usr/src/lib/libc/string/strsep.c

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#include <sys/cdefs.h>
#include <string.h>
#include <stdio.h>

#if defined(LIBC_SCCS) && !defined(lint)
static const char sccsid[] = "@(#)strsep.c      5.4 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

/*
 * Get next token from string *stringp, where tokens are nonempty
 * strings separated by characters from delim.
 *
 * Writes NULs into the string at *stringp to end tokens.
 * delim need not remain constant from call to call.
 * On return, *stringp points past the last NUL written (if there might
 * be further tokens), or is NULL (if there are definitely no more tokens).
 *
 * If *stringp is NULL, strtoken returns NULL.
 */
char *
strsep(stringp, delim)
        register char **stringp;
        register const char *delim;
{
        register char *s;
        register const char *spanp;
        register int c, sc;
        char *tok;

        if ((s = *stringp) == NULL)
                return (NULL);
        for (tok = s;;) {
                c = *s++;
                spanp = delim;
                do {
                        if ((sc = *spanp++) == c) {
                                if (c == 0)
                                        s = NULL;
                                else
                                        s[-1] = 0;
                                *stringp = s;
                                return (tok);
                        }
                } while (sc != 0);
        }
        /* NOTREACHED */
}