Add tests for new PNG filters

libqpdf/Pl_PNGFilter.cc

@@ -1,4 +1,5 @@
 #include <qpdf/Pl_PNGFilter.hh>
+#include <qpdf/QTC.hh>
 #include <stdexcept>
 #include <string.h>
 #include <limits.h>
@@ -134,6 +135,7 @@ Pl_PNGFilter::decodeRow()
 void
 Pl_PNGFilter::decodeSub()
 {
+    QTC::TC("libtests", "Pl_PNGFilter decodeSub");
     unsigned char* buffer = this->cur_row + 1;
     unsigned int bpp = this->bytes_per_pixel;
 
@@ -153,6 +155,7 @@ Pl_PNGFilter::decodeSub()
 void
 Pl_PNGFilter::decodeUp()
 {
+    QTC::TC("libtests", "Pl_PNGFilter decodeUp");
     unsigned char* buffer = this->cur_row + 1;
     unsigned char* above_buffer = this->prev_row + 1;
 
@@ -166,6 +169,7 @@ Pl_PNGFilter::decodeUp()
 void
 Pl_PNGFilter::decodeAverage()
 {
+    QTC::TC("libtests", "Pl_PNGFilter decodeAverage");
     unsigned char* buffer = this->cur_row + 1;
     unsigned char* above_buffer = this->prev_row + 1;
     unsigned int bpp = this->bytes_per_pixel;
@@ -188,6 +192,7 @@ Pl_PNGFilter::decodeAverage()
 void
 Pl_PNGFilter::decodePaeth()
 {
+    QTC::TC("libtests", "Pl_PNGFilter decodePaeth");
     unsigned char* buffer = this->cur_row + 1;
     unsigned char* above_buffer = this->prev_row + 1;
     unsigned int bpp = this->bytes_per_pixel;

libtests/libtests.testcov

@@ -29,3 +29,7 @@ Pl_RunLength flush full buffer 1
 Pl_RunLength flush empty buffer 0
 Pl_DCT empty_pipeline_output_buffer 0
 Pl_DCT term_pipeline_destination 0
+Pl_PNGFilter decodeSub 0
+Pl_PNGFilter decodeUp 0
+Pl_PNGFilter decodeAverage 0
+Pl_PNGFilter decodePaeth 0

libtests/png_filter.cc

@@ -8,7 +8,8 @@
 #include <string.h>
 #include <stdlib.h>
 
-void run(char const* filename, bool encode, unsigned int columns)
+void run(char const* filename, bool encode, unsigned int columns,
+         int bits_per_sample, int samples_per_pixel)
 {
     // Decode the file
     FILE* in = QUtil::safe_fopen(filename, "rb");
@@ -17,7 +18,7 @@ void run(char const* filename, bool encode, unsigned int columns)
     Pipeline* pl = new Pl_PNGFilter(
 	"png", out,
 	encode ? Pl_PNGFilter::a_encode : Pl_PNGFilter::a_decode,
-	columns);
+	columns, samples_per_pixel, bits_per_sample);
     assert((2 * (columns + 1)) < 1024);
     unsigned char buf[1024];
     size_t len;
@@ -54,18 +55,22 @@ void run(char const* filename, bool encode, unsigned int columns)
 
 int main(int argc, char* argv[])
 {
-    if (argc != 4)
+    if (argc != 6)
     {
-	std::cerr << "Usage: pipeline {en,de}code filename columns" << std::endl;
+	std::cerr << "Usage: png_filter {en,de}code filename"
+                  << " columns samples-per-pixel bits-per-sample"
+                  << std::endl;
 	exit(2);
     }
     bool encode = (strcmp(argv[1], "encode") == 0);
     char* filename = argv[2];
     int columns = QUtil::string_to_int(argv[3]);
+    int samples_per_pixel = QUtil::string_to_int(argv[4]);
+    int bits_per_sample = QUtil::string_to_int(argv[5]);
 
     try
     {
-	run(filename, encode, columns);
+	run(filename, encode, columns, bits_per_sample, samples_per_pixel);
     }
     catch (std::exception& e)
     {

libtests/qtest/png_filter.test

@@ -14,7 +14,7 @@ my $td = new TestDriver('png_filter');
 cleanup();
 
