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Add IndexedSeqView to lib
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+191
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‎tests/pos-special/stdlib/collection/IndexedSeq.scala

Lines changed: 4 additions & 2 deletions
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@@ -18,6 +18,8 @@ import scala.collection.Searching.{Found, InsertionPoint, SearchResult}
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import scala.collection.Stepper.EfficientSplit
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import scala.math.Ordering
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import language.experimental.captureChecking
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import caps.unsafe.unsafeAssumePure
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/** Base trait for indexed sequences that have efficient `apply` and `length` */
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trait IndexedSeq[+A] extends Seq[A]
@@ -33,7 +35,7 @@ trait IndexedSeq[+A] extends Seq[A]
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object IndexedSeq extends SeqFactory.Delegate[IndexedSeq](immutable.IndexedSeq)
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/** Base trait for indexed Seq operations */
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trait IndexedSeqOps[+A, +CC[_], +C] extends Any with SeqOps[A, CC, C] { self =>
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trait IndexedSeqOps[+A, +CC[_], +C] extends Any with IndexedSeqViewOps[A, CC, C] with SeqOps[A, CC, C] { self =>
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def iterator: Iterator[A] = view.iterator
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@@ -86,7 +88,7 @@ trait IndexedSeqOps[+A, +CC[_], +C] extends Any with SeqOps[A, CC, C] { self =>
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override def dropRight(n: Int): C = fromSpecific(new IndexedSeqView.DropRight(this, n))
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override def map[B](f: A => B): CC[B] = iterableFactory.from(new IndexedSeqView.Map(this, f))
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override def map[B](f: A => B): CC[B] = iterableFactory.from(new IndexedSeqView.Map(this, f)).unsafeAssumePure
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override def reverse: C = fromSpecific(new IndexedSeqView.Reverse(this))
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‎tests/pos-special/stdlib/collection/IndexedSeqView.scala

