Revert "Merge pull request #1297 from m-holger/qpdf_objects"

This reverts commit c648b9a018105a3c30b3e7f3c5f8a058d3ddd92c, reversing changes made to 12b67a3227df6b6df3a4f5f098e11cce173ff7d5.

Revert "Merge pull request #1297 from m-holger/qpdf_objects"
This reverts commit c648b9a018105a3c30b3e7f3c5f8a058d3ddd92c, reversing changes made to 12b67a3227df6b6df3a4f5f098e11cce173ff7d5.
m-holger
1 parent 4bf09ff1
Showing 11 changed files with 2369 additions and 2582 deletions
include/qpdf/QPDF.hh
libqpdf/CMakeLists.txt
libqpdf/QPDF.cc
libqpdf/QPDF_encryption.cc
libqpdf/QPDF_json.cc
libqpdf/QPDF_linearization.cc
libqpdf/QPDF_objects.cc
libqpdf/QPDF_optimization.cc
libqpdf/qpdf-c.cc
libqpdf/qpdf/QPDF_objects.hh
libqpdf/qpdf/QPDF_private.hh
@@ -391,7 +391,7 @@ class QPDF
     void replaceObject(int objid, int generation, QPDFObjectHandle);
     // Swap two objects given by ID. Prior to qpdf 10.2.1, existing QPDFObjectHandle instances that
-    // reference the objects did not notice the swap, but this was fixed in 10.2.1.
+    // reference them objects not notice the swap, but this was fixed in 10.2.1.
     QPDF_DLL
     void swapObjects(QPDFObjGen const& og1, QPDFObjGen const& og2);
     QPDF_DLL
@@ -645,7 +645,7 @@ class QPDF
     QPDF_DLL
     void fixDanglingReferences(bool force = false);
-    // Return the approximate number of indirect objects. It is approximate because not all objects
+    // Return the approximate number of indirect objects. It is/ approximate because not all objects
     // in the file are preserved in all cases, and gaps in object numbering are not preserved.
     QPDF_DLL
     size_t getObjectCount();
@@ -730,10 +730,10 @@ class QPDF
     class Writer;
     class Resolver;
     class StreamCopier;
-    class Objects;
     class ParseGuard;
     class Pipe;
     class JobSetter;
+    class Xref_table;
     // For testing only -- do not add to DLL
     static bool test_json_validators();
@@ -748,6 +748,7 @@ class QPDF
     static std::string const qpdf_version;
+    class ObjCache;
     class ObjCopier;
     class EncryptionParameters;
     class ForeignStreamData;
@@ -756,15 +757,36 @@ class QPDF
     class ResolveRecorder;
     class JSONReactor;
-    inline Objects& objects() noexcept;
-    inline Objects const& objects() const noexcept;
     void parse(char const* password);
     void inParse(bool);
     void setLastObjectDescription(std::string const& description, QPDFObjGen const& og);
+    QPDFObjectHandle readObject(std::string const& description, QPDFObjGen og);
+    void readStream(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset);
+    void validateStreamLineEnd(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset);
+    QPDFObjectHandle readObjectInStream(std::shared_ptr<InputSource>& input, int obj);
+    size_t recoverStreamLength(
+        std::shared_ptr<InputSource> input, QPDFObjGen const& og, qpdf_offset_t stream_offset);
     QPDFTokenizer::Token readToken(InputSource&, size_t max_len = 0);
+    QPDFObjectHandle readObjectAtOffset(
+        bool attempt_recovery,
+        qpdf_offset_t offset,
+        std::string const& description,
+        QPDFObjGen exp_og,
+        QPDFObjGen& og,
+        bool skip_cache_if_in_xref);
+    QPDFObject* resolve(QPDFObjGen og);
+    void resolveObjectsInStream(int obj_stream_number);
     void stopOnError(std::string const& message);
+    QPDFObjGen nextObjGen();
     QPDFObjectHandle newIndirect(QPDFObjGen const&, std::shared_ptr<QPDFObject> const&);
+    QPDFObjectHandle makeIndirectFromQPDFObject(std::shared_ptr<QPDFObject> const& obj);
+    bool isCached(QPDFObjGen const& og);
+    bool isUnresolved(QPDFObjGen const& og);
+    std::shared_ptr<QPDFObject> getObjectForParser(int id, int gen, bool parse_pdf);
+    std::shared_ptr<QPDFObject> getObjectForJSON(int id, int gen);
+    void removeObject(QPDFObjGen og);
+    void updateCache(QPDFObjGen const& og, std::shared_ptr<QPDFObject> const& object);
     static QPDFExc damagedPDF(
         InputSource& input,
         std::string const& object,
@@ -809,7 +831,8 @@ class QPDF
     void optimize(
         QPDFWriter::ObjTable const& obj,
         std::function<int(QPDFObjectHandle&)> skip_stream_parameters);
-    void optimize(Objects const& obj);
+    void optimize(Xref_table const& obj);
+    size_t tableSize();
     // Get lists of all objects in order according to the part of a linearized file that they belong
     // to.
@@ -829,6 +852,12 @@ class QPDF
         int& O,
         bool compressed);
+    // Get a list of objects that would be permitted in an object stream.
+    template <typename T>
+    std::vector<T> getCompressibleObjGens();
+    std::vector<QPDFObjGen> getCompressibleObjVector();
+    std::vector<bool> getCompressibleObjSet();
+
     // methods to support page handling
     void getAllPagesInternal(
@@ -902,7 +931,7 @@ class QPDF
     QPDFObjectHandle
     getUncompressedObject(QPDFObjectHandle&, std::map<int, int> const& object_stream_data);
     QPDFObjectHandle getUncompressedObject(QPDFObjectHandle&, QPDFWriter::ObjTable const& obj);
-    QPDFObjectHandle getUncompressedObject(QPDFObjectHandle&, Objects const& obj);
+    QPDFObjectHandle getUncompressedObject(QPDFObjectHandle&, Xref_table const& obj);
     int lengthNextN(int first_object, int n);
     void
     checkHPageOffset(std::vector<QPDFObjectHandle> const& pages, std::map<int, int>& idx_to_obj);
@@ -948,7 +977,7 @@ class QPDF
         std::function<int(QPDFObjectHandle&)> skip_stream_parameters);
     void filterCompressedObjects(std::map<int, int> const& object_stream_data);
     void filterCompressedObjects(QPDFWriter::ObjTable const& object_stream_data);
-    void filterCompressedObjects(Objects const& object_stream_data);
+    void filterCompressedObjects(Xref_table const& object_stream_data);
     // JSON import
     void importJSON(std::shared_ptr<InputSource>, bool must_be_complete);
@@ -107,7 +107,6 @@ set(libqpdf_SOURCES
   QPDF_encryption.cc
   QPDF_json.cc
   QPDF_linearization.cc
-  QPDF_objects.cc
   QPDF_optimization.cc
   QPDF_pages.cc
   QTC.cc
@@ -2,8 +2,10 @@
 #include <qpdf/QPDF_private.hh>
+#include <array>
 #include <atomic>
 #include <cstring>
+#include <limits>
 #include <map>
 #include <regex>
 #include <sstream>
@@ -185,7 +187,7 @@ QPDF::Members::Members(QPDF&amp; qpdf) :
     file_sp(new InvalidInputSource(no_input_name)),
     file(file_sp.get()),
     encp(new EncryptionParameters),
-    objects(qpdf, this, file)
+    xref_table(qpdf, file)
 {
 }
@@ -199,7 +201,25 @@ QPDF::QPDF() :
     m->unique_id = unique_id.fetch_add(1ULL);
 }
-QPDF::~QPDF() = default;
+QPDF::~QPDF()
+{
+    // If two objects are mutually referential (through each object having an array or dictionary
+    // that contains an indirect reference to the other), the circular references in the
+    // std::shared_ptr objects will prevent the objects from being deleted. Walk through all objects
+    // in the object cache, which is those objects that we read from the file, and break all
+    // resolved indirect references by replacing them with an internal object type representing that
+    // they have been destroyed. Note that we can't break references like this at any time when the
+    // QPDF object is active. The call to reset also causes all direct QPDFObjectHandle objects that
+    // are reachable from this object to release their association with this QPDF. Direct objects
+    // are not destroyed since they can be moved to other QPDF objects safely.
+
+    for (auto const& iter: m->obj_cache) {
+        iter.second.object->disconnect();
+        if (iter.second.object->getTypeCode() != ::ot_null) {
+            iter.second.object->destroy();
+        }
+    }
+}
 std::shared_ptr<QPDF>
 QPDF::create()
@@ -260,7 +280,7 @@ QPDF::emptyPDF()
 {
     m->pdf_version = "1.3";
     m->no_input_name = "empty PDF";
-    m->objects.xref_table().initialize_empty();
+    m->xref_table.initialize_empty();
 }
 void
@@ -273,7 +293,7 @@ QPDF::registerStreamFilter(
 void
 QPDF::setIgnoreXRefStreams(bool val)
 {
-    m->objects.xref_table().ignore_streams(val);
+    m->xref_table.ignore_streams(val);
 }
 std::shared_ptr<QPDFLogger>
@@ -311,7 +331,7 @@ void
 QPDF::setAttemptRecovery(bool val)
 {
     m->attempt_recovery = val;
-    m->objects.xref_table().attempt_recovery(val);
+    m->xref_table.attempt_recovery(val);
 }
 void
@@ -389,6 +409,17 @@ QPDF::findHeader()
     return valid;
 }
+bool
+QPDF::findStartxref()
+{
+    if (readToken(*m->file).isWord("startxref") && readToken(*m->file).isInteger()) {
+        // Position in front of offset token
+        m->file->seek(m->file->getLastOffset(), SEEK_SET);
+        return true;
+    }
+    return false;
+}
+
 void
 QPDF::parse(char const* password)
 {
@@ -405,9 +436,9 @@ QPDF::parse(char const* password)
         m->pdf_version = "1.2";
     }
-    m->objects.xref_table().initialize();
+    m->xref_table.initialize();
     initializeEncryption();
-    if (m->objects.xref_table().size() > 0 && !getRoot().getKey("/Pages").isDictionary()) {
+    if (m->xref_table.size() > 0 && !getRoot().getKey("/Pages").isDictionary()) {
         // QPDFs created from JSON have an empty xref table and no root object yet.
         throw damagedPDF("", 0, "unable to find page tree");
     }
@@ -422,35 +453,1084 @@ QPDF::inParse(bool v)
         throw std::logic_error("QPDF: re-entrant parsing detected. This is a qpdf bug."
                                " Please report at https://github.com/qpdf/qpdf/issues.");
     }
-    m->in_parse = v;
+    m->in_parse = v;
+}
+
+void
+QPDF::warn(QPDFExc const& e)
+{
+    if (m->max_warnings > 0 && m->warnings.size() >= m->max_warnings) {
+        stopOnError("Too many warnings - file is too badly damaged");
+    }
+    m->warnings.push_back(e);
+    if (!m->suppress_warnings) {
+        *m->log->getWarn() << "WARNING: " << m->warnings.back().what() << "\n";
+    }
+}
+
+void
+QPDF::warn(
+    qpdf_error_code_e error_code,
+    std::string const& object,
+    qpdf_offset_t offset,
+    std::string const& message)
+{
+    warn(QPDFExc(error_code, getFilename(), object, offset, message));
+}
+
+void
+QPDF::Xref_table::initialize_empty()
+{
+    initialized_ = true;
+    trailer_ = QPDFObjectHandle::newDictionary();
+    auto rt = qpdf.makeIndirectObject(QPDFObjectHandle::newDictionary());
+    auto pgs = qpdf.makeIndirectObject(QPDFObjectHandle::newDictionary());
+    pgs.replaceKey("/Type", QPDFObjectHandle::newName("/Pages"));
+    pgs.replaceKey("/Kids", QPDFObjectHandle::newArray());
+    pgs.replaceKey("/Count", QPDFObjectHandle::newInteger(0));
+    rt.replaceKey("/Type", QPDFObjectHandle::newName("/Catalog"));
+    rt.replaceKey("/Pages", pgs);
+    trailer_.replaceKey("/Root", rt);
+    trailer_.replaceKey("/Size", QPDFObjectHandle::newInteger(3));
+}
+
+void
+QPDF::Xref_table::initialize_json()
+{
+    initialized_ = true;
+    table.resize(1);
+    trailer_ = QPDFObjectHandle::newDictionary();
+    trailer_.replaceKey("/Size", QPDFObjectHandle::newInteger(1));
+}
+
+void
+QPDF::Xref_table::initialize()
+{
+    // PDF spec says %%EOF must be found within the last 1024 bytes of/ the file.  We add an extra
+    // 30 characters to leave room for the startxref stuff.
+    file->seek(0, SEEK_END);
+    qpdf_offset_t end_offset = file->tell();
+    // Sanity check on object ids. All objects must appear in xref table / stream. In all realistic
+    // scenarios at least 3 bytes are required.
+    if (max_id_ > end_offset / 3) {
+        max_id_ = static_cast<int>(end_offset / 3);
+    }
+    qpdf_offset_t start_offset = (end_offset > 1054 ? end_offset - 1054 : 0);
+    PatternFinder sf(qpdf, &QPDF::findStartxref);
+    qpdf_offset_t xref_offset = 0;
+    if (file->findLast("startxref", start_offset, 0, sf)) {
+        xref_offset = QUtil::string_to_ll(read_token().getValue().c_str());
+    }
+
+    try {
+        if (xref_offset == 0) {
+            QTC::TC("qpdf", "QPDF can't find startxref");
+            throw damaged_pdf("can't find startxref");
+        }
+        try {
+            read(xref_offset);
+        } catch (QPDFExc&) {
+            throw;
+        } catch (std::exception& e) {
+            throw damaged_pdf(std::string("error reading xref: ") + e.what());
+        }
+    } catch (QPDFExc& e) {
+        if (attempt_recovery_) {
+            reconstruct(e);
+            QTC::TC("qpdf", "QPDF reconstructed xref table");
+        } else {
+            throw;
+        }
+    }
+
+    initialized_ = true;
+}
+
+void
+QPDF::Xref_table::reconstruct(QPDFExc& e)
+{
+    if (reconstructed_) {
+        // Avoid xref reconstruction infinite loops. This is getting very hard to reproduce because
+        // qpdf is throwing many fewer exceptions while parsing. Most situations are warnings now.
+        throw e;
+    }
+
+    // If recovery generates more than 1000 warnings, the file is so severely damaged that there
+    // probably is no point trying to continue.
+    const auto max_warnings = qpdf.m->warnings.size() + 1000U;
+    auto check_warnings = [this, max_warnings]() {
+        if (qpdf.m->warnings.size() > max_warnings) {
+            throw damaged_pdf("too many errors while reconstructing cross-reference table");
+        }
+    };
+
+    reconstructed_ = true;
+    // We may find more objects, which may contain dangling references.
+    qpdf.m->fixed_dangling_refs = false;
+
+    warn_damaged("file is damaged");
+    qpdf.warn(e);
+    warn_damaged("Attempting to reconstruct cross-reference table");
+
+    // Delete all references to type 1 (uncompressed) objects
+    for (auto& iter: table) {
+        if (iter.type() == 1) {
+            iter = {};
+        }
+    }
+
+    std::vector<std::tuple<int, int, qpdf_offset_t>> objects;
+    std::vector<qpdf_offset_t> trailers;
+    int max_found = 0;
+
+    file->seek(0, SEEK_END);
+    qpdf_offset_t eof = file->tell();
+    file->seek(0, SEEK_SET);
+    // Don't allow very long tokens here during recovery. All the interesting tokens are covered.
+    static size_t const MAX_LEN = 10;
+    while (file->tell() < eof) {
+        QPDFTokenizer::Token t1 = read_token(MAX_LEN);
+        qpdf_offset_t token_start = file->tell() - toO(t1.getValue().length());
+        if (t1.isInteger()) {
+            auto pos = file->tell();
+            QPDFTokenizer::Token t2 = read_token(MAX_LEN);
+            if (t2.isInteger() && read_token(MAX_LEN).isWord("obj")) {
+                int obj = QUtil::string_to_int(t1.getValue().c_str());
+                int gen = QUtil::string_to_int(t2.getValue().c_str());
+                if (obj <= max_id_) {
+                    objects.emplace_back(obj, gen, token_start);
+                    if (obj > max_found) {
+                        max_found = obj;
+                    }
+                } else {
+                    warn_damaged("ignoring object with impossibly large id " + std::to_string(obj));
+                }
+            }
+            file->seek(pos, SEEK_SET);
+        } else if (!trailer_ && t1.isWord("trailer")) {
+            trailers.emplace_back(file->tell());
+        }
+        file->findAndSkipNextEOL();
+    }
+
+    table.resize(toS(max_found) + 1);
+
+    for (auto tr: trailers) {
+        file->seek(tr, SEEK_SET);
+        auto t = read_trailer();
+        if (!t.isDictionary()) {
+            // Oh well.  It was worth a try.
+        } else {
+            trailer_ = t;
+            break;
+        }
+        check_warnings();
+    }
+
+    auto rend = objects.rend();
+    for (auto it = objects.rbegin(); it != rend; it++) {
+        auto [obj, gen, token_start] = *it;
+        insert(obj, 1, token_start, gen);
+        check_warnings();
+    }
+
+    if (!trailer_) {
+        qpdf_offset_t max_offset{0};
+        // If there are any xref streams, take the last one to appear.
+        int i = -1;
+        for (auto const& item: table) {
+            ++i;
+            if (item.type() != 1) {
+                continue;
+            }
+            auto oh = qpdf.getObject(i, item.gen());
+            try {
+                if (!oh.isStreamOfType("/XRef")) {
+                    continue;
+                }
+            } catch (std::exception&) {
+                continue;
+            }
+            auto offset = item.offset();
+            if (offset > max_offset) {
+                max_offset = offset;
+                trailer_ = oh.getDict();
+            }
+            check_warnings();
+        }
+        if (max_offset > 0) {
+            try {
+                read(max_offset);
+            } catch (std::exception&) {
+                throw damaged_pdf(
+                    "error decoding candidate xref stream while recovering damaged file");
+            }
+            QTC::TC("qpdf", "QPDF recover xref stream");
+        }
+    }
+
+    if (!trailer_) {
+        // We could check the last encountered object to see if it was an xref stream.  If so, we
+        // could try to get the trailer from there.  This may make it possible to recover files with
+        // bad startxref pointers even when they have object streams.
+
+        throw damaged_pdf("unable to find trailer dictionary while recovering damaged file");
+    }
+    if (table.empty()) {
+        // We cannot check for an empty xref table in parse because empty tables are valid when
+        // creating QPDF objects from JSON.
+        throw damaged_pdf("unable to find objects while recovering damaged file");
+    }
+    check_warnings();
+    if (!initialized_) {
+        initialized_ = true;
+        qpdf.getAllPages();
+        check_warnings();
+        if (qpdf.m->all_pages.empty()) {
+            initialized_ = false;
+            throw damaged_pdf("unable to find any pages while recovering damaged file");
+        }
+    }
+    // We could iterate through the objects looking for streams and try to find objects inside of
+    // them, but it's probably not worth the trouble.  Acrobat can't recover files with any errors
+    // in an xref stream, and this would be a real long shot anyway.  If we wanted to do anything
+    // that involved looking at stream contents, we'd also have to call initializeEncryption() here.
+    // It's safe to call it more than once.
+}
+
+void
+QPDF::Xref_table::read(qpdf_offset_t xref_offset)
+{
+    std::map<int, int> free_table;
+    std::set<qpdf_offset_t> visited;
+    while (xref_offset) {
+        visited.insert(xref_offset);
+        char buf[7];
+        memset(buf, 0, sizeof(buf));
+        file->seek(xref_offset, SEEK_SET);
+        // Some files miss the mark a little with startxref. We could do a better job of searching
+        // in the neighborhood for something that looks like either an xref table or stream, but the
+        // simple heuristic of skipping whitespace can help with the xref table case and is harmless
+        // with the stream case.
+        bool done = false;
+        bool skipped_space = false;
+        while (!done) {
+            char ch;
+            if (1 == file->read(&ch, 1)) {
+                if (QUtil::is_space(ch)) {
+                    skipped_space = true;
+                } else {
+                    file->unreadCh(ch);
+                    done = true;
+                }
+            } else {
+                QTC::TC("qpdf", "QPDF eof skipping spaces before xref", skipped_space ? 0 : 1);
+                done = true;
+            }
+        }
+
+        file->read(buf, sizeof(buf) - 1);
+        // The PDF spec says xref must be followed by a line terminator, but files exist in the wild
+        // where it is terminated by arbitrary whitespace.
+        if ((strncmp(buf, "xref", 4) == 0) && QUtil::is_space(buf[4])) {
+            if (skipped_space) {
+                QTC::TC("qpdf", "QPDF xref skipped space");
+                warn_damaged("extraneous whitespace seen before xref");
+            }
+            QTC::TC(
+                "qpdf",
+                "QPDF xref space",
+                ((buf[4] == '\n')       ? 0
+                     : (buf[4] == '\r') ? 1
+                     : (buf[4] == ' ')  ? 2
+                                        : 9999));
+            int skip = 4;
+            // buf is null-terminated, and QUtil::is_space('\0') is false, so this won't overrun.
+            while (QUtil::is_space(buf[skip])) {
+                ++skip;
+            }
+            xref_offset = process_section(xref_offset + skip);
+        } else {
+            xref_offset = read_stream(xref_offset);
+        }
+        if (visited.count(xref_offset) != 0) {
+            QTC::TC("qpdf", "QPDF xref loop");
+            throw damaged_pdf("loop detected following xref tables");
+        }
+    }
+
+    if (!trailer_) {
+        throw damaged_pdf("unable to find trailer while reading xref");
+    }
+    int size = trailer_.getKey("/Size").getIntValueAsInt();
+
+    if (size < 3) {
+        throw damaged_pdf("too few objects - file can't have a page tree");
+    }
+
+    // We are no longer reporting what the highest id in the xref table is. I don't think it adds
+    // anything. If we want to report more detail, we should report the total number of missing
+    // entries, including missing entries before the last actual entry.
+}
+
+QPDF::Xref_table::Subsection
+QPDF::Xref_table::subsection(std::string const& line)
+{
+    auto terminate = [this]() -> void {
+        QTC::TC("qpdf", "QPDF invalid xref");
+        throw damaged_table("xref syntax invalid");
+    };
+
+    // is_space and is_digit both return false on '\0', so this will not overrun the null-terminated
+    // buffer.
+    char const* p = line.c_str();
+    char const* start = line.c_str();
+
+    // Skip zero or more spaces
+    while (QUtil::is_space(*p)) {
+        ++p;
+    }
+    // Require digit
+    if (!QUtil::is_digit(*p)) {
+        terminate();
+    }
+    // Gather digits
+    std::string obj_str;
+    while (QUtil::is_digit(*p)) {
+        obj_str.append(1, *p++);
+    }
+    // Require space
+    if (!QUtil::is_space(*p)) {
+        terminate();
+    }
+    // Skip spaces
+    while (QUtil::is_space(*p)) {
+        ++p;
+    }
+    // Require digit
+    if (!QUtil::is_digit(*p)) {
+        terminate();
+    }
+    // Gather digits
+    std::string num_str;
+    while (QUtil::is_digit(*p)) {
+        num_str.append(1, *p++);
+    }
+    // Skip any space including line terminators
+    while (QUtil::is_space(*p)) {
+        ++p;
+    }
+    auto obj = QUtil::string_to_int(obj_str.c_str());
+    auto count = QUtil::string_to_int(num_str.c_str());
+    if (obj > max_id() || count > max_id() || (obj + count) > max_id()) {
+        throw damaged_table("xref table subsection header contains impossibly large entry");
+    }
+    return {obj, count, file->getLastOffset() + toI(p - start)};
+}
+
+std::vector<QPDF::Xref_table::Subsection>
+QPDF::Xref_table::bad_subsections(std::string& line, qpdf_offset_t start)
+{
+    std::vector<QPDF::Xref_table::Subsection> result;
+    file->seek(start, SEEK_SET);
+
+    while (true) {
+        line.assign(50, '\0');
+        file->read(line.data(), line.size());
+        auto [obj, num, offset] = result.emplace_back(subsection(line));
+        file->seek(offset, SEEK_SET);
+        for (qpdf_offset_t i = obj; i - num < obj; ++i) {
+            if (!std::get<0>(read_entry())) {
+                QTC::TC("qpdf", "QPDF invalid xref entry");
+                throw damaged_table("invalid xref entry (obj=" + std::to_string(i) + ")");
+            }
+        }
+        qpdf_offset_t pos = file->tell();
+        if (read_token().isWord("trailer")) {
+            return result;
+        } else {
+            file->seek(pos, SEEK_SET);
+        }
+    }
+}
+
+// Optimistically read and parse all subsection headers. If an error is encountered return the
+// result of bad_subsections.
