fpspreadsheet: Extend TBufStream for reading. Rename workbook's WritingOptions to Options, and the option flags from woXXXX to boXXXX. Use boBufStream (former woBufStream) to activate TBufStream for reading of xls and ods. Speed up reading of biff2 by factor 3 (rel to commit before prev one). Fix pile-up of temporary files when saving ods.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@3357 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/fpspreadsheet/examples/fpsSpeedTest/mainform.pas

@@ -45,10 +45,8 @@ type
       var AValue: Variant; var AStyleCell: PCell);
     procedure ReadFromIni;
     procedure WriteToIni;
-    procedure RunReadTest(Idx: Integer; Log: String;
+    procedure RunReadTest(Idx: Integer; Log: String; Options: TsWorkbookOptions);
-      Options: TsWorkbookWritingOptions);
+    procedure RunWriteTest(Idx: integer; Rows: integer; Log: string; Options: TsWorkbookOptions);
-    procedure RunWriteTest(Idx: integer; Rows: integer; Log: string;
-      Options: TsWorkbookWritingOptions);
     procedure StatusMsg(const AMsg: String);
   public
     { public declarations }
@@ -80,6 +78,8 @@ const
   rc100k = 6;
 
   CONTENT_PREFIX: array[0..2] of Char = ('S', 'N', 'M');
+  CONTENT_TEXT: array[0..2] of string = ('strings only', 'numbers only', '50% strings and 50% numbers');
+
   FORMAT_EXT: array[0..4] of String = ('.ods', '.xlsx', '.xls', '_b5.xls', '_b2.xls');
   SPREAD_FORMAT: array[0..4] of TsSpreadsheetFormat = (sfOpenDocument, sfOOXML, sfExcel8, sfExcel5, sfExcel2);
 
@@ -116,7 +116,7 @@ begin
 end;
 
 procedure TForm1.RunReadTest(Idx: Integer; Log: String;
-  Options: TsWorkbookWritingOptions);
+  Options: TsWorkbookOptions);
 var
   MyWorkbook: TsWorkbook;
   MyWorksheet: TsWorksheet;
@@ -127,9 +127,7 @@ var
   ok: Boolean;
 begin
   s := Trim(Log);
-
   Log := Log + '         ';
-
   try
     for i := 0 to CgFormats.Items.Count-1 do begin
       if FEscape then begin
@@ -162,6 +160,7 @@ begin
         MyWorkbook := TsWorkbook.Create;
         try
           Application.ProcessMessages;
+          MyWorkbook.Options := Options;
           Tm := GetTickCount;
           try
             MyWorkbook.ReadFromFile(fname, SPREAD_FORMAT[i]);
@@ -184,7 +183,7 @@ begin
 end;
 
 procedure TForm1.RunWriteTest(Idx: integer; Rows: integer; Log: string;
-  Options: TsWorkbookWritingOptions);
+  Options: TsWorkbookOptions);
 var
   MyWorkbook: TsWorkbook;
   MyWorksheet: TsWorksheet;
@@ -201,13 +200,13 @@ begin
     end;
 
     MyWorksheet := MyWorkbook.AddWorksheet('Sheet1');
-    MyWorkbook.WritingOptions := Options;
+    MyWorkbook.Options := Options;
 
     Application.ProcessMessages;
     Tm := GetTickCount;
 
     try
-      if woVirtualMode in Options then
+      if boVirtualMode in Options then
       begin
         MyWorkbook.VirtualRowCount := Rows;
         MyWorkbook.VirtualColCount := COLCOUNT;
@@ -222,7 +221,7 @@ begin
         for ARow := 0 to Rows - 1 do
         begin
           if ARow mod 1000 = 0 then begin
-            StatusMsg(Format('Populating row %d', [ARow]));
+            StatusMsg(Format('Building row %d...', [ARow]));
             if FEscape then begin
               Log := 'Test aborted';
               exit;
@@ -236,7 +235,8 @@ begin
             1: for ACol := 0 to COLCOUNT-1 do
                  MyWorksheet.WriteNumber(ARow, ACol, 1E5*ARow + ACol);
             2: for ACol := 0 to COLCOUNT-1 do
-                 if (odd(ARow) and odd(ACol)) or odd(ARow+ACol) then begin
+                 if (odd(ARow) and odd(ACol)) or odd(ARow+ACol) then
+                 begin
                    S := 'Xy' + IntToStr(ARow) + 'x' + IntToStr(ACol);
                    MyWorksheet.WriteUTF8Text(ARow, ACol, S);
                  end else
@@ -255,7 +255,8 @@ begin
 
     Log := Log + '  ' + format('%5.1f  ', [(GetTickCount - Tm) / 1000]);
 
-    for k := 0 to CgFormats.Items.Count-1 do begin
+    for k := 0 to CgFormats.Items.Count-1 do
+    begin
       if FEscape then begin
         Log := 'Test aborted';
         exit;
@@ -313,16 +314,11 @@ begin
   FEscape := false;
   EnableControls(false);
 
