write_file.ps

%!PS-Adobe-3.0 EPSF-3.0
%%Pages: 1
%%BoundingBox:   0 0 1000 1000
%%LanguageLevel: 1
%%EndComments
%%BeginProlog
%%EndProlog

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%                                      %
%  RedTeam Pentesting GmbH             %
%  kontakt@redteam-pentesting.de       %
%  https://www.redteam-pentesting.de/  %
%                                      %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%% Page Setup
/charactercount 100 def

% white page
1 1 1 setrgbcolor clippath fill
% black text
0 0 0 setrgbcolor
/pagewidth currentpagedevice /PageSize get 0 get def
/pageheight currentpagedevice /PageSize get 1 get def

% calculate the character width
/characterWidth pagewidth charactercount div def

/Courier findfont setfont

/curWidth (-) stringwidth pop def

/Courier findfont characterWidth curWidth div scalefont setfont

/lineheight characterWidth curWidth div def

% initial x and y positions
/xposinit 10 def
/yposinit pageheight lineheight sub def

/xpos xposinit def
/ypos yposinit def
xpos ypos moveto



%%%%%%%%%%%%%%%%%%% Base64 Encoding Code
% http://www.sunshine2k.de/articles/coding/base64/understanding_base64.html
/base64DecodingTable [
    80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 %/* 0 - 15 */
    80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 %/* 16 - 31 */
    80 80 80 80 80 80 80 80 80 80 80 62 80 80 80 63 %/* 32 - 47 */
    52 53 54 55 56 57 58 59 60 61 80 80 80 64 80 80 %/* 48 - 63 */
    80  0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 %/* 64 - 79 */
    15 16 17 18 19 20 21 22 23 24 25 80 80 80 80 80 %/* 80 - 96 */
    80 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 %/* 87 - 111 */
    41 42 43 44 45 46 47 48 49 50 51 80 80 80 80 80 %/* 112 - 127 */
] def


% takes 4 base64-encoded chars and returns their 3 byte values
% inputChars FourCharsToThreeBytes outputBytes
/FourCharsToThreeBytes {
    /inputChars exch def
    /c1 base64DecodingTable inputChars 0 get get def
    /c2 base64DecodingTable inputChars 1 get get def
    /c3 base64DecodingTable inputChars 2 get get def
    /c4 base64DecodingTable inputChars 3 get get def

    /b1
        c1 2#00111111 and 2 bitshift
        c2 2#00110000 and -4 bitshift
        xor
    def
    % handle padding chars
    c3 64 eq c4 64 eq and {
        b1
    } {
        /b2
            c2 2#00001111 and 4 bitshift
            c3 2#00111100 and -2 bitshift
            xor
        def

        c4 64 eq {
            b1 b2
        } {
            /b3
                c3 2#00000011 and 6 bitshift
                c4 2#00111111 and
                xor
            def
            b1 b2 b3
        } ifelse
    } ifelse
} def

% Decodes a Base64-encoded String to bytes
% base64InputString base64Decode byteArray
/base64Decode {
    /inputString exch def
    [
    0 4 inputString length 1 sub {
        /i exch def

        [inputString i 4 getinterval {} forall] FourCharsToThreeBytes
    } for
    ]
} def

%%%%%%%%%%%%%%%%%%% Printing Code
% Move to new line and go to next page if current page is full
% lineheight newline -
/newline {
    /lineheight exch def

    % new page if we are at the bottom of the page
    ypos lineheight lt {
        showpage
        /xpos xposinit def
        /ypos yposinit def
        xpos ypos moveto
    } if

    % decrease y position
    ypos lineheight sub
    /ypos exch def

    % move cursor
    xpos ypos moveto
} def

%%%%%%%%%%%%%%%%%%% Actual Code
{
    /outfile (/tmp/testfile.txt) (w) file def

    %%%WRITING PLAINTEXT:
    % outfile (Output string which will be written to outfile) writestring

    %%%DECODE BASE64 AND WRITE:
    (SGFsbG8gV2VsdAo=) base64Decode { outfile exch write } forall
    outfile closefile
} stopped {
    % if an error occurs, the cause is printed
    /errormessage {
        $error /errorname get 50 string cvs
    } def
    (printing file failed : ) show
    lineheight newline
    errormessage show
} {
    (Writing file successful!) show
} ifelse % error catching frame

showpage