Edit File: pdf_base.ps
% Copyright (C) 2001-2018 Artifex Software, Inc. % 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. % % Refer to licensing information at http://www.artifex.com or contact % Artifex Software, Inc., 1305 Grant Avenue - Suite 200, Novato, % CA 94945, U.S.A., +1(415)492-9861, for further information. % % pdf_base.ps % Basic parser for PDF reader. % This handles basic parsing of the file (including the trailer % and cross-reference table), as well as objects, object references, % streams, and name/number trees; it doesn't include any facilities for % making marks on the page. /.setlanguagelevel where { pop 2 .setlanguagelevel } if .currentglobal //true .setglobal pdfdict begin % Define the name interpretation dictionary for reading values. /valueopdict mark (<<) cvn { mark } bind executeonly % don't push an actual mark! (>>) cvn { { .dicttomark } stopped { ( **** Error: File has an unbalanced >> \(close dictionary\).\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror } if } bind executeonly ([) cvn { mark } bind executeonly % ditto (]) cvn dup load % /true true % see .pdfexectoken below % /false false % ibid. % /null null % ibid. /F dup cvx % see Objects section below /R dup cvx % see Objects section below /stream dup cvx % see Streams section below .dicttomark readonly def % ------ Utilities ------ % % Define a scratch string. The PDF language definition says that % no line in a PDF file can exceed 255 characters, but this string % is also used to search for %PDF-, which needs 1024 characters. /pdfstring 1024 string def % Handle the PDF 1.2 #nn escape convention when reading from a file. % This should eventually be done in C. /.pdffixname { % <execname> .pdffixname <execname'> PDFversion 1.2 ge { dup .namestring (#) search { name#escape cvn exch pop } { pop } ifelse } if } bind executeonly def /name#escape % <post> <(#)> <pre> name#escape <string> { exch pop 1 index 2 () /SubFileDecode filter dup (x) readhexstring % Stack: post pre stream char t/f not { % tolerate, but complain about bad syntax pop closefile (#) concatstrings exch ( **** Error: Invalid hex following '#' name escape, using literal '#' in name.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror } { exch closefile concatstrings exch 2 1 index length 2 sub getinterval } ifelse (#) search { name#escape } if concatstrings } bind executeonly def /num-chars-dict mark (0123456789-.) {dup} forall .dicttomark readonly def % Execute a file, interpreting its executable names in a given % dictionary. The name procedures may do whatever they want % to the operand stack. /.pdftokenerror { % <count> <opdict> <errtoken> .pdftokenerror - BXlevel 0 le { ( **** Error: Unknown operator: ') pdfformaterror dup =string cvs pdfformaterror (') pdfformaterror % Attempt a retry scan of the element after changing to PDFScanInvNum << /PDFScanInvNum //true >> setuserparams =string cvs token pop exch pop dup type dup /integertype eq exch /realtype eq or { exch pop exch pop (, processed as number, value: ) pdfformaterror dup =string cvs pdfformaterror (\n) pdfformaterror << /PDFScanInvNum //null >> setuserparams % reset to default scanning rules //false % suppress any stack cleanup } { % error was non-recoverable with modified scanning rules, continue. dup type /nametype eq { //true 1 index .namestring { //num-chars-dict exch known and } forall { % perhaps, it's a malformed number. PDFSTOPONERROR {//true}{ pop pop pop 0 //false ( looks like a malformed number, replacing with 0.) pdfformaterror } ifelse } { //true % punt } ifelse } { //true % punt } ifelse (\n) pdfformaterror } ifelse } { //true } ifelse { % clean up the operand stack if this was non-recoverable pop pop count exch sub { pop } repeat % pop all the operands } if ( Output may be incorrect.