/*      $NetBSD: offtab.h,v 1.3 2017/04/16 23:50:40 riastradh Exp $     */

/*-
 * Copyright (c) 2014 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Taylor R. Campbell.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef VNDCOMPRESS_OFFTAB_H
#define VNDCOMPRESS_OFFTAB_H

#include <sys/cdefs.h>

#include <stdbool.h>
#include <stdint.h>

#include "common.h"

struct offtab {
        uint32_t        ot_n_offsets;
        uint32_t        ot_window_size;
        uint32_t        ot_window_start;
        uint64_t        *ot_window;
        uint32_t        ot_blkno;
        int             ot_fd;
        off_t           ot_fdpos;
        void            (*ot_report)(const char *, ...) __printflike(1,2);
        void            (*ot_reportx)(const char *, ...) __printflike(1,2);
        enum offtab_mode {
                OFFTAB_MODE_NONE,
                OFFTAB_MODE_READ,
                OFFTAB_MODE_WRITE,
        }               ot_mode;
};

#define OFFTAB_MAX_FDPOS                                                      \
        ((off_t)(MIN(OFF_MAX, UINT64_MAX) -                                   \
            (off_t)MAX_N_OFFSETS*sizeof(uint64_t)))

void            offtab_init(struct offtab *, uint32_t, uint32_t, int, off_t);
void            offtab_destroy(struct offtab *);

bool            offtab_transmogrify_read_to_write(struct offtab *, uint32_t);

bool            offtab_reset_read(struct offtab *,
                    void (*)(const char *, ...) __printflike(1,2),
                    void (*)(const char *, ...) __printflike(1,2));
bool            offtab_prepare_get(struct offtab *, uint32_t);
uint64_t        offtab_get(struct offtab *, uint32_t);

void            offtab_reset_write(struct offtab *);
void            offtab_checkpoint(struct offtab *, uint32_t, int);
#define OFFTAB_CHECKPOINT_SYNC  1
void            offtab_prepare_put(struct offtab *, uint32_t);
void            offtab_put(struct offtab *, uint32_t, uint64_t);

#endif  /* VNDCOMPRESS_OFFTAB_H */