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Standard library for the Scala Programming Language
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala
package collection
package immutable
import scala.collection.generic.{ CanBuildFrom, BitOperations }
import scala.collection.mutable.{ Builder, MapBuilder }
/** Utility class for long maps.
* @author David MacIver
*/
private[immutable] object LongMapUtils extends BitOperations.Long {
def branchMask(i: Long, j: Long) = highestOneBit(i ^ j)
def join[T](p1: Long, t1: LongMap[T], p2: Long, t2: LongMap[T]): LongMap[T] = {
val m = branchMask(p1, p2)
val p = mask(p1, m)
if (zero(p1, m)) LongMap.Bin(p, m, t1, t2)
else LongMap.Bin(p, m, t2, t1)
}
def bin[T](prefix: Long, mask: Long, left: LongMap[T], right: LongMap[T]): LongMap[T] = (left, right) match {
case (left, LongMap.Nil) => left
case (LongMap.Nil, right) => right
case (left, right) => LongMap.Bin(prefix, mask, left, right)
}
}
import LongMapUtils._
/** A companion object for long maps.
*
* @define Coll `LongMap`
* @define mapCanBuildFromInfo
* The standard `CanBuildFrom` instance for `$Coll` objects.
* The created value is an instance of class `MapCanBuildFrom`.
* @since 2.7
*/
object LongMap {
/** $mapCanBuildFromInfo */
implicit def canBuildFrom[A, B] = new CanBuildFrom[LongMap[A], (Long, B), LongMap[B]] {
def apply(from: LongMap[A]): Builder[(Long, B), LongMap[B]] = apply()
def apply(): Builder[(Long, B), LongMap[B]] = new MapBuilder[Long, B, LongMap[B]](empty[B])
}
def empty[T]: LongMap[T] = LongMap.Nil
def singleton[T](key: Long, value: T): LongMap[T] = LongMap.Tip(key, value)
def apply[T](elems: (Long, T)*): LongMap[T] =
elems.foldLeft(empty[T])((x, y) => x.updated(y._1, y._2))
private[immutable] case object Nil extends LongMap[Nothing] {
// Important, don't remove this! See IntMap for explanation.
override def equals(that : Any) = that match {
case (that: AnyRef) if (this eq that) => true
case (that: LongMap[_]) => false // The only empty LongMaps are eq Nil
case that => super.equals(that)
}
}
private[immutable] case class Tip[+T](key: Long, value: T) extends LongMap[T] {
def withValue[S](s: S) =
if (s.asInstanceOf[AnyRef] eq value.asInstanceOf[AnyRef]) this.asInstanceOf[LongMap.Tip[S]]
else LongMap.Tip(key, s)
}
private[immutable] case class Bin[+T](prefix: Long, mask: Long, left: LongMap[T], right: LongMap[T]) extends LongMap[T] {
def bin[S](left: LongMap[S], right: LongMap[S]): LongMap[S] = {
if ((this.left eq left) && (this.right eq right)) this.asInstanceOf[LongMap.Bin[S]]
else LongMap.Bin[S](prefix, mask, left, right)
}
}
}
import LongMap._
// Iterator over a non-empty LongMap.
private[immutable] abstract class LongMapIterator[V, T](it: LongMap[V]) extends AbstractIterator[T] {
// Basically this uses a simple stack to emulate conversion over the tree. However
// because we know that Longs are only 64 bits we can have at most 64 LongMap.Bins and
// one LongMap.Tip sitting on the tree at any point. Therefore we know the maximum stack
// depth is 65
var index = 0
var buffer = new Array[AnyRef](65)
def pop() = {
index -= 1
buffer(index).asInstanceOf[LongMap[V]]
}
def push(x: LongMap[V]) {
buffer(index) = x.asInstanceOf[AnyRef]
index += 1
}
push(it);
/**
* What value do we assign to a tip?
