part of dart.collection;
 abstract class Queue<E> implements Iterable<E>, EfficientLength {factory Queue() = ListQueue<E>;
 factory Queue.from(Iterable elements) = ListQueue<E>.from;
 E removeFirst();
 E removeLast();
 void addFirst(E value);
 void addLast(E value);
 void add(E value);
 bool remove(Object object);
 void addAll(Iterable<E> iterable);
 void removeWhere(bool test(E element));
 void retainWhere(bool test(E element));
 void clear();
}
 class DoubleLinkedQueueEntry<E> {DoubleLinkedQueueEntry<E> _previous;
 DoubleLinkedQueueEntry<E> _next;
 E _element;
 DoubleLinkedQueueEntry(E e) : _element = e;
 void _link(DoubleLinkedQueueEntry<E> previous, DoubleLinkedQueueEntry<E> next) {
_next = next;
 _previous = previous;
 previous._next = this;
 next._previous = this;
}
 void append(E e) {
new DoubleLinkedQueueEntry<E>(e)._link(this, _next);
}
 void prepend(E e) {
new DoubleLinkedQueueEntry<E>(e)._link(_previous, this);
}
 E remove() {
_previous._next = _next;
 _next._previous = _previous;
 _next = null;
 _previous = null;
 return _element;
}
 DoubleLinkedQueueEntry<E> _asNonSentinelEntry() {
return this;
}
 DoubleLinkedQueueEntry<E> previousEntry() {
return _previous._asNonSentinelEntry();
}
 DoubleLinkedQueueEntry<E> nextEntry() {
return _next._asNonSentinelEntry();
}
 E get element {
return _element;
}
 void set element(E e) {
_element = e;
}
}
 class _DoubleLinkedQueueEntrySentinel<E> extends DoubleLinkedQueueEntry<E> {_DoubleLinkedQueueEntrySentinel() : super(null) {
_link(this, this);
}
 E remove() {
throw IterableElementError.noElement();
}
 DoubleLinkedQueueEntry<E> _asNonSentinelEntry() {
return null;
}
 void set element(E e) {
assert (false);}
 E get element {
throw IterableElementError.noElement();
}
}
 class DoubleLinkedQueue<E> extends IterableBase<E> implements Queue<E> {_DoubleLinkedQueueEntrySentinel<E> _sentinel;
 int _elementCount = 0;
 DoubleLinkedQueue() {
_sentinel = new _DoubleLinkedQueueEntrySentinel<E>();
}
 factory DoubleLinkedQueue.from(Iterable elements) {
Queue<E> list = new DoubleLinkedQueue<E>();
 for (final E e in DEVC$RT.cast(elements, DEVC$RT.type((Iterable<dynamic> _) {
}
), DEVC$RT.type((Iterable<E> _) {
}
), "CompositeCast", """line 208, column 23 of dart:collection/queue.dart: """, elements is Iterable<E>, false)) {
list.addLast(e);
}
 return DEVC$RT.cast(list, DEVC$RT.type((Queue<E> _) {
}
), DEVC$RT.type((DoubleLinkedQueue<E> _) {
}
), "CompositeCast", """line 211, column 12 of dart:collection/queue.dart: """, list is DoubleLinkedQueue<E>, false);
}
 int get length => _elementCount;
 void addLast(E value) {
_sentinel.prepend(value);
 _elementCount++;
}
 void addFirst(E value) {
_sentinel.append(value);
 _elementCount++;
}
 void add(E value) {
_sentinel.prepend(value);
 _elementCount++;
}
 void addAll(Iterable<E> iterable) {
for (final E value in iterable) {
_sentinel.prepend(value);
 _elementCount++;
}
}
 E removeLast() {
E result = _sentinel._previous.remove();
 _elementCount--;
 return result;
}
 E removeFirst() {
E result = _sentinel._next.remove();
 _elementCount--;
 return result;
}
 bool remove(Object o) {
DoubleLinkedQueueEntry<E> entry = _sentinel._next;
 while (!identical(entry, _sentinel)) {
if (entry.element == o) {
entry.remove();
 _elementCount--;
 return true;
}
 entry = entry._next;
}
 return false;
}
 void _filter(bool test(E element), bool removeMatching) {
DoubleLinkedQueueEntry<E> entry = _sentinel._next;
 while (!identical(entry, _sentinel)) {
