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Re: LZJU90 compression example(s)



On Sat, 19 Sep 1998 17:53:20 EDT, you said:
> Therefore, any comparision is not truely fair since I assume the Base64 code
> I am using has be optimized to its fullest potential by Microsoft whereas
> the LZJU90 code is not.

It is always bad to assume that production code has been optimized.

Do you have *any* reason to assume that Microsoft optimized this code?

Do you have any reason to even assume that the Microsoft code is in
fact a totally correct and bug-free Base64 encoder?  Have you stress-tested
it with various inputs? Does it Do The Right Thing in case of memory/disk
space exhaustion? (Try attaching an uncompressed GCC source tree tarball
and see what happens?)  Have you hand-checked the code for bogosity
such as un-needed debugging code inside the central loop?  Was the Microsoft
code either compiled with an optimizer that did CSE and code hoisting, or
was the code previously hand-tuned for this?

About all you've actually proven so far is that there's reason to suspect
that Microsoft has, in fact, NOT optimized this code - presumably because
they felt it was "fast enough" already, and they had other problems to deal
with, like making sure the program didn't induce a Blue Screen of Death....

-- 
				Valdis Kletnieks
				Computer Systems Senior Engineer
				Virginia Tech

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