From 12ecd2019a3186d11ebb6083b3813ce722fb2329 Mon Sep 17 00:00:00 2001
From: Jay Berkenbilt <ejb@ql.org>
Date: Sat, 26 Dec 2020 19:45:01 -0500
Subject: Add QPDFObjectHandle::setFilterOnWrite

---
 libqpdf/QPDFObjectHandle.cc | 14 ++++++++++++++
 libqpdf/QPDFWriter.cc       | 15 +++++++++++----
 libqpdf/QPDF_Stream.cc      | 13 +++++++++++++
 libqpdf/qpdf/QPDF_Stream.hh |  3 +++
 4 files changed, 41 insertions(+), 4 deletions(-)

(limited to 'libqpdf')

diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index e09146e4..7b36fffe 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -1176,6 +1176,20 @@ QPDFObjectHandle::getDict()
     return dynamic_cast<QPDF_Stream*>(obj.getPointer())->getDict();
 }
 
+void
+QPDFObjectHandle::setFilterOnWrite(bool val)
+{
+    assertStream();
+    dynamic_cast<QPDF_Stream*>(obj.getPointer())->setFilterOnWrite(val);
+}
+
+bool
+QPDFObjectHandle::getFilterOnWrite()
+{
+    assertStream();
+    return dynamic_cast<QPDF_Stream*>(obj.getPointer())->getFilterOnWrite();
+}
+
 bool
 QPDFObjectHandle::isDataModified()
 {
diff --git a/libqpdf/QPDFWriter.cc b/libqpdf/QPDFWriter.cc
index 7057930b..689fef74 100644
--- a/libqpdf/QPDFWriter.cc
+++ b/libqpdf/QPDFWriter.cc
@@ -1470,6 +1470,7 @@ QPDFWriter::willFilterStream(QPDFObjectHandle stream,
 {
     compress_stream = false;
     is_metadata = false;
+
     QPDFObjGen old_og = stream.getObjGen();
     QPDFObjectHandle stream_dict = stream.getDict();
 
@@ -1481,7 +1482,13 @@ QPDFWriter::willFilterStream(QPDFObjectHandle stream,
     bool filter = (stream.isDataModified() ||
                    this->m->compress_streams ||
                    this->m->stream_decode_level);
-    if (this->m->compress_streams)
+    bool filter_on_write = stream.getFilterOnWrite();
+    if (! filter_on_write)
+    {
+        QTC::TC("qpdf", "QPDFWriter getFilterOnWrite false");
+        filter = false;
+    }
+    if (filter_on_write && this->m->compress_streams)
     {
         // Don't filter if the stream is already compressed with
         // FlateDecode. This way we don't make it worse if the
@@ -1502,7 +1509,7 @@ QPDFWriter::willFilterStream(QPDFObjectHandle stream,
     }
     bool normalize = false;
     bool uncompress = false;
-    if (is_metadata &&
+    if (filter_on_write && is_metadata &&
         ((! this->m->encrypted) || (this->m->encrypt_metadata == false)))
     {
         QTC::TC("qpdf", "QPDFWriter not compressing metadata");
@@ -1510,13 +1517,13 @@ QPDFWriter::willFilterStream(QPDFObjectHandle stream,
         compress_stream = false;
         uncompress = true;
     }
-    else if (this->m->normalize_content &&
+    else if (filter_on_write && this->m->normalize_content &&
              this->m->normalized_streams.count(old_og))
     {
         normalize = true;
         filter = true;
     }
-    else if (filter && this->m->compress_streams)
+    else if (filter_on_write && filter && this->m->compress_streams)
     {
         compress_stream = true;
         QTC::TC("qpdf", "QPDFWriter compressing uncompressed stream");
diff --git a/libqpdf/QPDF_Stream.cc b/libqpdf/QPDF_Stream.cc
index 8f9b4b52..05cde8d8 100644
--- a/libqpdf/QPDF_Stream.cc
+++ b/libqpdf/QPDF_Stream.cc
@@ -90,6 +90,7 @@ QPDF_Stream::QPDF_Stream(QPDF* qpdf, int objid, int generation,
     qpdf(qpdf),
     objid(objid),
     generation(generation),
+    filter_on_write(true),
     stream_dict(stream_dict),
     offset(offset),
     length(length)
@@ -115,6 +116,18 @@ QPDF_Stream::registerStreamFilter(
     filter_factories[filter_name] = factory;
 }
 
+void
+QPDF_Stream::setFilterOnWrite(bool val)
+{
+    this->filter_on_write = val;
+}
+
+bool
+QPDF_Stream::getFilterOnWrite() const
+{
+    return this->filter_on_write;
+}
+
 void
 QPDF_Stream::releaseResolved()
 {
diff --git a/libqpdf/qpdf/QPDF_Stream.hh b/libqpdf/qpdf/QPDF_Stream.hh
index b11de6a2..c4fdd379 100644
--- a/libqpdf/qpdf/QPDF_Stream.hh
+++ b/libqpdf/qpdf/QPDF_Stream.hh
@@ -27,6 +27,8 @@ class QPDF_Stream: public QPDFObject
     virtual void setDescription(QPDF*, std::string const&);
     QPDFObjectHandle getDict() const;
     bool isDataModified() const;
+    void setFilterOnWrite(bool);
+    bool getFilterOnWrite() const;
 
     // Methods to help QPDF copy foreign streams
     qpdf_offset_t getOffset() const;
@@ -83,6 +85,7 @@ class QPDF_Stream: public QPDFObject
     QPDF* qpdf;
     int objid;
     int generation;
+    bool filter_on_write;
     QPDFObjectHandle stream_dict;
     qpdf_offset_t offset;
     size_t length;
-- 
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