DoubleLinkedQueueEntry<E> next = entry._next;
 if (identical(removeMatching, test(entry.element))) {
entry.remove();
 _elementCount--;
}
 entry = next;
}
}
 void removeWhere(bool test(E element)) {
_filter(test, true);
}
 void retainWhere(bool test(E element)) {
_filter(test, false);
}
 E get first {
return _sentinel._next.element;
}
 E get last {
return _sentinel._previous.element;
}
 E get single {
if (identical(_sentinel._next, _sentinel._previous)) {
return _sentinel._next.element;
}
 throw IterableElementError.tooMany();
}
 DoubleLinkedQueueEntry<E> lastEntry() {
return _sentinel.previousEntry();
}
 DoubleLinkedQueueEntry<E> firstEntry() {
return _sentinel.nextEntry();
}
 bool get isEmpty {
return (identical(_sentinel._next, _sentinel));
}
 void clear() {
_sentinel._next = _sentinel;
 _sentinel._previous = _sentinel;
 _elementCount = 0;
}
 void forEachEntry(void f(DoubleLinkedQueueEntry<E> element)) {
DoubleLinkedQueueEntry<E> entry = _sentinel._next;
 while (!identical(entry, _sentinel)) {
DoubleLinkedQueueEntry<E> nextEntry = entry._next;
 f(entry);
 entry = nextEntry;
}
}
 _DoubleLinkedQueueIterator<E> get iterator {
return new _DoubleLinkedQueueIterator<E>(_sentinel);
}
 String toString() => IterableBase.iterableToFullString(this, '{', '}');
}
 class _DoubleLinkedQueueIterator<E> implements Iterator<E> {_DoubleLinkedQueueEntrySentinel<E> _sentinel;
 DoubleLinkedQueueEntry<E> _nextEntry = null;
 E _current;
 _DoubleLinkedQueueIterator(_DoubleLinkedQueueEntrySentinel<E> sentinel) : _sentinel = sentinel, _nextEntry = sentinel._next;
 bool moveNext() {
if (!identical(_nextEntry, _sentinel)) {
_current = _nextEntry._element;
 _nextEntry = _nextEntry._next;
 return true;
}
 _current = null;
 _nextEntry = _sentinel = null;
 return false;
}
 E get current => _current;
}
 class ListQueue<E> extends IterableBase<E> implements Queue<E> {static const int _INITIAL_CAPACITY = 8;
 List<E> _table;
 int _head;
 int _tail;
 int _modificationCount = 0;
 ListQueue([int initialCapacity]) : _head = 0, _tail = 0 {
if (initialCapacity == null || initialCapacity < _INITIAL_CAPACITY) {
initialCapacity = _INITIAL_CAPACITY;
}
 else if (!_isPowerOf2(initialCapacity)) {
initialCapacity = _nextPowerOf2(initialCapacity);
}
 assert (_isPowerOf2(initialCapacity)); _table = new List<E>(initialCapacity);
}
 factory ListQueue.from(Iterable elements) {
if (elements is List) {
int length = elements.length;
 ListQueue<E> queue = new ListQueue<E>(length + 1);
 assert (queue._table.length > length); List sourceList = elements;
 queue._table.setRange(0, length, DEVC$RT.cast(sourceList, DEVC$RT.type((List<dynamic> _) {
}
), DEVC$RT.type((Iterable<E> _) {
}
), "CompositeCast", """line 402, column 40 of dart:collection/queue.dart: """, sourceList is Iterable<E>, false), 0);
 queue._tail = length;
 return queue;
}
 else {
int capacity = _INITIAL_CAPACITY;
 if (elements is EfficientLength) {
capacity = elements.length;
}
 ListQueue<E> result = new ListQueue<E>(capacity);
 for (final E element in DEVC$RT.cast(elements, DEVC$RT.type((Iterable<dynamic> _) {
}
), DEVC$RT.type((Iterable<E> _) {
}
), "CompositeCast", """line 411, column 31 of dart:collection/queue.dart: """, elements is Iterable<E>, false)) {
result.addLast(element);
}
 return result;
}
}
 Iterator<E> get iterator => new _ListQueueIterator<E>(this);
 void forEach(void action(E element)) {
int modificationCount = _modificationCount;
 for (int i = _head; i != _tail; i = (i + 1) & (_table.length - 1)) {
action(_table[i]);
