Merge pull request #10627 from GerretS/Add-indexOf-to-NumericRange

Add indexOf() and lastIndexOf() to NumericRange.
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Lukas Rytz 2024-01-19 09:26:33 +01:00 committed by GitHub
commit 1bfec6d501
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2 changed files with 112 additions and 0 deletions

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@ -118,6 +118,38 @@ sealed class NumericRange[T](
} }
} }
private[this] def indexOfTyped(elem: T, from: Int): Int =
posOf(elem) match {
case pos if pos >= from => pos
case _ => -1
}
final override def indexOf[B >: T](elem: B, from: Int): Int =
try indexOfTyped(elem.asInstanceOf[T], from)
catch { case _: ClassCastException => super.indexOf(elem, from) }
private[this] def lastIndexOfTyped(elem: T, end: Int): Int =
posOf(elem) match {
case pos if pos <= end => pos
case _ => -1
}
final override def lastIndexOf[B >: T](elem: B, end: Int = length - 1): Int =
try lastIndexOfTyped(elem.asInstanceOf[T], end)
catch { case _: ClassCastException => super.lastIndexOf(elem, end) }
private[this] def posOf(i: T): Int =
/*
If i is in this NumericRange, its position can simply be calculated by taking the amount of values up till i.
NumericRange.count does this in an most efficient manner.
Note that the contains() method throws an exception if the range has more than Int.MaxValue elements, but so did
the original indexOf / lastIndexOf functions, so no functionality changed. */
if (contains(i)) {
/* Because of zero indexing, the count is always one higher than the index. This can be simply solved by setting
isInclusive = false. */
NumericRange.count(this.start, i, this.step, isInclusive = false)
} else -1
// TODO: these private methods are straight copies from Range, duplicated // TODO: these private methods are straight copies from Range, duplicated
// to guard against any (most likely illusory) performance drop. They should // to guard against any (most likely illusory) performance drop. They should
// be eliminated one way or another. // be eliminated one way or another.

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@ -327,6 +327,86 @@ class NumericRangeTest {
assertTrue(dropped.end == range.end && dropped.step == range.step && dropped.start == (amount * step) + range.start) assertTrue(dropped.end == range.end && dropped.step == range.step && dropped.start == (amount * step) + range.start)
} }
@Test
def indexOfAndLastIndexOfShouldBeCorrect(): Unit = {
// For a range, because every value exists at most once, without the optional from/end param,
// indexOf and lastIndexOf should be equal.
// General checks.
assertEquals(0, NumericRange(0, 1, 1).indexOf(0))
assertEquals(0, NumericRange(0, 1, 1).lastIndexOf(0))
assertEquals(0, NumericRange.inclusive(0, 0, 1).indexOf(0))
assertEquals(0, NumericRange.inclusive(0, 0, 1).lastIndexOf(0))
assertEquals(300, NumericRange(0, Int.MaxValue, 1).indexOf(300))
assertEquals(300, NumericRange(0, Int.MaxValue, 1).lastIndexOf(300))
assertEquals(Int.MaxValue - 1, NumericRange(0, Int.MaxValue, 1).indexOf(Int.MaxValue - 1))
assertEquals(Int.MaxValue - 1, NumericRange(0, Int.MaxValue, 1).lastIndexOf(Int.MaxValue - 1))
assertEquals(300 / 5, NumericRange(0, Int.MaxValue, 5).indexOf(300))
assertEquals(300 / 5, NumericRange(0, Int.MaxValue, 5).lastIndexOf(300))
assertEquals(700, NumericRange(-1000, 0, 1).indexOf(-300))
assertEquals(700, NumericRange(-1000, 0, 1).lastIndexOf(-300))
assertEquals(350, NumericRange(-1000, 0, 2).indexOf(-300))
assertEquals(350, NumericRange(-1000, 0, 2).lastIndexOf(-300))
// If a value is below or over the limits of the range, or fall between steps, should be -1
assertEquals(-1, NumericRange(0, 10, 1).indexOf(20))
assertEquals(-1, NumericRange(0, 10, 1).lastIndexOf(20))
assertEquals(-1, NumericRange(0, 10, 2).indexOf(20))
assertEquals(-1, NumericRange(0, 10, 2).lastIndexOf(20))
assertEquals(-1, NumericRange(0, 10, 1).indexOf(-5))
assertEquals(-1, NumericRange(0, 10, 1).lastIndexOf(-5))
assertEquals(-1, NumericRange(0, 10, 2).indexOf(1))
assertEquals(-1, NumericRange(0, 10, 2).lastIndexOf(1))
assertEquals(-1, NumericRange(0, 10, 2).indexOf(3))
assertEquals(-1, NumericRange(0, 10, 2).lastIndexOf(3))
// indexOf should return -1 if the index is less than the from value
assertEquals(300, NumericRange(0, Int.MaxValue, 1).indexOf(300, 100))
assertEquals(-1, NumericRange(0, Int.MaxValue, 1).indexOf(300, 400))
assertEquals(300, NumericRange(0, Int.MaxValue, 1).indexOf(300, 300))
assertEquals(150, NumericRange(0, Int.MaxValue, 2).indexOf(300, 140))
assertEquals(-1, NumericRange(0, Int.MaxValue, 2).indexOf(300, 160))
// lastIndexOf should return -1 if the index is more than the end value
assertEquals(-1, NumericRange(0, Int.MaxValue, 1).lastIndexOf(300, 100))
assertEquals(300, NumericRange(0, Int.MaxValue, 1).lastIndexOf(300, 400))
assertEquals(300, NumericRange(0, Int.MaxValue, 1).lastIndexOf(300, 300))
assertEquals(-1, NumericRange(0, Int.MaxValue, 2).lastIndexOf(300, 140))
assertEquals(150, NumericRange(0, Int.MaxValue, 2).lastIndexOf(300, 160))
// Sanity check - does it work with other types.
assertEquals(300 / 5, NumericRange(0L, Int.MaxValue.toLong, 5L).indexOf(300L))
assertEquals(300 / 5, NumericRange(0L, Int.MaxValue.toLong, 5L).lastIndexOf(300L))
assertEquals(300 / 5, NumericRange(BigInt(0), BigInt(Int.MaxValue), BigInt(5)).indexOf(BigInt(300)))
assertEquals(300 / 5, NumericRange(BigInt(0), BigInt(Int.MaxValue), BigInt(5)).lastIndexOf(BigInt(300)))
// indexOf different type returns -1
assertEquals(-1, NumericRange(0L, Int.MaxValue.toLong, 5L).indexOf(300))
assertEquals(-1, NumericRange(0L, Int.MaxValue.toLong, 5L).lastIndexOf(300))
/* Attempting an indexOf of a Range with more than Int.MaxValue elements always throws an error.
Not ideal, but this tests whether backwards compatibility is conserved. */
assertThrows[IllegalArgumentException](NumericRange(0L, Int.MaxValue.toLong + 1, 1L).indexOf(300L))
assertThrows[IllegalArgumentException](NumericRange(0L, Int.MaxValue.toLong + 1, 1L).lastIndexOf(300L))
assertThrows[IllegalArgumentException](NumericRange(Int.MinValue, Int.MaxValue, 1).indexOf(300))
assertThrows[IllegalArgumentException](NumericRange(Int.MinValue, Int.MaxValue, 1).lastIndexOf(300))
}
} }
object NumericRangeTest { object NumericRangeTest {