*/
def valueOf(tip: LongMap.Tip[V]): T
def hasNext = index != 0
final def next: T =
pop() match {
case LongMap.Bin(_,_, [email protected](_, _), right) => {
push(right)
valueOf(t)
}
case LongMap.Bin(_, _, left, right) => {
push(right)
push(left)
next
}
case [email protected](_, _) => valueOf(t)
// This should never happen. We don't allow LongMap.Nil in subtrees of the LongMap
// and don't return an LongMapIterator for LongMap.Nil.
case LongMap.Nil => sys.error("Empty maps not allowed as subtrees")
}
}
private[immutable] class LongMapEntryIterator[V](it: LongMap[V]) extends LongMapIterator[V, (Long, V)](it){
def valueOf(tip: LongMap.Tip[V]) = (tip.key, tip.value)
}
private[immutable] class LongMapValueIterator[V](it: LongMap[V]) extends LongMapIterator[V, V](it){
def valueOf(tip: LongMap.Tip[V]) = tip.value
}
private[immutable] class LongMapKeyIterator[V](it: LongMap[V]) extends LongMapIterator[V, Long](it){
def valueOf(tip: LongMap.Tip[V]) = tip.key
}
/**
* Specialised immutable map structure for long keys, based on
* Fast Mergeable Long Maps
* by Okasaki and Gill. Essentially a trie based on binary digits of the integers.
*
* Note: This class is as of 2.8 largely superseded by HashMap.
*
* @tparam T type of the values associated with the long keys.
*
* @since 2.7
* @define Coll `immutable.LongMap`
* @define coll immutable long integer map
* @define mayNotTerminateInf
* @define willNotTerminateInf
*/
sealed abstract class LongMap[+T]
extends AbstractMap[Long, T]
with Map[Long, T]
with MapLike[Long, T, LongMap[T]] {
override def empty: LongMap[T] = LongMap.Nil
override def toList = {
val buffer = new scala.collection.mutable.ListBuffer[(Long, T)]
foreach(buffer += _)
buffer.toList
}
/**
* Iterator over key, value pairs of the map in unsigned order of the keys.
*
* @return an iterator over pairs of long keys and corresponding values.
*/
def iterator: Iterator[(Long, T)] = this match {
case LongMap.Nil => Iterator.empty
case _ => new LongMapEntryIterator(this)
}
/**
* Loops over the key, value pairs of the map in unsigned order of the keys.
*/
override final def foreach[U](f: ((Long, T)) => U): Unit = this match {
case LongMap.Bin(_, _, left, right) => { left.foreach(f); right.foreach(f) }
case LongMap.Tip(key, value) => f((key, value));
case LongMap.Nil =>
}
override def keysIterator: Iterator[Long] = this match {
case LongMap.Nil => Iterator.empty
case _ => new LongMapKeyIterator(this)
}
/**
* Loop over the keys of the map. The same as keys.foreach(f), but may
* be more efficient.
*
* @param f The loop body
*/
final def foreachKey(f: Long => Unit): Unit = this match {
case LongMap.Bin(_, _, left, right) => { left.foreachKey(f); right.foreachKey(f) }
case LongMap.Tip(key, _) => f(key)
case LongMap.Nil =>
}
override def valuesIterator: Iterator[T] = this match {
case LongMap.Nil => Iterator.empty
case _ => new LongMapValueIterator(this)
}
/**
* Loop over the keys of the map. The same as keys.foreach(f), but may
* be more efficient.
