source: src/utils/scale.c @ cd77c15

/*
   Copyright (C) 2003 Paul Brossier

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include "aubio_priv.h"
#include "fvec.h"
#include "utils/scale.h"

struct _aubio_scale_t {
  smpl_t ilow;
  smpl_t ihig;
  smpl_t olow;
  smpl_t ohig;

  smpl_t scaler;
  smpl_t irange;

  /* not implemented yet : type in/out data
     bool inint;
     bool outint;
     */
};

aubio_scale_t * new_aubio_scale (smpl_t ilow, smpl_t ihig, 
    smpl_t olow, smpl_t ohig) {
  aubio_scale_t * s = AUBIO_NEW(aubio_scale_t);
  aubio_scale_set_limits (s, ilow, ihig, olow, ohig);
  return s;
}

void del_aubio_scale(aubio_scale_t *s) {
  AUBIO_FREE(s);
}

void aubio_scale_set_limits (aubio_scale_t *s, smpl_t ilow, smpl_t ihig,
    smpl_t olow, smpl_t ohig) {
  smpl_t inputrange = ihig - ilow;
  smpl_t outputrange= ohig - olow;
  s->ilow = ilow;
  s->ihig = ihig;
  s->olow = olow;
  s->ohig = ohig;
  if (inputrange == 0) {
    s->scaler = 0.0;
  } else {
    s->scaler = outputrange/inputrange;
    if (inputrange < 0) {
      inputrange = inputrange * -1.0f;
    }
  }
}

void aubio_scale_do (aubio_scale_t *s, fvec_t *input) 
{
  uint_t i, j;
  for (i=0; i < input->channels; i++){
    for (j=0;  j < input->length; j++){
      input->data[i][j] -= s->ilow;
      input->data[i][j] *= s->scaler;
      input->data[i][j] += s->olow;
    }
  }
}