\n) pdfformaterror } bind executeonly def currentdict /num-chars-dict .undef /.pdfexectoken { % <count> <opdict> <exectoken> .pdfexectoken ? PDFDEBUG { //pdfdict /PDFSTEPcount known not { //pdfdict /PDFSTEPcount 1 .forceput } executeonly if PDFSTEP { //pdfdict /PDFtokencount 2 copy .knownget { 1 add } { 1 } ifelse .forceput PDFSTEPcount 1 gt { //pdfdict /PDFSTEPcount PDFSTEPcount 1 sub .forceput } executeonly { dup ==only ( step # ) print PDFtokencount =only ( ? ) print flush 1 //false .outputpage (%stdin) (r) file 255 string readline { token { exch pop //pdfdict /PDFSTEPcount 3 -1 roll .forceput } executeonly { //pdfdict /PDFSTEPcount 1 .forceput } executeonly ifelse % token } { pop /PDFSTEP //false def % EOF on stdin } ifelse % readline } ifelse % PDFSTEPcount > 1 } executeonly { dup ==only () = flush } ifelse % PDFSTEP } executeonly if % PDFDEBUG 2 copy .knownget { exch pop exch pop exch pop exec } { % Normally, true, false, and null would appear in opdict % and be treated as "operators". However, there is a % special fast case in the PostScript interpreter for names % that are defined in, and only in, systemdict and/or % userdict: putting these three names in the PDF dictionaries % destroys this property for them, slowing down their % interpretation in all PostScript code. Therefore, we % check for them explicitly here instead. dup dup dup /true eq exch /false eq or exch /null eq or { exch pop exch pop //systemdict exch get } { % Hackish fix to detect missing whitespace after "endobj". Yet another % problem that (you guessed it!) Adobe Acrobat ignores silently dup .namestring (endobj) anchorsearch { ( **** Error: Missing whitespace after 'endobj'.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror pop pop pop exch pop /endobj get exec } { %% First, lets try and see if this 'might' be a broken number %% we look for 0-9 as well as '.' ',' and '-' to permit those %% locales in which the separator is a comma, as well as negative %% numbers. We've seena t least one tool replace '0' with '-' *sometimes* true exch dup length 1 sub 0 1 3 -1 roll { 1 index exch get dup 44 lt { pop exch pop false exch exit }{ dup 57 gt { pop exch pop false exch exit }{ dup 47 eq { pop exch pop false exch exit }{ pop } ifelse } ifelse } ifelse } for pop { %% If it looks like a number, try to deal with it as such PDFSTOPONERROR { dup .pdftokenerror }{ dup {.pdftokenerror} stopped } ifelse { pop %% But if it fails, fall back to converting into a anem. %% This will propagate through and cause different %% fallback code to try and take care ot if. cvlit exch pop exch pop }{ exch pop } ifelse }{ %% Doesn't look like a number, convert it into a name cvlit exch pop exch pop } ifelse } ifelse } ifelse } ifelse } bind executeonly odef /PDFScanRules_true << /PDFScanRules //true >> def /PDFScanRules_null << /PDFScanRules //null >> def /.pdfrun { % <file> <opdict> .pdfrun - % Construct a procedure with the stack depth, file and opdict % bound into it. 1 index cvlit % file <<>> file count 2 sub % file <<>> file cnt 3 1 roll mark % file cnt <<>> file [ /PDFScanRules .getuserparam //null eq { //PDFScanRules_true { setuserparams } 0 get % force PDF scanning mode mark 7 4 roll } { mark 5 2 roll % file [ [ cnt <<>> file } ifelse { % Stack: ..operands.. count opdict file { token } stopped { dup type /filetype eq { pop } if pop pop stop } if { dup type /nametype eq { dup xcheck { .pdfexectoken } { .pdffixname exch pop exch pop PDFDEBUG { PDFSTEPcount 1 le { dup ==only ( ) print flush } if } if } ifelse } { exch pop exch pop PDFDEBUG { PDFSTEPcount 1 le { dup ==only ( ) print flush } if } if } ifelse } { pop pop exit } ifelse } aload pop .packtomark cvx % file [ {cnt <<>> file ... } { loop } 0 get 2 packedarray cvx % file [ { {cnt <<>> file ... } loop } PDFSTOPONERROR { {exec //false} } { {stopped} } ifelse aload pop % file [ { {cnt <<>> file ... } loop } stopped /PDFScanRules .getuserparam //null eq { //PDFScanRules_null { setuserparams } 0 get % reset PDF scannig mode if it was off } if /PDFsource PDFsource % file [ { {cnt <<>> file ... } loop } stopped /PDFsource PDFsource { store { /StreamRunAborted //true store ( **** Error reading a content stream. The page may be incomplete.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror } if } aload pop % file [ { {cnt <<>> file ... } loop } stopped /PDFsource PDFsource store {...} if .packtomark cvx % file { { {cnt <<>> file ... } loop } stopped /PDFsource PDFsource store {...} if} /PDFsource 3 -1 roll store % {...