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Unified Diff: dart/sdk/lib/_collection_dev/iterable.dart

Issue 12296011: Version 0.3.7.4 (Closed) Base URL: http://dart.googlecode.com/svn/trunk/
Patch Set: Created 7 years, 10 months ago
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Index: dart/sdk/lib/_collection_dev/iterable.dart
===================================================================
--- dart/sdk/lib/_collection_dev/iterable.dart (revision 18634)
+++ dart/sdk/lib/_collection_dev/iterable.dart (working copy)
@@ -4,7 +4,6 @@
part of dart._collection.dev;
-
/**
* An [Iterable] for classes that have efficient [length] and [elementAt].
*
@@ -15,7 +14,7 @@
int get length;
E elementAt(int i);
- Iterator<E> get iterator => new ListIterableIterator<E>(this);
+ Iterator<E> get iterator => new ListIterator<E>(this);
void forEach(void action(E element)) {
int length = this.length;
@@ -93,7 +92,7 @@
E lastMatching(bool test(E element), { E orElse() }) {
int length = this.length;
- for (int i = length - 1; i >= 0; i++) {
+ for (int i = length - 1; i >= 0; i--) {
E element = elementAt(i);
if (test(element)) return element;
if (length != this.length) {
@@ -196,15 +195,13 @@
Iterable<E> where(bool test(E element)) => super.where(test);
- Iterable map(f(E element)) => new MappedIterable(this, f);
+ Iterable map(f(E element)) => new MappedListIterable(this, f);
- Iterable mappedBy(f(E element)) => super.mappedBy(f);
-
reduce(var initialValue, combine(var previousValue, E element)) {
var value = initialValue;
int length = this.length;
for (int i = 0; i < length; i++) {
- value = reduce(value, elementAt(i));
+ value = combine(value, elementAt(i));
if (length != this.length) {
throw new ConcurrentModificationError(this);
}
@@ -237,7 +234,7 @@
}
}
-abstract class SubListIterable<E> extends ListIterable<E> {
+class SubListIterable<E> extends ListIterable<E> {
final Iterable<E> _iterable;
final int _start;
/** If null, represents the length of the iterable. */
@@ -284,19 +281,27 @@
if (_endOrLength == null) {
return new SubListIterable(_iterable, _start, _start + count);
} else {
- newEnd = _start + count;
+ int newEnd = _start + count;
if (_endOrLength < newEnd) return this;
return new SubListIterable(_iterable, _start, newEnd);
}
}
}
-class ListIterableIterator<E> implements Iterator<E> {
+/**
+ * An [Iterator] that iterates a list-like [Iterable].
+ *
+ * All iterations is done in terms of [Iterable.length] and
+ * [Iterable.elementAt]. These operations are fast for list-like
+ * iterables.
+ */
+class ListIterator<E> implements Iterator<E> {
final Iterable<E> _iterable;
final int _length;
int _index;
E _current;
- ListIterableIterator(Iterable<E> iterable)
+
+ ListIterator(Iterable<E> iterable)
: _iterable = iterable, _length = iterable.length, _index = 0;
E get current => _current;
@@ -330,9 +335,14 @@
// Length related functions are independent of the mapping.
int get length => _iterable.length;
bool get isEmpty => _iterable.isEmpty;
+
+ // Index based lookup can be done before transforming.
+ T get first => _f(_iterable.first);
+ T get last => _f(_iterable.last);
+ T get single => _f(_iterable.single);
+ T elementAt(int index) => _f(_iterable.elementAt(index));
}
-
class MappedIterator<S, T> extends Iterator<T> {
T _current;
final Iterator<S> _iterator;
@@ -346,345 +356,28 @@
if (_iterator.moveNext()) {
_current = _f(_iterator.current);
return true;
- } else {
- _current = null;
- return false;
}
+ _current = null;
+ return false;
}
T get current => _current;
}
/** Specialized alternative to [MappedIterable] for mapped [List]s. */
-class MappedListIterable<S, T> extends Iterable<T> {
- final List<S> _list;
- /**
- * Start index of the part of the list to map.
- *
- * Allows mapping only a sub-list of an existing list.