-  try
   Memo.Append     ('Running: Reading TsWorkbook from various file formats');
-    case RgContent.ItemIndex of
+  Memo.Append     ('         Worksheet contains ' + CONTENT_TEXT[RgContent.ItemIndex]);
-      0: Memo.Append('         Worksheet contains strings only');
-      1: Memo.Append('         Worksheet contains numbers only');
-      2: Memo.Append('         Worksheet contains 50% strings and 50% numbers');
-    end;
   Memo.Append     ('         (Times in seconds)');
      //'-----------                        .ods  .xlsx  biff8  biff5  biff2');
-       //'Rows x Cols  W.Options     Build  Write  Write  Write  Write  Write'
+     //'Rows x Cols  Options       Build  Write  Write  Write  Write  Write'
   s := '--------------------------------  ';
   if CgFormats.Checked[fmtODS]  then s := s + ' .ods  ';
   if CgFormats.Checked[fmtXLSX] then s := s + '.xlsx  ';
@@ -330,7 +326,7 @@ begin
   if CgFormats.Checked[fmtXLS5] then s := s + 'biff5  ';
   if CgFormats.Checked[fmtXLS2] then s := s + 'biff2';
   Memo.Append(TrimRight(s));
-    s := 'Rows x Cols  W.Options            ';
+  s := 'Rows x Cols  Options              ';
   if CgFormats.Checked[fmtODS]  then s := s + ' Read  ';
   if CgFormats.Checked[fmtXLSX] then s := s + ' Read  ';
   if CgFormats.Checked[fmtXLS8] then s := s + ' Read  ';
@@ -341,6 +337,7 @@ begin
   len := Length(s);
   Memo.Append(DupeString('-', len));
 
+  try
     for i:=0 to CgRowCount.Items.Count-1 do begin
       if FEscape then
         exit;
@@ -351,12 +348,16 @@ begin
       rows := GetRowCount(i);
       s := Format('%7.0nx%d', [1.0*rows, COLCOUNT]);
 
+      if CbVirtualModeOnly.Checked then begin
+        //RunReadTest(2, s + '  [boVM      ]', [boVirtualMode]);
+        //RunReadTest(4, s + '  [boVM, boBS]', [boVirtualMode, boBufStream]);
+      end else begin
         RunReadTest(1, s + '  [          ]', []);
-      (*
+        //RunReadTest(2, s + '  [boVM      ]', [boVirtualMode]);
-      RunReadTest(2, s + '  [woVM      ]', [woVirtualMode]);
+        RunReadTest(3, s + '  [      boBS]', [boBufStream]);
-      RunReadTest(3, s + '  [      woBS]', [woBufStream]);
+        //RunReadTest(4, s + '  [boVM, boBS]', [boVirtualMode, boBufStream]);
-      RunReadTest(4, s + '  [woVM, woBS]', [woVirtualMode, woBufStream]);
+      end;
-      *)
+
       Memo.Append(DupeString('-', len));
     end;
     Memo.Append('Ready');
@@ -378,14 +379,10 @@ begin
   EnableControls(false);
 
   Memo.Append     ('Running: Building TsWorkbook and writing to different file formats');
-  case RgContent.ItemIndex of
+  Memo.Append     ('         Worksheet contains ' + CONTENT_TEXT[RgContent.ItemIndex]);
-    0: Memo.Append('         Worksheet contains strings only');
-    1: Memo.Append('         Worksheet contains numbers only');
-    2: Memo.Append('         Worksheet contains 50% strings and 50% numbers');
-  end;
   Memo.Append     ('         (Times in seconds)');
      //'-----------                        .ods  .xlsx  biff8  biff5  biff2');
-     //'Rows x Cols  W.Options     Build  Write  Write  Write  Write  Write'
+     //'Rows x Cols  Options       Build  Write  Write  Write  Write  Write'
   s := '--------------------------------  ';
   if CgFormats.Checked[fmtODS]  then s := s + ' .ods  ';
   if CgFormats.Checked[fmtXLSX] then s := s + '.xlsx  ';
@@ -393,7 +390,7 @@ begin
   if CgFormats.Checked[fmtXLS5] then s := s + 'biff5  ';
   if CgFormats.Checked[fmtXLS2] then s := s + 'biff2';
   Memo.Append(TrimRight(s));
-  s := 'Rows x Cols  W.Options     Build  ';
+  s := 'Rows x Cols  Options       Build  ';
   if CgFormats.Checked[fmtODS]  then s := s + 'Write  ';
   if CgFormats.Checked[fmtXLSX] then s := s + 'Write  ';
   if CgFormats.Checked[fmtXLS8] then s := s + 'Write  ';
@@ -414,13 +411,13 @@ begin
       Rows := GetRowCount(i);
       s := Format('%7.0nx%d', [1.0*Rows, COLCOUNT]);
       if CbVirtualModeOnly.Checked then begin
-        RunWriteTest(2, Rows, s + '  [woVM      ]', [woVirtualMode]);
+        RunWriteTest(2, Rows, s + '  [boVM      ]', [boVirtualMode]);
-        RunWriteTest(4, Rows, s + '  [woVM, woBS]', [woVirtualMode, woBufStream]);
+        RunWriteTest(4, Rows, s + '  [boVM, boBS]', [boVirtualMode, boBufStream]);
       end else begin
         RunWriteTest(1, Rows, s + '  [          ]', []);
-        RunWriteTest(2, Rows, s + '  [woVM      ]', [woVirtualMode]);
+        RunWriteTest(2, Rows, s + '  [boVM      ]', [boVirtualMode]);
-        RunWriteTest(3, Rows, s + '  [      woBS]', [woBufStream]);
+        RunWriteTest(3, Rows, s + '  [      boBS]', [boBufStream]);
-        RunWriteTest(4, Rows, s + '  [woVM, woBS]', [woVirtualMode, woBufStream]);
+        RunWriteTest(4, Rows, s + '  [boVM, boBS]', [boVirtualMode, boBufStream]);
       end;
       Memo.Append(DupeString('-', len));
     end;
@@ -450,6 +447,7 @@ begin
   CgRowCount.Enabled := AEnable;
   LblCancel.Visible := not AEnable;
   StatusMsg('');
+  Application.ProcessMessages;
 end;
 
