1416 lines
35 KiB
C++
1416 lines
35 KiB
C++
//+-------------------------------------------------------------------------
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//
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// Microsoft Windows
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// Copyright (C) Microsoft Corporation, 1992 - 1992.
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//
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// File: fat.cxx
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//
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// Contents: Allocation functions for MStream
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//
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// Classes: None. (defined in fat.hxx)
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//
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//--------------------------------------------------------------------------
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#include "msfhead.cxx"
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#include "h/difat.hxx"
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#include "h/sstream.hxx"
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#include "mread.hxx"
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//+-------------------------------------------------------------------------
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//
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// Method: CFatSect::Init, public
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//
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// Synopsis: CFatSect initialization function
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//
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// Effects: [uEntries] -- Number of entries in sector
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//
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// Algorithm: Allocate an array of SECT with size uEntries from
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// the heap.
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//
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//--------------------------------------------------------------------------
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SCODE CFatSect::Init(FSOFFSET uEntries)
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{
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msfDebugOut((DEB_FAT,"In CFatSect constructor\n"));
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//This assumes that FREESECT is always 0xFFFFFFFF
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memset(_asectEntry, 0xFF, uEntries * sizeof(SECT));
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msfDebugOut((DEB_FAT,"Out CFatSect constructor\n"));
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return S_OK;
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}
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//+-------------------------------------------------------------------------
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//
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// Method: CFatSect::InitCopy, public
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//
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// Synopsis: Initialization function for copying FatSects
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//
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// Arguments: [fsOld] -- Reference to FatSect to be copies
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//
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// Returns: S_OK if call completed successfully.
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//
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// Algorithm: Allocate a new array of SECT and copy old
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// information in.
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//
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//--------------------------------------------------------------------------
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SCODE CFatSect::InitCopy(USHORT uSize, CFatSect& fsOld)
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{
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msfDebugOut((DEB_FAT,"In CFatSect copy constructor\n"));
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msfDebugOut((DEB_FAT,"This = %p, fsOld = %p\n",this,&fsOld));
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msfDebugOut((DEB_FAT,"Sector size is %u sectors\n",uSize));
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memcpy(_asectEntry,fsOld._asectEntry,sizeof(SECT)*uSize);
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msfDebugOut((DEB_FAT,"Out CFatSect copy constructor\n"));
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return S_OK;
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}
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//+-------------------------------------------------------------------------
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//
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// Method: CFat::CFat, public
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//
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// Synopsis: CFat constructor.
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//
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// Arguments: [pmsParent] -- Pointer to parent multistream.
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//
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// Algorithm: Set uFatEntries to match parent MS header info.
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// Initialize all member variables.
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//
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// Notes:
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//
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//--------------------------------------------------------------------------
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CFat::CFat(SID sid, USHORT cbSector, USHORT uSectorShift)
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: _fv( sid,
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(USHORT) (cbSector >> 2), // 4 bytes per entry
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(USHORT) (cbSector >> 2) ),
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// left shift this amount for FAT
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_uFatShift((USHORT) (uSectorShift - 2) ),
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// (# entries per sector) - 1
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_uFatMask( (USHORT) ((cbSector >> 2) - 1)),
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_sid(sid),
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_pmsParent(NULL),
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_sectFirstFree( (SECT) 0),
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_sectMax(ENDOFCHAIN)
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{
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}
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//+---------------------------------------------------------------------------
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//
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// Member: CFat::Empty, public
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//
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// Synopsis: Empty all the control structures of this instance
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//
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// Arguments: None.
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//
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// Returns: void.
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//
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//----------------------------------------------------------------------------
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void CFat::Empty(void)
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{
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_fv.Empty();
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_pmsParent = NULL;
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_cfsTable = 0;
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_ulFreeSects = MAX_ULONG;
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_sectFirstFree = 0;
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_sectMax = ENDOFCHAIN;
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}
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//+-------------------------------------------------------------------------
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//
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// Method: CFat::~CFat, public
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//
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// Synopsis: CFat Destructor
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//
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// Algorithm: delete dynamically allocated storage
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//
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// Notes:
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//
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//--------------------------------------------------------------------------
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CFat::~CFat()
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{
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msfDebugOut((DEB_FAT,"In CFat destructor. Size of fat is %lu\n",_cfsTable));
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msfDebugOut((DEB_FAT,"Exiting CFat destructor\n"));
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CFat::GetFree, private
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//
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// Synposis: Locate and return a free sector in the FAT
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//
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// Effects: May modify full bit on full sectors
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//
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// Arguments: [psectRet] -- Pointer to return value
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//
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// Returns: S_OK if call completed successfully.
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//
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// Algorithm: Do a linear search of all tables until a free sector is
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// found. If all tables are full, extend the FAT by one
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// sector.
