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https://github.com/qpdf/qpdf.git
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Refactor Xref_table::Entry
Replace QPDFXRefEntry with a std::variant of structs.
This commit is contained in:
m-holger
parent
6b9eb14c76
commit
a1b646fcca
@ -574,7 +574,7 @@ QPDF::Xref_table::reconstruct(QPDFExc& e)
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// Delete all references to type 1 (uncompressed) objects
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for (auto& iter: table) {
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if (iter.entry.getType() == 1) {
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if (iter.type() == 1) {
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iter = {};
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}
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}
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@ -638,12 +638,12 @@ QPDF::Xref_table::reconstruct(QPDFExc& e)
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qpdf_offset_t max_offset{0};
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// If there are any xref streams, take the last one to appear.
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int i = -1;
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for (auto const& [gen, entry]: table) {
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for (auto const& item: table) {
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++i;
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if (entry.getType() != 1) {
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if (item.type() != 1) {
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continue;
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}
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auto oh = qpdf.getObject(i, gen);
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auto oh = qpdf.getObject(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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@ -651,7 +651,7 @@ QPDF::Xref_table::reconstruct(QPDFExc& e)
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} catch (std::exception&) {
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continue;
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}
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auto offset = entry.getOffset();
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auto offset = item.offset();
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if (offset > max_offset) {
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max_offset = offset;
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trailer_ = oh.getDict();
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@ -1334,9 +1334,9 @@ QPDF::Xref_table::insert(int obj, int f0, qpdf_offset_t f1, int f2)
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}
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auto& entry = table[static_cast<size_t>(obj)];
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auto old_type = entry.entry.getType();
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auto old_type = entry.type();
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if (!old_type && entry.gen > 0) {
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if (!old_type && entry.gen() > 0) {
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// At the moment we are processing the updates last to first and therefore the gen doesn't
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// matter as long as it > 0 to distinguish it from an uninitialized entry. This will need
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// to be revisited when we want to support incremental updates or more comprhensive
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@ -1351,7 +1351,7 @@ QPDF::Xref_table::insert(int obj, int f0, qpdf_offset_t f1, int f2)
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return;
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}
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if (old_type && entry.gen >= new_gen) {
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if (old_type && entry.gen() >= new_gen) {
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QTC::TC("qpdf", "QPDF xref reused object");
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return;
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}
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@ -1360,11 +1360,11 @@ QPDF::Xref_table::insert(int obj, int f0, qpdf_offset_t f1, int f2)
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case 1:
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// f2 is generation
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QTC::TC("qpdf", "QPDF xref gen > 0", (f2 > 0) ? 1 : 0);
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entry = {f2, QPDFXRefEntry(f1)};
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entry = {f2, Uncompressed(f1)};
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break;
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case 2:
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entry = {0, QPDFXRefEntry(toI(f1), f2)};
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entry = {0, Compressed(toI(f1), f2)};
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break;
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default:
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@ -1400,19 +1400,18 @@ QPDF::Xref_table::show()
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{
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auto& cout = *qpdf.m->log->getInfo();
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int i = -1;
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for (auto const& [gen, entry]: table) {
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for (auto const& item: table) {
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++i;
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auto type = entry.getType();
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if (type) {
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cout << std::to_string(i) << "/" << std::to_string(gen) << ": ";
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switch (type) {
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if (item.type()) {
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cout << std::to_string(i) << "/" << std::to_string(item.gen()) << ": ";
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switch (item.type()) {
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case 1:
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cout << "uncompressed; offset = " << entry.getOffset() << "\n";
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cout << "uncompressed; offset = " << item.offset() << "\n";
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break;
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case 2:
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cout << "compressed; stream = " << entry.getObjStreamNumber()
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<< ", index = " << entry.getObjStreamIndex() << "\n";
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cout << "compressed; stream = " << item.stream_number()
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<< ", index = " << item.stream_index() << "\n";
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break;
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default:
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@ -1430,11 +1429,11 @@ QPDF::Xref_table::resolve()
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{
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bool may_change = !reconstructed_;
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int i = -1;
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for (auto& iter: table) {
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for (auto& item: table) {
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++i;
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if (iter.entry.getType()) {
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if (qpdf.isUnresolved(QPDFObjGen(i, iter.gen))) {
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qpdf.resolve(QPDFObjGen(i, iter.gen));
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if (item.type()) {
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if (qpdf.isUnresolved(QPDFObjGen(i, item.gen()))) {
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qpdf.resolve(QPDFObjGen(i, item.gen()));
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if (may_change && reconstructed_) {
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return false;
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}
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@ -3,6 +3,8 @@
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#include <qpdf/QPDF.hh>
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#include <variant>
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// Xref_table encapsulates the pdf's xref table and trailer.
