livetrax/libs/temporal/bbt_time.cc

/*
  Copyright (C) 2002-2010 Paul Davis

  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser 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 Lesser General Public
  License for more details.

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

#include <cmath>
#include <cassert>

#include "temporal/bbt_time.h"

using namespace Timecode;

/* This defines the smallest division of a "beat".

   The number is intended to have as many integer factors as possible so that
   1/Nth divisions are integer numbers of ticks.

   1920 has many factors, though going up to 3840 gets a couple more.

   This needs to match Temporal::Beats::PPQN
*/

const double BBT_Time::ticks_per_beat = 1920.0;

BBT_Offset::BBT_Offset (double dbeats)
{
	/* NOTE: this does not construct a BBT time in a canonical form,
	   in that beats may be a very large number, and bars will
	   always be zero. Hence ... it's a BBT_Offset
	*/

	assert (dbeats >= 0);

	bars = 0;
	beats = lrint (floor (dbeats));
	ticks = lrint (floor (BBT_Time::ticks_per_beat * fmod (dbeats, 1.0)));
}