diskio.pas

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   P := Longint(F.Memory);
   L1 := StartSector;
   if VolumeLock(lLogical) then
      begin
         Result := True;
         while L>MaxSize do
           begin
              Transfer.StartSector := L1;
              Transfer.SectorCount := 100;
              Transfer.Buffer := P;
              R.ESI := 0;
              R.EDX := FVolume;
              R.ECX := $FFFFFFFF;
              R.EBX := Longint(@Transfer);
              R.EAX := $7305;
              L1 := L1+100;
              L := L-MaxSize;
              P := P+MaxSize;
              IOCTL(VWIN32_DIOC_DOS_DRIVEINFO, R);
              Result := Result and (not Odd(R.Flags));
           end;
         Transfer.StartSector := L1;
         Transfer.SectorCount := L div FBytesPerSector;
         Transfer.Buffer := P;
         R.ESI := 0;
         R.EDX := FVolume;
         R.ECX := $FFFFFFFF;
         R.EBX := Longint(@Transfer);
         R.EAX := $7305;
         IOCTL(VWIN32_DIOC_DOS_DRIVEINFO, R);
         Result := Result and (not Odd(R.Flags));
         VolumeUnlock(lLogical);
      end;
   F.Seek(0, 0);
   if nSize > F.Size then F.Read(Buffer, F.Size)
                     else F.Read(Buffer, nSize);
   F.Free;
end;

function TDiskIO.ReadLogicalSector(StartSector, nSectors: Longint; var Buffer; nSize: Longint): Boolean;
var R: T32Regs;
    L, L1: Longint;
    MaxSize: Longint;
    P: Longint;
    W: TWin95;
begin
   FillChar(Buffer, nSize, 0);
   Result := False;
   if (FHandle = 0) or (FVolume = 0) then Exit;
   W := CheckWindows95;
   if W = NoWin95 then Exit;
   if W = OSR2 then
      begin
         Result := ReadLogicalSectorEx(StartSector, nSectors, Buffer, nSize);
         if Result then Exit;
      end;
   if StartSector>=FLogicalSectors-1 then StartSector := FLogicalSectors-1;
   if StartSector+nSectors>FLogicalSectors then nSectors := FLogicalSectors-StartSector;
   MaxSize := FBytesPerSector*100;
   F := TMemoryStream.Create;
   F.SetSize(nSectors*FBytesPerSector);
   L := F.Size;
   P := Longint(F.Memory);
   L1 := StartSector;
   if VolumeLock(lLogical) then
      begin
         Result := True;
         while L>MaxSize do
           begin
              Transfer.StartSector := L1;
              Transfer.SectorCount := 100;
              Transfer.Buffer := P;
              R.EAX := FVolume-1;
              R.ECX := $FFFFFFFF;
              R.EBX := Longint(@Transfer);
              L1 := L1+100;
              L := L-MaxSize;
              P := P+MaxSize;
              IOCTL(VWIN32_DIOC_DOS_INT25, R);
              Result := Result and (not Odd(R.Flags));
           end;
         Transfer.StartSector := L1;
         Transfer.SectorCount := L div FBytesPerSector;
         Transfer.Buffer := P;
         R.EAX := FVolume-1;
         R.ECX := $FFFFFFFF;
         R.EBX := Longint(@Transfer);
         IOCTL(VWIN32_DIOC_DOS_INT25, R);
         Result := Result and (not Odd(R.Flags));
         VolumeUnlock(lLogical);
      end;
   F.Seek(0, 0);
   if nSize > F.Size then F.Read(Buffer, F.Size)
                     else F.Read(Buffer, nSize);
   F.Free;
end;

function TDiskIO.WriteLogicalSectorEx(StartSector, nSectors: Longint; var Buffer; nSize: Longint): Boolean;
var R: T32Regs;
    L, L1: Longint;
    MaxSize: Longint;
    P: Longint;
begin
   Result := False;
   if StartSector>=FLogicalSectors-1 then StartSector := FLogicalSectors-1;
   if StartSector+nSectors>FLogicalSectors then nSectors := FLogicalSectors-StartSector;
   MaxSize := FBytesPerSector*100;
   F := TMemoryStream.Create;
   F.SetSize(nSectors*FBytesPerSector);
   F.Seek(0, 0);
   F.Write(Buffer, F.Size);
   L := F.Size;
   P := Longint(F.Memory);
   L1 := StartSector;
   if VolumeLock(lLogical) then
      begin
         Result := True;
         while L>MaxSize do
           begin
              Transfer.StartSector := L1;
              Transfer.SectorCount := 100;
              Transfer.Buffer := P;
              R.ESI := $6001;
              R.EDX := FVolume;
              R.ECX := $FFFFFFFF;
              R.EBX := Longint(@Transfer);
              R.EAX := $7305;
              L1 := L1+100;
              L := L-MaxSize;
              P := P+MaxSize;
              IOCTL(VWIN32_DIOC_DOS_DRIVEINFO, R);
              Result := Result and (not Odd(R.Flags));
           end;
         Transfer.StartSector := L1;
         Transfer.SectorCount := L div FBytesPerSector;
         Transfer.Buffer := P;
         R.ESI := 1;
         R.EDX := FVolume;
         R.ECX := $FFFFFFFF;
         R.EBX := Longint(@Transfer);
         R.EAX := $7305;
         IOCTL(VWIN32_DIOC_DOS_DRIVEINFO, R);
         Result := Result and (not Odd(R.Flags));
         VolumeUnlock(lLogical);
      end;
   F.Seek(0, 0);
   if nSize > F.Size then F.Read(Buffer, F.Size)
                     else F.Read(Buffer, nSize);
   F.Free;
end;

