On Friday 01 February 2008 18:51, Robert Hailey wrote:
>
> On Feb 1, 2008, at 12:33 PM, Alberto Bacchelli wrote:
>
> > Hi,
> >
> > trying some automatic test case generator on the code, I found that
> > there is a bug in freenet.support.BitArray.
> > It is not a problem in the Freenet code, but it seems a Java problem
> > (maybe only with the VM version I am using which is Java(TM) SE
> > Runtime
> > Environment (build 1.6.0_03-b05) ).
> >
> > if you run this test:
> >
> > public void testConstructorThrowsEOFException1() throws Throwable {
> > DataInputStream dis = new DataInputStream(new
> > ByteArrayInputStream("testString".getBytes()));
> > try {
> > new BitArray(dis);
> > fail("Expected EOFException to be thrown");
> > } catch (EOFException ex) {
> > assertEquals("ex.getClass()", EOFException.class,
> > ex.getClass());
> > assertThrownBy(DataInputStream.class, ex);
> > assertEquals("dis.available()", 0, dis.available());
> > }
> > }
> >
> > you will probably get a java.lang.OutOfMemoryError.
> >
> > This is caused by a bad value returned by readInt() in the following
> > code:
> >
> >
> > public BitArray(DataInputStream dis) throws IOException {
> > _size = dis.readInt();
> > _bits = new byte[(_size / 8) + (_size % 8 == 0 ? 0 : 1)];
> > dis.readFully(_bits);
> > }
> >
> > the simpliest way to solve this issue imho is to find a way to avoid
> > using readInt().
> >
> > Sback
>
> I'm not really sure this is so much a bug as garbage-in-garbage-out.
>
> By the code provided, the size for the bitarray is given first, then
> the raw data; it just so happens that when you translate the first
> several bytes of "testString" into an integer, it comes out to be very
> large number (more bytes than are available for allocation). Note that
> there *is* a legitimate bitarray data stream which will begin with
> "testString".asBytes(), it is probably just too large for practical use.
Do we use this anywhere, that is the question?
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