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//
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// Notes:
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//
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//---------------------------------------------------------------------------
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SCODE CFat::GetFree(ULONG ulCount, SECT *psectRet)
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{
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FSINDEX ipfs;
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FSOFFSET isect;
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SECT sectRetval;
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SCODE sc;
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SECT sectLast = ENDOFCHAIN;
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FSINDEX ipfsLast;
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FSOFFSET isectLast;
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*psectRet = ENDOFCHAIN;
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while (TRUE)
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{
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if (_ulFreeSects == MAX_ULONG)
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{
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msfChk(CountFree(&_ulFreeSects));
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}
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#if DBG == 1
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else
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{
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ULONG ulFree;
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msfChk(CountFree(&ulFree));
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msfAssert((ulFree == _ulFreeSects) &&
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aMsg("Free count doesn't match cached value."));
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}
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#endif
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while (ulCount > _ulFreeSects)
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{
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#if DBG == 1
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ULONG ulFree = _ulFreeSects;
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#endif
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msfChk(Resize(_cfsTable +
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((ulCount - _ulFreeSects + _fv.GetSectTable() - 1) >>
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_uFatShift)));
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#if DBG == 1
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msfAssert(_ulFreeSects > ulFree &&
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aMsg("Number of free sectors didn't increase after Resize."));
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#endif
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}
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FSOFFSET isectStart;
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FSINDEX ipfsStart;
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SectToPair(_sectFirstFree, &ipfsStart, &isectStart);
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for (ipfs = ipfsStart; ipfs < _cfsTable; ipfs++)
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{
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CVectBits *pfb = _fv.GetBits(ipfs);
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if ((pfb == NULL) || (!pfb->full))
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{
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CFatSect *pfs;
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msfChk(_fv.GetTable(ipfs, FB_NONE, &pfs));
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if (pfb != NULL)
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{
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isectStart = pfb->firstfree;
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}
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for (isect = isectStart; isect < _fv.GetSectTable(); isect++)
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{
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SECT sectCurrent = pfs->GetSect(isect);
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SECT sectNew = PairToSect(ipfs, isect);
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if (sectCurrent == FREESECT)
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{
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msfAssert(_ulFreeSects != MAX_ULONG &&
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aMsg("Free sect count not set"));
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_ulFreeSects--;
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sectRetval = sectNew;
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if (pfb != NULL)
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{
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olAssert(isect+1 < USHRT_MAX);
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pfb->firstfree = (USHORT) (isect + 1);
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}
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msfAssert(sectRetval >= _sectFirstFree &&
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aMsg("Found free sector before _sectFirstFree"));
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_sectFirstFree = sectRetval + 1;
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pfs->SetSect(isect, ENDOFCHAIN);
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msfChkTo(Err_Rel, _fv.SetDirty(ipfs));
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if (sectLast != ENDOFCHAIN)
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{
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if (ipfsLast == ipfs)
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{
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pfs->SetSect(isectLast, sectRetval);
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}
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else
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{
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CFatSect *pfsLast;
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msfChkTo(Err_Rel, _fv.GetTable(
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ipfsLast,
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FB_DIRTY,
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&pfsLast));
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pfsLast->SetSect(isectLast, sectRetval);
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_fv.ReleaseTable(ipfsLast);
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}
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}
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if (*psectRet == ENDOFCHAIN)
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{
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*psectRet = sectRetval;
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}
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ulCount--;
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if (ulCount == 0)
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{
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_fv.ReleaseTable(ipfs);
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if (sectRetval >= _sectMax)
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{
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_sectMax = sectRetval + 1;
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}
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return S_OK;
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}
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else
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{
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sectLast = sectRetval;
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ipfsLast = ipfs;
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isectLast = isect;
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}
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}
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}
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_fv.ReleaseTable(ipfs);
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if (pfb != NULL)
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{
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pfb->full = TRUE;
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}
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}
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isectStart = 0;
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}
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if (sectRetval >= _sectMax)
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{
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_sectMax = sectRetval + 1;
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}
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}
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msfAssert(0 &&
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aMsg("GetFree exited improperly."));
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sc = STG_E_ABNORMALAPIEXIT;
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Err:
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return sc;
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Err_Rel:
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_fv.ReleaseTable(ipfs);
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return sc;
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CFat::GetLength, public
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//
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// Synposis: Return the length of a fat chain.
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//
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// Arguments: [sect] -- Sector to begin count at.
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//
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// Returns: Length of the chain, in sectors
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//
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// Algorithm: Traverse the chain until ENDOFCHAIN is reached.
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//
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// Notes:
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//
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//---------------------------------------------------------------------------
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SCODE CFat::GetLength(SECT sect, ULONG * pulRet)
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{
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msfDebugOut((DEB_FAT,"In CFat::GetLength(%lu)\n",sect));
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SCODE sc = S_OK;
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ULONG csect = 0;
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while (sect != ENDOFCHAIN)
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{
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msfChk(GetNext(sect, §));
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csect++;
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}
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msfDebugOut((DEB_FAT,"FAT: GetLength returned %u\n",csect));
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*pulRet = csect;
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Err:
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return sc;
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}
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//+-------------------------------------------------------------------------
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//
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// Member: CFat::Init, public
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//
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// Synposis: Sets up a FAT, reading data from an existing stream
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//
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// Effects: Changes all _apfsTable entries, _cfsTable, and all
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// flags fields
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//
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// Arguments: None.
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//
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// Returns: S_OK if call completed OK.
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//
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// Algorithm: Read size from first FAT in stream.
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// Resize array to necessary size.
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// Read in FAT sectors sequentially.