+std::vector<QPDF::Xref_table::Subsection>
+QPDF::Xref_table::subsections(std::string& line)
+{
+    auto recovery_offset = file->tell();
+    try {
+        std::vector<QPDF::Xref_table::Subsection> result;
+
+        while (true) {
+            line.assign(50, '\0');
+            file->read(line.data(), line.size());
+            auto& sub = result.emplace_back(subsection(line));
+            auto count = std::get<1>(sub);
+            auto offset = std::get<2>(sub);
+            file->seek(offset + 20 * toO(count) - 1, SEEK_SET);
+            file->read(line.data(), 1);
+            if (!(line[0] == '\n' || line[0] == '\n')) {
+                return bad_subsections(line, recovery_offset);
+            }
+            qpdf_offset_t pos = file->tell();
+            if (read_token().isWord("trailer")) {
+                return result;
+            } else {
+                file->seek(pos, SEEK_SET);
+            }
+        }
+    } catch (...) {
+        return bad_subsections(line, recovery_offset);
+    }
+}
+
+// Returns (success, f1, f2, type).
+std::tuple<bool, qpdf_offset_t, int, char>
+QPDF::Xref_table::read_bad_entry()
+{
+    qpdf_offset_t f1{0};
+    int f2{0};
+    char type{'\0'};
+    // Reposition after initial read attempt and reread.
+    file->seek(file->getLastOffset(), SEEK_SET);
+    auto line = file->readLine(30);
+
+    // is_space and is_digit both return false on '\0', so this will not overrun the null-terminated
+    // buffer.
+    char const* p = line.data();
+
+    // Skip zero or more spaces. There aren't supposed to be any.
+    bool invalid = false;
+    while (QUtil::is_space(*p)) {
+        ++p;
+        QTC::TC("qpdf", "QPDF ignore first space in xref entry");
+        invalid = true;
+    }
+    // Require digit
+    if (!QUtil::is_digit(*p)) {
+        return {false, 0, 0, '\0'};
+    }
+    // Gather digits
+    std::string f1_str;
+    while (QUtil::is_digit(*p)) {
+        f1_str.append(1, *p++);
+    }
+    // Require space
+    if (!QUtil::is_space(*p)) {
+        return {false, 0, 0, '\0'};
+    }
+    if (QUtil::is_space(*(p + 1))) {
+        QTC::TC("qpdf", "QPDF ignore first extra space in xref entry");
+        invalid = true;
+    }
+    // Skip spaces
+    while (QUtil::is_space(*p)) {
+        ++p;
+    }
+    // Require digit
+    if (!QUtil::is_digit(*p)) {
+        return {false, 0, 0, '\0'};
+    }
+    // Gather digits
+    std::string f2_str;
+    while (QUtil::is_digit(*p)) {
+        f2_str.append(1, *p++);
+    }
+    // Require space
+    if (!QUtil::is_space(*p)) {
+        return {false, 0, 0, '\0'};
+    }
+    if (QUtil::is_space(*(p + 1))) {
+        QTC::TC("qpdf", "QPDF ignore second extra space in xref entry");
+        invalid = true;
+    }
+    // Skip spaces
+    while (QUtil::is_space(*p)) {
+        ++p;
+    }
+    if ((*p == 'f') || (*p == 'n')) {
+        type = *p;
+    } else {
+        return {false, 0, 0, '\0'};
+    }
+    if ((f1_str.length() != 10) || (f2_str.length() != 5)) {
+        QTC::TC("qpdf", "QPDF ignore length error xref entry");
+        invalid = true;
+    }
+
+    if (invalid) {
+        qpdf.warn(damaged_table("accepting invalid xref table entry"));
+    }
+
+    f1 = QUtil::string_to_ll(f1_str.c_str());
+    f2 = QUtil::string_to_int(f2_str.c_str());
+
+    return {true, f1, f2, type};
+}
+
+// Optimistically read and parse xref entry. If entry is bad, call read_bad_xrefEntry and return
+// result. Returns (success, f1, f2, type).
+std::tuple<bool, qpdf_offset_t, int, char>
+QPDF::Xref_table::read_entry()
+{
+    qpdf_offset_t f1{0};
+    int f2{0};
+    char type{'\0'};
+    std::array<char, 21> line;
+    f1 = 0;
+    f2 = 0;
+    if (file->read(line.data(), 20) != 20) {
+        // C++20: [[unlikely]]
+        return {false, 0, 0, '\0'};
+    }
+    line[20] = '\0';
+    char const* p = line.data();
+
+    int f1_len = 0;
+    int f2_len = 0;
+
+    // is_space and is_digit both return false on '\0', so this will not overrun the null-terminated
+    // buffer.
+
+    // Gather f1 digits. NB No risk of overflow as 9'999'999'999 < max long long.
+    while (*p == '0') {
+        ++f1_len;
+        ++p;
+    }
+    while (QUtil::is_digit(*p) && f1_len++ < 10) {
+        f1 *= 10;
+        f1 += *p++ - '0';
+    }
+    // Require space
+    if (!QUtil::is_space(*p++)) {
+        // Entry doesn't start with space or digit.
+        // C++20: [[unlikely]]
+        return {false, 0, 0, '\0'};
+    }
+    // Gather digits. NB No risk of overflow as 99'999 < max int.
+    while (*p == '0') {
+        ++f2_len;
+        ++p;
+    }
+    while (QUtil::is_digit(*p) && f2_len++ < 5) {
+        f2 *= 10;
+        f2 += static_cast<int>(*p++ - '0');
+    }
+    if (QUtil::is_space(*p++) && (*p == 'f' || *p == 'n')) {
+        // C++20: [[likely]]
+        type = *p;
+        // No test for valid line[19].
+        if (*(++p) && *(++p) && (*p == '\n' || *p == '\r') && f1_len == 10 && f2_len == 5) {
+            // C++20: [[likely]]
+            return {true, f1, f2, type};
+        }
+    }
+    return read_bad_entry();
+}
+
+// Read a single cross-reference table section and associated trailer.
+qpdf_offset_t
+QPDF::Xref_table::process_section(qpdf_offset_t xref_offset)
+{
+    file->seek(xref_offset, SEEK_SET);
+    std::string line;
+    auto subs = subsections(line);
+
+    auto cur_trailer_offset = file->tell();
+    auto cur_trailer = read_trailer();
+    if (!cur_trailer.isDictionary()) {
+        QTC::TC("qpdf", "QPDF missing trailer");
+        throw qpdf.damagedPDF("", "expected trailer dictionary");
+    }
+
+    if (!trailer_) {
+        unsigned int sz;
+        trailer_ = cur_trailer;
+
+        if (!trailer_.hasKey("/Size")) {
+            QTC::TC("qpdf", "QPDF trailer lacks size");
+            throw qpdf.damagedPDF("trailer", "trailer dictionary lacks /Size key");
+        }
+        if (!trailer_.getKey("/Size").getValueAsUInt(sz)) {
+            QTC::TC("qpdf", "QPDF trailer size not integer");
+            throw qpdf.damagedPDF("trailer", "/Size key in trailer dictionary is not an integer");
+        }
+        if (sz >= static_cast<unsigned int>(max_id_)) {
+            QTC::TC("qpdf", "QPDF trailer size impossibly large");
+            throw qpdf.damagedPDF("trailer", "/Size key in trailer dictionary is impossibly large");
+        }
+        table.resize(sz);
+    }
+
+    for (auto [obj, num, offset]: subs) {
+        file->seek(offset, SEEK_SET);
+        for (qpdf_offset_t i = obj; i - num < obj; ++i) {
+            if (i == 0) {
+                // This is needed by checkLinearization()
+                first_item_offset_ = file->tell();
+            }
+            // For xref_table, these will always be small enough to be ints
+            auto [success, f1, f2, type] = read_entry();
+            if (!success) {
+                throw damaged_table("invalid xref entry (obj=" + std::to_string(i) + ")");
+            }
+            if (type == 'f') {
+                insert_free(QPDFObjGen(toI(i), f2));
+            } else {
+                insert(toI(i), 1, f1, f2);
+            }
+        }
+        qpdf_offset_t pos = file->tell();
+        if (read_token().isWord("trailer")) {
+            break;
+        } else {
+            file->seek(pos, SEEK_SET);
+        }
+    }
+
+    if (cur_trailer.hasKey("/XRefStm")) {
+        if (ignore_streams_) {
+            QTC::TC("qpdf", "QPDF ignoring XRefStm in trailer");
+        } else {
+            if (cur_trailer.getKey("/XRefStm").isInteger()) {
+                // Read the xref stream but disregard any return value -- we'll use our trailer's
+                // /Prev key instead of the xref stream's.
+                (void)read_stream(cur_trailer.getKey("/XRefStm").getIntValue());
+            } else {
+                throw qpdf.damagedPDF("xref stream", cur_trailer_offset, "invalid /XRefStm");
+            }
+        }
+    }
+
+    if (cur_trailer.hasKey("/Prev")) {
+        if (!cur_trailer.getKey("/Prev").isInteger()) {
+            QTC::TC("qpdf", "QPDF trailer prev not integer");
+            throw qpdf.damagedPDF(
+                "trailer", cur_trailer_offset, "/Prev key in trailer dictionary is not an integer");
+        }
+        QTC::TC("qpdf", "QPDF prev key in trailer dictionary");
+        return cur_trailer.getKey("/Prev").getIntValue();
+    }
+
+    return 0;
+}
+
+// Read a single cross-reference stream.
+qpdf_offset_t
+QPDF::Xref_table::read_stream(qpdf_offset_t xref_offset)
+{
+    if (!ignore_streams_) {
+        QPDFObjGen x_og;
+        QPDFObjectHandle xref_obj;
+        try {
+            xref_obj = qpdf.readObjectAtOffset(
+                false, xref_offset, "xref stream", QPDFObjGen(0, 0), x_og, true);
+        } catch (QPDFExc&) {
+            // ignore -- report error below
+        }
+        if (xref_obj.isStreamOfType("/XRef")) {
+            QTC::TC("qpdf", "QPDF found xref stream");
+            return process_stream(xref_offset, xref_obj);
+        }
+    }
+
+    QTC::TC("qpdf", "QPDF can't find xref");
+    throw qpdf.damagedPDF("", xref_offset, "xref not found");
+    return 0; // unreachable
+}
+
+// Return the entry size of the xref stream and the processed W array.
+std::pair<int, std::array<int, 3>>
+QPDF::Xref_table::process_W(
+    QPDFObjectHandle& dict, std::function<QPDFExc(std::string_view)> damaged)
+{
+    auto W_obj = dict.getKey("/W");
+    if (!(W_obj.isArray() && W_obj.getArrayNItems() >= 3 && W_obj.getArrayItem(0).isInteger() &&
+          W_obj.getArrayItem(1).isInteger() && W_obj.getArrayItem(2).isInteger())) {
+        throw damaged("Cross-reference stream does not have a proper /W key");
+    }
+
+    std::array<int, 3> W;
+    int entry_size = 0;
+    auto w_vector = W_obj.getArrayAsVector();
+    int max_bytes = sizeof(qpdf_offset_t);
+    for (size_t i = 0; i < 3; ++i) {
+        W[i] = w_vector[i].getIntValueAsInt();
+        if (W[i] > max_bytes) {
+            throw damaged("Cross-reference stream's /W contains impossibly large values");
+        }
+        if (W[i] < 0) {
+            throw damaged("Cross-reference stream's /W contains negative values");
+        }
+        entry_size += W[i];
+    }
+    if (entry_size == 0) {
+        throw damaged("Cross-reference stream's /W indicates entry size of 0");
+    }
+    return {entry_size, W};
+}
+
+// Validate Size entry and return the maximum number of entries that the xref stream can contain and
+// the value of the Size entry.
+std::pair<int, size_t>
+QPDF::Xref_table::process_Size(
+    QPDFObjectHandle& dict, int entry_size, std::function<QPDFExc(std::string_view)> damaged)
+{
+    // Number of entries is limited by the highest possible object id and stream size.
+    auto max_num_entries = std::numeric_limits<int>::max();
+    if (max_num_entries > (std::numeric_limits<qpdf_offset_t>::max() / entry_size)) {
+        max_num_entries = toI(std::numeric_limits<qpdf_offset_t>::max() / entry_size);
+    }
+
+    auto Size_obj = dict.getKey("/Size");
+    long long size;
+    if (!dict.getKey("/Size").getValueAsInt(size)) {
+        throw damaged("Cross-reference stream does not have a proper /Size key");
+    } else if (size < 0) {
+        throw damaged("Cross-reference stream has a negative /Size key");
+    } else if (size >= max_num_entries) {
+        throw damaged("Cross-reference stream has an impossibly large /Size key");
+    }
+    // We are not validating that Size <= (Size key of parent xref / trailer).
+    return {max_num_entries, toS(size)};
+}
+
+// Return the number of entries of the xref stream and the processed Index array.
+std::pair<int, std::vector<std::pair<int, int>>>
+QPDF::Xref_table::process_Index(
+    QPDFObjectHandle& dict, int max_num_entries, std::function<QPDFExc(std::string_view)> damaged)
+{
+    auto size = dict.getKey("/Size").getIntValueAsInt();
+    auto Index_obj = dict.getKey("/Index");
+
+    if (Index_obj.isArray()) {
+        std::vector<std::pair<int, int>> indx;
+        int num_entries = 0;
+        auto index_vec = Index_obj.getArrayAsVector();
+        if ((index_vec.size() % 2) || index_vec.size() < 2) {
+            throw damaged("Cross-reference stream's /Index has an invalid number of values");
+        }
+
+        int i = 0;
+        long long first = 0;
+        for (auto& val: index_vec) {
+            if (val.isInteger()) {
+                if (i % 2) {
+                    auto count = val.getIntValue();
+                    if (count <= 0) {
+                        throw damaged(
+                            "Cross-reference stream section claims to contain " +
+                            std::to_string(count) + " entries");
+                    }
+                    // We are guarding against the possibility of num_entries * entry_size
+                    // overflowing. We are not checking that entries are in ascending order as
+                    // required by the spec, which probably should generate a warning. We are also
+                    // not checking that for each subsection first object number + number of entries
+                    // <= /Size. The spec requires us to ignore object number > /Size.
+                    if (first > (max_num_entries - count) ||
+                        count > (max_num_entries - num_entries)) {
+                        throw damaged(
+                            "Cross-reference stream claims to contain too many entries: " +
+                            std::to_string(first) + " " + std::to_string(max_num_entries) + " " +
+                            std::to_string(num_entries));
+                    }
+                    indx.emplace_back(static_cast<int>(first), static_cast<int>(count));
+                    num_entries += static_cast<int>(count);
+                } else {
+                    first = val.getIntValue();
+                    if (first < 0) {
+                        throw damaged(
+                            "Cross-reference stream's /Index contains a negative object id");
+                    } else if (first > max_num_entries) {
+                        throw damaged("Cross-reference stream's /Index contains an impossibly "
+                                      "large object id");
+                    }
+                }
+            } else {
+                throw damaged(
+                    "Cross-reference stream's /Index's item " + std::to_string(i) +
+                    " is not an integer");
+            }
+            i++;
+        }
+        QTC::TC("qpdf", "QPDF xref /Index is array", index_vec.size() == 2 ? 0 : 1);
+        return {num_entries, indx};
+    } else if (Index_obj.isNull()) {
+        QTC::TC("qpdf", "QPDF xref /Index is null");
+        return {size, {{0, size}}};
+    } else {
+        throw damaged("Cross-reference stream does not have a proper /Index key");
+    }
+}
+
+qpdf_offset_t
+QPDF::Xref_table::process_stream(qpdf_offset_t xref_offset, QPDFObjectHandle& xref_obj)
+{
+    auto damaged = [this, xref_offset](std::string_view msg) -> QPDFExc {
+        return qpdf.damagedPDF("xref stream", xref_offset, msg.data());
+    };
+
+    auto dict = xref_obj.getDict();
+
+    auto [entry_size, W] = process_W(dict, damaged);
+    auto [max_num_entries, size] = process_Size(dict, entry_size, damaged);
+    auto [num_entries, indx] = process_Index(dict, max_num_entries, damaged);
+
+    std::shared_ptr<Buffer> bp = xref_obj.getStreamData(qpdf_dl_specialized);
+    size_t actual_size = bp->getSize();
+    auto expected_size = toS(entry_size) * toS(num_entries);
+
+    if (expected_size != actual_size) {
+        QPDFExc x = damaged(
+            "Cross-reference stream data has the wrong size; expected = " +
+            std::to_string(expected_size) + "; actual = " + std::to_string(actual_size));
+        if (expected_size > actual_size) {
+            throw x;
+        } else {
+            qpdf.warn(x);
+        }
+    }
+
+    if (!trailer_) {
+        trailer_ = dict;
+        if (size > toS(max_id_)) {
+            throw damaged("Cross-reference stream /Size entry is impossibly large");
+        }
+        table.resize(size);
+    }
+
+    bool saw_first_compressed_object = false;
+
+    // Actual size vs. expected size check above ensures that we will not overflow any buffers here.
+    // We know that entry_size * num_entries is less or equal to the size of the buffer.
+    auto p = bp->getBuffer();
+    for (auto [obj, sec_entries]: indx) {
+        // Process a subsection.
+        for (int i = 0; i < sec_entries; ++i) {
+            // Read this entry
+            std::array<qpdf_offset_t, 3> fields{};
+            if (W[0] == 0) {
+                QTC::TC("qpdf", "QPDF default for xref stream field 0");
+                fields[0] = 1;
+            }
+            for (size_t j = 0; j < 3; ++j) {
+                for (int k = 0; k < W[j]; ++k) {
+                    fields[j] <<= 8;
+                    fields[j] |= *p++;
+                }
+            }
+
+            // Get the generation number.  The generation number is 0 unless this is an uncompressed
+            // object record, in which case the generation number appears as the third field.
+            if (saw_first_compressed_object) {
+                if (fields[0] != 2) {
+                    uncompressed_after_compressed_ = true;
+                }
+            } else if (fields[0] == 2) {
+                saw_first_compressed_object = true;
+            }
+            if (obj == 0) {
+                // This is needed by checkLinearization()
+                first_item_offset_ = xref_offset;
+            } else if (fields[0] == 0) {
+                // Ignore fields[2], which we don't care about in this case. This works around the
+                // issue of some PDF files that put invalid values, like -1, here for deleted
+                // objects.
+                insert_free(QPDFObjGen(obj, 0));
+            } else {
+                insert(obj, toI(fields[0]), fields[1], toI(fields[2]));
+            }
+            ++obj;
+        }
+    }
+
+    if (dict.hasKey("/Prev")) {
+        if (!dict.getKey("/Prev").isInteger()) {
+            throw qpdf.damagedPDF(
+                "xref stream", "/Prev key in xref stream dictionary is not an integer");
+        }
+        QTC::TC("qpdf", "QPDF prev key in xref stream dictionary");
+        return dict.getKey("/Prev").getIntValue();
+    } else {
+        return 0;
+    }
+}
+
+void
+QPDF::Xref_table::insert(int obj, int f0, qpdf_offset_t f1, int f2)
+{
+    // Populate the xref table in such a way that the first reference to an object that we see,
+    // which is the one in the latest xref table in which it appears, is the one that gets stored.
+    // This works because we are reading more recent appends before older ones.
+
+    // If there is already an entry for this object and generation in the table, it means that a
+    // later xref table has registered this object.  Disregard this one.
+
+    int new_gen = f0 == 2 ? 0 : f2;
+
+    if (!(obj > 0 && static_cast<size_t>(obj) < table.size() && 0 <= f2 && new_gen < 65535)) {
+        // We are ignoring invalid objgens. Most will arrive here from xref reconstruction. There
+        // is probably no point having another warning but we could count invalid items in order to
+        // decide when to give up.
+        QTC::TC("qpdf", "QPDF xref overwrite invalid objgen");
+        return;
+    }
+
+    auto& entry = table[static_cast<size_t>(obj)];
+    auto old_type = entry.type();
+
+    if (!old_type && entry.gen() > 0) {
+        // At the moment we are processing the updates last to first and therefore the gen doesn't
+        // matter as long as it > 0 to distinguish it from an uninitialized entry. This will need
+        // to be revisited when we want to support incremental updates or more comprhensive
+        // checking.
+        QTC::TC("qpdf", "QPDF xref deleted object");
+        return;
+    }
+
+    if (f0 == 2 && static_cast<int>(f1) == obj) {
+        qpdf.warn(qpdf.damagedPDF(
+            "xref stream", "self-referential object stream " + std::to_string(obj)));
+        return;
+    }
+
+    if (old_type && entry.gen() >= new_gen) {
+        QTC::TC("qpdf", "QPDF xref reused object");
+        return;
+    }
+
+    switch (f0) {
+    case 1:
+        // f2 is generation
+        QTC::TC("qpdf", "QPDF xref gen > 0", (f2 > 0) ? 1 : 0);
+        entry = {f2, Uncompressed(f1)};
+        break;
+
+    case 2:
+        entry = {0, Compressed(toI(f1), f2)};
+        object_streams_ = true;
+        break;
+
+    default:
+        throw qpdf.damagedPDF(
+            "xref stream", "unknown xref stream entry type " + std::to_string(f0));
+        break;
+    }
 }
 void
-QPDF::warn(QPDFExc const& e)
+QPDF::Xref_table::insert_free(QPDFObjGen og)
 {
-    if (m->max_warnings > 0 && m->warnings.size() >= m->max_warnings) {
-        stopOnError("Too many warnings - file is too badly damaged");
+    // At the moment we are processing the updates last to first and therefore the gen doesn't
+    // matter as long as it > 0 to distinguish it from an uninitialized entry. This will need to be
+    // revisited when we want to support incremental updates or more comprhensive checking.
+    if (og.getObj() < 1) {
+        return;
     }
-    m->warnings.push_back(e);
-    if (!m->suppress_warnings) {
-        *m->log->getWarn() << "WARNING: " << m->warnings.back().what() << "\n";
+    size_t id = static_cast<size_t>(og.getObj());
+    if (id < table.size() && !type(id)) {
+        table[id] = {1, {}};
     }
 }
-void
-QPDF::warn(
-    qpdf_error_code_e error_code,
-    std::string const& object,
-    qpdf_offset_t offset,
-    std::string const& message)
+QPDFObjGen
+QPDF::Xref_table::at_offset(qpdf_offset_t offset) const noexcept
 {
-    warn(QPDFExc(error_code, getFilename(), object, offset, message));
+    int id = 0;
+    int gen = 0;
+    qpdf_offset_t start = 0;
+
+    int i = 0;
+    for (auto const& item: table) {
+        auto o = item.offset();
+        if (start < o && o <= offset) {
+            start = o;
+            id = i;
+            gen = item.gen();
+        }
+        ++i;
+    }
+    return QPDFObjGen(id, gen);
+}
+
+std::map<QPDFObjGen, QPDFXRefEntry>
+QPDF::Xref_table::as_map() const
+{
+    std::map<QPDFObjGen, QPDFXRefEntry> result;
+    int i{0};
+    for (auto const& item: table) {
+        switch (item.type()) {
+        case 0:
+            break;
+        case 1:
+            result.emplace(QPDFObjGen(i, item.gen()), item.offset());
+            break;
+        case 2:
+            result.emplace(
+                QPDFObjGen(i, 0), QPDFXRefEntry(item.stream_number(), item.stream_index()));
+            break;
+        default:
+            throw std::logic_error("Xref_table: invalid entry type");
+        }
+        ++i;
+    }
+    return result;
 }
 void
 QPDF::showXRefTable()
 {
-    m->objects.xref_table().show();
+    m->xref_table.show();
+}
+
+void
+QPDF::Xref_table::show()
+{
+    auto& cout = *qpdf.m->log->getInfo();
+    int i = -1;
+    for (auto const& item: table) {
+        ++i;
+        if (item.type()) {
+            cout << std::to_string(i) << "/" << std::to_string(item.gen()) << ": ";
+            switch (item.type()) {
+            case 1:
+                cout << "uncompressed; offset = " << item.offset() << "\n";
+                break;
+
+            case 2:
+                cout << "compressed; stream = " << item.stream_number()
+                     << ", index = " << item.stream_index() << "\n";
+                break;
+
+            default:
+                throw std::logic_error(
+                    "unknown cross-reference table type while showing xref_table");
+            }
+        }
+    }
+}
+
+// Resolve all objects in the xref table. If this triggers a xref table reconstruction abort and
+// return false. Otherwise return true.