function TDiskIO.WriteLogicalSector(StartSector, nSectors: Longint; var Buffer; nSize: Longint): Boolean;
var R: T32Regs;
    L, L1: Longint;
    MaxSize: Longint;
    P: Longint;
    W: TWin95;
begin
   Result := False;
   if (FHandle = 0) or (FVolume = 0) then Exit;
   W := CheckWindows95;
   if W = NoWin95 then Exit;
   if W = OSR2 then
      begin
         Result := WriteLogicalSectorEx(StartSector, nSectors, Buffer, nSize);
         if Result then Exit;
      end;
   if StartSector>=FLogicalSectors-1 then StartSector := FLogicalSectors-1;
   if StartSector+nSectors>FLogicalSectors then nSectors := FLogicalSectors-StartSector;
   MaxSize := FBytesPerSector*100;
   F := TMemoryStream.Create;
   F.SetSize(nSectors*FBytesPerSector);
   F.Seek(0, 0);
   F.Write(Buffer, F.Size);
   L := F.Size;
   P := Longint(F.Memory);
   L1 := StartSector;
   if VolumeLock(lLogical) then
      begin
         Result := True;
         while L>MaxSize do
           begin
              Transfer.StartSector := L1;
              Transfer.SectorCount := 100;
              Transfer.Buffer := P;
              R.EAX := FVolume-1;
              R.ECX := $FFFFFFFF;
              R.EBX := Longint(@Transfer);
              L1 := L1+100;
              L := L-MaxSize;
              P := P+MaxSize;
              IOCTL(VWIN32_DIOC_DOS_INT26, R);
              Result := Result and (not Odd(R.Flags));
           end;
         Transfer.StartSector := L1;
         Transfer.SectorCount := L div FBytesPerSector;
         Transfer.Buffer := P;
         R.EAX := FVolume-1;
         R.ECX := $FFFFFFFF;
         R.EBX := Longint(@Transfer);
         IOCTL(VWIN32_DIOC_DOS_INT26, R);
         Result := Result and (not Odd(R.Flags));
         VolumeUnlock(lLogical);
      end;
   F.Free;
end;

