922 lines
34 KiB
PostScript
922 lines
34 KiB
PostScript
% Copyright (C) 1994-2003 artofcode LLC. All rights reserved.
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%
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% This software is provided AS-IS with no warranty, either express or
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% implied.
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%
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% This software is distributed under license and may not be copied,
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% modified or distributed except as expressly authorized under the terms
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% of the license contained in the file LICENSE in this distribution.
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%
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% For more information about licensing, please refer to
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% http://www.ghostscript.com/licensing/. For information on
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% commercial licensing, go to http://www.artifex.com/licensing/ or
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% contact Artifex Software, Inc., 101 Lucas Valley Road #110,
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% San Rafael, CA 94903, U.S.A., +1(415)492-9861.
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% $Id: pdf_base.ps,v 1.48 2005/09/16 19:01:30 ray Exp $
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% pdf_base.ps
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% Basic parser for PDF reader.
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% This handles basic parsing of the file (including the trailer
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% and cross-reference table), as well as objects, object references,
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% streams, and name/number trees; it doesn't include any facilities for
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% making marks on the page.
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/.setlanguagelevel where { pop 2 .setlanguagelevel } if
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.currentglobal true .setglobal
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/pdfdict where { pop } { /pdfdict 100 dict def } ifelse
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pdfdict begin
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% Define the name interpretation dictionary for reading values.
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/valueopdict mark
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(<<) cvn { mark } bind % don't push an actual mark!
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(>>) cvn { { .dicttomark } stopped {
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( **** File has an unbalanced >> \(close dictionary\).\n)
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pdfformaterror
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} if
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} bind
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([) cvn { mark } bind % ditto
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(]) cvn dup load
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% /true true % see .pdfexectoken below
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% /false false % ibid.
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% /null null % ibid.
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/F dup cvx % see Objects section below
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/R dup cvx % see Objects section below
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/stream dup cvx % see Streams section below
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.dicttomark readonly def
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% ------ Utilities ------ %
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% Define a scratch string. The PDF language definition says that
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% no line in a PDF file can exceed 255 characters.
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/pdfstring 255 string def
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% Read the previous line of a file. If we aren't at a line boundary,
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% read the line containing the current position.
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% Skip any blank lines.
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/prevline % - prevline <startpos> <substring>
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{ PDFfile fileposition dup () pdfstring
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2 index 257 sub 0 .max PDFfile exch setfileposition
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{ % Stack: initpos linepos line string
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PDFfile fileposition
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PDFfile 2 index readline pop
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dup length 0 gt
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{ 3 2 roll 5 -2 roll pop pop 2 index }
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{ pop }
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ifelse
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% Stack: initpos linepos line string startpos
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PDFfile fileposition 5 index ge { exit } if
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pop
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}
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loop pop pop 3 -1 roll pop
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} bind def
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% Handle the PDF 1.2 #nn escape convention when reading from a file.
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% This should eventually be done in C.
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/.pdffixname { % <execname> .pdffixname <execname'>
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PDFversion 1.2 ge {
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dup .namestring (#) search {
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name#escape cvn exch pop
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} {
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pop
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} ifelse
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} if
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} bind def
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/name#escape % <post> <(#)> <pre> name#escape <string>
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{ exch pop
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1 index 2 () /SubFileDecode filter dup (x) readhexstring
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% Stack: post pre stream char t/f
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not { % tolerate, but complain about bad syntax
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pop closefile (#) concatstrings exch
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( **** Warning: Invalid hex following '#' name escape, using literal '#' in name.\n)
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pdfformaterror
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} {
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exch closefile concatstrings
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exch 2 1 index length 2 sub getinterval
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} ifelse
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(#) search { name#escape } if concatstrings
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} bind def
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% Execute a file, interpreting its executable names in a given
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% dictionary. The name procedures may do whatever they want
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% to the operand stack.
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/.pdftokenerror { % <count> <opdict> <errtoken> .pdftokenerror -
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BXlevel 0 le {
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( **** Unknown operator: ') pdfformaterror
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dup =string cvs pdfformaterror
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% Attempt a retry scan of the element after changing to PDFScanInvNum
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<< /PDFScanInvNum true >> setuserparams
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=string cvs
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token pop exch pop dup type
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dup /integertype eq exch /realtype eq or {
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exch pop exch pop
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(', processed as number, value: ) pdfformaterror
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dup =string cvs pdfformaterror (\n) pdfformaterror
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<< /PDFScanInvNum null >> setuserparams % reset to default scanning rules
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false % suppress any stack cleanup
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} {
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% error was non-recoverable with modified scanning rules
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('\n) pdfformaterror
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true
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} ifelse
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} {
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true
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} ifelse
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{ % clean up the operand stack if this was non-recoverable
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pop pop count exch sub { pop } repeat % pop all the operands
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} if
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} bind def
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/.pdfexectoken { % <count> <opdict> <exectoken> .pdfexectoken ?
