Applying second patch for bug #425557.

(bzr r8768)

2 files changed, 25 insertions, 16 deletions

diff --git a/src/2geom/bezier.h b/src/2geom/bezier.h
index 1fe846935..9e68d93ae 100644
--- a/src/2geom/bezier.h
+++ b/src/2geom/bezier.h
@@ -46,7 +46,7 @@ namespace Geom {
 inline Coord subdivideArr(Coord t, Coord const *v, Coord *left, Coord *right, unsigned order) {
 /*
  *  Bernstein : 
- *	Evaluate a Bernstein function at a particular parameter value
+ *      Evaluate a Bernstein function at a particular parameter value
  *      Fill in control points for resulting sub-curves.
  * 
  */
@@ -236,25 +236,34 @@ public:
     //inline Coord const &operator[](unsigned ix) const { return c_[ix]; }
     inline void setPoint(unsigned ix, double val) { c_[ix] = val; }
 
-    /* This is inelegant, as it uses several extra stores.  I think there might be a way to
-     * evaluate roughly in situ. */
-
+    /**
+    *  The size of the returned vector equals n_derivs+1.
+    */
     std::vector<Coord> valueAndDerivatives(Coord t, unsigned n_derivs) const {
-        std::vector<Coord> val_n_der;
+        /* This is inelegant, as it uses several extra stores.  I think there might be a way to
+         * evaluate roughly in situ. */
+
+         // initialize return vector with zeroes, such that we only need to replace the non-zero derivs
+        std::vector<Coord> val_n_der(n_derivs + 1, Coord(0.0));
+
+        // initialize temp storage variables
         std::valarray<Coord> d_(order()+1);
-        unsigned nn = n_derivs + 1; 	// the size of the result vector equals n_derivs+1 ...
-        if(nn > order())
-            nn = order()+1;		// .. but with a maximum of order() + 1!
-        for(unsigned i = 0; i < size(); i++)
+        for (unsigned i = 0; i < size(); i++) {
             d_[i] = c_[i];
-        val_n_der.resize(nn);
-        for(unsigned di = 0; di < nn; di++) {
+        }
+
+        unsigned nn = n_derivs + 1;
+        if(n_derivs > order()) {
+            nn = order()+1; // only calculate the non zero derivs
+        }
+        for (unsigned di = 0; di < nn; di++) {
             //val_n_der[di] = (subdivideArr(t, &d_[0], NULL, NULL, order() - di));
             val_n_der[di] = bernsteinValueAt(t, &d_[0], order() - di);
-            for(unsigned i = 0; i < order() - di; i++) {
+            for (unsigned i = 0; i < order() - di; i++) {
                 d_[i] = (order()-di)*(d_[i+1] - d_[i]);
             }
         }
+
         return val_n_der;
     }
 
diff --git a/src/2geom/d2.h b/src/2geom/d2.h
index afa00b40d..547d8c658 100644
--- a/src/2geom/d2.h
+++ b/src/2geom/d2.h
@@ -97,10 +97,10 @@ class D2{
     }
     std::vector<Point > valueAndDerivatives(double t, unsigned n) const {
         std::vector<Coord> x = f[X].valueAndDerivatives(t, n),
-                           y = f[Y].valueAndDerivatives(t, n);
-        std::vector<Point> res;
-        for(unsigned i = 0; i <= n; i++) {
-            res.push_back(Point(x[i], y[i]));
+                           y = f[Y].valueAndDerivatives(t, n); // always returns a vector of size n+1
+        std::vector<Point> res(n+1);
+        for (unsigned i = 0; i <= n; i++) {
+            res[i] = Point(x[i], y[i]);
         }
         return res;
     }