interpolation.cc/h: Fix crash bug and introduce add simple cubic interpolation

git-svn-id: svn://localhost/ardour2/branches/3.0@5418 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 16 insertions, 1 deletions

diff --git a/libs/ardour/ardour/interpolation.h b/libs/ardour/ardour/interpolation.h
index f417c8c46e..1ba2b5a11e 100644
--- a/libs/ardour/ardour/interpolation.h
+++ b/libs/ardour/ardour/interpolation.h
@@ -32,7 +32,7 @@ class Interpolation {
      void remove_channel_from () { phase.pop_back (); }
 
      void reset () {
-         for (size_t i = 0; i <= phase.size(); i++) {
+         for (size_t i = 0; i < phase.size(); i++) {
               phase[i] = 0.0;
           }
      }
@@ -89,6 +89,21 @@ class LinearInterpolation : public Interpolation {
  public:
      nframes_t interpolate (int channel, nframes_t nframes, Sample* input, Sample* output);
 };
+
+class CubicInterpolation : public Interpolation {
+ protected:
+    // shamelessly ripped from Steve Harris' swh-plugins
+    static inline float cube_interp(const float fr, const float inm1, const float
+                                    in, const float inp1, const float inp2)
+    {
+        return in + 0.5f * fr * (inp1 - inm1 +
+         fr * (4.0f * inp1 + 2.0f * inm1 - 5.0f * in - inp2 +
+         fr * (3.0f * (in - inp1) - inm1 + inp2)));
+    }
+    
+ public:
+     nframes_t interpolate (int channel, nframes_t nframes, Sample* input, Sample* output);
+};
  
 
 /**