.peekFirst()]);
        }
    }

    int size = res.size();
    int[] result = new int[size];

    for (int i = 0; i < size; i++) {
        result[i] = res.get(i);
    }
    return result;
}
 

/**
 * Get the normalized path for the given file path.
 * Any parent directories (..) will be resolved.
 * @param file file path
 * @return 
 */
public static String getNormalizedPath(String file) {
    Matcher m = schemedPathPattern.matcher(file);
    if(!m.find()) {
        return Directory.ROOT_DIRECTORY;
    }
    String scheme = m.group(1);
    String path = m.group(2);
    if(scheme == null) {
        scheme = "";
    }
    String[] st = path.split("(\\\\|/)+");
    ArrayDeque<String> segmentList = new ArrayDeque<String>();
    for(String segment : st) {
        if("..".equals(segment)) {
            segmentList.pollFirst();
            continue;
        }
        segmentList.offerFirst(segment);
    }
    if(segmentList.isEmpty() && scheme.isEmpty()) {
        return Directory.ROOT_DIRECTORY;
    }
    StringBuilder sb = new StringBuilder();
    sb.append(scheme);
    while(!segmentList.isEmpty()) {
        sb.append(segmentList.pollLast());
        if(segmentList.peekLast() != null) {
            sb.append('/');
        }
    }
    return sb.length() == 0 ? Directory.ROOT_DIRECTORY : sb.toString();
}
 

@SubscribeEvent
public void tickEnd(TickEvent.WorldTickEvent event) {
    if (event.side != Side.SERVER) {
        return;
    }

    if (event.phase == TickEvent.Phase.END) {

        World world = event.world;
        int dim = world.provider.getDimension();

        ArrayDeque<ChunkPos> chunks = chunksToGen.get(dim);

        if (chunks != null && !chunks.isEmpty()) {
            ChunkPos c = chunks.pollFirst();
            long worldSeed = world.getSeed();
            Random rand = new Random(worldSeed);
            long xSeed = rand.nextLong() >> 2 + 1L;
            long zSeed = rand.nextLong() >> 2 + 1L;
            rand.setSeed(xSeed * c.x + zSeed * c.z ^ worldSeed);
            OreGenerator.instance.generateWorld(rand, c.x, c.z, world, false);
            chunksToGen.put(dim, chunks);
        } else if (chunks != null) {
            chunksToGen.remove(dim);
        }
    }
}
 

private Optional<double[][]> toMatrix(ArrayDeque<double[]> sampledFeatures) {
    Optional<double[][]> samples;
    if (sampledFeatures.isEmpty()) {
        samples = Optional.empty();
    } else {
        samples = Optional.of(sampledFeatures.toArray(new double[0][0]));
    }
    return samples;
}
 

/**
 * @param pathRecord 点击的展开路径记录
 *                   通过路径直接恢复视图序列
 */
private void restoreAllInfo(ArrayDeque<MenuItem> pathRecord) {
    mPathRecord.clear();
    while (!pathRecord.isEmpty()) {
        mCurMenuItem = pathRecord.getLast();
        addOneLevel();
        pathRecord.removeLast();
    }

}
 

private <T> boolean search(MimedType<T> target, ArrayDeque<PathInfo> bestMatch, ArrayDeque<PathInfo> currentPath, MimedType currentSearch, HashSet<MimedType> searched) {
    if (target.isTypeOf(currentSearch)) {
        bestMatch.clear();
        bestMatch.addAll(currentPath);
        return true;
    }

    // the current path must have potential to be better than the best match
    if (!bestMatch.isEmpty() && PathInfo.distance(currentPath) >= PathInfo.distance(bestMatch))
        return false;

    // prevent reentrancy
    if (searched.contains(currentSearch))
        return false;

    boolean found = false;
    searched.add(currentSearch);
    ConverterTransformers<Object, Object> converterTransformers = outputs.getAll(currentSearch);
    for (MimedType candidate: converterTransformers.keySet()) {
        // this simulates the mime results of a transform
        MimedType newSearch = new MimedType(candidate.type, mimeReplace(currentSearch.mime, candidate.mime));

