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Posted to dev@apex.apache.org by Munagala Ramanath <ra...@datatorrent.com> on 2017/02/09 16:18:40 UTC

Re: Infinite loop in CircularBuffer constructor (corner case)

Created https://github.com/DataTorrent/Netlet/issues/60 and
pull request https://github.com/DataTorrent/Netlet/pull/59

Ram

On Sun, Jan 29, 2017 at 6:42 PM, Vlad Rozov <v....@datatorrent.com> wrote:

> Netlet is not an Apache project. Please open issue on github
> https://github.com/DataTorrent/netlet/issues.
>
> Thank you,
>
> Vlad
>
> On 12/22/16 18:02, Munagala Ramanath wrote:
>
>> Actually, this will happen whenever the parameter n satisfies: 2**30 < n
>> <=
>> Integer.MAX_VALUE
>>
>> Ram
>>
>> On Thu, Dec 22, 2016 at 5:34 PM, Munagala Ramanath <ra...@datatorrent.com>
>> wrote:
>>
>> In Netlet CircularBuffer constructor, we have an infinite loop if the
>>> first parameter (*n*)
>>> is *Integer.MAX_VALUE* because the loop counter left-shifts 1 till it
>>> drops into the sign
>>> bit at which point the value is negative and fails the loop exit test.
>>> The
>>> next left shift
>>> yields 0 which, of course, stays that way forever; here is the fragment:
>>>
>>> *    int i = 1;*
>>> *    while (i < n) {*
>>> *      i <<= 1;*
>>> *    }*
>>>
>>> Ram
>>>
>>>
>