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PDFDEBUG {
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pdfdict /PDFSTEPcount known not { pdfdict /PDFSTEPcount 1 .forceput } if
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PDFSTEP {
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pdfdict /PDFtokencount 2 copy .knownget { 1 add } { 1 } ifelse .forceput
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PDFSTEPcount 1 gt {
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pdfdict /PDFSTEPcount PDFSTEPcount 1 sub .forceput
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} {
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dup ==only
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( step # ) print PDFtokencount =only
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( ? ) print flush 1 false .outputpage
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(%stdin) (r) file 255 string readline {
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token {
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exch pop pdfdict /PDFSTEPcount 3 -1 roll .forceput
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} {
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pdfdict /PDFSTEPcount 1 .forceput
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} ifelse % token
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} {
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pop /PDFSTEP false def % EOF on stdin
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} ifelse % readline
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} ifelse % PDFSTEPcount > 1
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} {
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dup ==only () = flush
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} ifelse % PDFSTEP
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} if % PDFDEBUG
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2 copy .knownget {
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exch pop exch pop exch pop exec
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} {
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% Normally, true, false, and null would appear in opdict
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% and be treated as "operators". However, there is a
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% special fast case in the PostScript interpreter for names
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% that are defined in, and only in, systemdict and/or
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% userdict: putting these three names in the PDF dictionaries
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% destroys this property for them, slowing down their
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% interpretation in all PostScript code. Therefore, we
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% check for them explicitly here instead.
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dup dup dup /true eq exch /false eq or exch /null eq or {
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exch pop exch pop //systemdict exch get
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} {
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.pdftokenerror
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} ifelse
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} ifelse
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} bind def
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/.pdfrun { % <file> <opdict> .pdfrun -
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% Construct a procedure with the stack depth, file and opdict
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% bound into it.
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1 index cvlit count 2 sub 3 1 roll mark mark 5 2 roll
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{ % Stack: ..operands.. count opdict file
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token {
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dup type /nametype eq {
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dup xcheck {
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.pdfexectoken
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} {
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.pdffixname
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exch pop exch pop PDFDEBUG {
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PDFSTEPcount 1 le {
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dup ==only ( ) print flush
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} if
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} if
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} ifelse
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} {
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exch pop exch pop PDFDEBUG {
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PDFSTEPcount 1 le {
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dup ==only ( ) print flush
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} if
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} if
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} ifelse
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} {
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(%%EOF) cvn cvx .pdfexectoken
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} ifelse
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}
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aload pop .packtomark cvx
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/loop cvx 2 packedarray cvx
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{ stopped /PDFsource } aload pop
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PDFsource
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{ store { stop } if } aload pop .packtomark cvx
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/PDFsource 3 -1 roll store exec
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} bind def
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% Execute a file, like .pdfrun, for a marking context.
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% This temporarily rebinds LocalResources and DefaultQstate.
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/.pdfruncontext { % <resdict> <file> <opdict> .pdfruncontext -
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/.pdfrun load LocalResources DefaultQstate
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/LocalResources 7 -1 roll store
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/DefaultQstate qstate store
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3 .execn
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/DefaultQstate exch store
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/LocalResources exch store
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} bind def
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% Get the depth of the PDF operand stack. The caller sets pdfemptycount
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% before calling .pdfrun or .pdfruncontext. It is initially set by
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% pdf_main, and is also set by any routine which changes the operand
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% stack depth (currently .pdfpaintproc, although there are other callers
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% of .pdfrun{context} which have not been checked for opstack depth.
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/.pdfcount { % - .pdfcount <count>
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count pdfemptycount sub
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} bind def
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% ================================ Objects ================================ %
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% Since we may have more than 64K objects, we have to use a 2-D array to
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% hold them (and the parallel Generations structure).
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/lshift 9 def
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/lnshift lshift neg def
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/lsubmask 1 lshift bitshift 1 sub def
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/lsublen lsubmask 1 add def
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/larray { % - larray <larray>
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[ [] ]
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} bind def
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/lstring { % - lstring <lstring>
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[ () ]
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} bind def
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/ltype { % <lseq> type <type>
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0 get type
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} bind def
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/lget { % <lseq> <index> lget <value>
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dup //lsubmask and 3 1 roll //lnshift bitshift get exch get
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} bind def
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/lput { % <lseq> <index> <value> lput -
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3 1 roll
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dup //lsubmask and 4 1 roll //lnshift bitshift get
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3 1 roll put
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} bind def
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/llength { % <lseq> llength <length>
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dup length 1 sub dup //lshift bitshift
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3 1 roll get length add
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} bind def
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% lgrowto assumes newlength > llength(lseq)
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/growto { % <string/array> <length> growto <string'/array'>
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1 index type /stringtype eq { string } { array } ifelse
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2 copy copy pop exch pop
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} bind def
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/lgrowto { % <lseq> <newlength> lgrowto <lseq'>
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dup //lsubmask add //lnshift bitshift dup 3 index length gt {
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% Add more sub-arrays. Start by completing the last existing one.