- *
- * Used to implement lazy skip/take on a [MappedListIterable].
- */
- final int _start;
-
- /**
- * End index of the part of the list to map.
- *
- * If null, always use the length of the list.
- */
- final int _end;
-
+class MappedListIterable<S, T> extends ListIterable<T> {
+ final Iterable<S> _source;
// TODO(ahe): Restore type when feature is implemented in dart2js
// checked mode. http://dartbug.com/7733
final /* _Transformation<S, T> */ _f;
- MappedListIterable(this._list, T this._f(S element), this._start, this._end) {
- if (_end != null && _end < _start) {
- throw new ArgumentError("End ($_end) before start ($_start)");
- }
- }
+ MappedListIterable(this._source, T this._f(S value));
- /** The start index, limited to the current length of the list. */
- int get _startIndex {
- if (_start <= _list.length) return _start;
- return _list.length;
- }
-
- /** The end index, if given, limited to the current length of the list. */
- int get _endIndex {
- if (_end == null || _end > _list.length) return _list.length;
- return _end;
- }
-
- Iterator<T> get iterator =>
- new MappedListIterator<S, T>(_list, _f, _startIndex, _endIndex);
-
- void forEach(void action(T element)) {
- int length = _list.length;
- for (int i = _startIndex, n = _endIndex; i < n; i++) {
- action(_f(_list[i]));
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- }
-
- bool get isEmpty => _startIndex == _endIndex;
-
- int get length => _endIndex - _startIndex;
-
- T get first {
- int start = _startIndex;
- if (start == _endIndex) {
- throw new StateError("No elements");
- }
- return _f(_list.elementAt(start));
- }
-
- T get last {
- int end = _endIndex;
- if (end == _startIndex) {
- throw new StateError("No elements");
- }
- return _f(_list.elementAt(end - 1));
- }
-
- T get single {
- int start = _startIndex;
- int end = _endIndex;
- if (start != end - 1) {
- if (start == end) {
- throw new StateError("No elements");
- }
- throw new StateError("Too many elements");
- }
- return _f(_list[start]);
- }
-
- T elementAt(int index) {
- index += _startIndex;
- if (index >= _endIndex) {
- throw new StateError("No matching element");
- }
- return _f(_list.elementAt(index));
- }
-
- bool contains(T element) {
- int length = _list.length;
- for (int i = _startIndex, n = _endIndex; i < n; i++) {
- if (_f(_list[i]) == element) {
- return true;
- }
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- return false;
- }
-
- bool every(bool test(T element)) {
- int length = _list.length;
- for (int i = _startIndex, n = _endIndex; i < n; i++) {
- if (!test(_f(_list[i]))) return false;
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- return true;
- }
-
- bool any(bool test(T element)) {
- int length = _list.length;
- for (int i = _startIndex, n = _endIndex; i < n; i++) {
- if (test(_f(_list[i]))) return true;
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- return false;
- }
-
- T firstMatching(bool test(T element), { T orElse() }) {
- int length = _list.length;
- for (int i = _startIndex, n = _endIndex; i < n; i++) {
- T value = _f(_list[i]);
- if (test(value)) return value;
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- if (orElse != null) return orElse();
- throw new StateError("No matching element");
- }
-
- T lastMatching(bool test(T element), { T orElse() }) {
- int length = _list.length;
- for (int i = _endIndex - 1, start = _startIndex; i >= start; i++) {
- T value = _f(_list[i]);
- if (test(value)) return value;
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- if (orElse != null) return orElse();
- throw new StateError("No matching element");
- }
-
- T singleMatching(bool test(T element)) {
- int length = _list.length;
- T match;
- bool matchFound = false;
- for (int i = _startIndex, n = _endIndex; i < n; i++) {
- T value = _f(_list[i]);
- if (test(value)) {
- if (matchFound) {
- throw new StateError("More than one matching element");
- }
- matchFound = true;
- match = value;
- }
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- if (matchFound) return match;
- throw new StateError("No matching element");
- }
-
- T min([int compare(T a, T b)]) {
- if (compare == null) {
