bsd/hfs/hfs_endian.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 #ifndef __HFS_ENDIAN_H__
  23 #define __HFS_ENDIAN_H__
  24
  25 #include <sys/appleapiopts.h>
  26
  27 #ifdef KERNEL
  28 #ifdef __APPLE_API_PRIVATE
  29 /*
  30  * hfs_endian.h
  31  *
  32  * This file prototypes endian swapping routines for the HFS/HFS Plus
  33  * volume format.
  34  */
  35 #include "hfs.h"
  36 #include "hfscommon/headers/BTreesInternal.h"
  37 #include <architecture/byte_order.h>
  38
  39 /*********************/
  40 /* BIG ENDIAN Macros */
  41 /*********************/
  42 #if BYTE_ORDER == BIG_ENDIAN
  43
  44     /* HFS is always big endian, make swaps into no-ops */
  45     #define SWAP_BE16(__a) (__a)
  46     #define SWAP_BE32(__a) (__a)
  47     #define SWAP_BE64(__a) (__a)
  48
  49     /* HFS is always big endian, no swapping needed */
  50     #define SWAP_HFS_PLUS_FORK_DATA(__a)
  51
  52 /************************/
  53 /* LITTLE ENDIAN Macros */
  54 /************************/
  55 #elif BYTE_ORDER == LITTLE_ENDIAN
  56
  57     /* HFS is always big endian, make swaps actually swap */
  58     #define SWAP_BE16(__a)                                                      NXSwapBigShortToHost (__a)
  59     #define SWAP_BE32(__a)                                                      NXSwapBigLongToHost (__a)
  60     #define SWAP_BE64(__a)                                                      NXSwapBigLongLongToHost (__a)
  61
  62     #define SWAP_HFS_PLUS_FORK_DATA(__a)                        hfs_swap_HFSPlusForkData ((__a))
  63
  64 #else
  65 #warning Unknown byte order
  66 #error
  67 #endif
  68
  69 #ifdef __cplusplus
  70 extern "C" {
  71 #endif
  72
  73 /*
  74  * Constants for the "unswap" argument to hfs_swap_BTNode:
  75  */
  76 enum HFSBTSwapDirection {
  77         kSwapBTNodeBigToHost            =       0,
  78         kSwapBTNodeHostToBig            =       1,
  79
  80         /*
  81          * kSwapBTNodeHeaderRecordOnly is used to swap just the header record
  82          * of a header node from big endian (on disk) to host endian (in memory).
  83          * It does not swap the node descriptor (forward/backward links, record
  84          * count, etc.).  It assumes the header record is at offset 0x000E.
  85          *
  86          * Since HFS Plus doesn't have fixed B-tree node sizes, we have to read
  87          * the header record to determine the actual node size for that tree
  88          * before we can set up the B-tree control block.  We read it initially
  89          * as 512 bytes, then re-read it once we know the correct node size.  Since
  90          * we may not have read the entire header node the first time, we can't
  91          * swap the record offsets, other records, or do most sanity checks.
  92          */
  93         kSwapBTNodeHeaderRecordOnly     =       3
  94 };
  95
  96 int  hfs_swap_BTNode (BlockDescriptor *src, vnode_t vp, enum HFSBTSwapDirection direction);
  97
  98 #ifdef __cplusplus
  99 }
 100 #endif
 101
 102 #endif /* __APPLE_API_PRIVATE */
 103 #endif /* KERNEL */
 104 #endif /* __HFS_FORMAT__ */