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% Stack: lseq newlen newtoplen
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3 -1 roll dup llength 1 sub //lsubmask or 1 add lgrowto
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% Stack: newlen newtoplen lseq
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[ exch aload pop
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counttomark 2 add -1 roll % newtoplen
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counttomark sub { dup 0 0 getinterval lsublen growto } repeat
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dup 0 0 getinterval ] exch
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} {
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pop
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} ifelse
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% Expand the last sub-array.
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1 sub //lsubmask and 1 add
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exch dup dup length 1 sub 2 copy
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% Stack: newsublen lseq lseq len-1 lseq len-1
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get 5 -1 roll growto put
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} bind def
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/lforall { % <lseq> <proc> lforall -
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/forall cvx 2 packedarray cvx forall
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} bind def
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% We keep track of PDF objects using the following PostScript variables:
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%
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% Generations (lstring): Generations[N] holds 1+ the current
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% generation number for object number N. (As far as we can tell,
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% this is needed only for error checking.) For free objects,
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% Generations[N] is 0.
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%
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% Objects (larray): If object N is loaded, Objects[N] is the actual
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% object; otherwise, Objects[N] is an executable integer giving
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% the file offset of the object's location in the file. If
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% ObjectStream[N] is non-zero then Objects[N] contains the index
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% into the object stream instead of the file offset of the object.
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%
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% ObjectStream (larray): If object N is in an object stream then
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% ObjectStream[N] holds the object number of the object stream.
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% Otherwise ObjectStream[N] contains 0. If ObjectStream[N]
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% is non-zero then Objects[N] contains the index into the object
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% stream.
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%
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% GlobalObjects (dictionary): If object N has been resolved in
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% global VM, GlobalObjects[N] is the same as Objects[N]
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% (except that GlobalObjects itself is stored in global VM,
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% so the entry will not be deleted at the end of the page).
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%
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% IsGlobal (lstring): IsGlobal[N] = 1 iff object N was resolved in
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% global VM. This is an accelerator to avoid having to do a
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% dictionary lookup in GlobalObjects when resolving every object.
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% Initialize the PDF object tables.
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/initPDFobjects { % - initPDFobjects -
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/ObjectStream larray def
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/Objects larray def
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/Generations lstring def
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.currentglobal true .setglobal
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/GlobalObjects 20 dict def
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.setglobal
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/IsGlobal lstring def
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} bind def
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% Grow the tables to a specified size.
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/growPDFobjects { % <minsize> growPDFobjects -
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dup ObjectStream llength gt {
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dup ObjectStream exch lgrowto /ObjectStream exch def
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} if
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dup Objects llength gt {
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dup Objects exch lgrowto /Objects exch def
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} if
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dup Generations llength gt {
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dup Generations exch lgrowto /Generations exch def
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} if
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dup IsGlobal llength gt {
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dup IsGlobal exch lgrowto /IsGlobal exch def
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} if
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pop
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} bind def
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% We represent an unresolved object reference by a procedure of the form
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% {obj# gen# resolveR}. This is not a possible PDF object, because PDF has
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% no way to represent procedures. Since PDF in fact has no way to represent
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% any PostScript object that doesn't evaluate to itself, we can 'force'
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% a possibly indirect object painlessly with 'exec'.
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% Note that since we represent streams by executable dictionaries
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% (see below), we need both an xcheck and a type check to determine
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% whether an object has been resolved.
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/resolved? { % <object#> resolved? <value> true
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% <object#> resolved? false
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Objects 1 index lget dup xcheck { % Check if executable
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dup type /integertype eq { % Check if an integer
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% Check whether the object is in GlobalObjects.
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pop IsGlobal 1 index lget 0 eq { % 0 --> Not in GlabalObjects
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pop false % The object is not resolved
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} { % The object is in GlobalObjects
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% Update Objects from GlobalObjects
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PDFDEBUG { (%Global=>local: ) print dup == } if
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GlobalObjects 1 index get dup Objects 4 1 roll lput true
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} ifelse
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} { % Else object is executable but not integer
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exch pop true % Therefore must be executable dict. (stream)
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} ifelse
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} { % Else object is not executable.
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exch pop true % Therefore it must have been resolved.
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} ifelse
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} bind def
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/oforce /exec load def
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/oget { % <array> <index> oget <object>
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% <dict> <key> oget <object>
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% Before release 6.20, this procedure stored the resolved
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% object back into the referring slot. In order to support
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% PDF linearization, we no longer do this.
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get oforce
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} bind def
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/oforce_array { % <array> oforce_array <array>
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[ exch { oforce } forall ]
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} bind def
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/oforce_elems { % <array> oforce_elems <first> ... <last>
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{ oforce } forall
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} bind def
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% A null value in a dictionary is equivalent to an omitted key;
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% we must check for this specially.