- var defaultCompare = Comparable.compare;
- compare = defaultCompare;
- }
- int length = _list.length;
- int start = _startIndex;
- int end = _endIndex;
- if (start == end) return null;
- T value = _f(_list[start]);
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- for (int i = start + 1; i < end; i++) {
- T nextValue = _f(_list[i]);
- if (compare(value, nextValue) > 0) {
- value = nextValue;
- }
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- return value;
- }
-
- T max([int compare(T a, T b)]) {
- if (compare == null) {
- var defaultCompare = Comparable.compare;
- compare = defaultCompare;
- }
- int length = _list.length;
- int start = _startIndex;
- int end = _endIndex;
- if (start == end) return null;
- T value = _f(_list[start]);
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- for (int i = start + 1; i < end; i++) {
- T nextValue = _f(_list[i]);
- if (compare(value, nextValue) < 0) {
- value = nextValue;
- }
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- return value;
- }
-
- String join([String separator]) {
- int start = _startIndex;
- int end = _endIndex;
- if (start == end) return "";
- StringBuffer buffer = new StringBuffer("${_f(_list[start])}");
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- for (int i = start + 1; i < end; i++) {
- if (separator != null && separator != "") {
- buffer.add(separator);
- }
- buffer.add("${_f(_list[i])}");
- if (_list.length != length) {
- throw new ConcurrentModificationError(_list);
- }
- }
- return buffer.toString();
- }
-
- Iterable<T> where(bool test(T element)) => super.where(test);
-
- Iterable map(f(T element)) {
- return new MappedListIterable(_list, (S v) => f(_f(v)), _start, _end);
- }
-
- Iterable mappedBy(f(T element)) => map(f);
-
- reduce(var initialValue, combine(var previousValue, T element)) {
- return _list.reduce(initialValue, (v, S e) => combine(v, _f(e)));
- }
-
- Iterable<T> skip(int count) {
- int start = _startIndex + count;
- if (_end != null && start >= _end) {
- return new EmptyIterable<T>();
- }
- return new MappedListIterable(_list, _f, start, _end);
- }
-
- Iterable<T> skipWhile(bool test(T element)) => super.skipWhile(test);
-
- Iterable<T> take(int count) {
- int newEnd = _start + count;
- if (_end == null || newEnd < _end) {
- return new MappedListIterable(_list, _f, _start, newEnd);
- }
- // Equivalent to "this".
- return new MappedListIterable(_list, _f, _start, _end);
- }
-
- Iterable<T> takeWhile(bool test(T element)) => super.takeWhile(test);
-
- List<T> toList() {
- List<T> result = new List<T>();
- forEach(result.add);
- return result;
- }
-
- Set<T> toSet() {
- Set<T> result = new Set<T>();
- forEach(result.add);
- return result;
- }
+ int get length => _source.length;
+ T elementAt(int index) => _f(_source.elementAt(index));
}
-/**
- * Iterator for [MappedListIterable].
- *
- * A list iterator that iterates over (a sublist of) a list and
- * returns the values transformed by a function.
- *
- * As a list iterator, it throws if the length of the list has
- * changed during iteration.
- */
-class MappedListIterator<S, T> implements Iterator<T> {
- List<S> _list;
- // TODO(ahe): Restore type when feature is implemented in dart2js
- // checked mode. http://dartbug.com/7733
- final /* _Transformation<S, T> */ _f;
- final int _endIndex;
- final int _length;
- int _index;
- T _current;
- MappedListIterator(List<S> list, this._f, int start, this._endIndex)
- : _list = list, _length = list.length, _index = start;
-
- T get current => _current;
-
- bool moveNext() {
- if (_list.length != _length) {
- throw new ConcurrentModificationError(_list);
- }
- if (_index >= _endIndex) {
- _current = null;
- return false;
- }
- _current = _f(_list[_index]);
- _index++;
- return true;
- }
-}
-
typedef bool _ElementPredicate<E>(E element);
class WhereIterable<E> extends Iterable<E> {
@@ -969,8 +662,6 @@
Iterable map(f(E element)) => const EmptyIterable();
- Iterable mappedBy(f(E element)) => const EmptyIterable();
-
reduce(var initialValue, combine(var previousValue, E element)) {
return initialValue;
}
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