 _checkModification(modificationCount);
}
}
 bool get isEmpty => _head == _tail;
 int get length => (_tail - _head) & (_table.length - 1);
 E get first {
if (_head == _tail) throw IterableElementError.noElement();
 return _table[_head];
}
 E get last {
if (_head == _tail) throw IterableElementError.noElement();
 return _table[(_tail - 1) & (_table.length - 1)];
}
 E get single {
if (_head == _tail) throw IterableElementError.noElement();
 if (length > 1) throw IterableElementError.tooMany();
 return _table[_head];
}
 E elementAt(int index) {
RangeError.checkValidIndex(index, this);
 return _table[(_head + index) & (_table.length - 1)];
}
 List<E> toList({
bool growable : true}
) {
List<E> list;
 if (growable) {
list = new List<E>()..length = length;
}
 else {
list = new List<E>(length);
}
 _writeToList(list);
 return list;
}
 void add(E element) {
_add(element);
}
 void addAll(Iterable<E> elements) {
if (elements is List) {
List list = DEVC$RT.cast(elements, DEVC$RT.type((Iterable<E> _) {
}
), DEVC$RT.type((List<dynamic> _) {
}
), "AssignmentCast", """line 474, column 19 of dart:collection/queue.dart: """, elements is List<dynamic>, true);
 int addCount = list.length;
 int length = this.length;
 if (length + addCount >= _table.length) {
_preGrow(length + addCount);
 _table.setRange(length, length + addCount, DEVC$RT.cast(list, DEVC$RT.type((List<dynamic> _) {
}
), DEVC$RT.type((Iterable<E> _) {
}
), "CompositeCast", """line 480, column 52 of dart:collection/queue.dart: """, list is Iterable<E>, false), 0);
 _tail += addCount;
}
 else {
int endSpace = _table.length - _tail;
 if (addCount < endSpace) {
_table.setRange(_tail, _tail + addCount, DEVC$RT.cast(list, DEVC$RT.type((List<dynamic> _) {
}
), DEVC$RT.type((Iterable<E> _) {
}
), "CompositeCast", """line 486, column 52 of dart:collection/queue.dart: """, list is Iterable<E>, false), 0);
 _tail += addCount;
}
 else {
int preSpace = addCount - endSpace;
 _table.setRange(_tail, _tail + endSpace, DEVC$RT.cast(list, DEVC$RT.type((List<dynamic> _) {
}
), DEVC$RT.type((Iterable<E> _) {
}
), "CompositeCast", """line 490, column 52 of dart:collection/queue.dart: """, list is Iterable<E>, false), 0);
 _table.setRange(0, preSpace, DEVC$RT.cast(list, DEVC$RT.type((List<dynamic> _) {
}
), DEVC$RT.type((Iterable<E> _) {
}
), "CompositeCast", """line 491, column 40 of dart:collection/queue.dart: """, list is Iterable<E>, false), endSpace);
 _tail = preSpace;
}
}
 _modificationCount++;
}
 else {
for (E element in elements) _add(element);
}
}
 bool remove(Object object) {
for (int i = _head; i != _tail; i = (i + 1) & (_table.length - 1)) {
E element = _table[i];
 if (element == object) {
_remove(i);
 _modificationCount++;
 return true;
}
}
 return false;
}
 void _filterWhere(bool test(E element), bool removeMatching) {
int index = _head;
 int modificationCount = _modificationCount;
 int i = _head;
 while (i != _tail) {
E element = _table[i];
 bool remove = identical(removeMatching, test(element));
 _checkModification(modificationCount);
 if (remove) {
i = _remove(i);
 modificationCount = ++_modificationCount;
}
 else {
i = (i + 1) & (_table.length - 1);
}
}
}
 void removeWhere(bool test(E element)) {
_filterWhere(test, true);
}
 void retainWhere(bool test(E element)) {
_filterWhere(test, false);
}
 void clear() {
if (_head != _tail) {
for (int i = _head; i != _tail; i = (i + 1) & (_table.length - 1)) {
_table[i] = null;
}
 _head = _tail = 0;
 _modificationCount++;
}
}
