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/*-------------------------------------------------------------------------*\
** ScalaCheck **
** Copyright (c) 2007-2014 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
trait FreqMap[T] {
protected val underlying: scala.collection.immutable.Map[T,Int]
val total: Int
def +(t: 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) = 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]) = new FreqMap[T] {
private val keys = FreqMap.this.underlying.keySet ++ fm.underlying.keySet
private val mappings = keys.toStream.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]) = new FreqMap[T] {
val underlying = FreqMap.this.underlying transform {
case (x,n) => n - fm.getCount(x).getOrElse(0)
}
lazy val total = (0 /: underlying.valuesIterator) (_ + _)
}
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: Float)/total
def getRatios = for((t,c) <- getCounts) yield (t, (c: Float)/total)
override def toString = underlying.toString
}
object FreqMap {
def empty[T] = new FreqMap[T] {
val underlying = scala.collection.immutable.Map.empty[T,Int]
val total = 0
}
}
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