Support TIFF Predictor (fixes #171)

6 files changed, 38 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 245b96f2..5c023bd3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2018-01-13  Jay Berkenbilt  <ejb@ql.org>
+
+	* Add support for TIFF predictor for LZW and Flate streams. Now
+	all predictor functions are supported.
+
 2017-12-25  Jay Berkenbilt  <ejb@ql.org>
 
 	* Clarify documentation around options that control parsing but
diff --git a/libqpdf/QPDF_Stream.cc b/libqpdf/QPDF_Stream.cc
index 351df043..89b6b5a9 100644
--- a/libqpdf/QPDF_Stream.cc
+++ b/libqpdf/QPDF_Stream.cc
@@ -4,6 +4,7 @@
 #include <qpdf/Pipeline.hh>
 #include <qpdf/Pl_Flate.hh>
 #include <qpdf/Pl_PNGFilter.hh>
+#include <qpdf/Pl_TIFFPredictor.hh>
 #include <qpdf/Pl_RC4.hh>
 #include <qpdf/Pl_Buffer.hh>
 #include <qpdf/Pl_ASCII85Decoder.hh>
@@ -133,7 +134,7 @@ QPDF_Stream::understandDecodeParams(
             if (predictor_obj.isInteger())
             {
                 predictor = predictor_obj.getIntValue();
-                if (! ((predictor == 1) ||
+                if (! ((predictor == 1) || (predictor == 2) ||
                        ((predictor >= 10) && (predictor <= 15))))
                 {
                     filterable = false;
@@ -459,14 +460,24 @@ QPDF_Stream::pipeStreamData(Pipeline* pipeline,
 	{
 	    std::string const& filter = *iter;
 
-            if (((filter == "/FlateDecode") || (filter == "/LZWDecode")) &&
-                ((predictor >= 10) && (predictor <= 15)))
+            if ((filter == "/FlateDecode") || (filter == "/LZWDecode"))
             {
-                QTC::TC("qpdf", "QPDF_Stream PNG filter");
-                pipeline = new Pl_PNGFilter(
-                    "png decode", pipeline, Pl_PNGFilter::a_decode,
-                    columns, colors, bits_per_component);
-                to_delete.push_back(pipeline);
+                if ((predictor >= 10) && (predictor <= 15))
+                {
+                    QTC::TC("qpdf", "QPDF_Stream PNG filter");
+                    pipeline = new Pl_PNGFilter(
+                        "png decode", pipeline, Pl_PNGFilter::a_decode,
+                        columns, colors, bits_per_component);
+                    to_delete.push_back(pipeline);
+                }
+                else if (predictor == 2)
+                {
+                    QTC::TC("qpdf", "QPDF_Stream TIFF predictor");
+                    pipeline = new Pl_TIFFPredictor(
+                        "tiff decode", pipeline, Pl_TIFFPredictor::a_decode,
+                        columns, colors, bits_per_component);
+                    to_delete.push_back(pipeline);
+                }
             }
 
 	    if (filter == "/Crypt")
diff --git a/qpdf/qpdf.testcov b/qpdf/qpdf.testcov
index a36d9706..fd717783 100644
--- a/qpdf/qpdf.testcov
+++ b/qpdf/qpdf.testcov
@@ -301,3 +301,4 @@ qpdf-c called qpdf_set_decode_level 0
 qpdf-c called qpdf_set_compress_streams 0
 qpdf-c called qpdf_set_preserve_unreferenced_objects 0
 qpdf-c called qpdf_set_newline_before_endstream 0
+QPDF_Stream TIFF predictor 0
diff --git a/qpdf/qtest/qpdf.test b/qpdf/qtest/qpdf.test
index 6c88e098..b6e9905b 100644
--- a/qpdf/qtest/qpdf.test
+++ b/qpdf/qtest/qpdf.test
@@ -240,7 +240,7 @@ foreach my $d (@bug_tests)
 show_ntests();
 # ----------
 $td->notify("--- Miscellaneous Tests ---");
-$n_tests += 86;
+$n_tests += 87;
 
 $td->runtest("qpdf version",
 	     {$td->COMMAND => "qpdf --version"},
@@ -684,6 +684,12 @@ $td->runtest("short /O or /U",
               $td->EXIT_STATUS => 0},
              $td->NORMALIZE_NEWLINES);
 
+$td->runtest("stream with tiff predictor",
+             {$td->COMMAND => "qpdf --check tiff-predictor.pdf"},
+             {$td->FILE => "tiff-predictor.out",
+              $td->EXIT_STATUS => 0},
+             $td->NORMALIZE_NEWLINES);
+
 show_ntests();
 # ----------
 $td->notify("--- Newline before endstream ---");
diff --git a/qpdf/qtest/qpdf/tiff-predictor.out b/qpdf/qtest/qpdf/tiff-predictor.out
new file mode 100644
index 00000000..773af026
--- /dev/null
+++ b/qpdf/qtest/qpdf/tiff-predictor.out
@@ -0,0 +1,6 @@
+checking tiff-predictor.pdf
+PDF Version: 1.5
+File is not encrypted
+File is not linearized
+No syntax or stream encoding errors found; the file may still contain
+errors that qpdf cannot detect
diff --git a/qpdf/qtest/qpdf/tiff-predictor.pdf b/qpdf/qtest/qpdf/tiff-predictor.pdf
new file mode 100644
index 00000000..3b8d8265
--- /dev/null
+++ b/qpdf/qtest/qpdf/tiff-predictor.pdf