 $td->runtest("decode columns = 4",
-	     {$td->COMMAND => "png_filter decode in1 4"},
+	     {$td->COMMAND => "png_filter decode in1 4 1 8"},
 	     {$td->STRING => "done\n",
 	      $td->EXIT_STATUS => 0},
 	     $td->NORMALIZE_NEWLINES);
@@ -24,7 +24,7 @@ $td->runtest("check output",
 	     {$td->FILE => "out1"});
 
 $td->runtest("decode columns = 5",
-	     {$td->COMMAND => "png_filter decode in2 5"},
+	     {$td->COMMAND => "png_filter decode in2 5 1 8"},
 	     {$td->STRING => "done\n",
 	      $td->EXIT_STATUS => 0},
 	     $td->NORMALIZE_NEWLINES);
@@ -34,7 +34,7 @@ $td->runtest("check output",
 	     {$td->FILE => "out2"});
 
 $td->runtest("encode columns = 4",
-	     {$td->COMMAND => "png_filter encode out1 4"},
+	     {$td->COMMAND => "png_filter encode out1 4 1 8"},
 	     {$td->STRING => "done\n",
 	      $td->EXIT_STATUS => 0},
 	     $td->NORMALIZE_NEWLINES);
@@ -44,7 +44,7 @@ $td->runtest("check output",
 	     {$td->FILE => "in1"});
 
 $td->runtest("encode columns = 5",
-	     {$td->COMMAND => "png_filter encode out2 5"},
+	     {$td->COMMAND => "png_filter encode out2 5 1 8"},
 	     {$td->STRING => "done\n",
 	      $td->EXIT_STATUS => 0},
 	     $td->NORMALIZE_NEWLINES);
@@ -53,9 +53,41 @@ $td->runtest("check output",
 	     {$td->FILE => "out"},
 	     {$td->FILE => "in2"});
 
+my @other = (
+    '01--32-3-16',
+    '02--32-1-8',
+    '03--32-3-8',
+    '04--32-1-8',
+    '05--32-3-8',
+    '06--32-1-8',
+    '07--32-3-8',
+    '08--32-1-8',
+    '09--32-3-8',
+    '10--32-1-8',
+    '11--32-3-8',
+    '12--32-1-4',
+    );
+
+foreach my $i (@other)
+{
+    $i =~ m/^.*?--(\d+)-(\d+)-(\d+)$/ or die;
+    my $columns = $1;
+    my $samples_per_pixel = $2;
+    my $bits_per_sample = $3;
+    $td->runtest("decode $i",
+                 {$td->COMMAND => "png_filter decode $i.data" .
+                      " $columns $samples_per_pixel $bits_per_sample"},
+                 {$td->STRING => "done\n",
+                      $td->EXIT_STATUS => 0},
+                 $td->NORMALIZE_NEWLINES);
+    $td->runtest("check output for $i",
+                 {$td->FILE => "out"},
+                 {$td->FILE => "$i.decoded"});
+}
+
 cleanup();
 
-$td->report(8);
+$td->report(8 + (2 * scalar(@other)));
 
 sub cleanup
 {

qpdf/qtest/qpdf.test

@@ -2335,6 +2335,29 @@ $td->runtest("convert inline-images to qdf",
 
 compare_pdfs("inline-images.pdf", "a.pdf");
 
+show_ntests();
+
+
+# ----------
+$td->notify("--- PNG filtering Tests ---");
+$n_tests += 2;
+$n_compare_pdfs += 1;
+
+# The PDF file was submitted on bug #83 on github. All the PNG filters
+# are exercised. The test suite does not exercise PNG predictors with
+# LZW because I don't have a way to create such a file, but it's very
+# likely that it will work since the handling of the PNG filters is
+# separate from the regular decompression.
+$td->runtest("decode png-filtering",
+	     {$td->COMMAND => "qpdf --static-id" .
+                  " --compress-streams=n --decode-level=generalized" .
+		  " png-filters.pdf a.pdf"},
+	     {$td->STRING => "", $td->EXIT_STATUS => 0});
+$td->runtest("check output",
+	     {$td->FILE => "a.pdf"},
+	     {$td->FILE => "png-filters-decoded.pdf"});
+compare_pdfs("png-filters.pdf", "a.pdf");
+
 show_ntests();
 # ----------
 $td->notify("--- fix-qdf Tests ---");