} exec } bind executeonly def % Execute a file, like .pdfrun, for a marking context. % This temporarily rebinds LocalResources and DefaultQstate. /.pdfruncontext { % <resdict> <file> <opdict> .pdfruncontext - /.pdfrun load LocalResources DefaultQstate /LocalResources 7 -1 roll store /DefaultQstate qstate store 3 .execn /DefaultQstate exch store /LocalResources exch store } bind executeonly def % Get the depth of the PDF operand stack. The caller sets pdfemptycount % before calling .pdfrun or .pdfruncontext. It is initially set by % pdf_main, and is also set by any routine which changes the operand % stack depth (currently .pdfpaintproc, although there are other callers % of .pdfrun{context} which have not been checked for opstack depth. /.pdfcount { % - .pdfcount <count> count pdfemptycount sub } bind executeonly def % Read a token, but simply return false (no token read) in the case of an % error. This is messy because 'token' either may or may not pop its operand % if an error occurs, and because the return values are different depending % on whether the source is a file or a string. To avoid closing the file % check for '{' before trying 'token'. /token_nofail_dict mark ( ) { dup ( ) readstring pop pop } bind executeonly (\t) 1 index (\r) 1 index (\n) 1 index (\000) 1 index ({) { //null //true exit } bind executeonly .dicttomark def /token_nofail { % <file|string> token_nofail false % <file> token_nofail <token> true % <string> token_nofail <post> <token> true dup type /filetype eq { { dup ( ) .peekstring not { ({) } if //token_nofail_dict exch .knownget not { //null 1 index { token } .internalstopped exit } if exec } loop { % stack: source null [source] //null ne { pop } if pop //false } { % stack: source null ([post] token true | false) { 3 1 roll pop pop //true } { pop pop //false } ifelse } ifelse } { //null 1 index % stack: source null source { token } .internalstopped { % stack: source null [source] //null ne { pop } if pop //false } { % stack: source null ([post] token true | false) { 4 2 roll pop pop //true } { pop pop //false } ifelse } ifelse } ifelse } bind executeonly def currentdict /token_nofail_dict .undef % ================================ Objects ================================ % % We keep track of PDF objects using the following PostScript variables: % % Generations (string): Generations[N] holds 1+ the current % generation number for object number N. (As far as we can tell, % this is needed only for error checking.) For free objects, % Generations[N] is 0. % % Objects (array): If object N is loaded, Objects[N] is the actual % object; otherwise, Objects[N] is an executable integer giving % the file offset of the object's location in the file. If % ObjectStream[N] is non-zero then Objects[N] contains the index % into the object stream instead of the file offset of the object. % % ObjectStream (array): If object N is in an object stream then % ObjectStream[N] holds the object number of the object stream. % Otherwise ObjectStream[N] contains 0. If ObjectStream[N] % is non-zero then Objects[N] contains the index into the object % stream. % % GlobalObjects (dictionary): If object N has been resolved in % global VM, GlobalObjects[N] is the same as Objects[N] % (except that GlobalObjects itself is stored in global VM, % so the entry will not be deleted at the end of the page). % % IsGlobal (string): IsGlobal[N] = 1 iff object N was resolved in % global VM. This is an accelerator to avoid having to do a % dictionary lookup in GlobalObjects when resolving every object. % Initialize the PDF object tables. /initPDFobjects { % - initPDFobjects - /ObjectStream 0 array def /Objects 0 array def /Generations 0 string def .currentglobal //true .setglobal /GlobalObjects 20 dict def .setglobal /IsGlobal 0 string def } bind executeonly def % Grow the tables to a specified size. /growPDFobjects { % <minsize> growPDFobjects - dup ObjectStream length gt { dup ObjectStream exch array dup 3 1 roll copy pop /ObjectStream exch def } if dup Objects length gt { dup Objects exch array dup 3 1 roll copy pop /Objects exch def } if dup Generations length gt { dup Generations exch string dup 3 1 roll copy pop /Generations exch def } if dup IsGlobal length gt { dup IsGlobal exch string dup 3 1 roll copy pop /IsGlobal exch def } if pop } bind executeonly def % We represent an unresolved object reference by a procedure of the form % {obj# gen# resolveR}. This is not a possible PDF object, because PDF has % no way to represent procedures. Since PDF in fact has no way to represent % any PostScript object that doesn't evaluate to itself, we can 'force' % a possibly indirect object painlessly with 'exec'. % Note that since we represent streams by executable