diff options
author | Martin Odersky <odersky@gmail.com> | 2015-10-04 10:33:54 +0200 |
---|---|---|
committer | Martin Odersky <odersky@gmail.com> | 2015-10-06 13:54:36 +0200 |
commit | 135b7255b3e90117cca9d046a89ef779adbef783 (patch) | |
tree | 7b678a9a30aa9ef682fb4c301e0f3cad7991115a /src/dotty/collections/CollectionStrawMan1.scala | |
parent | 868ae2acb4ef66fa6c32b45e10ba9940ba7340ad (diff) | |
download | dotty-135b7255b3e90117cca9d046a89ef779adbef783.tar.gz dotty-135b7255b3e90117cca9d046a89ef779adbef783.tar.bz2 dotty-135b7255b3e90117cca9d046a89ef779adbef783.zip |
Add ArrayBuffer as another Seq class. Make iterators inspectable.
Diffstat (limited to 'src/dotty/collections/CollectionStrawMan1.scala')
-rw-r--r-- | src/dotty/collections/CollectionStrawMan1.scala | 255 |
1 files changed, 154 insertions, 101 deletions
diff --git a/src/dotty/collections/CollectionStrawMan1.scala b/src/dotty/collections/CollectionStrawMan1.scala index 211c8d7da..ea26eb932 100644 --- a/src/dotty/collections/CollectionStrawMan1.scala +++ b/src/dotty/collections/CollectionStrawMan1.scala @@ -36,9 +36,7 @@ object CollectionStrawMan1 { } /** Base trait for generic collections */ - trait Iterable[+IA] extends HasIterator[IA] with FromIterator[Iterable] { - def buildIterator: Iterator[IA] = iterator - } + trait Iterable[+IA] extends HasIterator[IA] with FromIterator[Iterable] /** Base trait for sequence collections */ trait Seq[+AA] extends Iterable[AA] with FromIterator[Seq] { @@ -50,67 +48,67 @@ object CollectionStrawMan1 { /** Operations returning types unrelated to current collection */ trait Ops[A] extends Any { - def toIterator: Iterator[A] - def foreach(f: A => Unit): Unit = toIterator.foreach(f) - def foldLeft[B](z: B)(op: (B, A) => B): B = toIterator.foldLeft(z)(op) - def foldRight[B](z: B)(op: (A, B) => B): B = toIterator.foldRight(z)(op) - def indexWhere(p: A => Boolean): Int = toIterator.indexWhere(p) - def head: A = toIterator.next - def view: View[A] = new View(toIterator) - def collect[C[X] <: Iterable[X]](fi: FromIterator[C]): C[A] = fi.fromIterator(toIterator) + def iterator: Iterator[A] + def foreach(f: A => Unit): Unit = iterator.foreach(f) + def foldLeft[B](z: B)(op: (B, A) => B): B = iterator.foldLeft(z)(op) + def foldRight[B](z: B)(op: (A, B) => B): B = iterator.foldRight(z)(op) + def indexWhere(p: A => Boolean): Int = iterator.indexWhere(p) + def head: A = iterator.next + def view: View[A] = new View(iterator) + def collect[C[X] <: Iterable[X]](fi: FromIterator[C]): C[A] = fi.fromIterator(iterator) } /** Transforms returning same collection type */ trait MonoTransforms[A, Repr] extends Any { - def toIterator: Iterator[A] - def fromIterator(it: => Iterator[A]): Repr + protected def iter: Iterator[A] + protected def fromIter(it: => Iterator[A]): Repr def partition(p: A => Boolean): (Repr, Repr) = { - val (xs, ys) = toIterator.partition(p) - (fromIterator(xs), fromIterator(ys)) + val (xs, ys) = iter.partition(p) + (fromIter(xs), fromIter(ys)) } - def drop(n: Int): Repr = fromIterator(toIterator.drop(n)) + def drop(n: Int): Repr = fromIter(iter.drop(n)) } /** Transforms returning same collection type constructor */ trait PolyTransforms[A, C[X]] extends Any { - def toIterator: Iterator[A] - def fromIterator[B](it: => Iterator[B]): C[B] - def map[B](f: A => B): C[B] = fromIterator(toIterator.map(f)) - def flatMap[B](f: A => CanIterate[B]): C[B] = fromIterator(toIterator.flatMap(f(_))) - def ++[B >: A](xs: CanIterate[B]): C[B] = fromIterator(toIterator ++ xs) - def zip[B](xs: CanIterate[B]): C[(A, B)] = fromIterator(toIterator.zip(xs.iterator)) + protected def iter: Iterator[A] + protected