+bool
+QPDF::Xref_table::resolve()
+{
+    bool may_change = !reconstructed_;
+    int i = -1;
+    for (auto& item: table) {
+        ++i;
+        if (item.type()) {
+            if (qpdf.isUnresolved(QPDFObjGen(i, item.gen()))) {
+                qpdf.resolve(QPDFObjGen(i, item.gen()));
+                if (may_change && reconstructed_) {
+                    return false;
+                }
+            }
+        }
+    }
+    return true;
 }
 // Ensure all objects in the pdf file, including those in indirect references, appear in the object
@@ -461,9 +1541,9 @@ QPDF::fixDanglingReferences(bool force)
     if (m->fixed_dangling_refs) {
         return;
     }
-    if (!m->objects.xref_table().resolve()) {
+    if (!m->xref_table.resolve()) {
         QTC::TC("qpdf", "QPDF fix dangling triggered xref reconstruction");
-        m->objects.xref_table().resolve();
+        m->xref_table.resolve();
     }
     m->fixed_dangling_refs = true;
 }
@@ -474,13 +1554,24 @@ QPDF::getObjectCount()
     // This method returns the next available indirect object number. makeIndirectObject uses it for
     // this purpose. After fixDanglingReferences is called, all objects in the xref table will also
     // be in obj_cache.
-    return toS(m->objects.next_id().getObj() - 1);
+    fixDanglingReferences();
+    QPDFObjGen og;
+    if (!m->obj_cache.empty()) {
+        og = (*(m->obj_cache.rbegin())).first;
+    }
+    return toS(og.getObj());
 }
 std::vector<QPDFObjectHandle>
 QPDF::getAllObjects()
 {
-    return m->objects.all();
+    // After fixDanglingReferences is called, all objects are in the object cache.
+    fixDanglingReferences();
+    std::vector<QPDFObjectHandle> result;
+    for (auto const& iter: m->obj_cache) {
+        result.push_back(newIndirect(iter.first, iter.second.object));
+    }
+    return result;
 }
 void
@@ -498,6 +1589,220 @@ QPDF::setLastObjectDescription(std::string const&amp; description, QPDFObjGen const&amp;
     }
 }
+QPDFObjectHandle
+QPDF::Xref_table::read_trailer()
+{
+    qpdf_offset_t offset = file->tell();
+    bool empty = false;
+    auto object = QPDFParser(*file, "trailer", tokenizer, nullptr, &qpdf, true).parse(empty, false);
+    if (empty) {
+        // Nothing in the PDF spec appears to allow empty objects, but they have been encountered in
+        // actual PDF files and Adobe Reader appears to ignore them.
+        qpdf.warn(qpdf.damagedPDF("trailer", "empty object treated as null"));
+    } else if (object.isDictionary() && read_token().isWord("stream")) {
+        qpdf.warn(qpdf.damagedPDF("trailer", file->tell(), "stream keyword found in trailer"));
+    }
+    // Override last_offset so that it points to the beginning of the object we just read
+    file->setLastOffset(offset);
+    return object;
+}
+
+QPDFObjectHandle
+QPDF::readObject(std::string const& description, QPDFObjGen og)
+{
+    setLastObjectDescription(description, og);
+    qpdf_offset_t offset = m->file->tell();
+    bool empty = false;
+
+    StringDecrypter decrypter{this, og};
+    StringDecrypter* decrypter_ptr = m->encp->encrypted ? &decrypter : nullptr;
+    auto object =
+        QPDFParser(*m->file, m->last_object_description, m->tokenizer, decrypter_ptr, this, true)
+            .parse(empty, false);
+    if (empty) {
+        // Nothing in the PDF spec appears to allow empty objects, but they have been encountered in
+        // actual PDF files and Adobe Reader appears to ignore them.
+        warn(damagedPDF(*m->file, m->file->getLastOffset(), "empty object treated as null"));
+        return object;
+    }
+    auto token = readToken(*m->file);
+    if (object.isDictionary() && token.isWord("stream")) {
+        readStream(object, og, offset);
+        token = readToken(*m->file);
+    }
+    if (!token.isWord("endobj")) {
+        QTC::TC("qpdf", "QPDF err expected endobj");
+        warn(damagedPDF("expected endobj"));
+    }
+    return object;
+}
+
+// After reading stream dictionary and stream keyword, read rest of stream.
+void
+QPDF::readStream(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset)
+{
+    validateStreamLineEnd(object, og, offset);
+
+    // Must get offset before accessing any additional objects since resolving a previously
+    // unresolved indirect object will change file position.
+    qpdf_offset_t stream_offset = m->file->tell();
+    size_t length = 0;
+
+    try {
+        auto length_obj = object.getKey("/Length");
+
+        if (!length_obj.isInteger()) {
+            if (length_obj.isNull()) {
+                QTC::TC("qpdf", "QPDF stream without length");
+                throw damagedPDF(offset, "stream dictionary lacks /Length key");
+            }
+            QTC::TC("qpdf", "QPDF stream length not integer");
+            throw damagedPDF(offset, "/Length key in stream dictionary is not an integer");
+        }
+
+        length = toS(length_obj.getUIntValue());
+        // Seek in two steps to avoid potential integer overflow
+        m->file->seek(stream_offset, SEEK_SET);
+        m->file->seek(toO(length), SEEK_CUR);
+        if (!readToken(*m->file).isWord("endstream")) {
+            QTC::TC("qpdf", "QPDF missing endstream");
+            throw damagedPDF("expected endstream");
+        }
+    } catch (QPDFExc& e) {
+        if (m->attempt_recovery) {
+            warn(e);
+            length = recoverStreamLength(m->file_sp, og, stream_offset);
+        } else {
+            throw;
+        }
+    }
+    object = {QPDF_Stream::create(this, og, object, stream_offset, length)};
+}
+
+void
+QPDF::validateStreamLineEnd(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset)
+{
+    // The PDF specification states that the word "stream" should be followed by either a carriage
+    // return and a newline or by a newline alone.  It specifically disallowed following it by a
+    // carriage return alone since, in that case, there would be no way to tell whether the NL in a
+    // CR NL sequence was part of the stream data.  However, some readers, including Adobe reader,
+    // accept a carriage return by itself when followed by a non-newline character, so that's what
+    // we do here. We have also seen files that have extraneous whitespace between the stream
+    // keyword and the newline.
+    while (true) {
+        char ch;
+        if (m->file->read(&ch, 1) == 0) {
+            // A premature EOF here will result in some other problem that will get reported at
+            // another time.
+            return;
+        }
+        if (ch == '\n') {
+            // ready to read stream data
+            QTC::TC("qpdf", "QPDF stream with NL only");
+            return;
+        }
+        if (ch == '\r') {
+            // Read another character
+            if (m->file->read(&ch, 1) != 0) {
+                if (ch == '\n') {
+                    // Ready to read stream data
+                    QTC::TC("qpdf", "QPDF stream with CRNL");
+                } else {
+                    // Treat the \r by itself as the whitespace after endstream and start reading
+                    // stream data in spite of not having seen a newline.
+                    QTC::TC("qpdf", "QPDF stream with CR only");
+                    m->file->unreadCh(ch);
+                    warn(damagedPDF(
+                        m->file->tell(), "stream keyword followed by carriage return only"));
+                }
+            }
+            return;
+        }
+        if (!QUtil::is_space(ch)) {
+            QTC::TC("qpdf", "QPDF stream without newline");
+            m->file->unreadCh(ch);
+            warn(damagedPDF(
+                m->file->tell(), "stream keyword not followed by proper line terminator"));
+            return;
+        }
+        warn(damagedPDF(m->file->tell(), "stream keyword followed by extraneous whitespace"));
+    }
+}
+
+QPDFObjectHandle
+QPDF::readObjectInStream(std::shared_ptr<InputSource>& input, int obj)
+{
+    m->last_object_description.erase(7); // last_object_description starts with "object "
+    m->last_object_description += std::to_string(obj);
+    m->last_object_description += " 0";
+
+    bool empty = false;
+    auto object = QPDFParser(*input, m->last_object_description, m->tokenizer, nullptr, this, true)
+                      .parse(empty, false);
+    if (empty) {
+        // Nothing in the PDF spec appears to allow empty objects, but they have been encountered in
+        // actual PDF files and Adobe Reader appears to ignore them.
+        warn(damagedPDF(*input, input->getLastOffset(), "empty object treated as null"));
+    }
+    return object;
+}
+
+bool
+QPDF::findEndstream()
+{
+    // Find endstream or endobj. Position the input at that token.
+    auto t = readToken(*m->file, 20);
+    if (t.isWord("endobj") || t.isWord("endstream")) {
+        m->file->seek(m->file->getLastOffset(), SEEK_SET);
+        return true;
+    }
+    return false;
+}
+
+size_t
+QPDF::recoverStreamLength(
+    std::shared_ptr<InputSource> input, QPDFObjGen const& og, qpdf_offset_t stream_offset)
+{
+    // Try to reconstruct stream length by looking for endstream or endobj
+    warn(damagedPDF(*input, stream_offset, "attempting to recover stream length"));
+
+    PatternFinder ef(*this, &QPDF::findEndstream);
+    size_t length = 0;
+    if (m->file->findFirst("end", stream_offset, 0, ef)) {
+        length = toS(m->file->tell() - stream_offset);
+        // Reread endstream but, if it was endobj, don't skip that.
+        QPDFTokenizer::Token t = readToken(*m->file);
+        if (t.getValue() == "endobj") {
+            m->file->seek(m->file->getLastOffset(), SEEK_SET);
+        }
+    }
+
+    if (length) {
+        // Make sure this is inside this object
+        auto found = m->xref_table.at_offset(stream_offset + toO(length));
+        if (found == QPDFObjGen() || found == og) {
+            // If we are trying to recover an XRef stream the xref table will not contain and
+            // won't contain any entries, therefore we cannot check the found length. Otherwise we
+            // found endstream\nendobj within the space allowed for this object, so we're probably
+            // in good shape.
+        } else {
+            QTC::TC("qpdf", "QPDF found wrong endstream in recovery");
+            length = 0;
+        }
+    }
+
+    if (length == 0) {
+        warn(damagedPDF(
+            *input, stream_offset, "unable to recover stream data; treating stream as empty"));
+    } else {
+        warn(damagedPDF(
+            *input, stream_offset, "recovered stream length: " + std::to_string(length)));
+    }
+
+    QTC::TC("qpdf", "QPDF recovered stream length");
+    return length;
+}
+
 QPDFTokenizer::Token
 QPDF::readToken(InputSource& input, size_t max_len)
 {
@@ -505,38 +1810,393 @@ QPDF::readToken(InputSource&amp; input, size_t max_len)
 }
 QPDFObjectHandle
+QPDF::readObjectAtOffset(
+    bool try_recovery,
+    qpdf_offset_t offset,
+    std::string const& description,
+    QPDFObjGen exp_og,
+    QPDFObjGen& og,
+    bool skip_cache_if_in_xref)
+{
+    bool check_og = true;
+    if (exp_og.getObj() == 0) {
+        // This method uses an expect object ID of 0 to indicate that we don't know or don't care
+        // what the actual object ID is at this offset. This is true when we read the xref stream
+        // and linearization hint streams. In this case, we don't verify the expect object
+        // ID/generation against what was read from the file. There is also no reason to attempt
+        // xref recovery if we get a failure in this case since the read attempt was not triggered
+        // by an xref lookup.
+        check_og = false;
+        try_recovery = false;
+    }
+    setLastObjectDescription(description, exp_og);
+
+    if (!m->attempt_recovery) {
+        try_recovery = false;
+    }
+
+    // Special case: if offset is 0, just return null.  Some PDF writers, in particular
+    // "Mac OS X 10.7.5 Quartz PDFContext", may store deleted objects in the xref table as
+    // "0000000000 00000 n", which is not correct, but it won't hurt anything for us to ignore
+    // these.
+    if (offset == 0) {
+        QTC::TC("qpdf", "QPDF bogus 0 offset", 0);
+        warn(damagedPDF(0, "object has offset 0"));
+        return QPDFObjectHandle::newNull();
+    }
+
+    m->file->seek(offset, SEEK_SET);
+    try {
+        QPDFTokenizer::Token tobjid = readToken(*m->file);
+        bool objidok = tobjid.isInteger();
+        QTC::TC("qpdf", "QPDF check objid", objidok ? 1 : 0);
+        if (!objidok) {
+            QTC::TC("qpdf", "QPDF expected n n obj");
+            throw damagedPDF(offset, "expected n n obj");
+        }
+        QPDFTokenizer::Token tgen = readToken(*m->file);
+        bool genok = tgen.isInteger();
+        QTC::TC("qpdf", "QPDF check generation", genok ? 1 : 0);
+        if (!genok) {
+            throw damagedPDF(offset, "expected n n obj");
+        }
+        QPDFTokenizer::Token tobj = readToken(*m->file);
+
+        bool objok = tobj.isWord("obj");
+        QTC::TC("qpdf", "QPDF check obj", objok ? 1 : 0);
+
+        if (!objok) {
+            throw damagedPDF(offset, "expected n n obj");
+        }
+        int objid = QUtil::string_to_int(tobjid.getValue().c_str());
+        int generation = QUtil::string_to_int(tgen.getValue().c_str());
+        og = QPDFObjGen(objid, generation);
+        if (objid == 0) {
+            QTC::TC("qpdf", "QPDF object id 0");
+            throw damagedPDF(offset, "object with ID 0");
+        }
+        if (check_og && (exp_og != og)) {
+            QTC::TC("qpdf", "QPDF err wrong objid/generation");
+            QPDFExc e = damagedPDF(offset, "expected " + exp_og.unparse(' ') + " obj");
+            if (try_recovery) {
+                // Will be retried below
+                throw e;
+            } else {
+                // We can try reading the object anyway even if the ID doesn't match.
+                warn(e);
+            }
+        }
+    } catch (QPDFExc& e) {
+        if (try_recovery) {
+            // Try again after reconstructing xref table
+            m->xref_table.reconstruct(e);
+            if (m->xref_table.type(exp_og) == 1) {
+                QTC::TC("qpdf", "QPDF recovered in readObjectAtOffset");
+                return readObjectAtOffset(
+                    false, m->xref_table.offset(exp_og), description, exp_og, og, false);
+            } else {
+                QTC::TC("qpdf", "QPDF object gone after xref reconstruction");
+                warn(damagedPDF(
+                    "",
+                    0,
+                    ("object " + exp_og.unparse(' ') +
+                     " not found in file after regenerating cross reference table")));
+                return QPDFObjectHandle::newNull();
+            }
+        } else {
+            throw;
+        }
+    }
+
+    QPDFObjectHandle oh = readObject(description, og);
+
+    if (isUnresolved(og)) {
+        // Store the object in the cache here so it gets cached whether we first know the offset or
+        // whether we first know the object ID and generation (in which we case we would get here
+        // through resolve).
+
+        // Determine the end offset of this object before and after white space.  We use these
+        // numbers to validate linearization hint tables.  Offsets and lengths of objects may imply
+        // the end of an object to be anywhere between these values.
+        qpdf_offset_t end_before_space = m->file->tell();
+
+        // skip over spaces
+        while (true) {
+            char ch;
+            if (m->file->read(&ch, 1)) {
+                if (!isspace(static_cast<unsigned char>(ch))) {
+                    m->file->seek(-1, SEEK_CUR);
+                    break;
+                }
+            } else {
+                throw damagedPDF(m->file->tell(), "EOF after endobj");
+            }
+        }
+        qpdf_offset_t end_after_space = m->file->tell();
+        if (skip_cache_if_in_xref && m->xref_table.type(og)) {
+            // Ordinarily, an object gets read here when resolved through xref table or stream. In
+            // the special case of the xref stream and linearization hint tables, the offset comes
+            // from another source. For the specific case of xref streams, the xref stream is read
+            // and loaded into the object cache very early in parsing. Ordinarily, when a file is
+            // updated by appending, items inserted into the xref table in later updates take
+            // precedence over earlier items. In the special case of reusing the object number
+            // previously used as the xref stream, we have the following order of events:
+            //
+            // * reused object gets loaded into the xref table
+            // * old object is read here while reading xref streams
+            // * original xref entry is ignored (since already in xref table)
+            //
+            // It is the second step that causes a problem. Even though the xref table is correct in
+            // this case, the old object is already in the cache and so effectively prevails over
+            // the reused object. To work around this issue, we have a special case for the xref
+            // stream (via the skip_cache_if_in_xref): if the object is already in the xref stream,
+            // don't cache what we read here.
+            //
+            // It is likely that the same bug may exist for linearization hint tables, but the
+            // existing code uses end_before_space and end_after_space from the cache, so fixing
+            // that would require more significant rework. The chances of a linearization hint
+            // stream being reused seems smaller because the xref stream is probably the highest
+            // object in the file and the linearization hint stream would be some random place in
+            // the middle, so I'm leaving that bug unfixed for now. If the bug were to be fixed, we
+            // could use !check_og in place of skip_cache_if_in_xref.
+            QTC::TC("qpdf", "QPDF skipping cache for known unchecked object");
+        } else {
+            m->xref_table.linearization_offsets(
+                toS(og.getObj()), end_before_space, end_after_space);
+            updateCache(og, oh.getObj());
+        }
+    }
+
+    return oh;
+}
+
+QPDFObject*
+QPDF::resolve(QPDFObjGen og)
+{
+    if (!isUnresolved(og)) {
+        return m->obj_cache[og].object.get();
+    }
+
+    if (m->resolving.count(og)) {
+        // This can happen if an object references itself directly or indirectly in some key that
+        // has to be resolved during object parsing, such as stream length.
+        QTC::TC("qpdf", "QPDF recursion loop in resolve");
+        warn(damagedPDF("", "loop detected resolving object " + og.unparse(' ')));
+        updateCache(og, QPDF_Null::create());
+        return m->obj_cache[og].object.get();
+    }
+    ResolveRecorder rr(this, og);
+
+    try {
+        switch (m->xref_table.type(og)) {
+        case 0:
+            break;
+        case 1:
+            {
+                // Object stored in cache by readObjectAtOffset
+                QPDFObjGen a_og;
+                QPDFObjectHandle oh =
+                    readObjectAtOffset(true, m->xref_table.offset(og), "", og, a_og, false);
+            }
+            break;
+
+        case 2:
+            resolveObjectsInStream(m->xref_table.stream_number(og.getObj()));
+            break;
+
+        default:
+            throw damagedPDF(
+                "", 0, ("object " + og.unparse('/') + " has unexpected xref entry type"));
+        }
+    } catch (QPDFExc& e) {
+        warn(e);
+    } catch (std::exception& e) {
+        warn(damagedPDF(
+            "", 0, ("object " + og.unparse('/') + ": error reading object: " + e.what())));
+    }
+
+    if (isUnresolved(og)) {
+        // PDF spec says unknown objects resolve to the null object.
+        QTC::TC("qpdf", "QPDF resolve failure to null");
+        updateCache(og, QPDF_Null::create());
+    }
+
+    auto result(m->obj_cache[og].object);
+    result->setDefaultDescription(this, og);
+    return result.get();
+}
+
+void
+QPDF::resolveObjectsInStream(int obj_stream_number)
+{
+    if (m->resolved_object_streams.count(obj_stream_number)) {
+        return;
+    }
+    m->resolved_object_streams.insert(obj_stream_number);
+    // Force resolution of object stream
+    QPDFObjectHandle obj_stream = getObjectByID(obj_stream_number, 0);
+    if (!obj_stream.isStream()) {
+        throw damagedPDF(
+            "supposed object stream " + std::to_string(obj_stream_number) + " is not a stream");
+    }
+
+    QPDFObjectHandle dict = obj_stream.getDict();
+    if (!dict.isDictionaryOfType("/ObjStm")) {
+        QTC::TC("qpdf", "QPDF ERR object stream with wrong type");
+        warn(damagedPDF(
+            "supposed object stream " + std::to_string(obj_stream_number) + " has wrong type"));
+    }
+
+    if (!(dict.getKey("/N").isInteger() && dict.getKey("/First").isInteger())) {
+        throw damagedPDF(
+            ("object stream " + std::to_string(obj_stream_number) + " has incorrect keys"));
+    }
+
+    int n = dict.getKey("/N").getIntValueAsInt();
+    int first = dict.getKey("/First").getIntValueAsInt();
+
+    std::map<int, int> offsets;
+
+    std::shared_ptr<Buffer> bp = obj_stream.getStreamData(qpdf_dl_specialized);
+    auto input = std::shared_ptr<InputSource>(
+        // line-break
+        new BufferInputSource(
+            (m->file->getName() + " object stream " + std::to_string(obj_stream_number)),
+            bp.get()));
+
+    qpdf_offset_t last_offset = -1;
+    for (int i = 0; i < n; ++i) {
+        QPDFTokenizer::Token tnum = readToken(*input);
+        QPDFTokenizer::Token toffset = readToken(*input);
+        if (!(tnum.isInteger() && toffset.isInteger())) {
+            throw damagedPDF(
+                *input,
+                m->last_object_description,
+                input->getLastOffset(),
+                "expected integer in object stream header");
+        }
+
+        int num = QUtil::string_to_int(tnum.getValue().c_str());
+        long long offset = QUtil::string_to_int(toffset.getValue().c_str());
+        if (num > m->xref_table.max_id()) {
+            continue;
+        }
+        if (num == obj_stream_number) {
+            QTC::TC("qpdf", "QPDF ignore self-referential object stream");
+            warn(damagedPDF(
+                *input,
+                m->last_object_description,
+                input->getLastOffset(),
+                "object stream claims to contain itself"));
+            continue;
+        }
+        if (offset <= last_offset) {
+            throw damagedPDF(
+                *input,
+                m->last_object_description,
+                input->getLastOffset(),
+                "expected offsets in object stream to be increasing");
+        }
+        last_offset = offset;
+
+        offsets[num] = toI(offset + first);
+    }
+
+    // To avoid having to read the object stream multiple times, store all objects that would be
+    // found here in the cache.  Remember that some objects stored here might have been overridden
+    // by new objects appended to the file, so it is necessary to recheck the xref table and only
+    // cache what would actually be resolved here.
+    m->last_object_description.clear();
+    m->last_object_description += "object ";
+    for (auto const& iter: offsets) {
+        QPDFObjGen og(iter.first, 0);
+        if (m->xref_table.type(og) == 2 &&
+            m->xref_table.stream_number(og.getObj()) == obj_stream_number) {
+            int offset = iter.second;
+            input->seek(offset, SEEK_SET);
+            QPDFObjectHandle oh = readObjectInStream(input, iter.first);
+            updateCache(og, oh.getObj());
+        } else {
+            QTC::TC("qpdf", "QPDF not caching overridden objstm object");
+        }
+    }
+}
+
+QPDFObjectHandle
 QPDF::newIndirect(QPDFObjGen const& og, std::shared_ptr<QPDFObject> const& obj)
 {
     obj->setDefaultDescription(this, og);
     return {obj};
 }
+void
+QPDF::updateCache(QPDFObjGen const& og, std::shared_ptr<QPDFObject> const& object)
+{
+    object->setObjGen(this, og);
+    if (isCached(og)) {
+        auto& cache = m->obj_cache[og];
+        cache.object->assign(object);
+    } else {
+        m->obj_cache[og] = ObjCache(object);
+    }
+}
+
+bool
+QPDF::isCached(QPDFObjGen const& og)
+{
+    return m->obj_cache.count(og) != 0;
+}
+
+bool
+QPDF::isUnresolved(QPDFObjGen const& og)
+{
+    return !isCached(og) || m->obj_cache[og].object->isUnresolved();
+}
+
+QPDFObjGen
+QPDF::nextObjGen()
+{
+    int max_objid = toI(getObjectCount());
+    if (max_objid == std::numeric_limits<int>::max()) {
+        throw std::range_error("max object id is too high to create new objects");
+    }
+    return QPDFObjGen(max_objid + 1, 0);
+}
+
+QPDFObjectHandle
+QPDF::makeIndirectFromQPDFObject(std::shared_ptr<QPDFObject> const& obj)
+{
+    QPDFObjGen next{nextObjGen()};
+    m->obj_cache[next] = ObjCache(obj);
+    return newIndirect(next, m->obj_cache[next].object);
+}
+
 QPDFObjectHandle
 QPDF::makeIndirectObject(QPDFObjectHandle oh)
 {
     if (!oh) {
         throw std::logic_error("attempted to make an uninitialized QPDFObjectHandle indirect");
     }
-    return m->objects.make_indirect(oh.getObj());
+    return makeIndirectFromQPDFObject(oh.getObj());
 }
 QPDFObjectHandle
 QPDF::newReserved()
 {
-    return m->objects.make_indirect(QPDF_Reserved::create());
+    return makeIndirectFromQPDFObject(QPDF_Reserved::create());
 }
 QPDFObjectHandle
 QPDF::newIndirectNull()
 {
-    return m->objects.make_indirect(QPDF_Null::create());
+    return makeIndirectFromQPDFObject(QPDF_Null::create());
 }
 QPDFObjectHandle
 QPDF::newStream()
 {
-    return m->objects.make_indirect(
-        QPDF_Stream::create(this, m->objects.next_id(), QPDFObjectHandle::newDictionary(), 0, 0));
+    return makeIndirectFromQPDFObject(
+        QPDF_Stream::create(this, nextObjGen(), QPDFObjectHandle::newDictionary(), 0, 0));
 }
 QPDFObjectHandle
@@ -555,40 +2215,93 @@ QPDF::newStream(std::string const&amp; data)
     return result;
 }
+std::shared_ptr<QPDFObject>
+QPDF::getObjectForParser(int id, int gen, bool parse_pdf)
+{
+    // This method is called by the parser and therefore must not resolve any objects.
