strtok.c

/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 * Copyright 1993 OpenVision Technologies, Inc., All Rights Reserved
 *
 */

/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. Neither the name of the University nor the names of its
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

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

/*
 * Function: nstrtok
 *
 * Purpose: the same as strtok ... just different. does not deal with
 *          multiple tokens in row.
 *
 * Arguments:
 *      s           (input) string to scan
 *      delim       (input) list of delimiters
 *      <return value> string or null on error.
 *
 * Requires:
 *      nuttin
 *
 * Effects:
 *      sets last to string
 *
 * Modifies:
 *      last
 *
 */

char *
nstrtok(char *s, const char *delim)
{
    const char *spanp;
    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).
     */
#ifdef OLD
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;
#else
    tok = s;
#endif

    /*
     * 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 */
}