C Programming - Extract Token from Strings

glibc implementation of strtok for i386 platform.



static char *olds;
void *rawmemchr (const void *s, int c)
{
  register unsigned long int d0;
  register unsigned char *res;
  __asm__ __volatile__
    ("cld\n\t"
     "repne; scasb\n\t"
     : "=D" (res), "=&c" (d0)
     : "a" (c), "0" (s), "1" (0xffffffff),
       "m" ( *(struct { char __x[0xfffffff]; } *)s)
     : "cc");
  return res - 1;
}



char *strtok (char *s, const char *delim)
{
  char *token;
  if (s == NULL) s = olds;
  
/* Scan leading delimiters.  */
  s += strspn (s, delim);
  if (*s == '\0') {
      olds = s;
      return NULL;
  }

  /* Find the end of the token.  */
  token = s;
  s = strpbrk (token, delim);
  if (s == NULL)
    /* This token finishes the string.  */
    olds = rawmemchr (token, '\0');
  else {
      /* Terminate the token and make OLDS point past it.  */
      *s = '\0';
      olds = s + 1;
  }
  return token;
}



Notes:

This was extracted from glibc-2.3.6 (sysdeps/generic/strtok.c)

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