From 97d78c75ff04e3db7801b6e609ee4f9d2e70c3fd Mon Sep 17 00:00:00 2001
From: m-holger <m-holger@kubitscheck.org>
Date: Mon, 4 Mar 2024 11:19:45 +0000
Subject: [PATCH] In QPDFWriter::writeLinearized use object table obj in call
 to optimize

---
 include/qpdf/QPDF.hh         | 18 +++++++++++
 libqpdf/QPDFWriter.cc        |  2 +-
 libqpdf/QPDF_optimization.cc | 60 ++++++++++++++++++++++++++++++++++++
 3 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index b366b17b..685e3e65 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -727,6 +727,15 @@ class QPDF
         friend class QPDFWriter;
 
       private:
+        static void
+        optimize(
+            QPDF& qpdf,
+            QPDFWriter::ObjTable const& obj,
+            std::function<int(QPDFObjectHandle&)> skip_stream_parameters)
+        {
+            return qpdf.optimize(obj, skip_stream_parameters);
+        }
+
         static void
         getLinearizedParts(
             QPDF& qpdf,
@@ -1095,6 +1104,14 @@ class QPDF
     // For QPDFWriter:
 
     std::map<QPDFObjGen, QPDFXRefEntry> const& getXRefTableInternal();
+    template <typename T>
+    void optimize_internal(
+        T const& object_stream_data,
+        bool allow_changes = true,
+        std::function<int(QPDFObjectHandle&)> skip_stream_parameters = nullptr);
+    void optimize(
+        QPDFWriter::ObjTable const& obj,
+        std::function<int(QPDFObjectHandle&)> skip_stream_parameters);
     size_t tableSize();
 
     // Get lists of all objects in order according to the part of a linearized file that they belong
@@ -1413,6 +1430,7 @@ class QPDF
         QPDFObjGen::set& visited,
         bool top);
     void filterCompressedObjects(std::map<int, int> const& object_stream_data);
+    void filterCompressedObjects(QPDFWriter::ObjTable const& object_stream_data);
 
     // JSON import
     void importJSON(std::shared_ptr<InputSource>, bool must_be_complete);
diff --git a/libqpdf/QPDFWriter.cc b/libqpdf/QPDFWriter.cc
index 2ad4d786..a3fd42f3 100644
--- a/libqpdf/QPDFWriter.cc
+++ b/libqpdf/QPDFWriter.cc
@@ -2576,7 +2576,7 @@ QPDFWriter::writeLinearized()
         }
     };
 
-    m->pdf.optimize(m->object_to_object_stream_no_gen, true, skip_stream_parameters);
+    QPDF::Writer::optimize(m->pdf, m->obj, skip_stream_parameters);
 
     std::vector<QPDFObjectHandle> part4;
     std::vector<QPDFObjectHandle> part6;
diff --git a/libqpdf/QPDF_optimization.cc b/libqpdf/QPDF_optimization.cc
index 91da7564..9f423a3a 100644
--- a/libqpdf/QPDF_optimization.cc
+++ b/libqpdf/QPDF_optimization.cc
@@ -5,6 +5,7 @@
 #include <qpdf/QPDF.hh>
 
 #include <qpdf/QPDFExc.hh>
+#include <qpdf/QPDFWriter_private.hh>
 #include <qpdf/QPDF_Array.hh>
 #include <qpdf/QPDF_Dictionary.hh>
 #include <qpdf/QTC.hh>
@@ -58,6 +59,23 @@ QPDF::optimize(
     std::map<int, int> const& object_stream_data,
     bool allow_changes,
     std::function<int(QPDFObjectHandle&)> skip_stream_parameters)
+{
+    optimize_internal(object_stream_data, allow_changes, skip_stream_parameters);
+}
+
+void
+QPDF::optimize(
+    QPDFWriter::ObjTable const& obj, std::function<int(QPDFObjectHandle&)> skip_stream_parameters)
+{
+    optimize_internal(obj, true, skip_stream_parameters);
+}
+
+template <typename T>
+void
+QPDF::optimize_internal(
+    T const& object_stream_data,
+    bool allow_changes,
+    std::function<int(QPDFObjectHandle&)> skip_stream_parameters)
 {
     if (!m->obj_user_to_objects.empty()) {
         // already optimized
@@ -379,3 +397,45 @@ QPDF::filterCompressedObjects(std::map<int, int> const& object_stream_data)
     m->obj_user_to_objects = t_obj_user_to_objects;
     m->object_to_obj_users = t_object_to_obj_users;
 }
+
+void
+QPDF::filterCompressedObjects(QPDFWriter::ObjTable const& obj)
+{
+    if (obj.getStreamsEmpty()) {
+        return;
+    }
+
+    // Transform object_to_obj_users and obj_user_to_objects so that they refer only to uncompressed
+    // objects.  If something is a user of a compressed object, then it is really a user of the
+    // object stream that contains it.
+
+    std::map<ObjUser, std::set<QPDFObjGen>> t_obj_user_to_objects;
+    std::map<QPDFObjGen, std::set<ObjUser>> t_object_to_obj_users;
+
+    for (auto const& i1: m->obj_user_to_objects) {
+        ObjUser const& ou = i1.first;
+        // Loop over objects.
+        for (auto const& og: i1.second) {
+            if (auto const& i2 = obj[og].object_stream; i2 <= 0) {
+                t_obj_user_to_objects[ou].insert(og);
+            } else {
+                t_obj_user_to_objects[ou].insert(QPDFObjGen(i2, 0));
+            }
+        }
+    }
+
+    for (auto const& i1: m->object_to_obj_users) {
+        QPDFObjGen const& og = i1.first;
+        // Loop over obj_users.
+        for (auto const& ou: i1.second) {
+            if (auto i2 = obj[og].object_stream; i2 <= 0) {
+                t_object_to_obj_users[og].insert(ou);
+            } else {
+                t_object_to_obj_users[QPDFObjGen(i2, 0)].insert(ou);
+            }
+        }
+    }
+
+    m->obj_user_to_objects = t_obj_user_to_objects;
+    m->object_to_obj_users = t_object_to_obj_users;
+}