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/knownoget { % <dict> <key> knownoget <value> true
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% <dict> <key> knownoget false
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% See oget above regarding this procedure.
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.knownget {
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oforce dup null eq { pop false } { true } ifelse
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} {
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false
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} ifelse
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} bind def
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% PDF 1.1 defines a 'foreign file reference', but not its meaning.
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% Per the specification, we convert these to nulls.
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/F { % <file#> <object#> <generation#> F <object>
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% Some PDF 1.1 files use F as a synonym for f!
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.pdfcount 3 lt { f } { pop pop pop null } ifelse
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} bind def
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% Verify the generation number for a specified object
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% Note: The values in Generations is the generation number plus 1.
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% If the value in Generations is zero then the object is free.
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/checkgeneration { % <object#> <generation#> checkgeneration <object#> <OK>
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Generations 2 index lget 1 sub 1 index eq { % If generation # match ...
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pop true % Then return true
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} { % Else not a match ...
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QUIET not { % Create warning message if not QUIET
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Generations 2 index lget 0 eq { % Check if object is free ...
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( **** Warning: reference to free object: )
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} {
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( **** Warning: wrong generation: )
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} ifelse
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2 index =string cvs concatstrings ( ) concatstrings % put obj #
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exch =string cvs concatstrings ( R\n) concatstrings % put gen #
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pdfformaterror % Output warning message
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} { % Else QUIET ...
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pop % Pop generation umber
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} ifelse false % Return false if gen # not match
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} ifelse
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} bind def
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/R { % <object#> <generation#> R <object>
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/resolveR cvx 3 packedarray cvx
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} bind def
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% If we encounter an object definition while reading sequentially,
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% we just store it away and keep going.
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/objopdict mark
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valueopdict { } forall
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/endobj dup cvx
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.dicttomark readonly def
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/obj { % <object#> <generation#> obj <object>
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PDFfile objopdict .pdfrun
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} bind def
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/endobj { % <object#> <generation#> <object> endobj <object>
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3 1 roll
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% Read the xref entry if we haven't yet done so.
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% This is only needed for generation # checking.
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1 index resolved? {
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pop
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} if
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checkgeneration {
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% The only global objects we bother to save are
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% (resource) dictionaries.
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1 index dup gcheck exch type /dicttype eq and {
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PDFDEBUG { (%Local=>global: ) print dup == } if
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GlobalObjects 1 index 3 index put
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IsGlobal 1 index 1 put
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} if
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Objects exch 2 index lput
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} {
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pop pop null
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} ifelse
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} bind def
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% When resolving an object reference in an object stream, we stop at
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% the end of file. Note: Objects in an object stream do not have either
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% a starting 'obj' or and ending 'endobj'.
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/resolveobjstreamopdict mark
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valueopdict { } forall
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(%%EOF) cvn { exit } bind
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.dicttomark readonly def
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% Note: This version of this function is not currently being used.
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% Resolve all objects in an object stream
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/resolveobjectstream { % <object stream #> resolveobjectstream -
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PDFDEBUG { (%Resolving object stream: ) print } if
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0 resolveR % Get the objectstream dict, all objstrms use 0 as the gen #
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dup /First get % Save location of first object onto the stack
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1 index /N get % Save number of objects onto the stack
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2 index false resolvestream % Convert stream dict into a stream
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/ReusableStreamDecode filter % We need to be able to position stream
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% Objectstreams begin with list of object numbers and locations
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% Create two arrays to hold object numbers and stream location
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1 index array % Array for holding object number
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2 index array % Array for holding stream object location
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% Get the object numbers and locations.
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0 1 5 index 1 sub { % Loop and collect obj # and locations
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% Stack: objstreamdict First N objectstream [obj#] [loc] index
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2 index 1 index % Setup to put obj# into object number array
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5 index token pop put % Get stream, then get obj# and put into array
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1 index 1 index % Setup to put object loc into location array
|
|
5 index token pop put % Get stream, get obj loc and put into array
|
|
pop % Remove loop index
|
|
} for
|
|
% Create a bytestring big enough for reading any object data
|
|
% Scan for the size of the largest object
|
|
0 0 % Init max object size and previous location
|
|
2 index { % Loop through all object locations
|
|
% Stack: ... maxsize prevloc currentloc
|
|
dup 4 1 roll % Save copy of object location into stack
|
|
exch sub % Object size = currentloc - prevloc
|
|
.max % Determine maximum object size
|
|
exch % Put max size under previous location
|
|
} forall
|
|
pop % Remove previous location
|
|
.bigstring % Create bytestring based upon max obj size
|
|
% Move to the start of the object data
|
|
3 index 6 index % Get objectstream and start of first object
|
|
setfileposition % Move to the start of the data
|
|
% Read the data for all objects except the last. We do
|
|
% not know the size of the last object so we need to treat
|
|
% it as a special case.
