Source code of Windows XP (NT5)
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149 lines
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/*++
Copyright (c) 1992-2000 Microsoft Corporation
Module Name:
rwcache.hxx
Abstract:
This class implements a read write cache.
Author:
Norbert Kusters (norbertk) 23-Apr-92
--*/
#if !defined(_READ_WRITE_CACHE_DEFN_)
#define _READ_WRITE_CACHE_DEFN_
#include "dcache.hxx"
#include "hmem.hxx"
#include "numset.hxx"
#if defined ( _AUTOCHECK_ )
#define IFSUTIL_EXPORT
#elif defined ( _IFSUTIL_MEMBER_ )
#define IFSUTIL_EXPORT __declspec(dllexport)
#else
#define IFSUTIL_EXPORT __declspec(dllimport)
#endif
//#define RWCACHE_PERF_COUNTERS 1
struct RW_CACHE_BLOCK {
BOOLEAN InUse;
BOOLEAN IsDirty;
ULONG Age;
BIG_INT SectorNumber;
HMEM SectorBuffer;
};
DEFINE_POINTER_TYPES(RW_CACHE_BLOCK);
DECLARE_CLASS(READ_WRITE_CACHE);
class READ_WRITE_CACHE : public DRIVE_CACHE {
public:
IFSUTIL_EXPORT
DECLARE_CONSTRUCTOR( READ_WRITE_CACHE );
VIRTUAL
~READ_WRITE_CACHE(
);
NONVIRTUAL
IFSUTIL_EXPORT
BOOLEAN
Initialize(
IN OUT PIO_DP_DRIVE Drive,
IN ULONG NumberOfCacheBlocks
);
VIRTUAL
BOOLEAN
Read(
IN BIG_INT StartingSector,
IN SECTORCOUNT NumberOfSectors,
OUT PVOID Buffer
);
VIRTUAL
BOOLEAN
Write(
IN BIG_INT StartingSector,
IN SECTORCOUNT NumberOfSectors,
IN PVOID Buffer
);
VIRTUAL
BOOLEAN
Flush(
);
#if defined(RWCACHE_PERF_COUNTERS)
NONVIRTUAL
IFSUTIL_EXPORT
VOID
QueryPerformanceCounters(
PULONG RMiss,
PULONG RHit,
PULONG ROverHead,
PULONG WMiss,
PULONG WHit,
PULONG Usage
);
#endif
private:
NONVIRTUAL
PRW_CACHE_BLOCK
GetSectorCacheBlock(
IN BIG_INT SectorNumber
);
NONVIRTUAL
PRW_CACHE_BLOCK
GetNextAvailbleCacheBlock(
IN BIG_INT SectorNumber
);
NONVIRTUAL
VOID
FlushThisCacheBlock(
IN OUT PRW_CACHE_BLOCK Block
);
NONVIRTUAL
VOID
Construct(
);
NONVIRTUAL
VOID
Destroy(
);
NUMBER_SET _sectors_cached;
PRW_CACHE_BLOCK* _cache_blocks;
ULONG _num_blocks;
HMEM _write_buffer;
ULONG _sector_size;
BOOLEAN _error_occurred;
ULONG _sectors_per_buffer;
#if defined(RWCACHE_PERF_COUNTERS)
ULONG _RMiss, _RHit, _ROverHead, _WMiss, _WHit, _Usage;
#endif
};
#endif