Fixed issue-1422 (DXF file parsing error)

Problem were two spline interpolation issues:
1. wrong stop criterion for recursion
2. wrong implementation of single-point interpolation

src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc

@@ -814,10 +814,10 @@ De Boor algorithm for NURBS
 */
 
 static db::DPoint
-b_spline_point (double x, const std::vector<std::pair<db::DPoint, double> > &control_points, int p, const std::vector<double> &t)
+b_spline_point (double x, const std::vector<std::pair<db::DPoint, double> > &control_points, int p, const std::vector<double> &t, int &k)
 {
-  int k = (int) (std::lower_bound (t.begin (), t.end (), x + 1e-6) - t.begin ());
-  if (k <= p) {
+  k = (int) (std::lower_bound (t.begin (), t.end (), x - 1e-6) - t.begin ());
+  if (k < p) {
     return control_points.front ().first;
   } else if (k > (int) control_points.size ()) {
     return control_points.back ().first;
@@ -878,14 +878,16 @@ spline_interpolate (std::list<db::DPoint> &curve_points,
   std::list<db::DPoint>::iterator pe = pm;
   ++pe;
 
-  db::DPoint s1 = b_spline_point (t_start + 0.5 * dt, control_points, degree, knots);
-  db::DPoint s2 = b_spline_point (t_start + 1.5 * dt, control_points, degree, knots);
+  int k1 = 0, k2 = 0;
+
+  db::DPoint s1 = b_spline_point (t_start + 0.5 * dt, control_points, degree, knots, k1);
+  db::DPoint s2 = b_spline_point (t_start + 1.5 * dt, control_points, degree, knots, k2);
 
   db::DVector p1 (s1, *current_curve_point);
   db::DVector p2 (*pm, s1);
   double pl1 = p1.length(), pl2 = p2.length();
 
-  if (curve_points.size () < control_points.size () - degree - 1) {
+  if (k1 != k2) {
 
     curve_points.insert (pm, s1);
     spline_interpolate (curve_points, current_curve_point, t_start, dt * 0.5, control_points, degree, knots, sin_da, accu);
@@ -958,12 +960,12 @@ DXFReader::spline_interpolation (std::vector<std::pair<db::DPoint, double> > &co
   double accu = std::max (m_circle_accuracy, m_dbu / m_unit);
 
   std::list<db::DPoint> new_points;
-  new_points.push_back (control_points.front ().first);
 
   double dt = 0.5 * (tn - t0);
 
-  for (double t = t0 + dt; t < tn + 1e-6; t += dt) {
-    db::DPoint s = b_spline_point (t, control_points, degree, knots);
+  for (double t = t0; t < tn + 1e-6; t += dt) {
+    int k = 0;
+    db::DPoint s = b_spline_point (t, control_points, degree, knots, k);
     new_points.push_back (s);
   }
 

src/plugins/streamers/dxf/unit_tests/dbDXFReaderTests.cc

@@ -182,7 +182,7 @@ TEST(15)
   db::DXFReaderOptions opt;
   opt.layer_map = string2lm ("TEXT:4,IGBT:5,Wire:7,Ceramic:11,LAYER_1:14,Diode:18,'DBC TOP Plate':19,'Terminal Position':20");
   opt.create_other_layers = true;
-  run_test (_this, "t15.dxf.gz", "t15_au2.gds.gz", opt);
+  run_test (_this, "t15.dxf.gz", "t15_au2_2.gds.gz", opt);
 }
 
 TEST(16)
@@ -190,7 +190,7 @@ TEST(16)
   db::DXFReaderOptions opt;
   opt.layer_map = string2lm ("TEXT:4,IGBT:5,Wire:7,Ceramic:11,LAYER_1:14,Diode:18,'DBC TOP Plate':19,'Terminal Position':20");
   opt.create_other_layers = true;
-  run_test (_this, "t16.dxf.gz", "t16_au2.gds.gz", opt);
+  run_test (_this, "t16.dxf.gz", "t16_au2_2.gds.gz", opt);
 }
 
 TEST(17)
@@ -198,7 +198,7 @@ TEST(17)
   db::DXFReaderOptions opt;
   opt.layer_map = string2lm ("TEXT:4,IGBT:5,Wire:7,Ceramic:11,LAYER_1:14,Diode:18,'DBC TOP Plate':19,'Terminal Position':20");
   opt.create_other_layers = true;
-  run_test (_this, "t17.dxf.gz", "t17_au2.gds.gz", opt);
+  run_test (_this, "t17.dxf.gz", "t17_au2_2.gds.gz", opt);
 }
 
 TEST(18)
@@ -515,3 +515,12 @@ TEST(34)
 
   run_test_public (_this, "issue_1173.dxf", "issue_1173_au.gds.gz", opt);
 }
+
+//  issue #1422
+TEST(35)
+{
+  db::DXFReaderOptions opt;
+  run_test_public (_this, "issue_1422a.dxf", "issue_1422a_au.gds.gz", opt);
+  run_test_public (_this, "issue_1422b.dxf", "issue_1422b_au.gds.gz", opt);
+  run_test_public (_this, "issue_1422c.dxf", "issue_1422c_au.gds.gz", opt);
+}