text: /* Copyright (c) 2002-2003 krzYszcz and others.
   * For information on usage and redistribution, and for a DISCLAIMER OF ALL
   * WARRANTIES, see the file, "LICENSE.txt," in this distribution.  */
  
  #include "m_pd.h"
  #include <common/api.h>
  
  typedef struct _delta
  {
      t_object x_obj;
      t_inlet *delta;
      t_outlet *x_outlet;
      t_float  x_last;
  } t_delta;
  
  static t_class *delta_class;
  
  static t_int *delta_perform(t_int *w)
  {
      t_delta *x = (t_delta *)(w[1]);
      int nblock = (int)(w[2]);
      t_float *in = (t_float *)(w[3]);
      t_float *out = (t_float *)(w[4]);
      t_float last = x->x_last;
      while (nblock--)
      {
  	t_float f = *in++;
      	*out++ = f - last;
  	last = f;
      }
      x->x_last = last;
      return (w + 5);
  }
  
  static void delta_dsp(t_delta *x, t_signal **sp)
  {
      dsp_add(delta_perform, 4, x, sp[0]->s_n, sp[0]->s_vec, sp[1]->s_vec);
  }
  
  static void *delta_new(void)
  {
      t_delta *x = (t_delta *)pd_new(delta_class);
      x->x_outlet = outlet_new(&x->x_obj, &s_signal);
      x->x_last = 0;
      return (x);
  }
  
  CYCLONE_OBJ_API void delta_tilde_setup(void)
  {
      delta_class = class_new(gensym("delta~"),
  			    (t_newmethod)delta_new, 0,
  			    sizeof(t_delta), CLASS_DEFAULT, 0);
      class_addmethod(delta_class, nullfn, gensym("signal"), 0);
      class_addmethod(delta_class, (t_method) delta_dsp, gensym("dsp"), A_CANT, 0);
  }
  