+    auto og = QPDFObjGen(id, gen);
+    if (auto iter = m->obj_cache.find(og); iter != m->obj_cache.end()) {
+        return iter->second.object;
+    }
+    if (m->xref_table.type(og) || !m->xref_table.initialized()) {
+        return m->obj_cache.insert({og, QPDF_Unresolved::create(this, og)}).first->second.object;
+    }
+    if (parse_pdf) {
+        return QPDF_Null::create();
+    }
+    return m->obj_cache.insert({og, QPDF_Null::create(this, og)}).first->second.object;
+}
+
+std::shared_ptr<QPDFObject>
+QPDF::getObjectForJSON(int id, int gen)
+{
+    auto og = QPDFObjGen(id, gen);
+    auto [it, inserted] = m->obj_cache.try_emplace(og);
+    auto& obj = it->second.object;
+    if (inserted) {
+        obj = (m->xref_table.initialized() && !m->xref_table.type(og))
+            ? QPDF_Null::create(this, og)
+            : QPDF_Unresolved::create(this, og);
+    }
+    return obj;
+}
+
 QPDFObjectHandle
 QPDF::getObject(QPDFObjGen const& og)
 {
-    return m->objects.get(og);
+    if (auto it = m->obj_cache.find(og); it != m->obj_cache.end()) {
+        return {it->second.object};
+    } else if (m->xref_table.initialized() && !m->xref_table.type(og)) {
+        return QPDF_Null::create();
+    } else {
+        auto result = m->obj_cache.try_emplace(og, QPDF_Unresolved::create(this, og));
+        return {result.first->second.object};
+    }
 }
 QPDFObjectHandle
-QPDF::getObject(int id, int gen)
+QPDF::getObject(int objid, int generation)
 {
-    return m->objects.get(id, gen);
+    return getObject(QPDFObjGen(objid, generation));
 }
 QPDFObjectHandle
 QPDF::getObjectByObjGen(QPDFObjGen const& og)
 {
-    return m->objects.get(og);
+    return getObject(og);
 }
 QPDFObjectHandle
-QPDF::getObjectByID(int id, int gen)
+QPDF::getObjectByID(int objid, int generation)
+{
+    return getObject(QPDFObjGen(objid, generation));
+}
+
+void
+QPDF::replaceObject(int objid, int generation, QPDFObjectHandle oh)
 {
-    return m->objects.get(id, gen);
+    replaceObject(QPDFObjGen(objid, generation), oh);
 }
 void
-QPDF::replaceObject(int id, int gen, QPDFObjectHandle replacement)
+QPDF::replaceObject(QPDFObjGen const& og, QPDFObjectHandle oh)
 {
-    m->objects.replace(QPDFObjGen(id, gen), replacement);
+    if (!oh || (oh.isIndirect() && !(oh.isStream() && oh.getObjGen() == og))) {
+        QTC::TC("qpdf", "QPDF replaceObject called with indirect object");
+        throw std::logic_error("QPDF::replaceObject called with indirect object handle");
+    }
+    updateCache(og, oh.getObj());
 }
 void
-QPDF::replaceObject(QPDFObjGen const& og, QPDFObjectHandle replacement)
+QPDF::removeObject(QPDFObjGen og)
 {
-    m->objects.replace(og, replacement);
+    if (auto cached = m->obj_cache.find(og); cached != m->obj_cache.end()) {
+        // Take care of any object handles that may be floating around.
+        cached->second.object->assign(QPDF_Null::create());
+        cached->second.object->setObjGen(nullptr, QPDFObjGen());
+        m->obj_cache.erase(cached);
+    }
 }
 void
@@ -599,7 +2312,7 @@ QPDF::replaceReserved(QPDFObjectHandle reserved, QPDFObjectHandle replacement)
     if (!(tc == ::ot_reserved || tc == ::ot_null)) {
         throw std::logic_error("replaceReserved called with non-reserved object");
     }
-    m->objects.replace(reserved.getObjGen(), replacement);
+    replaceObject(reserved.getObjGen(), replacement);
 }
 QPDFObjectHandle
@@ -865,13 +2578,16 @@ QPDF::copyStreamData(QPDFObjectHandle result, QPDFObjectHandle foreign)
 void
 QPDF::swapObjects(int objid1, int generation1, int objid2, int generation2)
 {
-    m->objects.swap(QPDFObjGen(objid1, generation1), QPDFObjGen(objid2, generation2));
+    swapObjects(QPDFObjGen(objid1, generation1), QPDFObjGen(objid2, generation2));
 }
 void
 QPDF::swapObjects(QPDFObjGen const& og1, QPDFObjGen const& og2)
 {
-    m->objects.swap(og1, og2);
+    // Force objects to be read from the input source if needed, then swap them in the cache.
+    resolve(og1);
+    resolve(og2);
+    m->obj_cache[og1].object->swapWith(m->obj_cache[og2].object);
 }
 unsigned long long
@@ -932,13 +2648,13 @@ QPDF::getExtensionLevel()
 QPDFObjectHandle
 QPDF::getTrailer()
 {
-    return m->objects.trailer();
+    return m->xref_table.trailer();
 }
 QPDFObjectHandle
 QPDF::getRoot()
 {
-    auto root = m->objects.trailer().getKey("/Root");
+    QPDFObjectHandle root = m->xref_table.trailer().getKey("/Root");
     if (!root.isDictionary()) {
         throw damagedPDF("", 0, "unable to find /Root dictionary");
     } else if (
@@ -954,10 +2670,141 @@ QPDF::getRoot()
 std::map<QPDFObjGen, QPDFXRefEntry>
 QPDF::getXRefTable()
 {
-    if (!m->objects.xref_table().initialized()) {
+    if (!m->xref_table.initialized()) {
         throw std::logic_error("QPDF::getXRefTable called before parsing.");
     }
-    return m->objects.xref_table().as_map();
+    return m->xref_table.as_map();
+}
+
+size_t
+QPDF::tableSize()
+{
+    // If obj_cache is dense, accommodate all object in tables,else accommodate only original
+    // objects.
+    auto max_xref = toI(m->xref_table.size());
+    if (max_xref > 0) {
+        --max_xref;
+    }
+    auto max_obj = m->obj_cache.size() ? m->obj_cache.crbegin()->first.getObj() : 0;
+    auto max_id = std::numeric_limits<int>::max() - 1;
+    if (max_obj >= max_id || max_xref >= max_id) {
+        // Temporary fix. Long-term solution is
+        // - QPDFObjGen to enforce objgens are valid and sensible
+        // - xref table and obj cache to protect against insertion of impossibly large obj ids
+        stopOnError("Impossibly large object id encountered.");
+    }
+    if (max_obj < 1.1 * std::max(toI(m->obj_cache.size()), max_xref)) {
+        return toS(++max_obj);
+    }
+    return toS(++max_xref);
+}
+
+std::vector<QPDFObjGen>
+QPDF::getCompressibleObjVector()
+{
+    return getCompressibleObjGens<QPDFObjGen>();
+}
+
+std::vector<bool>
+QPDF::getCompressibleObjSet()
+{
+    return getCompressibleObjGens<bool>();
+}
+
+template <typename T>
+std::vector<T>
+QPDF::getCompressibleObjGens()
+{
+    // Return a list of objects that are allowed to be in object streams.  Walk through the objects
+    // by traversing the document from the root, including a traversal of the pages tree.  This
+    // makes that objects that are on the same page are more likely to be in the same object stream,
+    // which is slightly more efficient, particularly with linearized files.  This is better than
+    // iterating through the xref table since it avoids preserving orphaned items.
+
+    // Exclude encryption dictionary, if any
+    QPDFObjectHandle encryption_dict = m->xref_table.trailer().getKey("/Encrypt");
+    QPDFObjGen encryption_dict_og = encryption_dict.getObjGen();
+
+    const size_t max_obj = getObjectCount();
+    std::vector<bool> visited(max_obj, false);
+    std::vector<QPDFObjectHandle> queue;
+    queue.reserve(512);
+    queue.push_back(m->xref_table.trailer());
+    std::vector<T> result;
+    if constexpr (std::is_same_v<T, QPDFObjGen>) {
+        result.reserve(m->obj_cache.size());
+    } else if constexpr (std::is_same_v<T, bool>) {
+        result.resize(max_obj + 1U, false);
+    } else {
+        throw std::logic_error("Unsupported type in QPDF::getCompressibleObjGens");
+    }
+    while (!queue.empty()) {
+        auto obj = queue.back();
+        queue.pop_back();
+        if (obj.getObjectID() > 0) {
+            QPDFObjGen og = obj.getObjGen();
+            const size_t id = toS(og.getObj() - 1);
+            if (id >= max_obj) {
+                throw std::logic_error(
+                    "unexpected object id encountered in getCompressibleObjGens");
+            }
+            if (visited[id]) {
+                QTC::TC("qpdf", "QPDF loop detected traversing objects");
+                continue;
+            }
+
+            // Check whether this is the current object. If not, remove it (which changes it into a
+            // direct null and therefore stops us from revisiting it) and move on to the next object
+            // in the queue.
+            auto upper = m->obj_cache.upper_bound(og);
+            if (upper != m->obj_cache.end() && upper->first.getObj() == og.getObj()) {
+                removeObject(og);
+                continue;
+            }
+
+            visited[id] = true;
+
+            if (og == encryption_dict_og) {
+                QTC::TC("qpdf", "QPDF exclude encryption dictionary");
+            } else if (!(obj.isStream() ||
+                         (obj.isDictionaryOfType("/Sig") && obj.hasKey("/ByteRange") &&
+                          obj.hasKey("/Contents")))) {
+                if constexpr (std::is_same_v<T, QPDFObjGen>) {
+                    result.push_back(og);
+                } else if constexpr (std::is_same_v<T, bool>) {
+                    result[id + 1U] = true;
+                }
+            }
+        }
+        if (obj.isStream()) {
+            QPDFObjectHandle dict = obj.getDict();
+            std::set<std::string> keys = dict.getKeys();
+            for (auto iter = keys.rbegin(); iter != keys.rend(); ++iter) {
+                std::string const& key = *iter;
+                QPDFObjectHandle value = dict.getKey(key);
+                if (key == "/Length") {
+                    // omit stream lengths
+                    if (value.isIndirect()) {
+                        QTC::TC("qpdf", "QPDF exclude indirect length");
+                    }
+                } else {
+                    queue.push_back(value);
+                }
+            }
+        } else if (obj.isDictionary()) {
+            std::set<std::string> keys = obj.getKeys();
+            for (auto iter = keys.rbegin(); iter != keys.rend(); ++iter) {
+                queue.push_back(obj.getKey(*iter));
+            }
+        } else if (obj.isArray()) {
+            int n = obj.getArrayNItems();
+            for (int i = 1; i <= n; ++i) {
+                queue.push_back(obj.getArrayItem(n - i));
+            }
+        }
+    }
+
+    return result;
 }
 bool
@@ -727,7 +727,7 @@ QPDF::initializeEncryption()
     // at /Encrypt again.  Otherwise, things could go wrong if someone mutates the encryption
     // dictionary.
-    if (!m->objects.trailer().hasKey("/Encrypt")) {
+    if (!m->xref_table.trailer().hasKey("/Encrypt")) {
         return;
     }
@@ -736,7 +736,7 @@ QPDF::initializeEncryption()
     m->encp->encrypted = true;
     std::string id1;
-    QPDFObjectHandle id_obj = m->objects.trailer().getKey("/ID");
+    QPDFObjectHandle id_obj = m->xref_table.trailer().getKey("/ID");
     if ((id_obj.isArray() && (id_obj.getArrayNItems() == 2) && id_obj.getArrayItem(0).isString())) {
         id1 = id_obj.getArrayItem(0).getStringValue();
     } else {
@@ -745,7 +745,7 @@ QPDF::initializeEncryption()
         warn(damagedPDF("trailer", "invalid /ID in trailer dictionary"));
     }
-    QPDFObjectHandle encryption_dict = m->objects.trailer().getKey("/Encrypt");
+    QPDFObjectHandle encryption_dict = m->xref_table.trailer().getKey("/Encrypt");
     if (!encryption_dict.isDictionary()) {
         throw damagedPDF("/Encrypt in trailer dictionary is not a dictionary");
     }
@@ -536,7 +536,7 @@ QPDF::JSONReactor::dictionaryItem(std::string const&amp; key, JSON const&amp; value)
         } else if (is_obj_key(key, obj, gen)) {
             this->cur_object = key;
             if (setNextStateIfDictionary(key, value, st_object_top)) {
-                next_obj = pdf.objects().get_for_json(obj, gen);
+                next_obj = pdf.getObjectForJSON(obj, gen);
             }
         } else {
             QTC::TC("qpdf", "QPDF_json bad object key");
@@ -582,7 +582,7 @@ QPDF::JSONReactor::dictionaryItem(std::string const&amp; key, JSON const&amp; value)
             this->saw_value = true;
             // The trailer must be a dictionary, so we can use setNextStateIfDictionary.
             if (setNextStateIfDictionary("trailer.value", value, st_object)) {
-                pdf.m->objects.xref_table().trailer(makeObject(value));
+                pdf.m->xref_table.trailer(makeObject(value));
             }
         } else if (key == "stream") {
             // Don't need to set saw_stream here since there's already an error.
@@ -740,7 +740,7 @@ QPDF::JSONReactor::makeObject(JSON const&amp; value)
         int gen = 0;
         std::string str;
         if (is_indirect_object(str_v, obj, gen)) {
-            result = pdf.objects().get_for_json(obj, gen);
+            result = pdf.getObjectForJSON(obj, gen);
         } else if (is_unicode_string(str_v, str)) {
             result = QPDFObjectHandle::newUnicodeString(str);
         } else if (is_binary_string(str_v, str)) {
@@ -776,7 +776,7 @@ QPDF::createFromJSON(std::shared_ptr&lt;InputSource&gt; is)
 {
     m->pdf_version = "1.3";
     m->no_input_name = is->getName();
-    m->objects.xref_table().initialize_json();
+    m->xref_table.initialize_json();
     importJSON(is, true);
 }
@@ -130,7 +130,7 @@ QPDF::isLinearized()
         return false;
     }
-    auto candidate = m->objects.get(lindict_obj, 0);
+    auto candidate = getObjectByID(lindict_obj, 0);
     if (!candidate.isDictionary()) {
         return false;
     }
@@ -287,9 +287,9 @@ QPDF::readHintStream(Pipeline&amp; pl, qpdf_offset_t offset, size_t length)
 {
     QPDFObjGen og;
     QPDFObjectHandle H =
-        objects().read(false, offset, "linearization hint stream", QPDFObjGen(0, 0), og, false);
-    qpdf_offset_t min_end_offset = m->objects.xref_table().end_before_space(og);
-    qpdf_offset_t max_end_offset = m->objects.xref_table().end_after_space(og);
+        readObjectAtOffset(false, offset, "linearization hint stream", QPDFObjGen(0, 0), og, false);
+    qpdf_offset_t min_end_offset = m->xref_table.end_before_space(og);
+    qpdf_offset_t max_end_offset = m->xref_table.end_after_space(og);
     if (!H.isStream()) {
         throw damagedPDF("linearization dictionary", "hint table is not a stream");
     }
@@ -303,8 +303,8 @@ QPDF::readHintStream(Pipeline&amp; pl, qpdf_offset_t offset, size_t length)
     auto length_og = Hdict.getKey("/Length").getObjGen();
     if (length_og.isIndirect()) {
         QTC::TC("qpdf", "QPDF hint table length indirect");
-        min_end_offset = m->objects.xref_table().end_before_space(length_og);
-        max_end_offset = m->objects.xref_table().end_after_space(length_og);
+        min_end_offset = m->xref_table.end_before_space(length_og);
+        max_end_offset = m->xref_table.end_after_space(length_og);
     } else {
         QTC::TC("qpdf", "QPDF hint table length direct");
     }
@@ -441,7 +441,7 @@ QPDF::checkLinearizationInternal()
     for (size_t i = 0; i < toS(npages); ++i) {
         QPDFObjectHandle const& page = pages.at(i);
         QPDFObjGen og(page.getObjGen());
-        if (m->objects.xref_table().type(og) == 2) {
+        if (m->xref_table.type(og) == 2) {
             linearizationWarning(
                 "page dictionary for page " + std::to_string(i) + " is compressed");
         }
@@ -457,11 +457,11 @@ QPDF::checkLinearizationInternal()
             break;
         }
     }
-    if (m->file->tell() != m->objects.xref_table().first_item_offset()) {
+    if (m->file->tell() != m->xref_table.first_item_offset()) {
         QTC::TC("qpdf", "QPDF err /T mismatch");
         linearizationWarning(
             "space before first xref item (/T) mismatch (computed = " +
-            std::to_string(m->objects.xref_table().first_item_offset()) +
+            std::to_string(m->xref_table.first_item_offset()) +
             "; file = " + std::to_string(m->file->tell()));
     }
@@ -472,7 +472,7 @@ QPDF::checkLinearizationInternal()
     // compressed objects are supposed to be at the end of the containing xref section if any object
     // streams are in use.
-    if (m->objects.xref_table().uncompressed_after_compressed()) {
+    if (m->xref_table.uncompressed_after_compressed()) {
         linearizationWarning("linearized file contains an uncompressed object after a compressed "
                              "one in a cross-reference stream");
     }
@@ -481,8 +481,8 @@ QPDF::checkLinearizationInternal()
     // make changes.  If it has to, then the file is not properly linearized.  We use the xref table
     // to figure out which objects are compressed and which are uncompressed.
-    optimize(m->objects);
-    calculateLinearizationData(m->objects);
+    optimize(m->xref_table);
+    calculateLinearizationData(m->xref_table);
     // E: offset of end of first page -- Implementation note 123 says Acrobat includes on extra
     // object here by mistake.  pdlin fails to place thumbnail images in section 9, so when
@@ -499,8 +499,8 @@ QPDF::checkLinearizationInternal()
     qpdf_offset_t max_E = -1;
     for (auto const& oh: m->part6) {
         QPDFObjGen og(oh.getObjGen());
-        auto before = m->objects.xref_table().end_before_space(og);
-        auto after = m->objects.xref_table().end_after_space(og);
+        auto before = m->xref_table.end_before_space(og);
+        auto after = m->xref_table.end_after_space(og);
         if (before <= 0) {
             // All objects have to have been dereferenced to be classified.
             throw std::logic_error("linearization part6 object not in cache");
@@ -533,7 +533,7 @@ QPDF::maxEnd(ObjUser const&amp; ou)
     }
     qpdf_offset_t end = 0;
     for (auto const& og: m->obj_user_to_objects[ou]) {
-        auto e = m->objects.xref_table().end_after_space(og);
+        auto e = m->xref_table.end_after_space(og);
         if (e <= 0) {
             stopOnError("unknown object referenced in object user table");
         }
@@ -545,14 +545,13 @@ QPDF::maxEnd(ObjUser const&amp; ou)
 qpdf_offset_t
 QPDF::getLinearizationOffset(QPDFObjGen const& og)
 {
-    switch (m->objects.xref_table().type(og)) {
+    switch (m->xref_table.type(og)) {
     case 1:
-        return m->objects.xref_table().offset(og);
+        return m->xref_table.offset(og);
     case 2:
         // For compressed objects, return the offset of the object stream that contains them.
-        return getLinearizationOffset(
-            QPDFObjGen(m->objects.xref_table().stream_number(og.getObj()), 0));
+        return getLinearizationOffset(QPDFObjGen(m->xref_table.stream_number(og.getObj()), 0));
     default:
         stopOnError("getLinearizationOffset called for xref entry not of type 1 or 2");
@@ -563,22 +562,22 @@ QPDF::getLinearizationOffset(QPDFObjGen const&amp; og)
 QPDFObjectHandle
 QPDF::getUncompressedObject(QPDFObjectHandle& obj, std::map<int, int> const& object_stream_data)
 {
-    if (obj.isNull() || !object_stream_data.count(obj.getObjectID())) {
+    if (obj.isNull() || (object_stream_data.count(obj.getObjectID()) == 0)) {
         return obj;
     } else {
         int repl = (*(object_stream_data.find(obj.getObjectID()))).second;
-        return m->objects.get(repl, 0);
+        return getObject(repl, 0);
     }
 }
 QPDFObjectHandle
-QPDF::getUncompressedObject(QPDFObjectHandle& obj, Objects const& objects)
+QPDF::getUncompressedObject(QPDFObjectHandle& obj, Xref_table const& xref)
 {
     auto og = obj.getObjGen();
-    if (obj.isNull() || objects.xref_table().type(og) != 2) {
+    if (obj.isNull() || xref.type(og) != 2) {
         return obj;
     }
-    return m->objects.get(objects.xref_table().stream_number(og.getObj()), 0);
+    return getObject(xref.stream_number(og.getObj()), 0);
 }
 QPDFObjectHandle
@@ -586,7 +585,7 @@ QPDF::getUncompressedObject(QPDFObjectHandle&amp; oh, QPDFWriter::ObjTable const&amp; ob
 {
     if (obj.contains(oh)) {
         if (auto id = obj[oh].object_stream; id > 0) {
-            return oh.isNull() ? oh : m->objects.get(id, 0);
+            return oh.isNull() ? oh : getObject(id, 0);
         }
     }
     return oh;
@@ -598,7 +597,7 @@ QPDF::lengthNextN(int first_object, int n)
     int length = 0;
     for (int i = 0; i < n; ++i) {
         QPDFObjGen og(first_object + i, 0);
-        auto end = m->objects.xref_table().end_after_space(og);
+        auto end = m->xref_table.end_after_space(og);
         if (end <= 0) {
             linearizationWarning(
                 "no xref table entry for " + std::to_string(first_object + i) + " 0");
@@ -628,7 +627,7 @@ QPDF::checkHPageOffset(
     int npages = toI(pages.size());
     qpdf_offset_t table_offset = adjusted_offset(m->page_offset_hints.first_page_offset);
     QPDFObjGen first_page_og(pages.at(0).getObjGen());
-    if (m->objects.xref_table().type(first_page_og) == 0) {
+    if (m->xref_table.type(first_page_og) == 0) {
         stopOnError("supposed first page object is not known");
     }
     qpdf_offset_t offset = getLinearizationOffset(first_page_og);
@@ -639,7 +638,7 @@ QPDF::checkHPageOffset(
     for (int pageno = 0; pageno < npages; ++pageno) {
         QPDFObjGen page_og(pages.at(toS(pageno)).getObjGen());
         int first_object = page_og.getObj();
-        if (m->objects.xref_table().type(page_og) == 0) {
+        if (m->xref_table.type(page_og) == 0) {
             stopOnError("unknown object in page offset hint table");
         }
         offset = getLinearizationOffset(page_og);
@@ -761,7 +760,7 @@ QPDF::checkHSharedObject(std::vector&lt;QPDFObjectHandle&gt; const&amp; pages, std::map&lt;in
                 cur_object = so.first_shared_obj;
                 QPDFObjGen og(cur_object, 0);
-                if (m->objects.xref_table().type(og) == 0) {
+                if (m->xref_table.type(og) == 0) {
                     stopOnError("unknown object in shared object hint table");
                 }
                 qpdf_offset_t offset = getLinearizationOffset(og);
@@ -812,7 +811,7 @@ QPDF::checkHOutlines()
                 return;
             }
             QPDFObjGen og(outlines.getObjGen());
-            if (m->objects.xref_table().type(og) == 0) {
+            if (m->xref_table.type(og) == 0) {
                 stopOnError("unknown object in outlines hint table");
             }
             qpdf_offset_t offset = getLinearizationOffset(og);
@@ -1159,7 +1158,7 @@ QPDF::calculateLinearizationData(T const&amp; object_stream_data)
         // Map all page objects to the containing object stream.  This should be a no-op in a
         // properly linearized file.
