/*      $OpenBSD: telldir.c,v 1.4 2013/11/03 00:20:24 schwarze Exp $    */

/*      Written by Otto Moerbeek, 2006,  Public domain. */

#include <sys/types.h>
#include <dirent.h>
#include <err.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>

#include "utils.h"

#define NFILES 1000

static void
longloop(DIR *dp, int i)
{
        struct dirent *f;
        char file[PATH_MAX];
        long pos, t, remember = -1;

        rewinddir(dp);
        snprintf(file, sizeof file, "%d", i);

        /* Scan through all files, remember where file i is. */

        for (;;) {
                pos = telldir(dp);
                f = readdir(dp);
                if (f == NULL)
                        break;
                if (strcmp(file, f->d_name) == 0)
                        remember = pos;
        }
        if (remember == -1)
                errx(1, "remember %s", file);

        /* Go back to i, checking seekdir, telldir and readdir. */

        seekdir(dp, remember);
        if ((t = telldir(dp)) != remember)
                errx(1, "tell after seek %s %ld != %ld", file, t, remember);
        if ((t = telldir(dp)) != remember)
                errx(1, "tell after tell %s %ld != %ld", file, t, remember);
        f = readdir(dp);
        if (f == NULL)
                errx(1, "readdir %s at %ld", file, remember);

        if (strcmp(f->d_name, file) != 0)
                errx(1, "name mismatch: %s != %s", f->d_name, file);
}

void
longseek(void)
{
        DIR *dp;
        int i;

        createfiles(NFILES);

        dp = opendir("d");
        if (dp == NULL)
                err(1, "longseek: opendir");

        for (i = 0; i < NFILES; i++)
                longloop(dp, (i + NFILES/2) % NFILES);

        closedir(dp);
        delfiles();
}