|
|
0 1 6 index 2 sub {
|
|
dup 4 index exch get % Get our current object number
|
|
% Stack: objstreamdict First N objectstream [obj#] [loc]
|
|
% bytestring loopindex object#
|
|
dup resolved? { % If we already have this object
|
|
(yyy) = pstack (yyy) = flush xxx
|
|
pop pop % Remove object and object number
|
|
1 add 2 index exch get % Get location of next object
|
|
6 index add 6 index exch % Form location of next object and get stream
|
|
setfileposition % Move to the start of the next object data
|
|
} { % Else this is a new object ...
|
|
% We are going to create a string for reading the object
|
|
2 index 0 % use our working string
|
|
% Determine the size of the object
|
|
5 index 4 index 1 add get % Get location of the next object
|
|
6 index 5 index get % Get location of this object
|
|
sub % Size of object = next loc - this loc
|
|
getinterval % Create string for reading object
|
|
6 index exch readstring pop % Read object
|
|
/ReusableStreamDecode filter % Convert string into a stream
|
|
resolveobjstreamopdict .pdfrun % Get PDF object
|
|
Objects exch 2 index exch lput % Put object into Objects array
|
|
pop pop % Remove object # and loop index
|
|
} ifelse
|
|
} for
|
|
pop pop % Remove our working string and loc array
|
|
% Now read the last object in the object stream. Since it
|
|
% is the last object, we can use the original stream and
|
|
% terminate when we hit the end of the stream
|
|
% Stack: objstreamdict First N objectstream [obj#]
|
|
2 index 1 sub get % Get our current object number
|
|
dup resolved? not { % If we do not already have this object
|
|
exch % Get our object stream
|
|
resolveobjstreamopdict .pdfrun % Get PDF object
|
|
Objects exch 2 index exch lput % Put object into Objects array
|
|
} if
|
|
pop pop pop pop % Clear stack
|
|
} bind def
|
|
|
|
% Resolve all objects in an object stream
|
|
/resolveobjectstream { % <object stream #> resolveobjectstream -
|
|
PDFDEBUG { (%Resolving object stream: ) print } if
|
|
0 resolveR % Get the objectstream dict, all objstrms use 0 as the gen #
|
|
dup /Type get /ObjStm ne { % Verify type is object stream
|
|
( **** Incorrect Type in object stream dictionary.\n) pdfformaterror
|
|
/resolveobjectstream cvx /typecheck signalerror
|
|
} if
|
|
dup /N get % Save number of objects onto the stack
|
|
1 index false resolvestream % Convert stream dict into a stream
|
|
/ReusableStreamDecode filter % We need to be able to position stream
|
|
% Objectstreams begin with list of object numbers and locations
|
|
1 index array % Create array for holding object number
|
|
% Get the object numbers
|
|
0 1 4 index 1 sub { % Loop and collect obj numbers
|
|
% Stack: objstreamdict N PDFDEBUG objectstream [obj#] loopindex
|
|
1 index 1 index % Setup to put obj# into object number array
|
|
4 index token pop put % Get stream, then get obj# and put into array
|
|
2 index token pop pop pop % Get stream, get obj loc and clear stack
|
|
} for
|
|
% Move to the start of the object data
|
|
1 index 4 index /First get % Get objectstream and start of first object
|
|
setfileposition % Move to the start of the data
|
|
% We disable PDFDEBUG while reading the data stream. We will
|
|
% print the data later
|
|
PDFDEBUG /PDFDEBUG false def % Save PDFDEBUG and disable it while reading
|
|
% Read the data for all objects. We check to see if we get
|
|
% the number of objects that we expect.
|
|
% Stack: objstreamdict N objectstream [obj#] PDFDEBUG
|
|
mark 4 -1 roll % Get objectstream
|
|
count 5 index add % Determine stack depth with objects
|
|
/PDFObjectStkCount exch def
|
|
resolveobjstreamopdict .pdfrun % Get PDF objects
|
|
PDFObjectStkCount count ne { % Check stack depth
|
|
( **** Incorrect object count in object stream.\n) pdfformaterror
|
|
/resolveobjectstream cvx /rangecheck signalerror
|
|
} if
|
|
% We have the object data
|
|
counttomark array astore % Put objects into an array
|
|
exch pop % Remove mark
|
|
exch /PDFDEBUG exch def % Restore PDFDEBUG flag
|
|
% Save the objects into Objects
|
|
0 1 2 index length 1 sub { % Loop through all objects
|
|
% Stack: objstreamdict N [obj#] [objects] loopindex
|
|
dup 3 index exch get % Get our current object number
|
|
dup resolved? { % If we already have this object
|
|
pop pop % Remove object and object number
|
|
} { % Else if we do not have this object
|
|
PDFDEBUG { (%Resolving compressed object: [) print dup =only ( 0]) = } if
|
|
Objects exch 3 index % Put the object into Objects
|
|
3 index get
|
|
PDFDEBUG { dup === flush } if
|
|
lput
|
|
} ifelse
|
|
pop % Remove loop index
|
|
} for
|
|
pop pop pop pop % Remove objstream, N, (obj#], and [objects]
|
|
} bind def
|
|
|
|
% When resolving an object reference, we stop at the endobj or endstream.
