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-rw-r--r-- | tests/pos/Iter2.scala | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/tests/pos/Iter2.scala b/tests/pos/Iter2.scala new file mode 100644 index 000000000..b9dc5d625 --- /dev/null +++ b/tests/pos/Iter2.scala @@ -0,0 +1,245 @@ +package dotty1.collections +package immutable + +import annotation.unchecked.uncheckedVariance + +object Iter2 { + + trait Iterator[+A] extends IterableOnce[A] { + def hasNext: Boolean + def next: A + def iterator = this + def foreach(f: A => Unit): Unit = ??? + def map[B](f: A => B): Iterator[B] = ??? + def flatMap[B](f: A => IterableOnce[B]): Iterator[B] = ??? + def ++[B >: A](xs: IterableOnce[B]): Iterator[B] = ??? + def drop(n: Int): Iterator[A] = ??? + def indexWhere(p: A => Boolean): Int = { + var i = 0 + while (hasNext) { + if (p(next)) return i + i += 1 + } + -1 + } + def zip[B](that: Iterator[B]): Iterator[(A, B)] = ??? + def copy: Iterator[A] = ??? + } +/* + trait View[+A] { self => + def iterator: Iterator[A] + def foreach(f: A => Unit): Unit = iterator.foreach(f) + def map[B](f: A => B): View[B] = + new View[B] { def iterator = self.iterator.map(f) } + def flatMap[B](f: A => IterableOnce[B]): View[B] = + new View[B] { def iterator = self.iterator.flatMap(f) } + def ++[B >: A](xs: IterableOnce[B]): View[B] = + new View[B] { def iteratpr = self.iterator ++ xs } + def drop(n: Int): View[A] = + new View[A] { def iteratpr = self.iterator.drop(n) } + def indexWhere(p: A => Boolean): Int = { + var i = 0 + while (hasNext) { + if (p(next)) return i + i += 1 + } + -1 + } + def zip[B](that: Iterator[B]): Iterator[(A, B)] = ??? + } +*/ + + trait IterableOnce[+A] { + def iterator: Iterator[A] + def buildIterator: Iterator[A] = iterator + } + + trait FromIterator[+C[X] <: Iterable[X]] { + def fromIterator[B](it: Iterator[B]): C[B] + } + + trait Iterable[+IA] extends IterableOnce[IA] with FromIterator[Iterable] { + def view: View[IA] = new View(iterator) + } + + trait Seq[+AA] extends Iterable[AA] with FromIterator[Seq] { + def apply(i: Int): AA + def length: Int + } + + sealed trait List[+A] extends Seq[A] with FromIterator[List] { + def isEmpty: Boolean + def head: A + def tail: List[A] + def iterator = new ListIterator[A](this) + def fromIterator[B](it: Iterator[B]): List[B] = it match { + case ListIterator(xs) => xs + case _ => if (it.hasNext) Cons(it.next, fromIterator(it)) else Nil + } + def apply(i: Int): A = { + require(!isEmpty) + if (i == 0) head else tail.apply(i - 1) + } + def length: Int = + if (isEmpty) 0 else 1 + tail.length + } + + class View[+A](it: Iterator[A]) extends Iterable[A] with FromIterator[View] { + def iterator: Iterator[A] = it.copy + def fromIterator[B](it: Iterator[B]): View[B] = new View(it) + } + + case class Cons[+A](x: A, xs: List[A]) extends List[A] { + def isEmpty = false + def head = x + def tail = xs + } + + case object Nil extends List[Nothing] { + def isEmpty = true + def head = ??? + def tail = ??? + } + + class ArrayBuffer[A] private (initElems: Array[AnyRef], initLen: Int) extends Seq[A] with FromIterator[ArrayBuffer] { + def this() = this(new Array[AnyRef](16), 0) + def this(it: ArrayIterator[A]) = this(it.elems, it.len) + private var elems: Array[AnyRef] = initElems + private var len = 0 + def iterator = + elems.iterator.take(len).asInstanceOf[Iterator[A]] + override def buildIterator = + new ArrayIterator(elems, len).asInstanceOf[Iterator[A]] + def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] = + new ArrayBuffer(ArrayIterator.fromIterator(it)) + def apply(i: Int) = elems(i).asInstanceOf[A] + def length = len + } +/* + class SeqView[A](itf: () => Iterator) extends Seq[A] with FromIterator[SeqView] { + def iterator = it + def