 procedure TForm1.FormCreate(Sender: TObject);

components/fpspreadsheet/examples/other/test_virtualmode.lpr

@@ -64,17 +64,17 @@ begin
 
       { These are the essential commands to activate virtual mode: }
 
-//      workbook.WritingOptions := [woVirtualMode, woBufStream];
+      workbook.Options := [boVirtualMode, boBufStream];
-      workbook.WritingOptions := [woVirtualMode];
+//      workbook.Options := [boVirtualMode];
-      { woBufStream can be omitted, but is important for large files: it causes
+      { boBufStream can be omitted, but is important for large files: it causes
         writing temporary data to a buffered file stream instead of a pure
-        memory stream which can overflow memory. The option can slow down the
+        memory stream which can overflow memory. In cases, the option can slow
-        writing process a bit. }
+        down the writing process a bit. }
 
       { Next two numbers define the size of virtual spreadsheet.
         In case of a database, VirtualRowCount is the RecordCount, VirtualColCount
         the number of fields to be written to the spreadsheet file }
-      workbook.VirtualRowCount := 20000;
+      workbook.VirtualRowCount := 5000;
       workbook.VirtualColCount := 100;
 
       { The event handler for OnNeedCellData links the workbook to the method
@@ -95,8 +95,10 @@ begin
       { In case of a database, you would open the dataset before calling this: }
 
       t := Now;
-      //workbook.WriteToFile('test_virtual.xlsx', sfOOXML, true);
+      workbook.WriteToFile('test_virtual.xlsx', sfOOXML, true);
-      workbook.WriteToFile('test_virtual.xls', sfExcel8, true);
+      //workbook.WriteToFile('test_virtual.xls', sfExcel8, true);
+      //workbook.WriteToFile('test_virtual.xls', sfExcel5, true);
+      //workbook.WriteToFile('test_virtual.xls', sfExcel2, true);
       t := Now - t;
 
     finally

components/fpspreadsheet/fpsopendocument.pas

@@ -193,7 +193,7 @@ type
 implementation
 
 uses
-  StrUtils;
+  StrUtils, fpsStreams;
 
 const
   { OpenDocument general XML constants }
@@ -1191,8 +1191,23 @@ var
     parser: TDOMParser;
     src: TXMLInputSource;
     stream: TStream;
+//    fstream: TStream;
   begin
+    {
+    if (boBufStream in Workbook.Options) then begin
+      fstream := TFileStream.Create(AFilename, fmOpenRead + fmShareDenyWrite);
+      stream := TMemorystream.Create;
+      stream.CopyFrom(fstream, fstream.Size);
+      stream.Position := 0;
+      fstream.free;
+    end
+    }
+
+    if (boBufStream in Workbook.Options) then
+      stream := TBufStream.Create(AFileName, fmOpenRead + fmShareDenyWrite)
+    else
       stream := TFileStream.Create(AFileName, fmOpenRead + fmShareDenyWrite);
+
     try
       parser := TDOMParser.Create;
       try
@@ -2239,7 +2254,14 @@ procedure TsSpreadOpenDocWriter.CreateStreams;
 var
   dir: String;
 begin
-  if (woBufStream in Workbook.WritingOptions) then begin
+  if (boBufStream in Workbook.Options) then begin
+    FSMeta := TBufStream.Create(GetTempFileName('', 'fpsM'));
+    FSSettings := TBufStream.Create(GetTempFileName('', 'fpsS'));
+    FSStyles := TBufStream.Create(GetTempFileName('', 'fpsSTY'));
+    FSContent := TBufStream.Create(GetTempFileName('', 'fpsC'));
+    FSMimeType := TBufStream.Create(GetTempFileName('', 'fpsMT'));
+    FSMetaInfManifest := TBufStream.Create(GetTempFileName('', 'fpsMIM'));
+    {
     dir := IncludeTrailingPathDelimiter(GetTempDir);
     FSMeta := TFileStream.Create(GetTempFileName(dir, 'fpsM'), fmCreate+fmOpenRead);
     FSSettings := TFileStream.Create(GetTempFileName(dir, 'fpsS'), fmCreate+fmOpenRead);
@@ -2247,6 +2269,7 @@ begin
     FSContent := TFileStream.Create(GetTempFileName(dir, 'fpsC'), fmCreate+fmOpenRead);
     FSMimeType := TFileStream.Create(GetTempFileName(dir, 'fpsMT'), fmCreate+fmOpenRead);
     FSMetaInfManifest := TFileStream.Create(GetTempFileName(dir, 'fpsMIM'), fmCreate+fmOpenRead);
+    }
   end else begin;
     FSMeta := TMemoryStream.Create;
     FSSettings := TMemoryStream.Create;