        PathInfo path = new PathInfo();
        path.transformer = converterTransformers.get(candidate);
        path.mime = newSearch.mime;
        path.candidate = candidate;
        currentPath.addLast(path);
        try {
            found |= search(target, bestMatch, currentPath, newSearch, searched);
        }
        finally {
            currentPath.removeLast();
        }
    }

    if (found) {
        // if this resulted in a success,
        // clear this from the currentSearch list, because we know this leads
        // to a potential solution. maybe we can arrive here faster.
        searched.remove(currentSearch);
    }

    return found;
}
 

<T> Optional<Pair<Falsification<T>, PrecursorDataPair<T>>> findFalsifyingValue(
    Property<T> prop, LongSupplier clock) {
  
  Guidance guidance = config.guidance();
  
  Distribution<T> randomDistribution =  new BoundarySkewedDistribution<>(config, prop.getGen()); 
  ArrayDeque<long[]> toVisit = new ArrayDeque<>();

  Distribution<T> distribution;

  long endTime = clock.getAsLong() + config.testingTimeMillis();
  for (int i = 0; i != config.examples(); i++) {
    if (toVisit.isEmpty()) {
      distribution = randomDistribution;
    } else {
      distribution = new ForcedDistribution<>(config, prop.getGen(), toVisit.pop());
    }
    
    PrecursorDataPair<T> t = distribution.generate();
    if (checkHash(t)) {
      continue;
    }  
    
    examplesUsed = examplesUsed + 1;
    guidance.newExample(t.precursor());
    
    Optional<Falsification<T>> falsification = prop.tryFalsification(t.value());
    guidance.exampleExecuted();

    if (falsification.isPresent()) {
      return falsification.map(f -> Pair.of(f, t));
    } else {
      toVisit.addAll(guidance.suggestValues(i,t.precursor()));
    }
    
    guidance.exampleComplete();

    if (config.testingTimeMillis() > 0 && clock.getAsLong() > endTime) {
      break;
    }
  }

  return Optional.empty();
}
 

@GuardedBy("this")
private void regenerateSortedNodes() {
  mSortedNodes.clear();

  if (mBindings.size() == 0) {
    return;
  }

  final ArraySet<ValueNode> leafNodes = new ArraySet<>();
  final SimpleArrayMap<ValueNode, Integer> nodesToOutputsLeft = new SimpleArrayMap<>();

  for (int i = 0, bindingsSize = mBindings.size(); i < bindingsSize; i++) {
    final ArrayList<ValueNode> nodes = mBindings.get(i).getAllNodes();
    for (int j = 0, nodesSize = nodes.size(); j < nodesSize; j++) {
      final ValueNode node = nodes.get(j);
      final int outputCount = node.getOutputCount();
      if (outputCount == 0) {
        leafNodes.add(node);
      } else {
        nodesToOutputsLeft.put(node, outputCount);
      }
    }
  }

  if (!nodesToOutputsLeft.isEmpty() && leafNodes.isEmpty()) {
    throw new DetectedCycleException(
        "Graph has nodes, but they represent a cycle with no leaf nodes!");
  }

  final ArrayDeque<ValueNode> nodesToProcess = new ArrayDeque<>();
  nodesToProcess.addAll(leafNodes);

  while (!nodesToProcess.isEmpty()) {
    final ValueNode next = nodesToProcess.pollFirst();
    mSortedNodes.add(next);
    NodeState nodeState = mNodeStates.get(next);
    if (nodeState == null) {
      String message =
          next.getClass().getSimpleName() + " : InputNames " + next.buildDebugInputsString();
      // Added for debugging T67342661
      ComponentsReporter.emitMessage(
          ComponentsReporter.LogLevel.ERROR, STATE_NOT_INTIALIZED_FOR_VALUE_NODE, message);
    }
    for (ValueNode input : next.getAllInputs()) {
      final int outputsLeft = nodesToOutputsLeft.get(input) - 1;
      nodesToOutputsLeft.put(input, outputsLeft);
      if (outputsLeft == 0) {
        nodesToProcess.addLast(input);
      } else if (outputsLeft < 0) {
        throw new DetectedCycleException("Detected cycle.");
      }
    }
  }

