How to convert string with trailing zero to AnsiString?

Question

I have code that compiles fine with D7, but not with D2010. Obviously this is a Unicode problem:

Compilation error: E2251 Ambiguous overloaded call 'StrPas'

Here is the whole procedure:

procedure GetVersionInfo;
type
  PLangCharSetInfo = ^TLangCharSetInfo;
  TLangCharSetInfo = record
    Lang: Word;
    CharSet: Word;
  end;
var
  FileName: array [0..260] of Char;
  SubBlock: array [0..255] of Char;
  VerHandle: Cardinal;
  Size: Word;
  Buffer: Pointer;
  Data: Pointer;
  DataLen: LongWord;
  LangCharSetInfo: PLangCharSetInfo;
  LangCharSetString: string;
begin
  LabelComments.Caption := 'No version information for this program is available!';
  {Get size and allocate buffer for VerInfo}
  if GetModuleFileName(hInstance, FileName, SizeOf(FileName)) > 0 then
  begin
    Size := GetFileVersionInfoSize(FileName, VerHandle);
    if Size > 0 then
    begin
      GetMem(Buffer, Size);
      try
        if GetFileVersionInfo(FileName, VerHandle, Size, Buffer) then
        begin
          {Query first language and that language blocks version info}
          if VerQueryValue(Buffer, '\VarFileInfo\Translation', Pointer(LangCharSetInfo), DataLen) then
          begin
            LangCharSetString := IntToHex(LangCharSetInfo^.Lang, 4) +
                                 IntToHex(LangCharSetInfo^.CharSet, 4);
            if VerQueryValue(Buffer, StrPCopy(SubBlock, '\StringFileInfo\' + LangCharSetString + '\ProductName'), Data, DataLen) then
            begin
              LabelProductName.Caption := StrPas(Data);
              Caption := LabelProductName.Caption;
            end;
            if VerQueryValue(Buffer, StrPCopy(SubBlock, '\StringFileInfo\' + LangCharSetString + '\FileVersion'), Data, DataLen) then
              LabelVersion.Caption := StrPas(Data);
            if VerQueryValue(Buffer, StrPCopy(SubBlock, '\StringFileInfo\' + LangCharSetString + '\LegalCopyright'), Data, DataLen) then
              LabelCopyright.Caption := StrPas(Data);
            if VerQueryValue(Buffer, StrPCopy(SubBlock, '\StringFileInfo\' + LangCharSetString + '\Comments'), Data, DataLen) then
              LabelComments.Caption := StrPas(Data);
          end;
        end;
      finally
        FreeMem(Buffer, Size);
      end;
    end
  end;
end;

Doc for StrPas says

function StrPas(const Str: PAnsiChar): AnsiString; overload;

This feature is provided only for backward compatibility with fasor. To convert a terminating null string to AnsiString or native Delphi language string, use a type or sign.

So the question is, should all calls in StrPas be deleted? The only way to do this for compilation is to make a hardcast for the PAnsi char, for example:

LabelProductName.Caption := StrPas(PAnsiChar(Data));

Answer 1

. !

, , , JCL ( ). TJclFileVersionInfo, , , , VersionInfo.

- :

function GetStringFileInfo(
  const Buffer: Pointer; const SubBlock: PChar;
  const LangCharSetString: string; const Kind: string): string;
var
  QueryString: string;
  Data: Pointer;
  DataCharacters: PChar absolute Data;
  DataLen: LongWord;
begin
  Result := '';
  QueryString := Format('%s\StringFileInfo\%s\%s', [SubBlock, LangCharSetString, Kind]);
  if VerQueryValue(Buffer, PChar(QueryString), Data, DataLen) then
    Result := StrPas(DataCharacters);
end;

procedure GetVersionInfoStrings(var Comments: string; var ProductName: string;
  var Caption: string; var Version: string; var Copyright: string);
type
  PLangCharSetInfo = ^TLangCharSetInfo;
  TLangCharSetInfo = record
    Lang: Word;
    CharSet: Word;
  end;
var
  FileName: array [0 .. 260] of Char;
  SubBlock: array [0 .. 255] of Char;
  VerHandle: Cardinal;
  Size: Word;
  Buffer: Pointer;
  Data: Pointer;
  DataCharacters: PChar absolute Data;
  DataLen: LongWord;
  LangCharSetInfo: PLangCharSetInfo;
  LangCharSetString: string;
begin
  Comments := 'No version information for this program is available!';
  { Get size and allocate buffer for VerInfo }
  if GetModuleFileName(hInstance, FileName, SizeOf(FileName)) > 0 then
  begin
    Size := GetFileVersionInfoSize(FileName, VerHandle);
    if Size > 0 then
    begin
      GetMem(Buffer, Size);
      try
        if GetFileVersionInfo(FileName, VerHandle, Size, Buffer) then
        begin
          { Query first language and that language blocks version info }
          if VerQueryValue(Buffer, '\VarFileInfo\Translation', Pointer
              (LangCharSetInfo), DataLen) then
          begin
            LangCharSetString :=
              IntToHex(LangCharSetInfo^.Lang, 4) +
              IntToHex(LangCharSetInfo^.CharSet, 4);
            ProductName := GetStringFileInfo(Buffer, SubBlock, LangCharSetString, 'ProductName');
            Version := GetStringFileInfo(Buffer, SubBlock, LangCharSetString, 'FileVersion');
            Copyright := GetStringFileInfo(Buffer, SubBlock, LangCharSetString, 'LegalCopyright');
            Comments := GetStringFileInfo(Buffer, SubBlock, LangCharSetString, 'Comments');
            Caption := ProductName;
          end;
        end;
      finally
        FreeMem(Buffer, Size);
      end;
    end
  end;
end;

- .

-

:

, .

Buffer, SubBlock, LongCharSetString DataLen? Buffer?

(Ansi Unicode)? PVSFixedFileInfo?

(: - ? -, , , , . ).

, , JCL JVCL. Unicode.

, VerQueryValue, JclFileUtils, VersionFixedFileInfo:

// Fixed Version Info routines
function VersionFixedFileInfo(const FileName: string; var FixedInfo: TVSFixedFileInfo): Boolean;
var
  Size, FixInfoLen: DWORD;
  Handle: THandle;
  Buffer: string;
  FixInfoBuf: PVSFixedFileInfo;
begin
  Result := False;
  Size := GetFileVersionInfoSize(PChar(FileName), Handle);
  if Size > 0 then
  begin
    SetLength(Buffer, Size);
    if GetFileVersionInfo(PChar(FileName), Handle, Size, Pointer(Buffer)) and
      VerQueryValue(Pointer(Buffer), DirDelimiter, Pointer(FixInfoBuf), FixInfoLen) and
      (FixInfoLen = SizeOf(TVSFixedFileInfo)) then
    begin
      Result := True;
      FixedInfo := FixInfoBuf^;
    end;
  end;
end;

, .

-

Answer 2

StrPas Delphi 1, Delphi, . .: http://coding.derkeiler.com/Archive/Delphi/borland.public.delphi.language.objectpascal/2004-01/1793.html

:

LabelProductName.Caption := PAnsiChar(Data);

, StrPas. , D2010.

Answer 3

, , Data Pointer, PChar.

, , , , , .

. PChar PAnsiChar, String. , , , Pointer.

Answer 4

Convert PAnsiChar to AnsiString and then to Unicode string:

LabelProductName.Caption := String(AnsiString(PAnsiChar(Data)));