fpspreadsheet: Improved file format detection

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@3905 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/fpspreadsheet/fpspreadsheet.pas

@@ -964,7 +964,7 @@ implementation
 
 uses
   Math, StrUtils, TypInfo, lazutf8,
-  fpsPatches, fpsStrings, fpsStreams,
+  fpsPatches, fpsStrings, fpsStreams, uvirtuallayer_ole,
   fpsUtils, fpsCurrency, fpsNumFormatParser, fpsExprParser;
 
 const
@@ -6434,18 +6434,27 @@ const
     $09,$00, $04,$00, $00,$00, $10,$00, $31,$00, $0A,$00, $C8,$00, $00,$00);
   BIFF58_HEADER: array[0..7] of byte = (
     $D0,$CF, $11,$E0, $A1,$B1, $1A,$E1);
-  BIFF5_MARKER: array[0..7] of widechar = (
+
-    'B', 'o', 'o', 'k', #0, #0, #0, #0);
+  function ValidOLEStream(AStream: TStream; AName: String): Boolean;
-  BIFF8_MARKER:array[0..7] of widechar = (
+  var
-    'W', 'o', 'r', 'k', 'b', 'o', 'o', 'k');
+    fsOLE: TVirtualLayer_OLE;
+  begin
+    AStream.Position := 0;
+    fsOLE := TVirtualLayer_OLE.Create(AStream);
+    try
+      fsOLE.Initialize;
+      Result := fsOLE.FileExists('/'+AName);
+    finally
+      fsOLE.Free;
+    end;
+  end;
+
 var
-  buf: packed array[0..16] of byte;
+  buf: packed array[0..16] of byte = (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
   stream: TStream;
   i: Integer;
   ok: Boolean;
 begin
-  buf[0] := 0;  // Silence the compiler...
-
   Result := false;
   stream := TFileStream.Create(AFileName, fmOpenRead + fmShareDenyNone);
   try
@@ -6471,28 +6480,20 @@ begin
       if buf[i] <> BIFF58_HEADER[i] then
         exit;
 
-    // Further information begins at offset $480:
+    // Now we know that the file is a Microsoft compound document.
-    stream.Position := $480;
+
-    stream.ReadBuffer(buf, 16);
+    // We check for Excel 5 in which the stream is named "Book"
-    // Check for Excel5
+    if ValidOLEStream(stream, 'Book') then begin
-    ok := true;
-    for i:=0 to 7 do
-      if WideChar(buf[i*2]) <> BIFF5_MARKER[i] then
-      begin
-        ok := false;
-        break;
-      end;
-    if ok then
-    begin
       SheetType := sfExcel5;
-      Exit(True);
+      exit(True);
     end;
-    // Check for Excel8
+
-    for i:=0 to 7 do
+    // Now we check for Excel 8 which names the stream "Workbook"
-      if WideChar(buf[i*2]) <> BIFF8_MARKER[i] then
+    if ValidOLEStream(stream, 'Workbook') then begin
-        exit(false);
+      SheetType := sfExcel8;
-    SheetType := sfExcel8;
+      exit(True);
-    Exit(True);
+    end;
+
   finally
     stream.Free;
   end;
@@ -8447,17 +8448,10 @@ procedure TsCustomSpreadReader.ReadFromFile(AFileName: string; AData: TsWorkbook
 var
   InputFile: TStream;
 begin
-
   if (boBufStream in Workbook.Options) then
     InputFile := TBufStream.Create(AFileName, fmOpenRead + fmShareDenyNone)
   else
     InputFile := TFileStream.Create(AFileName, fmOpenRead + fmShareDenyNone);
-  {
-  //<--
-  InputFile := TMemoryStream.Create;
-  TMemoryStream(InputFile).LoadFromFile(AFilename);
-  //--->
-   }
 
   try
     ReadFromStream(InputFile, AData);

components/fpspreadsheet/uvirtuallayer.pas

@@ -27,6 +27,7 @@ type
     function FindMounted(const APath: UTF8String): TVirtualLayer; overload;
     function PreviousPath(const APath: UTF8String): UTF8String;
     function StripMountPoints(const APath: UTF8String): UTF8String;
+
   protected
     FParentLayer: TVirtualLayer;
     FVirtualLayerStream: TStream;
@@ -59,8 +60,8 @@ type
 
     procedure Lock(); virtual;
     procedure Unlock(); virtual;
-  public
 
+  public
     function MakeFolder(const AFolder: UTF8String): Boolean;
     function RemoveFolder(const AFolder: UTF8String): Boolean;
     function DeleteFile(const AFileName: UTF8String): Boolean;
@@ -100,11 +101,11 @@ type
 implementation
 
 type
-TFileRecLocal=record
+  TFileRecLocal = record
-  FL: TVirtualLayer_FolderList;
+    FL: TVirtualLayer_FolderList;
-  Attr: LongInt;
+    Attr: LongInt;
-end;
+  end;
-PFileRecLocal=^TFileRecLocal;
+  PFileRecLocal=^TFileRecLocal;
 
 { TVirtualLayer }