  int expectedTotalNodes = nodesToOutputsLeft.size() + leafNodes.size();
  if (mSortedNodes.size() != expectedTotalNodes) {
    throw new DetectedCycleException(
        "Had unreachable nodes in graph -- this likely means there was a cycle");
  }

  Collections.reverse(mSortedNodes);
  mIsDirty = false;
}
 

/**
 * Looks at each action in {@code actionsToCheck} and determines whether additional artifacts,
 * actions, and (in the case of {@link SkyframeAwareAction}s) other Skyframe nodes need to be
 * restarted. If this finds more actions to restart, those actions are recursively checked too.
 */
private void checkActions(
    ImmutableList<ActionAndLookupData> actionsToCheck,
    Environment env,
    MutableGraph<SkyKey> rewindGraph,
    ImmutableList.Builder<Action> additionalActionsToRestart)
    throws InterruptedException {

  ArrayDeque<ActionAndLookupData> uncheckedActions = new ArrayDeque<>(actionsToCheck);
  while (!uncheckedActions.isEmpty()) {
    ActionAndLookupData actionAndLookupData = uncheckedActions.removeFirst();
    ActionLookupData actionKey = actionAndLookupData.lookupData();
    Action action = actionAndLookupData.action();
    ArrayList<Artifact.DerivedArtifact> artifactsToCheck = new ArrayList<>();
    ArrayList<ActionLookupData> newlyDiscoveredActions = new ArrayList<>();

    if (action instanceof SkyframeAwareAction) {
      // This action depends on more than just its input artifact values. We need to also restart
      // the Skyframe subgraph it depends on, up to and including any artifacts, which may
      // aggregate multiple actions.
      addSkyframeAwareDepsAndGetNewlyVisitedArtifactsAndActions(
          rewindGraph,
          actionKey,
          (SkyframeAwareAction) action,
          artifactsToCheck,
          newlyDiscoveredActions);
    }

    if (action.mayInsensitivelyPropagateInputs()) {
      // Restarting this action won't recreate the missing input. We need to also restart this
      // action's non-source inputs and the actions which created those inputs.
      addPropagatingActionDepsAndGetNewlyVisitedArtifactsAndActions(
          rewindGraph, actionKey, action, artifactsToCheck, newlyDiscoveredActions);
    }

    for (ActionLookupData actionLookupData : newlyDiscoveredActions) {
      Action additionalAction =
          checkNotNull(
              ActionUtils.getActionForLookupData(env, actionLookupData), actionLookupData);
      additionalActionsToRestart.add(additionalAction);
      uncheckedActions.add(ActionAndLookupData.create(actionLookupData, additionalAction));
    }
    for (Artifact.DerivedArtifact artifact : artifactsToCheck) {
      Map<ActionLookupData, Action> actionMap = getActionsForLostArtifact(artifact, env);
      if (actionMap == null) {
        continue;
      }
      ImmutableList<ActionAndLookupData> newlyVisitedActions =
          addArtifactDepsAndGetNewlyVisitedActions(rewindGraph, artifact, actionMap);
      additionalActionsToRestart.addAll(actions(newlyVisitedActions));
      uncheckedActions.addAll(newlyVisitedActions);
    }
  }
}
 

