BSD 4_4 release

[unix-history] / usr / src / sys / tahoe / stand / vdformat / online / strtok.c

#ifndef lint
static char sccsid[] = "@(#)strtok.c    1.1 (Berkeley/CCI) 7/5/86";
#endif

/*      @(#)strtok.c    1.2     */
/*      3.0 SID #       1.2     */
/*LINTLIBRARY*/
/*
* uses strpbrk and strspn to break string into tokens on
* sequentially subsequent calls.  returns NULL when no
* non-separator characters remain.
* `subsequent' calls are calls with first argument NULL.
*/

#define NULL    (char*)0

extern int strspn();
extern char *strpbrk();

char *
strtok(string, sepset)
char    *string, *sepset;
{
       register char   *p, *q, *r;
       static char     *savept;

       /*first or subsequent call*/
       p = (string == NULL)? savept: string;

       if(p == 0)              /* return if no tokens remaining */
               return(NULL);

       q = p + strspn(p, sepset);      /* skip leading separators */

       if(*q == '\0')          /* return if no tokens remaining */
               return(NULL);

       if((r = strpbrk(q, sepset)) == NULL)    /* move past token */
               savept = 0;     /* indicate this is last token */
       else {
               *r = '\0';
               savept = ++r;
       }
       return(q);
}