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class QPDF::Xref_table
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{
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@ -34,54 +36,55 @@ class QPDF::Xref_table
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}
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// Returns 0 if og is not in table.
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int
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size_t
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type(QPDFObjGen og) const
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{
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if (og.getObj() >= toI(table.size())) {
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int id = og.getObj();
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if (id < 1 || static_cast<size_t>(id) >= table.size()) {
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return 0;
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}
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auto& e = table.at(toS(og.getObj()));
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return e.gen == og.getGen() ? e.entry.getType() : 0;
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auto& e = table[static_cast<size_t>(id)];
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return e.gen() == og.getGen() ? e.type() : 0;
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}
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// Returns 0 if og is not in table.
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int
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type(size_t id) const
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size_t
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type(size_t id) const noexcept
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{
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if (id >= table.size()) {
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return 0;
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}
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return table[id].entry.getType();
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return table[id].type();
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}
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// Returns 0 if og is not in table.
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qpdf_offset_t
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offset(QPDFObjGen og) const
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offset(QPDFObjGen og) const noexcept
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{
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if (og.getObj() >= toI(table.size())) {
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int id = og.getObj();
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if (id < 1 || static_cast<size_t>(id) >= table.size()) {
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return 0;
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}
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auto& e = table.at(toS(og.getObj()));
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return e.gen == og.getGen() ? e.entry.getOffset() : 0;
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return table[static_cast<size_t>(id)].offset();
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}
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// Returns 0 if og is not in table.
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// Returns 0 if id is not in table.
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int
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stream_number(int id) const
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stream_number(int id) const noexcept
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{
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if (id < 1 || static_cast<size_t>(id) >= table.size()) {
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return 0;
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}
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return table[static_cast<size_t>(id)].entry.getObjStreamNumber();
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return table[static_cast<size_t>(id)].stream_number();
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}
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int
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stream_index(int id) const
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stream_index(int id) const noexcept
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{
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if (id < 1 || static_cast<size_t>(id) >= table.size()) {
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return 0;
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}
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return table[static_cast<size_t>(id)].entry.getObjStreamIndex();
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return table[static_cast<size_t>(id)].stream_index();
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}
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// Temporary access to underlying map
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@ -90,9 +93,19 @@ class QPDF::Xref_table
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{
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std::map<QPDFObjGen, QPDFXRefEntry> result;
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int i{0};
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for (auto const& [gen, entry]: table) {
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if (entry.getType()) {
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result.emplace(QPDFObjGen(i, gen), entry);
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for (auto const& item: table) {
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switch (item.type()) {
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case 0:
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break;
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case 1:
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result.emplace(QPDFObjGen(i, item.gen()), item.offset());
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break;
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case 2:
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result.emplace(
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QPDFObjGen(i, 0), QPDFXRefEntry(item.stream_number(), item.stream_index()));
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break;
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default:
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throw std::logic_error("Xref_table: invalid entry type");
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}
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++i;
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}
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@ -149,10 +162,62 @@ class QPDF::Xref_table
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// Object, count, offset of first entry
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typedef std::tuple<int, int, qpdf_offset_t> Subsection;
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struct Uncompressed
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{
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Uncompressed(qpdf_offset_t offset) :
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offset(offset)
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{
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}
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qpdf_offset_t offset;
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};
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struct Compressed
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{
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Compressed(int stream_number, int stream_index) :
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stream_number(stream_number),
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stream_index(stream_index)
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{
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}
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int stream_number{0};
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int stream_index{0};
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};
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typedef std::variant<std::monostate, Uncompressed, Compressed> Xref;
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struct Entry
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{
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int gen{0};
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QPDFXRefEntry entry;
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int
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gen() const noexcept
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{
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return gen_;
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}
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size_t
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type() const noexcept
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{
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return entry.index();
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}
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qpdf_offset_t
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offset() const noexcept
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{
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return type() == 1 ? std::get<1>(entry).offset : 0;
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}
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int
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stream_number() const noexcept
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{
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return type() == 2 ? std::get<2>(entry).stream_number : 0;
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}
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int
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stream_index() const noexcept
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{
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return type() == 2 ? std::get<2>(entry).stream_index : 0;
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}
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int gen_{0};
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Xref entry;
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};
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void read(qpdf_offset_t offset);
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