[apple/xnu.git] / bsd / hfs / hfs_endian.h

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
#ifndef __HFS_ENDIAN_H__
#define __HFS_ENDIAN_H__

#include <sys/appleapiopts.h>

#ifdef KERNEL
#ifdef __APPLE_API_PRIVATE
/*
 * hfs_endian.h
 *
 * This file prototypes endian swapping routines for the HFS/HFS Plus
 * volume format.
 */
#include "hfs.h"
#include "hfscommon/headers/BTreesInternal.h"
#include <architecture/byte_order.h>

/*********************/
/* BIG ENDIAN Macros */
/*********************/
#if BYTE_ORDER == BIG_ENDIAN

    /* HFS is always big endian, make swaps into no-ops */
    #define SWAP_BE16(__a) (__a)
    #define SWAP_BE32(__a) (__a)
    #define SWAP_BE64(__a) (__a)
    
    /* HFS is always big endian, no swapping needed */
    #define SWAP_HFS_PLUS_FORK_DATA(__a)

/************************/
/* LITTLE ENDIAN Macros */
/************************/
#elif BYTE_ORDER == LITTLE_ENDIAN

    /* HFS is always big endian, make swaps actually swap */
    #define SWAP_BE16(__a) 							NXSwapBigShortToHost (__a)
    #define SWAP_BE32(__a) 							NXSwapBigLongToHost (__a)
    #define SWAP_BE64(__a) 							NXSwapBigLongLongToHost (__a)
    
    #define SWAP_HFS_PLUS_FORK_DATA(__a)			hfs_swap_HFSPlusForkData ((__a))

#else
#warning Unknown byte order
#error
#endif

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Constants for the "unswap" argument to hfs_swap_BTNode:
 */
enum HFSBTSwapDirection {
	kSwapBTNodeBigToHost		=	0,
	kSwapBTNodeHostToBig		=	1,

	/*
	 * kSwapBTNodeHeaderRecordOnly is used to swap just the header record
	 * of a header node from big endian (on disk) to host endian (in memory).
	 * It does not swap the node descriptor (forward/backward links, record
	 * count, etc.).  It assumes the header record is at offset 0x000E.
	 *
	 * Since HFS Plus doesn't have fixed B-tree node sizes, we have to read
	 * the header record to determine the actual node size for that tree
	 * before we can set up the B-tree control block.  We read it initially
	 * as 512 bytes, then re-read it once we know the correct node size.  Since
	 * we may not have read the entire header node the first time, we can't
	 * swap the record offsets, other records, or do most sanity checks.
	 */
	kSwapBTNodeHeaderRecordOnly	=	3
};

int  hfs_swap_BTNode (BlockDescriptor *src, vnode_t vp, enum HFSBTSwapDirection direction);

#ifdef __cplusplus
}
#endif

#endif /* __APPLE_API_PRIVATE */
#endif /* KERNEL */
#endif /* __HFS_FORMAT__ */
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
37839358 A	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.
1c79356b	11	*
37839358 A	12	* This Original Code and all software distributed under the License are
37839358 A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
37839358 A	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.
1c79356b A	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22	#ifndef __HFS_ENDIAN_H__
	23	#define __HFS_ENDIAN_H__
	24
9bccf70c A	25	#include <sys/appleapiopts.h>
	26
	27	#ifdef KERNEL
	28	#ifdef __APPLE_API_PRIVATE
1c79356b A	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)
1c79356b 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))
1c79356b A	63
	64	#else
	65	#warning Unknown byte order
	66	#error
	67	#endif
	68
	69	#ifdef __cplusplus
	70	extern "C" {
	71	#endif
	72
3a60a9f5 A	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);
1c79356b A	97
	98	#ifdef __cplusplus
	99	}
	100	#endif
	101
9bccf70c A	102	#endif /* __APPLE_API_PRIVATE */
9bccf70c A	103	#endif /* KERNEL */
1c79356b	104	#endif /* __HFS_FORMAT__ */