#ifndef dm_sample_H
#define dm_sample_H

/* Encoded of numerical signal samples */
/* Last edited on 2006-12-24 22:43:58 by stolfi */

#define dm_sample_H_COPYRIGHT \
  "Copyright © 2006  by the State University of Campinas (UNICAMP)"

#include <dm_basic.h>

#include <vec.h>

/* This interface defines the type {dm_sample_t}, an encoded 
  sample from a real-valued signal. 
  
  The numbers are encoded as signed bytes in the range {-127..+127}, 
  using a non-linear encoding. The encoding is designed to map
  a normal-distributed variable to a uniformly distributed code 
  in that range. */
  
typedef signed char dm_sample_t; 
  /* One coordinate of a sample, packed as a character. */

#define dm_sample_VALID_MIN (-127)
#define dm_sample_VALID_MAX (+127)
  /* Minimum and maximum valid values of a {dm_sample_t}. */

double dm_sample_decode(dm_sample_t ev);
dm_sample_t dm_sample_encode(double dv);
  /* Converts between unpacked ({double}) and packed ({dm_sample_t}) 
    representations of sample values.   */

double dm_sample_diffsq(dm_sample_t xs, dm_sample_t ys);
  /* Returns the abs difference squared between the samples,
    defined as {(dm_sample_decode(xs) - dm_sample_decode(ys))^2}. */

vec_typedef(dm_sample_vec_t,dm_sample_vec,dm_sample_t);
/* Vector of {dm_sample_t}. */

#endif