dictionaries % (see below), we need both an xcheck and a type check to determine % whether an object has been resolved. /resolved? { % <object#> resolved? <value> true % <object#> resolved? false Objects 1 index get dup xcheck { % Check if executable dup type /integertype eq { % Check if an integer % Check whether the object is in GlobalObjects. pop IsGlobal 1 index get 0 eq { % 0 --> Not in GlabalObjects pop //false % The object is not resolved } { % The object is in GlobalObjects % Update Objects from GlobalObjects PDFDEBUG { (%Global=>local: ) print dup //== exec } if GlobalObjects 1 index get dup Objects 4 1 roll put //true } ifelse } { % Else object is executable but not integer exch pop //true % Therefore must be executable dict. (stream) } ifelse } { % Else object is not executable. exch pop //true % Therefore it must have been resolved. } ifelse } bind executeonly def /oforce /exec load def /oget { % <array> <index> oget <object> % <dict> <key> oget <object> % Before release 6.20, this procedure stored the resolved % object back into the referring slot. In order to support % PDF linearization, we no longer do this. get oforce } bind executeonly def /oforce_array { % <array> oforce_array <array> [ exch { oforce } forall ] } bind executeonly def /oforce_elems { % <array> oforce_elems <first> ... <last> { oforce } forall } bind executeonly def %% Safe recursion maintain a dicitonary in which we record all the object numbers %% of objects which we resolve. Whenever it resolves a new one, it checks all the %% existing ones to see if its already present, in which case we assume recursion %% has taken place. Whenever this procedure calls itself it copies the existing %% dictionary, and throws it away afterwards. This means that we won't falsely %% detect recursion if two elements at the same level indirect to the same %% object. /safe_recursive { % <<recursion dict>> <any> oforce_recursive <recursion dict> <any> dup type dup /arraytype eq exch /packedarraytype eq or { dup rcheck { % protect tint transform functions, etc. dup length 3 eq { dup 2 get /resolveR eq { dup 0 get % <recursion dict> {x y resolveR} x dup % <recursion dict> {x y resolveR} x x 3 index exch known { ( **** Error: detected circular reference in object number ) pdfformaterror pdfstring cvs pdfformaterror (\n) pdfformaterror pop //null } { dup 3 index % <recursion dict> {x y resolveR} x x <recursion dict> 3 1 roll put % <recursion dict> {x y resolveR} } ifelse } if } if oforce % but dereference {1 0 R} dup type dup /arraytype eq exch /packedarraytype eq or { [ exch 2 index <<>> copy exch { safe_recursive exch } forall pop] } { dup type /dicttype eq { << exch 2 index <<>> copy exch { 3 -1 roll exch safe_recursive 3 -1 roll oforce 3 1 roll exch } forall pop>> } if } ifelse } if } { dup type /dicttype eq { << exch 2 index <<>> copy exch { 3 -1 roll exch safe_recursive 3 -1 roll oforce 3 1 roll exch } forall pop>> } if } ifelse } bind executeonly def /oforce_recursive { << >> exch safe_recursive exch pop } bind executeonly def % A null value in a dictionary is equivalent to an omitted key; % we must check for this specially. /knownoget { % <dict> <key> knownoget <value> true % <dict> <key> knownoget false % See oget above regarding this procedure. .knownget { oforce dup //null eq { pop //false } { //true } ifelse } { //false } ifelse } bind executeonly def % See /knownoget above. /oknown { % <dict> <key> oknown <bool> .knownget { oforce //null ne } { //false } ifelse } bind executeonly def /knownogetdict { % <dict> <key> knownogetdict <dict> true % <dict> <key> knownogetdict false //knownoget exec dup { 1 index type /dicttype ne { pop pop //false } if } if } bind executeonly def % PDF 1.1 defines a 'foreign file reference', but not its meaning. % Per the specification, we convert these to nulls. /F { % <file#> <object#> <generation#> F <object> % Some PDF 1.1 files use F as a synonym for f! .pdfcount 3 lt { f } { pop pop pop //null } ifelse } bind executeonly def % Verify the generation number for a specified object % Note: The values in Generations is the generation number plus 1. % If the value in Generations is zero then the object is free. /checkgeneration { % <object#> <generation#> checkgeneration <object#> <OK> Generations 2 index get 1 sub 1 index eq { % If generation # match ... pop //true % Then return true } { % Else not a match ... QUIET not { % Create warning message if not QUIET Generations 2 index get 0 eq { % Check if object is free ... ( **** Warning: reference to free object: ) 2 index =string cvs concatstrings ( ) concatstrings % put obj # exch =string cvs concatstrings ( R\n) concatstrings % put gen # } { ( **** Warning: wrong generation: ) 2 index =string cvs concatstrings ( ) concatstrings % put obj # exch =string cvs concatstrings % put gen # (, xref gen#: ) concatstrings 1 index Generations % put xref gen # exch get 1 sub =string cvs concatstrings (\n) concatstrings } ifelse pdfformatwarning % Output warning message } { % Else QUIET ... pop % Pop generation number } ifelse % We should return false for an incorrect generation number, however % we are simply printing a warning and then returning true. This makes % Ghostscript tolerant of of bad generation numbers. //true } ifelse } bind executeonly def /R { % <object#> <generation#> R <object> %% Parameter validation; this should not be required but we have found files %% (Bug 697351) which are corrupted in ways that mean we see a 'R' in a stream %% even though it is not an indirect object reference. Because a stream %% may reference objetcs which have not been resolved, we cannot simply %% 'undef' teh R operator, the only solution is to have it chekc the %% types of its operands. This is poterntially slow of course, we may %% need to remove this in future if the performance penalty is too great. %% We cannot slow down all files significantly purely to work-around %% files which are invalid. 1 index type /integertype eq 1 index type /integertype eq and { /resolveR cvx 3 packedarray cvx } { ( **** Error: indirect object reference \(R\) encountered with invalid arguments.) pdfformaterror ( Output may be incorrect.\n) pdfformaterror } ifelse } bind executeonly def % If we encounter an object definition while reading sequentially, % we just store it away and keep going. /objopdict mark valueopdict { } forall /endobj dup cvx .dicttomark readonly def /obj { % <object#> <generation#> obj <object> PDFfile objopdict .pdfrun } bind executeonly def /endobj { % <object#> <generation#> <object> endobj <object> %% If we have a stream wioth a broken endstream we can get here without %% an object definition on nthe stack. If we simply pop the 'extraneous' %% data we will break the stream definition and throw an error. So we look %% to see if this appears to be this specific case. 2 index type /marktype eq 2 index type /marktype eq or { { dup type /marktype eq { exit }{ pop }if }loop }{ { 2 index type /integertype ne 2 index type /integertype ne or { count 3 gt { ( **** Error: obj definition followed by multiple tokens, attempting to recover.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror pop } { //null ( **** Error: ignoring obj followed by multiple tokens.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror exit } ifelse } { exit } ifelse } loop 3 1 roll % Read the xref entry if we haven't yet done so. % This is only needed for generation # checking. 1 index resolved? { pop } if checkgeneration { % The only global objects we bother to save are % (resource) dictionaries. 1 index dup gcheck exch type /dicttype eq and { PDFDEBUG { (%Local=>global: ) print dup //== exec } if GlobalObjects 1 index 3 index put IsGlobal 1 index 1 put } if Objects exch 2 index put } { pop pop //null } ifelse }ifelse } bind executeonly def % When resolving an object reference in an object stream, we stop at % the end of file. Note: Objects in an object stream do not have either % a starting 'obj' or and ending 'endobj'. /resolveobjstreamopdict mark valueopdict { } forall (%%EOF) cvn { exit } bind executeonly /endobj { % bug 689795 ( **** Error: Objects in an object stream should not have 'endobj'.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror } bind executeonly .dicttomark readonly def % Note: This version of this function is not currently being used. % 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 /First get % Save location of first object onto the stack 1 index /N get % Save number of objects onto the stack 2 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 % Create two arrays to hold object numbers and stream location 1 index array % Array for holding object number 2 index array % Array for holding stream object location % Get the object numbers and locations. 