|
|
/resolveopdict mark
|
|
valueopdict { } forall
|
|
/endstream { endobj exit } bind
|
|
/endobj { endobj exit } bind
|
|
% OmniForm generates PDF file with endobj missing in some
|
|
% objects. AR ignores this. So we have to do it too.
|
|
/obj { pop pop endobj exit } bind
|
|
.dicttomark readonly def
|
|
|
|
/resolveR { % <object#> <generation#> resolveR <object>
|
|
PDFDEBUG {
|
|
PDFSTEPcount 1 le {
|
|
(%Resolving: ) print 2 copy 2 array astore ==
|
|
} if
|
|
} if
|
|
1 index resolved? { % If object has already been resolved ...
|
|
exch pop exch pop % then clear stack and return object
|
|
} { % Else if not resolved ...
|
|
PDFfile fileposition 3 1 roll % Save current file position
|
|
1 index Objects exch lget % Get location of object from xref
|
|
3 1 roll checkgeneration { % Verify the generation number
|
|
% Stack: savepos objpos obj#
|
|
ObjectStream 1 index lget dup 0 eq { % Check if obj in not an objstream
|
|
pop exch PDFoffset add PDFfile exch setfileposition
|
|
PDFfile token pop 2 copy ne
|
|
{ ( **** Unrecoverable error in xref!\n) pdfformaterror
|
|
/resolveR cvx /rangecheck signalerror
|
|
}
|
|
if pop PDFfile token pop
|
|
PDFfile token pop /obj ne
|
|
{ ( **** Unrecoverable error in xref!\n) pdfformaterror
|
|
/resolveR cvx /rangecheck signalerror
|
|
}
|
|
if
|
|
pdf_run_resolve % PDFfile resolveopdict .pdfrun
|
|
} { % Else the object is in an ObjectStream
|
|
% Process an objectstream object. We are going to resolve all
|
|
% of the objects in sthe stream and place them into the Objects
|
|
% array.
|
|
% Stack: savepos objpos obj# objectstream#
|
|
resolveobjectstream
|
|
resolved? { % If object has already been resolved ...
|
|
exch pop % Remove object pos from stack.
|
|
} {
|
|
pop pop null % Pop objpos and obj#, put null for object
|
|
} ifelse
|
|
} ifelse
|
|
} { % Else the generation number is wrong
|
|
% Don't cache if the generation # is wrong.
|
|
pop pop null % Pop objpos and obj#, put null for object
|
|
} ifelse % ifelse generation number is correct
|
|
exch PDFfile exch setfileposition % Return to original file position
|
|
} ifelse
|
|
} bind def
|
|
|
|
% ================================ Streams ================================ %
|
|
|
|
% We represent a stream by an executable dictionary that contains,
|
|
% in addition to the contents of the original stream dictionary:
|
|
% /File - the file or string where the stream contents are stored,
|
|
% if the stream is not an external one.
|
|
% /FilePosition - iff File is a file, the position in the file
|
|
% where the contents start.
|
|
% /StreamKey - the key used to decrypt this stream, if any.
|
|
% We do the real work of constructing the data stream only when the
|
|
% contents are needed.
|
|
|
|
% Construct a stream. The length is not reliable in the face of
|
|
% different end-of-line conventions, but it's all we've got.
|
|
%
|
|
% PDF files are inconsistent about what may fall between the 'stream' keyword
|
|
% and the actual stream data, and it appears that no one algorithm can
|
|
% detect this reliably. We used to try to guess whether the file included
|
|
% extraneous \r and/or \n characters, but we no longer attempt to do so,
|
|
% especially since the PDF 1.2 specification states flatly that the only
|
|
% legal terminators following the 'stream' keyword are \n or \r\n, both of
|
|
% which are properly skipped and discarded by the token operator.
|
|
% Unfortunately, this doesn't account for other whitespace characters that
|
|
% may have preceded the EOL, such as spaces or tabs. Thus we back up one
|
|
% character and scan until we find the \n terminator.
|
|
/stream { % <dict> stream <modified_dict>
|
|
dup /Length oget 0 eq {
|
|
dup /Filter undef % don't confuse any filters that require data
|
|
} if
|
|
dup /F known dup PDFsource PDFfile eq or {
|
|
not {
|
|
dup /File PDFfile put
|
|
% make sure that we are just past the EOL \n character
|
|
PDFfile dup fileposition 1 sub setfileposition % back up one
|
|
{ PDFfile read pop dup 13 eq {
|
|
% If there had been a \n, token would have advanced over it
|
|
% thus, if the terminator was \r, we have a format error!