         for (auto oh: getAllPages()) {
-            pages.emplace_back(getUncompressedObject(oh, object_stream_data));
+            pages.push_back(getUncompressedObject(oh, object_stream_data));
         }
     }
     int npages = toI(pages.size());
@@ -1430,9 +1429,9 @@ QPDF::pushOutlinesToPart(
     m->c_outline_data.first_object = outlines_og.getObj();
     m->c_outline_data.nobjects = 1;
     lc_outlines.erase(outlines_og);
-    part.emplace_back(outlines);
+    part.push_back(outlines);
     for (auto const& og: lc_outlines) {
-        part.emplace_back(m->objects.get(og));
+        part.push_back(getObject(og));
         ++m->c_outline_data.nobjects;
     }
 }
-#include <qpdf/qpdf-config.h> // include first for large file support
-
-#include <qpdf/QPDF_private.hh>
-
-#include <array>
-#include <cstring>
-#include <limits>
-#include <map>
-#include <vector>
-
-#include <qpdf/BufferInputSource.hh>
-#include <qpdf/OffsetInputSource.hh>
-#include <qpdf/Pipeline.hh>
-#include <qpdf/QPDFExc.hh>
-#include <qpdf/QPDFLogger.hh>
-#include <qpdf/QPDFObject_private.hh>
-#include <qpdf/QPDFParser.hh>
-#include <qpdf/QPDF_Array.hh>
-#include <qpdf/QPDF_Dictionary.hh>
-#include <qpdf/QPDF_Null.hh>
-#include <qpdf/QPDF_Reserved.hh>
-#include <qpdf/QPDF_Stream.hh>
-#include <qpdf/QPDF_Unresolved.hh>
-#include <qpdf/QTC.hh>
-#include <qpdf/QUtil.hh>
-
-using Objects = QPDF::Objects;
-using Xref_table = Objects::Xref_table;
-
-namespace
-{
-    class InvalidInputSource final: public InputSource
-    {
-      public:
-        InvalidInputSource(std::string const& name) :
-            name(name)
-        {
-        }
-        ~InvalidInputSource() final = default;
-        qpdf_offset_t
-        findAndSkipNextEOL() final
-        {
-            throwException();
-            return 0;
-        }
-        std::string const&
-        getName() const final
-        {
-            return name;
-        }
-        qpdf_offset_t
-        tell() final
-        {
-            throwException();
-            return 0;
-        }
-        void
-        seek(qpdf_offset_t offset, int whence) final
-        {
-            throwException();
-        }
-        void
-        rewind() final
-        {
-            throwException();
-        }
-        size_t
-        read(char* buffer, size_t length) final
-        {
-            throwException();
-            return 0;
-        }
-        void
-        unreadCh(char ch) final
-        {
-            throwException();
-        }
-
-      private:
-        void
-        throwException()
-        {
-            throw std::logic_error("QPDF operation attempted on a QPDF object with no input "
-                                   "source. QPDF operations are invalid before processFile (or "
-                                   "another process method) or after closeInputSource");
-        }
-
-        std::string const& name;
-    };
-} // namespace
-
-bool
-QPDF::findStartxref()
-{
-    if (readToken(*m->file).isWord("startxref") && readToken(*m->file).isInteger()) {
-        // Position in front of offset token
-        m->file->seek(m->file->getLastOffset(), SEEK_SET);
-        return true;
-    }
-    return false;
-}
-
-void
-Xref_table::initialize_empty()
-{
-    initialized_ = true;
-    trailer_ = QPDFObjectHandle::newDictionary();
-    auto rt = qpdf.makeIndirectObject(QPDFObjectHandle::newDictionary());
-    auto pgs = qpdf.makeIndirectObject(QPDFObjectHandle::newDictionary());
-    pgs.replaceKey("/Type", QPDFObjectHandle::newName("/Pages"));
-    pgs.replaceKey("/Kids", QPDFObjectHandle::newArray());
-    pgs.replaceKey("/Count", QPDFObjectHandle::newInteger(0));
-    rt.replaceKey("/Type", QPDFObjectHandle::newName("/Catalog"));
-    rt.replaceKey("/Pages", pgs);
-    trailer_.replaceKey("/Root", rt);
-    trailer_.replaceKey("/Size", QPDFObjectHandle::newInteger(3));
-}
-
-void
-Xref_table::initialize_json()
-{
-    initialized_ = true;
-    table.resize(1);
-    trailer_ = QPDFObjectHandle::newDictionary();
-    trailer_.replaceKey("/Size", QPDFObjectHandle::newInteger(1));
-}
-
-void
-Xref_table::initialize()
-{
-    // PDF spec says %%EOF must be found within the last 1024 bytes of/ the file.  We add an extra
-    // 30 characters to leave room for the startxref stuff.
-    file->seek(0, SEEK_END);
-    qpdf_offset_t end_offset = file->tell();
-    // Sanity check on object ids. All objects must appear in xref table / stream. In all realistic
-    // scenarios at least 3 bytes are required.
-    if (max_id_ > end_offset / 3) {
-        max_id_ = static_cast<int>(end_offset / 3);
-    }
-    qpdf_offset_t start_offset = (end_offset > 1054 ? end_offset - 1054 : 0);
-    PatternFinder sf(qpdf, &QPDF::findStartxref);
-    qpdf_offset_t xref_offset = 0;
-    if (file->findLast("startxref", start_offset, 0, sf)) {
-        xref_offset = QUtil::string_to_ll(read_token().getValue().c_str());
-    }
-
-    try {
-        if (xref_offset == 0) {
-            QTC::TC("qpdf", "QPDF can't find startxref");
-            throw damaged_pdf("can't find startxref");
-        }
-        try {
-            read(xref_offset);
-        } catch (QPDFExc&) {
-            throw;
-        } catch (std::exception& e) {
-            throw damaged_pdf(std::string("error reading xref: ") + e.what());
-        }
-    } catch (QPDFExc& e) {
-        if (attempt_recovery_) {
-            reconstruct(e);
-            QTC::TC("qpdf", "QPDF reconstructed xref table");
-        } else {
-            throw;
-        }
-    }
-
-    initialized_ = true;
-}
-
-void
-Xref_table::reconstruct(QPDFExc& e)
-{
-    if (reconstructed_) {
-        // Avoid xref reconstruction infinite loops. This is getting very hard to reproduce because
-        // qpdf is throwing many fewer exceptions while parsing. Most situations are warnings now.
-        throw e;
-    }
-
-    // If recovery generates more than 1000 warnings, the file is so severely damaged that there
-    // probably is no point trying to continue.
-    const auto max_warnings = qpdf.m->warnings.size() + 1000U;
-    auto check_warnings = [this, max_warnings]() {
-        if (qpdf.m->warnings.size() > max_warnings) {
-            throw damaged_pdf("too many errors while reconstructing cross-reference table");
-        }
-    };
-
-    reconstructed_ = true;
-    // We may find more objects, which may contain dangling references.
-    qpdf.m->fixed_dangling_refs = false;
-
-    warn_damaged("file is damaged");
-    qpdf.warn(e);
-    warn_damaged("Attempting to reconstruct cross-reference table");
-
-    // Delete all references to type 1 (uncompressed) objects
-    for (auto& iter: table) {
-        if (iter.type() == 1) {
-            iter = {};
-        }
-    }
-
-    std::vector<std::tuple<int, int, qpdf_offset_t>> found_objects;
-    std::vector<qpdf_offset_t> trailers;
-    int max_found = 0;
-
-    file->seek(0, SEEK_END);
-    qpdf_offset_t eof = file->tell();
-    file->seek(0, SEEK_SET);
-    // Don't allow very long tokens here during recovery. All the interesting tokens are covered.
-    static size_t const MAX_LEN = 10;
-    while (file->tell() < eof) {
-        QPDFTokenizer::Token t1 = read_token(MAX_LEN);
-        qpdf_offset_t token_start = file->tell() - toO(t1.getValue().length());
-        if (t1.isInteger()) {
-            auto pos = file->tell();
-            QPDFTokenizer::Token t2 = read_token(MAX_LEN);
-            if (t2.isInteger() && read_token(MAX_LEN).isWord("obj")) {
-                int obj = QUtil::string_to_int(t1.getValue().c_str());
-                int gen = QUtil::string_to_int(t2.getValue().c_str());
-                if (obj <= max_id_) {
-                    found_objects.emplace_back(obj, gen, token_start);
-                    if (obj > max_found) {
-                        max_found = obj;
-                    }
-                } else {
-                    warn_damaged("ignoring object with impossibly large id " + std::to_string(obj));
-                }
-            }
-            file->seek(pos, SEEK_SET);
-        } else if (!trailer_ && t1.isWord("trailer")) {
-            trailers.emplace_back(file->tell());
-        }
-        file->findAndSkipNextEOL();
-    }
-
-    table.resize(toS(max_found) + 1);
-
-    for (auto tr: trailers) {
-        file->seek(tr, SEEK_SET);
-        auto t = read_trailer();
-        if (!t.isDictionary()) {
-            // Oh well.  It was worth a try.
-        } else {
-            trailer_ = t;
-            break;
-        }
-        check_warnings();
-    }
-
-    auto rend = found_objects.rend();
-    for (auto it = found_objects.rbegin(); it != rend; it++) {
-        auto [obj, gen, token_start] = *it;
-        insert(obj, 1, token_start, gen);
-        check_warnings();
-    }
-
-    if (!trailer_) {
-        qpdf_offset_t max_offset{0};
-        // If there are any xref streams, take the last one to appear.
-        int i = -1;
-        for (auto const& item: table) {
-            ++i;
-            if (item.type() != 1) {
-                continue;
-            }
-            auto oh = objects.get(i, item.gen());
-            try {
-                if (!oh.isStreamOfType("/XRef")) {
-                    continue;
-                }
-            } catch (std::exception&) {
-                continue;
-            }
-            auto offset = item.offset();
-            if (offset > max_offset) {
-                max_offset = offset;
-                trailer_ = oh.getDict();
-            }
-            check_warnings();
-        }
-        if (max_offset > 0) {
-            try {
-                read(max_offset);
-            } catch (std::exception&) {
-                throw damaged_pdf(
-                    "error decoding candidate xref stream while recovering damaged file");
-            }
-            QTC::TC("qpdf", "QPDF recover xref stream");
-        }
-    }
-
-    if (!trailer_) {
-        // We could check the last encountered object to see if it was an xref stream.  If so, we
-        // could try to get the trailer from there.  This may make it possible to recover files with
-        // bad startxref pointers even when they have object streams.
-
-        throw damaged_pdf("unable to find trailer dictionary while recovering damaged file");
-    }
-    if (table.empty()) {
-        // We cannot check for an empty xref table in parse because empty tables are valid when
-        // creating QPDF objects from JSON.
-        throw damaged_pdf("unable to find objects while recovering damaged file");
-    }
-    check_warnings();
-    if (!initialized_) {
-        initialized_ = true;
-        qpdf.getAllPages();
-        check_warnings();
-        if (qpdf.m->all_pages.empty()) {
-            initialized_ = false;
-            throw damaged_pdf("unable to find any pages while recovering damaged file");
-        }
-    }
-    // We could iterate through the objects looking for streams and try to find objects inside of
-    // them, but it's probably not worth the trouble.  Acrobat can't recover files with any errors
-    // in an xref stream, and this would be a real long shot anyway.  If we wanted to do anything
-    // that involved looking at stream contents, we'd also have to call initializeEncryption() here.
-    // It's safe to call it more than once.
-}
-
-void
-Xref_table::read(qpdf_offset_t xref_offset)
-{
-    std::map<int, int> free_table;
-    std::set<qpdf_offset_t> visited;
-    while (xref_offset) {
-        visited.insert(xref_offset);
-        char buf[7];
-        memset(buf, 0, sizeof(buf));
-        file->seek(xref_offset, SEEK_SET);
-        // Some files miss the mark a little with startxref. We could do a better job of searching
-        // in the neighborhood for something that looks like either an xref table or stream, but the
-        // simple heuristic of skipping whitespace can help with the xref table case and is harmless
-        // with the stream case.
-        bool done = false;
-        bool skipped_space = false;
-        while (!done) {
-            char ch;
-            if (1 == file->read(&ch, 1)) {
-                if (QUtil::is_space(ch)) {
-                    skipped_space = true;
-                } else {
-                    file->unreadCh(ch);
-                    done = true;
-                }
-            } else {
-                QTC::TC("qpdf", "QPDF eof skipping spaces before xref", skipped_space ? 0 : 1);
-                done = true;
-            }
-        }
-
-        file->read(buf, sizeof(buf) - 1);
-        // The PDF spec says xref must be followed by a line terminator, but files exist in the wild
-        // where it is terminated by arbitrary whitespace.
-        if ((strncmp(buf, "xref", 4) == 0) && QUtil::is_space(buf[4])) {
-            if (skipped_space) {
-                QTC::TC("qpdf", "QPDF xref skipped space");
-                warn_damaged("extraneous whitespace seen before xref");
-            }
-            QTC::TC(
-                "qpdf",
-                "QPDF xref space",
-                ((buf[4] == '\n')       ? 0
-                     : (buf[4] == '\r') ? 1
-                     : (buf[4] == ' ')  ? 2
-                                        : 9999));
-            int skip = 4;
-            // buf is null-terminated, and QUtil::is_space('\0') is false, so this won't overrun.
-            while (QUtil::is_space(buf[skip])) {
-                ++skip;
-            }
-            xref_offset = process_section(xref_offset + skip);
-        } else {
-            xref_offset = read_stream(xref_offset);
-        }
-        if (visited.count(xref_offset) != 0) {
-            QTC::TC("qpdf", "QPDF xref loop");
-            throw damaged_pdf("loop detected following xref tables");
-        }
-    }
-
-    if (!trailer_) {
-        throw damaged_pdf("unable to find trailer while reading xref");
-    }
-    int size = trailer_.getKey("/Size").getIntValueAsInt();
-
-    if (size < 3) {
-        throw damaged_pdf("too few objects - file can't have a page tree");
-    }
-
-    // We are no longer reporting what the highest id in the xref table is. I don't think it adds
-    // anything. If we want to report more detail, we should report the total number of missing
-    // entries, including missing entries before the last actual entry.
-}
-
-Xref_table::Subsection
-Xref_table::subsection(std::string const& line)
-{
-    auto terminate = [this]() -> void {
-        QTC::TC("qpdf", "QPDF invalid xref");
-        throw damaged_table("xref syntax invalid");
-    };
-
-    // is_space and is_digit both return false on '\0', so this will not overrun the null-terminated
-    // buffer.
-    char const* p = line.c_str();
-    char const* start = line.c_str();
-
-    // Skip zero or more spaces
-    while (QUtil::is_space(*p)) {
-        ++p;
-    }
-    // Require digit
-    if (!QUtil::is_digit(*p)) {
-        terminate();
-    }
-    // Gather digits
-    std::string obj_str;
-    while (QUtil::is_digit(*p)) {
-        obj_str.append(1, *p++);
-    }
-    // Require space
-    if (!QUtil::is_space(*p)) {
-        terminate();
-    }
-    // Skip spaces
-    while (QUtil::is_space(*p)) {
-        ++p;
-    }
-    // Require digit
-    if (!QUtil::is_digit(*p)) {
-        terminate();
-    }
-    // Gather digits
-    std::string num_str;
-    while (QUtil::is_digit(*p)) {
-        num_str.append(1, *p++);
-    }
-    // Skip any space including line terminators
-    while (QUtil::is_space(*p)) {
-        ++p;
-    }
-    auto obj = QUtil::string_to_int(obj_str.c_str());
-    auto count = QUtil::string_to_int(num_str.c_str());
-    if (obj > max_id() || count > max_id() || (obj + count) > max_id()) {
-        throw damaged_table("xref table subsection header contains impossibly large entry");
-    }
-    return {obj, count, file->getLastOffset() + toI(p - start)};
-}
-
-std::vector<Xref_table::Subsection>
-Xref_table::bad_subsections(std::string& line, qpdf_offset_t start)
-{
-    std::vector<Xref_table::Subsection> result;
-    file->seek(start, SEEK_SET);
-
-    while (true) {
-        line.assign(50, '\0');
-        file->read(line.data(), line.size());
-        auto [obj, num, offset] = result.emplace_back(subsection(line));
-        file->seek(offset, SEEK_SET);
-        for (qpdf_offset_t i = obj; i - num < obj; ++i) {
-            if (!std::get<0>(read_entry())) {
-                QTC::TC("qpdf", "QPDF invalid xref entry");
-                throw damaged_table("invalid xref entry (obj=" + std::to_string(i) + ")");
-            }
-        }
-        qpdf_offset_t pos = file->tell();
-        if (read_token().isWord("trailer")) {
-            return result;
-        } else {
-            file->seek(pos, SEEK_SET);
-        }
-    }
-}
-
-// Optimistically read and parse all subsection headers. If an error is encountered return the
-// result of bad_subsections.
-std::vector<Xref_table::Subsection>
-Xref_table::subsections(std::string& line)
-{
-    auto recovery_offset = file->tell();
-    try {
-        std::vector<Xref_table::Subsection> result;
-
-        while (true) {
-            line.assign(50, '\0');
-            file->read(line.data(), line.size());
-            auto& sub = result.emplace_back(subsection(line));
-            auto count = std::get<1>(sub);
-            auto offset = std::get<2>(sub);
-            file->seek(offset + 20 * toO(count) - 1, SEEK_SET);
-            file->read(line.data(), 1);
-            if (!(line[0] == '\n' || line[0] == '\n')) {
-                return bad_subsections(line, recovery_offset);
-            }
-            qpdf_offset_t pos = file->tell();
-            if (read_token().isWord("trailer")) {
-                return result;
-            } else {
-                file->seek(pos, SEEK_SET);
-            }
-        }
-    } catch (...) {
-        return bad_subsections(line, recovery_offset);
-    }
-}
-
-// Returns (success, f1, f2, type).
-std::tuple<bool, qpdf_offset_t, int, char>
-Xref_table::read_bad_entry()
-{
-    qpdf_offset_t f1{0};
-    int f2{0};
-    char type{'\0'};
-    // Reposition after initial read attempt and reread.
-    file->seek(file->getLastOffset(), SEEK_SET);
-    auto line = file->readLine(30);
-
-    // is_space and is_digit both return false on '\0', so this will not overrun the null-terminated
-    // buffer.
-    char const* p = line.data();
-
-    // Skip zero or more spaces. There aren't supposed to be any.
-    bool invalid = false;
-    while (QUtil::is_space(*p)) {
-        ++p;
-        QTC::TC("qpdf", "QPDF ignore first space in xref entry");
-        invalid = true;
-    }
-    // Require digit
-    if (!QUtil::is_digit(*p)) {
-        return {false, 0, 0, '\0'};
-    }
-    // Gather digits
-    std::string f1_str;
-    while (QUtil::is_digit(*p)) {
-        f1_str.append(1, *p++);
-    }
-    // Require space
-    if (!QUtil::is_space(*p)) {
-        return {false, 0, 0, '\0'};
-    }
-    if (QUtil::is_space(*(p + 1))) {
-        QTC::TC("qpdf", "QPDF ignore first extra space in xref entry");
-        invalid = true;
-    }
-    // Skip spaces
-    while (QUtil::is_space(*p)) {
-        ++p;
-    }
-    // Require digit
-    if (!QUtil::is_digit(*p)) {
-        return {false, 0, 0, '\0'};
-    }
-    // Gather digits
-    std::string f2_str;
-    while (QUtil::is_digit(*p)) {
-        f2_str.append(1, *p++);
-    }
-    // Require space
-    if (!QUtil::is_space(*p)) {
-        return {false, 0, 0, '\0'};
-    }
-    if (QUtil::is_space(*(p + 1))) {
-        QTC::TC("qpdf", "QPDF ignore second extra space in xref entry");
-        invalid = true;
-    }
-    // Skip spaces
-    while (QUtil::is_space(*p)) {
-        ++p;
-    }
-    if ((*p == 'f') || (*p == 'n')) {
-        type = *p;
-    } else {
-        return {false, 0, 0, '\0'};
-    }
-    if ((f1_str.length() != 10) || (f2_str.length() != 5)) {
-        QTC::TC("qpdf", "QPDF ignore length error xref entry");
-        invalid = true;
-    }
-
-    if (invalid) {
-        qpdf.warn(damaged_table("accepting invalid xref table entry"));
-    }
-
-    f1 = QUtil::string_to_ll(f1_str.c_str());
-    f2 = QUtil::string_to_int(f2_str.c_str());
-
-    return {true, f1, f2, type};
-}
-
-// Optimistically read and parse xref entry. If entry is bad, call read_bad_xrefEntry and return
-// result. Returns (success, f1, f2, type).
-std::tuple<bool, qpdf_offset_t, int, char>
-Xref_table::read_entry()
-{
-    qpdf_offset_t f1{0};
-    int f2{0};
-    char type{'\0'};
-    std::array<char, 21> line;
-    f1 = 0;
-    f2 = 0;
-    if (file->read(line.data(), 20) != 20) {
-        // C++20: [[unlikely]]
-        return {false, 0, 0, '\0'};
-    }
-    line[20] = '\0';
-    char const* p = line.data();
-
-    int f1_len = 0;
-    int f2_len = 0;
-
-    // is_space and is_digit both return false on '\0', so this will not overrun the null-terminated
-    // buffer.
-
-    // Gather f1 digits. NB No risk of overflow as 9'999'999'999 < max long long.
-    while (*p == '0') {
-        ++f1_len;
-        ++p;
-    }
-    while (QUtil::is_digit(*p) && f1_len++ < 10) {
-        f1 *= 10;
-        f1 += *p++ - '0';
-    }
-    // Require space
-    if (!QUtil::is_space(*p++)) {
-        // Entry doesn't start with space or digit.
-        // C++20: [[unlikely]]
-        return {false, 0, 0, '\0'};
-    }
-    // Gather digits. NB No risk of overflow as 99'999 < max int.
-    while (*p == '0') {
-        ++f2_len;
-        ++p;
-    }
-    while (QUtil::is_digit(*p) && f2_len++ < 5) {
-        f2 *= 10;
-        f2 += static_cast<int>(*p++ - '0');
-    }
-    if (QUtil::is_space(*p++) && (*p == 'f' || *p == 'n')) {
-        // C++20: [[likely]]
-        type = *p;
-        // No test for valid line[19].
-        if (*(++p) && *(++p) && (*p == '\n' || *p == '\r') && f1_len == 10 && f2_len == 5) {
-            // C++20: [[likely]]
-            return {true, f1, f2, type};
-        }
-    }
-    return read_bad_entry();
-}
-
-// Read a single cross-reference table section and associated trailer.
-qpdf_offset_t
-Xref_table::process_section(qpdf_offset_t xref_offset)
-{
-    file->seek(xref_offset, SEEK_SET);
-    std::string line;
-    auto subs = subsections(line);
-
-    auto cur_trailer_offset = file->tell();
-    auto cur_trailer = read_trailer();
-    if (!cur_trailer.isDictionary()) {
-        QTC::TC("qpdf", "QPDF missing trailer");
-        throw qpdf.damagedPDF("", "expected trailer dictionary");
-    }
-
-    if (!trailer_) {
-        unsigned int sz;
-        trailer_ = cur_trailer;
-
-        if (!trailer_.hasKey("/Size")) {
-            QTC::TC("qpdf", "QPDF trailer lacks size");
-            throw qpdf.damagedPDF("trailer", "trailer dictionary lacks /Size key");
-        }
-        if (!trailer_.getKey("/Size").getValueAsUInt(sz)) {
-            QTC::TC("qpdf", "QPDF trailer size not integer");
-            throw qpdf.damagedPDF("trailer", "/Size key in trailer dictionary is not an integer");
-        }
-        if (sz >= static_cast<unsigned int>(max_id_)) {
-            QTC::TC("qpdf", "QPDF trailer size impossibly large");
-            throw qpdf.damagedPDF("trailer", "/Size key in trailer dictionary is impossibly large");
-        }
-        table.resize(sz);
-    }
-
-    for (auto [obj, num, offset]: subs) {
-        file->seek(offset, SEEK_SET);
-        for (qpdf_offset_t i = obj; i - num < obj; ++i) {
-            if (i == 0) {
-                // This is needed by checkLinearization()
-                first_item_offset_ = file->tell();
-            }
-            // For xref_table, these will always be small enough to be ints
-            auto [success, f1, f2, type] = read_entry();
-            if (!success) {
-                throw damaged_table("invalid xref entry (obj=" + std::to_string(i) + ")");
-            }
-            if (type == 'f') {
-                insert_free(QPDFObjGen(toI(i), f2));
-            } else {
-                insert(toI(i), 1, f1, f2);
-            }
-        }
-        qpdf_offset_t pos = file->tell();
-        if (read_token().isWord("trailer")) {
-            break;
-        } else {
-            file->seek(pos, SEEK_SET);
-        }
-    }
-
-    if (cur_trailer.hasKey("/XRefStm")) {
-        if (ignore_streams_) {
-            QTC::TC("qpdf", "QPDF ignoring XRefStm in trailer");
-        } else {
-            if (cur_trailer.getKey("/XRefStm").isInteger()) {
-                // Read the xref stream but disregard any return value -- we'll use our trailer's
-                // /Prev key instead of the xref stream's.