0 1 5 index 1 sub { % Loop and collect obj # and locations % Stack: objstreamdict First N objectstream [obj#] [loc] index 2 index 1 index % Setup to put obj# into object number array 5 index token pop put % Get stream, then get obj# and put into array 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 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 put % 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 put % Put object into Objects array } if pop pop pop pop % Clear stack } bind executeonly def /no_debug_dict << /PDFDEBUG //false >> readonly def % Resolve all objects in an object stream /resolveobjectstream { % <object stream #> resolveobjectstream - PDFDEBUG { (%Resolving object stream: ) print } if dup 0 resolveR % Get the objectstream dict, all objstrms use 0 as the gen # dup /Type get /ObjStm ne { % Verify type is object stream ( **** Error: Incorrect Type in object stream dictionary.\n) pdfformaterror ( Output may be incorrect.\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: strm# 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 { //no_debug_dict begin } if % Read the data for all objects. We check to see if we get % the number of objects that we expect. % Stack: strm# objstreamdict N objectstream [obj#] PDFDEBUG mark 3 -1 roll % Get objectstream count 4 index add % Determine stack depth with objects 3 1 roll resolveobjstreamopdict .pdfrun % Get PDF objects count counttomark 1 add index ne { % Check stack depth ( **** Error: Incorrect object count in object stream.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror /resolveobjectstream cvx /rangecheck signalerror } if % We have the object data counttomark array astore % Put objects into an array exch pop exch pop % Remove mark and count currentdict //no_debug_dict eq { end } if % Restore debug context % Save the objects into Objects 0 1 2 index length 1 sub { % Loop through all objects % Stack: strm# objstreamdict N [obj#] [objects] loopindex dup 3 index exch get % Get our current object number % Stack: strm# objstreamdict N [obj#] [objects] loopindex obj# dup ObjectStream exch get 7 index eq { 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 put } ifelse } { pop % Ignore old object; remove object number. } ifelse pop % Remove loop index } for pop pop pop pop pop % Remove strm# objstream, N, (obj#], and [objects] } bind executeonly def currentdict /no_debug_dict undef % When resolving an object reference, we stop at the endobj or endstream. /resolveopdict mark valueopdict { } forall /xref { % Bug 697761 ( **** Error: Encountered 'xref' while expecting 'endobj'.\n) pdfformaterror ( Treating this as a missing 'endobj', output may be incorrect.\n) pdfformaterror endobj exit } bind executeonly /endstream { endobj exit } bind /endobj { endobj exit } bind /endjobj { % Bug 689876. ( **** Error: Operator 'endobj' is misspelled as 'endjobj'.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror endobj exit } bind executeonly /enbobj { % Bug 690397. ( **** Error: Operator 'endobj' is misspelled as 'enbobj'.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror endobj exit } bind executeonly /obj { % OmniForm generates PDF file with endobj missing in some % objects. AR ignores this. So we have to do it too. ( **** Error: Encountered 'obj' while expecting 'endobj'.\n) pdfformaterror ( Treating this as a missing 'endobj', output may be incorrect.\n) pdfformaterror pop pop endobj exit } bind executeonly .dicttomark readonly def /resolveR { % <object#> <generation#> resolveR <object> 1 index 3 1 roll % copy the object for the code after pdf_run_resolve (may store it) PDFDEBUG { PDFSTEPcount 1 le { (%Resolving: ) print 2 copy 2 array astore //== exec } if } if 1 index dup 0 le exch NumObjects ge or { ( **** Error: Considering object with an invalid number ) 2 index 20 string cvs concatstrings ( as null.\n) concatstrings pdfformaterror ( Output may be incorrect.\n) pdfformaterror pop pop //null } { 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 get % Get location of object from xref 3 1 roll checkgeneration { % Verify the generation number % Stack: savepos objpos obj# ObjectStream 1 index get dup 0 eq { % Check if obj in not an objstream pop exch PDFoffset add PDFfile exch setfileposition PDFfile token pop 2 copy ne { ( **** Error: Unrecoverable error in xref!