def fromIter[B](it: => Iterator[B]): C[B] + def map[B](f: A => B): C[B] = fromIter(iter.map(f)) + def flatMap[B](f: A => CanIterate[B]): C[B] = fromIter(iter.flatMap(f(_))) + def ++[B >: A](xs: CanIterate[B]): C[B] = fromIter(iter ++ xs) + def zip[B](xs: CanIterate[B]): C[(A, B)] = fromIter(iter.zip(xs.iterator)) } /** Transforms that only apply to Seq */ trait MonoTransformsOfSeqs[A, Repr] extends Any with MonoTransforms[A, Repr] { - def reverse: Repr = fromIterator(toIterator.reverse) + def reverse: Repr = fromIter(iter.reverse) } /** Implementation of Ops for all generic collections */ implicit class IterableOps[A](val c: Iterable[A]) extends AnyVal with Ops[A] { - def toIterator = c.iterator + def iterator = c.iterator } /** Implementation of MonoTransforms for all generic collections */ implicit class IterableMonoTransforms[A, C[X] <: Iterable[X]](val c: Iterable[A] with FromIterator[C]) extends AnyVal with MonoTransforms[A, C[A]] { - def toIterator = c.buildIterator - def fromIterator(it: => Iterator[A]): C[A] = c.fromIterator(it) + protected def iter = c.iterator + protected def fromIter(it: => Iterator[A]): C[A] = c.fromIterator(it) } /** Implementation of PolyTransforms for all generic collections */ implicit class IterablePolyTransforms[A, C[X] <: Iterable[X]](val c: Iterable[A] with FromIterator[C]) extends AnyVal with PolyTransforms[A, C] { - def toIterator = c.buildIterator - def fromIterator[B](it: => Iterator[B]) = c.fromIterator(it) + protected def iter = c.iterator + protected def fromIter[B](it: => Iterator[B]) = c.fromIterator(it) } /** Implementation of MonoTransformsForSeqs for all generic collections */ implicit class SeqMonoTransforms[A, C[X] <: Seq[X]](val c: Seq[A] with FromIterator[C]) extends AnyVal with MonoTransformsOfSeqs[A, C[A]] { - def toIterator = c.buildIterator - def fromIterator(it: => Iterator[A]) = c.fromIterator(it) + protected def iter = c.iterator + protected def fromIter(it: => Iterator[A]) = c.fromIterator(it) } /* --------- Concrete collection types ------------------------------- */ @@ -156,41 +154,80 @@ object CollectionStrawMan1 { def tail = ??? } + /** Concrete collection type: ArrayBuffer */ + class ArrayBuffer[A] private (initElems: Array[AnyRef], initLen: Int = 0) extends Seq[A] with FromIterator[ArrayBuffer] { + def this() = this(new Array[AnyRef](16)) + private var elems: Array[AnyRef] = initElems + private var len = 0 + def apply(i: Int) = elems(i).asInstanceOf[A] + def length = len + def iterator = new RandomAccessIterator[A] { + override val knownLength = len + def apply(n: Int) = elems(n).asInstanceOf[A] + } + def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] = + ArrayBuffer.fromIterator(it) + def +=(elem: A): this.type = { + if (len == elems.length) { + val newelems = new Array[AnyRef](len * 2) + Array.copy(elems, 0, newelems, 0, len) + elems = newelems + } + elems(len) = elem.asInstanceOf[AnyRef] + len += 1 + this + } + override def toString = elems.take(len).deep.toString + } + + object ArrayBuffer extends IterableFactory[ArrayBuffer] { + def fromIterator[B](it: Iterator[B]): ArrayBuffer[B] = + if (it.knownLength == 0) { + val elems = new Array[AnyRef](it.knownLength) + for (i <- 0 until elems.length) elems(i) = it.next.asInstanceOf[AnyRef] + new ArrayBuffer(elems) + } + else { + val buf = new ArrayBuffer[B] + while (it.hasNext) buf += it.next + buf + } + } + /** Concrete collection type: View */ class View[+A](it: => Iterator[A]) extends HasIterator[A] { def iterator = it } implicit class ViewOps[A](val v: View[A]) extends AnyVal with Ops[A] { - def toIterator = v.iterator - def cache = collect(List).view + def