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Standard library for the Scala Programming Language
/*
* Scala (https://www.scala-lang.org)
*
* Copyright EPFL and Lightbend, Inc.
*
* Licensed under Apache License 2.0
* (http://www.apache.org/licenses/LICENSE-2.0).
*
* See the NOTICE file distributed with this work for
* additional information regarding copyright ownership.
*/
package scala
package collection
package mutable
import scala.collection.Stepper.EfficientSplit
import scala.collection.generic.DefaultSerializable
import scala.collection.mutable.{RedBlackTree => RB}
/**
* A mutable sorted map implemented using a mutable red-black tree as underlying data structure.
*
* @param ordering the implicit ordering used to compare objects of type `A`.
* @tparam K the type of the keys contained in this tree map.
* @tparam V the type of the values associated with the keys.
*
* @define Coll mutable.TreeMap
* @define coll mutable tree map
*/
sealed class TreeMap[K, V] private (tree: RB.Tree[K, V])(implicit val ordering: Ordering[K])
extends AbstractMap[K, V]
with SortedMap[K, V]
with SortedMapOps[K, V, TreeMap, TreeMap[K, V]]
with StrictOptimizedIterableOps[(K, V), Iterable, TreeMap[K, V]]
with StrictOptimizedMapOps[K, V, Map, TreeMap[K, V]]
with StrictOptimizedSortedMapOps[K, V, TreeMap, TreeMap[K, V]]
with SortedMapFactoryDefaults[K, V, TreeMap, Iterable, Map]
with DefaultSerializable {
override def sortedMapFactory = TreeMap
/**
* Creates an empty `TreeMap`.
* @param ord the implicit ordering used to compare objects of type `K`.
* @return an empty `TreeMap`.
*/
def this()(implicit ord: Ordering[K]) = this(RB.Tree.empty)(ord)
def iterator: Iterator[(K, V)] = {
if (isEmpty) Iterator.empty
else RB.iterator(tree)
}
override def keysIterator: Iterator[K] = {
if (isEmpty) Iterator.empty
else RB.keysIterator(tree, None)
}
override def valuesIterator: Iterator[V] = {
if (isEmpty) Iterator.empty
else RB.valuesIterator(tree, None)
}
def keysIteratorFrom(start: K): Iterator[K] = {
if (isEmpty) Iterator.empty
else RB.keysIterator(tree, Some(start))
}
def iteratorFrom(start: K): Iterator[(K, V)] = {
if (isEmpty) Iterator.empty
else RB.iterator(tree, Some(start))
}
override def valuesIteratorFrom(start: K): Iterator[V] = {
if (isEmpty) Iterator.empty
else RB.valuesIterator(tree, Some(start))
}
override def stepper[S <: Stepper[_]](implicit shape: StepperShape[(K, V), S]): S with EfficientSplit =
shape.parUnbox(
scala.collection.convert.impl.AnyBinaryTreeStepper.from[(K, V), RB.Node[K, V]](
size, tree.root, _.left, _.right, x => (x.key, x.value)
)
)
override def keyStepper[S <: Stepper[_]](implicit shape: StepperShape[K, S]): S with EfficientSplit = {
import scala.collection.convert.impl._
type T = RB.Node[K, V]
val s = shape.shape match {
case StepperShape.IntShape => IntBinaryTreeStepper.from[T] (size, tree.root, _.left, _.right, _.key.asInstanceOf[Int])
case StepperShape.LongShape => LongBinaryTreeStepper.from[T] (size, tree.root, _.left, _.right, _.key.asInstanceOf[Long])
case StepperShape.DoubleShape => DoubleBinaryTreeStepper.from[T](size, tree.root, _.left, _.right, _.key.asInstanceOf[Double])
case _ => shape.parUnbox(AnyBinaryTreeStepper.from[K, T](size, tree.root, _.left, _.right, _.key))
}
s.asInstanceOf[S with EfficientSplit]
}
override def valueStepper[S <: Stepper[_]](implicit shape: StepperShape[V, S]): S with EfficientSplit = {
import scala.collection.convert.impl._
type T = RB.Node[K, V]
val s = shape.shape match {
case StepperShape.IntShape => IntBinaryTreeStepper.from[T] (size, tree.root, _.left, _.right, _.value.asInstanceOf[Int])
case StepperShape.LongShape => LongBinaryTreeStepper.from[T] (size, tree.root, _.left, _.right, _.value.asInstanceOf[Long])
case StepperShape.DoubleShape => DoubleBinaryTreeStepper.from[T] (size, tree.root, _.left, _.right, _.value.asInstanceOf[Double])
case _ => shape.parUnbox(AnyBinaryTreeStepper.from[V, T] (size, tree.root, _.left, _.right, _.value))
}
s.asInstanceOf[S with EfficientSplit]
}
def addOne(elem: (K, V)): this.type = { RB.insert(tree, elem._1, elem._2); this }
def subtractOne(elem: K): this.type = { RB.delete(tree, elem); this }
override def clear(): Unit = RB.clear(tree)
def get(key: K): Option[V] = RB.get(tree, key)
/**
* Creates a ranged projection of this map. Any mutations in the ranged projection will update the original map and
* vice versa.
*
* Only entries with keys between this projection's key range will ever appear as elements of this map, independently
* of whether the entries are added through the original map or through this view. That means that if one inserts a
* key-value in a view whose key is outside the view's bounds, calls to `get` or `contains` will _not_ consider the
* newly added entry. Mutations are always reflected in the original map, though.
*
* @param from the lower bound (inclusive) of this projection wrapped in a `Some`, or `None` if there is no lower
* bound.
* @param until the upper bound (exclusive) of this projection wrapped in a `Some`, or `None` if there is no upper
* bound.
