harvey/sys/src/cmd/gs/lib/pdfwrite.ps

%    Copyright (C) 1999, 2000, 2001 Aladdin Enterprises.  All rights reserved.
% 
% This file is part of AFPL Ghostscript.
% 
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% distributor accepts any responsibility for the consequences of using it, or
% for whether it serves any particular purpose or works at all, unless he or
% she says so in writing.  Refer to the Aladdin Free Public License (the
% "License") for full details.
% 
% Every copy of AFPL Ghostscript must include a copy of the License, normally
% in a plain ASCII text file named PUBLIC.  The License grants you the right
% to copy, modify and redistribute AFPL Ghostscript, but only under certain
% conditions described in the License.  Among other things, the License
% requires that the copyright notice and this notice be preserved on all
% copies.

% $Id: pdfwrite.ps,v 1.7 2001/07/30 07:16:32 lpd Exp $
% 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#]

/.setlanguagelevel where { pop 2 .setlanguagelevel } if
.currentglobal true .setglobal

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

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

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

% Map an object number.
/omapnew {		% <oldobj#> omap <newobj#> <isnew>
  RMap 1 index .knownget {
    exch pop false
  } {
    PDEBUG { (omap\() print dup =only } if
    RMap dup length 1 add 2 index exch dup 5 1 roll put pop true
    PDEBUG { (\) = ) print 1 index = } if
  } ifelse
} 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 dup length dict copy XRef dup length dict copy]
  } {
    [RMap XRef] omapinit
  } ifelse
} bind def
/setomap {		% <omap> setomap -
  aload pop /XRef exch def /RMap exch def
  PDEBUG {
    (setomap: #Xref = ) print XRef length =only
    (, #RMap = ) print RMap length =
  } if
} bind def

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

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

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

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

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

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

/pdfwriteref {		% <obj#> <gen#> pdfwriteref -
  1 index omapnew {
    ToWrite dup length 5 -2 roll 2 packedarray put
  } {
    exch pop exch pop
  } ifelse
  pdfwritenewref
} 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 get dup oforce ne {
    dup /Length 2 copy oget put
  } if
  exch dup /File get dup 3 -1 roll /FilePosition get setfileposition
  pdfcopystream
} 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
} def
/pdfcopystream {	% <newstreamdict> <file> pdfcopystream -
			%   (file has been positioned)
  1 index pdfwritevalue (stream\n) ows
  exch /Length get OFile exch pdfcopybytes
  (endstream) ows
} def

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

/pdfwritetypes mark
	% Scalars
  /nulltype { pop (null) ows }
  /integertype { =string cvs ows }
  /booleantype 1 index
  /realtype { OFile exch write===only }
  /stringtype 1 index
  /nametype { pdfwritename }
	% Composite/reference objects
  /arraytype { pdfwritearray }
  /packedarraytype 1 index
  /dicttype { pdfwritedict }
.dicttomark readonly def

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

% We make pdfwriteobjdef a separate procedure for external use.
/pdfwriteobjheader {	% <newobj#> pdfwriteobjheader -
  XRef 1 index OFile .fileposition put
  PDEBUG { (XRef\() print dup =only (\) = ) print XRef 1 index get = } if
  OFile exch write=only ( 0 obj\n) ows
} def
/pdfwriteobjdef {	% <newobj#> <value> pdfwriteobjdef -
  exch pdfwriteobjheader
  pdfwritevalue (\nendobj\n) ows
} def
/pdfwriteobj {		% <obj#> <gen#> pdfwriteobj -
  1 index exch resolveR exch omap exch pdfwriteobjdef
} 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 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 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 length 1 add pdfwritexref
  trailer dup length 1 add dict copy
  dup /Size XRef length 1 add put pdfwritetrailer
  xref pdfwritestartxref

  end
} def

.setglobal