Re: [StrongED] Testing StrongHelp 2.90b1 (Urgent)

[Peter Young <pnyoung@xxxxxxxxxxxx>]

On 21 Mar 2017  Fred Graute <fjgraute@xxxxxxxxx> wrote:

> In message <30ef682056.pnyoung@xxxxxxxxxxxxxxxxxxxx>
>           Peter Young <pnyoung@xxxxxxxxxxxx> wrote:

>> On 21 Mar 2017  Fred Graute <fjgraute@xxxxxxxxx> wrote:
>> 
>>> In message <mpro.on4bwl004yfpf0vz7.pittdj@xxxxxxxxxxxx>
>>>           David Pitt <pittdj@xxxxxxxxxxxx> wrote:
>> 
>>> [snip]
>> 
>>>> I have now seen the crash after looking at the NeXTBar 1.30 StrongHelp.
>>>> 
>>>> It is a bit weird, it does not immediately crash !StrongHelp, that happens
>>>> later on some other entirely innocent file.
>>>>
>>>> Paint gives a "Bad MODE" error but !StrongHlp can render it as can
>>>> !Draw. A
>>>> "corrected" version of the file can be extracted from !Draw after which
>>>> there are no more crashes (yet?).
>> 
>>> The sprite itself is actually fine. It's the data in the squash file
>>> that is corrupted, there's some spurious data at the end.
>> 
>>> StrongHelp allocates space based on the original length that's given in
>>> the squash header. Because of the extra data the allocated output buffer
>>> is overrun. This corrupts the list of free blocks so next time SH needs
>>> to allocate memory (eg when opening a manual) it may hit the damaged
>>> part of this list and abort.
>> 
>>> Extracting the sprite and re-squashing it gets rid of the spurious data.
>>> This stops the corruption of the list of free blocks and therefore SH no
>>> longer crashes on manuals opened after the NeXTBar manual.
>> 
>> Thanks again, Fred. I've been having a bit of a chaotic time with the
>> NeXTBar manual on this ARMX6 not always being willing to show its
>> contents,

> You mean Shift-doubleclick doesn't work? It should provided that
> StrongHelp is running.

Now, that would explain my problem. It does work when StrongHelp is 
running, but I was trying sometimes when it wasn't running! Is this 
documented anywhere? I tried searching, but never came up with an 
answer, and couldn't find anything in StrongHelp's own StrongHelp 
file. Probably my fault for not looking hard enough.

>> and I wondered how I would extract the sprite when all I got trying to
>> open the sprite file was the "bad mode" message.

> As David Pitt pointed out: unsquash the file then drop the sprite file
> in Draw and save the sprite from there. The recovered sprite can then
> copied back to the manual (squashed or not).

Sorry, missed that advice.

>> I looked at the copy of NeXTBar on VRPC, where I could see the
>> contents, and saw that the sprite there wasn't squashed. I then
>> managed to open the manual on the ARMX6, and copied over the
>> unsquashed sprite. This seems to let the manual open without the
>> sprite's being squashed, so I wonder if the squash is necessary.

> Squashing is not at all necessary but it does make the manual smaller.

I've now squashed the sprite file.

>> Anyway, the problem seems now to be solved, with many thanks.

> Thanks for reporting it. Taught me that dodgy squash files can bring
> StrongHelp down. Oh, and I found a bug in StrongED Dump mode handling
> along the way. All in all it was a useful bit of digging around.

I'm glad about that. I think I've said before, the bane of a 
programmer's life must be the silly things that users do, which the 
programmer had never thought they would do!

Best wishes, and thanks again,

Peter.

-- 
Peter Young (zfc Ir) and family
Prestbury, Cheltenham, Glos. GL52, England
http://pnyoung.orpheusweb.co.uk
pnyoung@xxxxxxxxxxxx

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