From e63b2f75607905fedf00cfd9fe644b26af715ffd Mon Sep 17 00:00:00 2001 From: Leo C Date: Mon, 1 Dec 2014 23:25:55 +0100 Subject: switch to avr-libc 1.8.1 time library --- time/solar_noon.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 time/solar_noon.c (limited to 'time/solar_noon.c') diff --git a/time/solar_noon.c b/time/solar_noon.c new file mode 100644 index 0000000..65bafcc --- /dev/null +++ b/time/solar_noon.c @@ -0,0 +1,57 @@ +/* + * (c)2012 Michael Duane Rice All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: + * + * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. Redistributions in binary + * form must reproduce the above copyright notice, this list of conditions + * and the following disclaimer in the documentation and/or other materials + * provided with the distribution. Neither the name of the copyright holders + * nor the names of contributors may be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +/* $Id: solar_noon.c 2365 2013-04-27 15:32:59Z swfltek $ */ + +/* + Return the time of solar noon at the observers position +*/ + +#include + +extern long __longitude; + +time_t +solar_noon(const time_t * timer) +{ + time_t t; + long n; + + /* determine time of solar noon at the prime meridian */ + t = *timer % ONE_DAY; + t = *timer - t; + t += 43200L; + t -= equation_of_time(timer); + + /* rotate to observers longitude */ + n = __longitude / 15L; + t -= n; + + return t; + +} -- cgit v1.2.3