path: root/gs/lib/pdfwrite.ps

%    Copyright (C) 1999, 2000, 2001 Aladdin Enterprises.  All rights reserved.
%
% This software is provided AS-IS with no warranty, either express or
% implied.
%
% This software is distributed under license and may not be copied,
% modified or distributed except as expressly authorized under the terms
% of the license contained in the file LICENSE in this distribution.
%
% For more information about licensing, please refer to
% http://www.ghostscript.com/licensing/. For information on
% commercial licensing, go to http://www.artifex.com/licensing/ or
% contact Artifex Software, Inc., 101 Lucas Valley Road #110,
% San Rafael, CA  94903, U.S.A., +1(415)492-9861.

% $Id$
% Writer for transmuting PDF files.

% NOTES:
% We do editing by replacing objects (in the cache) and then doing a
%   simple recursive walk with object renumbering.
% Free variables:
%   RMap [per input file] (dict): input_obj# => output_obj#
%   PDFfile (file): current input file
%   OFile (file): current output file
%   XRef (dict): output_obj# => output_file_pos
%   ToWrite: 0..N-1 => [obj# gen#]

.languagelevel 2 .setlanguagelevel
.currentglobal true .setglobal

/PDFWRDEBUG where { pop } { /PDFWRDEBUG false def } ifelse

% ======== Long dictionary support =============== %

% The key must be a non-negative iteger.

/ld_dict {          % <len> ld_dict <ldict>
  pop << 0 <<>> >>
} bind def

/ld_length {        % <ldict> ld_length <length>
  0 exch { exch pop length add } forall
} bind def

/ld_get {           % <ldict> <key> ld_get <any>
  dup 3 1 roll -15 bitshift get exch get
} bind def

/ld_put {           % <ldict> <key> <any> ld_put -
  3 1 roll dup               % any ldict key key
  4 1 roll -15 bitshift      % key any ldict key>>15
  2 copy known {
    get                      % key any subdict
    3 1 roll put             % -
  } {
    64 dict dup 6 1 roll     % <<>> key any ldict key>>15 <<>>
    put put
  } ifelse                   % -
} bind def

/ld_known {         % <ldict> <key> ld_known <bool>
  dup 3 1 roll -15 bitshift  % key <<>> key<<15
  2 copy known {
    get exch known
  } {
    pop pop pop //false
  } ifelse
} bind def

/ld_knownget {      % <ldict> <key> ld_known false | <any> true
  dup 3 1 roll -15 bitshift  % key <<>> key<<15
  2 copy known {
    get exch .knownget
  } {
    pop pop pop //false
  } ifelse
} bind def

/ld_def {           % <key> <any> ld_def -
  currentdict 3 1 roll ld_put
} bind def

/ld_forall {        % <ldict> <proc} ld_forall -
  { forall exch pop } aload pop
  4 2 roll 4 packedarray cvx forall
} bind def

/ld_clone {         % <ldict> ld_clone <ldict copy>
  << exch { dup length dict copy } forall >>
} bind def

% ================ Object mapping ================ %

% Initialize the object number and location map.
/omapinit {		% - omapinit -
  /RMap 100 ld_dict def
  /XRef 100 ld_dict def
  PDFWRDEBUG { (omapinit) = } if
} bind def

% Map an object number.
/omapnew {		% <oldobj#> omap <newobj#> <isnew>
  RMap 1 index ld_knownget {
    exch pop //false
  } {
    PDFWRDEBUG { (omap\() print dup =only } if
    RMap dup ld_length 1 add   % old# <<>> len+1
    2 index exch dup           % old# <<>> old# len+1 len+1
    5 1 roll                   % len+1 old# <<>> old# len+1
    ld_put pop //true          % len+1 true
    PDFWRDEBUG { (\) = ) print 1 index = } if
  } ifelse
} bind def
/omap {			% <oldobj#> omap <newobj#>
  omapnew pop
} bind def

% Save and restore the object map.
% Note that currentomap either returns a copy or calls omapinit.
/currentomap {		% <copy> currentomap <omap>
  {
    [RMap ld_clone XRef ld_clone]
  } {
    [RMap XRef] omapinit
  } ifelse
} bind def
/setomap {		% <omap> setomap -
  aload pop /XRef exch def /RMap exch def
  PDFWRDEBUG {
    (setomap: #Xref = ) print XRef ld_length =only
    (, #RMap = ) print RMap ld_length =
  } if
} bind def

