/* Author:  G. Jungman
 * RCS:     $Id: accel.c,v 1.6 1999/08/30 10:36:00 bjg Exp $
 */
#include <config.h>
#include <stdlib.h>
#include "gsl_interp.h"

gsl_interp_accel *
gsl_interp_accel_new (void)
{
  gsl_interp_accel *a = (gsl_interp_accel *) malloc (sizeof (gsl_interp_accel));
  if (a != 0)
    {
      a->cache = 0;
      a->hit_count = 0;
      a->miss_count = 0;
    }
  return a;
}


size_t
gsl_interp_accel_find (gsl_interp_accel * a, const double xa[], size_t len, double x)
{
  size_t x_index = a->cache;

  if (x < xa[x_index])
    {
      a->miss_count++;
      a->cache = gsl_interp_bsearch (xa, x, 0, x_index);
    }
  else if (x > xa[x_index + 1])
    {
      a->miss_count++;
      a->cache = gsl_interp_bsearch (xa, x, x_index, len - 1);
    }
  else
    {
      a->hit_count++;
    }

  return a->cache;
}


void
gsl_interp_accel_free (gsl_interp_accel * a)
{
  if (a != 0)
    {
      free (a);
    }
}