Question

我正在做两个函数来加入和分割TFileStream中的文件，代码：

加入

procedure TFormHome.btnJoinClick(Sender: TObject);
var
  InStream, OutStream: TFileStream;
  OutFileName, InFileName1, InFileName2: string;
begin
  OutFileName := 'salida.out';
  InFileName1 := 'image.jpg';
  InFileName2 := 'test.exe';
  OutStream := TFileStream.Create(OutFileName, fmCreate);
  try
    InStream := TFileStream.Create(InFileName1, fmOpenRead);
    ShowMessage(IntToStr(InStream.Size));
    try
      OutStream.CopyFrom(InStream, InStream.Size);
    finally
      InStream.Free;
    end;
    InStream := TFileStream.Create(InFileName2, fmOpenRead);
    ShowMessage(IntToStr(InStream.Size));
    try
      OutStream.CopyFrom(InStream, InStream.Size);
    finally
      InStream.Free;
    end;
  finally
    OutStream.Free;
  end;
end;

鸿沟

procedure TFormHome.btnUnJoinClick(Sender: TObject);
var
  Source, Target: TStream;
  Buffer: array of Byte;
  i: Integer;
  SourceName, TargetNames: string;
  SizeTargets: Integer;
begin
  SourceName := 'salida.out';
  TargetNames := 'test.exe';
  SizeTargets := 2232832;
  Source := TFileStream.Create(SourceName, fmOpenRead);
  Target := TFileStream.Create(TargetNames, fmCreate);
  try
    SetLength(Buffer, SizeTargets);
    Source.ReadBuffer(Pointer(Buffer)^, Length(Buffer));
    Target.WriteBuffer(Buffer[0], Length(Buffer));
  finally
    Target.Free;
  end;
end;

问题在于，当我分割文件时，可执行文件在我想显示错误时会中断并运行：

  Windows can not find the file "route ..." Make sure the name is spelled correctly and try again

或

  The version of this file is not compatible with the version of Windows you are running ... (and then talking about 32 or 64 bits)

同时检查第二个函数中可执行文件的大小是否正常。

问题在于，在第二个代码中，所有文件都被破坏了

如何解决这个问题？

Answer 1

您正在连接多个输入文件，而不在输出中指示一个文件结束而下一个文件开始。您的除法码不知道哪些字节属于JPG，哪些字节属于EXE。

例如，您显示的除法代码是提取JPG字节并将其保存到.exe文件。当然，.exe文件无法正常运行。

为了提取EXE，您必须首先提取/跳过JPG，这意味着您必须知道JPG中有多少字节。因此，您需要将输入文件大小存储在连接的输出中，而不仅仅是它们的数据，例如：

procedure TFormHome.btnJoinClick(Sender: TObject);
var
  OutStream: TFileStream;

  procedure AddFile(const FileName: sstring);
  var
    InStream: TStream;
    Size: Int64;
  begin
    InStream := TFileStream.Create(FileName, fmOpenRead or fmShareDenyWrite);
    try
      Size := InStream.Size;
      OutStream.WriteBuffer(Size, SizeOf(Size));
      OutStream.CopyFrom(InStream, Size);
    finally
      InStream.Free;
    end;
  end;

begin
  OutStream := TFileStream.Create('salida.out', fmCreate);
  try
    AddFile('image.jpg');
    AddFile('test.exe');
  finally
    OutStream.Free;
  end;
end;

procedure TFormHome.btnUnJoinClick(Sender: TObject);
var
  Source: TStream;

  procedure SkipFile;
  var
    Size: Int64;
  begin
    Source.ReadBuffer(Size, SizeOf(Size));
    Source.Seek(Size, soCurrent);
  end;

  procedure ExtractFile(const FileName: string);
  var
    Target: TStream;
    Size: Int64;
  begin
    Source.ReadBuffer(Size, SizeOf(Size));

    Target := TFileStream.Create(FileName, fmCreate);
    try
      Target.CopyFrom(Source, Size);
    finally
      Target.Free;
    end;
  end;

begin
  Source := TFileStream.Create('salida.out', fmOpenRead or fmShareDenyWrite);
  try
    SkipFile;
    ExtractFile('test.exe');
  finally
    Source.Free;
  end;
end;

我建议您考虑存储文件名：

procedure TFormHome.btnJoinClick(Sender: TObject);
var
  OutStream: TFileStream;

  procedure AddFile(const FileName: string);
  var
    InStream: TStream;
    Name: UTF8String;
    Len: Integer;
    FileSize, TotalSize: Int64;
  begin
    InStream := TFileStream.Create(FileName, fmOpenRead or fmShareDenyWrite);
    try
      Name := UTF8String(ExtractFileName(FileName));
      Len := Length(Name);

      FileSize := InStream.Size;

      TotalSize := SizeOf(Len) + Len + SizeOf(FileSize) + FileSize;
      OutStream.WriteBuffer(TotalSize, SizeOf(TotalSize));

      OutStream.WriteBuffer(Len, SizeOf(Len));
      OutStream.WriteBuffer(PAnsiChar(Name)^, Len);
      OutStream.WriteBuffer(FileSize, SizeOf(FileSize));
      OutStream.CopyFrom(InStream, FileSize);
    finally
      InStream.Free;
    end;
  end;

begin
  OutStream := TFileStream.Create('salida.out', fmCreate);
  try
    AddFile('image.jpg');
    AddFile('test.exe');
  finally
    OutStream.Free;
  end;
end;

procedure TFormHome.btnUnJoinClick(Sender: TObject);
var
  Source: TStream;

  procedure SkipFile;
  var
    TotalSize: Int64;
  begin
    Source.ReadBuffer(TotalSize, SizeOf(TotalSize));
    Source.Seek(TotalSize, soCurrent);
  end;

  procedure ExtractFile;
  var
    Target: TStream;
    TotalSize, FileSize: Int64;
    Name: UTF8String;
    Len: Integer;
    Pos: Int64;
  begin
    Source.ReadBuffer(TotalSize, SizeOf(TotalSize));
    Pos := Source.Position;

    Source.ReadBuffer(Len, SizeOf(Len));
    SetLength(Name, Len);
    Source.ReadBuffer(PAnsiChar(Name)^, Len);

    Source.ReadBuffer(FileSize, SizeOf(FileSize));

    Target := TFileStream.Create(String(Name), fmCreate);
    try
      Target.CopyFrom(Source, FileSize);
    finally
      Target.Free;
    end;

    if (Source.Position - Pos) <> TotalSize then
      raise Exception.Create('Extract failed. Bad position');
  end;

begin
  Source := TFileStream.Create('salida.out', fmOpenRead or fmShareDenyWrite);
  try
    SkipFile;
    ExtractFile;
  finally
    Source.Free;
  end;
end;

将文件拆分为TFileStream

1 个答案: