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function EncodeBase64(const inStr: string): string;

  function Encode_Byte(b: Byte): char;

  const

    Base64Code: string[64] =

      'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

  begin

    Result := Base64Code[(b and $3F)+1];

  end;

var

  i: Integer;

begin

  i := 1;

  Result := '';

  while i < =Length(InStr) do

  begin

    Result := Result + Encode_Byte(Byte(inStr[i]) shr 2);

    Result := Result + Encode_Byte((Byte(inStr[i]) shl 4) or (Byte(inStr[i+1]) shr 4));

    if i+1 < =Length(inStr) then

      Result := Result + Encode_Byte((Byte(inStr[i+1]) shl 2) or (Byte(inStr[i+2]) shr 6))

    else

      Result := Result + '=';

    if i+2 < =Length(inStr) then

      Result := Result + Encode_Byte(Byte(inStr[i+2]))

    else

      Result := Result + '=';

    Inc(i, 3);

  end;

end;

// Base64 decoding

function DecodeBase64(const CinLine: string): string;

const

  RESULT_ERROR = -2;

var

  inLineIndex: Integer;

  c: Char;

  x: SmallInt;

  c4: Word;

  StoredC4: array[0..3] of SmallInt;

  InLineLength: Integer;

begin

  Result := '';

  inLineIndex := 1;

  c4 := 0;

  InLineLength := Length(CinLine);

  while inLineIndex < =InLineLength do

  begin

    while (inLineIndex < =InLineLength) and (c4 < 4) do

    begin

      c := CinLine[inLineIndex];

      case c of

        '+'     : x := 62;

        '/'     : x := 63;

        '0'..'9': x := Ord(c) - (Ord('0')-52);

        '='     : x := -1;

        'A'..'Z': x := Ord(c) - Ord('A');

        'a'..'z': x := Ord(c) - (Ord('a')-26);

      else

        x := RESULT_ERROR;

      end;

      if x < > RESULT_ERROR then

      begin

        StoredC4[c4] := x;

        Inc(c4);

      end;

      Inc(inLineIndex);

    end;

    if c4 = 4 then

    begin

      c4 := 0;

      Result := Result + Char((StoredC4[0] shl 2) or (StoredC4[1] shr 4));

      if StoredC4[2] = -1 then Exit;

      Result := Result + Char((StoredC4[1] shl 4) or (StoredC4[2] shr 2));

      if StoredC4[3] = -1 then Exit;

      Result := Result + Char((StoredC4[2] shl 6) or (StoredC4[3]));

    end;

  end;

end;