[9] RFR(XS): 8076625: IndexOutOfBoundsException in HeapByteBufferTest.java

[Vladimir Kozlov]

Looks good.

Thanks,
Vladimir

On 4/10/15 3:42 AM, Tobias Hartmann wrote:
> Hi Vladimir,
>
> On 09.04.2015 18:22, Vladimir Kozlov wrote:
>> I also asked to use Utils::getRandomInstance() to get reproducible results.
>
> Sorry, I missed that. Here is the new webrev:
>
> http://cr.openjdk.java.net/~thartmann/8076625/webrev.01/
>
> I also noticed that the sizes of short and char reads passed to 'randomOffset' are too large (4 instead of 2). Fixed it.
>
> Best,
> Tobias
>
>
>> Thanks,
>> Vladimir
>>
>>
>> On 4/9/15 5:10 AM, Tobias Hartmann wrote:
>>> Hi,
>>>
>>> please review the following patch.
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-8076625
>>> http://cr.openjdk.java.net/~thartmann/8076625/webrev.00/
>>>
>>> Problem:
>>> A random offset to access in a byte array is computed by
>>>
>>>     int randomOffset(SplittableRandom r, MyByteBuffer buf, int size) {
>>>       return abs(r.nextInt()) % (buf.capacity() - size);
>>>     }
>>>
>>> The call to r.nextInt() may return Integer.MIN_VALUE (-2147483648) and the corresponding absolute value (+2147483648) does not fit into an int and will overflow back to -2147483648. As a result the returned offset is negative.
>>>
>>> Solution:
>>> Use nextInt(int n) to set the limit of the random value.
>>>
>>> Testing:
>>> Failing testcase and JPRT.
>>>
>>> Thanks,
>>> Tobias
>>>