windows-nt/Source/XPSP1/NT/base/fs/utils/ufat/inc/eaheader.hxx
2020-09-26 16:20:57 +08:00

230 lines
3.9 KiB
C++

/*++
Copyright (c) 1990 Microsoft Corporation
Module Name:
eaheader.hxx
Abstract:
This class models the header and tables of the EA file.
Author:
Norbert P. Kusters (norbertk) 28-Nov-90
Notes:
Luckily all the structures are well aligned.
--*/
#if !defined(EA_HEADER_DEFN)
#define EA_HEADER_DEFN
#include "cluster.hxx"
#if defined ( _AUTOCHECK_ )
#define UFAT_EXPORT
#elif defined ( _UFAT_MEMBER_ )
#define UFAT_EXPORT __declspec(dllexport)
#else
#define UFAT_EXPORT __declspec(dllimport)
#endif
//
// Forward references
//
DECLARE_CLASS( EA_HEADER );
DECLARE_CLASS( FAT );
DECLARE_CLASS( FAT_SA );
DECLARE_CLASS( LOG_IO_DP_DRIVE );
DECLARE_CLASS( MEM );
struct _EA_FILE_HEADER {
USHORT Signature;
USHORT FormatType;
USHORT LogType;
USHORT Cluster1;
USHORT NewCValue1;
USHORT Cluster2;
USHORT NewCValue2;
USHORT Cluster3;
USHORT NewCValue3;
USHORT Handle;
USHORT NewHOffset;
UCHAR Reserved[10];
};
DEFINE_TYPE( struct _EA_FILE_HEADER, EA_FILE_HEADER );
CONST BaseTableSize = 240;
struct _EA_MAP_TBL {
USHORT BaseTab[BaseTableSize];
USHORT OffTab[1];
};
DEFINE_TYPE( struct _EA_MAP_TBL, EA_MAP_TBL );
struct _EA_HEADER_AND_TABLE {
EA_FILE_HEADER Header;
EA_MAP_TBL Table;
};
DEFINE_TYPE( struct _EA_HEADER_AND_TABLE, EA_HEADER_AND_TABLE );
CONST USHORT HeaderSignature = 0x4445;
CONST USHORT CurrentFormatType = 0;
CONST USHORT CurrentLogType = 0;
CONST USHORT Bit15 = 0x8000;
CONST USHORT InvalidHandle = 0xFFFF;
class EA_HEADER : public CLUSTER_CHAIN {
public:
UFAT_EXPORT
DECLARE_CONSTRUCTOR( EA_HEADER );
VIRTUAL
UFAT_EXPORT
~EA_HEADER(
);
NONVIRTUAL
UFAT_EXPORT
BOOLEAN
Initialize(
IN OUT PMEM Mem,
IN OUT PLOG_IO_DP_DRIVE Drive,
IN PFAT_SA FatSuperArea,
IN PCFAT Fat,
IN ULONG StartingCluster,
IN ULONG LengthOfChain DEFAULT 0
);
NONVIRTUAL
PEA_FILE_HEADER
GetEaFileHeader(
);
NONVIRTUAL
PEA_MAP_TBL
GetMapTable(
);
NONVIRTUAL
LONG
QueryOffTabSize(
) CONST;
NONVIRTUAL
UFAT_EXPORT
USHORT
QueryEaSetClusterNumber(
IN USHORT Handle
) CONST;
private:
NONVIRTUAL
VOID
Construct(
);
NONVIRTUAL
VOID
Destroy(
);
PEA_HEADER_AND_TABLE _ht;
LONG _off_tab_size;
};
INLINE
PEA_FILE_HEADER
EA_HEADER::GetEaFileHeader(
)
/*++
Routine Description:
This routine returns a pointer to the EA file header. Dereferencing
this pointer will allow the client to examine and modify the
EA file header. These changes will take effect on disk when the
client issues a 'Write' command.
Arguments:
None.
Return Value:
A pointer to the EA file header.
--*/
{
return _ht ? &_ht->Header : NULL;
}
INLINE
PEA_MAP_TBL
EA_HEADER::GetMapTable(
)
/*++
Routine Description:
This routine returns a pointer to the EA mapping table. Dereferencing
this pointer will allow the client to examine and modify the
EA mapping table. These changes will take effect on disk when the
client issues a 'Write' command.
Arguments:
None.
Return Value:
A pointer to the EA mapping table.
--*/
{
return _ht ? &_ht->Table : NULL;
}
INLINE
LONG
EA_HEADER::QueryOffTabSize(
) CONST
/*++
Routine Description:
Computes the number of entries in the offset table.
Arguments:
None.
Return Value:
Returns the number of entries in the offset table.
--*/
{
return _off_tab_size;
}
#endif // EA_HEADER_DEFN