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//
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// Notes:
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//
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//---------------------------------------------------------------------------
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SCODE CFat::Init(CMStream *pmsParent, FSINDEX cFatSect, BOOL fConvert)
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{
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SCODE sc;
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UNREFERENCED_PARM(fConvert);
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msfDebugOut((DEB_FAT,"CFat::setup thinks the FAT is size %lu\n",cFatSect));
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_pmsParent = pmsParent;
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msfChk(_fv.Init(_pmsParent, cFatSect));
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_cfsTable = cFatSect;
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USHORT cbSectorSize;
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cbSectorSize = _pmsParent->GetSectorSize();
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_ulFreeSects = MAX_ULONG;
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Err:
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return sc;
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}
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//+-------------------------------------------------------------------------
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//
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// Method: CFat::InitConvert, public
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//
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// Synopsis: Init function used for conversion
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//
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// Arguments: [sectData] -- number of sectors used by file
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//
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// Returns: S_OK if call completed OK.
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//
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// Algorithm: *Finish This*
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//
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// Notes:
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//
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//--------------------------------------------------------------------------
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SCODE CFat::InitConvert(CMStream *pmsParent, SECT sectData)
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{
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SCODE sc;
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msfDebugOut((DEB_FAT,"Doing conversion\n"));
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_pmsParent = pmsParent;
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msfAssert((sectData != 0) &&
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aMsg("Attempt to convert zero length file."));
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SECT sectMax = 0;
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FSINDEX csectFat = 0;
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FSINDEX csectLast;
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if (_sid == SIDFAT)
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{
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SECT sectTotal;
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//Since the fat needs to represent itself, we can't determine
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// the actual number of sectors needed in one pass. We
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// therefore loop, factoring in the number of fat sectors
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// at each iteration, until we reach a stable state.
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//
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//As an example, consider the case where each fat sector represents
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// 128 sectors and the file being converted is 128 sectors long.
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// There will be no DIFat - therefore, we have 128 sectors needed
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// on the first pass, which will require 1 fat sector to
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// represent them. On the second pass, we discover that we
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// actually need 2 fat sectors, since we now have 129 total
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// sectors to allocate space for. The third pass will result
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// in a stable state.
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do
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{
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csectLast = csectFat;
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sectTotal = sectData + _pmsParent->GetHeader()->GetDifLength() +
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csectFat + 1;
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csectFat = (sectTotal + _fv.GetSectTable() - 1) >> _uFatShift;
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}
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while (csectLast != csectFat);
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sectMax = sectData + _pmsParent->GetHeader()->GetDifLength();
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}
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else
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{
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//The minifat doesn't need to represent itself, so we can
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// compute the number of sectors needed in one pass.
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sectMax = sectData;
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csectFat = (sectMax + _fv.GetSectTable() -1) >> _uFatShift;
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}
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msfChk(_fv.Init(_pmsParent, csectFat));
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FSINDEX i;
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if (_sid == SIDMINIFAT)
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{
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SECT sectFirst;
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msfChk(_pmsParent->GetFat()->Allocate(csectFat, §First));
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_pmsParent->GetHeader()->SetMiniFatStart(sectFirst);
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_pmsParent->GetHeader()->SetMiniFatLength(csectFat);
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}
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for (i = 0; i < csectFat; i++)
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{
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CFatSect *pfs;
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msfChk(_fv.GetTable(i, FB_NEW, &pfs));
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if (_sid == SIDFAT)
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{
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_fv.SetSect(i, sectMax + i);
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_pmsParent->GetDIFat()->SetFatSect(i, sectMax + i);
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}
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else
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{
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SECT sect;
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msfChk(_pmsParent->GetESect(_sid, i, §));
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_fv.SetSect(i, sect);
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}
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_fv.ReleaseTable(i);
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}
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_cfsTable = csectFat;
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if (_sid != SIDMINIFAT)
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{
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_pmsParent->GetHeader()->SetFatLength(_cfsTable);
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SECT sect;
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if (sectData > 1)
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{
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for (sect = 0; sect < sectData - 2; sect++)
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{
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msfChk(SetNext(sect, sect + 1));
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}
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msfChk(SetNext(sectData - 2, ENDOFCHAIN));
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msfChk(SetNext(sectData - 1, 0));
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}
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else
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{
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//In the event that the file to be converted is less
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// than one sector long, we don't need to create a
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// real chain, just a single terminated sector.
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msfChk(SetNext(0, ENDOFCHAIN));
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}
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for (sect = sectData; sect < sectMax; sect++)
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{
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msfChk(SetNext(sect, DIFSECT));
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}
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for (ULONG j = 0; j < csectFat; j++)
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{
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msfChk(SetNext(sectMax + j, FATSECT));
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}
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//Set up directory chain.
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msfChk(SetNext(sectMax + i, ENDOFCHAIN));
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_pmsParent->GetHeader()->SetDirStart(sectMax + i);
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_ulFreeSects = (_cfsTable << _uFatShift) - (sectMax + csectFat + 1);
|
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}
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else
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{
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for (SECT sect = 0; sect < sectData -1; sect++)
|
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{
|
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msfChk(SetNext(sect, sect + 1));
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}
|
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msfChk(SetNext(sectData - 1, ENDOFCHAIN));
|
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_ulFreeSects = (_cfsTable << _uFatShift) - sectData;
|
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}
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|
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msfChk(_pmsParent->SetSize());
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Err:
|
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return sc;
|
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}
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::InitNew, public
|
|
//
|
|
// Synposis: Sets up a FAT for a newly created multi-strean
|
|
//
|
|
// Effects: Changes all _apfsTable entries, _cfsTable, and all
|
|
// flags fields
|
|
//
|
|
// Arguments: [pmsparent] -- pointer to parent Mstream
|
|
//
|
|
// Returns: S_OK if call completed OK.