*/
def rangeImpl(from: Option[K], until: Option[K]): TreeMap[K, V] = new TreeMapProjection(from, until)
override def foreach[U](f: ((K, V)) => U): Unit = RB.foreach(tree, f)
override def foreachEntry[U](f: (K, V) => U): Unit = RB.foreachEntry(tree, f)
override def size: Int = RB.size(tree)
override def knownSize: Int = size
override def isEmpty: Boolean = RB.isEmpty(tree)
override def contains(key: K): Boolean = RB.contains(tree, key)
override def head: (K, V) = RB.min(tree).get
override def last: (K, V) = RB.max(tree).get
override def minAfter(key: K): Option[(K, V)] = RB.minAfter(tree, key)
override def maxBefore(key: K): Option[(K, V)] = RB.maxBefore(tree, key)
override protected[this] def className: String = "TreeMap"
/**
* A ranged projection of a [[TreeMap]]. Mutations on this map affect the original map and vice versa.
*
* Only entries with keys between this projection's key range will ever appear as elements of this map, independently
* of whether the entries are added through the original map or through this view. That means that if one inserts a
* key-value in a view whose key is outside the view's bounds, calls to `get` or `contains` will _not_ consider the
* newly added entry. Mutations are always reflected in the original map, though.
*
* @param from the lower bound (inclusive) of this projection wrapped in a `Some`, or `None` if there is no lower
* bound.
* @param until the upper bound (exclusive) of this projection wrapped in a `Some`, or `None` if there is no upper
* bound.
*/
private[this] final class TreeMapProjection(from: Option[K], until: Option[K]) extends TreeMap[K, V](tree) {
/**
* Given a possible new lower bound, chooses and returns the most constraining one (the maximum).
*/
private[this] def pickLowerBound(newFrom: Option[K]): Option[K] = (from, newFrom) match {
case (Some(fr), Some(newFr)) => Some(ordering.max(fr, newFr))
case (None, _) => newFrom
case _ => from
}
/**
* Given a possible new upper bound, chooses and returns the most constraining one (the minimum).
*/
private[this] def pickUpperBound(newUntil: Option[K]): Option[K] = (until, newUntil) match {
case (Some(unt), Some(newUnt)) => Some(ordering.min(unt, newUnt))
case (None, _) => newUntil
case _ => until
}
/**
* Returns true if the argument is inside the view bounds (between `from` and `until`).
*/
private[this] def isInsideViewBounds(key: K): Boolean = {
val afterFrom = from.isEmpty || ordering.compare(from.get, key) <= 0
val beforeUntil = until.isEmpty || ordering.compare(key, until.get) < 0
afterFrom && beforeUntil
}
override def rangeImpl(from: Option[K], until: Option[K]): TreeMap[K, V] =
new TreeMapProjection(pickLowerBound(from), pickUpperBound(until))
override def get(key: K) = if (isInsideViewBounds(key)) RB.get(tree, key) else None
override def iterator = if (RB.size(tree) == 0) Iterator.empty else RB.iterator(tree, from, until)
override def keysIterator: Iterator[K] = if (RB.size(tree) == 0) Iterator.empty else RB.keysIterator(tree, from, until)
override def valuesIterator: Iterator[V] = if (RB.size(tree) == 0) Iterator.empty else RB.valuesIterator(tree, from, until)
override def keysIteratorFrom(start: K) = if (RB.size(tree) == 0) Iterator.empty else RB.keysIterator(tree, pickLowerBound(Some(start)), until)
override def iteratorFrom(start: K) = if (RB.size(tree) == 0) Iterator.empty else RB.iterator(tree, pickLowerBound(Some(start)), until)
override def valuesIteratorFrom(start: K) = if (RB.size(tree) == 0) Iterator.empty else RB.valuesIterator(tree, pickLowerBound(Some(start)), until)
override def size = if (RB.size(tree) == 0) 0 else iterator.length
override def knownSize: Int = if (RB.size(tree) == 0) 0 else -1
override def isEmpty = RB.size(tree) == 0 || !iterator.hasNext
override def contains(key: K) = isInsideViewBounds(key) && RB.contains(tree, key)
override def head = headOption.get
override def headOption = {
val entry = if (from.isDefined) RB.minAfter(tree, from.get) else RB.min(tree)
(entry, until) match {
case (Some(e), Some(unt)) if ordering.compare(e._1, unt) >= 0 => None
case _ => entry
}
}
override def last = lastOption.get
override def lastOption = {
val entry = if (until.isDefined) RB.maxBefore(tree, until.get) else RB.max(tree)
(entry, from) match {
case (Some(e), Some(fr)) if ordering.compare(e._1, fr) < 0 => None
case _ => entry
}
}
// Using the iterator should be efficient enough; if performance is deemed a problem later, specialized
// `foreach(f, from, until)` and `transform(f, from, until)` methods can be created in `RedBlackTree`. See
// https://github.com/scala/scala/pull/4608#discussion_r34307985 for a discussion about this.
override def foreach[U](f: ((K, V)) => U): Unit = iterator.foreach(f)
override def clone() = super.clone().rangeImpl(from, until)
}
}
/**
* $factoryInfo
*
* @define Coll mutable.TreeMap
* @define coll mutable tree map
*/
@SerialVersionUID(3L)
object TreeMap extends SortedMapFactory[TreeMap] {
def from[K : Ordering, V](it: IterableOnce[(K, V)]): TreeMap[K, V] =
Growable.from(empty[K, V], it)
def empty[K : Ordering, V]: TreeMap[K, V] = new TreeMap[K, V]()
def newBuilder[K: Ordering, V]: Builder[(K, V), TreeMap[K, V]] = new GrowableBuilder(empty[K, V])
}