components/fpspreadsheet/fpspreadsheet.pas

@@ -699,22 +699,33 @@ type
   end;
 
   {@@
-    Options considered when writing a workbook
+    Option flags for the workbook
 
-    @param  woVirtualMode   If in virtual mode date are not taken from cells
+    @param  boVirtualMode   If in virtual mode date are not taken from cells
                             when a spreadsheet is written to file, but are
                             provided by means of the event OnNeedCellData.
-    @param  woBufStream     When this option is set a buffered stream is used
+    @param  boBufStream     When this option is set a buffered stream is used
-                            for writing (a memory stream swapping to disk) }
+                            for writing (a memory stream swapping to disk) or
-  TsWorkbookWritingOption = (woVirtualMode, woBufStream);
+                            reading (a file stream pre-reading chunks of data
+                            to memory) }
+  TsWorkbookOption = (boVirtualMode, boBufStream);
 
   {@@
-    Options considered when writing a workbook }
+    Set of options flags for the workbook }
-  TsWorkbookWritingOptions = set of TsWorkbookWritingOption;
+  TsWorkbookOptions = set of TsWorkbookOption;
 
+  {@@
+    Event fired when writing a file in virtual mode. The event handler has to
+    pass data ("AValue") and formatting ("AStyleCell") to the writer }
   TsWorkbookNeedCellDataEvent = procedure(Sender: TObject; ARow, ACol: Cardinal;
     var AValue: variant; var AStyleCell: PCell) of object;
 
+  {@@
+    Event fired when reading a file in virtual mode. The event handler has to
+    process the data provided by the read in the "ADataCell". }
+  TsWorkbookHaveCellDataEvent = procedure(Sender: TObject; ARow, ACol: Cardinal;
+    const ADataCell: PCell) of object;
+
   {@@
     The workbook contains the worksheets and provides methods for reading from
     and writing to file.
@@ -734,8 +745,9 @@ type
     FVirtualColCount: Cardinal;
     FVirtualRowCount: Cardinal;
     FWriting: Boolean;
-    FWritingOptions: TsWorkbookWritingOptions;
+    FOptions: TsWorkbookOptions;
     FOnNeedCellData: TsWorkbookNeedCellDataEvent;
+    FOnHaveCellData: TsWorkbookHaveCellDataEvent;
     FFileName: String;
 
     { Setter/Getter }
@@ -824,11 +836,15 @@ type
     property ReadFormulas: Boolean read FReadFormulas write FReadFormulas;
     property VirtualColCount: cardinal read FVirtualColCount write SetVirtualColCount;
     property VirtualRowCount: cardinal read FVirtualRowCount write SetVirtualRowCount;
-    property WritingOptions: TsWorkbookWritingOptions read FWritingOptions write FWritingOptions;
+    property Options: TsWorkbookOptions read FOptions write FOptions;
     {@@ This event allows to provide external cell data for writing to file,
       standard cells are ignored. Intended for converting large database files
-      to s spreadsheet format. Requires WritingOption woVirtualMode to be set. }
+      to a spreadsheet format. Requires Option boVirtualMode to be set. }
     property OnNeedCellData: TsWorkbookNeedCellDataEvent read FOnNeedCellData write FOnNeedCellData;
+    {@@ This event accepts cell data while reading a spreadsheet file. Data are
+      not encorporated in a spreadsheet, they are just passed through to the
+      event handler for processing. Requires Optio boVirtualMode to be set. }
+    property OnHaveCellData: TsWorkbookHaveCellDataEvent read FOnHaveCellData write FOnHaveCellData;
   end;
 