|
|
//
|
|
// Algorithm: Set parent pointer.
|
|
// Allocate 1 sector for FAT and 1 for Directory.
|
|
//
|
|
// Notes:
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
|
|
SCODE CFat::InitNew(CMStream *pmsParent)
|
|
{
|
|
msfDebugOut((DEB_FAT,"In CFat::InitNew()\n"));
|
|
SCODE sc;
|
|
|
|
_pmsParent = pmsParent;
|
|
|
|
FSINDEX count;
|
|
if (SIDMINIFAT == _sid)
|
|
count = _pmsParent->GetHeader()->GetMiniFatLength();
|
|
else
|
|
count = _pmsParent->GetHeader()->GetFatLength();
|
|
|
|
msfDebugOut((DEB_FAT,"Setting up Fat of size %lu\n",count));
|
|
|
|
msfChk(_fv.Init(_pmsParent, count));
|
|
|
|
_cfsTable = count;
|
|
|
|
if (SIDFAT == _sid)
|
|
{
|
|
FSINDEX ipfs;
|
|
FSOFFSET isect;
|
|
CFatSect *pfs;
|
|
|
|
SectToPair(_pmsParent->GetHeader()->GetFatStart(), &ipfs, &isect);
|
|
msfChk(_fv.GetTable(ipfs, FB_NEW, &pfs));
|
|
_fv.SetSect(ipfs, _pmsParent->GetHeader()->GetFatStart());
|
|
_fv.ReleaseTable(ipfs);
|
|
|
|
msfChk(SetNext(_pmsParent->GetHeader()->GetFatStart(), FATSECT));
|
|
msfDebugOut((DEB_ITRACE,"Set sector %lu (FAT) to ENDOFCHAIN\n",_pmsParent->GetHeader()->GetFatStart()));
|
|
|
|
msfChk(SetNext(_pmsParent->GetHeader()->GetDirStart(), ENDOFCHAIN));
|
|
msfDebugOut((DEB_ITRACE,"Set sector %lu (DIR) to ENDOFCHAIN\n",_pmsParent->GetHeader()->GetDirStart()));
|
|
_ulFreeSects = (count << _uFatShift) - 2;
|
|
}
|
|
else
|
|
{
|
|
_ulFreeSects = 0;
|
|
}
|
|
|
|
msfChk(_pmsParent->SetSize());
|
|
|
|
msfDebugOut((DEB_FAT,"Exiting CFat::setupnew()\n"));
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::Resize, private
|
|
//
|
|
// Synposis: Resize FAT, both in memory and in the file
|
|
//
|
|
// Effects: Modifies _cfsTable, _apfsTable, and all flags fields
|
|
//
|
|
// Arguments: [ulSize] -- New size (in # of tables) for FAT
|
|
//
|
|
// Returns: S_OK if call completed OK.
|
|
//
|
|
// Algorithm: Allocate new array of new size.
|
|
// Copy over all old pointers.
|
|
// Allocate new tables for any necessary.
|
|
//
|
|
// Notes: This routine currently cannot reduce the size of a fat
|
|
|
|
//---------------------------------------------------------------------------
|
|
|
|
SCODE CFat::Resize(ULONG ulSize)
|
|
{
|
|
msfDebugOut((DEB_FAT,"In CFat::Resize(%lu)\n",ulSize));
|
|
SCODE sc;
|
|
|
|
if (ulSize == _cfsTable)
|
|
{
|
|
return S_OK;
|
|
}
|
|
|
|
ULONG csect = _cfsTable;
|
|
|
|
msfAssert(ulSize > _cfsTable &&
|
|
aMsg("Attempted to shrink Fat"));
|
|
|
|
|
|
ULONG ipfs;
|
|
SECT sectNew;
|
|
|
|
CFat *pfat = _pmsParent->GetFat();
|
|
|
|
|
|
if (_sid == SIDFAT)
|
|
{
|
|
|
|
//Make sure we have enough space for all of the sectors
|
|
// to be allocated.
|
|
|
|
ULONG csectFat = ulSize - _cfsTable;
|
|
ULONG csectPerDif = (1 << _uFatShift) - 1;
|
|
ULONG csectDif = (csectFat + csectPerDif - 1) / csectPerDif;
|
|
|
|
|
|
//Assuming all the free sectors are at the end of the file,
|
|
// we need a file csectNew sectors long to hold them.
|
|
|
|
ULONG csectOld, csectNew;
|
|
|
|
msfChk(FindMaxSect(&csectOld));
|
|
|
|
csectNew = csectOld + csectFat + csectDif;
|
|
|
|
ULARGE_INTEGER cbSize;
|
|
|
|
ULISet32(cbSize, ConvertSectOffset(
|
|
csectNew,
|
|
0,
|
|
_pmsParent->GetSectorShift()));
|
|
|
|
msfHChk(_pmsParent->GetILB()->SetSize(cbSize));
|
|
|
|
//If we are the fat, we have enough space in the file for
|
|
// ourselves at this point.