iterator = v.iterator + def cache = collect(ArrayBuffer).view } implicit class ViewMonoTransforms[A](val v: View[A]) extends AnyVal with MonoTransforms[A, View[A]] { - def toIterator = v.iterator - def fromIterator(it: => Iterator[A]): View[A] = new View(it) + protected def iter = v.iterator + protected def fromIter(it: => Iterator[A]): View[A] = new View(it) } implicit class ViewPolyTransforms[A](val v: View[A]) extends AnyVal with PolyTransforms[A, View] { - def toIterator = v.iterator - def fromIterator[B](it: => Iterator[B]) = new View(it) + protected def iter = v.iterator + protected def fromIter[B](it: => Iterator[B]) = new View(it) } /** Concrete collection type: String */ implicit class StringOps(val s: String) extends AnyVal with Ops[Char] { def iterator: Iterator[Char] = new RandomAccessIterator[Char] { - def length = s.length + override val knownLength = s.length def apply(n: Int) = s.charAt(n) } - def toIterator = iterator } implicit class StringMonoTransforms(val s: String) extends AnyVal with MonoTransformsOfSeqs[Char, String] { - def toIterator = s.iterator - def fromIterator(it: => Iterator[Char]) = { + protected def iter = StringOps(s).iterator + protected def fromIter(it: => Iterator[Char]) = { val sb = new StringBuilder for (ch <- it) sb.append(ch) sb.toString @@ -199,8 +236,8 @@ object CollectionStrawMan1 { implicit class StringPolyTransforms(val s: String) extends AnyVal with PolyTransforms[Char, Seq] { - def toIterator = s.iterator - def fromIterator[B](it: => Iterator[B]) = List.fromIterator(it) + protected def iter = StringOps(s).iterator + protected def fromIter[B](it: => Iterator[B]) = List.fromIterator(it) def map(f: Char => Char): String = { val sb = new StringBuilder for (ch <- s) sb.append(f(ch)) @@ -240,91 +277,107 @@ object CollectionStrawMan1 { } -1 } - def map[B](f: A => B): Iterator[B] = new Iterator[B] { - def hasNext = self.hasNext - def next = f(self.next) - } - def flatMap[B](f: A => CanIterate[B]): Iterator[B] = new Iterator[B] { - private var myCurrent: Iterator[B] = Iterator.empty - private def current = { - while (!myCurrent.hasNext && self.hasNext) myCurrent = f(self.next).iterator - myCurrent - } - def hasNext = current.hasNext - def next = current.next - } - def ++[B >: A](xs: CanIterate[B]): Iterator[B] = new Iterator[B] { - private var myCurrent: Iterator[B] = self - private def current = { - if (!myCurrent.hasNext && myCurrent.eq(self)) myCurrent = xs.iterator - myCurrent - } - def hasNext = current.hasNext - def next = current.next - } + def map[B](f: A => B): Iterator[B] = Iterator.Map(this, f) + def flatMap[B](f: A => CanIterate[B]): Iterator[B] = Iterator.FlatMap(this, f) + def ++[B >: A](xs: CanIterate[B]): Iterator[B] = Iterator.Concat(this, xs.iterator) def partition(p: A => Boolean): (Iterator[A], Iterator[A]) = { val lookaheadTrue, lookaheadFalse = new ListBuffer[A] - class PartIterator[+A](buf: ListBuffer[A]) extends Iterator[A] { - final def hasNext: Boolean = - buf.nonEmpty || - self.hasNext && { - val elem = self.next - (if (p(elem)) lookaheadTrue else lookaheadFalse) += elem - hasNext - } - final def next = - if (hasNext) { - val r = buf.head - buf.trimStart(1) - r - } - else Iterator.nextOnEmpty - } - (new PartIterator(lookaheadTrue), new PartIterator(lookaheadFalse)) - } - def drop(n: Int): Iterator[A] = { - if (n <= 0) this - else { - next - drop(n - 1) - } - } - def zip[B](that: CanIterate[B]): Iterator[(A, B)] = new Iterator[(A, B)] { - val ti = that.iterator - def hasNext = self.hasNext && ti.hasNext - def next = (self.next, ti.next) + (Iterator.Partition(this, p, lookaheadTrue, lookaheadFalse), + Iterator.Partition[A](this, !p(_), lookaheadFalse, lookaheadTrue)) } + def