[squeak-dev] MultiByteFileStream upToAll: strange bug
Bob Arning
arning315 at comcast.net
Sun Jan 21 03:00:47 UTC 2018
The problem occurs when crossing the 2kb size of the StandardFileStream
variable <collection>. The </A> you were looking for straddled that
boundary. Here is a simple test:
============
test1
"
self test1
"
| f answer result fn |
fn := 'foo.foo.foo'.
FileDirectory default deleteFileNamed: fn.
f := MultiByteFileStream fileNamed: fn.
{1000. 1000. 1000. 1000} do: [ :len |
len timesRepeat: [f nextPutAll: 'a'].
f nextPutAll: 'bbb'.
].
f close.
result := OrderedCollection new.
f := MultiByteFileStream fileNamed: fn.
[f atEnd] whileFalse: [
answer := f upToAll: 'bbb'.
result add: {answer size. f position. "answer"}
].
f close.
^result
=========
- write 1000 a's followed by 3 b's
- do this 4 times
- read it back by using upToAll: 'bbb'
- expect 4 1000-byte strings as the result
BUT you get
an OrderedCollection(
#(1000 1003)
#(1000 2006)
#(2006 3009)
#(1003 4012))
instead. The positions are right, but the lengths returned are not.
On 1/20/18 4:24 PM, Bernhard Pieber wrote:
> Hi everyone,
>
> I think I found a really strange bug in MultiByteFileStream. I am on macOS Sierra and used the latest VM from bintray and an updated trunk image.
>
> I try to parse anchors from a UTF-8 encoded HTML file (see attachment). It uses a MultiByteFileStream with a UTF8TextConverter.
>
> Here is the code that shows the bug:
>
> FileStream readOnlyFileNamed: 'test.html' do: [:stream |
> | result |
> result := OrderedCollection new.
> [stream atEnd] whileFalse: [
> stream match: '<A HREF="'.
> result add: (stream upToAll: '</A>')].
> result at: 13
> ].
>
> It answers the following string:
> 'https://www.europa.de/produkte/lebensversicherung">Darlehen sichern: Variable Risiko-Lebensversicherung</A>
> <DT><A HREF="http://orf.at/stories/2358210/2358209/">Banken im Zinsdilemma</A>
> </DL><p>
> </DL><p>
> </DL><p>
> </HTML>
> '
>
> You can see that it did not stop at the </A> as it should have but answers the rest of the file. The strange thing is that the next anchor looks like this:
> 'http://orf.at/stories/2358210/2358209/">Banken im Zinsdilemma</A>
> </DL><p>
> </DL><p>
> </DL><p>
> </HTML>
> '
> So it read part of the file again.
>
> I tried making the file smaller but the bug goes away then.
>
> As a cross check when I read the whole file at once it parses correctly.
>
> FileStream readOnlyFileNamed: 'test.html' do: [:fileStream |
> | stream result |
> stream := fileStream contentsOfEntireFile readStream.
> result := OrderedCollection new.
> [stream atEnd] whileFalse: [
> stream match: '<A HREF="'.
> result add: (stream upToAll: '</A>')].
> result at: 13
> ].
>
> Any ideas anyone?
>
> Bernhard
>
>
>
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