fs/zfs/zfs_lzjb.c

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7 /*
   8  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
   9  * Use is subject to license terms.
  10  */
  11
  12 #include <common.h>
  13 #include <malloc.h>
  14 #include <linux/stat.h>
  15 #include <linux/time.h>
  16 #include <linux/ctype.h>
  17 #include <asm/byteorder.h>
  18 #include "zfs_common.h"
  19
  20 #include <zfs/zfs.h>
  21 #include <zfs/zio.h>
  22 #include <zfs/dnode.h>
  23 #include <zfs/uberblock_impl.h>
  24 #include <zfs/vdev_impl.h>
  25 #include <zfs/zio_checksum.h>
  26 #include <zfs/zap_impl.h>
  27 #include <zfs/zap_leaf.h>
  28 #include <zfs/zfs_znode.h>
  29 #include <zfs/dmu.h>
  30 #include <zfs/dmu_objset.h>
  31 #include <zfs/dsl_dir.h>
  32 #include <zfs/dsl_dataset.h>
  33
  34 #define MATCH_BITS      6
  35 #define MATCH_MIN       3
  36 #define OFFSET_MASK     ((1 << (16 - MATCH_BITS)) - 1)
  37
  38 /*
  39  * Decompression Entry - lzjb
  40  */
  41 #ifndef NBBY
  42 #define NBBY    8
  43 #endif
  44
  45 int
  46 lzjb_decompress(void *s_start, void *d_start, uint32_t s_len,
  47                                 uint32_t d_len)
  48 {
  49         uint8_t *src = s_start;
  50         uint8_t *dst = d_start;
  51         uint8_t *d_end = (uint8_t *) d_start + d_len;
  52         uint8_t *s_end = (uint8_t *) s_start + s_len;
  53         uint8_t *cpy, copymap = 0;
  54         int copymask = 1 << (NBBY - 1);
  55
  56         while (dst < d_end && src < s_end) {
  57                 if ((copymask <<= 1) == (1 << NBBY)) {
  58                         copymask = 1;
  59                         copymap = *src++;
  60                 }
  61                 if (src >= s_end) {
  62                         printf("lzjb decompression failed\n");
  63                         return ZFS_ERR_BAD_FS;
  64                 }
  65                 if (copymap & copymask) {
  66                         int mlen = (src[0] >> (NBBY - MATCH_BITS)) + MATCH_MIN;
  67                         int offset = ((src[0] << NBBY) | src[1]) & OFFSET_MASK;
  68                         src += 2;
  69                         cpy = dst - offset;
  70                         if (src > s_end || cpy < (uint8_t *) d_start) {
  71                                 printf("lzjb decompression failed\n");
  72                                 return ZFS_ERR_BAD_FS;
  73                         }
  74                         while (--mlen >= 0 && dst < d_end)
  75                                 *dst++ = *cpy++;
  76                 } else {
  77                         *dst++ = *src++;
  78                 }
  79         }
  80         if (dst < d_end) {
  81                 printf("lzjb decompression failed\n");
  82                 return ZFS_ERR_BAD_FS;
  83         }
  84         return ZFS_ERR_NONE;
  85 }