-                (void)read_stream(cur_trailer.getKey("/XRefStm").getIntValue());
-            } else {
-                throw qpdf.damagedPDF("xref stream", cur_trailer_offset, "invalid /XRefStm");
-            }
-        }
-    }
-
-    if (cur_trailer.hasKey("/Prev")) {
-        if (!cur_trailer.getKey("/Prev").isInteger()) {
-            QTC::TC("qpdf", "QPDF trailer prev not integer");
-            throw qpdf.damagedPDF(
-                "trailer", cur_trailer_offset, "/Prev key in trailer dictionary is not an integer");
-        }
-        QTC::TC("qpdf", "QPDF prev key in trailer dictionary");
-        return cur_trailer.getKey("/Prev").getIntValue();
-    }
-
-    return 0;
-}
-
-// Read a single cross-reference stream.
-qpdf_offset_t
-Xref_table::read_stream(qpdf_offset_t xref_offset)
-{
-    if (!ignore_streams_) {
-        QPDFObjGen x_og;
-        QPDFObjectHandle xref_obj;
-        try {
-            xref_obj =
-                objects.read(false, xref_offset, "xref stream", QPDFObjGen(0, 0), x_og, true);
-        } catch (QPDFExc&) {
-            // ignore -- report error below
-        }
-        if (xref_obj.isStreamOfType("/XRef")) {
-            QTC::TC("qpdf", "QPDF found xref stream");
-            return process_stream(xref_offset, xref_obj);
-        }
-    }
-
-    QTC::TC("qpdf", "QPDF can't find xref");
-    throw qpdf.damagedPDF("", xref_offset, "xref not found");
-    return 0; // unreachable
-}
-
-// Return the entry size of the xref stream and the processed W array.
-std::pair<int, std::array<int, 3>>
-Xref_table::process_W(QPDFObjectHandle& dict, std::function<QPDFExc(std::string_view)> damaged)
-{
-    auto W_obj = dict.getKey("/W");
-    if (!(W_obj.isArray() && W_obj.getArrayNItems() >= 3 && W_obj.getArrayItem(0).isInteger() &&
-          W_obj.getArrayItem(1).isInteger() && W_obj.getArrayItem(2).isInteger())) {
-        throw damaged("Cross-reference stream does not have a proper /W key");
-    }
-
-    std::array<int, 3> W;
-    int entry_size = 0;
-    auto w_vector = W_obj.getArrayAsVector();
-    int max_bytes = sizeof(qpdf_offset_t);
-    for (size_t i = 0; i < 3; ++i) {
-        W[i] = w_vector[i].getIntValueAsInt();
-        if (W[i] > max_bytes) {
-            throw damaged("Cross-reference stream's /W contains impossibly large values");
-        }
-        if (W[i] < 0) {
-            throw damaged("Cross-reference stream's /W contains negative values");
-        }
-        entry_size += W[i];
-    }
-    if (entry_size == 0) {
-        throw damaged("Cross-reference stream's /W indicates entry size of 0");
-    }
-    return {entry_size, W};
-}
-
-// Validate Size entry and return the maximum number of entries that the xref stream can contain and
-// the value of the Size entry.
-std::pair<int, size_t>
-Xref_table::process_Size(
-    QPDFObjectHandle& dict, int entry_size, std::function<QPDFExc(std::string_view)> damaged)
-{
-    // Number of entries is limited by the highest possible object id and stream size.
-    auto max_num_entries = std::numeric_limits<int>::max();
-    if (max_num_entries > (std::numeric_limits<qpdf_offset_t>::max() / entry_size)) {
-        max_num_entries = toI(std::numeric_limits<qpdf_offset_t>::max() / entry_size);
-    }
-
-    auto Size_obj = dict.getKey("/Size");
-    long long size;
-    if (!dict.getKey("/Size").getValueAsInt(size)) {
-        throw damaged("Cross-reference stream does not have a proper /Size key");
-    } else if (size < 0) {
-        throw damaged("Cross-reference stream has a negative /Size key");
-    } else if (size >= max_num_entries) {
-        throw damaged("Cross-reference stream has an impossibly large /Size key");
-    }
-    // We are not validating that Size <= (Size key of parent xref / trailer).
-    return {max_num_entries, toS(size)};
-}
-
-// Return the number of entries of the xref stream and the processed Index array.
-std::pair<int, std::vector<std::pair<int, int>>>
-Xref_table::process_Index(
-    QPDFObjectHandle& dict, int max_num_entries, std::function<QPDFExc(std::string_view)> damaged)
-{
-    auto size = dict.getKey("/Size").getIntValueAsInt();
-    auto Index_obj = dict.getKey("/Index");
-
-    if (Index_obj.isArray()) {
-        std::vector<std::pair<int, int>> indx;
-        int num_entries = 0;
-        auto index_vec = Index_obj.getArrayAsVector();
-        if ((index_vec.size() % 2) || index_vec.size() < 2) {
-            throw damaged("Cross-reference stream's /Index has an invalid number of values");
-        }
-
-        int i = 0;
-        long long first = 0;
-        for (auto& val: index_vec) {
-            if (val.isInteger()) {
-                if (i % 2) {
-                    auto count = val.getIntValue();
-                    if (count <= 0) {
-                        throw damaged(
-                            "Cross-reference stream section claims to contain " +
-                            std::to_string(count) + " entries");
-                    }
-                    // We are guarding against the possibility of num_entries * entry_size
-                    // overflowing. We are not checking that entries are in ascending order as
-                    // required by the spec, which probably should generate a warning. We are also
-                    // not checking that for each subsection first object number + number of entries
-                    // <= /Size. The spec requires us to ignore object number > /Size.
-                    if (first > (max_num_entries - count) ||
-                        count > (max_num_entries - num_entries)) {
-                        throw damaged(
-                            "Cross-reference stream claims to contain too many entries: " +
-                            std::to_string(first) + " " + std::to_string(max_num_entries) + " " +
-                            std::to_string(num_entries));
-                    }
-                    indx.emplace_back(static_cast<int>(first), static_cast<int>(count));
-                    num_entries += static_cast<int>(count);
-                } else {
-                    first = val.getIntValue();
-                    if (first < 0) {
-                        throw damaged(
-                            "Cross-reference stream's /Index contains a negative object id");
-                    } else if (first > max_num_entries) {
-                        throw damaged("Cross-reference stream's /Index contains an impossibly "
-                                      "large object id");
-                    }
-                }
-            } else {
-                throw damaged(
-                    "Cross-reference stream's /Index's item " + std::to_string(i) +
-                    " is not an integer");
-            }
-            i++;
-        }
-        QTC::TC("qpdf", "QPDF xref /Index is array", index_vec.size() == 2 ? 0 : 1);
-        return {num_entries, indx};
-    } else if (Index_obj.isNull()) {
-        QTC::TC("qpdf", "QPDF xref /Index is null");
-        return {size, {{0, size}}};
-    } else {
-        throw damaged("Cross-reference stream does not have a proper /Index key");
-    }
-}
-
-qpdf_offset_t
-Xref_table::process_stream(qpdf_offset_t xref_offset, QPDFObjectHandle& xref_obj)
-{
-    auto damaged = [this, xref_offset](std::string_view msg) -> QPDFExc {
-        return qpdf.damagedPDF("xref stream", xref_offset, msg.data());
-    };
-
-    auto dict = xref_obj.getDict();
-
-    auto [entry_size, W] = process_W(dict, damaged);
-    auto [max_num_entries, size] = process_Size(dict, entry_size, damaged);
-    auto [num_entries, indx] = process_Index(dict, max_num_entries, damaged);
-
-    std::shared_ptr<Buffer> bp = xref_obj.getStreamData(qpdf_dl_specialized);
-    size_t actual_size = bp->getSize();
-    auto expected_size = toS(entry_size) * toS(num_entries);
-
-    if (expected_size != actual_size) {
-        QPDFExc x = damaged(
-            "Cross-reference stream data has the wrong size; expected = " +
-            std::to_string(expected_size) + "; actual = " + std::to_string(actual_size));
-        if (expected_size > actual_size) {
-            throw x;
-        } else {
-            qpdf.warn(x);
-        }
-    }
-
-    if (!trailer_) {
-        trailer_ = dict;
-        if (size > toS(max_id_)) {
-            throw damaged("Cross-reference stream /Size entry is impossibly large");
-        }
-        table.resize(size);
-    }
-
-    bool saw_first_compressed_object = false;
-
-    // Actual size vs. expected size check above ensures that we will not overflow any buffers here.
-    // We know that entry_size * num_entries is less or equal to the size of the buffer.
-    auto p = bp->getBuffer();
-    for (auto [obj, sec_entries]: indx) {
-        // Process a subsection.
-        for (int i = 0; i < sec_entries; ++i) {
-            // Read this entry
-            std::array<qpdf_offset_t, 3> fields{};
-            if (W[0] == 0) {
-                QTC::TC("qpdf", "QPDF default for xref stream field 0");
-                fields[0] = 1;
-            }
-            for (size_t j = 0; j < 3; ++j) {
-                for (int k = 0; k < W[j]; ++k) {
-                    fields[j] <<= 8;
-                    fields[j] |= *p++;
-                }
-            }
-
-            // Get the generation number.  The generation number is 0 unless this is an uncompressed
-            // object record, in which case the generation number appears as the third field.
-            if (saw_first_compressed_object) {
-                if (fields[0] != 2) {
-                    uncompressed_after_compressed_ = true;
-                }
-            } else if (fields[0] == 2) {
-                saw_first_compressed_object = true;
-            }
-            if (obj == 0) {
-                // This is needed by checkLinearization()
-                first_item_offset_ = xref_offset;
-            } else if (fields[0] == 0) {
-                // Ignore fields[2], which we don't care about in this case. This works around the
-                // issue of some PDF files that put invalid values, like -1, here for deleted
-                // objects.
-                insert_free(QPDFObjGen(obj, 0));
-            } else {
-                insert(obj, toI(fields[0]), fields[1], toI(fields[2]));
-            }
-            ++obj;
-        }
-    }
-
-    if (dict.hasKey("/Prev")) {
-        if (!dict.getKey("/Prev").isInteger()) {
-            throw qpdf.damagedPDF(
-                "xref stream", "/Prev key in xref stream dictionary is not an integer");
-        }
-        QTC::TC("qpdf", "QPDF prev key in xref stream dictionary");
-        return dict.getKey("/Prev").getIntValue();
-    } else {
-        return 0;
-    }
-}
-
-void
-Xref_table::insert(int obj, int f0, qpdf_offset_t f1, int f2)
-{
-    // Populate the xref table in such a way that the first reference to an object that we see,
-    // which is the one in the latest xref table in which it appears, is the one that gets stored.
-    // This works because we are reading more recent appends before older ones.
-
-    // If there is already an entry for this object and generation in the table, it means that a
-    // later xref table has registered this object.  Disregard this one.
-
-    int new_gen = f0 == 2 ? 0 : f2;
-
-    if (!(obj > 0 && static_cast<size_t>(obj) < table.size() && 0 <= f2 && new_gen < 65535)) {
-        // We are ignoring invalid objgens. Most will arrive here from xref reconstruction. There
-        // is probably no point having another warning but we could count invalid items in order to
-        // decide when to give up.
-        QTC::TC("qpdf", "QPDF xref overwrite invalid objgen");
-        return;
-    }
-
-    auto& entry = table[static_cast<size_t>(obj)];
-    auto old_type = entry.type();
-
-    if (!old_type && entry.gen() > 0) {
-        // At the moment we are processing the updates last to first and therefore the gen doesn't
-        // matter as long as it > 0 to distinguish it from an uninitialized entry. This will need
-        // to be revisited when we want to support incremental updates or more comprehensive
-        // checking.
-        QTC::TC("qpdf", "QPDF xref deleted object");
-        return;
-    }
-
-    if (f0 == 2 && static_cast<int>(f1) == obj) {
-        qpdf.warn(qpdf.damagedPDF(
-            "xref stream", "self-referential object stream " + std::to_string(obj)));
-        return;
-    }
-
-    if (old_type && entry.gen() >= new_gen) {
-        QTC::TC("qpdf", "QPDF xref reused object");
-        return;
-    }
-
-    switch (f0) {
-    case 1:
-        // f2 is generation
-        QTC::TC("qpdf", "QPDF xref gen > 0", (f2 > 0) ? 1 : 0);
-        entry = {f2, Uncompressed(f1)};
-        break;
-
-    case 2:
-        entry = {0, Compressed(toI(f1), f2)};
-        object_streams_ = true;
-        break;
-
-    default:
-        throw qpdf.damagedPDF(
-            "xref stream", "unknown xref stream entry type " + std::to_string(f0));
-        break;
-    }
-}
-
-void
-Xref_table::insert_free(QPDFObjGen og)
-{
-    // At the moment we are processing the updates last to first and therefore the gen doesn't
-    // matter as long as it > 0 to distinguish it from an uninitialized entry. This will need to be
-    // revisited when we want to support incremental updates or more comprehensive checking.
-    if (og.getObj() < 1) {
-        return;
-    }
-    size_t id = static_cast<size_t>(og.getObj());
-    if (id < table.size() && !type(id)) {
-        table[id] = {1, {}};
-    }
-}
-
-QPDFObjGen
-Xref_table::at_offset(qpdf_offset_t offset) const noexcept
-{
-    int id = 0;
-    int gen = 0;
-    qpdf_offset_t start = 0;
-
-    int i = 0;
-    for (auto const& item: table) {
-        auto o = item.offset();
-        if (start < o && o <= offset) {
-            start = o;
-            id = i;
-            gen = item.gen();
-        }
-        ++i;
-    }
-    return QPDFObjGen(id, gen);
-}
-
-std::map<QPDFObjGen, QPDFXRefEntry>
-Xref_table::as_map() const
-{
-    std::map<QPDFObjGen, QPDFXRefEntry> result;
-    int i{0};
-    for (auto const& item: table) {
-        switch (item.type()) {
-        case 0:
-            break;
-        case 1:
-            result.emplace(QPDFObjGen(i, item.gen()), item.offset());
-            break;
-        case 2:
-            result.emplace(
-                QPDFObjGen(i, 0), QPDFXRefEntry(item.stream_number(), item.stream_index()));
-            break;
-        default:
-            throw std::logic_error("Xref_table: invalid entry type");
-        }
-        ++i;
-    }
-    return result;
-}
-
-void
-Xref_table::show()
-{
-    auto& cout = *qpdf.m->log->getInfo();
-    int i = -1;
-    for (auto const& item: table) {
-        ++i;
-        if (item.type()) {
-            cout << std::to_string(i) << "/" << std::to_string(item.gen()) << ": ";
-            switch (item.type()) {
-            case 1:
-                cout << "uncompressed; offset = " << item.offset() << "\n";
-                break;
-
-            case 2:
-                cout << "compressed; stream = " << item.stream_number()
-                     << ", index = " << item.stream_index() << "\n";
-                break;
-
-            default:
-                throw std::logic_error(
-                    "unknown cross-reference table type while showing xref_table");
-            }
-        }
-    }
-}
-
-// Resolve all objects in the xref table. If this triggers a xref table reconstruction abort and
-// return false. Otherwise return true.
-bool
-Xref_table::resolve()
-{
-    bool may_change = !reconstructed_;
-    int i = -1;
-    for (auto& item: table) {
-        ++i;
-        if (item.type()) {
-            if (objects.unresolved(QPDFObjGen(i, item.gen()))) {
-                objects.resolve(QPDFObjGen(i, item.gen()));
-                if (may_change && reconstructed_) {
-                    return false;
-                }
-            }
-        }
-    }
-    return true;
-}
-
-std::vector<QPDFObjectHandle>
-Objects ::all()
-{
-    // After fixDanglingReferences is called, all objects are in the object cache.
-    qpdf.fixDanglingReferences();
-    std::vector<QPDFObjectHandle> result;
-    for (auto const& iter: table) {
-        result.emplace_back(iter.second.object);
-    }
-    return result;
-}
-
-QPDFObjectHandle
-Xref_table::read_trailer()
-{
-    qpdf_offset_t offset = file->tell();
-    bool empty = false;
-    auto object = QPDFParser(*file, "trailer", tokenizer, nullptr, &qpdf, true).parse(empty, false);
-    if (empty) {
-        // Nothing in the PDF spec appears to allow empty objects, but they have been encountered in
-        // actual PDF files and Adobe Reader appears to ignore them.
-        qpdf.warn(qpdf.damagedPDF("trailer", "empty object treated as null"));
-    } else if (object.isDictionary() && read_token().isWord("stream")) {
-        qpdf.warn(qpdf.damagedPDF("trailer", file->tell(), "stream keyword found in trailer"));
-    }
-    // Override last_offset so that it points to the beginning of the object we just read
-    file->setLastOffset(offset);
-    return object;
-}
-
-QPDFObjectHandle
-Objects::read_object(std::string const& description, QPDFObjGen og)
-{
-    qpdf.setLastObjectDescription(description, og);
-    qpdf_offset_t offset = m->file->tell();
-    bool empty = false;
-
-    StringDecrypter decrypter{&qpdf, og};
-    StringDecrypter* decrypter_ptr = m->encp->encrypted ? &decrypter : nullptr;
-    auto object =
-        QPDFParser(*m->file, m->last_object_description, m->tokenizer, decrypter_ptr, &qpdf, true)
-            .parse(empty, false);
-    if (empty) {
-        // Nothing in the PDF spec appears to allow empty objects, but they have been encountered in
-        // actual PDF files and Adobe Reader appears to ignore them.
-        qpdf.warn(
-            qpdf.damagedPDF(*m->file, m->file->getLastOffset(), "empty object treated as null"));
-        return object;
-    }
-    auto token = qpdf.readToken(*m->file);
-    if (object.isDictionary() && token.isWord("stream")) {
-        read_stream(object, og, offset);
-        token = qpdf.readToken(*m->file);
-    }
-    if (!token.isWord("endobj")) {
-        QTC::TC("qpdf", "QPDF err expected endobj");
-        qpdf.warn(qpdf.damagedPDF("expected endobj"));
-    }
-    return object;
-}
-
-// After reading stream dictionary and stream keyword, read rest of stream.
-void
-Objects::read_stream(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset)
-{
-    validate_stream_line_end(object, og, offset);
-
-    // Must get offset before accessing any additional objects since resolving a previously
-    // unresolved indirect object will change file position.
-    qpdf_offset_t stream_offset = m->file->tell();
-    size_t length = 0;
-
-    try {
-        auto length_obj = object.getKey("/Length");
-
-        if (!length_obj.isInteger()) {
-            if (length_obj.isNull()) {
-                QTC::TC("qpdf", "QPDF stream without length");
-                throw qpdf.damagedPDF(offset, "stream dictionary lacks /Length key");
-            }
-            QTC::TC("qpdf", "QPDF stream length not integer");
-            throw qpdf.damagedPDF(offset, "/Length key in stream dictionary is not an integer");
-        }
-
-        length = toS(length_obj.getUIntValue());
-        // Seek in two steps to avoid potential integer overflow
-        m->file->seek(stream_offset, SEEK_SET);
-        m->file->seek(toO(length), SEEK_CUR);
-        if (!qpdf.readToken(*m->file).isWord("endstream")) {
-            QTC::TC("qpdf", "QPDF missing endstream");
-            throw qpdf.damagedPDF("expected endstream");
-        }
-    } catch (QPDFExc& e) {
-        if (m->attempt_recovery) {
-            qpdf.warn(e);
-            length = recover_stream_length(m->file_sp, og, stream_offset);
-        } else {
-            throw;
-        }
-    }
-    object = {QPDF_Stream::create(&qpdf, og, object, stream_offset, length)};
-}
-
-void
-Objects::validate_stream_line_end(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset)
-{
-    // The PDF specification states that the word "stream" should be followed by either a carriage
-    // return and a newline or by a newline alone.  It specifically disallowed following it by a
-    // carriage return alone since, in that case, there would be no way to tell whether the NL in a
-    // CR NL sequence was part of the stream data.  However, some readers, including Adobe reader,
-    // accept a carriage return by itself when followed by a non-newline character, so that's what
-    // we do here. We have also seen files that have extraneous whitespace between the stream
-    // keyword and the newline.
-    while (true) {
-        char ch;
-        if (m->file->read(&ch, 1) == 0) {
-            // A premature EOF here will result in some other problem that will get reported at
-            // another time.
-            return;
-        }
-        if (ch == '\n') {
-            // ready to read stream data
-            QTC::TC("qpdf", "QPDF stream with NL only");
-            return;
-        }
-        if (ch == '\r') {
-            // Read another character
-            if (m->file->read(&ch, 1) != 0) {
-                if (ch == '\n') {
-                    // Ready to read stream data
-                    QTC::TC("qpdf", "QPDF stream with CRNL");
-                } else {
-                    // Treat the \r by itself as the whitespace after endstream and start reading
-                    // stream data in spite of not having seen a newline.
-                    QTC::TC("qpdf", "QPDF stream with CR only");
-                    m->file->unreadCh(ch);
-                    qpdf.warn(qpdf.damagedPDF(
-                        m->file->tell(), "stream keyword followed by carriage return only"));
-                }
-            }
-            return;
-        }
-        if (!QUtil::is_space(ch)) {
-            QTC::TC("qpdf", "QPDF stream without newline");
-            m->file->unreadCh(ch);
-            qpdf.warn(qpdf.damagedPDF(
-                m->file->tell(), "stream keyword not followed by proper line terminator"));
-            return;
-        }
-        qpdf.warn(
-            qpdf.damagedPDF(m->file->tell(), "stream keyword followed by extraneous whitespace"));
-    }
-}
-
-QPDFObjectHandle
-Objects::readObjectInStream(std::shared_ptr<InputSource>& input, int obj)
-{
-    m->last_object_description.erase(7); // last_object_description starts with "object "
-    m->last_object_description += std::to_string(obj);
-    m->last_object_description += " 0";
-
-    bool empty = false;
-    auto object = QPDFParser(*input, m->last_object_description, m->tokenizer, nullptr, &qpdf, true)
-                      .parse(empty, false);
-    if (empty) {
-        // Nothing in the PDF spec appears to allow empty objects, but they have been encountered in
-        // actual PDF files and Adobe Reader appears to ignore them.
-        qpdf.warn(qpdf.damagedPDF(*input, input->getLastOffset(), "empty object treated as null"));
-    }
-    return object;
-}
-
-bool
-QPDF::findEndstream()
-{
-    // Find endstream or endobj. Position the input at that token.
-    auto t = readToken(*m->file, 20);
-    if (t.isWord("endobj") || t.isWord("endstream")) {
-        m->file->seek(m->file->getLastOffset(), SEEK_SET);
-        return true;
-    }
-    return false;
-}
-
-size_t
-Objects::recover_stream_length(
-    std::shared_ptr<InputSource> input, QPDFObjGen og, qpdf_offset_t stream_offset)
-{
-    // Try to reconstruct stream length by looking for endstream or endobj
-    qpdf.warn(qpdf.damagedPDF(*input, stream_offset, "attempting to recover stream length"));
-
-    PatternFinder ef(qpdf, &QPDF::findEndstream);
-    size_t length = 0;
-    if (m->file->findFirst("end", stream_offset, 0, ef)) {
-        length = toS(m->file->tell() - stream_offset);
-        // Reread endstream but, if it was endobj, don't skip that.
-        QPDFTokenizer::Token t = qpdf.readToken(*m->file);
-        if (t.getValue() == "endobj") {
-            m->file->seek(m->file->getLastOffset(), SEEK_SET);
-        }
-    }
-
-    if (length) {
-        // Make sure this is inside this object
-        auto found = xref.at_offset(stream_offset + toO(length));
-        if (found == QPDFObjGen() || found == og) {
-            // If we are trying to recover an XRef stream the xref table will not contain and
-            // won't contain any entries, therefore we cannot check the found length. Otherwise we
-            // found endstream\endobj within the space allowed for this object, so we're probably
-            // in good shape.
-        } else {
-            QTC::TC("qpdf", "QPDF found wrong endstream in recovery");
-            length = 0;
-        }
-    }
-
-    if (length == 0) {
-        qpdf.warn(qpdf.damagedPDF(
-            *input, stream_offset, "unable to recover stream data; treating stream as empty"));
-    } else {
-        qpdf.warn(qpdf.damagedPDF(
-            *input, stream_offset, "recovered stream length: " + std::to_string(length)));
-    }
-
-    QTC::TC("qpdf", "QPDF recovered stream length");
-    return length;
-}
-
-QPDFObjectHandle
-Objects::read(
-    bool try_recovery,
-    qpdf_offset_t offset,
-    std::string const& description,
-    QPDFObjGen exp_og,
-    QPDFObjGen& og,
-    bool skip_cache_if_in_xref)
-{
-    bool check_og = true;
-    if (exp_og.getObj() == 0) {
-        // This method uses an expect object ID of 0 to indicate that we don't know or don't care
-        // what the actual object ID is at this offset. This is true when we read the xref stream
-        // and linearization hint streams. In this case, we don't verify the expect object
-        // ID/generation against what was read from the file. There is also no reason to attempt
-        // xref recovery if we get a failure in this case since the read attempt was not triggered
-        // by an xref lookup.