 String toString() => IterableBase.iterableToFullString(this, "{", "}");
 void addLast(E element) {
_add(element);
}
 void addFirst(E element) {
_head = (_head - 1) & (_table.length - 1);
 _table[_head] = element;
 if (_head == _tail) _grow();
 _modificationCount++;
}
 E removeFirst() {
if (_head == _tail) throw IterableElementError.noElement();
 _modificationCount++;
 E result = _table[_head];
 _table[_head] = null;
 _head = (_head + 1) & (_table.length - 1);
 return result;
}
 E removeLast() {
if (_head == _tail) throw IterableElementError.noElement();
 _modificationCount++;
 _tail = (_tail - 1) & (_table.length - 1);
 E result = _table[_tail];
 _table[_tail] = null;
 return result;
}
 static bool _isPowerOf2(int number) => (number & (number - 1)) == 0;
 static int _nextPowerOf2(int number) {
assert (number > 0); number = (number << 1) - 1;
 for (;;) {
int nextNumber = number & (number - 1);
 if (nextNumber == 0) return number;
 number = nextNumber;
}
}
 void _checkModification(int expectedModificationCount) {
if (expectedModificationCount != _modificationCount) {
throw new ConcurrentModificationError(this);
}
}
 void _add(E element) {
_table[_tail] = element;
 _tail = (_tail + 1) & (_table.length - 1);
 if (_head == _tail) _grow();
 _modificationCount++;
}
 int _remove(int offset) {
int mask = _table.length - 1;
 int startDistance = (offset - _head) & mask;
 int endDistance = (_tail - offset) & mask;
 if (startDistance < endDistance) {
int i = offset;
 while (i != _head) {
int prevOffset = (i - 1) & mask;
 _table[i] = _table[prevOffset];
 i = prevOffset;
}
 _table[_head] = null;
 _head = (_head + 1) & mask;
 return (offset + 1) & mask;
}
 else {
_tail = (_tail - 1) & mask;
 int i = offset;
 while (i != _tail) {
int nextOffset = (i + 1) & mask;
 _table[i] = _table[nextOffset];
 i = nextOffset;
}
 _table[_tail] = null;
 return offset;
}
}
 void _grow() {
List<E> newTable = new List<E>(_table.length * 2);
 int split = _table.length - _head;
 newTable.setRange(0, split, _table, _head);
 newTable.setRange(split, split + _head, _table, 0);
 _head = 0;
 _tail = _table.length;
 _table = newTable;
}
 int _writeToList(List<E> target) {
assert (target.length >= length); if (_head <= _tail) {
int length = _tail - _head;
 target.setRange(0, length, _table, _head);
 return length;
}
 else {
int firstPartSize = _table.length - _head;
 target.setRange(0, firstPartSize, _table, _head);
 target.setRange(firstPartSize, firstPartSize + _tail, _table, 0);
 return _tail + firstPartSize;
}
}
 void _preGrow(int newElementCount) {
assert (newElementCount >= length); newElementCount += newElementCount >> 1;
 int newCapacity = _nextPowerOf2(newElementCount);
 List<E> newTable = new List<E>(newCapacity);
 _tail = _writeToList(newTable);
 _table = newTable;
 _head = 0;
}
}
 class _ListQueueIterator<E> implements Iterator<E> {final ListQueue _queue;
 final int _end;
 final int _modificationCount;
 int _position;
 E _current;
 _ListQueueIterator(ListQueue queue) : _queue = queue, _end = queue._tail, _modificationCount = queue._modificationCount, _position = queue._head;
 E get current => _current;
 bool moveNext() {
_queue._checkModification(_modificationCount);
 if (_position == _end) {
_current = null;
 return false;
}
 _current = ((__x11) => DEVC$RT.cast(__x11, dynamic, E, "CompositeCast", """line 738, column 16 of dart:collection/queue.dart: """, __x11 is E, false))(_queue._table[_position]);
 _position = (_position + 1) & (_queue._table.length - 1);
 return true;
}
}