hfs-522.100.5.tar.gz

[apple/hfs.git] / core / hfs_endian.h

diff --git a/core/hfs_endian.h b/core/hfs_endian.h
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+/*
+ * Copyright (c) 2000, 2002-2003, 2005-2008 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ * 
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_OSREFERENCE_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 "BTreesInternal.h"
+#include <libkern/OSByteOrder.h>
+
+/*********************/
+/* BIG ENDIAN Macros */
+/*********************/
+#define SWAP_BE16(__a)                                                         OSSwapBigToHostInt16 (__a)
+#define SWAP_BE32(__a)                                                         OSSwapBigToHostInt32 (__a)
+#define SWAP_BE64(__a)                                                         OSSwapBigToHostInt64 (__a)
+
+#if BYTE_ORDER == BIG_ENDIAN
+    
+    /* HFS is always big endian, no swapping needed */
+    #define SWAP_HFS_PLUS_FORK_DATA(__a)
+
+/************************/
+/* LITTLE ENDIAN Macros */
+/************************/
+#elif BYTE_ORDER == LITTLE_ENDIAN
+
+    #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, 
+       u_int8_t allow_empty_node);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __APPLE_API_PRIVATE */
+#endif /* KERNEL */
+#endif /* __HFS_FORMAT__ */