/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include "fsys_zfs.h"

#define MATCH_BITS      6
#define MATCH_MIN       3
#define OFFSET_MASK     ((1 << (16 - MATCH_BITS)) - 1)


/*ARGSUSED*/
int
lzjb_decompress(void *s_start, void *d_start, size_t s_len, size_t d_len)
{
        uchar_t *src = s_start;
        uchar_t *dst = d_start;
        uchar_t *d_end = (uchar_t *)d_start + d_len;
        uchar_t *cpy, copymap;
        int copymask = 1 << (NBBY - 1);

        while (dst < d_end) {
                if ((copymask <<= 1) == (1 << NBBY)) {
                        copymask = 1;
                        copymap = *src++;
                }
                if (copymap & copymask) {
                        int mlen = (src[0] >> (NBBY - MATCH_BITS)) + MATCH_MIN;
                        int offset = ((src[0] << NBBY) | src[1]) & OFFSET_MASK;
                        src += 2;
                        if ((cpy = dst - offset) < (uchar_t *)d_start)
                                return (-1);
                        while (--mlen >= 0 && dst < d_end)
                                *dst++ = *cpy++;
                } else {
                        *dst++ = *src++;
                }
        }
        return (0);
}