   {@@ Contents of a number format record }
@@ -4188,7 +4204,7 @@ var
   sheet: TsWorksheet;
   r1,r2, c1,c2: Cardinal;
 begin
-  if (woVirtualMode in WritingOptions) then begin
+  if (boVirtualMode in Options) then begin
     ALastRow := FVirtualRowCount - 1;
     ALastCol := FVirtualColCount - 1;
   end else begin
@@ -5313,9 +5329,28 @@ end;
   @see    TsWorkbook
 }
 procedure TsCustomSpreadReader.ReadFromFile(AFileName: string; AData: TsWorkbook);
+{
 var
-  InputFile: TFileStream;
+  fs, ms: TStream;
 begin
+  fs := TFileStream.Create(AFileName, fmOpenRead);
+  ms := TMemoryStream.Create;
+  try
+    ms.CopyFrom(fs, fs.Size);
+    ms.Position := 0;
+    ReadFromStream(ms, AData);
+  finally
+    ms.Free;
+    fs.Free;
+  end;
+end;
+ }
+var
+  InputFile: TStream;
+begin
+  if (boBufStream in Workbook.Options) then
+    InputFile := TBufStream.Create(AFileName, fmOpenRead)
+  else
     InputFile := TFileStream.Create(AFileName, fmOpenRead);
   try
     ReadFromStream(InputFile, AData);
@@ -5495,7 +5530,7 @@ procedure TsCustomSpreadWriter.GetSheetDimensions(AWorksheet: TsWorksheet;
 begin
   AFirstRow := 0;
   AFirstCol := 0;
-  if (woVirtualMode in AWorksheet.Workbook.WritingOptions) then begin
+  if (boVirtualMode in AWorksheet.Workbook.Options) then begin
     ALastRow := AWorksheet.Workbook.VirtualRowCount-1;
     ALastCol := AWorksheet.Workbook.VirtualColCount-1;
   end else begin
@@ -5751,7 +5786,7 @@ begin
   if AOverwriteExisting then lMode := fmCreate or fmOpenWrite
   else lMode := fmCreate;
 
-  if (woBufStream in Workbook.WritingOptions) then
+  if (boBufStream in Workbook.Options) then
     OutputFile := TBufStream.Create(AFileName, lMode)
   else
     OutputFile := TFileStream.Create(AFileName, lMode);

components/fpspreadsheet/fpsstreams.pas

@@ -5,8 +5,8 @@ interface
 uses
   SysUtils, Classes;
 
-const
+var
-  DEFAULT_STREAM_BUFFER_SIZE = 1024 * 1024;
+  DEFAULT_STREAM_BUFFER_SIZE: Integer = 1024 * 1024;       // 1 MB
 
 type
   { A buffered stream }
@@ -23,13 +23,15 @@ type
     procedure CreateFileStream;
     function GetPosition: Int64; override;
     function GetSize: Int64; override;
+    function IsWritingMode: Boolean;
   public
     constructor Create(AFileName: String; AMode: Word;
-      ABufSize: Cardinal = DEFAULT_STREAM_BUFFER_SIZE); overload;
+      ABufSize: Cardinal = Cardinal(-1)); overload;
     constructor Create(ATempFile: String; AKeepFile: Boolean = false;
-      ABufSize: Cardinal = DEFAULT_STREAM_BUFFER_SIZE); overload;
+      ABufSize: Cardinal = Cardinal(-1)); overload;
-    constructor Create(ABufSize: Cardinal = DEFAULT_STREAM_BUFFER_SIZE); overload;
+    constructor Create(ABufSize: Cardinal = Cardinal(-1)); overload;
     destructor Destroy; override;
+    procedure FillBuffer;
     procedure FlushBuffer;
     function Read(var Buffer; Count: Longint): Longint; override;
     function Seek(const Offset: Int64; Origin: TSeekOrigin): Int64; override;
@@ -51,18 +53,19 @@ end;
 
 {@@
   Constructor of the TBufStream. Creates a memory stream and prepares everything
-  to create also a file stream if the streamsize exceeds ABufSize bytes.
+  to create also a file stream if the stream size exceeds ABufSize bytes.
 
