/*
 * Copyright (c) 2007 Bret S. Lambert <blambert@gsipt.net>
 *
 * Public domain.
 */

#include <libgen.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <errno.h>
#include <err.h>

int
main(void)
{
        char path[2 * PATH_MAX];
        char dname[128];
        const char *dir = "junk";
        const char *fname = "/file.name.ext";
        char *str;
        int i;

        /* Test normal functioning */
        strlcpy(path, "/", sizeof(path));
        strlcpy(dname, "/", sizeof(dname));
        strlcat(path, dir, sizeof(path)); 
        strlcat(dname, dir, sizeof(dname)); 
        strlcat(path, fname, sizeof(path));
        str = dirname(path);
        if (strcmp(str, dname) != 0)
                errx(1, "0: dirname(%s) = %s != %s", path, str, dname);

        /*
         * There are four states that require special handling:
         *
         * 1) path is NULL
         * 2) path is the empty string
         * 3) path is composed entirely of slashes
         * 4) the resulting name is larger than PATH_MAX
         *
         * The first two cases require that a pointer
         * to the string "." be returned.
         *
         * The third case requires that a pointer
         * to the string "/" be returned.
         *
         * The final case requires that NULL be returned
         * and errno * be set to ENAMETOOLONG.
         */
        /* Case 1 */
        str = dirname(NULL);
        if (strcmp(str, ".") != 0)
                errx(1, "1: dirname(NULL) = %s != .", str);

        /* Case 2 */
        strlcpy(path, "", sizeof(path));
        str = dirname(path);
        if (strcmp(str, ".") != 0)
                errx(1, "2: dirname(%s) = %s != .", path, str);

        /* Case 3 */
        for (i = 0; i < PATH_MAX - 1; i++)
                strlcat(path, "/", sizeof(path));       /* path cleared above */
        str = dirname(path);
        if (strcmp(str, "/") != 0)
                errx(1, "3: dirname(%s) = %s != /", path, str);

        /* Case 4 */
        strlcpy(path, "/", sizeof(path));               /* reset path */
        for (i = 0; i <= PATH_MAX; i += strlen(dir))
                strlcat(path, dir, sizeof(path));
        strlcat(path, fname, sizeof(path));
        str = dirname(path);
        if (str != NULL)
                errx(1, "4: dirname(%s) = %s != NULL", path, str);
        if (errno != ENAMETOOLONG)
                errx(1, "4: dirname(%s) sets errno to %d", path, errno);

        return (0);
}