/**
 * Iterates over the provided records and tests whether {@link SpanningRecordSerializer} and {@link RecordDeserializer}
 * interact as expected.
 *
 * <p>Only a single {@link MemorySegment} will be allocated.
 *
 * @param records records to test
 * @param segmentSize size for the {@link MemorySegment}
 */
private static void testSerializationRoundTrip(
		Iterable<SerializationTestType> records,
		int segmentSize,
		RecordSerializer<SerializationTestType> serializer,
		RecordDeserializer<SerializationTestType> deserializer)
	throws Exception {
	final ArrayDeque<SerializationTestType> serializedRecords = new ArrayDeque<>();

	// -------------------------------------------------------------------------------------------------------------

	BufferAndSerializerResult serializationResult = setNextBufferForSerializer(serializer, segmentSize);

	int numRecords = 0;
	for (SerializationTestType record : records) {

		serializedRecords.add(record);

		numRecords++;

		// serialize record
		serializer.serializeRecord(record);
		if (serializer.copyToBufferBuilder(serializationResult.getBufferBuilder()).isFullBuffer()) {
			// buffer is full => start deserializing
			deserializer.setNextBuffer(serializationResult.buildBuffer());

			numRecords -= DeserializationUtils.deserializeRecords(serializedRecords, deserializer);

			// move buffers as long as necessary (for long records)
			while ((serializationResult = setNextBufferForSerializer(serializer, segmentSize)).isFullBuffer()) {
				deserializer.setNextBuffer(serializationResult.buildBuffer());
			}
		}
	}

	// deserialize left over records
	deserializer.setNextBuffer(serializationResult.buildBuffer());

	while (!serializedRecords.isEmpty()) {
		SerializationTestType expected = serializedRecords.poll();

		SerializationTestType actual = expected.getClass().newInstance();
		RecordDeserializer.DeserializationResult result = deserializer.getNextRecord(actual);

		Assert.assertTrue(result.isFullRecord());
		Assert.assertEquals(expected, actual);
		numRecords--;
	}

	// assert that all records have been serialized and deserialized
	Assert.assertEquals(0, numRecords);
	Assert.assertFalse(serializer.hasSerializedData());
	Assert.assertFalse(deserializer.hasUnfinishedData());
}
 

/**
 * Parses the text payload of a WebVTT Cue and applies modifications on {@link WebvttCue.Builder}.
 *
 * @param id Id of the cue, {@code null} if it is not present.
 * @param markup The markup text to be parsed.
 * @param styles List of styles defined by the CSS style blocks preceeding the cues.
 * @param builder Output builder.
 */
/* package */ static void parseCueText(String id, String markup, WebvttCue.Builder builder,
    List<WebvttCssStyle> styles) {
  SpannableStringBuilder spannedText = new SpannableStringBuilder();
  ArrayDeque<StartTag> startTagStack = new ArrayDeque<>();
  List<StyleMatch> scratchStyleMatches = new ArrayList<>();
  int pos = 0;
  while (pos < markup.length()) {
    char curr = markup.charAt(pos);
    switch (curr) {
      case CHAR_LESS_THAN:
        if (pos + 1 >= markup.length()) {
          pos++;
          break; // avoid ArrayOutOfBoundsException
        }
        int ltPos = pos;
        boolean isClosingTag = markup.charAt(ltPos + 1) == CHAR_SLASH;
        pos = findEndOfTag(markup, ltPos + 1);
        boolean isVoidTag = markup.charAt(pos - 2) == CHAR_SLASH;
        String fullTagExpression = markup.substring(ltPos + (isClosingTag ? 2 : 1),
            isVoidTag ? pos - 2 : pos - 1);
        String tagName = getTagName(fullTagExpression);
        if (tagName == null || !isSupportedTag(tagName)) {
          continue;
        }
        if (isClosingTag) {
          StartTag startTag;
          do {
            if (startTagStack.isEmpty()) {
              break;
            }
            startTag = startTagStack.pop();
            applySpansForTag(id, startTag, spannedText, styles, scratchStyleMatches);
          } while(!startTag.name.equals(tagName));
        } else if (!isVoidTag) {
          startTagStack.push(StartTag.buildStartTag(fullTagExpression, spannedText.length()));
        }
        break;
      case CHAR_AMPERSAND:
        int semiColonEndIndex = markup.indexOf(CHAR_SEMI_COLON, pos + 1);
        int spaceEndIndex = markup.indexOf(CHAR_SPACE, pos + 1);
        int entityEndIndex = semiColonEndIndex == -1 ? spaceEndIndex
            : (spaceEndIndex == -1 ? semiColonEndIndex
                : Math.min(semiColonEndIndex, spaceEndIndex));
        if (entityEndIndex != -1) {
          applyEntity(markup.substring(pos + 1, entityEndIndex), spannedText);
          if (entityEndIndex == spaceEndIndex) {
            spannedText.append(" ");
          }
          pos = entityEndIndex + 1;
        } else {
          spannedText.append(curr);
          pos++;
        }
        break;
      default:
        spannedText.append(curr);
        pos++;
        break;
    }
  }
  // apply unclosed tags
  while (!startTagStack.isEmpty()) {
    applySpansForTag(id, startTagStack.pop(), spannedText, styles, scratchStyleMatches);
  }
  applySpansForTag(id, StartTag.buildWholeCueVirtualTag(), spannedText, styles,
      scratchStyleMatches);
  builder.setText(spannedText);
}
 