procedure TDiskIO.CheckFileSystem;
var P, P1, P2: Pointer;
    I, J: Longint;
    szFSType: String;
    B1, B2: Byte;
    W: Word;
    L: Longint;
begin
   GetMem(P, FBytesPerSector);
   if not ReadLogicalSector(0, 1, P^, FBytesPerSector) then
      begin
         FreeMem(P);
         Exit;
      end;
   if PBOOTSect(P)^.bsFATsecs = 0 then FFileSystem := fsFAT32;
   if FFileSystem = fsFAT32 then
      begin
         FSerial := PBootSect32(P)^.bsVolumeID;
         SetLength(FLabel, 11);
         for I := 1 to 11 do FLabel[I] := PBootSect32(P)^.bsVolumeLabel[I];
         try
           while (Length(FLabel)<>0) and (FLabel[Length(FLabel)]=' ') do
                 Delete(FLabel, Length(FLabel), 1);
         except
           on Exception do;
         end;
         FSectorsPerCluster := PBootSect32(P)^.bpb.A_BF_BPB_SectorsPerCluster;
         FFATCount := PBootSect32(P)^.bpb.A_BF_BPB_NumberOfFATs;
         GetMem(FFATSector, FFATCount*4);
         I := PBootSect32(P)^.bpb.A_BF_BPB_ReservedSectors;
         Longint(FFATSector^) := I;
         FSectorsPerFAT := PBootSect32(P)^.bpb.A_BF_BPB_BigSectorsPerFatHi;
         FSectorsPerFAT := (FSectorsPerFAT shl 16)+PBootSect32(P)^.bpb.A_BF_BPB_BigSectorsPerFat;
         P1 := FFATSector;
         Inc(Longint(P1), 4);
         if FFATCount>1 then
            for J := 2 to FFATCount do
                begin
                   I := I+FSectorsPerFAT;
                   Longint(P1^) := I;
                   Inc(Longint(P1), 4);
                end;
         FRootDirCluster := PBootSect32(P)^.bpb.A_BF_BPB_RootDirStrtClusHi;
         FRootDirCluster := (FRootDirCluster shl 16)+PBootSect32(P)^.bpb.A_BF_BPB_RootDirStrtClus;
         FRootDirSector :=  PBootSect32(P)^.bpb.A_BF_BPB_ReservedSectors+FFATCount*FSectorsPerFAT;
         FRootDirSector := FRootDirSector+(FRootDirCluster-2)*FSectorsPerCluster;
         FCluster2Sector := FRootDirSector;
      end else
      begin
         FSerial := PBootSect(P)^.bsVolumeID;
         SetLength(FLabel, 11);
         for I := 1 to 11 do FLabel[I] := PBootSect(P)^.bsVolumeLabel[I];
         try
           while (Length(FLabel)<>0) and (FLabel[Length(FLabel)]=' ') do
                 Delete(FLabel, Length(FLabel), 1);
         except
           on Exception do;
         end;
         SetLength(szFSType, 8);
         FillChar(szFSType[1], 8, 0);
         Move(PBootSect(P)^.bsFileSysType, szFSType[1], 8);
         try
           while (Length(szFSType) <> 0) and (szFSType[Length(szFSType)] = ' ') do
             Delete(szFSType, Length(szFSType), 1);
         except
           on Exception do;
         end;
         if strcomp(PChar(szFSType), 'FAT12') = 0 then FFileSystem := fsFAT12 else
         if strcomp(PChar(szFSType), 'FAT16') = 0 then FFileSystem := fsFAT16;
         FSectorsPerCluster := PBootSect(P)^.bsSecPerClust;
         FFATCount := PBootSect(P)^.bsFATs;
         GetMem(FFATSector, FFATCount*4);
         FSectorsPerFAT := PBootSect(P)^.bsFATsecs;
         I := PBootSect(P)^.bsResSectors;
         Longint(FFATSector^) := I;
         P1 := FFATSector;
         Inc(Longint(P1), 4);
         if FFATCount>1 then
            for J := 2 to FFATCount do
                begin
                   I := I+FSectorsPerFAT;
                   Longint(P1^) := I;
                   Inc(Longint(P1), 4);
                end;
         FRootDirEntries := PBootSect(P)^.bsRootDirEnts;
         FRootDirSector := PBootSect(P)^.bsResSectors+FSectorsPerFAT*FFATCount;
         FRootDirCluster := 1;
         FCluster2Sector := FRootDirSector+((FRootDirEntries*32+FBytesPerSector-1) div FBytesPerSector);
      end;
   FLabel := UpperCase(FLabel);   
   FEndingCluster := ((FLogicalSectors-FCluster2Sector) div FSectorsPerCluster)+1;
   FreeMem(P);
   if FFileSystem = fsNone then Exit;
   {Read FAT}
   GetMem(P, FSectorsPerFAT*FFATCount*FBytesPerSector);
   if not ReadLogicalSector(FATSector[1], FSectorsPerFAT*FFATCount, P^, FBytesPerSector*FSectorsPerFAT*FFATCount) then
      begin
         FreeMem(P);
         Exit;
      end;
   FFATSize := FEndingCluster-1;
   GetMem(FFAT, FFATSize*FFATCount*4);
   FillChar(FFAT^, FFATSize*FFATCount*4, 0);
   P2 := FFAT;
   if FFileSystem = fsFAT12 then
      begin
         for J := 0 to FFATCount-1 do
             begin
                P1 := Pointer(Longint(P)+J*FSectorsPerFAT*FBytesPerSector+3);
                for I := 1 to FFATSize div 2 do
                    begin
                       B1 := Byte(P1^); Inc(Longint(P1));
                       B2 := Byte(P1^) and $0F;
                       W := B2; W := (W shl 8) or B1;
                       L := W;
                       Longint(P2^) := L and FAT_MASK_12;
                       Inc(Longint(P2), 4);
                       B1 := Byte(P1^) and $F0; Inc(Longint(P1));
                       B2 := Byte(P1^); Inc(Longint(P1));
                       W := B2; W := (W shl 4) or (B1 shr 4);
                       L := W;
                       Longint(P2^) := L and FAT_MASK_12;
                       Inc(Longint(P2), 4);
                    end;
                if Odd(FFATSize) then
                   begin
                      B1 := Byte(P1^); Inc(Longint(P1));
                      B2 := Byte(P1^) and $0F;
                      W := B2; W := (W shl 8) or B1;
                      L := W;
                      Longint(P2^) := L and FAT_MASK_12;
                   end;
             end;
      end else
   if FFileSystem = fsFAT16 then
      begin
         for J := 0 to FFATCount-1 do
             begin
                P1 := Pointer(Longint(P)+J*FSectorsPerFAT*FBytesPerSector+4);
                for I := 1 to FFATSize do
                    begin
                       L := Word(P1^); Inc(Longint(P1), 2);
                       Longint(P2^) := L and FAT_MASK_16;
                       Inc(Longint(P2), 4);
                    end;
             end;
      end else
      begin