Re: [Libclc-developers] new function: clc_strrev

[<bo...@me...>]

Hallvard B Furuseth wrote:
> Bjørn Augestad writes:
> 
>>We can't have a string module without a strrev function, can we?
>>I could not find a proposal for one on google, so here is my version.
>>q1: Do we need it?
> 
> 
> I don't think so.  I can only remember needing a rev function once or
> twice in my life.  I have heroically refrained from posting a few nice
> libclc functions I've rarely if ever needed myself:-)
> 

Some sales pitches for clc_strrev. :-)

1. It seems to be a common problem for newbies to reverse a string, lots
of people have asked about this over the years. We can help them out by
providing it.

2. Microsoft has one (_strrev), ANSI C does not. clc_strrev can aid
portability.

3. Some functions can be implemented in a clearer way if we have a
clc_strrev. Consider the clc_ultostr() which in the latest version
writes from the end of buffer to the beginning and then calls memmove to
adjust the buffer. clc_ultostr() could be changed to writing from the
beginning of the buffer and then just reverse the output before
returning. Here's a quick&dirty implementation :

int clc_ultostr(char *ptr, size_t size, unsigned long num, int base)
{
         const char *sym = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
         char* sp;

         sp = ptr;
         size--; /* reserve one for \0 */
         do {
           *sp++ = sym[num % base];
           num /= base;
         } while (num > 0 && size-- > 0);

         if(num > 0)
           return 0;

         *sp = '\0';
         clc_strrev(ptr);
         return 1;
}

I ran my test program with both versions. The clc_strrev version is 5%
faster on one of my machines than the original which uses memmove. ;-)

I think you should post the nice functions as well. Never know if
someone needs them or suddenly finds a new way of doing things. :-)

-- 
boa

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