gpstime.c

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/*
 * Copyright (C) 2013 Swift Navigation Inc.
 * Contact: Fergus Noble <fergus@swift-nav.com>
 *
 * This source is subject to the license found in the file 'LICENSE' which must
 * be be distributed together with this source. All other rights reserved.
 *
 * THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
 * EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <math.h>

#include "gpstime.h"

/* TODO: Either normalise in place or rename to normalised. */
gps_time_t normalize_gps_time(gps_time_t t)
{
  while(t.tow < 0) {
    t.tow += 3600*24*7;
    t.wn += 1;
  }

  while(t.tow > 3600*24*7) {
    t.tow -= 3600*24*7;
    t.wn -= 1;
  }

  return t;
}

time_t gps2time(gps_time_t gps_t)
{
  time_t t = GPS_EPOCH - GPS_MINUS_UTC_SECS;

  t += 7*24*3600*gps_t.wn;
  t += (s32)gps_t.tow;

  return t;
}

double gpsdifftime(gps_time_t end, gps_time_t beginning)
{
  return (end.wn - beginning.wn)*7*24*3600 + \
         end.tow - beginning.tow;
}