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Generalise last commit to xref parsing and reconstruction
Tests use a modified dangling-bad-xref.pdf.
This commit is contained in:
m-holger
parent
405f3765c5
commit
8753ffe335
@ -463,9 +463,8 @@ QPDF::fixDanglingReferences(bool force)
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size_t
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QPDF::getObjectCount()
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{
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// This method returns the next available indirect object number. makeIndirectObject uses it for
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// this purpose. After fixDanglingReferences is called, all objects in the xref table will also
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// be in obj_cache.
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// This method returns the highest used indirect object number. Calling this method will resolve
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// all objects.
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return toS(m->objects.last_id());
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}
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@ -171,18 +171,28 @@ Xref_table::initialize()
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initialized_ = true;
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}
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// Remove any dangling reference picked up while parsing the xref table.
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// Remove any dangling reference picked up while parsing or reconstructing the xref table from the
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// object table.
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void
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Xref_table::prepare_obj_table()
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{
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for (auto it = objects.table.begin(), end = objects.table.end(); it != end;) {
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if (type(it->first, it->second.gen)) {
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++it;
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} else {
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if (it->second.unconfirmed && !type(it->first, it->second.gen)) {
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it->second.object->make_null();
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it = objects.table.erase(it);
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} else {
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it->second.unconfirmed = false;
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++it;
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}
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}
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for (auto& [id_gen, obj]: objects.unconfirmed_objects) {
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if (type(id_gen.first, id_gen.second)) {
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objects.update_table(id_gen.first, id_gen.second, obj);
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} else {
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obj->make_null();
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}
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}
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objects.unconfirmed_objects.clear();
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}
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void
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@ -204,6 +214,8 @@ Xref_table::reconstruct(QPDFExc& e)
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};
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reconstructed_ = true;
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bool called_during_resolve_attempt = initialized_;
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initialized_ = false;
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warn_damaged("file is damaged");
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qpdf.warn(e);
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@ -280,7 +292,7 @@ Xref_table::reconstruct(QPDFExc& e)
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if (item.type() != 1) {
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continue;
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}
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auto oh = objects.get(i, item.gen());
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QPDFObjectHandle oh{objects.get_when_uncertain(i, item.gen())};
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try {
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if (!oh.isStreamOfType("/XRef")) {
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continue;
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@ -319,8 +331,11 @@ Xref_table::reconstruct(QPDFExc& e)
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throw damaged_pdf("unable to find objects while recovering damaged file");
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}
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check_warnings();
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if (!initialized_) {
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initialized_ = true;
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prepare_obj_table();
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initialized_ = true;
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if (!called_during_resolve_attempt) {
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// We can't do the checks because we may try to resolve the object that triggered the
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// reconstruction.
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qpdf.getAllPages();
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check_warnings();
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if (qpdf.m->all_pages.empty()) {
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@ -1552,7 +1567,7 @@ QPDFObject*
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Objects::resolve(int id, int gen)
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{
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if (!unresolved(id, gen)) {
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return get(id, gen).getObjectPtr();
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return get_for_parser(id, gen, true).get();
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}
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auto og = QPDFObjGen(id, gen);
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@ -1835,6 +1850,9 @@ std::shared_ptr<QPDFObject>
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Objects::get_for_parser(int id, int gen, bool parse_pdf)
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{
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// This method is called by the parser and therefore must not resolve any objects.
