Bug fix: don't compress hint streams when --compress-streams=n

ChangeLog

@@ -1,7 +1,7 @@
 2023-12-20  Jay Berkenbilt  <ejb@ql.org>
 
-	* Bug fix: with --compress-streams=n, don't compress object or
+	* Bug fix: with --compress-streams=n, don't compress object, XRef,
-	XRef streams.
+	or linearization hint streams.
 
 2023-12-16  Jay Berkenbilt  <ejb@ql.org>
 

include/qpdf/QPDF.hh

@@ -745,9 +745,10 @@ class QPDF
             std::map<int, int> const& obj_renumber,
             std::shared_ptr<Buffer>& hint_stream,
             int& S,
-            int& O)
+            int& O,
+            bool compressed)
         {
-            return qpdf.generateHintStream(xref, lengths, obj_renumber, hint_stream, S, O);
+            return qpdf.generateHintStream(xref, lengths, obj_renumber, hint_stream, S, O, compressed);
         }
 
         static void
@@ -1094,7 +1095,8 @@ class QPDF
         std::map<int, int> const& obj_renumber,
         std::shared_ptr<Buffer>& hint_stream,
         int& S,
-        int& O);
+        int& O,
+        bool compressed);
 
     // Map object to object stream that contains it
     void getObjectStreamData(std::map<int, int>&);

libqpdf/QPDFWriter.cc

@@ -2289,15 +2289,20 @@ QPDFWriter::writeHintStream(int hint_id)
     std::shared_ptr<Buffer> hint_buffer;
     int S = 0;
     int O = 0;
+    bool compressed = (m->compress_streams && !m->qdf_mode);
     QPDF::Writer::generateHintStream(
-        m->pdf, m->xref, m->lengths, m->obj_renumber_no_gen, hint_buffer, S, O);
+        m->pdf, m->xref, m->lengths, m->obj_renumber_no_gen, hint_buffer, S, O, compressed);
 
     openObject(hint_id);
     setDataKey(hint_id);
 
     size_t hlen = hint_buffer->getSize();
 
-    writeString("<< /Filter /FlateDecode /S ");
+    writeString("<< ");
+    if (compressed) {
+        writeString("/Filter /FlateDecode ");
+    }
+    writeString("/S ");
     writeString(std::to_string(S));
     if (O) {
         writeString(" /O ");

libqpdf/QPDF_linearization.cc

@@ -1748,10 +1748,10 @@ QPDF::writeHSharedObject(BitWriter& w)
 void
 QPDF::writeHGeneric(BitWriter& w, HGeneric& t)
 {
-    w.writeBitsInt(t.first_object, 32);             // 1
+    w.writeBitsInt(t.first_object, 32);            // 1
-    w.writeBits(toULL(t.first_object_offset), 32);  // 2
+    w.writeBits(toULL(t.first_object_offset), 32); // 2
-    w.writeBitsInt(t.nobjects, 32);                 // 3
+    w.writeBitsInt(t.nobjects, 32);                // 3
-    w.writeBitsInt(t.group_length, 32);             // 4
+    w.writeBitsInt(t.group_length, 32);            // 4
 }
 
 void
@@ -1761,7 +1761,8 @@ QPDF::generateHintStream(
     std::map<int, int> const& obj_renumber,
     std::shared_ptr<Buffer>& hint_buffer,
     int& S,
-    int& O)
+    int& O,
+    bool compressed)
 {
     // Populate actual hint table values
     calculateHPageOffset(xref, lengths, obj_renumber);
@@ -1771,8 +1772,14 @@ QPDF::generateHintStream(
     // Write the hint stream itself into a compressed memory buffer. Write through a counter so we
     // can get offsets.
     Pl_Buffer hint_stream("hint stream");
-    Pl_Flate f("compress hint stream", &hint_stream, Pl_Flate::a_deflate);
+    Pipeline* next = &hint_stream;
-    Pl_Count c("count", &f);
+    std::shared_ptr<Pipeline> flate;
+    if (compressed) {
+        flate =
+            std::make_shared<Pl_Flate>("compress hint stream", &hint_stream, Pl_Flate::a_deflate);
+        next = flate.get();
+    }
+    Pl_Count c("count", next);
     BitWriter w(&c);
 
     writeHPageOffset(w);