Bug in Compression-ZLib in VW7.7?

Hi,

I think there's a bug in the Compression-ZLib package in this method:

OS.ZLib.GZipReadStream>>checkCrcAndLength

                "This class futzing is insanity; see AR46615"

                | fileCrcAndLength endOfCompressedInput |

                fileCrcAndLength := UninterpretedBytes new: 8.

                endOfCompressedInput := interface next_in datum - inputBuffer fixedHeapAddress.

                inputLimit - endOfCompressedInput >= 8

                               ifTrue: [ fileCrcAndLength replaceBytesFrom: 1 to: 8 with: inputBuffer startingAt: endOfCompressedInput  + 1 ]

                               ifFalse: [ | footerSplit |

                                               "This means that some (possibly none) of the footer (crcAndLength) is already in the input buffer and some is still sitting in the sourceStream. We need to figure out what is the split and put the two pieces together. It's also possible to just skip back in the sourceStream based on the split value, but I don't think that imposing positionability on the sourceStream just to make this one bit a little easier is worth it."

                                               footerSplit := inputLimit - endOfCompressedInput. "how much of the footer is already in the inputBuffer"

                                               fileCrcAndLength replaceBytesFrom: 1 to: footerSplit with: inputBuffer startingAt: endOfCompressedInput + 1.

                                               sourceStream next: 8 - footerSplit into: fileCrcAndLength startingAt: footerSplit + 1].

                crc ~= (fileCrcAndLength unsignedLongAt: 1 bigEndian: false) ifTrue:

                               [self error: 'file crc error'].

                interface total_out ~= (fileCrcAndLength unsignedLongAt: 5 bigEndian: false) ifTrue:

                               [self error: 'file length error']

The parts in red indicate the problem. It creates an UninterpretedBytes and later on /sometimes/ tries to copy contents from the sourceStream into it. However, this 2^nd method uses at:put: to write bytes into the UninterpretedBytes and this is not implemented on that class, resulting in this crash:

[1]          UninterpretedBytes(Object)>>error:

[2]          UninterpretedBytes(Object)>>shouldNotImplement

[3]          UninterpretedBytes>>at:put:

[4]          ReadStream(PositionableStream)>>next:into:startingAt:

[5]          OS.ZLib.GZipReadStream>>checkCrcAndLength

[6]          OS.ZLib.GZipReadStream>>nextBuffer

[7]          OS.ZLib.GZipReadStream(OS.ZLib.InflateStream)>>endTest

[8]          OS.ZLib.GZipReadStream(OS.ZLib.InflateStream)>>atEnd

[9]          OS.ZLib.GZipReadStream(Stream)>>upToEnd

One of our customers has had the problem but I cannot reproduce it.

Is there a fix for it? (This is in VW7.7).

Thanks,

Mark