From 99df15a5fff7fd6ac0f64b781d34cb2b2a4bc706 Mon Sep 17 00:00:00 2001
From: Matthias Koefferlein <matthias@klayout.de>
Date: Sat, 22 Jul 2023 18:14:14 +0200
Subject: [PATCH] Update on issue 1422 fix - fixing an array index out of
 bounds issue; do no use control points for first and last point as splines
 may not be designed to terminate at those.

---
 src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc | 10 +++++-----
 .../streamers/dxf/unit_tests/dbDXFReaderTests.cc   | 14 +++++++++++++-
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc b/src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc
index 2f5bacb89..54a6c0e28 100644
--- a/src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc
+++ b/src/plugins/streamers/dxf/db_plugin/dbDXFReader.cc
@@ -817,12 +817,12 @@ 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, int &k)
 {
   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;
-  }
   --k;
+  if (k < p) {
+    k = p;
+  } else if (k >= (int) control_points.size ()) {
+    k = (int) control_points.size () - 1;
+  }
 
   std::vector<db::DPoint> d;
   std::vector<double> dw;
diff --git a/src/plugins/streamers/dxf/unit_tests/dbDXFReaderTests.cc b/src/plugins/streamers/dxf/unit_tests/dbDXFReaderTests.cc
index a9e7d9c7b..265e4bdff 100644
--- a/src/plugins/streamers/dxf/unit_tests/dbDXFReaderTests.cc
+++ b/src/plugins/streamers/dxf/unit_tests/dbDXFReaderTests.cc
@@ -517,10 +517,22 @@ TEST(34)
 }
 
 //  issue #1422
-TEST(35)
+TEST(35a)
 {
   db::DXFReaderOptions opt;
   run_test_public (_this, "issue_1422a.dxf", "issue_1422a_au.gds.gz", opt);
+}
+
+//  issue #1422
+TEST(35b)
+{
+  db::DXFReaderOptions opt;
   run_test_public (_this, "issue_1422b.dxf", "issue_1422b_au.gds.gz", opt);
+}
+
+//  issue #1422
+TEST(35c)
+{
+  db::DXFReaderOptions opt;
   run_test_public (_this, "issue_1422c.dxf", "issue_1422c_au.gds.gz", opt);
 }