|
|
}
|
|
else
|
|
{
|
|
if (_cfsTable == 0)
|
|
{
|
|
msfChk(pfat->Allocate(ulSize, §New));
|
|
_pmsParent->GetHeader()->SetMiniFatStart(sectNew);
|
|
}
|
|
else
|
|
{
|
|
sectNew = _pmsParent->GetHeader()->GetMiniFatStart();
|
|
|
|
SECT sectLast;
|
|
msfChk(pfat->GetESect(sectNew, ulSize - 1, §Last));
|
|
|
|
}
|
|
|
|
msfChk(_pmsParent->SetSize());
|
|
|
|
|
|
msfChk(pfat->GetSect(sectNew, csect, §New));
|
|
|
|
//If we are the Minifat, we have enough space in the underlying
|
|
// file for ourselves at this point.
|
|
}
|
|
|
|
|
|
_fv.Resize(ulSize);
|
|
|
|
|
|
for (ipfs = csect; ipfs < ulSize; ipfs++)
|
|
{
|
|
CFatSect *pfs;
|
|
msfChk(_fv.GetTable(ipfs, FB_NEW, &pfs));
|
|
_cfsTable = ipfs + 1;
|
|
_ulFreeSects += (1 << _uFatShift);
|
|
|
|
if (_sid == SIDFAT)
|
|
{
|
|
msfChk(pfat->GetFree(1, §New));
|
|
|
|
msfChk(_pmsParent->GetDIFat()->SetFatSect(ipfs, sectNew));
|
|
msfChk(pfat->SetNext(sectNew, FATSECT));
|
|
}
|
|
|
|
msfAssert(sectNew != ENDOFCHAIN &&
|
|
aMsg("Bad sector returned for fatsect."));
|
|
|
|
_fv.SetSect(ipfs, sectNew);
|
|
_fv.ReleaseTable(ipfs);
|
|
|
|
if (_sid == SIDMINIFAT)
|
|
{
|
|
msfChk(pfat->GetNext(sectNew, §New));
|
|
}
|
|
}
|
|
|
|
msfDebugOut((DEB_FAT,"CFat::Resize() - all new objects allocated\n"));
|
|
|
|
if (SIDMINIFAT == _sid)
|
|
_pmsParent->GetHeader()->SetMiniFatLength(_cfsTable);
|
|
else
|
|
_pmsParent->GetHeader()->SetFatLength(_cfsTable);
|
|
|
|
|
|
//This setsize should only shrink the file.
|
|
#if DBG == 1
|
|
STATSTG stat;
|
|
|
|
msfHChk(_pmsParent->GetILB()->Stat(&stat, STATFLAG_NONAME));
|
|
#endif
|
|
|
|
msfChk(_pmsParent->SetSize());
|
|
|
|
#if DBG == 1
|
|
STATSTG statNew;
|
|
|
|
msfHChk(_pmsParent->GetILB()->Stat(&statNew, STATFLAG_NONAME));
|
|
|
|
msfAssert(ULIGetLow(statNew.cbSize) <= ULIGetLow(stat.cbSize));
|
|
#endif
|
|
|
|
msfDebugOut((DEB_FAT,"Out CFat::Resize(%lu)\n",ulSize));
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::Extend, private
|
|
//
|
|
// Synposis: Increase the size of an existing chain
|
|
//
|
|
// Effects: Modifies ulSize sectors within the fat. Causes one or
|
|
// more sector writes.
|
|
//
|
|
// Arguments: [sect] -- Sector ID of last sector in chain to be extended
|
|
// [ulSize] -- Number of sectors to add to chain
|
|
//
|
|
// Requires: sect must be at the end of a chain.
|
|
//
|
|
// Returns: S_OK if call completed OK.
|
|
//
|
|
// Algorithm: Use calls to GetFree to allocate chain.
|
|
//
|
|
// Notes:
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
|
|
SCODE CFat::Extend(SECT sect, ULONG ulSize)
|
|
{
|
|
SCODE sc;
|
|
|
|
msfDebugOut((DEB_FAT,"In CFat::Extend(%lu,%lu)\n",sect,ulSize));
|
|
SECT sectTemp;
|
|
|
|
msfChk(GetFree(ulSize, §Temp));
|
|
msfChk(SetNext(sect, sectTemp));
|
|
|
|
msfDebugOut((DEB_FAT,"Out CFat::Extend()\n"));
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::GetNext, public
|
|
//
|
|
// Synposis: Returns the next sector in a chain, given a sector
|
|
//
|
|
// Arguments: [sect] -- Sector ID of any sector in a chain.
|
|
//
|
|
// Returns: Sector ID of next sector in chain, ENDOFCHAIN if at end
|
|
//
|
|
// Notes:
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
|
|
SCODE CFat::GetNext(const SECT sect, SECT * psRet)
|
|
{
|
|
SCODE sc;
|
|
|
|
FSINDEX ipfs;
|
|
FSOFFSET isect;
|
|
|
|
msfAssert(sect <= MAXREGSECT &&
|
|
aMsg("Called GetNext() on invalid sector"));
|
|
|
|
SectToPair(sect, &ipfs, &isect);
|
|
CFatSect *pfs;
|
|
msfChk(_fv.GetTable(ipfs, FB_NONE, &pfs));
|
|
|
|
*psRet = pfs->GetSect(isect);
|
|
|
|
_fv.ReleaseTable(ipfs);
|
|
|
|
msfAssert(sect != *psRet &&
|
|
aMsg("Detected loop in fat chain."));
|
|
return S_OK;
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::SetNext, private
|
|
//
|
|
// Synposis: Set the next sector in a chain
|
|
//
|
|
// Effects: Modifies a single entry within the fat.
