6 files changed, 134 insertions, 0 deletions

diff --git a/qpdf/qpdf.cc b/qpdf/qpdf.cc
index 99cfd3a1..65a6de1e 100644
--- a/qpdf/qpdf.cc
+++ b/qpdf/qpdf.cc
@@ -203,6 +203,7 @@ familiar with the PDF file format or who are PDF developers.\n\
 --object-streams=mode     controls handing of object streams\n\
 --ignore-xref-streams     tells qpdf to ignore any cross-reference streams\n\
 --precheck-streams        precheck ability to decode streams\n\
+--preserve-unreferenced   preserve unreferenced objects\n\
 --qdf                     turns on \"QDF mode\" (below)\n\
 --min-version=version     sets the minimum PDF version of the output file\n\
 --force-version=version   forces this to be the PDF version of the output file\n\
@@ -1030,6 +1031,7 @@ int main(int argc, char* argv[])
     bool ignore_xref_streams = false;
     bool qdf_mode = false;
     bool precheck_streams = false;
+    bool preserve_unreferenced_objects = false;
     std::string min_version;
     std::string force_version;
 
@@ -1219,6 +1221,10 @@ int main(int argc, char* argv[])
 	    {
 		precheck_streams = true;
 	    }
+	    else if (strcmp(arg, "preserve-unreferenced") == 0)
+	    {
+		preserve_unreferenced_objects = true;
+	    }
 	    else if (strcmp(arg, "min-version") == 0)
 	    {
 		if (parameter == 0)
@@ -1714,6 +1720,10 @@ int main(int argc, char* argv[])
             {
                 w.setPrecheckStreams(true);
             }
+            if (preserve_unreferenced_objects)
+            {
+                w.setPreserveUnreferencedObjects(true);
+            }
 	    if (normalize_set)
 	    {
 		w.setContentNormalization(normalize);
diff --git a/qpdf/qpdf.testcov b/qpdf/qpdf.testcov
index bf227c7a..c64c63ee 100644
--- a/qpdf/qpdf.testcov
+++ b/qpdf/qpdf.testcov
@@ -280,3 +280,4 @@ QPDFObjectHandle found fake 1
 QPDFObjectHandle no val for last key 0
 QPDF resolve failure to null 0
 QPDFWriter precheck stream 0
+QPDFWriter preserve unreferenced standard 0
diff --git a/qpdf/qtest/qpdf.test b/qpdf/qtest/qpdf.test
index b61882b9..45ed8c46 100644
--- a/qpdf/qtest/qpdf.test
+++ b/qpdf/qtest/qpdf.test
@@ -743,6 +743,24 @@ $td->runtest("check output",
 	     {$td->FILE => "bad-data-precheck.pdf"});
 show_ntests();
 # ----------
+$td->notify("--- Preserve unreferenced objects ---");
+$n_tests += 4;
+
+$td->runtest("drop unused objects",
+	     {$td->COMMAND => "qpdf --static-id unreferenced-objects.pdf a.pdf"},
+	     {$td->STRING => "", $td->EXIT_STATUS => 0});
+$td->runtest("check output",
+	     {$td->FILE => "a.pdf"},
+	     {$td->FILE => "unreferenced-dropped.pdf"});
+$td->runtest("keep unused objects",
+	     {$td->COMMAND => "qpdf --static-id --preserve-unreferenced" .
+                  " unreferenced-objects.pdf a.pdf"},
+	     {$td->STRING => "", $td->EXIT_STATUS => 0});
+$td->runtest("check output",
+	     {$td->FILE => "a.pdf"},
+	     {$td->FILE => "unreferenced-preserved.pdf"});
+show_ntests();
+# ----------
 $td->notify("--- Copy Foreign Objects ---");
 $n_tests += 7;
 
diff --git a/qpdf/qtest/qpdf/unreferenced-dropped.pdf b/qpdf/qtest/qpdf/unreferenced-dropped.pdf
new file mode 100644
index 00000000..071d8d7d
--- /dev/null
+++ b/qpdf/qtest/qpdf/unreferenced-dropped.pdf
diff --git a/qpdf/qtest/qpdf/unreferenced-objects.pdf b/qpdf/qtest/qpdf/unreferenced-objects.pdf
new file mode 100644
index 00000000..a6ea90c8
--- /dev/null
+++ b/qpdf/qtest/qpdf/unreferenced-objects.pdf
@@ -0,0 +1,105 @@
+%PDF-1.3
+%¿÷¢þ
+%QDF-1.0
+
+2 0 obj
+<<
+  /Pages 1 0 R
+  /Type /Catalog
+>>
+endobj
+
+1 0 obj
+<<
+  /Count 1
+  /Kids [
+    3 0 R
+  ]
+  /Type /Pages
+>>
+endobj
+
+%% Page 1
+3 0 obj
+<<
+  /Contents 4 0 R
+  /MediaBox [
+    0
+    0
+    612
+    792
+  ]
+  /Parent 1 0 R
+  /Resources <<
+    /Font <<
+      /F1 6 0 R
+    >>
+    /ProcSet 9 0 R
+  >>
+  /Type /Page
+>>
+endobj
+
+%% Contents for page 1
+4 0 obj
+<<
+  /Length 5 0 R
+>>
+stream
+BT
+  /F1 24 Tf
+  72 720 Td
+  (Potato) Tj
+ET
+endstream
+endobj
+
+5 0 obj
+44
+endobj
+
+6 0 obj
+<<
+  /BaseFont /Helvetica
+  /Encoding /WinAnsiEncoding
+  /Name /F1
+  /Subtype /Type1
+  /Type /Font
+>>
+endobj
+
+7 0 obj
+[ 8 0 R ]
+endobj
+
+8 0 obj
+/Potato
+endobj
+
+9 0 obj
+[
+  /PDF
+  /Text
+]
+endobj
+
+xref
+0 10
+0000000000 65535 f 
+0000000079 00000 n 
+0000000025 00000 n 
+0000000161 00000 n 
+0000000376 00000 n 
+0000000475 00000 n 
+0000000494 00000 n 
+0000000612 00000 n 
+0000000638 00000 n 
+0000000662 00000 n 
+trailer <<
+  /Root 2 0 R
+  /Size 10
+  /ID [<5c2381b459937c988290150df782f1fd><5c2381b459937c988290150df782f1fd>]
+>>
+startxref
+697
+%%EOF
diff --git a/qpdf/qtest/qpdf/unreferenced-preserved.pdf b/qpdf/qtest/qpdf/unreferenced-preserved.pdf
new file mode 100644
index 00000000..b92fff5d
--- /dev/null
+++ b/qpdf/qtest/qpdf/unreferenced-preserved.pdf