*
* @param f The loop body
*/
final def foreachValue(f: T => Unit): Unit = this match {
case LongMap.Bin(_, _, left, right) => { left.foreachValue(f); right.foreachValue(f) }
case LongMap.Tip(_, value) => f(value)
case LongMap.Nil =>
}
override def stringPrefix = "LongMap"
override def isEmpty = this == LongMap.Nil
override def filter(f: ((Long, T)) => Boolean): LongMap[T] = this match {
case LongMap.Bin(prefix, mask, left, right) => {
val (newleft, newright) = (left.filter(f), right.filter(f))
if ((left eq newleft) && (right eq newright)) this
else bin(prefix, mask, newleft, newright)
}
case LongMap.Tip(key, value) =>
if (f((key, value))) this
else LongMap.Nil
case LongMap.Nil => LongMap.Nil
}
def transform[S](f: (Long, T) => S): LongMap[S] = this match {
case [email protected](prefix, mask, left, right) => b.bin(left.transform(f), right.transform(f))
case [email protected](key, value) => t.withValue(f(key, value))
case LongMap.Nil => LongMap.Nil
}
final override def size: Int = this match {
case LongMap.Nil => 0
case LongMap.Tip(_, _) => 1
case LongMap.Bin(_, _, left, right) => left.size + right.size
}
final def get(key: Long): Option[T] = this match {
case LongMap.Bin(prefix, mask, left, right) => if (zero(key, mask)) left.get(key) else right.get(key)
case LongMap.Tip(key2, value) => if (key == key2) Some(value) else None
case LongMap.Nil => None
}
final override def getOrElse[S >: T](key: Long, default: => S): S = this match {
case LongMap.Nil => default
case LongMap.Tip(key2, value) => if (key == key2) value else default
case LongMap.Bin(prefix, mask, left, right) =>
if (zero(key, mask)) left.getOrElse(key, default) else right.getOrElse(key, default)
}
final override def apply(key: Long): T = this match {
case LongMap.Bin(prefix, mask, left, right) => if (zero(key, mask)) left(key) else right(key)
case LongMap.Tip(key2, value) => if (key == key2) value else sys.error("Key not found")
case LongMap.Nil => sys.error("key not found")
}
def + [S >: T] (kv: (Long, S)): LongMap[S] = updated(kv._1, kv._2)
override def updated[S >: T](key: Long, value: S): LongMap[S] = this match {
case LongMap.Bin(prefix, mask, left, right) =>
if (!hasMatch(key, prefix, mask)) join(key, LongMap.Tip(key, value), prefix, this)
else if (zero(key, mask)) LongMap.Bin(prefix, mask, left.updated(key, value), right)
else LongMap.Bin(prefix, mask, left, right.updated(key, value))
case LongMap.Tip(key2, value2) =>
if (key == key2) LongMap.Tip(key, value)
else join(key, LongMap.Tip(key, value), key2, this)
case LongMap.Nil => LongMap.Tip(key, value)
}
/**
* Updates the map, using the provided function to resolve conflicts if the key is already present.
*
* Equivalent to
* {{{
* this.get(key) match {
* case None => this.update(key, value)
* case Some(oldvalue) => this.update(key, f(oldvalue, value)
* }
* }}}
*
* @tparam S The supertype of values in this `LongMap`.
* @param key The key to update.
* @param value The value to use if there is no conflict.
* @param f The function used to resolve conflicts.
* @return The updated map.
*/
def updateWith[S >: T](key: Long, value: S, f: (T, S) => S): LongMap[S] = this match {
case LongMap.Bin(prefix, mask, left, right) =>
if (!hasMatch(key, prefix, mask)) join(key, LongMap.Tip(key, value), prefix, this)
else if (zero(key, mask)) LongMap.Bin(prefix, mask, left.updateWith(key, value, f), right)
else LongMap.Bin(prefix, mask, left, right.updateWith(key, value, f))
case LongMap.Tip(key2, value2) =>
if (key == key2) LongMap.Tip(key, f(value2, value))
else join(key, LongMap.Tip(key, value), key2, this)
case LongMap.Nil => LongMap.Tip(key, value)
}
def -(key: Long): LongMap[T] = this match {
case LongMap.Bin(prefix, mask, left, right) =>
if (!hasMatch(key, prefix, mask)) this
else if (zero(key, mask)) bin(prefix, mask, left - key, right)
else bin(prefix, mask, left, right - key)
case LongMap.Tip(key2, _) =>
if (key == key2) LongMap.Nil
else this
case LongMap.Nil => LongMap.Nil
}
/**
* A combined transform and filter function. Returns an `LongMap` such that
* for each `(key, value)` mapping in this map, if `f(key, value) == None`
* the map contains no mapping for key, and if `f(key, value)`.
*
* @tparam S The type of the values in the resulting `LongMap`.
* @param f The transforming function.
* @return The modified map.
*/
def modifyOrRemove[S](f: (Long, T) => Option[S]): LongMap[S] = this match {
case LongMap.Bin(prefix, mask, left, right) => {
val newleft = left.modifyOrRemove(f)
val newright = right.modifyOrRemove(f)
if ((left eq newleft) && (right eq newright)) this.asInstanceOf[LongMap[S]]
else bin(prefix, mask, newleft, newright)
}
case LongMap.Tip(key, value) => f(key, value) match {
case None => LongMap.Nil
case Some(value2) =>
//hack to preserve sharing
if (value.asInstanceOf[AnyRef] eq value2.asInstanceOf[AnyRef]) this.asInstanceOf[LongMap[S]]
else LongMap.Tip(key, value2)
}
case LongMap.Nil => LongMap.Nil
}
/**
* Forms a union map with that map, using the combining function to resolve conflicts.
