dgd-contributor commented on a change in pull request #33459:
URL: https://github.com/apache/spark/pull/33459#discussion_r677354506
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File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/NumberConverter.scala
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@@ -49,12 +49,14 @@ object NumberConverter {
*/
private def encode(radix: Int, fromPos: Int, value: Array[Byte]): Long = {
var v: Long = 0L
- val bound = java.lang.Long.divideUnsigned(-1 - radix, radix) // Possible
overflow once
+ // bound will always positive since radix >= 2
+ val bound = java.lang.Long.divideUnsigned(-1 - radix, radix)
var i = fromPos
while (i < value.length && value(i) >= 0) {
- if (v >= bound) {
Review comment:
1. Because `v*radix >= v*2` (as `radix >= 2`), so if v is negative,
which mean its bit presentation is start with 1, so if we multiply it by 2, it
will cause overflow.
2. `v >= bound` is sufficient to `v*radix + radix` will cause overflow. But
we need to check that `v*radix + value(i)` is overflow or not and `v*radix +
value(i) <= v*radix + radix`
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