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author | Paul Phillips <paulp@improving.org> | 2013-03-26 23:50:50 -0700 |
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committer | Paul Phillips <paulp@improving.org> | 2013-03-26 23:51:25 -0700 |
commit | e3ddb2d7dff859c9fb81d34d1c9687f72321a713 (patch) | |
tree | 1d520b035e5306214fe39ef5333ab7b55caa7867 /test/files/run | |
parent | 59d4998cf4a19eb5d44118d4867c2370e9a935e5 (diff) | |
download | scala-e3ddb2d7dff859c9fb81d34d1c9687f72321a713.tar.gz scala-e3ddb2d7dff859c9fb81d34d1c9687f72321a713.tar.bz2 scala-e3ddb2d7dff859c9fb81d34d1c9687f72321a713.zip |
Iterator.++ no longer blows the stack.
To my chagrin we still hadn't gotten this one. I took a new
approach which seems like a winner to me. Here's a benchmark:
object Test {
def run(n: Int) = println((1 to n).foldLeft(Iterator.empty: Iterator[Int])((res, _) => res ++ Iterator(1)) sum)
def main(args: Array[String]): Unit = run(args(0).toInt)
}
Runtime before this commit for various n:
500 0.403 real
1000 0.911 real
1500 2.351 real
2000 5.298 real
2500 10.184 real
Runtime after this commit, same n:
500 0.346 real
1000 0.359 real
1500 0.368 real
2000 0.379 real
2500 0.390 real
In the test case I dial it up to 100000.
Diffstat (limited to 'test/files/run')
-rw-r--r-- | test/files/run/iterator-concat.check | 4 | ||||
-rw-r--r-- | test/files/run/iterator-concat.scala | 15 |
2 files changed, 19 insertions, 0 deletions
diff --git a/test/files/run/iterator-concat.check b/test/files/run/iterator-concat.check new file mode 100644 index 0000000000..23835b07ae --- /dev/null +++ b/test/files/run/iterator-concat.check @@ -0,0 +1,4 @@ +100 +1000 +10000 +100000 diff --git a/test/files/run/iterator-concat.scala b/test/files/run/iterator-concat.scala new file mode 100644 index 0000000000..f11363410f --- /dev/null +++ b/test/files/run/iterator-concat.scala @@ -0,0 +1,15 @@ +object Test { + // Create `size` Function0s, each of which evaluates to an Iterator + // which produces 1. Then fold them over ++ to get a single iterator, + // which should sum to "size". + def mk(size: Int): Iterator[Int] = { + val closures = (1 to size).toList.map(x => (() => Iterator(1))) + closures.foldLeft(Iterator.empty: Iterator[Int])((res, f) => res ++ f()) + } + def main(args: Array[String]): Unit = { + println(mk(100).sum) + println(mk(1000).sum) + println(mk(10000).sum) + println(mk(100000).sum) + } +} |