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author | Adriaan Moors <adriaan.moors@epfl.ch> | 2012-06-08 06:19:40 -0700 |
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committer | Adriaan Moors <adriaan.moors@epfl.ch> | 2012-06-08 06:19:40 -0700 |
commit | 1fac5bcbbcb9bbfc5953c29574f3952b97945921 (patch) | |
tree | a1f63a911b25a05eaed9e05972702913f17fe533 /src/library | |
parent | 5cd82554069508af769d59f9e41af36f6524b4cc (diff) | |
parent | 0291797fec629c750cefea17ff23c9adc236fec4 (diff) | |
download | scala-1fac5bcbbcb9bbfc5953c29574f3952b97945921.tar.gz scala-1fac5bcbbcb9bbfc5953c29574f3952b97945921.tar.bz2 scala-1fac5bcbbcb9bbfc5953c29574f3952b97945921.zip |
Merge pull request #672 from axel22/issue/5857
Fixes SI-5857. More efficient min and max in Range and NumericRange
Diffstat (limited to 'src/library')
-rw-r--r-- | src/library/scala/collection/immutable/NumericRange.scala | 30 | ||||
-rw-r--r-- | src/library/scala/collection/immutable/Range.scala | 14 |
2 files changed, 42 insertions, 2 deletions
diff --git a/src/library/scala/collection/immutable/NumericRange.scala b/src/library/scala/collection/immutable/NumericRange.scala index 4c82d99c03..5662a11f93 100644 --- a/src/library/scala/collection/immutable/NumericRange.scala +++ b/src/library/scala/collection/immutable/NumericRange.scala @@ -124,7 +124,21 @@ extends AbstractSeq[T] with IndexedSeq[T] with Serializable { if (idx < 0 || idx >= length) throw new IndexOutOfBoundsException(idx.toString) else locationAfterN(idx) } - + + import NumericRange.defaultOrdering + + override def min[T1 >: T](implicit ord: Ordering[T1]): T = + if (ord eq defaultOrdering(num)) { + if (num.signum(step) > 0) start + else last + } else super.min(ord) + + override def max[T1 >: T](implicit ord: Ordering[T1]): T = + if (ord eq defaultOrdering(num)) { + if (num.signum(step) > 0) last + else start + } else super.max(ord) + // Motivated by the desire for Double ranges with BigDecimal precision, // we need some way to map a Range and get another Range. This can't be // done in any fully general way because Ranges are not arbitrary @@ -199,6 +213,7 @@ extends AbstractSeq[T] with IndexedSeq[T] with Serializable { /** A companion object for numeric ranges. */ object NumericRange { + /** Calculates the number of elements in a range given start, end, step, and * whether or not it is inclusive. Throws an exception if step == 0 or * the number of elements exceeds the maximum Int. @@ -257,5 +272,18 @@ object NumericRange { new Exclusive(start, end, step) def inclusive[T](start: T, end: T, step: T)(implicit num: Integral[T]): Inclusive[T] = new Inclusive(start, end, step) + + private[collection] val defaultOrdering = Map[Numeric[_], Ordering[_]]( + Numeric.BigIntIsIntegral -> Ordering.BigInt, + Numeric.IntIsIntegral -> Ordering.Int, + Numeric.ShortIsIntegral -> Ordering.Short, + Numeric.ByteIsIntegral -> Ordering.Byte, + Numeric.CharIsIntegral -> Ordering.Char, + Numeric.LongIsIntegral -> Ordering.Long, + Numeric.FloatAsIfIntegral -> Ordering.Float, + Numeric.DoubleAsIfIntegral -> Ordering.Double, + Numeric.BigDecimalAsIfIntegral -> Ordering.BigDecimal + ) + } diff --git a/src/library/scala/collection/immutable/Range.scala b/src/library/scala/collection/immutable/Range.scala index 033331b58b..7607837491 100644 --- a/src/library/scala/collection/immutable/Range.scala +++ b/src/library/scala/collection/immutable/Range.scala @@ -78,7 +78,19 @@ extends collection.AbstractSeq[Int] final val terminalElement = start + numRangeElements * step override def last = if (isEmpty) Nil.last else lastElement - + + override def min[A1 >: Int](implicit ord: Ordering[A1]): Int = + if (ord eq Ordering.Int) { + if (step > 0) start + else last + } else super.min(ord) + + override def max[A1 >: Int](implicit ord: Ordering[A1]): Int = + if (ord eq Ordering.Int) { + if (step > 0) last + else start + } else super.max(ord) + protected def copy(start: Int, end: Int, step: Int): Range = new Range(start, end, step) /** Create a new range with the `start` and `end` values of this range and |