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From "Andrew Zhang" <zhanghuang...@gmail.com>
Subject Re: [classlib][luni] Problem with java.io.OutputStream
Date Tue, 15 Aug 2006 02:13:46 GMT
On 8/15/06, Geir Magnusson Jr <geir@pobox.com> wrote:
>
> When looking at HARMONY-1156, it became clear that our
> java.io.OutputStream isn't right.
>
> I'd like to make the following changes :
>
> Follow the spec so that an IndexOOBE is thrown when :
>
> a) offset is negative or
> b) len is negative or
> c) off + len > buff.length
>
> So in the case of
>
>   write( byte[count], count, 0);
>
> for any value of count >= 0, then none of the conditions are true, and
> it should simply [quickly] return.
>
> Now, the spec says that if the array is null, then a NPE should be
> thrown, but this doesn't happen in the RI when len = 0.


Yes. It's a common exception throw sequence of RI.
Vladimir Ivanov has provided a util patch for such exception check, iirc.
For detail, please refer to Harmony-942 (
http://issues.apache.org/jira/browse/HARMONY-942).
Following code snippet is copied from Harmony-942 patch. Does it work for
this problem?
public static void assertArrayIndex(byte[] array, int offset, int length) {
  if (offset < 0 || length < 0) {
   throw new IndexOutOfBoundsException(Msg.getString("K0006"));
  }
  if ((long)offset+(long)length >  array.length) {
   throw new IndexOutOfBoundsException(Msg.getString("K00ae"));
  }
 }

Of course, If long cast looks not elegant, we can change the code as
following:
 "if (offset >  array.length-length) ".


This seems to be a reasonable thing to do, and therefore I think that we
> should match the RI here, and not the spec.
>
> Comments?
>
> geir
>
>
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>


-- 
Andrew Zhang
China Software Development Lab, IBM

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