-        check_og = false;
-        try_recovery = false;
-    }
-    qpdf.setLastObjectDescription(description, exp_og);
-
-    if (!m->attempt_recovery) {
-        try_recovery = false;
-    }
-
-    // Special case: if offset is 0, just return null.  Some PDF writers, in particular
-    // "Mac OS X 10.7.5 Quartz PDFContext", may store deleted objects in the xref table as
-    // "0000000000 00000 n", which is not correct, but it won't hurt anything for us to ignore
-    // these.
-    if (offset == 0) {
-        QTC::TC("qpdf", "QPDF bogus 0 offset", 0);
-        qpdf.warn(qpdf.damagedPDF(0, "object has offset 0"));
-        return QPDFObjectHandle::newNull();
-    }
-
-    m->file->seek(offset, SEEK_SET);
-    try {
-        QPDFTokenizer::Token tobjid = qpdf.readToken(*m->file);
-        bool objidok = tobjid.isInteger();
-        QTC::TC("qpdf", "QPDF check objid", objidok ? 1 : 0);
-        if (!objidok) {
-            QTC::TC("qpdf", "QPDF expected n n obj");
-            throw qpdf.damagedPDF(offset, "expected n n obj");
-        }
-        QPDFTokenizer::Token tgen = qpdf.readToken(*m->file);
-        bool genok = tgen.isInteger();
-        QTC::TC("qpdf", "QPDF check generation", genok ? 1 : 0);
-        if (!genok) {
-            throw qpdf.damagedPDF(offset, "expected n n obj");
-        }
-        QPDFTokenizer::Token tobj = qpdf.readToken(*m->file);
-
-        bool objok = tobj.isWord("obj");
-        QTC::TC("qpdf", "QPDF check obj", objok ? 1 : 0);
-
-        if (!objok) {
-            throw qpdf.damagedPDF(offset, "expected n n obj");
-        }
-        int objid = QUtil::string_to_int(tobjid.getValue().c_str());
-        int generation = QUtil::string_to_int(tgen.getValue().c_str());
-        og = QPDFObjGen(objid, generation);
-        if (objid == 0) {
-            QTC::TC("qpdf", "QPDF object id 0");
-            throw qpdf.damagedPDF(offset, "object with ID 0");
-        }
-        if (check_og && (exp_og != og)) {
-            QTC::TC("qpdf", "QPDF err wrong objid/generation");
-            QPDFExc e = qpdf.damagedPDF(offset, "expected " + exp_og.unparse(' ') + " obj");
-            if (try_recovery) {
-                // Will be retried below
-                throw e;
-            } else {
-                // We can try reading the object anyway even if the ID doesn't match.
-                qpdf.warn(e);
-            }
-        }
-    } catch (QPDFExc& e) {
-        if (try_recovery) {
-            // Try again after reconstructing xref table
-            xref.reconstruct(e);
-            if (xref.type(exp_og) == 1) {
-                QTC::TC("qpdf", "QPDF recovered in readObjectAtOffset");
-                return read(false, xref.offset(exp_og), description, exp_og, og, false);
-            } else {
-                QTC::TC("qpdf", "QPDF object gone after xref reconstruction");
-                qpdf.warn(qpdf.damagedPDF(
-                    "",
-                    0,
-                    ("object " + exp_og.unparse(' ') +
-                     " not found in file after regenerating cross reference table")));
-                return QPDFObjectHandle::newNull();
-            }
-        } else {
-            throw;
-        }
-    }
-
-    QPDFObjectHandle oh = read_object(description, og);
-
-    if (unresolved(og)) {
-        // Store the object in the cache here so it gets cached whether we first know the offset or
-        // whether we first know the object ID and generation (in which we case we would get here
-        // through resolve).
-
-        // Determine the end offset of this object before and after white space.  We use these
-        // numbers to validate linearization hint tables.  Offsets and lengths of objects may imply
-        // the end of an object to be anywhere between these values.
-        qpdf_offset_t end_before_space = m->file->tell();
-
-        // skip over spaces
-        while (true) {
-            char ch;
-            if (m->file->read(&ch, 1)) {
-                if (!isspace(static_cast<unsigned char>(ch))) {
-                    m->file->seek(-1, SEEK_CUR);
-                    break;
-                }
-            } else {
-                throw qpdf.damagedPDF(m->file->tell(), "EOF after endobj");
-            }
-        }
-        qpdf_offset_t end_after_space = m->file->tell();
-        if (skip_cache_if_in_xref && xref.type(og)) {
-            // Ordinarily, an object gets read here when resolved through xref table or stream. In
-            // the special case of the xref stream and linearization hint tables, the offset comes
-            // from another source. For the specific case of xref streams, the xref stream is read
-            // and loaded into the object cache very early in parsing. Ordinarily, when a file is
-            // updated by appending, items inserted into the xref table in later updates take
-            // precedence over earlier items. In the special case of reusing the object number
-            // previously used as the xref stream, we have the following order of events:
-            //
-            // * reused object gets loaded into the xref table
-            // * old object is read here while reading xref streams
-            // * original xref entry is ignored (since already in xref table)
-            //
-            // It is the second step that causes a problem. Even though the xref table is correct in
-            // this case, the old object is already in the cache and so effectively prevails over
-            // the reused object. To work around this issue, we have a special case for the xref
-            // stream (via the skip_cache_if_in_xref): if the object is already in the xref stream,
-            // don't cache what we read here.
-            //
-            // It is likely that the same bug may exist for linearization hint tables, but the
-            // existing code uses end_before_space and end_after_space from the cache, so fixing
-            // that would require more significant rework. The chances of a linearization hint
-            // stream being reused seems smaller because the xref stream is probably the highest
-            // object in the file and the linearization hint stream would be some random place in
-            // the middle, so I'm leaving that bug unfixed for now. If the bug were to be fixed, we
-            // could use !check_og in place of skip_cache_if_in_xref.
-            QTC::TC("qpdf", "QPDF skipping cache for known unchecked object");
-        } else {
-            xref.linearization_offsets(toS(og.getObj()), end_before_space, end_after_space);
-            update_table(og, oh.getObj());
-        }
-    }
-
-    return oh;
-}
-
-QPDFObject*
-Objects::resolve(QPDFObjGen og)
-{
-    if (!unresolved(og)) {
-        return table[og].object.get();
-    }
-
-    if (m->resolving.count(og)) {
-        // This can happen if an object references itself directly or indirectly in some key that
-        // has to be resolved during object parsing, such as stream length.
-        QTC::TC("qpdf", "QPDF recursion loop in resolve");
-        qpdf.warn(qpdf.damagedPDF("", "loop detected resolving object " + og.unparse(' ')));
-        update_table(og, QPDF_Null::create());
-        return table[og].object.get();
-    }
-    ResolveRecorder rr(&qpdf, og);
-
-    try {
-        switch (xref.type(og)) {
-        case 0:
-            break;
-        case 1:
-            {
-                // Object stored in cache by readObjectAtOffset
-                QPDFObjGen a_og;
-                QPDFObjectHandle oh = read(true, xref.offset(og), "", og, a_og, false);
-            }
-            break;
-
-        case 2:
-            resolveObjectsInStream(xref.stream_number(og.getObj()));
-            break;
-
-        default:
-            throw qpdf.damagedPDF(
-                "", 0, ("object " + og.unparse('/') + " has unexpected xref entry type"));
-        }
-    } catch (QPDFExc& e) {
-        qpdf.warn(e);
-    } catch (std::exception& e) {
-        qpdf.warn(qpdf.damagedPDF(
-            "", 0, ("object " + og.unparse('/') + ": error reading object: " + e.what())));
-    }
-
-    if (unresolved(og)) {
-        // PDF spec says unknown objects resolve to the null object.
-        QTC::TC("qpdf", "QPDF resolve failure to null");
-        update_table(og, QPDF_Null::create());
-    }
-
-    auto result(table[og].object);
-    result->setDefaultDescription(&qpdf, og);
-    return result.get();
-}
-
-void
-Objects::resolveObjectsInStream(int obj_stream_number)
-{
-    if (m->resolved_object_streams.count(obj_stream_number)) {
-        return;
-    }
-    m->resolved_object_streams.insert(obj_stream_number);
-    // Force resolution of object stream
-    QPDFObjectHandle obj_stream = get(obj_stream_number, 0);
-    if (!obj_stream.isStream()) {
-        throw qpdf.damagedPDF(
-            "supposed object stream " + std::to_string(obj_stream_number) + " is not a stream");
-    }
-
-    QPDFObjectHandle dict = obj_stream.getDict();
-    if (!dict.isDictionaryOfType("/ObjStm")) {
-        QTC::TC("qpdf", "QPDF ERR object stream with wrong type");
-        qpdf.warn(qpdf.damagedPDF(
-            "supposed object stream " + std::to_string(obj_stream_number) + " has wrong type"));
-    }
-
-    if (!(dict.getKey("/N").isInteger() && dict.getKey("/First").isInteger())) {
-        throw qpdf.damagedPDF(
-            ("object stream " + std::to_string(obj_stream_number) + " has incorrect keys"));
-    }
-
-    int n = dict.getKey("/N").getIntValueAsInt();
-    int first = dict.getKey("/First").getIntValueAsInt();
-
-    std::map<int, int> offsets;
-
-    std::shared_ptr<Buffer> bp = obj_stream.getStreamData(qpdf_dl_specialized);
-    auto input = std::shared_ptr<InputSource>(
-        // line-break
-        new BufferInputSource(
-            (m->file->getName() + " object stream " + std::to_string(obj_stream_number)),
-            bp.get()));
-
-    qpdf_offset_t last_offset = -1;
-    for (int i = 0; i < n; ++i) {
-        QPDFTokenizer::Token tnum = qpdf.readToken(*input);
-        QPDFTokenizer::Token toffset = qpdf.readToken(*input);
-        if (!(tnum.isInteger() && toffset.isInteger())) {
-            throw damagedPDF(
-                *input,
-                m->last_object_description,
-                input->getLastOffset(),
-                "expected integer in object stream header");
-        }
-
-        int num = QUtil::string_to_int(tnum.getValue().c_str());
-        long long offset = QUtil::string_to_int(toffset.getValue().c_str());
-        if (num > xref.max_id()) {
-            continue;
-        }
-        if (num == obj_stream_number) {
-            QTC::TC("qpdf", "QPDF ignore self-referential object stream");
-            qpdf.warn(damagedPDF(
-                *input,
-                m->last_object_description,
-                input->getLastOffset(),
-                "object stream claims to contain itself"));
-            continue;
-        }
-        if (offset <= last_offset) {
-            throw damagedPDF(
-                *input,
-                m->last_object_description,
-                input->getLastOffset(),
-                "expected offsets in object stream to be increasing");
-        }
-        last_offset = offset;
-
-        offsets[num] = toI(offset + first);
-    }
-
-    // To avoid having to read the object stream multiple times, store all objects that would be
-    // found here in the cache.  Remember that some objects stored here might have been overridden
-    // by new objects appended to the file, so it is necessary to recheck the xref table and only
-    // cache what would actually be resolved here.
-    m->last_object_description.clear();
-    m->last_object_description += "object ";
-    for (auto const& iter: offsets) {
-        QPDFObjGen og(iter.first, 0);
-        if (xref.type(og) == 2 && xref.stream_number(og.getObj()) == obj_stream_number) {
-            int offset = iter.second;
-            input->seek(offset, SEEK_SET);
-            QPDFObjectHandle oh = readObjectInStream(input, iter.first);
-            update_table(og, oh.getObj());
-        } else {
-            QTC::TC("qpdf", "QPDF not caching overridden objstm object");
-        }
-    }
-}
-
-Objects::~Objects()
-{
-    // If two objects are mutually referential (through each object having an array or dictionary
-    // that contains an indirect reference to the other), the circular references in the
-    // std::shared_ptr objects will prevent the objects from being deleted. Walk through all objects
-    // in the object cache, which is those objects that we read from the file, and break all
-    // resolved indirect references by replacing them with an internal object type representing that
-    // they have been destroyed. Note that we can't break references like this at any time when the
-    // QPDF object is active. The call to reset also causes all direct QPDFObjectHandle objects that
-    // are reachable from this object to release their association with this QPDF. Direct objects
-    // are not destroyed since they can be moved to other QPDF objects safely.
-
-    for (auto const& iter: table) {
-        iter.second.object->disconnect();
-        if (iter.second.object->getTypeCode() != ::ot_null) {
-            iter.second.object->destroy();
-        }
-    }
-}
-
-void
-Objects::update_table(QPDFObjGen og, const std::shared_ptr<QPDFObject>& object)
-{
-    object->setObjGen(&qpdf, og);
-    if (cached(og)) {
-        auto& cache = table[og];
-        cache.object->assign(object);
-    } else {
-        table[og] = Entry(object);
-    }
-}
-
-bool
-Objects::cached(QPDFObjGen og)
-{
-    return table.count(og) != 0;
-}
-
-bool
-Objects::unresolved(QPDFObjGen og)
-{
-    return !cached(og) || table[og].object->isUnresolved();
-}
-
-QPDFObjGen
-Objects::next_id()
-{
-    qpdf.fixDanglingReferences();
-    QPDFObjGen og;
-    if (!table.empty()) {
-        og = (*(m->objects.table.rbegin())).first;
-    }
-    int max_objid = og.getObj();
-    if (max_objid == std::numeric_limits<int>::max()) {
-        throw std::range_error("max object id is too high to create new objects");
-    }
-    return QPDFObjGen(max_objid + 1, 0);
-}
-
-QPDFObjectHandle
-Objects::make_indirect(std::shared_ptr<QPDFObject> const& obj)
-{
-    QPDFObjGen next{next_id()};
-    table[next] = Entry(obj);
-    return qpdf.newIndirect(next, table[next].object);
-}
-
-std::shared_ptr<QPDFObject>
-Objects::get_for_parser(int id, int gen, bool parse_pdf)
-{
-    // This method is called by the parser and therefore must not resolve any objects.
-    auto og = QPDFObjGen(id, gen);
-    if (auto iter = table.find(og); iter != table.end()) {
-        return iter->second.object;
-    }
-    if (xref.type(og) || !xref.initialized()) {
-        return table.insert({og, QPDF_Unresolved::create(&qpdf, og)}).first->second.object;
-    }
-    if (parse_pdf) {
-        return QPDF_Null::create();
-    }
-    return table.insert({og, QPDF_Null::create(&qpdf, og)}).first->second.object;
-}
-
-std::shared_ptr<QPDFObject>
-Objects::get_for_json(int id, int gen)
-{
-    auto og = QPDFObjGen(id, gen);
-    auto [it, inserted] = table.try_emplace(og);
-    auto& obj = it->second.object;
-    if (inserted) {
-        obj = (xref.initialized() && !xref.type(og)) ? QPDF_Null::create(&qpdf, og)
-                                                     : QPDF_Unresolved::create(&qpdf, og);
-    }
-    return obj;
-}
-
-void
-Objects::replace(QPDFObjGen og, QPDFObjectHandle oh)
-{
-    if (!oh || (oh.isIndirect() && !(oh.isStream() && oh.getObjGen() == og))) {
-        QTC::TC("qpdf", "QPDF replaceObject called with indirect object");
-        throw std::logic_error("QPDF::replaceObject called with indirect object handle");
-    }
-    update_table(og, oh.getObj());
-}
-
-void
-Objects::erase(QPDFObjGen og)
-{
-    if (auto cached = table.find(og); cached != table.end()) {
-        // Take care of any object handles that may be floating around.
-        cached->second.object->assign(QPDF_Null::create());
-        cached->second.object->setObjGen(nullptr, QPDFObjGen());
-        table.erase(cached);
-    }
-}
-
-void
-Objects::swap(QPDFObjGen og1, QPDFObjGen og2)
-{
-    // Force objects to be read from the input source if needed, then swap them in the cache.
-    resolve(og1);
-    resolve(og2);
-    table[og1].object->swapWith(table[og2].object);
-}
-
-size_t
-Objects::table_size()
-{
-    // If table is dense, accommodate all object in tables,else accommodate only original
-    // objects.
-    auto max_xref = toI(xref.size());
-    if (max_xref > 0) {
-        --max_xref;
-    }
-    auto max_obj = table.size() ? table.crbegin()->first.getObj() : 0;
-    auto max_id = std::numeric_limits<int>::max() - 1;
-    if (max_obj >= max_id || max_xref >= max_id) {
-        // Temporary fix. Long-term solution is
-        // - QPDFObjGen to enforce objgens are valid and sensible
-        // - xref table and obj cache to protect against insertion of impossibly large obj ids
-        qpdf.stopOnError("Impossibly large object id encountered.");
-    }
-    if (max_obj < 1.1 * std::max(toI(table.size()), max_xref)) {
-        return toS(++max_obj);
-    }
-    return toS(++max_xref);
-}
-
-std::vector<QPDFObjGen>
-Objects::compressible_vector()
-{
-    return compressible<QPDFObjGen>();
-}
-
-std::vector<bool>
-Objects::compressible_set()
-{
-    return compressible<bool>();
-}
-
-template <typename T>
-std::vector<T>
-Objects::compressible()
-{
-    // Return a list of objects that are allowed to be in object streams.  Walk through the objects
-    // by traversing the document from the root, including a traversal of the pages tree.  This
-    // makes that objects that are on the same page are more likely to be in the same object stream,
-    // which is slightly more efficient, particularly with linearized files.  This is better than
-    // iterating through the xref table since it avoids preserving orphaned items.
-
-    // Exclude encryption dictionary, if any
-    QPDFObjectHandle encryption_dict = trailer().getKey("/Encrypt");
-    QPDFObjGen encryption_dict_og = encryption_dict.getObjGen();
-
-    const size_t max_obj = qpdf.getObjectCount();
-    std::vector<bool> visited(max_obj, false);
-    std::vector<QPDFObjectHandle> queue;
-    queue.reserve(512);
-    queue.emplace_back(trailer());
-    std::vector<T> result;
-    if constexpr (std::is_same_v<T, QPDFObjGen>) {
-        result.reserve(table.size());
-    } else if constexpr (std::is_same_v<T, bool>) {
-        result.resize(max_obj + 1U, false);
-    } else {
-        throw std::logic_error("Unsupported type in QPDF::getCompressibleObjGens");
-    }
-    while (!queue.empty()) {
-        auto obj = queue.back();
-        queue.pop_back();
-        if (obj.getObjectID() > 0) {
-            QPDFObjGen og = obj.getObjGen();
-            const size_t id = toS(og.getObj() - 1);
-            if (id >= max_obj) {
-                throw std::logic_error(
-                    "unexpected object id encountered in getCompressibleObjGens");
-            }
-            if (visited[id]) {
-                QTC::TC("qpdf", "QPDF loop detected traversing objects");
-                continue;
-            }
-
-            // Check whether this is the current object. If not, remove it (which changes it into a
-            // direct null and therefore stops us from revisiting it) and move on to the next object
-            // in the queue.
-            auto upper = table.upper_bound(og);
-            if (upper != table.end() && upper->first.getObj() == og.getObj()) {
-                erase(og);
-                continue;
-            }
-
-            visited[id] = true;
-
-            if (og == encryption_dict_og) {
-                QTC::TC("qpdf", "QPDF exclude encryption dictionary");
-            } else if (!(obj.isStream() ||
-                         (obj.isDictionaryOfType("/Sig") && obj.hasKey("/ByteRange") &&
-                          obj.hasKey("/Contents")))) {
-                if constexpr (std::is_same_v<T, QPDFObjGen>) {
-                    result.push_back(og);
-                } else if constexpr (std::is_same_v<T, bool>) {
-                    result[id + 1U] = true;
-                }
-            }
-        }
-        if (obj.isStream()) {
-            QPDFObjectHandle dict = obj.getDict();
-            std::set<std::string> keys = dict.getKeys();
-            for (auto iter = keys.rbegin(); iter != keys.rend(); ++iter) {
-                std::string const& key = *iter;
-                QPDFObjectHandle value = dict.getKey(key);
-                if (key == "/Length") {
-                    // omit stream lengths
-                    if (value.isIndirect()) {
-                        QTC::TC("qpdf", "QPDF exclude indirect length");
-                    }
-                } else {
-                    queue.push_back(value);
-                }
-            }
-        } else if (obj.isDictionary()) {
-            std::set<std::string> keys = obj.getKeys();
-            for (auto iter = keys.rbegin(); iter != keys.rend(); ++iter) {
-                queue.push_back(obj.getKey(*iter));
-            }
-        } else if (obj.isArray()) {
-            int n = obj.getArrayNItems();
-            for (int i = 1; i <= n; ++i) {
-                queue.push_back(obj.getArrayItem(n - i));
-            }
-        }
-    }
-
-    return result;
-}
@@ -79,9 +79,9 @@ QPDF::optimize(
 }
 void
-QPDF::optimize(QPDF::Objects const& objects)
+QPDF::optimize(QPDF::Xref_table const& xref)
 {
-    optimize_internal(objects, false, nullptr);
+    optimize_internal(xref, false, nullptr);
 }
 template <typename T>
@@ -121,13 +121,13 @@ QPDF::optimize_internal(
     }
     // Traverse document-level items
-    for (auto const& key: m->objects.trailer().getKeys()) {
+    for (auto const& key: m->xref_table.trailer().getKeys()) {
         if (key == "/Root") {
             // handled separately
         } else {
             updateObjectMaps(
                 ObjUser(ObjUser::ou_trailer_key, key),
-                m->objects.trailer().getKey(key),
+                m->xref_table.trailer().getKey(key),
                 skip_stream_parameters);
         }
     }
@@ -175,7 +175,7 @@ QPDF::pushInheritedAttributesToPage(bool allow_changes, bool warn_skipped_keys)
     // values for them.
     std::map<std::string, std::vector<QPDFObjectHandle>> key_ancestors;
     pushInheritedAttributesToPageInternal(
-        m->objects.trailer().getKey("/Root").getKey("/Pages"),
+        m->xref_table.trailer().getKey("/Root").getKey("/Pages"),
         key_ancestors,
         allow_changes,
         warn_skipped_keys);
@@ -450,9 +450,8 @@ QPDF::filterCompressedObjects(QPDFWriter::ObjTable const&amp; obj)
 }
 void
-QPDF::filterCompressedObjects(QPDF::Objects const& objects)
+QPDF::filterCompressedObjects(QPDF::Xref_table const& xref)
 {
-    auto const& xref = objects.xref_table();
     if (!xref.object_streams()) {
         return;
     }
@@ -905,7 +905,7 @@ qpdf_oh
 qpdf_get_object_by_id(qpdf_data qpdf, int objid, int generation)
 {
     QTC::TC("qpdf", "qpdf-c called qpdf_get_object_by_id");
-    return new_object(qpdf, qpdf->qpdf->getObject(objid, generation));
+    return new_object(qpdf, qpdf->qpdf->getObjectByID(objid, generation));
 }
 template <class RET>
-#ifndef QPDF_OBJECTS_HH
-#define QPDF_OBJECTS_HH
-
-#include <qpdf/QPDF.hh>
-
-#include <qpdf/QPDF_Null.hh>
-#include <qpdf/QPDF_Unresolved.hh>
-
-#include <variant>
-
-// The Objects class is responsible for keeping track of all objects belonging to a QPDF instance,
-// including loading it from an input source when required.
-class QPDF::Objects
-{
-  public:
-    // Xref_table encapsulates the pdf's xref table and trailer.
-    class Xref_table
-    {
-      public:
-        Xref_table(Objects& objects) :
-            qpdf(objects.qpdf),
-            objects(objects),
-            file(objects.file)
-        {
-            tokenizer.allowEOF();
-        }
-
-        void initialize();
-        void initialize_empty();
-        void initialize_json();
-        void reconstruct(QPDFExc& e);
-        void show();
-        bool resolve();
-
-        QPDFObjectHandle
-        trailer() noexcept
-        {
-            return trailer_;
-        }
-
-        QPDFObjectHandle const&
-        trailer() const noexcept
-        {
-            return trailer_;
-        }
-
-        void
-        trailer(QPDFObjectHandle&& oh)
-        {
-            trailer_ = std::move(oh);
-        }
-
-        // Returns 0 if og is not in table.
-        size_t
-        type(QPDFObjGen og) const
-        {
-            int id = og.getObj();
-            if (id < 1 || static_cast<size_t>(id) >= table.size()) {
-                return 0;
-            }
-            auto& e = table[static_cast<size_t>(id)];
-            return e.gen() == og.getGen() ? e.type() : 0;
-        }
-
-        // Returns 0 if og is not in table.
-        size_t
-        type(size_t id) const noexcept
-        {
-            if (id >= table.size()) {
-                return 0;
-            }
-            return table[id].type();
-        }
-
-        // Returns 0 if og is not in table.
