[fpc-pascal] Porter Stemming for FPC 2.0

[Lance Boyle]

This is very interesting. I've always wondered if anyone did this on  
purpose, and I've always wondered what the big deal is with just  
adding array range checking to C. A company with tons of internal  
software development, and whose existence is made miserable by buffer  
under/over flows, could surely pull this off. For example, Microsoft  
could change the compilers that they use internally, and any  
programmers found to be depending on the persistence of memory "next  
to" an array would be taken out and shot.

I'm sure someone will respond, telling me why this would be a bad  
idea or impossible, but that's my two cents worth.

Lance


On Sep 16, 2005, at 4:55 PM, memsom wrote:

>> It's great that 2.0 is out!  Unfortunately it seems to break some
>> code I used for Porter Stemming because the code sometimes reads data
>> from a pchar at negative indexes.  Reportedly this works fine in
>> Delphi 5 and I don't seem to have trouble with Delphi 7 but it
>> generates RTEs using fpc 2.0.  (If this is a FAQ, forgive me, I've
>> been away from Free Pascal for a while...)
>>
>
> Reading PChars at negative indexes? Buffer underrun in other  
> words... This
> is absolutely not a good thing. If FPC is preventing buffer under and
> overrruns, then it is actually right, for once, and Delphi is wrong,
> wrong, wrong!
>
> A question... how do you know the memory at the negative index is  
> valid?
> Various factors (memory management, record alignement and poor  
> consistency
> in longterm projects) can alter what you are reading drastically.  
> Even if
> you *believe* you know what it is. This is the kind of horror story  
> I see
> sometimes in Legacy code that makes me wonder how the darn thing  
> _ever_
> worked all these years. You ask the guy maintaining it and he goes all
> mistical - "It just works, but no one remembers why.. we dare not  
> change
> it because last time somebody did anything to it the entive project  
> A/V'd
> every 30 seconds and died in a puff of green smoke."
>
> M
>
> M
This is very interesting. I've always wondered if anyone did this on  
purpose, and I've always wondered what the big deal is with just  
adding array range checking to C. A company with tons of internal  
software development, and whose existence is made miserable by buffer  
under/over flows, could surely pull this off. And surely it wouldn't  
break _that_ much code. For example, Microsoft could change the  
compilers that they use internally, and any programmers found to be  
depending on the persistence of memory "next to" an array would be  
taken out and shot.

I'm sure someone will respond, telling me why this would be a bad  
idea or impossible, but that's my two cents worth.

Lance