179 lines
3 KiB
C++
179 lines
3 KiB
C++
/*++
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Copyright (c) 1990 Microsoft Corporation
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Module Name:
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cluster.hxx
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Abstract:
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This class models a chain of clusters in a FAT file system. It gives
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the ability to refer to a scattered chain of clusters as one contiguous
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region of memory. This memory will be acquired from a MEM object at
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initialization.
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Author:
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Norbert P. Kusters (norbertk) 27-Nov-90
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--*/
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#if !defined(CLUSTER_CHAIN_DEFN)
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#define CLUSTER_CHAIN_DEFN
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#include "secrun.hxx"
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#include "hmem.hxx"
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#if defined ( _AUTOCHECK_ )
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#define UFAT_EXPORT
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#elif defined ( _UFAT_MEMBER_ )
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#define UFAT_EXPORT __declspec(dllexport)
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#else
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#define UFAT_EXPORT __declspec(dllimport)
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#endif
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//
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// Forward references
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//
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DECLARE_CLASS( CLUSTER_CHAIN );
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DECLARE_CLASS( FAT );
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DECLARE_CLASS( FAT_SA );
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DECLARE_CLASS( LOG_IO_DP_DRIVE );
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DECLARE_CLASS( MEM );
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class CLUSTER_CHAIN : public OBJECT {
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public:
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UFAT_EXPORT
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DECLARE_CONSTRUCTOR( CLUSTER_CHAIN );
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VIRTUAL
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UFAT_EXPORT
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~CLUSTER_CHAIN(
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);
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NONVIRTUAL
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UFAT_EXPORT
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BOOLEAN
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Initialize(
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IN OUT PMEM Mem,
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IN OUT PLOG_IO_DP_DRIVE Drive,
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IN PFAT_SA FatSuperArea,
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IN PCFAT Fat,
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IN ULONG ClusterNumber,
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IN ULONG LengthOfChain DEFAULT 0
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);
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VIRTUAL
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UFAT_EXPORT
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BOOLEAN
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Read(
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);
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VIRTUAL
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UFAT_EXPORT
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BOOLEAN
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Write(
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);
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NONVIRTUAL
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PVOID
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GetBuf(
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);
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NONVIRTUAL
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ULONG
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QueryLength(
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) CONST;
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private:
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NONVIRTUAL
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VOID
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Construct (
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);
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NONVIRTUAL
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VOID
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Destroy(
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);
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PSECRUN* _secruns;
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USHORT _num_secruns;
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ULONG _length_of_chain;
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//
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// Stuff needed for compressed volumes.
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//
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BOOLEAN _is_compressed;
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PSECRUN _secrun;
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PUCHAR _buf;
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HMEM _hmem;
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PFAT_SA _fat_sa;
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PCFAT _fat;
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PLOG_IO_DP_DRIVE
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_drive;
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ULONG _starting_cluster;
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};
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INLINE
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PVOID
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CLUSTER_CHAIN::GetBuf(
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)
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/*++
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Routine Description:
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This routine returns a pointer to the beginning of the memory map for
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the cluster chain.
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Arguments:
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None.
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Return Value:
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A pointer to the beginning of the memory map for the cluster chain.
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--*/
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{
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if (_is_compressed) {
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return _buf;
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}
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return (_secruns && _secruns[0]) ? _secruns[0]->GetBuf() : NULL;
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}
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INLINE
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ULONG
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CLUSTER_CHAIN::QueryLength(
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) CONST
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/*++
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Routine Description:
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Computes the number of clusters in the cluster chain.
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Arguments:
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None.
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Return Value:
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The number of clusters in the cluster chain.
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--*/
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{
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return _length_of_chain;
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}
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#endif // CLUSTER_CHAIN_DEFN
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