rtbuf/rtbuf/rtbuf_signal_delay.c

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• Hash : 2efd0bc1
  Author : Thomas de Grivel
  Date : 2020-02-01T14:28:08
  

  constant time delay
  

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• rtbuf_signal_delay.c

• /*
   * Copyright 2018 Thomas de Grivel <thoxdg@gmail.com> +33614550127
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  #include <stdio.h>
  #include <strings.h>
  #include "rtbuf.h"
  #include "rtbuf_signal.h"
  
  int rtbuf_signal_delay_start (s_rtbuf *rtb)
  {
    s_rtbuf_signal_delay_data *data;
    assert(rtb->proc->out_bytes == sizeof(*data));
    data = (s_rtbuf_signal_delay_data*) rtb->data;
    bzero(data->in, sizeof(data->in));
    data->pos = 0;
    return 0;
  }
  
  int rtbuf_signal_delay (s_rtbuf *rtb)
  {
    s_rtbuf_signal_fun in;
    s_rtbuf_signal_fun delay;
    s_rtbuf_signal_fun feedback;
    s_rtbuf_signal_delay_data *data;
    unsigned int i = 0;
    rtbuf_signal_fun(rtb, RTBUF_SIGNAL_DELAY_IN_SIGNAL, &in);
    rtbuf_signal_fun(rtb, RTBUF_SIGNAL_DELAY_IN_DELAY, &delay);
    rtbuf_signal_fun(rtb, RTBUF_SIGNAL_DELAY_IN_DELAY, &feedback);
    data = (s_rtbuf_signal_delay_data*) rtb->data;
    while (i < RTBUF_SIGNAL_SAMPLES) {
      double s = in.sample_fun(in.signal, i);
      double d = min(max(0.0, delay.sample_fun(delay.signal, i)),
                     RTBUF_SIGNAL_DELAY_MAX);
      double fb = min(max(0.0, feedback.sample_fun(feedback.signal, i)), 1.0);
      unsigned int ds = d * RTBUF_SIGNAL_SAMPLERATE;
      unsigned int p = (data->pos + RTBUF_SIGNAL_DELAY_SAMPLES_MAX - ds) %
        RTBUF_SIGNAL_DELAY_SAMPLES_MAX;
      data->signal[i] = data->in[p];
      data->in[data->pos++] = (1.0 - fb) * s + fb * data->in[p];
      data->pos %= RTBUF_SIGNAL_DELAY_SAMPLES_MAX;
      i++;
    }
    return 0;
  }
  

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