\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror /resolveR cvx /rangecheck signalerror } if pop PDFfile token pop PDFfile token pop /obj ne { ( **** Error: Unrecoverable error in xref!\n) pdfformaterror ( Output may be incorrect.\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 } ifelse dup type /dicttype eq % For dictionaries only { dup /Type known % make sure the dictionary has a type { %% We must not add to *all* dictionaries, because some of them are handled by %% executing all the key/value pairs, and adding a integer causes problems %% Since we only use this number for font identification, or checking self-references, %% we only need it for dictionaries with a Type, and these are always handled more carefully. dup 3 -1 roll /.gs.pdfobj# exch put } {exch pop} ifelse } {exch pop} ifelse } bind executeonly 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 /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 % Skip spaces till \n or a non-space character is found. //false { PDFfile read pop dup 32 eq { pop //true or } { exit } ifelse } loop dup 13 eq { pop PDFfile read pop } if 10 ne { PDFfile dup fileposition 1 sub setfileposition //true or } if { ( **** Error: stream operator isn't terminated by valid EOL.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror } if dup /FilePosition PDFfile fileposition put PDFDEBUG { PDFSTEPcount 1 le { (%FilePosition: ) print dup /FilePosition get //== exec } 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 knownoget { 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 } if } { 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 { ( **** Error: Unexpected EOF in stream!\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror /stream cvx /rangecheck signalerror } if 1 index exch /File exch put } ifelse PDFsource token_nofail not { //null } if dup /endobj eq { % Another case that Acrobat Reader handles -- 'endobj' without 'endstream'. ( **** Error: stream missing 'endstream'.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror pop /endstream % fake a valid endstream } if /endstream ne { ( **** Error: stream Length incorrect.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror dup /Length undef % prevent the use of the incorrect length. %% Bug #696560 If we get a stream whose length is incorrect we cannot %% safely *assume* it has an object definition as we can get here when %% reading an XRef stream, and in that case we will not have the object %% and generation numbers on the stack! %% So before we call endobj and exit pdfrun, try and see if ths looks like %% a regular object or not. If it isn't then don't try and ahndle it as %% one, just return the object. count 3 ge { 1 index type /integertype eq 2 index type /integertype eq and { cvx endobj exit % exit from .pdfrun now. } if } if } { PDFsource (??) .peekstring pop (>>) eq { % Bug 690161, sample #1 ( **** Error: Spurious '>>' after 'endstream' ignored.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror PDFsource (12) readstring pop pop } if } ifelse cvx } bind executeonly def /endstream { exit } bind executeonly 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 { oforce_recursive exch 2 index exch knownoget { dup length 0 eq { pop //false } { //true } ifelse } { //false } ifelse { % Both filters and parameters. oforce_recursive 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 executeonly 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 RepiredAnError exch ( **** ERROR: Unable to process ) pdfformaterror 64 string cvs pdfformaterror ( data. Page will be missing data.\n) pdfformaterror /RepairedAnError exch store /Repaired exch store % restore the previous "Repaired" state % provide a filter that returns EOF (no data) /.EOFDecode } ifelse } bind executeonly def /pdf_rules_dict << /PDFRules //true >> readonly def % Add PDF option to ASCII85Decode filter % <source> <name> add_A85_param <source> <dict'> <name> % <source> <dict> <name> add_A85_param <source> <dict'> <name> /add_A85_param { dup /ASCII85Decode eq { 1 index type /dicttype eq { exch dup length 1 add dict copy dup /PDFRules //true put exch } { //pdf_rules_dict exch } ifelse } if } bind executeonly def currentdict /pdf_rules_dict undef /applyfilters { % <parms> <source> <filternames> applyfilters <stream> 2 index //null eq { { filtername add_A85_param filter } } { dup length 3 index length ne %% compare lengths of DecodeParmas and Filter arrays { %% if they aren't the same, ignore the decode params ( **** Error: ignoring stream /DecodeParams array as its length is different to the Filters array.