% ================ Writing ================ %

% ---------------- Low-level output ---------------- %

% Write a string on the output file.
/ows {			% <string> ows -
  OFile exch writestring
} bind def

% ---------------- Scalars ---------------- %

% Note that the '#' character isn't legal in a name unless it is a prefix
% for a hex encoded character (for PDF 1.2 and later). The following assumes
% that the names are already valid PDF 1.2+ names so that  we can treat the
% '#' as a legal character. The next two hex characters are already in the
% set of valid name characters. PDF 1.1 and earlier allowed spaces in names
% which probably wouldn't make it past the tokenizer anyway.
/pdfnamechars
  (!"$&'*+,-.0123456789:;=?@ABCDEFGHIJKLMNOPQRSTUVWXYZ\\^_`abcdefghijklmnopqrstuvwxyz|~)
readonly def
/pdfwritename {		% <name> pdfwritename -
  (/) ows .namestring {
    ( ) dup 0 4 -1 roll put
    //pdfnamechars 1 index search {
      pop pop pop
    } {
      pop 0 get 256 add 16 =string cvrs
      dup 0 (#) 0 get put
    } ifelse ows
  } forall
} bind def

% ---------------- Composite objects ---------------- %

/pdfwriteprocs mark
  /resolveR { pdfwriteref }
  /O { pdfwritenewref }
.dicttomark readonly def
/pdfwritearray {	% <array> pdfwritearray -
  dup xcheck {
    aload pop //pdfwriteprocs exch get exec
  } {
        % Because of a bug in Acrobat's parser for linearization parameters,
        % we have to include some whitespace after the opening [ (!).
    ([ ) ows { pdfwritevalue (\n) ows } forall (]) ows
  } ifelse
} bind def

/pdfwritedict {		% <dict> pdfwritedict -
  dup xcheck {
    pdfwritestream
  } {
    (<<) ows {
      exch pdfwritevalue ( ) ows pdfwritevalue (\n) ows
    } forall (>>) ows
  } ifelse
} bind def

% ---------------- References ---------------- %

/pdfwritenewref {	% <newobj#> pdfwritenewref -
  OFile exch write=only ( 0 R) ows
} bind def

/pdfwriteref {		% <obj#> <gen#> pdfwriteref -
  1 index omapnew {
    ToWrite dup length 5 -2 roll 2 packedarray put
  } {
    exch pop exch pop
  } ifelse
  pdfwritenewref
} bind def

/pdfcopystring 200 string def
/pdfwritestream {	% <streamdict> pdfwritestream -
        % Remove File, FilePosition, and StreamKey;
        % optimize by replacing an indirect Length.
  dup dup length dict copy
        % Stack: origdict dict
  dup /File undef dup /FilePosition undef dup /StreamKey undef
  dup /Length known {
    dup /Length get dup oforce ne {
      dup /Length 2 copy oget put
    } if
  } {
    1 index /File get dup
    3 index /FilePosition get setfileposition
    dup 0 (endstream) /SubFileDecode filter flushfile
    .fileposition 9 sub
    2 index /FilePosition get sub
    1 index exch /Length exch put
  } ifelse
  exch dup /File get dup 3 -1 roll /FilePosition get setfileposition
  pdfcopystream
} bind def

% We put copying the stream contents in separate procedures so that we
% can replace this function if desired.
/pdfcopybytes {		% <fromfile> <tofile> <length> pdfcopybytes -
  {
    dup 0 eq { exit } if
    //pdfcopystring 0 2 index 2 index length .min getinterval
    3 index exch readstring 3 1 roll
    3 index 1 index writestring length sub exch not { exit } if
  } loop pop pop pop
} bind def
/pdfcopystream {	% <newstreamdict> <file> pdfcopystream -
                        %   (file has been positioned)
  1 index pdfwritevalue (stream\n) ows
  exch /Length get OFile exch pdfcopybytes
  (endstream) ows
} bind def