buildIterator = it + def fromIterator[B](it: Iterator[B]) = it match { + case ViewIterator(itf) => SeqView(itf) + } + } +*/ + implicit class IterableTransforms[A, C[X] <: Iterable[X]](val c: Iterable[A] with FromIterator[C]) extends AnyVal { + def map[B](f: A => B): C[B] = c.fromIterator(c.buildIterator.map(f)) + def flatMap[B](f: A => IterableOnce[B]): C[B] = c.fromIterator(c.buildIterator.flatMap(f(_).buildIterator)) + def ++[B >: A](xs: IterableOnce[B]): C[B] = c.fromIterator(c.buildIterator ++ xs.buildIterator) + def drop(n: Int): C[A] = c.fromIterator(c.buildIterator.drop(n)) + def head: A = c.iterator.next + def zip[B](xs: IterableOnce[B]): C[(A, B)] = c.fromIterator(c.iterator.zip(xs.iterator)) + } + + implicit class SeqTransforms[SA, C[X] <: Seq[X]](val c: Seq[SA] with FromIterator[C]) extends AnyVal { + def reverse: C[SA] = { + val elems = new Array[AnyRef](c.length) + var i = elems.length + val it = c.iterator + while (it.hasNext) { + i -= 1 + elems(i) = it.next.asInstanceOf[AnyRef] + } + val xzz = c.fromIterator(ArrayIterator[SA](elems, c.length)) + xzz + } + def indexWhere(p: SA => Boolean): Int = c.iterator.indexWhere(p) + } +/* + case class ViewIterator[+A](itf: () => Iterator) extends Iterator[A] { + + def hasNext = it.hasNext + def next + def map(f: A => B): ViewIterator[B] = ViewIterator(() => it().map(f)) + def + } +*/ + case class ListIterator[+A](xs: List[A]) extends Iterator[A] { + private[this] var current: List[A] = xs + def hasNext = !current.isEmpty + def next = { val res = current.head; current = current.tail; res } + } + + case class ArrayIterator[+A](elems: Array[AnyRef], len: Int) extends Iterator[A] { + import ArrayIterator._ + + private def elem(i: Int) = elems(i).asInstanceOf[A] + + private var cur = 0 + + def hasNext = cur < len + def next = { val res = elem(cur); cur += 1; res } + + override def foreach(f: A => Unit): Unit = + for (i <- 0 until len) f(elem(i)) + + override def map[B](f: A => B): ArrayIterator[B] = { + var mapped = elems + for (i <- 0 until len) { + val x = elem(i) + val y = widen(f(x)) + if (widen(x) ne y) { + if (mapped eq elems) mapped = new Array[AnyRef](len) + mapped(i) = y + } + } + if (mapped eq elems) this.asInstanceOf[ArrayIterator[B]] + else new ArrayIterator(mapped, len) + } + + override def flatMap[B](f: A => IterableOnce[B]): ArrayIterator[B] = + flatten(map(f(_).buildIterator)) + + override def ++[B >: A](that: IterableOnce[B]): ArrayIterator[B] = { + val thatIterator @ ArrayIterator(elems2, len2) = fromIterator(that.iterator) + if (len == 0) thatIterator + else if (len2 == 0) this + else { + val resLen = len + len2 + val resElems = new Array[AnyRef](resLen) + Array.copy(elems, 0, resElems, 0, len) + Array.copy(elems2, 0, resElems, len, len2) + new ArrayIterator(resElems, resLen) + } + } + } + + object ArrayIterator { + private def widen(x: Any): AnyRef = x.asInstanceOf[AnyRef] + + def fromIterator[A](it: Iterator[A]): ArrayIterator[A] = it match { + case it: ArrayIterator[A] => it + case _ => + var elems = new Array[AnyRef](32) + var len = 0 + def ensureCapacity() = { + while (len > elems.length) { + val newElems = new Array[AnyRef](elems.length * 2) + Array.copy(elems, 0, newElems, 0, elems.length) + elems = newElems + } + } + while (it.hasNext) { + len += 1 + ensureCapacity() + elems(len - 1) = widen(it.next) + } + ArrayIterator(elems, len) + } + + def flatten[A](its: ArrayIterator[Iterator[A]]): ArrayIterator[A] = { + var arrayIts = its.map(fromIterator) + var totalLen = 0 + arrayIts.foreach(totalLen += _.len) + val allElems = new Array[AnyRef](totalLen) + var j = 0 + arrayIts.foreach { it => + Array.copy(it.elems, 0, allElems, j, it.len) + j += it.len + } + new ArrayIterator(allElems, totalLen) + } + } +} |