zfs_lzjb.c revision 1b8adde7ba7d5e04395c141c5400dc2cffd7d809
/*
* 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.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#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);
}