% ---------------- General values/objects ---------------- %

/pdfwritetypes mark
        % Scalars
  /nulltype { pop (null) ows } bind
  /integertype { =string cvs ows } bind
  /booleantype 1 index
  /realtype {
    =string cvs
    (e) search {  % PDF has no exponential format
      exch pop % exp pre
      exch cvi exch
      (-) anchorsearch { ows } if
      (.) search {
        exch pop            % exp (frac) (int)
        1 index length      % exp (frac) (int) len
        3 1 roll            % exp len (frac) (int)
        exch concatstrings  % exp len (int_frac)
        3 1 roll sub        % (int_frac) exp-len
        exch                % exp-len (int_frac)
      } if                  % exp (mant)
      1 index 0 ge {
        ows { (0) ows } repeat (.) ows
      } {
        dup length          % exp (mant) len
        3 -1 roll add       % (mant) exp+len
        dup 0 le {
          (0.) ows neg { (0) ows } repeat ows
        } {
          2 copy 0 exch getinterval ows
          (.) ows
          1 index length 1 index sub getinterval ows
        } ifelse
      } ifelse
    } {
      ows
    } ifelse
  } bind
  /stringtype { OFile exch write===only } bind
  /nametype { pdfwritename } bind
        % Composite/reference objects
  /arraytype { pdfwritearray } bind
  /packedarraytype 1 index
  /dicttype { pdfwritedict } bind
.dicttomark readonly def

/pdfwritevalue {	% <obj> pdfwritevalue -
  PDFWRDEBUG { (****Writing: ) print dup === flush } if
  //pdfwritetypes 1 index type get exec
} bind def

% We make pdfwriteobjdef a separate procedure for external use.
/pdfwriteobjheader {	% <newobj#> pdfwriteobjheader -
  XRef 1 index OFile .fileposition ld_put
  PDFWRDEBUG { (XRef\() print dup =only (\) = ) print XRef 1 index ld_get = } if
  OFile exch write=only ( 0 obj\n) ows
} bind def
/pdfwriteobjdef {	% <newobj#> <value> pdfwriteobjdef -
  exch pdfwriteobjheader
  pdfwritevalue (\nendobj\n) ows
} bind def
/pdfwriteobj {		% <obj#> <gen#> pdfwriteobj -
  1 index exch resolveR exch omap exch pdfwriteobjdef
} bind def

% ---------------- File-level entities ---------------- %

% Write a PDF file header.
% Free variables: OFile, PDFversion.
/pdfwriteheader {	% - pdfwriteheader -
  (%PDF-) ows OFile PDFversion write=
  (%\347\363\317\323\n) ows
} bind def

% Write a cross-reference table and trailer.
/pdfwritexref {		% <firstobj#> <#objs> pdfwritexref -
  (xref\n) ows
  OFile 2 index write=only ( ) ows OFile 1 index write=
  1 index add 1 sub 1 exch {
    dup 0 eq {
      pop (0000000000 65535 f \n) ows
    } {
      XRef exch ld_get 1000000000 add =string cvs
      dup 0 (0) 0 get put
      ows ( 00000 n \n) ows
    } ifelse
  } for
} bind def
/pdfwritetrailer {	% <trailer> pdfwritetrailer -
  (trailer\n) ows
  % Since we always write a complete "classic" xref, the Trailer may need to be adjusted:
  % - remove keys that pertain to xref-streams and hybrid-xref PDFs;
  % - if it's a PDF stream, turn it into a PDF dict by removing keys used for
  %   PDF streams (both standard and GS-specific), and the executable attribute
  dup /XRefStm known 1 index xcheck or {
    dup length dict copy
    dup {/Type/Index/W /XRefStm /Filter/DecodeParms/Length/File/FilePosition} {
      undef dup
    } forall pop
    % note: the executable attribute is "removed" by not being copied
  } if
  pdfwritevalue
  (\n) ows
} bind def
/pdfwritestartxref {	% <startpos> pdfwritestartxref -
  (startxref\n) ows OFile exch write=
  (%%EOF\n) ows
} bind def

% ================ Top-level control ================ %

/pdfwrite {		% <file> <trailer> pdfwrite -
  10 dict begin
  /trailer exch def
  /OFile exch def
  /ToWrite 100 dict def
  omapinit

        % Write the PDF file header.

  pdfwriteheader

        % Write the objects.

  trailer {
    exch pop dup xcheck {	% The only executable objects are references.
      aload pop pop pdfwriteobj
    } {
      pop
    } ifelse
  } forall
        % Walk the object graph.
  {
    ToWrite dup length dup 0 eq { pop pop exit } if
    1 sub 2 copy get 3 1 roll undef aload pop pdfwriteobj
  } loop

        % Write the xref table and trailer.

  /xref OFile fileposition def
  0 XRef ld_length 1 add pdfwritexref
  trailer dup length 1 add dict copy trailer xcheck { cvx } if
  dup /Size XRef ld_length 1 add put pdfwritetrailer
  xref pdfwritestartxref

  end
} bind def

.setglobal .setlanguagelevel