\n) pdfformaterror ( Output may be incorrect.\n) pdfformaterror 3 -1 roll pop //null 3 1 roll { filtername add_A85_param filter } } { { % Stack: parms source filtername 2 index 0 oget dup type /dicttype ne { pop } { exch filtername dup /JBIG2Decode eq { exch jbig2cachectx exch } if } ifelse add_A85_param filter exch dup length 1 sub 1 exch getinterval exch } } ifelse } ifelse forall exch pop } bind executeonly 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 { % make global ctx PDFfile fileposition exch % resolvestream is not reentrant //true resolvestream % stack after: PDFfileposition -file- % Read the data in a loop until EOF to so we can move the strings into a bytestring [ { counttomark 1 add index 60000 string readstring not { exit } if } loop ] exch pop 0 1 index { length add } forall % compute the total length % now copy the data from the array of strings into a bytestring .bytestring exch 0 exch { 3 copy putinterval length add } forall pop .jbig2makeglobalctx PDFfile 3 -1 roll setfileposition 1 index exch /.jbig2globalctx exch put } if } bind executeonly 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 /Length knownoget { 0 eq } { //false } ifelse { () 0 () /SubFileDecode filter } { dup /FilePosition .knownget { 1 index /File get exch setfileposition } if % Stack: readdata? dict /DecodeParms /Filter filterparms % Stack: readdata? dict parms filternames 2 index /File .knownget not { ( **** Error: Stream object is missing the stream data.\n) ( Output may be incorrect.\n) pdfformaterror pdfformaterror () } if exch % Stack: readdata? dict parms file/string filternames dup length 0 eq { % All the PDF filters have EOD markers, but in this case % there is no specified filter. exch dup type /filetype eq 5 index or { % Use length for any files or reading data from any source. 3 index /Length knownoget not { 0 } if } { 0 % Otherwise length of 0 for whole string } ifelse 4 index /IDFlag known { pop } { () /SubFileDecode filter } ifelse exch pdf_decrypt_stream % add decryption if needed pop exch pop } { % Stack: readdata? dict parms source filternames exch 3 index /Length knownoget { () /SubFileDecode filter } if exch pdf_decrypt_stream % add decryption if needed applyfilters } ifelse } ifelse } ifelse % Stack: readdata? dict file exch pop exch pop } bind executeonly def % ============================ Name/number trees ============================ % /nameoget { % <nametree> <key> nameoget <obj|null> exch /Names exch .treeget } bind executeonly def /numoget { % <numtree> <key> numoget <obj|null> exch /Nums exch .treeget } bind executeonly def /.treeget { % <key> <leafkey> <tree> .treeget <obj|null> dup /Kids knownoget { exch pop .branchget } { exch oget .leafget } ifelse } bind executeonly 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 executeonly 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 executeonly def % The following variants return tree entry whose key is closest but % less or equal to the given key. /numogetle { % <numtree> <key> numogetle <key obj true|false> exch /Nums exch .treegetle } bind executeonly def /.treegetle { % <key> <leafkey> <tree> .treegetle <key obj true|false> dup /Kids knownoget { exch pop .branchgetle } { exch oget .leafgetle } ifelse } bind executeonly def /.branchgetle { % <key> <leafkey> <kids> .branchgetle <key obj true|false> dup length 0 eq { pop pop pop false } { dup length -1 bitshift 2 copy oget dup /Limits oget aload pop % Stack: key leafkeyb kids mid kids[mid] min max 6 index ge { 5 index le { exch pop exch pop .treegetle } { pop 0 exch getinterval .branchgetle } ifelse } { pop 2 index length 2 index sub 1 gt { pop 1 index length 1 index sub getinterval .branchgetle } { exch pop exch pop .treegetle } ifelse } ifelse } ifelse } bind executeonly def /.leafgetle { % <key> <pairs> .leafget <obj|null> dup length 2 eq { dup 0 get 2 index le { exch pop aload pop true } { pop pop false } ifelse } { 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 .leafgetle } ifelse } bind executeonly def end % pdfdict .setglobal