|
|
//
|
|
// Arguments: [sectFirst] -- Sector ID of first sector
|
|
// [sectNext] -- Sector ID of next sector
|
|
//
|
|
// Returns: void
|
|
//
|
|
// Notes:
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
SCODE CFat::SetNext(SECT sectFirst, SECT sectNext)
|
|
{
|
|
FSINDEX ipfs;
|
|
FSOFFSET isect;
|
|
SCODE sc;
|
|
|
|
|
|
// creating infinite loops is a no-no
|
|
msfAssert(sectFirst != sectNext &&
|
|
aMsg("Attempted to create loop in Fat chain"));
|
|
msfAssert(sectFirst <= MAXREGSECT &&
|
|
aMsg("Called SetNext on invalid sector"));
|
|
|
|
SectToPair(sectFirst, &ipfs, &isect);
|
|
|
|
CFatSect *pfs;
|
|
|
|
msfChk(_fv.GetTable(ipfs, FB_DIRTY, &pfs));
|
|
|
|
pfs->SetSect(isect,sectNext);
|
|
|
|
_fv.ReleaseTable(ipfs);
|
|
|
|
if (sectNext == FREESECT)
|
|
{
|
|
CVectBits *pfb;
|
|
pfb = _fv.GetBits(ipfs);
|
|
|
|
if ((pfb != NULL) &&
|
|
((pfb->full == TRUE) || (isect < pfb->firstfree)))
|
|
{
|
|
pfb->full = FALSE;
|
|
pfb->firstfree = isect;
|
|
}
|
|
|
|
if (sectFirst == _sectMax - 1)
|
|
{
|
|
_sectMax = ENDOFCHAIN;
|
|
}
|
|
if (sectFirst < _sectFirstFree)
|
|
{
|
|
_sectFirstFree = sectFirst;
|
|
}
|
|
|
|
if (_ulFreeSects != MAX_ULONG)
|
|
{
|
|
_ulFreeSects++;
|
|
}
|
|
}
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::CountFree, private
|
|
//
|
|
// Synposis: Count and return the number of free sectors in the Fat
|
|
//
|
|
// Arguments: void.
|
|
//
|
|
// Returns: void.
|
|
//
|
|
// Algorithm: Do a linear search of the Fat, counting free sectors.
|
|
// If a FatSect has its full bit set, it is not necessary
|
|
// to search that FatSect.
|
|
//
|
|
// Notes:
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
|
|
SCODE CFat::CountFree(ULONG * pulRet)
|
|
{
|
|
msfDebugOut((DEB_FAT,"In CFat::CountFree()\n"));
|
|
SCODE sc = S_OK;
|
|
|
|
FSINDEX ipfs;
|
|
ULONG csectFree=0;
|
|
FSOFFSET isectStart;
|
|
FSINDEX ipfsStart;
|
|
|
|
SectToPair(_sectFirstFree, &ipfsStart, &isectStart);
|
|
|
|
for (ipfs = ipfsStart; ipfs < _cfsTable; ipfs++)
|
|
{
|
|
CVectBits *pfb = _fv.GetBits(ipfs);
|
|
|
|
if ((pfb == NULL) || (!pfb->full))
|
|
{
|
|
msfDebugOut((DEB_FAT,"Checking table %lu\n",ipfs));
|
|
CFatSect *pfs;
|
|
msfChk(_fv.GetTable(ipfs, FB_NONE, &pfs));
|
|
|
|
if (pfb != NULL)
|
|
{
|
|
isectStart = pfb->firstfree;
|
|
}
|
|
|
|
FSOFFSET isect;
|
|
for (isect = isectStart; isect < _fv.GetSectTable(); isect++)
|
|
{
|
|
SECT sectCurrent = pfs->GetSect(isect);
|
|
SECT sectNew = PairToSect(ipfs, isect);
|
|
|
|
|
|
|
|
if (sectCurrent == FREESECT)
|
|
{
|
|
csectFree++;
|
|
}
|
|
}
|
|
_fv.ReleaseTable(ipfs);
|
|
}
|
|
isectStart = 0;
|
|
}
|
|
msfDebugOut((DEB_FAT,"Countfree returned %lu\n",csectFree));
|
|
*pulRet = csectFree;
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::GetSect, public
|
|
//
|
|
// Synposis: Return the nth sector in a chain
|
|
//
|
|
// Arguments: [sect] -- Sector ID of beginning of chain
|
|
// [uNum] -- indicator of which sector is to be returned
|
|
// [psectReturn] -- Pointer to storage for return value
|
|
//
|
|
// Returns: S_OK.
|
|
//
|
|
// Algorithm: Linearly traverse chain until numth sector
|
|
//
|
|
// Notes:
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
|
|
SCODE CFat::GetSect(SECT sect, ULONG ulNum, SECT * psectReturn)
|
|
{
|
|
msfDebugOut((DEB_FAT,"In CFat::GetSect(%lu,%lu)\n",sect,ulNum));
|
|
|
|
SCODE sc = S_OK;
|
|
|
|
if (ulNum == 0)
|
|
{
|
|
msfDebugOut((DEB_FAT,"Out CFat::GetSect()=>%lu\n",sect));
|
|
}
|
|
else if ((SIDFAT == _sid) &&
|
|
(_pmsParent->GetHeader()->GetFatStart() == sect))
|
|
{
|
|
msfChk(_pmsParent->GetDIFat()->GetFatSect(ulNum, §));
|
|
}
|
|
else for (ULONG i = 0; i < ulNum; i++)
|
|
{
|
|
msfChk(GetNext(sect, §));
|
|
if (sect > MAXREGSECT)
|
|
{
|
|
//The stream isn't long enough, so stop.