   @param  ATempFile   File name for the file stream. If an empty string is
                       used a temporary file name is created by calling GetTempFileName.
-  @param  AKeepFile   If true the stream is flushed to file when the stream is
+  @param  AKeepFile   If true and the stream is in WritingMode the stream is
+                      flushed to file when the stream is
                       destroyed. If false the file is deleted when the stream
                       is destroyed.
   @param  ABufSize    Maximum size of the memory stream before swapping to file
                       starts. Value is given in bytes.
 }
 constructor TBufStream.Create(ATempFile: String; AKeepFile: Boolean = false;
-  ABufSize: Cardinal = DEFAULT_STREAM_BUFFER_SIZE);
+  ABufSize: Cardinal = Cardinal(-1));
 begin
   if ATempFile = '' then
     ATempFile := ChangeFileExt(GetTempFileName, '.~abc');
@@ -73,6 +76,9 @@ begin
   FMemoryStream := TMemoryStream.Create;
   // The file stream is only created when needed because of possible conflicts
   // of random file names.
+  if ABufSize = Cardinal(-1) then
+    FBufSize := DEFAULT_STREAM_BUFFER_SIZE
+  else
     FBufSize := ABufSize;
   FFileMode := fmCreate + fmOpenRead;
 end;
@@ -86,7 +92,7 @@ end;
   @param  ABufSize    Maximum size of the memory stream before swapping to file
                       starts. Value is given in bytes.
 }
-constructor TBufStream.Create(ABufSize: Cardinal = DEFAULT_STREAM_BUFFER_SIZE);
+constructor TBufStream.Create(ABufSize: Cardinal = Cardinal(-1));
 begin
   Create('', false, ABufSize);
 end;
@@ -103,9 +109,12 @@ end;
                       starts. Value is given in bytes.
 }
 constructor TBufStream.Create(AFileName: String; AMode: Word;
-  ABufSize: Cardinal = DEFAULT_STREAM_BUFFER_SIZE);
+  ABufSize: Cardinal = Cardinal(-1));
+var
+  keep: Boolean;
 begin
-  Create(AFileName, true, ABufSize);
+  keep := AMode and (fmCreate + fmOpenWrite) <> 0;
+  Create(AFileName, keep, ABufSize);
   FFileMode := AMode;
 end;
 
@@ -117,7 +126,8 @@ begin
   // Free streams and delete temporary file, if requested
   FreeAndNil(FMemoryStream);
   FreeAndNil(FFileStream);
-  if not FKeepTmpFile and (FFileName <> '') then DeleteFile(FFileName);
+  if not FKeepTmpFile and (FFileName <> '') and IsWritingMode then
+    DeleteFile(FFileName);
 
   inherited Destroy;
 end;
@@ -133,10 +143,25 @@ begin
   end;
 end;
 
+{ Reads FBufSize bytes from the stream into the buffer }
+procedure TBufStream.FillBuffer;
+var
+  p, n: Int64;
+begin
+  p := GetPosition;
+  FMemoryStream.Clear;
+  FMemoryStream.Position := 0;
+  FFileStream.Position := p;
+  n := Min(FBufSize, FFileStream.Size - p);
+  FMemoryStream.CopyFrom(FFileStream, n);
+  FMemoryStream.Position := 0;
+  FFileStream.Position := p;
+end;
+
 { Flushes the contents of the memory stream to file }
 procedure TBufStream.FlushBuffer;
 begin
-  if (FMemoryStream.Size > 0) and not FBufWritten then begin
+  if (FMemoryStream.Size > 0) and not FBufWritten and IsWritingMode then begin
     FMemoryStream.Position := 0;
     CreateFileStream;
     FFileStream.CopyFrom(FMemoryStream, FMemoryStream.Size);
@@ -161,12 +186,32 @@ function TBufStream.GetSize: Int64;
 var
   n: Int64;
 begin
+  if IsWritingMode then begin
     if FFileStream <> nil then
       n := FFileStream.Size
     else
       n := 0;
     if n = 0 then n := FMemoryStream.Size;
     Result := Max(n, GetPosition);
+  end else begin
+    CreateFileStream;
+    Result := FFileStream.Size;
+  end;
+end;
+
+{@@
+  Returns true if the stream is in WritingMode.
+  "WritingMode" means that the stream is primarily used for writing. The
+  memory stream is initially empty but fills during writing, it is written to
+  disk when it is full.
+  The (unnamend) opposite of "WritingMode" indicates that the stream is used
+  for reading. The memory stream is initially full, but the stream pointer is at
+  it start. When data are read the stream pointer advances towards the end.
+  When the requested data are not contained in the memory stream another
+  ABufSize of bytes are read into the memory stream. }
+function TBufStream.IsWritingMode: Boolean;
+begin
+  Result := FFileMode and (fmCreate + fmOpenWrite) <> 0;
 end;
 
 {@@
@@ -180,28 +225,39 @@ end;
   @return Number of bytes that were read from the stream.}
 function TBufStream.Read(var Buffer; Count: Longint): Longint;
 begin
-  // Case 1: All "Count" bytes are contained in memory stream
+  // Case 1: Memory stream is empty
+  if FMemoryStream.Size = 0 then begin
+    CreateFileStream;
+    if IsWritingMode then begin
+      Result := FFileStream.Read(Buffer, Count);
+    end else begin
+      FillBuffer;
+      Result := FMemoryStream.Read(Buffer, Count);
+    end;
+    exit;
+  end;
+
+  // Case 2: All "Count" bytes are contained in memory stream
   if FMemoryStream.Position + Count <= FMemoryStream.Size then begin
     Result := FMemoryStream.Read(Buffer, Count);
     exit;
   end;
 