drop(n: Int): Iterator[A] = Iterator.Drop(this, n) + def zip[B](that: CanIterate[B]): Iterator[(A, B)] = Iterator.Zip(this, that.iterator) def reverse: Iterator[A] = { var elems: List[A] = Nil while (hasNext) elems = Cons(next, elems) elems.iterator } + def underlying: Iterator[_] = this + def knownLength = -1 } object Iterator { val empty: Iterator[Nothing] = new Iterator[Nothing] { def hasNext = false def next = ??? + override val knownLength = 0 } def apply[A](xs: A*): Iterator[A] = new RandomAccessIterator[A] { - def length = xs.length + override val knownLength = xs.length def apply(n: Int) = xs(n) } def nextOnEmpty = throw new NoSuchElementException("next on empty iterator") + + case class Map[A, B](override val underlying: Iterator[A], f: A => B) extends Iterator[B] { + def hasNext = underlying.hasNext + def next = f(underlying.next) + override val knownLength = underlying.knownLength + } + case class FlatMap[A, B](override val underlying: Iterator[A], f: A => CanIterate[B]) extends Iterator[B] { + private var myCurrent: Iterator[B] = Iterator.empty + private def current = { + while (!myCurrent.hasNext && underlying.hasNext) + myCurrent = f(underlying.next).iterator + myCurrent + } + def hasNext = current.hasNext + def next = current.next + } + case class Concat[A](override val underlying: Iterator[A], other: Iterator[A]) extends Iterator[A] { + private var myCurrent = underlying + private def current = { + if (!myCurrent.hasNext && myCurrent.eq(underlying)) myCurrent = other + myCurrent + } + def hasNext = current.hasNext + def next = current.next + override val knownLength = + if (underlying.knownLength > 0 && other.knownLength > 0) + underlying.knownLength + other.knownLength + else -1 + } + case class Partition[A](override val underlying: Iterator[A], p: A => Boolean, lookahead: ListBuffer[A], dual: ListBuffer[A]) extends Iterator[A] { + final def hasNext: Boolean = + lookahead.nonEmpty || + underlying.hasNext && { + val elem = underlying.next + (if (p(elem)) lookahead else dual) += elem + hasNext + } + final def next = + if (hasNext) { + val r = lookahead.head + lookahead.trimStart(1) + r + } else Iterator.nextOnEmpty + } + case class Drop[A](override val underlying: Iterator[A], n: Int) extends Iterator[A] { + var toSkip = n + def hasNext: Boolean = underlying.hasNext && ( + toSkip == 0 || { underlying.next; toSkip -= 1; hasNext }) + def next = if (hasNext) underlying.next else nextOnEmpty + override val knownLength = (underlying.knownLength - n) max -1 + } + case class Zip[A, B](override val underlying: Iterator[A], other: Iterator[B]) extends Iterator[(A, B)] { + def hasNext = underlying.hasNext && other.hasNext + def next = (underlying.next, other.next) + override val knownLength = underlying.knownLength min other.knownLength + } + class Reverse[A](underlying: RandomAccessIterator[A]) extends RandomAccessIterator[A] { + override val knownLength = underlying.knownLength + def apply(n: Int) = underlying.apply(knownLength - 1 - n) + } } trait RandomAccessIterator[+A] extends Iterator[A] { self => def apply(n: Int): A - def length: Int - protected val len = length + def knownLength: Int + def length: Int = knownLength private var cur = 0 - def hasNext = cur < len + def hasNext = cur < knownLength def next: A = { val r = this(cur); cur += 1; r } override def drop(n: Int): Iterator[A] = { cur += (n max 0); this } - override def reverse = new RandomAccessIterator[A] { - def length = self.length - def apply(n: Int) = apply(len - 1 - n) - } + override def reverse: Iterator[A] = new Iterator.Reverse(this) } } |