/**
 * Parses FTS options from the create statement of an FTS table.
 *
 * This method assumes the given create statement is a valid well-formed SQLite statement as
 * defined in the <a href="https://www.sqlite.org/lang_createvtab.html">CREATE VIRTUAL TABLE
 * syntax diagram</a>.
 *
 * @param createStatement the "CREATE VIRTUAL TABLE" statement.
 * @return the set of FTS option key and values in the create statement.
 */
@VisibleForTesting
@SuppressWarnings("WeakerAccess") /* synthetic access */
static Set<String> parseOptions(String createStatement) {
    if (createStatement.isEmpty()) {
        return new HashSet<>();
    }

    // Module arguments are within the parenthesis followed by the module name.
    String argsString = createStatement.substring(
            createStatement.indexOf('(') + 1,
            createStatement.lastIndexOf(')'));

    // Split the module argument string by the comma delimiter, keeping track of quotation so
    // so that if the delimiter is found within a string literal we don't substring at the wrong
    // index. SQLite supports four ways of quoting keywords, see:
    // https://www.sqlite.org/lang_keywords.html
    List<String> args = new ArrayList<>();
    ArrayDeque<Character> quoteStack = new ArrayDeque<>();
    int lastDelimiterIndex = -1;
    for (int i = 0; i < argsString.length(); i++) {
        char c = argsString.charAt(i);
        switch (c) {
            case '\'':
            case '"':
            case '`':
                if (quoteStack.isEmpty()) {
                    quoteStack.push(c);
                } else if (quoteStack.peek() == c) {
                    quoteStack.pop();
                }
                break;
            case '[':
                if (quoteStack.isEmpty()) {
                    quoteStack.push(c);
                }
                break;
            case ']':
                if (!quoteStack.isEmpty() && quoteStack.peek() == '[') {
                    quoteStack.pop();
                }
                break;
            case ',':
                if (quoteStack.isEmpty()) {
                    args.add(argsString.substring(lastDelimiterIndex + 1, i).trim());
                    lastDelimiterIndex = i;
                }
                break;
        }
    }
    args.add(argsString.substring(lastDelimiterIndex + 1).trim()); // Add final argument.

    // Match args against valid options, otherwise they are column definitions.
    HashSet<String> options = new HashSet<>();
    for (String arg : args) {
        for (String validOption : FTS_OPTIONS) {
            if (arg.startsWith(validOption)) {
                options.add(arg);
            }
        }
    }

    return options;
}
 

private boolean nearbyUpstream(ArrayDeque<VcfRecord> regions, int start) {
  return !regions.isEmpty() && start < regions.peekLast().getEnd() + mDistance;
}