-  // Case 2: Memory stream is empty
-  if FMemoryStream.Size = 0 then begin
-    CreateFileStream;
-    Result := FFileStream.Read(Buffer, Count);
-    exit;
-  end;
-
   // Case 3: Memory stream is not empty but contains only part of the bytes requested
+  if IsWritingMode then begin
     FlushBuffer;
     Result := FFileStream.Read(Buffer, Count);
+  end else begin
+    FillBuffer;
+    Result := FMemoryStream.Read(Buffer, Count);
+  end;
 end;
 
 function TBufStream.Seek(const Offset: Int64; Origin: TSeekOrigin): Int64;
 var
   oldPos: Int64;
   newPos: Int64;
+  n: Int64;
 begin
   oldPos := GetPosition;
   case Origin of
@@ -226,8 +282,20 @@ begin
   end;
 
   // case #3: New position is outside buffer
+  if IsWritingMode then
     FlushBuffer;
   FFileStream.Position := newPos;
+  FMemoryStream.Position := 0;
+  if not IsWritingMode then begin
+    FillBuffer;
+    {
+    FMemoryStream.Position := 0;
+    n := Min(FBufSize, FFileStream.Size - newPos);
+    FMemoryStream.CopyFrom(FFileStream, n);
+    FFileStream.Position := newPos;
+    FMemoryStream.Position := 0;
+    }
+  end;
 end;
 
 function TBufStream.Write(const ABuffer; ACount: LongInt): LongInt;

components/fpspreadsheet/tests/internaltests.pas

@@ -51,6 +51,7 @@ type
     // Write out date cell and try to read as UTF8; verify if contents the same
     procedure ReadDateAsUTF8;
     // Test buffered stream
+    procedure TestReadBufStream;
     procedure TestBufStream;
 
     // Virtual mode tests for all file formats
@@ -252,6 +253,95 @@ begin
   end;
 end;
 
+procedure TSpreadInternalTests.TestReadBufStream;
+const
+  BUF_SIZE = 1024;
+  FILE_SIZE = 2000;
+var
+  tempFileName: String;
+  stream: TStream;
+  writedata: array of Byte;
+  readdata: array of Byte;
+  i, n, nread: Integer;
+begin
+  RandSeed := 0;
+
+  // Create a test file
+  tempFileName := GetTempFileName;
+  stream := TFileStream.Create(tempFileName, fmCreate);
+  try
+    SetLength(writedata, FILE_SIZE);
+    for i:=0 to High(writedata) do
+      writedata[i] := random(256);
+    stream.WriteBuffer(writedata[0], Length(writedata));
+  finally
+    stream.Free;
+  end;
+
+  // Use a TBufStream to read parts of the file back
+  stream := TBufStream.Create(tempFilename, fmOpenRead, BUF_SIZE);
+  try
+    // Check stream size
+    CheckEquals(FILE_SIZE, stream.Size, 'Size mismatch');
+
+    // Read first 100 bytes and compare with data
+    nread := 100;
+    SetLength(readdata, nread);
+    n := stream.Read(readdata[0], nread);
+    CheckEquals(nread, n, 'Bytes count mismatch');
+    for i:=0 to nread-1 do
+      CheckEquals(writedata[i], readdata[i], Format('Read mismatch at position %d', [i]));
+
+    // Check stream size
+    CheckEquals(FILE_SIZE, stream.Size, 'Size mismatch');
+
+    // Read next 100 bytes and compare
+    stream.ReadBuffer(readdata[0], nread);
+    for i:=0 to nread-1 do
+      CheckEquals(writedata[i+nread], readdata[i], Format('Read mismatch at position %d', [i+nread]));
+
+    // Go to position 1000, this is 24 bytes to the end of the buffer, and read
+    // 100 bytes again - this process will require to refresh the buffer
+    stream.Position := 1000;
+    stream.ReadBuffer(readdata[0], nread);
+    for i:=0 to nread-1 do
+      CheckEquals(writedata[i+1000], readdata[i], Format('Read mismatch at position %d', [i+1000]));
+
+    // Check stream size
+    CheckEquals(FILE_SIZE, stream.Size, 'Size mismatch');
+
+    // Read next 100 bytes
+    stream.ReadBuffer(readdata[0], nread);
+    for i:=0 to nread-1 do
+      CheckEquals(writedata[i+1000+nread], readdata[i], Format('Read mismatch at position %d', [i+1000+nread]));
+
+    // Go back to start and fill the memory stream again with bytes 0..1023
+    stream.Position := 0;
+    stream.ReadBuffer(readdata[0], nread);
+
+    // Now read 100 bytes which are not in the buffer
+    stream.Position := 1500;  // this is past the buffered range
+    stream.ReadBuffer(readdata[0], 100);
+    for i:=0 to nread-1 do
+      CheckEquals(writedata[i+1500], readdata[i], Format('Read mismatch at position %d', [i+1500]));
+
+    // Go back to start and fill the memory stream again with bytes 0..1023
+    stream.Position := 0;
+    stream.ReadBuffer(readdata[0], 100);
+
+    // Read last 100 bytes
+    stream.Seek(nread, soFromEnd);
+    stream.ReadBuffer(readdata[0], nread);
+    for i:=0 to nread-1 do
+      CheckEquals(writedata[i+FILE_SIZE-nread], readdata[i],
+        Format('Read mismatch at position %d', [i+FILE_SIZE-nread]));
+
+  finally
+    stream.Free;
+    DeleteFile(tempFileName);
+  end;
+end;
+
 procedure TSpreadInternalTests.TestCellString;
 var
   r,c: Cardinal;
@@ -307,9 +397,9 @@ begin
   workbook := TsWorkbook.Create;
   try
     worksheet := workbook.AddWorksheet('VirtualMode');
-    workbook.WritingOptions := workbook.WritingOptions + [woVirtualMode];
+    workbook.Options := workbook.Options + [boVirtualMode];
     if ABufStreamMode then
-      workbook.WritingOptions := workbook.WritingOptions + [woBufStream];
+      workbook.Options := workbook.Options + [boBufStream];
     workbook.VirtualColCount := 1;
     workbook.VirtualRowCount := Length(SollNumbers) + 4;
     // We'll use only the first 4 SollStrings, the others cause trouble due to utf8 and formatting.

