TEncoding (Delphi)

Description

This example determines the encoding of a source file and then writes the file in any encoding chosen. Use this project to create files of any encoding. This example requires two text edits and a combo box.

Code

procedure TForm1.Button1Click(Sender: TObject);
var
  LBuffer: TBytes;
  LByteOrderMark: TBytes;
  LOffset: Integer;
  LEncoding, DestEncoding: TEncoding;
  LFileStream: TFileStream;
  EncodingArray: array[0..5] of TEncoding;
begin
  LEncoding:= nil;
  EncodingArray[0]:= TEncoding.UTF8;
  EncodingArray[1]:= TEncoding.UTF7;
  EncodingArray[2]:= TEncoding.Unicode;
  EncodingArray[3]:= TEncoding.Default;
  EncodingArray[4]:= TEncoding.BigEndianUnicode;
  EncodingArray[5]:= TEncoding.ASCII;
  DestEncoding := EncodingArray[ComboBox1.ItemIndex];
  LFileStream := TFileStream.Create(Edit1.Text, fmOpenRead);
  try
    // Read file into buffer.
    SetLength(LBuffer, LFileStream.Size);
//    LFileStream.Read(LBuffer[0], Length(LBuffer));
    LFileStream.ReadBuffer(Pointer(LBuffer)^, Length(LBuffer));

    // Identify encoding and convert buffer to UTF8.
    LOffset := TEncoding.GetBufferEncoding(LBuffer, LEncoding);
//    for I := 0 to Length(LBuffer) - 1 do
//      Memo1.Lines.Add((LBuffer[I]));
    LBuffer := LEncoding.Convert(LEncoding, DestEncoding, LBuffer,
      LOffset, Length(LBuffer) - LOffset);
  finally
    LFileStream.Free;
  end;

  LFileStream := TFileStream.Create(Edit2.Text, fmCreate);
  try
    // Write an encoding byte-order mark and buffer to output file.
    LByteOrderMark := DestEncoding.GetPreamble;
    LFileStream.Write(LByteOrderMark[0], Length(LByteOrderMark));
    LFileStream.Write(LBuffer[0], Length(LBuffer));
  finally
    LFileStream.Free;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
   with ComboBox1, Items do begin
     Add('TEncoding.UTF8');
     Add('TEncoding.UTF7');
     Add('TEncoding.Unicode');
     Add('TEncoding.Default');
     Add('TEncoding.BigEndianUnicode');
     Add('TEncoding.ASCII');
     ItemIndex := 0;
  end;
end;

Uses

• System.SysUtils.TEncoding ( fr | de | ja )
• System.SetLength ( fr | de | ja )
• System.Classes.TStream.Size ( fr | de | ja )
• System.Classes.THandleStream.Read ( fr | de | ja )
• System.Classes.THandleStream.Write ( fr | de | ja )
• System.Classes.TStream.ReadBuffer ( fr | de | ja )