|
|
msfAssert(sect == ENDOFCHAIN &&
|
|
aMsg("Found invalid sector in fat chain."));
|
|
break;
|
|
}
|
|
}
|
|
|
|
*psectReturn = sect;
|
|
msfDebugOut((DEB_FAT,"Out CFat::GetSect()=>%lu\n",sect));
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::GetESect
|
|
//
|
|
// Synposis: Return the nth sector in a chain, extending the chain
|
|
// if necessary.
|
|
//
|
|
// Effects: Modifies fat (via Extend) if necessary
|
|
//
|
|
// Arguments: [sect] -- Sector ID of beginning of chain
|
|
// [ulNum] -- Indicates which sector is to be returned
|
|
// [psectReturn] -- Pointer to storage for return value
|
|
//
|
|
// Returns: S_OK if call completed OK.
|
|
//
|
|
// Algorithm: Linearly search chain until numth sector is found. If
|
|
// the chain terminates early, extend it as necessary.
|
|
//
|
|
// Notes:
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
|
|
SCODE CFat::GetESect(SECT sect, ULONG ulNum, SECT *psectReturn)
|
|
{
|
|
msfDebugOut((DEB_FAT,"In CFat::GetESect(%lu,%lu)\n",sect,ulNum));
|
|
|
|
SCODE sc = S_OK;
|
|
|
|
ULONG i = 0;
|
|
while (i < ulNum)
|
|
{
|
|
SECT temp;
|
|
msfChk(GetNext(sect, &temp));
|
|
|
|
msfAssert(temp != FREESECT &&
|
|
aMsg("FREESECT found in chain."));
|
|
|
|
if (temp == ENDOFCHAIN)
|
|
{
|
|
|
|
//The stream isn't long enough, so extend it somehow.
|
|
ULONG need = ulNum - i;
|
|
|
|
msfAssert((SIDMINIFAT == _sid ||
|
|
sect != _pmsParent->GetHeader()->GetFatStart()) &&
|
|
aMsg("Called GetESect on Fat chain"));
|
|
msfChk(Extend(sect,need));
|
|
}
|
|
else
|
|
{
|
|
sect = temp;
|
|
i++;
|
|
}
|
|
}
|
|
|
|
msfDebugOut((DEB_FAT,"Exiting GetESect with result %lu\n",sect));
|
|
*psectReturn = sect;
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::SetChainLength, private
|
|
//
|
|
// Synposis: Set the length of a fat chain. This is used to reduce
|
|
// the length of the chain only. To extend a chain, use
|
|
// Extend or GetESect
|
|
//
|
|
// Effects: Modifies the fat
|
|
//
|
|
// Arguments: [sectStart] -- Sector to begin at (head of chain)
|
|
// [uLength] -- New length for chain
|
|
//
|
|
// Returns: void.
|
|
//
|
|
// Algorithm: Traverse chain until uLength is reached or the chain
|
|
// terminates. If it terminates prematurely, return with
|
|
// no other action. Otherwise, deallocate all remaining
|
|
// sectors in the chain.
|
|
//
|
|
// Notes:
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
|
|
SCODE CFat::SetChainLength(SECT sectStart, ULONG ulLength)
|
|
{
|
|
msfDebugOut((DEB_FAT,"In CFat::SetChainLength(%lu,%lu)\n",sectStart,ulLength));
|
|
SCODE sc;
|
|
|
|
if (sectStart == ENDOFCHAIN) return S_OK;
|
|
|
|
for (ULONG ui = 0; ui < ulLength; ui++)
|
|
{
|
|
msfChk(GetNext(sectStart, §Start));
|
|
if (sectStart == ENDOFCHAIN) return S_OK;
|
|
}
|
|
|
|
msfAssert(sectStart != ENDOFCHAIN &&
|
|
aMsg("Called SetChainLength is ENDOFCHAIN start"));
|
|
|
|
SECT sectEnd;
|
|
sectEnd = sectStart;
|
|
|
|
msfChk(GetNext(sectStart, §Start));
|
|
if (ulLength != 0)
|
|
{
|
|
msfChk(SetNext(sectEnd, ENDOFCHAIN));
|
|
}
|
|
else
|
|
{
|
|
msfChk(SetNext(sectEnd, FREESECT));
|
|
}
|
|
|
|
while (sectStart != ENDOFCHAIN)
|
|
{
|
|
SECT sectTemp;
|
|
msfChk(GetNext(sectStart, §Temp));
|
|
msfChk(SetNext(sectStart, FREESECT));
|
|
sectStart = sectTemp;
|
|
}
|
|
msfDebugOut((DEB_FAT,"Out CFat::SetChainLength()\n"));
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Method: CFat::FindLast, private
|
|
//
|
|
// Synopsis: Find last used sector in a fat
|
|
//
|
|
// Returns: Location of last used sector
|
|
//
|
|
// Algorithm: Perform a backward linear search until a non-free
|
|
// sector is found.
|
|
//
|
|
// Notes: Used for shadow fats only.
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
SCODE CFat::FindLast(SECT * psectRet)
|
|
{
|
|
SCODE sc = S_OK;
|
|
FSINDEX ipfs = _cfsTable;
|
|
SECT sect = 0;
|
|
|
|
while (ipfs > 0)
|
|
{
|
|
ipfs--;
|
|
|
|
FSOFFSET isect = _fv.GetSectTable();
|
|
|
|
CFatSect *pfs;
|
|
msfChk(_fv.GetTable(ipfs, FB_NONE, &pfs));
|
|
|
|
while (isect > 0)
|
|
{
|
|
isect--;
|
|
|
|
SECT sectCurrent = pfs->GetSect(isect);
|
|
|
|
|
|
if (sectCurrent != FREESECT)
|
|
{
|
|
msfDebugOut((DEB_FAT,"FindLast returns %lu\n",PairToSect(ipfs,isect)));
|
|
sect = PairToSect(ipfs, (FSOFFSET) (isect + 1));
|
|
break;
|
|
}
|
|
}
|
|
|
|
_fv.ReleaseTable(ipfs);
|
|
if (sect != 0)
|
|
break;
|
|
}
|
|
|
|
*psectRet = sect;
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Method: CFat::FindMaxSect, private
|
|
//
|
|
// Synopsis: Return last used sector in current Fat.
|
|
//
|
|
// Arguments: None.
|
|
//
|
|
// Returns: Last used sector in current Fat
|
|
//
|
|
//--------------------------------------------------------------------------
|
|
|
|
SCODE CFat::FindMaxSect(SECT *psectRet)
|
|
{
|
|
SCODE sc = S_OK;
|
|
|
|
if (_sectMax == ENDOFCHAIN)
|
|
{
|
|
msfChk(FindLast(psectRet));
|
|
}
|
|
else
|
|
{
|
|
#if DBG == 1
|
|
SECT sectLast;
|
|
msfChk(FindLast(§Last));
|
|
#endif
|
|
*psectRet = _sectMax;
|
|
}
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|
|
|
|
//+-------------------------------------------------------------------------
|
|
//
|
|
// Member: CFat::Contig, public
|
|
//
|
|
// Synposis: Create contiguous sector table
|
|
//
|
|
// Effects: Creates new CSegment.
|
|
//
|
|
// Arguments: [sect] -- Starting sector for table to begin
|
|
// [ulength] -- Runlength in sectors of table to produce
|
|
//
|
|
// Returns: Pointer to a Segment table
|
|
//
|
|
// Algorithm: Perform calls to CFat::GetNext(). Any call that is
|
|
// 1 higher than the previous represents contiguous blocks.
|
|
// Construct the Segment table on that basis.
|
|
//
|
|
// Notes:
|
|
//
|
|
//---------------------------------------------------------------------------
|
|
|
|
SCODE CFat::Contig(
|
|
SSegment STACKBASED *aseg,
|
|
SECT sect,
|
|
ULONG ulLength)
|
|
{
|
|
msfDebugOut((DEB_ITRACE,"In CFat::Contig(%lu,%lu)\n",sect,ulLength));
|
|
SCODE sc = S_OK;
|
|
SECT stemp = sect;
|
|
ULONG ulCount = 1;
|
|
USHORT iseg = 0;
|
|
|
|
msfAssert(sect != ENDOFCHAIN &&
|
|
aMsg("Called Contig with ENDOFCHAIN start"));
|
|
|
|
aseg[iseg].sectStart = sect;
|
|
aseg[iseg].cSect = 1;
|
|
|
|
while ((ulLength > 1) && (iseg < CSEG))
|
|
{
|
|
msfAssert(sect != ENDOFCHAIN &&
|
|
aMsg("Contig found premature ENDOFCHAIN"));
|
|
|
|
FSINDEX ipfs;
|
|
FSOFFSET isect;
|
|
|
|
SectToPair(sect, &ipfs, &isect);
|
|
|
|
CFatSect *pfs;
|
|
msfChk(_fv.GetTable(ipfs, FB_NONE, &pfs));
|
|
sect = pfs->GetSect(isect);
|
|
_fv.ReleaseTable(ipfs);
|
|
|
|
if (sect == ENDOFCHAIN)
|
|
{
|
|
//Allocate new sectors.
|
|
|
|
SECT sectNew;
|
|
msfChk(GetFree(ulLength - 1, §New));
|
|
msfChk(SetNext(stemp, sectNew));
|
|
sect = sectNew;
|
|
}
|
|
|
|
if (sect != (stemp + 1))
|
|
{
|
|
aseg[iseg].cSect = ulCount;
|
|
ulCount = 1;
|
|
iseg++;
|
|
aseg[iseg].sectStart = sect;
|
|
stemp = sect;
|
|
}
|
|
else
|
|
{
|
|
ulCount++;
|
|
stemp = sect;
|
|
}
|
|
ulLength--;
|
|
}
|
|
|
|
if (iseg < CSEG)
|
|
{
|
|
aseg[iseg].cSect = ulCount;
|
|
aseg[iseg + 1].sectStart = ENDOFCHAIN;
|
|
}
|
|
else
|
|
{
|
|
aseg[iseg].sectStart = FREESECT;
|
|
}
|
|
|
|
msfDebugOut((DEB_ITRACE,"Exiting Contig()\n"));
|
|
|
|
Err:
|
|
return sc;
|
|
}
|
|
|