Fix logic for when to compress object and xref streams (fixes #271)

ChangeLog

@@ -1,5 +1,9 @@
 2019-01-28  Jay Berkenbilt  <ejb@ql.org>
 
+	* Bug fix: when using --stream-data=compress, object streams and
+	xref streams were not compressed. They were compressed if no
+	--stream-data option was specified. Fixes #271.
+
 	* When linearizing or getting the list of all pages in a file,
 	replace duplicated page objects with a shallow copy of the page
 	object. Linearization and all page manipulation APIs require page

TODO

@@ -9,10 +9,6 @@ Soon
    latter is appropriate when a page is being converted to a form
    XObject.
 
- * Look at the file for issue 271 (../misc/bugs/271/6059954.pdf) to
-   figure out why the compression is bad and see if I can do anything
-   about it.
-
 Next ABI
 ========
 

libqpdf/QPDFWriter.cc

@@ -1934,7 +1934,9 @@ QPDFWriter::writeObjectStream(QPDFObjectHandle object)
 
 	    // Set up a stream to write the stream data into a buffer.
 	    Pipeline* next = pushPipeline(new Pl_Buffer("object stream"));
-            if (! (this->m->stream_decode_level || this->m->qdf_mode))
+            if ((this->m->compress_streams ||
+                 (this->m->stream_decode_level == qpdf_dl_none)) &&
+                (! this->m->qdf_mode))
 	    {
 		compressed = true;
 		next = pushPipeline(
@@ -2876,7 +2878,9 @@ QPDFWriter::writeXRefStream(int xref_id, int max_id, qpdf_offset_t max_offset,
 
     Pipeline* p = pushPipeline(new Pl_Buffer("xref stream"));
     bool compressed = false;
-    if (! (this->m->stream_decode_level || this->m->qdf_mode))
+    if ((this->m->compress_streams ||
+         (this->m->stream_decode_level == qpdf_dl_none)) &&
+        (! this->m->qdf_mode))
     {
 	compressed = true;
 	if (! skip_compression)

manual/qpdf-manual.xml

@@ -4417,6 +4417,13 @@ print "\n";
           pages tree.
          </para>
         </listitem>
+        <listitem>
+         <para>
+          Using older option <option>--stream-data=compress</option>
+          with object streams, object streams and xref streams were
+          not compressed.
+         </para>
+        </listitem>
        </itemizedlist>
       </listitem>
       <listitem>

qpdf/qtest/qpdf.test

@@ -1435,7 +1435,7 @@ foreach my $d (
                       " $flags streams-with-newlines.pdf a.pdf"},
                  {$td->STRING => "", $td->EXIT_STATUS => 0},
                  $td->NORMALIZE_NEWLINES);
-    $td->runtest("check output",
+    $td->runtest("check output ($description)",
                  {$td->FILE => "a.pdf"},
                  {$td->FILE => "newline-before-endstream-$suffix.pdf"});
     if ($flags =~ /qdf/)
@@ -2461,7 +2461,7 @@ for (my $n = 16; $n <= 19; ++$n)
 show_ntests();
 # ----------
 $td->notify("--- Specific File Tests ---");
-$n_tests += 2;
+$n_tests += 4;
 
 # Special PDF files that caused problems at some point
 
@@ -2473,6 +2473,15 @@ $td->runtest("damaged stream (C)",
 	     {$td->COMMAND => "qpdf-ctest 2 damaged-stream.pdf '' a.pdf"},
 	     {$td->FILE => "damaged-stream-c-check.out", $td->EXIT_STATUS => 0},
 	     $td->NORMALIZE_NEWLINES);
+$td->runtest("compress objstm and xref",
+             {$td->COMMAND =>
+                  "qpdf --static-id --stream-data=compress".
+                  " --object-streams=generate minimal.pdf a.pdf"},
+             {$td->STRING => "", $td->EXIT_STATUS => 0},
+             $td->NORMALIZE_NEWLINES);
+$td->runtest("check output",
+	     {$td->FILE => "a.pdf"},
+	     {$td->FILE => "compress-objstm-xref.pdf"});
 
 show_ntests();
 # ----------