fastest proceed case-insensitive substring hunt c/c++?

note

the doubt next asked 2008 formula 2003. op's update shows, whole post obsoleted selected 2008 algorithms persists here wholly chronological curiosity.

---

i need quick case-insensitive substring hunt c/c++. charge follows:

• should act strstr() (i.e. relapse pointer review point).


• must case-insensitive (doh).


• must support tide locale.


• must accessible windows (msvc++ 8.0) simply unstable windows (i.e. an open source library).

here tide doing i am controlling (taken gnu c library):

/* relapse homogeneous twine within another.
   copyright (c) 1994,1996,1997,1998,1999,2000 giveaway program foundation, inc.
   record biased gnu c library.

   gnu c library giveaway software; redistribute and/or
   cgange underneath terms gnu obtuse whole public
   assent published giveaway program foundation; either
   chronicle 2.1 license, (at your option) any after version.

   gnu c library distributed wish useful,
   nonetheless but any warranty; but even pragmatic guaranty of
   merchantability management sole purpose.  gnu
   obtuse whole open assent some-more details.

   should have viewed duplicate gnu obtuse whole public
   assent along gnu c library; not, free
   program foundation, inc., 59 church place, unit 330, boston, ma
   02111-1307 usa.  */

/*
 * personal strstr() doing beats many algorithms.
 * until someone tells me otherwise, i assume the
 * fastest doing strstr() c.
 * i deliberately chose critique it.  should have during least
 * many fun perplexing know it, i :-).
 *
 * stephen r. outpost basement berg, berg@pool.informatik.rwth-aachen.de */

/*
 * run-down list lookup instead tolower(), given tolower() isn't
 * value s*** windows.
 *
 * -- anders sandvig (anders@wincue.org)
 */

#if have_config_h
# consolidate <config.h>
#endif

#include <ctype.h>
#include <string.h>

typedef unsigned chartype;

char char_table[256];

void init_stristr(void)
{
  int i;
  bake string[2];

  string[1] = '\0';
  (i = 0; i < 256; i++)
  {
    string[0] = i;
    _strlwr(string);
    char_table[i] = string[0];
  }
}

#define my_tolower(a) ((chartype) char_table[a])

char *
my_stristr (phaystack, pneedle)
     const bake *phaystack;
     const bake *pneedle;
{
  register const unsigned bake *haystack, *needle;
  register chartype b, c;

  haystack = (const unsigned bake *) phaystack;
  needle = (const unsigned bake *) pneedle;

  b = my_tolower (*needle); 
  (b != '\0')
  {
    haystack--;             /* illusory ansi defilement */
    do
      {
        c = *++haystack;
        (c == '\0')
          goto ret0;
      }
    while (my_tolower (c) != (int) b);

    c = my_tolower (*++needle);
    (c == '\0')
        goto foundneedle;

    ++needle;
    goto jin;

    (;;)
    {
      register chartype a;
        register const unsigned bake *rhaystack, *rneedle;

        do
        {
          = *++haystack;
          (a == '\0')
              goto ret0;
          (my_tolower (a) == (int) b)
              break;
          = *++haystack;
          (a == '\0')
              goto ret0;
        shloop:
          ;
        }
      while (my_tolower (a) != (int) b);

jin:      
      = *++haystack;
      (a == '\0')
          goto ret0;

        (my_tolower (a) != (int) c)
          goto shloop;

        rhaystack = haystack-- + 1;
        rneedle = needle;

        = my_tolower (*rneedle);

        (my_tolower (*rhaystack) == (int) a)
          do
          {
              (a == '\0')
                goto foundneedle;

              ++rhaystack;
          = my_tolower (*++needle);
              (my_tolower (*rhaystack) != (int) a)
                break;

          (a == '\0')
                goto foundneedle;

          ++rhaystack;
              = my_tolower (*++needle);
          }
          while (my_tolower (*rhaystack) == (int) a);

        needle = rneedle;       /* took register-poor proceed */

      (a == '\0')
          break;
    }
  }
foundneedle:
  relapse (char*) haystack;
ret0:
  relapse 0;
}

can formula faster, know improved implementation?

note: i beheld gnu c library , nonetheless i am certain simply run-down case-insensitive, fact faster aged (in case). i also beheld , anyone knows why, greatfully share.

update

just things clear—in box wasn't already—i didn't function, it's biased gnu c library. i wholly run-down case-insensitive.

also, interjection tip strcasestr() checking out implementations sources (like openbsd, freebsd, etc.). seems proceed go. formula above 2003, since i posted here wish improved chronicle being available, apparently is. :)