Enable finer grained control of stream decoding

This commit adds several API methods that enable control over which
types of filters QPDF will attempt to decode. It also adds support for
/RunLengthDecode and /DCTDecode filters for both encoding and
decoding.

1 files changed, 28 insertions, 6 deletions

diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index a8a7e5a7..105ecad9 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -482,10 +482,10 @@ QPDFObjectHandle::replaceDict(QPDFObjectHandle new_dict)
 }
 
 PointerHolder<Buffer>
-QPDFObjectHandle::getStreamData()
+QPDFObjectHandle::getStreamData(qpdf_stream_decode_level_e level)
 {
     assertStream();
-    return dynamic_cast<QPDF_Stream*>(obj.getPointer())->getStreamData();
+    return dynamic_cast<QPDF_Stream*>(obj.getPointer())->getStreamData(level);
 }
 
 PointerHolder<Buffer>
@@ -496,13 +496,35 @@ QPDFObjectHandle::getRawStreamData()
 }
 
 bool
-QPDFObjectHandle::pipeStreamData(Pipeline* p, bool filter,
-				 bool normalize, bool compress,
+QPDFObjectHandle::pipeStreamData(Pipeline* p,
+                                 unsigned long encode_flags,
+                                 qpdf_stream_decode_level_e decode_level,
                                  bool suppress_warnings)
 {
     assertStream();
     return dynamic_cast<QPDF_Stream*>(obj.getPointer())->pipeStreamData(
-	p, filter, normalize, compress, suppress_warnings);
+	p, encode_flags, decode_level, suppress_warnings);
+}
+
+bool
+QPDFObjectHandle::pipeStreamData(Pipeline* p, bool filter,
+				 bool normalize, bool compress)
+{
+    unsigned long encode_flags = 0;
+    qpdf_stream_decode_level_e decode_level = qpdf_dl_none;
+    if (filter)
+    {
+        decode_level = qpdf_dl_generalized;
+        if (normalize)
+        {
+            encode_flags |= qpdf_ef_normalize;
+        }
+        if (compress)
+        {
+            encode_flags |= qpdf_ef_compress;
+        }
+    }
+    return pipeStreamData(p, encode_flags, decode_level, false);
 }
 
 void
@@ -825,7 +847,7 @@ QPDFObjectHandle::parseContentStream(QPDFObjectHandle stream_or_array,
                 all_description += ",";
             }
             all_description += " " + og;
-            if (! stream.pipeStreamData(&buf, true, false, false, false))
+            if (! stream.pipeStreamData(&buf, 0, qpdf_dl_specialized))
             {
                 QTC::TC("qpdf", "QPDFObjectHandle errors in parsecontent");
                 warn(stream.getOwningQPDF(),