diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/library/scala/collection/immutable/NumericRange.scala | 33 | ||||
| -rw-r--r-- | src/library/scala/collection/immutable/Range.scala | 21 |
2 files changed, 48 insertions, 6 deletions
diff --git a/src/library/scala/collection/immutable/NumericRange.scala b/src/library/scala/collection/immutable/NumericRange.scala index 486c2b6c8f..249d76584d 100644 --- a/src/library/scala/collection/immutable/NumericRange.scala +++ b/src/library/scala/collection/immutable/NumericRange.scala @@ -175,9 +175,36 @@ extends AbstractSeq[T] with IndexedSeq[T] with Serializable { catch { case _: ClassCastException => false } final override def sum[B >: T](implicit num: Numeric[B]): B = { - if (isEmpty) this.num fromInt 0 - else if (numRangeElements == 1) head - else ((this.num fromInt numRangeElements) * (head + last) / (this.num fromInt 2)) + // arithmetic series formula can be used for regular addition + if ((num eq scala.math.Numeric.IntIsIntegral)|| + (num eq scala.math.Numeric.BigIntIsIntegral)|| + (num eq scala.math.Numeric.ShortIsIntegral)|| + (num eq scala.math.Numeric.ByteIsIntegral)|| + (num eq scala.math.Numeric.CharIsIntegral)|| + (num eq scala.math.Numeric.LongIsIntegral)|| + (num eq scala.math.Numeric.FloatAsIfIntegral)|| + (num eq scala.math.Numeric.BigDecimalIsFractional)|| + (num eq scala.math.Numeric.DoubleAsIfIntegral)) { + val numAsIntegral = num.asInstanceOf[Integral[B]] + import numAsIntegral._ + if (isEmpty) num fromInt 0 + else if (numRangeElements == 1) head + else ((num fromInt numRangeElements) * (head + last) / (num fromInt 2)) + } else { + // user provided custom Numeric, we cannot rely on arithmetic series formula + if (isEmpty) num.zero + else { + var acc = num.zero + var i = head + var idx = 0 + while(idx < length) { + acc = num.plus(acc, i) + i = i + step + idx = idx + 1 + } + acc + } + } } override lazy val hashCode = super.hashCode() diff --git a/src/library/scala/collection/immutable/Range.scala b/src/library/scala/collection/immutable/Range.scala index 00f398a4b0..786b18cd21 100644 --- a/src/library/scala/collection/immutable/Range.scala +++ b/src/library/scala/collection/immutable/Range.scala @@ -259,9 +259,24 @@ extends scala.collection.AbstractSeq[Int] final def contains(x: Int) = isWithinBoundaries(x) && ((x - start) % step == 0) final override def sum[B >: Int](implicit num: Numeric[B]): Int = { - if (isEmpty) 0 - else if (numRangeElements == 1) head - else (numRangeElements.toLong * (head + last) / 2).toInt + if (num eq scala.math.Numeric.IntIsIntegral) { + // this is normal integer range with usual addition. arithmetic series formula can be used + if (isEmpty) 0 + else if (numRangeElements == 1) head + else (numRangeElements.toLong * (head + last) / 2).toInt + } else { + // user provided custom Numeric, we cannot rely on arithmetic series formula + if (isEmpty) num.toInt(num.zero) + else { + var acc = num.zero + var i = head + while(i != terminalElement) { + acc = num.plus(acc, i) + i = i + step + } + num.toInt(acc) + } + } } override def toIterable = this |