|
|
( **** Warning: stream operator not terminated by valid EOL.\n) pdfformaterror
|
|
pop exit % fileposition is OK (just past the \r).
|
|
} if
|
|
10 eq { exit } if
|
|
} loop % scan past \n
|
|
dup /FilePosition PDFfile fileposition put
|
|
PDFDEBUG {
|
|
PDFSTEPcount 1 le {
|
|
(%FilePosition: ) print dup /FilePosition get ==
|
|
} if
|
|
} if
|
|
} if
|
|
% Some (bad) PDf files have invalid stream lengths. This causes problems
|
|
% if we reposition beyond the end of the file. So we compare the given
|
|
% length to number of bytes left in the file.
|
|
dup /Length oget
|
|
dup PDFfile bytesavailable lt { % compare to to bytes left in file
|
|
PDFfile fileposition % reposition to the end of stream
|
|
add PDFfile exch setfileposition
|
|
} {
|
|
pop % bad stream length - do not reposition.
|
|
% This will force a length warning below
|
|
} ifelse
|
|
} {
|
|
pop
|
|
% We're already reading from a stream, which we can't reposition.
|
|
% Capture the sub-stream contents in a string.
|
|
dup /Length oget string PDFsource exch readstring
|
|
not {
|
|
( **** Warning: Unexpected EOF in stream!\n) pdfformaterror
|
|
/stream cvx /rangecheck signalerror
|
|
} if
|
|
1 index exch /File exch put
|
|
} ifelse
|
|
PDFsource {token} stopped {
|
|
pop null
|
|
} {
|
|
not { null } if
|
|
} ifelse
|
|
dup /endobj eq {
|
|
% Another case that Acrobat Reader handles -- 'endobj' without 'endstream'.
|
|
( **** Warning: stream missing 'endstream'.\n) pdfformaterror
|
|
pop /endstream % fake a valid endstream
|
|
} if
|
|
/endstream ne {
|
|
( **** Warning: stream Length incorrect.\n) pdfformaterror
|
|
dup /Length undef % prevent the use of the incorrect length.
|
|
cvx endobj exit % exit from .pdfrun now.
|
|
} if
|
|
cvx
|
|
} bind def
|
|
/endstream {
|
|
exit
|
|
} bind def
|
|
|
|
% Contrary to the published PDF (1.3) specification, Acrobat Reader
|
|
% accepts abbreviated filter names everywhere, not just for in-line images,
|
|
% and some applications (notably htmldoc) rely on this.
|
|
/unabbrevfilterdict mark
|
|
/AHx /ASCIIHexDecode /A85 /ASCII85Decode /CCF /CCITTFaxDecode
|
|
/DCT /DCTDecode /Fl /FlateDecode /LZW /LZWDecode /RL /RunLengthDecode
|
|
.dicttomark readonly def
|
|
|
|
% Extract and apply filters.
|
|
/filterparms { % <dict> <DPkey> <Fkey> filterparms
|
|
% <dict> <parms> <filternames>
|
|
2 index exch knownoget {
|
|
exch 2 index exch knownoget {
|
|
% Both filters and parameters.
|
|
exch dup type /nametype eq {
|
|
1 array astore exch
|
|
dup type /arraytype ne { 1 array astore } if exch
|
|
} if
|
|
} {
|
|
% Filters, but no parameters.
|
|
null exch
|
|
dup type /nametype eq { 1 array astore } if
|
|
} ifelse
|
|
} {
|
|
% No filters: ignore parameters, if any.
|
|
pop null { }
|
|
} ifelse
|
|
} bind def
|
|
/filtername { % <filtername> filtername <filtername'>
|
|
//unabbrevfilterdict 1 index .knownget { exch pop } if
|
|
dup /Filter resourcestatus { pop pop } {
|
|
Repaired exch % this error is not the creator's fault
|
|
( **** ERROR: Unable to process ) pdfformaterror
|
|
64 string cvs pdfformaterror
|
|
( data. Page will be missing data.\n) pdfformaterror
|
|
/Repaired exch store % restore the previous "Repaired" state
|
|
% provide a filter that returns EOF (no data)
|
|
/.EOFDecode
|
|
} ifelse
|
|
} bind def
|
|
/applyfilters { % <parms> <source> <filternames> applyfilters <stream>
|
|
2 index null eq {
|
|
{ filtername filter }
|
|
} {
|
|
{ % Stack: parms source filtername
|
|
2 index 0 oget dup null eq { pop } {
|
|
exch filtername dup /JBIG2Decode eq { exch jbig2cachectx exch } if
|
|
} ifelse filter
|
|
exch dup length 1 sub 1 exch getinterval exch
|
|
}
|
|
} ifelse forall exch pop
|
|
} bind def
|
|
|
|
% JBIG2 streams have an optional 'globals' stream obj for
|
|
% sharing redundant data between page images. Here we resolve
|
|
% that stream reference (if any) and run it through the decoder,
|
|
% creating a special -jbig2globalctx- postscript object our
|
|
% JBIG2Decode filter implementation looks for in the parm dict.
