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
63extern "C" {
64#endif
65
66/*
67 * Constants for the "unswap" argument to hfs_swap_BTNode:
68 */
69enum 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
89void hfs_swap_HFSMasterDirectoryBlock (void *buf);
90void hfs_swap_HFSPlusVolumeHeader (void *buf);
91int  hfs_swap_BTNode (BlockDescriptor *src, SFCB *fcb, enum HFSBTSwapDirection direction);
92
93#ifdef __cplusplus
94}
95#endif
96
97#endif /* __HFS_FORMAT__ */
98