Re: [perl-win32-gui-hackers] Constants and hashing [Was: Win32::GUI::Dialog() failure]

[Jeremy W. <jez...@ho...>]

>>our original discussions until now, I think it may be more worthwhile to
>>   figure out how to make _all_ 18000 constants available to Win32::GUI
>>programs, without paying a huge price in memory.  Those constants that
>>actually get used get cached in the stash anyway...
>>
>>
>>    If speed isn't the issue then a binary search has  ...
>
>It is difficult or impossible to do a binary search of compressed data... 
>so if space is the overriding issue, compression is the overriding answer, 
>and linear searching becomes the only practical search technique.  To avoid 
>linear searching of the complete set, a

My 2 cents:)

We have 2 issues:

1) Performance.

2) Memory requirements.

Personally, the performance issue is a none event. I did some timings a 
while back, and the constant lookup logic could be several orders of 
magnitude slower than the current solution and it wouldn't make any 
difference to how a Win32-GUI application would perform. This is because the 
constant code isn't called often enough to make any difference.

Personally, the memory issue is a main problem. I like the idea of having 
all 18000 constants available to  Win32::GUI (if all the constants are 
available, then the module would also be useful for none Win32-GUI modules), 
but at what cost? 50k? 100k? 200k? Think about it for a moment - what would 
you sacrifice? Perhaps it's worth setting some target to aim for?

The binary search is a good idea - and I can think of a ways to make it work 
with compressed data - but we're still talking quite a lot of memory. If 
each constant (including the text and value) is:

average 10 bytes each = total 180,000 bytes
average 20 bytes each = total 360,000 bytes
...

Now, for some cases, 360k is a drop in the ocean - my app runs at 50 meg 
before it's done anything, with the exe coming in at 6 megs - but for a 20 
line utility script, having to load the dll holding the constants could be 
over-kill...

Perhaps less common constant text/values could be stored as a file, with a 
fast binary search lookup?

Cheers,

jez.