Lines changed: 187 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,187 @@
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/*
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* Scala (https://www.scala-lang.org)
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*
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* Copyright EPFL and Lightbend, Inc.
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*
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* Licensed under Apache License 2.0
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* (http://www.apache.org/licenses/LICENSE-2.0).
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*
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* See the NOTICE file distributed with this work for
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* additional information regarding copyright ownership.
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*/
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package scala
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package collection
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import scala.annotation.nowarn
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import language.experimental.captureChecking
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trait IndexedSeqViewOps[+A, +CC[_], +C] extends Any with SeqViewOps[A, CC, C] {
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self: IndexedSeqViewOps[A, CC, C]^ =>
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}
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/** View defined in terms of indexing a range */
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trait IndexedSeqView[+A] extends IndexedSeqViewOps[A, View, View[A]] with SeqView[A] {
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self: IndexedSeqView[A]^ =>
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override def view: IndexedSeqView[A]^{this} = this
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@deprecated("Use .view.slice(from, until) instead of .view(from, until)", "2.13.0")
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override def view(from: Int, until: Int): IndexedSeqView[A]^{this} = view.slice(from, until)
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override def iterator: Iterator[A]^{this} = new IndexedSeqView.IndexedSeqViewIterator(this)
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override def reverseIterator: Iterator[A]^{this} = new IndexedSeqView.IndexedSeqViewReverseIterator(this)
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override def appended[B >: A](elem: B): IndexedSeqView[B]^{this} = new IndexedSeqView.Appended(this, elem)
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override def prepended[B >: A](elem: B): IndexedSeqView[B]^{this} = new IndexedSeqView.Prepended(elem, this)
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override def take(n: Int): IndexedSeqView[A]^{this} = new IndexedSeqView.Take(this, n)
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override def takeRight(n: Int): IndexedSeqView[A]^{this} = new IndexedSeqView.TakeRight(this, n)
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override def drop(n: Int): IndexedSeqView[A]^{this} = new IndexedSeqView.Drop(this, n)
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override def dropRight(n: Int): IndexedSeqView[A]^{this} = new IndexedSeqView.DropRight(this, n)
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override def map[B](f: A => B): IndexedSeqView[B]^{this, f} = new IndexedSeqView.Map(this, f)
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override def reverse: IndexedSeqView[A]^{this} = new IndexedSeqView.Reverse(this)
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override def slice(from: Int, until: Int): IndexedSeqView[A]^{this} = new IndexedSeqView.Slice(this, from, until)
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override def tapEach[U](f: A => U): IndexedSeqView[A]^{this, f} = new IndexedSeqView.Map(this, { (a: A) => f(a); a})
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def concat[B >: A](suffix: IndexedSeqView.SomeIndexedSeqViewOps[B]): IndexedSeqView[B]^{this} = new IndexedSeqView.Concat(this, suffix)
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def appendedAll[B >: A](suffix: IndexedSeqView.SomeIndexedSeqViewOps[B]): IndexedSeqView[B]^{this} = new IndexedSeqView.Concat(this, suffix)
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def prependedAll[B >: A](prefix: IndexedSeqView.SomeIndexedSeqViewOps[B]): IndexedSeqView[B]^{this} = new IndexedSeqView.Concat(prefix, this)
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@nowarn("""cat=deprecation&origin=scala\.collection\.Iterable\.stringPrefix""")
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override protected[this] def stringPrefix: String = "IndexedSeqView"
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}
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object IndexedSeqView {
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@SerialVersionUID(3L)
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private[collection] class IndexedSeqViewIterator[A](self: IndexedSeqView[A]^) extends AbstractIterator[A] with Serializable {
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this: IndexedSeqViewIterator[A]^ =>
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private[this] var current = 0
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private[this] var remainder = self.length
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override def knownSize: Int = remainder
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@inline private[this] def _hasNext: Boolean = remainder > 0
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def hasNext: Boolean = _hasNext
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def next(): A =
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if (_hasNext) {
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val r = self(current)
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current += 1
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remainder -= 1
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r
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} else Iterator.empty.next()
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override def drop(n: Int): Iterator[A]^{this} = {
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if (n > 0) {
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current += n
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remainder = Math.max(0, remainder - n)
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}
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this
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}
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override protected def sliceIterator(from: Int, until: Int): Iterator[A]^{this} = {
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def formatRange(value : Int) : Int = if (value < 0) 0 else if (value > remainder) remainder else value
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val formatFrom = formatRange(from)
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val formatUntil = formatRange(until)
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remainder = Math.max(0, formatUntil - formatFrom)
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current = current + formatFrom
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this
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}
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}
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@SerialVersionUID(3L)
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private[collection] class IndexedSeqViewReverseIterator[A](self: IndexedSeqView[A]^) extends AbstractIterator[A] with Serializable {
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this: IndexedSeqViewReverseIterator[A]^ =>
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private[this] var remainder = self.length
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private[this] var pos = remainder - 1
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@inline private[this] def _hasNext: Boolean = remainder > 0
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def hasNext: Boolean = _hasNext
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def next(): A =
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if (_hasNext) {
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val r = self(pos)
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pos -= 1
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remainder -= 1
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r
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} else Iterator.empty.next()
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// from < 0 means don't move pos, until < 0 means don't limit remainder
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//
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override protected def sliceIterator(from: Int, until: Int): Iterator[A]^{this} = {
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if (_hasNext) {
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if (remainder <= from) remainder = 0 // exhausted by big skip
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else if (from <= 0) { // no skip, pos is same
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if (until >= 0 && until < remainder) remainder = until // ...limited by until
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}
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else {
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pos -= from // skip ahead
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if (until >= 0 && until < remainder) { // ...limited by until
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if (until <= from) remainder = 0 // ...exhausted if limit is smaller than skip
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else remainder = until - from // ...limited by until, less the skip
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}
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else remainder -= from // ...otherwise just less the skip
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}
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}
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this
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}
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}
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/** An `IndexedSeqViewOps` whose collection type and collection type constructor are unknown */
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type SomeIndexedSeqViewOps[A] = IndexedSeqViewOps[A, AnyConstr, _]
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@SerialVersionUID(3L)
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class Id[+A](underlying: SomeIndexedSeqViewOps[A]^)
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extends SeqView.Id(underlying) with IndexedSeqView[A]
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@SerialVersionUID(3L)
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class Appended[+A](underlying: SomeIndexedSeqViewOps[A]^, elem: A)
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extends SeqView.Appended(underlying, elem) with IndexedSeqView[A]
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@SerialVersionUID(3L)
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class Prepended[+A](elem: A, underlying: SomeIndexedSeqViewOps[A]^)
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extends SeqView.Prepended(elem, underlying) with IndexedSeqView[A]
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@SerialVersionUID(3L)
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class Concat[A](prefix: SomeIndexedSeqViewOps[A]^, suffix: SomeIndexedSeqViewOps[A]^)
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extends SeqView.Concat[A](prefix, suffix) with IndexedSeqView[A]
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@SerialVersionUID(3L)
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class Take[A](underlying: SomeIndexedSeqViewOps[A]^, n: Int)
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extends SeqView.Take(underlying, n) with IndexedSeqView[A]
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@SerialVersionUID(3L)
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class TakeRight[A](underlying: SomeIndexedSeqViewOps[A]^, n: Int)
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extends SeqView.TakeRight(underlying, n) with IndexedSeqView[A]
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@SerialVersionUID(3L)
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class Drop[A](underlying: SomeIndexedSeqViewOps[A]^, n: Int)
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extends SeqView.Drop[A](underlying, n) with IndexedSeqView[A]
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@SerialVersionUID(3L)
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class DropRight[A](underlying: SomeIndexedSeqViewOps[A]^, n: Int)
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extends SeqView.DropRight[A](underlying, n) with IndexedSeqView[A]
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@SerialVersionUID(3L)
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class Map[A, B](underlying: SomeIndexedSeqViewOps[A]^, f: A => B)
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extends SeqView.Map(underlying, f) with IndexedSeqView[B]
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@SerialVersionUID(3L)
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class Reverse[A](underlying: SomeIndexedSeqViewOps[A]^) extends SeqView.Reverse[A](underlying) with IndexedSeqView[A] {
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override def reverse: IndexedSeqView[A] = underlying match {
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case x: IndexedSeqView[A] => x
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case _ => super.reverse
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}
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}
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@SerialVersionUID(3L)
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class Slice[A](underlying: SomeIndexedSeqViewOps[A]^, from: Int, until: Int) extends AbstractIndexedSeqView[A] {
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protected val lo = from max 0
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protected val hi = (until max 0) min underlying.length
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protected val len = (hi - lo) max 0
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@throws[IndexOutOfBoundsException]
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def apply(i: Int): A = underlying(lo + i)
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def length: Int = len
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}
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}
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/** Explicit instantiation of the `IndexedSeqView` trait to reduce class file size in subclasses. */
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@SerialVersionUID(3L)
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abstract class AbstractIndexedSeqView[+A] extends AbstractSeqView[A] with IndexedSeqView[A]

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