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if (!xref.initialized() && parse_pdf) {
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return get_when_uncertain(id, gen);
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}
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auto iter = table.find(id);
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if (iter != table.end() && iter->second.gen == gen) {
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return iter->second.object;
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@ -1843,7 +1861,7 @@ Objects::get_for_parser(int id, int gen, bool parse_pdf)
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// id in table, different gen
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return QPDF_Null::create();
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}
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if (xref.type(id, gen) || !xref.initialized()) {
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if (xref.type(id, gen)) {
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return table.insert({id, {gen, QPDF_Unresolved::create(&qpdf, QPDFObjGen(id, gen))}})
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.first->second.object;
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}
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@ -1869,7 +1887,9 @@ Objects::get_when_uncertain(int id, int gen)
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e.gen = gen;
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if (!xref.type(id, gen)) {
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e.unconfirmed = true;
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return e.object = QPDF_Null::create(&qpdf, QPDFObjGen(id, gen));
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return e.object = xref.initialized()
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? QPDF_Null::create(&qpdf, QPDFObjGen(id, gen))
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: QPDF_Unresolved::create(&qpdf, QPDFObjGen(id, gen));
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} else {
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return e.object = QPDF_Unresolved::create(&qpdf, QPDFObjGen(id, gen));
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}
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@ -1889,7 +1909,8 @@ Objects::get_when_uncertain(int id, int gen)
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if (auto& j = unconfirmed_objects[{id, gen}]) {
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return j;
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} else {
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return j = QPDF_Null::create(&qpdf, QPDFObjGen(id, gen));
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return j = xref.initialized() ? QPDF_Null::create(&qpdf, QPDFObjGen(id, gen))
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: QPDF_Unresolved::create(&qpdf, QPDFObjGen(id, gen));
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}
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}
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@ -14,7 +14,7 @@ cleanup();
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my $td = new TestDriver('dangling-refs');
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my @dangling = (qw(minimal dangling-refs dangling-bad-xref));
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my @dangling = (qw(minimal dangling-refs dangling-bad-xref dangling-multiple-gen-bad-xref));
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my $n_tests = 2 * scalar(@dangling);
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foreach my $f (@dangling)
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BIN
qpdf/qtest/qpdf/dangling-multiple-gen-bad-xref-dangling-out.pdf
Normal file
BIN
qpdf/qtest/qpdf/dangling-multiple-gen-bad-xref-dangling-out.pdf
Normal file
Binary file not shown.
15
qpdf/qtest/qpdf/dangling-multiple-gen-bad-xref-dangling.out
Normal file
15
qpdf/qtest/qpdf/dangling-multiple-gen-bad-xref-dangling.out
Normal file
@ -0,0 +1,15 @@
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WARNING: dangling-multiple-gen-bad-xref.pdf: file is damaged
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WARNING: dangling-multiple-gen-bad-xref.pdf (object 7 0, offset 10000): expected n n obj
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WARNING: dangling-multiple-gen-bad-xref.pdf: Attempting to reconstruct cross-reference table
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new object: 12 0 R
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all objects
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1 3 R
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2 3 R
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3 0 R
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4 0 R
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5 0 R
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6 0 R
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7 0 R
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11 0 R
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12 0 R
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test 53 done
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118
qpdf/qtest/qpdf/dangling-multiple-gen-bad-xref.pdf
Normal file
118
qpdf/qtest/qpdf/dangling-multiple-gen-bad-xref.pdf
Normal file
@ -0,0 +1,118 @@
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%PDF-1.3
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%¿÷¢þ
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%QDF-1.0
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1 3 obj
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<<
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/Pages 2 3 R
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/Type /Catalog
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/Dangling 8 0 R
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/AlsoDangling [
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9 0 R
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<<
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/yes 2 5 R
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/no 10 0 R
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/nope 8 0 R
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>>
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]
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>>
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endobj
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2 3 obj
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<<
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/Count 1
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/Kids [
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3 0 R
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]
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/Type /Pages
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>>
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endobj
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%% Page 1
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3 0 obj
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<<
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/Contents 4 0 R
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/MediaBox [
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0
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0
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612
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792
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]
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/Parent 2 0 R
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/Resources <<
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/Font <<
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/F1 6 0 R
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>>
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/ProcSet 7 0 R
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>>
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/Type /Page
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>>
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endobj
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%% Contents for page 1
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4 0 obj
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<<
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/Length 5 0 R
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>>
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stream
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BT
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/F1 24 Tf
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72 720 Td
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(Potato) Tj
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ET
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endstream
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endobj
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5 0 obj
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44
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endobj
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6 0 obj
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<<
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/BaseFont /Helvetica
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/Encoding /WinAnsiEncoding
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/Name /F1
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/Subtype /Type1
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/Type /Font
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>>
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endobj
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7 0 obj
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[
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/PDF
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/Text
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]
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endobj
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11 0 obj
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[
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12 0 R
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2 4 R
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]
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endobj
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xref
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0 8
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0000000000 65535 f
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0000000025 00003 n
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0000000195 00003 n
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0000000277 00000 n
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0000000492 00000 n
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0000000591 00000 n
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0000000610 00000 n
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0000010000 00000 n
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trailer <<
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/Dangle [
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1 0 R
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1 6 R
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2 6 R
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2 0 R
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4 6 R
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]
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/Root 1 3 R
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/Size 8
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/ID [<7141a6cf32de469328cf0f51982b5f89><7141a6cf32de469328cf0f51982b5f89>]
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>>
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startxref
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803
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%%EOF
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