git.gag.com Git - fw/altos/blob - ao-tools/lib/cc-period.c

   1 /*
   2  * Copyright © 2009 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 #include "cc.h"
  19 #include <stdlib.h>
  20
  21 struct cc_perioddata *
  22 cc_period_make(struct cc_timedata *td, double start_time, double stop_time)
  23 {
  24         int                     len = stop_time - start_time + 1;
  25         struct cc_perioddata    *pd;
  26         int                     i;
  27         double                  prev_time;
  28         double                  next_time;
  29         double                  interval;
  30
  31         pd = calloc(1, sizeof (struct cc_perioddata));
  32         pd->start = start_time;
  33         pd->step = 1;
  34         pd->num = len;
  35         pd->data = calloc(len, sizeof(double));
  36         prev_time = start_time;
  37         for (i = 0; i < td->num; i++) {
  38                 if (start_time <= td->data[i].time && td->data[i].time <= stop_time) {
  39                         int     pos = td->data[i].time - start_time;
  40
  41                         if (i < td->num - 1 && td->data[i+1].time < stop_time)
  42                                 next_time = (td->data[i].time + td->data[i+1].time) / 2.0;
  43                         else
  44                                 next_time = stop_time;
  45                         interval = next_time - prev_time;
  46                         pd->data[pos] = td->data[i].value * interval;
  47                         prev_time = next_time;
  48                 }
  49         }
  50         return pd;
  51 }
  52
  53 struct cc_perioddata *
  54 cc_period_low_pass(struct cc_perioddata *raw, double omega_pass, double omega_stop, double error)
  55 {
  56         struct cc_perioddata *filtered;
  57
  58         filtered = calloc (1, sizeof (struct cc_perioddata));
  59         filtered->start = raw->start;
  60         filtered->step = raw->step;
  61         filtered->num = raw->num;
  62         filtered->data = cc_low_pass(raw->data, raw->num, omega_pass, omega_stop, error);
  63         return filtered;
  64 }