*
* @tparam S The type of values in `that`, a supertype of values in `this`.
* @param that The map to form a union with.
* @param f The function used to resolve conflicts between two mappings.
* @return Union of `this` and `that`, with identical key conflicts resolved using the function `f`.
*/
def unionWith[S >: T](that: LongMap[S], f: (Long, S, S) => S): LongMap[S] = (this, that) match{
case (LongMap.Bin(p1, m1, l1, r1), that@(LongMap.Bin(p2, m2, l2, r2))) =>
if (shorter(m1, m2)) {
if (!hasMatch(p2, p1, m1)) join[S](p1, this, p2, that) // TODO: remove [S] when SI-5548 is fixed
else if (zero(p2, m1)) LongMap.Bin(p1, m1, l1.unionWith(that, f), r1)
else LongMap.Bin(p1, m1, l1, r1.unionWith(that, f))
} else if (shorter(m2, m1)){
if (!hasMatch(p1, p2, m2)) join[S](p1, this, p2, that) // TODO: remove [S] when SI-5548 is fixed
else if (zero(p1, m2)) LongMap.Bin(p2, m2, this.unionWith(l2, f), r2)
else LongMap.Bin(p2, m2, l2, this.unionWith(r2, f))
}
else {
if (p1 == p2) LongMap.Bin(p1, m1, l1.unionWith(l2,f), r1.unionWith(r2, f))
else join[S](p1, this, p2, that) // TODO: remove [S] when SI-5548 is fixed
}
case (LongMap.Tip(key, value), x) => x.updateWith[S](key, value, (x, y) => f(key, y, x)) // TODO: remove [S] when SI-5548 is fixed
case (x, LongMap.Tip(key, value)) => x.updateWith[S](key, value, (x, y) => f(key, x, y))
case (LongMap.Nil, x) => x
case (x, LongMap.Nil) => x
}
/**
* Forms the intersection of these two maps with a combining function. The
* resulting map is a map that has only keys present in both maps and has
* values produced from the original mappings by combining them with `f`.
*
* @tparam S The type of values in `that`.
* @tparam R The type of values in the resulting `LongMap`.
* @param that The map to intersect with.
* @param f The combining function.
* @return Intersection of `this` and `that`, with values for identical keys produced by function `f`.
*/
def intersectionWith[S, R](that: LongMap[S], f: (Long, T, S) => R): LongMap[R] = (this, that) match {
case (LongMap.Bin(p1, m1, l1, r1), [email protected](p2, m2, l2, r2)) =>
if (shorter(m1, m2)) {
if (!hasMatch(p2, p1, m1)) LongMap.Nil
else if (zero(p2, m1)) l1.intersectionWith(that, f)
else r1.intersectionWith(that, f)
} else if (m1 == m2) bin(p1, m1, l1.intersectionWith(l2, f), r1.intersectionWith(r2, f))
else {
if (!hasMatch(p1, p2, m2)) LongMap.Nil
else if (zero(p1, m2)) this.intersectionWith(l2, f)
else this.intersectionWith(r2, f)
}
case (LongMap.Tip(key, value), that) => that.get(key) match {
case None => LongMap.Nil
case Some(value2) => LongMap.Tip(key, f(key, value, value2))
}
case (_, LongMap.Tip(key, value)) => this.get(key) match {
case None => LongMap.Nil
case Some(value2) => LongMap.Tip(key, f(key, value2, value))
}
case (_, _) => LongMap.Nil
}
/**
* Left biased intersection. Returns the map that has all the same mappings as this but only for keys
* which are present in the other map.
*
* @tparam R The type of values in `that`.
* @param that The map to intersect with.
* @return A map with all the keys both in `this` and `that`, mapped to corresponding values from `this`.
*/
def intersection[R](that: LongMap[R]): LongMap[T] =
this.intersectionWith(that, (key: Long, value: T, value2: R) => value)
def ++[S >: T](that: LongMap[S]) =
this.unionWith[S](that, (key, x, y) => y)
}