Add precheck streams capability

When requested, QPDFWriter will do more aggress prechecking of streams
to make sure it can actually succeed in decoding them before
attempting to do so. This will allow preservation of raw data even
when the raw data is corrupted relative to the specified filters.

1 files changed, 11 insertions, 6 deletions

diff --git a/libqpdf/QPDF_Stream.cc b/libqpdf/QPDF_Stream.cc
index b4d14441..31d583b8 100644
--- a/libqpdf/QPDF_Stream.cc
+++ b/libqpdf/QPDF_Stream.cc
@@ -85,7 +85,7 @@ PointerHolder<Buffer>
 QPDF_Stream::getStreamData()
 {
     Pl_Buffer buf("stream data buffer");
-    if (! pipeStreamData(&buf, true, false, false))
+    if (! pipeStreamData(&buf, true, false, false, false))
     {
 	throw std::logic_error("getStreamData called on unfilterable stream");
     }
@@ -97,7 +97,7 @@ PointerHolder<Buffer>
 QPDF_Stream::getRawStreamData()
 {
     Pl_Buffer buf("stream data buffer");
-    pipeStreamData(&buf, false, false, false);
+    pipeStreamData(&buf, false, false, false, false);
     QTC::TC("qpdf", "QPDF_Stream getRawStreamData");
     return buf.getBuffer();
 }
@@ -351,7 +351,8 @@ QPDF_Stream::filterable(std::vector<std::string>& filters,
 
 bool
 QPDF_Stream::pipeStreamData(Pipeline* pipeline, bool filter,
-			    bool normalize, bool compress)
+			    bool normalize, bool compress,
+                            bool suppress_warnings)
 {
     std::vector<std::string> filters;
     int predictor = 1;
@@ -487,9 +488,13 @@ QPDF_Stream::pipeStreamData(Pipeline* pipeline, bool filter,
     else
     {
 	QTC::TC("qpdf", "QPDF_Stream pipe original stream data");
-	QPDF::Pipe::pipeStreamData(this->qpdf, this->objid, this->generation,
-				   this->offset, this->length,
-				   this->stream_dict, pipeline);
+	if (! QPDF::Pipe::pipeStreamData(this->qpdf, this->objid, this->generation,
+                                         this->offset, this->length,
+                                         this->stream_dict, pipeline,
+                                         suppress_warnings))
+        {
+            filter = false;
+        }
     }
 
     return filter;