sot/source/sdstor/stgstrms.hxx

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  30
  31 #ifndef _STGSTRMS_HXX
  32 #define _STGSTRMS_HXX
  33
  34 #ifndef _TOOLS_STREAM_HXX
  35 #include <tools/stream.hxx>
  36 #endif
  37
  38 class StgIo;
  39 class StgStrm;
  40 class StgPage;
  41 class StgDirEntry;
  42
  43 // The FAT class performs FAT operations on an underlying storage stream.
  44 // This stream is either the physical FAT stream (bPhys == TRUE ) or a normal
  45 // storage stream, which then holds the FAT for small data allocations.
  46
  47 class StgFAT
  48 {                                                                               // FAT allocator
  49     StgStrm& rStrm;                                             // underlying stream
  50     INT32 nMaxPage;                                             // highest page allocated so far
  51     short nPageSize;                                    // physical page size
  52     short nEntries;                                             // FAT entries per page
  53     short nOffset;                                              // current offset within page
  54     INT32 nLimit;                                               // search limit recommendation
  55     BOOL  bPhys;                                                // TRUE: physical FAT
  56     StgPage* GetPhysPage( INT32 nPage );
  57     BOOL  MakeChain( INT32 nStart, INT32 nPages );
  58     BOOL  InitNew( INT32 nPage1 );
  59 public:
  60     StgFAT( StgStrm& rStrm, BOOL bMark );
  61     INT32 FindBlock( INT32& nPages );
  62     INT32 GetNextPage( INT32 nPg );
  63     INT32 AllocPages( INT32 nStart, INT32 nPages );
  64     BOOL  FreePages( INT32 nStart, BOOL bAll );
  65     INT32 GetMaxPage() { return nMaxPage; }
  66     void  SetLimit( INT32 n ) { nLimit = n; }
  67 };
  68
  69 // The base stream class provides basic functionality for seeking
  70 // and accessing the data on a physical basis. It uses the built-in
  71 // FAT class for the page allocations.
  72
  73 class StgStrm {                                                 // base class for all streams
  74 protected:
  75     StgIo& rIo;                                                 // I/O system
  76     StgFAT* pFat;                                               // FAT stream for allocations
  77     StgDirEntry* pEntry;                                // dir entry (for ownership)
  78     INT32 nStart;                                               // 1st data page
  79     INT32 nSize;                                                // stream size in bytes
  80     INT32 nPos;                                                 // current byte position
  81     INT32 nPage;                                                // current logical page
  82     short nOffset;                                              // offset into current page
  83     short nPageSize;                                    // logical page size
  84     BOOL  Copy( INT32 nFrom, INT32 nBytes );
  85     StgStrm( StgIo& );
  86 public:
  87     virtual ~StgStrm();
  88     StgIo&  GetIo()             { return rIo;    }
  89     INT32   GetPos()    { return nPos;   }
  90     INT32       GetStart()      { return nStart; }
  91     INT32       GetSize()       { return nSize;  }
  92     INT32   GetPage()   { return nPage;  }
  93     short   GetPageSize() { return nPageSize; }
  94     INT32       GetPages();
  95     short       GetOffset()     { return nOffset;}
  96     void    SetEntry( StgDirEntry& );
  97     virtual BOOL SetSize( INT32 );
  98     virtual BOOL Pos2Page( INT32 nBytePos );
  99     virtual INT32 Read( void*, INT32 )            { return 0; }
 100     virtual INT32 Write( const void*, INT32 ) { return 0; }
 101     virtual StgPage* GetPhysPage( INT32 nBytePos, BOOL bForce = FALSE );
 102     virtual BOOL IsSmallStrm() { return FALSE; }
 103 };
 104
 105 // The FAT stream class provides physical access to the master FAT.
 106 // Since this access is implemented as a StgStrm, we can use the
 107 // FAT allocator.
 108
 109 class StgFATStrm : public StgStrm {             // the master FAT stream
 110     virtual BOOL Pos2Page( INT32 nBytePos );
 111     BOOL  SetPage( short, INT32 );
 112 public:
 113     StgFATStrm( StgIo& );
 114     virtual ~StgFATStrm() {}
 115     using StgStrm::GetPage;
 116     INT32 GetPage( short, BOOL, USHORT *pnMasterAlloc = 0);
 117     virtual BOOL SetSize( INT32 );
 118     virtual StgPage* GetPhysPage( INT32 nBytePos, BOOL bForce = FALSE );
 119 };
 120
 121 // The stream has a size increment which normally is 1, but which can be
 122 // set to any value is you want the size to be incremented by certain values.
 123
 124 class StgDataStrm : public StgStrm              // a physical data stream
 125 {
 126     short nIncr;                                                // size adjust increment
 127     void Init( INT32 nBgn, INT32 nLen );
 128 public:
 129     StgDataStrm( StgIo&, INT32 nBgn, INT32 nLen=-1 );
 130     StgDataStrm( StgIo&, StgDirEntry* );
 131     void* GetPtr( INT32 nPos, BOOL bForce, BOOL bDirty );
 132     void SetIncrement( short n ) { nIncr = n ; }
 133     virtual BOOL SetSize( INT32 );
 134     virtual INT32 Read( void*, INT32 );
 135     virtual INT32 Write( const void*, INT32 );
 136 };
 137
 138 // The small stream class provides access to streams with a size < 4096 bytes.
 139 // This stream is a StgStream containing small pages. The FAT for this stream
 140 // is also a StgStream. The start of the FAT is in the header at DataRootPage,
 141 // the stream itself is pointed to by the root entry (it holds start & size).
 142
 143 class StgSmallStrm : public StgStrm             // a logical data stream
 144 {
 145     StgStrm* pData;                                             // the data stream
 146     void Init( INT32 nBgn, INT32 nLen );
 147 public:
 148     StgSmallStrm( StgIo&, INT32 nBgn, INT32 nLen );
 149     StgSmallStrm( StgIo&, StgDirEntry* );
 150     virtual INT32 Read( void*, INT32 );
 151     virtual INT32 Write( const void*, INT32 );
 152     virtual BOOL IsSmallStrm() { return TRUE; }
 153 };
 154
 155 class StgTmpStrm : public SvMemoryStream
 156 {
 157     String aName;
 158     SvFileStream* pStrm;
 159     using SvMemoryStream::GetData;
 160     virtual ULONG GetData( void* pData, ULONG nSize );
 161     virtual ULONG PutData( const void* pData, ULONG nSize );
 162     virtual ULONG SeekPos( ULONG nPos );
 163     virtual void FlushData();
 164
 165 public:
 166     StgTmpStrm( ULONG=16 );
 167    ~StgTmpStrm();
 168     BOOL Copy( StgTmpStrm& );
 169     void SetSize( ULONG );
 170     using SvMemoryStream::GetSize;
 171     ULONG GetSize();
 172 };
 173
 174 #endif