Re: [xml] RAW && NXT with strncmp()

[Steve Williams <swilliams rinax com>]

Hi,

Depending on the frequency of a match NOT occuring, the original code 
could be significantly faster.  The first condition that did not match 
causes the remaining comparisons to not happen.  If in 90% of the cases 
(I have no idea the context of this code), the match is going to fail on 
the (RAW=='<'), then the other two comparisons would NOT happen.

This compared with the overhead of a function call every time...  but 
then I'm an "old school" C programmer who considers things like speed.

I'd be inclined to make a #define for the comparison if it occurs in so 
many places.  But that's just me...

Cheers,
Steve

Igor Izvarin wrote:

> Hi community,
>  
> I think this is the question mainly to Daniel Veillard, but ... :-)))
>  
> I found 79 (more or less) places in the parser.c code that contains 
> fragments like this:
> if ((RAW == '<') && (NXT(1) == '?') && (NXT(2) == 'x') && ....)
>  
> Its functionality is exact repetition of the functionality of the 
> strncmp() standard function.
> if (strncmp(RAW, "<?x...", n) == 0) ...
>  
> This function can be expanded inline using the #pragma intrinsic(...) 
> instruction.
>  
> For my opinion this change will improve the code readability and 
> maintenance, will reduce the source code size and object code size.
>  
> What is your opinion on this?
>  
> With best regards,
> Igor Izvarin