org.scalacheck.util.FreqMap.scala Maven / Gradle / Ivy
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/*
* ScalaCheck
* Copyright (c) 2007-2021 Rickard Nilsson. All rights reserved.
* http://www.scalacheck.org
*
* This software is released under the terms of the Revised BSD License.
* There is NO WARRANTY. See the file LICENSE for the full text.
*/
package org.scalacheck.util
import org.scalacheck.ScalaVersionSpecific.*
sealed trait FreqMap[T] extends Serializable {
protected val underlying: scala.collection.immutable.Map[T, Int]
def total: Int
def +(t: T): FreqMap[T] = new FreqMap[T] {
private val n = FreqMap.this.underlying.get(t) match {
case None => 1
case Some(n) => n + 1
}
val underlying = FreqMap.this.underlying + (t -> n)
val total = FreqMap.this.total + 1
}
def -(t: T): FreqMap[T] = new FreqMap[T] {
val underlying = FreqMap.this.underlying.get(t) match {
case None => FreqMap.this.underlying
case Some(n) => FreqMap.this.underlying + (t -> (n - 1))
}
val total = FreqMap.this.total + 1
}
def ++(fm: FreqMap[T]): FreqMap[T] = new FreqMap[T] {
private val keys = FreqMap.this.underlying.keySet ++ fm.underlying.keySet
private val mappings = toLazyList(keys).map { x =>
(x, fm.getCount(x).getOrElse(0) + FreqMap.this.getCount(x).getOrElse(0))
}
val underlying = scala.collection.immutable.Map(mappings*)
val total = FreqMap.this.total + fm.total
}
def --(fm: FreqMap[T]): FreqMap[T] = new FreqMap[T] {
val underlying = FreqMap.this.underlying transform {
case (x, n) => n - fm.getCount(x).getOrElse(0)
}
lazy val total = underlying.valuesIterator.foldLeft(0)(_ + _)
}
def getCount(t: T) = underlying.get(t)
def getCounts: List[(T, Int)] = underlying.toList.sortBy(-_._2)
def getRatio(t: T) = for (c <- getCount(t)) yield c.toFloat / total
def getRatios = for ((t, c) <- getCounts) yield (t, c.toFloat / total)
override def toString = underlying.toString
}
object FreqMap {
def empty[T]: FreqMap[T] = new FreqMap[T] {
val underlying = scala.collection.immutable.Map.empty[T, Int]
val total = 0
}
}