Add QPDFWriter::setExtraHeaderText

1 files changed, 30 insertions, 1 deletions

diff --git a/libqpdf/QPDFWriter.cc b/libqpdf/QPDFWriter.cc
index 19ab1359..eb08488a 100644
--- a/libqpdf/QPDFWriter.cc
+++ b/libqpdf/QPDFWriter.cc
@@ -196,6 +196,22 @@ QPDFWriter::forcePDFVersion(std::string const& version)
 }
 
 void
+QPDFWriter::setExtraHeaderText(std::string const& text)
+{
+    this->extra_header_text = text;
+    if ((this->extra_header_text.length() > 0) &&
+        (*(this->extra_header_text.rbegin()) != '\n'))
+    {
+        QTC::TC("qpdf", "QPDFWriter extra header text add newline");
+        this->extra_header_text += "\n";
+    }
+    else
+    {
+        QTC::TC("qpdf", "QPDFWriter extra header text no newline");
+    }
+}
+
+void
 QPDFWriter::setStaticID(bool val)
 {
     this->static_id = val;
@@ -1832,6 +1848,12 @@ QPDFWriter::writeHeader()
     // it really should be treated as binary.
     writeString("\n%\xbf\xf7\xa2\xfe\n");
     writeStringQDF("%QDF-1.0\n\n");
+
+    // Note: do not write extra header text here.  Linearized PDFs
+    // must include the entire linearization parameter dictionary
+    // within the first 1024 characters of the PDF file, so for
+    // linearized files, we have to write extra header text after the
+    // linearization parameter dictionary.
 }
 
 void
@@ -2189,7 +2211,9 @@ QPDFWriter::writeLinearized()
 	// space to write real dictionary.  200 characters is enough
 	// space if all numerical values in the parameter dictionary
 	// that contain offsets are 20 digits long plus a few extra
-	// characters for safety.
+	// characters for safety.  The entire linearization parameter
+	// dictionary must appear within the first 1024 characters of
+	// the file.
 
 	qpdf_offset_t pos = this->pipeline->getCount();
 	openObject(lindict_id);
@@ -2225,6 +2249,10 @@ QPDFWriter::writeLinearized()
 	writePad(spaces);
 	writeString("\n");
 
+        // If the user supplied any additional header text, write it
+        // here after the linearization parameter dictionary.
+        writeString(this->extra_header_text);
+
 	// Part 3: first page cross reference table and trailer.
 
 	qpdf_offset_t first_xref_offset = this->pipeline->getCount();
@@ -2396,6 +2424,7 @@ QPDFWriter::writeStandard()
     // Start writing
 
     writeHeader();
+    writeString(this->extra_header_text);
 
     // Put root first on queue.
     QPDFObjectHandle trailer = pdf.getTrailer();