Fix bad indexing error with open splines

thomasp85 · Mar 12, 2019 · 1760568 · 1760568
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diff --git a/NEWS.md b/NEWS.md
@@ -1,5 +1,9 @@
 # ggforce (development version)
 
+- Fixed a bug in the calculation of open and closed b-splines, where the
+  interval would exceed the defined region and result in an out-of-bounds memory
+  error
+
 # ggforce 0.2.0
 
 ## New features

diff --git a/src/bSpline.cpp b/src/bSpline.cpp
@@ -44,7 +44,12 @@ NumericMatrix splinePath(NumericVector x, NumericVector y, int degree, std::vect
     controls.push_back(controls[2]);
   }
   NumericMatrix res(detail, 2);
-  double zJump = (knots[knots.size()-1-degree] - knots[degree]) / double(detail-1);
+  double zJump = (knots[knots.size()-1-degree] - knots[degree]);
+  if (type == "clamped") {
+    zJump /= double(detail-1);
+  } else {
+    zJump /= double(detail);
+  }
   double z;
   Point point;
   for (int i = 0; i < detail; i++) {