fsck_hfs/dfalib/hfs_endian.h

   1 /*
   2  * Copyright (c) 2000, 2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 #ifndef __HFS_ENDIAN_H__
  24 #define __HFS_ENDIAN_H__
  25
  26 /*
  27  * hfs_endian.h
  28  *
  29  * This file prototypes endian swapping routines for the HFS/HFS Plus
  30  * volume format.
  31  */
  32 #include <hfs/hfs_format.h>
  33 #include <libkern/OSByteOrder.h>
  34 #include "SRuntime.h"
  35
  36 /*********************/
  37 /* BIG ENDIAN Macros */
  38 /*********************/
  39 #define SWAP_BE16(__a)                                                  OSSwapBigToHostInt16 (__a)
  40 #define SWAP_BE32(__a)                                                  OSSwapBigToHostInt32 (__a)
  41 #define SWAP_BE64(__a)                                                  OSSwapBigToHostInt64 (__a)
  42
  43 #if BYTE_ORDER == BIG_ENDIAN
  44
  45     /* HFS is always big endian, no swapping needed */
  46     #define SWAP_HFSMDB(__a)
  47     #define SWAP_HFSPLUSVH(__a)
  48
  49 /************************/
  50 /* LITTLE ENDIAN Macros */
  51 /************************/
  52 #elif BYTE_ORDER == LITTLE_ENDIAN
  53
  54     #define SWAP_HFSMDB(__a)                            hfs_swap_HFSMasterDirectoryBlock ((__a))
  55     #define SWAP_HFSPLUSVH(__a)                         hfs_swap_HFSPlusVolumeHeader ((__a))
  56
  57 #else
  58 #warning Unknown byte order
  59 #error
  60 #endif
  61
  62 #ifdef __cplusplus
  63 extern "C" {
  64 #endif
  65
  66 /*
  67  * Constants for the "unswap" argument to hfs_swap_BTNode:
  68  */
  69 enum HFSBTSwapDirection {
  70         kSwapBTNodeBigToHost            =       0,
  71         kSwapBTNodeHostToBig            =       1,
  72
  73         /*
  74          * kSwapBTNodeHeaderRecordOnly is used to swap just the header record
  75          * of a header node from big endian (on disk) to host endian (in memory).
  76          * It does not swap the node descriptor (forward/backward links, record
  77          * count, etc.).  It assumes the header record is at offset 0x000E.
  78          *
  79          * Since HFS Plus doesn't have fixed B-tree node sizes, we have to read
  80          * the header record to determine the actual node size for that tree
  81          * before we can set up the B-tree control block.  We read it initially
  82          * as 512 bytes, then re-read it once we know the correct node size.  Since
  83          * we may not have read the entire header node the first time, we can't
  84          * swap the record offsets, other records, or do most sanity checks.
  85          */
  86         kSwapBTNodeHeaderRecordOnly     =       3
  87 };
  88
  89 void hfs_swap_HFSMasterDirectoryBlock (void *buf);
  90 void hfs_swap_HFSPlusVolumeHeader (void *buf);
  91 int  hfs_swap_BTNode (BlockDescriptor *src, SFCB *fcb, enum HFSBTSwapDirection direction);
  92
  93 #ifdef __cplusplus
  94 }
  95 #endif
  96
  97 #endif /* __HFS_FORMAT__ */