Hi,
I tried to reach the author for several weeks but he doesn't seem to respond so
I am trying to reach a wider audience to either confirm my suspicion or to be
corrected. In
http://smalltalkhub.com/#!/~MongoTalkTeam/mongotalk/diff/Mongo-BSON-HenrikSperreJohansen.43
the following change is done:
+ "digitAdd: wraps around to 0 when result would overflow"
+ ^ counter := counter
+ ifNil:[self newCounter]
+ ifNotNil:[counter digitAdd: 1]!
- ^ counter := (counter + 1) \\ 16rFFFFFF!
The old code has overflow checking, the new code makes a statement I don't
think is true. counter is LargePositiveInteger new: 3 to use three bytes. So
given the above code and the experiment (yes I could just add a bigger number)
| id |
id := LargePositiveInteger.
1 to: (16777215 + 50) do: [:each |
id := id digitAdd: 1].
id.
Given the comment it should overflow and the value be 50? This is not what the
result is. So shall the truncation be added again or at least the comment be
updated? The code will go from LargePositiveInteger to SmallInteger when
overflowing from three to four bytes but luckily
>>#value
...
replaceFrom: 1 to: 3 with: self class counterNext startingAt: 1
will even work when counterNext returns a SmallInteger. But given the old code
and the comment in the new code this is does not seem to function as intended?
kind regards
holger
PS: The other part is that >>#newCounter doesn't seem to be ever executed. On
first load >>#initialize will call >>#reset and on >>#shutDown: calls reset. So
the code to "randomize" the initial counter doesn't seem to work.