components/fpspreadsheet/xlsbiff2.pas

@@ -1084,7 +1084,7 @@ begin
     WriteColWidths(AStream);
     WriteRows(AStream, sheet);
 
-    if (woVirtualMode in Workbook.WritingOptions) then
+    if (boVirtualMode in Workbook.Options) then
       WriteVirtualCells(AStream)
     else begin
       WriteRows(AStream, sheet);

components/fpspreadsheet/xlsbiff5.pas

@@ -347,7 +347,7 @@ var
   OutputStorage: TOLEStorage;
   OLEDocument: TOLEDocument;
 begin
-  if (woBufStream in Workbook.WritingOptions) then begin
+  if (boBufStream in Workbook.Options) then begin
     Stream := TBufStream.Create
   end else
     Stream := TMemoryStream.Create;
@@ -434,7 +434,7 @@ begin
       WriteSelection(AStream, sheet, pane);
       WriteRows(AStream, sheet);
 
-      if (woVirtualMode in Workbook.WritingOptions) then
+      if (boVirtualMode in Workbook.Options) then
         WriteVirtualCells(AStream)
       else begin
         WriteRows(AStream, sheet);

components/fpspreadsheet/xlsbiff8.pas

@@ -365,7 +365,7 @@ var
   OutputStorage: TOLEStorage;
   OLEDocument: TOLEDocument;
 begin
-  if (woBufStream in Workbook.WritingOptions) then begin
+  if (boBufStream in Workbook.Options) then begin
     Stream := TBufStream.Create
   end else
     Stream := TMemoryStream.Create;
@@ -446,7 +446,7 @@ begin
       WriteDimensions(AStream, sheet);
       //WriteRowAndCellBlock(AStream, sheet);
 
-      if (woVirtualMode in Workbook.WritingOptions) then
+      if (boVirtualMode in Workbook.Options) then
         WriteVirtualCells(AStream)
       else begin
         WriteRows(AStream, sheet);

components/fpspreadsheet/xlsxooxml.pas

@@ -880,7 +880,7 @@ begin
   h0 := Workbook.GetDefaultFontSize;  // Point size of default font
 
   // Create the stream
-  if (woBufStream in Workbook.WritingOptions) then
+  if (boBufStream in Workbook.Options) then
     FSSheets[FCurSheetNum] := TBufStream.Create(GetTempFileName('', Format('fpsSH%d', [FCurSheetNum])))
   else
     FSSheets[FCurSheetNum] := TMemoryStream.Create;
@@ -902,7 +902,7 @@ begin
   AppendToStream(FSSheets[FCurSheetNum],
       '<sheetData>');
 
-  if (woVirtualMode in Workbook.WritingOptions) and Assigned(Workbook.OnNeedCellData)
+  if (boVirtualMode in Workbook.Options) and Assigned(Workbook.OnNeedCellData)
   then begin
     for r := 0 to Workbook.VirtualRowCount-1 do begin
       row := CurSheet.FindRow(r);
@@ -1012,7 +1012,7 @@ end;
   single xlsx file. }
 procedure TsSpreadOOXMLWriter.CreateStreams;
 begin
-  if (woBufStream in Workbook.WritingOptions) then begin
+  if (boBufStream in Workbook.Options) then begin
     FSContentTypes := TBufStream.Create(GetTempFileName('', 'fpsCT'));
     FSRelsRels := TBufStream.Create(GetTempFileName('', 'fpsRR'));
     FSWorkbookRels := TBufStream.Create(GetTempFileName('', 'fpsWBR'));
@@ -1111,7 +1111,7 @@ begin
     then lMode := fmCreate or fmOpenWrite
     else lMode := fmCreate;
 
-  if (woBufStream in Workbook.WritingOptions) then
+  if (boBufStream in Workbook.Options) then
     lStream := TBufStream.Create(AFileName, lMode)
   else
     lStream := TFileStream.Create(AFileName, lMode);