fold strn{casecmp,cat,cmp,cpy}.3 into str{casecmp,cat,cmp,cpy}.3

[unix-history] / usr / src / lib / libc / string / strtok.c

/*
* Copyright (c) 1988 Regents of the University of California.
* All rights reserved.
*
* %sccs.include.redist.c%
*/

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)strtok.c    5.7 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <stddef.h>
#include <string.h>

char *
strtok(s, delim)
       register char *s, *delim;
{
       register char *spanp;
       register int c, sc;
       char *tok;
       static char *last;


       if (s == NULL && (s = last) == NULL)
               return (NULL);

       /*
        * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
        */
cont:
       c = *s++;
       for (spanp = delim; (sc = *spanp++) != 0;) {
               if (c == sc)
                       goto cont;
       }

       if (c == 0) {           /* no non-delimiter characters */
               last = NULL;
               return (NULL);
       }
       tok = s - 1;

       /*
        * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
        * Note that delim must have one NUL; we stop if we see that, too.
        */
       for (;;) {
               c = *s++;
               spanp = delim;
               do {
                       if ((sc = *spanp++) == c) {
                               if (c == 0)
                                       s = NULL;
                               else
                                       s[-1] = 0;
                               last = s;
                               return (tok);
                       }
               } while (sc != 0);
       }
       /* NOTREACHED */
}