Makes Range#sum an O(1) operation instead of an O(n) one.

Partially fixes SI-4658. NumericRange stays slow, thanks to the brilliant idea that Numeric doesn't need a division operation.

2 files changed, 121 insertions, 0 deletions

diff --git a/test/files/run/t4658.check b/test/files/run/t4658.check
new file mode 100644
index 0000000000..743b0faee3
--- /dev/null
+++ b/test/files/run/t4658.check
@@ -0,0 +1,80 @@
+Ranges:
+1073741824
+1073741824
+0
+0
+55
+25
+1
+-45
+-55
+0
+-24
+-30
+0
+-40
+-55
+-10
+-24
+-30
+-10
+IntRanges:
+Disabled #1
+Disabled #2
+0
+0
+55
+25
+1
+-45
+-55
+0
+-24
+-30
+0
+-40
+-55
+-10
+-24
+-30
+-10
+LongRanges:
+Disabled #1
+Disabled #2
+0
+0
+55
+25
+1
+-45
+-55
+0
+-24
+-30
+0
+-40
+-55
+-10
+-24
+-30
+-10
+BigIntRanges:
+Disabled #1
+Disabled #2
+0
+0
+55
+25
+1
+-45
+-55
+0
+-24
+-30
+0
+-40
+-55
+-10
+-24
+-30
+-10
diff --git a/test/files/run/t4658.scala b/test/files/run/t4658.scala
new file mode 100644
index 0000000000..e1799fae9b
--- /dev/null
+++ b/test/files/run/t4658.scala
@@ -0,0 +1,41 @@
+import scala.collection.immutable.NumericRange
+//#4658
+object Test {
+
+  case class R(start: Int, end: Int, step: Int = 1, inclusive: Boolean = true)
+
+  val rangeData = Array(
+    R(1, Int.MaxValue), R(-Int.MaxValue, -1), R(0, 0), R(0,0, inclusive = false), R(1,10),
+    R(1,10,2), R(1,10,11), R(-10, -5), R(-10, 0), R(-10, 10), R(-10, -5, 2), R(-10, 0, 2), R(-10, 10, 2),
+    R(-10, -5, inclusive = false), R(-10, 0, inclusive = false), R(-10, 10, inclusive = false),
+    R(-10, -5, 2, inclusive = false), R(-10, 0, 2, inclusive = false), R(-10, 10, 2, inclusive = false)
+  )
+
+  def ranges = rangeData.map(r => if (r.inclusive) r.start to r.end by r.step else r.start until r.end by r.step)
+
+  def numericIntRanges = rangeData.map(r => if (r.inclusive) NumericRange.inclusive(r.start, r.end, r.step) else NumericRange(r.start, r.end, r.step))
+
+  def numericLongRanges = rangeData.map(r => if (r.inclusive) NumericRange.inclusive(r.start.toLong, r.end, r.step) else NumericRange(r.start.toLong, r.end, r.step))
+
+  def numericBigIntRanges = rangeData.map(r => if (r.inclusive) NumericRange.inclusive(BigInt(r.start), BigInt(r.end), BigInt(r.step)) else NumericRange(BigInt(r.start), BigInt(r.end), BigInt(r.step)))
+
+  def main(args: Array[String]) {
+    // We drop the first two tests for all ranges which don't have a decent sum implementation,
+    // because it is just too slow.
+    println("Ranges:")
+    ranges.foreach{range => println(range.sum)}
+    println("IntRanges:")
+    println("Disabled #1")
+    println("Disabled #2")
+    numericIntRanges.drop(2).foreach{range => println(range.sum)}
+    println("LongRanges:")
+    println("Disabled #1")
+    println("Disabled #2")
+    numericLongRanges.drop(2).foreach{range => println(range.sum)}
+    println("BigIntRanges:")
+    println("Disabled #1")
+    println("Disabled #2")
+    numericBigIntRanges.drop(2).foreach{range => println(range.sum)}
+  }
+
+}
\ No newline at end of file