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author | Rui Gonçalves <ruippeixotog@gmail.com> | 2015-12-06 19:25:00 +0000 |
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committer | Rui Gonçalves <ruippeixotog@gmail.com> | 2015-12-06 19:25:00 +0000 |
commit | c17b18e173e07f421f9171272d94d84908526609 (patch) | |
tree | 3008e9e5be2acc44a6ffc7e56e84fe91fbcb0cb8 /test | |
parent | 5e99f82159842c5e2b60a1427e129b0b720a0d38 (diff) | |
download | scala-c17b18e173e07f421f9171272d94d84908526609.tar.gz scala-c17b18e173e07f421f9171272d94d84908526609.tar.bz2 scala-c17b18e173e07f421f9171272d94d84908526609.zip |
SI-9581 Fix overflow on Vector take and drop methods
Fixes the index/length comparison in `Vector#take` and `Vector#drop` so that they handle all possible integer values.
Given the collection's invariants `startIndex >= endIndex` and `0 >= startIndex, endIndex`, it is sufficient to change the arithmetic in the comparison as done in this commit to avoid overflows. As cases when `n <= 0` are handled beforehand, `endIndex - n` cannot overflow, contrary to `startIndex + n`. If without the danger of overflows the condition yields true, on the other hand, `startIndex + n` cannot overflow as it is smaller than `endIndex` (as the previous formulation of the condition shows).
Diffstat (limited to 'test')
-rw-r--r-- | test/junit/scala/collection/immutable/VectorTest.scala | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/test/junit/scala/collection/immutable/VectorTest.scala b/test/junit/scala/collection/immutable/VectorTest.scala new file mode 100644 index 0000000000..69f74872d0 --- /dev/null +++ b/test/junit/scala/collection/immutable/VectorTest.scala @@ -0,0 +1,30 @@ +package scala.collection.immutable + +import org.junit.Assert._ +import org.junit.runner.RunWith +import org.junit.runners.JUnit4 +import org.junit.Test + +@RunWith(classOf[JUnit4]) +class VectorTest { + + @Test + def hasCorrectDropAndTakeMethods() { + val v = Vector(0) ++ Vector(1 to 64: _*) + + assertEquals(Vector(0, 1), v take 2) + assertEquals(Vector(63, 64), v takeRight 2) + assertEquals(Vector(2 to 64: _*), v drop 2) + assertEquals(Vector(0 to 62: _*), v dropRight 2) + + assertEquals(v, v take Int.MaxValue) + assertEquals(v, v takeRight Int.MaxValue) + assertEquals(Vector.empty[Int], v drop Int.MaxValue) + assertEquals(Vector.empty[Int], v dropRight Int.MaxValue) + + assertEquals(Vector.empty[Int], v take Int.MinValue) + assertEquals(Vector.empty[Int], v takeRight Int.MinValue) + assertEquals(v, v drop Int.MinValue) + assertEquals(v, v dropRight Int.MinValue) + } +} |