|
|
/jbig2cachectx { % <parmdict> jbig2cachectx <parmdict>
|
|
dup /JBIG2Globals knownoget {
|
|
dup /Length oget
|
|
% make global ctx
|
|
PDFfile fileposition 3 1 roll % resolvestream is not reentrant
|
|
exch true resolvestream exch .bytestring
|
|
.readbytestring pop .jbig2makeglobalctx
|
|
PDFfile 3 -1 roll setfileposition
|
|
1 index exch
|
|
/.jbig2globalctx exch put
|
|
} if
|
|
} bind def
|
|
|
|
% Resolve a stream dictionary to a PostScript stream.
|
|
% Streams with no filters require special handling:
|
|
% - Whether we are going to interpret the stream, or If we are just
|
|
% going to read data from them, we impose a SubFileDecode filter
|
|
% that reads just the requisite amount of data.
|
|
% Note that, in general, resolving a stream repositions PDFfile.
|
|
% Clients must save and restore the position of PDFfile themselves.
|
|
/resolvestream { % <streamdict> <readdata?> resolvestream <stream>
|
|
1 index /F knownoget {
|
|
% This stream is stored on an external file.
|
|
(r) file 3 -1 roll
|
|
/FDecodeParms /FFilter filterparms
|
|
% Stack: readdata? file dict parms filternames
|
|
4 -1 roll exch
|
|
pdf_decrypt_stream
|
|
applyfilters
|
|
} {
|
|
exch dup /FilePosition .knownget {
|
|
1 index /File get exch setfileposition
|
|
} if
|
|
% Stack: readdata? dict
|
|
/DecodeParms /Filter filterparms
|
|
% Stack: readdata? dict parms filternames
|
|
2 index /File get exch
|
|
% Stack: readdata? dict parms file/string filternames
|
|
pdf_decrypt_stream % add decryption if needed
|
|
dup length 0 eq {
|
|
% All the PDF filters have EOD markers, but in this case
|
|
% there is no specified filter.
|
|
pop exch pop
|
|
% Stack: readdata? dict file/string
|
|
2 index 1 index type /filetype eq or {
|
|
% Use length for any files or reading data from any source.
|
|
1 index /Length knownoget not { 0 } if
|
|
} {
|
|
0 % Otherwise length of 0 for whole string
|
|
} ifelse
|
|
2 index /IDFlag known { pop } { () /SubFileDecode filter } ifelse
|
|
} {
|
|
applyfilters
|
|
} ifelse
|
|
} ifelse
|
|
% Stack: readdata? dict file
|
|
exch pop exch pop
|
|
} bind def
|
|
|
|
% ============================ Name/number trees ============================ %
|
|
|
|
/nameoget { % <nametree> <key> nameoget <obj|null>
|
|
exch /Names exch .treeget
|
|
} bind def
|
|
|
|
/numoget { % <numtree> <key> numoget <obj|null>
|
|
exch /Nums exch .treeget
|
|
} bind def
|
|
|
|
/.treeget { % <key> <leafkey> <tree> .treeget <obj|null>
|
|
dup /Kids knownoget {
|
|
exch pop .branchget
|
|
} {
|
|
exch get .leafget
|
|
} ifelse
|
|
} bind def
|
|
|
|
/.branchget { % <key> <leafkey> <kids> .branchget <obj|null>
|
|
dup length 0 eq {
|
|
pop pop pop null
|
|
} {
|
|
dup length -1 bitshift 2 copy oget
|
|
% Stack: key leafkey kids mid kids[mid]
|
|
dup /Limits oget aload pop
|
|
% Stack: key leafkey kids mid kids[mid] min max
|
|
6 index lt {
|
|
pop pop
|
|
1 add 1 index length 1 index sub getinterval .branchget
|
|
} {
|
|
5 index gt {
|
|
pop
|
|
0 exch getinterval .branchget
|
|
} {
|
|
exch pop exch pop .treeget
|
|
} ifelse
|
|
} ifelse
|
|
} ifelse
|
|
} bind def
|
|
|
|
/.leafget { % <key> <pairs> .leafget <obj|null>
|
|
dup length 2 eq {
|
|
dup 0 get 2 index eq { 1 oget } { pop null } ifelse
|
|
exch pop
|
|
} {
|
|
dup length -1 bitshift -2 and 2 copy oget
|
|
% Stack: key pairs mid pairs[mid]
|
|
3 index gt { 0 exch } { 1 index length 1 index sub } ifelse
|
|
getinterval .leafget
|
|
} ifelse
|
|
} bind def
|
|
|
|
end % pdfdict
|
|
.setglobal
|