livefiles_hfs_plugin/lf_hfs_endian.h

   1 /*  Copyright © 2017-2018 Apple Inc. All rights reserved.
   2  *
   3  *  lf_hfs_endian.h
   4  *  livefiles_hfs
   5  *
   6  *  Created by Or Haimovich on 18/3/18.
   7  */
   8
   9 #ifndef lf_hfs_endian_h
  10 #define lf_hfs_endian_h
  11
  12 #include <stdio.h>
  13 #include "lf_hfs_btrees_internal.h"
  14
  15
  16 /*********************/
  17 /* BIG ENDIAN Macros */
  18 /*********************/
  19 #define SWAP_BE16(__a)                             OSSwapBigToHostInt16 (__a)
  20 #define SWAP_BE32(__a)                             OSSwapBigToHostInt32 (__a)
  21 #define SWAP_BE64(__a)                             OSSwapBigToHostInt64 (__a)
  22
  23
  24 /*
  25  * Constants for the "unswap" argument to hfs_swap_BTNode:
  26  */
  27 enum HFSBTSwapDirection {
  28     kSwapBTNodeBigToHost        =    0,
  29     kSwapBTNodeHostToBig        =    1,
  30
  31     /*
  32      * kSwapBTNodeHeaderRecordOnly is used to swap just the header record
  33      * of a header node from big endian (on disk) to host endian (in memory).
  34      * It does not swap the node descriptor (forward/backward links, record
  35      * count, etc.).  It assumes the header record is at offset 0x000E.
  36      *
  37      * Since HFS Plus doesn't have fixed B-tree node sizes, we have to read
  38      * the header record to determine the actual node size for that tree
  39      * before we can set up the B-tree control block.  We read it initially
  40      * as 512 bytes, then re-read it once we know the correct node size.  Since
  41      * we may not have read the entire header node the first time, we can't
  42      * swap the record offsets, other records, or do most sanity checks.
  43      */
  44     kSwapBTNodeHeaderRecordOnly    =    3
  45 };
  46
  47 int  hfs_swap_BTNode (BlockDescriptor *src, vnode_t vp, enum HFSBTSwapDirection direction, u_int8_t allow_empty_node);
  48
  49
  50 #endif /* lf_hfs_endian_h */