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From: Malcolm McLean <malcolm.arthur.mclean@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: realloc() - frequency, conditions, or experiences about
 relocation?
Date: Tue, 18 Jun 2024 11:46:36 +0100
Organization: A noiseless patient Spider
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On 18/06/2024 11:19, Malcolm McLean wrote:
> On 18/06/2024 08:09, Tim Rentsch wrote:
>> Anton Shepelev <anton.txt@g{oogle}mail.com> writes:
>>
>>> Ben Bacarisse to Malcolm McLean:
>>>
>>>> [next is a comment from Malcolm]
>>>>
>>>>> Your strategy for avoiding these extremes is exponential
>>>>> growth.
>>>>
>>>> It's odd to call it mine.  It's very widely know and used.
>>>> "The one I mentioned" might be less confusing description.
>>>
>>> I think it is a modern English idiom, which I dislike as
>>> well.  StackOverflow is full of questions starting like:
>>> "How do you do this?" and "How do I do that?"  They are
>>> informal ways of the more literary "How does one do this?"
>>> or "What is the way to do that?"
>>
>> I have a different take here.  First the "your" of "your
>> strategy" reads as a definite pronoun, meaning it refers
>> specifically to Ben and not to some unknown other party.
>> (And incidentally is subtly insulting because of that,
>> whether it was meant that way or not.)
>>
>> Second the use of "you" to mean an unspecified other person
>> is not idiom but standard usage.  The word "you" is both a
>> definite pronoun and an indefinite pronoun, depending on
>> context.  The word "they" also has this property.  Consider
>> these two examples:
>>
>>     The bank downtown was robbed.  They haven't been caught
>>     yet.
>>
>>     They say the sheriff isn't going to run for re-election.
>>
>> In the first example "they" is a definite pronoun, referring
>> to the people who robbed the bank.  In the second example,
>> "they" is an indefinite pronoun, referring to unspecified
>> people in general (perhaps but not necessarily everyone).
>> The word "you" is similar:  it can mean specifically the
>> listener, or it can mean generically anyone in a broader
>> audience, even those who never hear or read the statement
>> with "you" in it.
>>
>> The word "one" used as a pronoun is more formal, and to me
>> at least often sounds stilted.  In US English "one" is most
>> often an indefinite pronoun, either second person or third
>> person.  But "one" can also be used as a first person
>> definite pronoun (referring to the speaker), which an online
>> reference tells me is chiefly British English.  (I would
>> guess that this usage predominates in "the Queen's English"
>> dialect of English, but I have very little experience in
>> such things.)
>>
>> Finally I would normally read "I" as a first person definite
>> pronoun, and not an indefinite pronoun.  So I don't have any
>> problem with someone saying "how should I ..." when asking
>> for advice.  They aren't asking how someone else should ...
>> but how they should ..., and what advice I might give could
>> very well depend on who is doing the asking.
> 
> Ben said
>  > Restore snipped Ben upthread
> "In practice, the cost is usually
> moderate and can be very effectively managed by using an exponential
> allocation scheme: at every reallocation multiply the storage space by
> some factor greater than 1 (I often use 3/2, but doubling is often used
> as well)."
> 
> So it's open and shut, and no two ways about it. Ben's strategy is 
> exponential growth. And to be fair I use that strategy myself in 
> functions like fslutp(). It's only not Ben's strategy if we mean to 
> imply that Ben was the first person to use expoential growth, or the 
> first to understand the mathematical implications, and of course that's 
> not the case. It was all worked out by Euler long before any of us were 
> born.
> 
> The question is whether we can be a bit more rigorous than "we need 
> exonential growth, let's double on each reallocation. Actually, that 
> looks a bit greedy. Try 3/2". And we can do that. We can put it on a 
> sounder statistical footing. Whether it actually worth it or not is a 
> different matter.
> 
Here are some real stats on file sizes, in case anone is interested.

Data set, / OS Log-normal median & mean, Arithmetic mean, 50% occupied by
(< mean)

whole data set,   9.0 KB,   730 KB, 1.5 MB < 5.4 KB
Mac OS            8.0 KB,   533 KB, 1.4 MB < 4.9 KB
Windows           11.5 KB,  1.0 MB, 1.7 MB < 8.3 KB
GNU/Linux         10.8 KB,  1.7MB,  2.2 MB < 4.8 KB

https://www.researchgate.net/publication/353066615_How_Big_Are_Peoples%27_Computer_Files_File_Size_Distributions_Among_User-managed_Collections

-- 
Check out my hobby project.
http://malcolmmclean.github.io/babyxrc