usr/src/lib/libcompat/4.3/lsearch.c

/*
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Roger L. Snyder.
 *
 * %sccs.include.redist.c%
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)lsearch.c   8.1 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>
#include <unistd.h>

static char *linear_base();

char *
lsearch(key, base, nelp, width, compar)
        char *key, *base;
        u_int *nelp, width;
        int (*compar)();
{
        return(linear_base(key, base, nelp, width, compar, 1));
}

char *
lfind(key, base, nelp, width, compar)
        char *key, *base;
        u_int *nelp, width;
        int (*compar)();
{
        return(linear_base(key, base, nelp, width, compar, 0));
}

static char *
linear_base(key, base, nelp, width, compar, add_flag)
        char *key, *base;
        u_int *nelp, width;
        int (*compar)(), add_flag;
{
        register char *element, *end;

        end = base + *nelp * width;
        for (element = base; element < end; element += width)
                if (!compar(element, key))              /* key found */
                        return(element);

        if (!add_flag)                                  /* key not found */
                return(NULL);

        /*
         * The UNIX System User's Manual, 1986 edition claims that
         * a NULL pointer is returned by lsearch with errno set
         * appropriately, if there is not enough room in the table
         * to add a new item.  This can't be done as none of these
         * routines have any method of determining the size of the
         * table.  This comment was isn't in the 1986-87 System V
         * manual.
         */
        ++*nelp;
        bcopy(key, end, (int)width);
        return(end);
}