-        qpdf_offset_t
-        offset(QPDFObjGen og) const noexcept
-        {
-            int id = og.getObj();
-            if (id < 1 || static_cast<size_t>(id) >= table.size()) {
-                return 0;
-            }
-            return table[static_cast<size_t>(id)].offset();
-        }
-
-        // Returns 0 if id is not in table.
-        int
-        stream_number(int id) const noexcept
-        {
-            if (id < 1 || static_cast<size_t>(id) >= table.size()) {
-                return 0;
-            }
-            return table[static_cast<size_t>(id)].stream_number();
-        }
-
-        int
-        stream_index(int id) const noexcept
-        {
-            if (id < 1 || static_cast<size_t>(id) >= table.size()) {
-                return 0;
-            }
-            return table[static_cast<size_t>(id)].stream_index();
-        }
-
-        QPDFObjGen at_offset(qpdf_offset_t offset) const noexcept;
-
-        std::map<QPDFObjGen, QPDFXRefEntry> as_map() const;
-
-        bool
-        object_streams() const noexcept
-        {
-            return object_streams_;
-        }
-
-        // Return a vector of object id and stream number for each compressed object.
-        std::vector<std::pair<unsigned int, int>>
-        compressed_objects() const
-        {
-            if (!initialized()) {
-                throw std::logic_error("Xref_table::compressed_objects called before parsing.");
-            }
-
-            std::vector<std::pair<unsigned int, int>> result;
-            result.reserve(table.size());
-
-            unsigned int i{0};
-            for (auto const& item: table) {
-                if (item.type() == 2) {
-                    result.emplace_back(i, item.stream_number());
-                }
-                ++i;
-            }
-            return result;
-        }
-
-        // Temporary access to underlying table size
-        size_t
-        size() const noexcept
-        {
-            return table.size();
-        }
-
-        void
-        ignore_streams(bool val) noexcept
-        {
-            ignore_streams_ = val;
-        }
-
-        bool
-        initialized() const noexcept
-        {
-            return initialized_;
-        }
-
-        void
-        attempt_recovery(bool val) noexcept
-        {
-            attempt_recovery_ = val;
-        }
-
-        int
-        max_id() const noexcept
-        {
-            return max_id_;
-        }
-
-        // For Linearization
-
-        qpdf_offset_t
-        end_after_space(QPDFObjGen og)
-        {
-            auto& e = entry(toS(og.getObj()));
-            switch (e.type()) {
-            case 1:
-                return e.end_after_space_;
-            case 2:
-                {
-                    auto es = entry(toS(e.stream_number()));
-                    return es.type() == 1 ? es.end_after_space_ : 0;
-                }
-            default:
-                return 0;
-            }
-        }
-
-        qpdf_offset_t
-        end_before_space(QPDFObjGen og)
-        {
-            auto& e = entry(toS(og.getObj()));
-            switch (e.type()) {
-            case 1:
-                return e.end_before_space_;
-            case 2:
-                {
-                    auto es = entry(toS(e.stream_number()));
-                    return es.type() == 1 ? es.end_before_space_ : 0;
-                }
-            default:
-                return 0;
-            }
-        }
-
-        void
-        linearization_offsets(size_t id, qpdf_offset_t before, qpdf_offset_t after)
-        {
-            if (type(id)) {
-                table[id].end_before_space_ = before;
-                table[id].end_after_space_ = after;
-            }
-        }
-
-        bool
-        uncompressed_after_compressed() const noexcept
-        {
-            return uncompressed_after_compressed_;
-        }
-
-        // Actual value from file
-        qpdf_offset_t
-        first_item_offset() const noexcept
-        {
-            return first_item_offset_;
-        }
-
-      private:
-        // Object, count, offset of first entry
-        typedef std::tuple<int, int, qpdf_offset_t> Subsection;
-
-        struct Uncompressed
-        {
-            Uncompressed(qpdf_offset_t offset) :
-                offset(offset)
-            {
-            }
-            qpdf_offset_t offset;
-        };
-
-        struct Compressed
-        {
-            Compressed(int stream_number, int stream_index) :
-                stream_number(stream_number),
-                stream_index(stream_index)
-            {
-            }
-            int stream_number{0};
-            int stream_index{0};
-        };
-
-        typedef std::variant<std::monostate, Uncompressed, Compressed> Xref;
-
-        struct Entry
-        {
-            Entry() = default;
-
-            Entry(int gen, Xref entry) :
-                gen_(gen),
-                entry(entry)
-            {
-            }
-
-            int
-            gen() const noexcept
-            {
-                return gen_;
-            }
-
-            size_t
-            type() const noexcept
-            {
-                return entry.index();
-            }
-
-            qpdf_offset_t
-            offset() const noexcept
-            {
-                return type() == 1 ? std::get<1>(entry).offset : 0;
-            }
-
-            int
-            stream_number() const noexcept
-            {
-                return type() == 2 ? std::get<2>(entry).stream_number : 0;
-            }
-
-            int
-            stream_index() const noexcept
-            {
-                return type() == 2 ? std::get<2>(entry).stream_index : 0;
-            }
-
-            int gen_{0};
-            Xref entry;
-            qpdf_offset_t end_before_space_{0};
-            qpdf_offset_t end_after_space_{0};
-        };
-
-        Entry&
-        entry(size_t id)
-        {
-            return id < table.size() ? table[id] : table[0];
-        }
-
-        void read(qpdf_offset_t offset);
-
-        // Methods to parse tables
-        qpdf_offset_t process_section(qpdf_offset_t offset);
-        std::vector<Subsection> subsections(std::string& line);
-        std::vector<Subsection> bad_subsections(std::string& line, qpdf_offset_t offset);
-        Subsection subsection(std::string const& line);
-        std::tuple<bool, qpdf_offset_t, int, char> read_entry();
-        std::tuple<bool, qpdf_offset_t, int, char> read_bad_entry();
-
-        // Methods to parse streams
-        qpdf_offset_t read_stream(qpdf_offset_t offset);
-        qpdf_offset_t process_stream(qpdf_offset_t offset, QPDFObjectHandle& xref_stream);
-        std::pair<int, std::array<int, 3>>
-        process_W(QPDFObjectHandle& dict, std::function<QPDFExc(std::string_view)> damaged);
-        std::pair<int, size_t> process_Size(
-            QPDFObjectHandle& dict,
-            int entry_size,
-            std::function<QPDFExc(std::string_view)> damaged);
-        std::pair<int, std::vector<std::pair<int, int>>> process_Index(
-            QPDFObjectHandle& dict,
-            int max_num_entries,
-            std::function<QPDFExc(std::string_view)> damaged);
-
-        QPDFObjectHandle read_trailer();
-
-        QPDFTokenizer::Token
-        read_token(size_t max_len = 0)
-        {
-            return tokenizer.readToken(*file, "", true, max_len);
-        }
-
-        // Methods to insert table entries
-        void insert(int obj, int f0, qpdf_offset_t f1, int f2);
-        void insert_free(QPDFObjGen);
-
-        QPDFExc
-        damaged_pdf(std::string const& msg)
-        {
-            return qpdf.damagedPDF("", 0, msg);
-        }
-
-        QPDFExc
-        damaged_table(std::string const& msg)
-        {
-            return qpdf.damagedPDF("xref table", msg);
-        }
-
-        void
-        warn_damaged(std::string const& msg)
-        {
-            qpdf.warn(damaged_pdf(msg));
-        }
-
-        QPDF& qpdf;
-        QPDF::Objects& objects;
-        InputSource* const& file;
-        QPDFTokenizer tokenizer;
-
-        std::vector<Entry> table;
-        QPDFObjectHandle trailer_;
-
-        bool attempt_recovery_{true};
-        bool initialized_{false};
-        bool ignore_streams_{false};
-        bool reconstructed_{false};
-        bool object_streams_{false};
-        // Before the xref table is initialized, max_id_ is an upper bound on the possible object
-        // ids that could be present in the PDF file. Once the trailer has been read, max_id_ is set
-        // to the value of /Size. If the file is damaged, max_id_ becomes the maximum object id in
-        // the xref table after reconstruction.
-        int max_id_{std::numeric_limits<int>::max() - 1};
-
-        // Linearization data
-        bool uncompressed_after_compressed_{false};
-        qpdf_offset_t first_item_offset_{0}; // actual value from file
-    }; // Xref_table;
-
-    ~Objects();
-
-    Objects(QPDF& qpdf, QPDF::Members* m, InputSource* const& file) :
-        qpdf(qpdf),
-        file(file),
-        m(m),
-        xref(*this)
-    {
-    }
-
-    Xref_table&
-    xref_table() noexcept
-    {
-        return xref;
-    }
-
-    Xref_table const&
-    xref_table() const noexcept
-    {
-        return xref;
-    }
-
-    QPDFObjectHandle
-    trailer() noexcept
-    {
-        return xref.trailer();
-    }
-
-    QPDFObjectHandle const&
-    trailer() const noexcept
-    {
-        return xref.trailer();
-    }
-
-    QPDFObjectHandle
-    get(QPDFObjGen og)
-    {
-        if (auto it = table.find(og); it != table.end()) {
-            return {it->second.object};
-        } else if (xref.initialized() && !xref.type(og)) {
-            return QPDF_Null::create();
-        } else {
-            auto result = table.try_emplace(og, QPDF_Unresolved::create(&qpdf, og));
-            return {result.first->second.object};
-        }
-    }
-
-    QPDFObjectHandle
-    get(int id, int gen)
-    {
-        return get(QPDFObjGen(id, gen));
-    }
-
-    std::vector<QPDFObjectHandle> all();
-
-    void erase(QPDFObjGen og);
-
-    void replace(QPDFObjGen og, QPDFObjectHandle oh);
-
-    void swap(QPDFObjGen og1, QPDFObjGen og2);
-
-    QPDFObjectHandle read(
-        bool attempt_recovery,
-        qpdf_offset_t offset,
-        std::string const& description,
-        QPDFObjGen exp_og,
-        QPDFObjGen& og,
-        bool skip_cache_if_in_xref);
-    QPDFObject* resolve(QPDFObjGen og);
-    void update_table(QPDFObjGen og, std::shared_ptr<QPDFObject> const& object);
-    QPDFObjGen next_id();
-    QPDFObjectHandle make_indirect(std::shared_ptr<QPDFObject> const& obj);
-    std::shared_ptr<QPDFObject> get_for_parser(int id, int gen, bool parse_pdf);
-    std::shared_ptr<QPDFObject> get_for_json(int id, int gen);
-
-    // Get a list of objects that would be permitted in an object stream.
-    template <typename T>
-    std::vector<T> compressible();
-    std::vector<QPDFObjGen> compressible_vector();
-    std::vector<bool> compressible_set();
-
-    // Used by QPDFWriter to determine the vector part of its object tables.
-    size_t table_size();
-
-  private:
-    struct Entry
-    {
-        Entry() = default;
-
-        Entry(std::shared_ptr<QPDFObject> object) :
-            object(object)
-        {
-        }
-
-        std::shared_ptr<QPDFObject> object;
-    };
-
-    bool cached(QPDFObjGen og);
-    bool unresolved(QPDFObjGen og);
-
-    QPDFObjectHandle readObjectInStream(std::shared_ptr<InputSource>& input, int obj);
-    void resolveObjectsInStream(int obj_stream_number);
-    QPDFObjectHandle read_object(std::string const& description, QPDFObjGen og);
-    void read_stream(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset);
-    void validate_stream_line_end(QPDFObjectHandle& object, QPDFObjGen og, qpdf_offset_t offset);
-    size_t recover_stream_length(
-        std::shared_ptr<InputSource> input, QPDFObjGen og, qpdf_offset_t stream_offset);
-
-    QPDF& qpdf;
-    InputSource* const& file;
-    QPDF::Members* m;
-    Xref_table xref;
-
-    std::map<QPDFObjGen, Entry> table;
-}; // Objects
-
-#endif // QPDF_OBJECTS_HH
@@ -3,10 +3,378 @@
 #include <qpdf/QPDF.hh>
-#include <qpdf/QPDF_objects.hh>
-
 #include <variant>
+// Xref_table encapsulates the pdf's xref table and trailer.
+class QPDF::Xref_table
+{
+  public:
+    Xref_table(QPDF& qpdf, InputSource* const& file) :
+        qpdf(qpdf),
+        file(file)
+    {
+        tokenizer.allowEOF();
+    }
+
+    void initialize();
+    void initialize_empty();
+    void initialize_json();
+    void reconstruct(QPDFExc& e);
+    void show();
+    bool resolve();
+
+    QPDFObjectHandle
+    trailer() const
+    {
+        return trailer_;
+    }
+
+    void
+    trailer(QPDFObjectHandle&& oh)
+    {
+        trailer_ = std::move(oh);
+    }
+
+    // Returns 0 if og is not in table.
+    size_t
+    type(QPDFObjGen og) const
+    {
+        int id = og.getObj();
+        if (id < 1 || static_cast<size_t>(id) >= table.size()) {
+            return 0;
+        }
+        auto& e = table[static_cast<size_t>(id)];
+        return e.gen() == og.getGen() ? e.type() : 0;
+    }
+
+    // Returns 0 if og is not in table.
+    size_t
+    type(size_t id) const noexcept
+    {
+        if (id >= table.size()) {
+            return 0;
+        }
+        return table[id].type();
+    }
+
+    // Returns 0 if og is not in table.
+    qpdf_offset_t
+    offset(QPDFObjGen og) const noexcept
+    {
+        int id = og.getObj();
+        if (id < 1 || static_cast<size_t>(id) >= table.size()) {
+            return 0;
+        }
+        return table[static_cast<size_t>(id)].offset();
+    }
+
+    // Returns 0 if id is not in table.
+    int
+    stream_number(int id) const noexcept
+    {
+        if (id < 1 || static_cast<size_t>(id) >= table.size()) {
+            return 0;
+        }
+        return table[static_cast<size_t>(id)].stream_number();
+    }
+
+    int
+    stream_index(int id) const noexcept
+    {
+        if (id < 1 || static_cast<size_t>(id) >= table.size()) {
+            return 0;
+        }
+        return table[static_cast<size_t>(id)].stream_index();
+    }
+
+    QPDFObjGen at_offset(qpdf_offset_t offset) const noexcept;
+
+    std::map<QPDFObjGen, QPDFXRefEntry> as_map() const;
+
+    bool
+    object_streams() const noexcept
+    {
+        return object_streams_;
+    }
+
+    // Return a vector of object id and stream number for each compressed object.
+    std::vector<std::pair<unsigned int, int>>
+    compressed_objects() const
+    {
+        if (!initialized()) {
+            throw std::logic_error("Xref_table::compressed_objects called before parsing.");
+        }
+
+        std::vector<std::pair<unsigned int, int>> result;
+        result.reserve(table.size());
+
+        unsigned int i{0};
+        for (auto const& item: table) {
+            if (item.type() == 2) {
+                result.emplace_back(i, item.stream_number());
+            }
+            ++i;
+        }
+        return result;
+    }
+
+    // Temporary access to underlying table size
+    size_t
+    size() const noexcept
+    {
+        return table.size();
+    }
+
+    void
+    ignore_streams(bool val) noexcept
+    {
+        ignore_streams_ = val;
+    }
+
+    bool
+    initialized() const noexcept
+    {
+        return initialized_;
+    }
+
+    void
+    attempt_recovery(bool val) noexcept
+    {
+        attempt_recovery_ = val;
+    }
+
+    int
+    max_id() const noexcept
+    {
+        return max_id_;
+    }
+
+    // For Linearization
+
+    qpdf_offset_t
+    end_after_space(QPDFObjGen og)
+    {
+        auto& e = entry(toS(og.getObj()));
+        switch (e.type()) {
+        case 1:
+            return e.end_after_space_;
+        case 2:
+            {
+                auto es = entry(toS(e.stream_number()));
+                return es.type() == 1 ? es.end_after_space_ : 0;
+            }
+        default:
+            return 0;
+        }
+    }
+
+    qpdf_offset_t
+    end_before_space(QPDFObjGen og)
+    {
+        auto& e = entry(toS(og.getObj()));
+        switch (e.type()) {
+        case 1:
+            return e.end_before_space_;
+        case 2:
+            {
+                auto es = entry(toS(e.stream_number()));
+                return es.type() == 1 ? es.end_before_space_ : 0;
+            }
+        default:
+            return 0;
+        }
+    }
+
+    void
+    linearization_offsets(size_t id, qpdf_offset_t before, qpdf_offset_t after)
+    {
+        if (type(id)) {
+            table[id].end_before_space_ = before;
+            table[id].end_after_space_ = after;
+        }
+    }
+
+    bool
+    uncompressed_after_compressed() const noexcept
+    {
+        return uncompressed_after_compressed_;
+    }
+
+    // Actual value from file
+    qpdf_offset_t
+    first_item_offset() const noexcept
+    {
+        return first_item_offset_;
+    }
+
+  private:
+    // Object, count, offset of first entry
+    typedef std::tuple<int, int, qpdf_offset_t> Subsection;
+
+    struct Uncompressed
+    {
+        Uncompressed(qpdf_offset_t offset) :
+            offset(offset)
+        {
+        }
+        qpdf_offset_t offset;
+    };
+
+    struct Compressed
+    {
+        Compressed(int stream_number, int stream_index) :
+            stream_number(stream_number),
+            stream_index(stream_index)
+        {
+        }
+        int stream_number{0};
+        int stream_index{0};
+    };
+
+    typedef std::variant<std::monostate, Uncompressed, Compressed> Xref;
+
+    struct Entry
+    {
+        Entry() = default;
+
+        Entry(int gen, Xref entry) :
+            gen_(gen),
+            entry(entry)
+        {
+        }
+
+        int
+        gen() const noexcept
+        {
+            return gen_;
+        }
+
+        size_t
+        type() const noexcept
+        {
+            return entry.index();
+        }
+
+        qpdf_offset_t
+        offset() const noexcept
+        {
+            return type() == 1 ? std::get<1>(entry).offset : 0;
+        }
+
+        int
+        stream_number() const noexcept
+        {
+            return type() == 2 ? std::get<2>(entry).stream_number : 0;
+        }
+
+        int
+        stream_index() const noexcept
+        {
+            return type() == 2 ? std::get<2>(entry).stream_index : 0;
+        }
+
+        int gen_{0};
+        Xref entry;
+        qpdf_offset_t end_before_space_{0};
+        qpdf_offset_t end_after_space_{0};
+    };
+
+    Entry&
+    entry(size_t id)
+    {
+        return id < table.size() ? table[id] : table[0];
+    }
+
+    void read(qpdf_offset_t offset);
+
+    // Methods to parse tables
+    qpdf_offset_t process_section(qpdf_offset_t offset);
+    std::vector<Subsection> subsections(std::string& line);
+    std::vector<Subsection> bad_subsections(std::string& line, qpdf_offset_t offset);
+    Subsection subsection(std::string const& line);
+    std::tuple<bool, qpdf_offset_t, int, char> read_entry();
+    std::tuple<bool, qpdf_offset_t, int, char> read_bad_entry();
+
+    // Methods to parse streams
+    qpdf_offset_t read_stream(qpdf_offset_t offset);
+    qpdf_offset_t process_stream(qpdf_offset_t offset, QPDFObjectHandle& xref_stream);
+    std::pair<int, std::array<int, 3>>
+    process_W(QPDFObjectHandle& dict, std::function<QPDFExc(std::string_view)> damaged);
+    std::pair<int, size_t> process_Size(
+        QPDFObjectHandle& dict, int entry_size, std::function<QPDFExc(std::string_view)> damaged);
+    std::pair<int, std::vector<std::pair<int, int>>> process_Index(
+        QPDFObjectHandle& dict,
+        int max_num_entries,
+        std::function<QPDFExc(std::string_view)> damaged);
+
+    QPDFObjectHandle read_trailer();
+
+    QPDFTokenizer::Token
+    read_token(size_t max_len = 0)
+    {
+        return tokenizer.readToken(*file, "", true, max_len);
+    }
+
+    // Methods to insert table entries
+    void insert(int obj, int f0, qpdf_offset_t f1, int f2);
+    void insert_free(QPDFObjGen);
+
+    QPDFExc
+    damaged_pdf(std::string const& msg)
+    {
+        return qpdf.damagedPDF("", 0, msg);
+    }
+
+    QPDFExc
+    damaged_table(std::string const& msg)
+    {
+        return qpdf.damagedPDF("xref table", msg);
+    }
+
+    void
+    warn_damaged(std::string const& msg)
+    {
+        qpdf.warn(damaged_pdf(msg));
+    }
+
+    QPDF& qpdf;
+    InputSource* const& file;
+    QPDFTokenizer tokenizer;
+
+    std::vector<Entry> table;
+    QPDFObjectHandle trailer_;
+
+    bool attempt_recovery_{true};
+    bool initialized_{false};
+    bool ignore_streams_{false};
+    bool reconstructed_{false};
+    bool object_streams_{false};
+    // Before the xref table is initialized, max_id_ is an upper bound on the possible object ids
+    // that could be present in the PDF file. Once the trailer has been read, max_id_ is set to the
+    // value of /Size. If the file is damaged, max_id_ becomes the maximum object id in the xref
+    // table after reconstruction.
+    int max_id_{std::numeric_limits<int>::max() - 1};
+
+    // Linearization data
+    bool uncompressed_after_compressed_{false};
+    qpdf_offset_t first_item_offset_{0}; // actual value from file
+};
+
+// The Resolver class is restricted to QPDFObject so that only it can resolve indirect
+// references.
+class QPDF::Resolver
+{
+    friend class QPDFObject;
+    friend class QPDF_Unresolved;
+
+  private:
+    static QPDFObject*
+    resolved(QPDF* qpdf, QPDFObjGen og)
+    {
+        return qpdf->resolve(og);
+    }
+};
+
 // StreamCopier class is restricted to QPDFObjectHandle so it can copy stream data.
 class QPDF::StreamCopier
 {
@@ -38,7 +406,7 @@ class QPDF::ParseGuard
     static std::shared_ptr<QPDFObject>
     getObject(QPDF* qpdf, int id, int gen, bool parse_pdf)
     {
-        return qpdf->objects().get_for_parser(id, gen, parse_pdf);
+        return qpdf->getObjectForParser(id, gen, parse_pdf);
     }
     ~ParseGuard()
@@ -72,6 +440,19 @@ class QPDF::Pipe
     }
 };
+class QPDF::ObjCache
+{
+  public:
+    ObjCache() = default;
+
+    ObjCache(std::shared_ptr<QPDFObject> object) :
+        object(object)
+    {
+    }
+
+    std::shared_ptr<QPDFObject> object;
+};
+
 class QPDF::ObjCopier
 {
   public:
@@ -369,7 +750,8 @@ class QPDF::Members
     bool check_mode{false};
     std::shared_ptr<EncryptionParameters> encp;
     std::string pdf_version;
-    Objects objects;
+    Xref_table xref_table;
+    std::map<QPDFObjGen, ObjCache> obj_cache;
     std::set<QPDFObjGen> resolving;
     std::vector<QPDFObjectHandle> all_pages;
     bool invalid_page_found{false};
@@ -418,33 +800,6 @@ class QPDF::Members
     std::map<QPDFObjGen, std::set<ObjUser>> object_to_obj_users;
 };
-inline QPDF::Objects&
-QPDF::objects() noexcept
-{
-    return m->objects;
-}
-
-inline QPDF::Objects const&
-QPDF::objects() const noexcept
-{
-    return m->objects;
-}
-
-// The Resolver class is restricted to QPDFObject so that only it can resolve indirect
-// references.
-class QPDF::Resolver
-{
-    friend class QPDFObject;
-    friend class QPDF_Unresolved;
-
-  private:
-    static QPDFObject*
-    resolved(QPDF* qpdf, QPDFObjGen og)
-    {
-        return qpdf->m->objects.resolve(og);
-    }
-};
-
 // JobSetter class is restricted to QPDFJob.
 class QPDF::JobSetter
 {
@@ -521,25 +876,25 @@ class QPDF::Writer
     static std::vector<QPDFObjGen>
     getCompressibleObjGens(QPDF& qpdf)
     {
-        return qpdf.objects().compressible_vector();
+        return qpdf.getCompressibleObjVector();
     }
     static std::vector<bool>
     getCompressibleObjSet(QPDF& qpdf)
     {
-        return qpdf.objects().compressible_set();
+        return qpdf.getCompressibleObjSet();
     }
-    static Objects::Xref_table const&
+    static Xref_table const&
     getXRefTable(QPDF& qpdf)
     {
-        return qpdf.objects().xref_table();
+        return qpdf.m->xref_table;
     }
     static size_t
     tableSize(QPDF& qpdf)
     {
-        return qpdf.objects().table_size();
+        return qpdf.tableSize();
     }
 };