LUMIERA.clone/src/lib/time/timequant.hpp

138 lines
3.9 KiB
C++

/*
TIMEQUANT.hpp - quantised (grid aligned) time values
Copyright (C) Lumiera.org
2010, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/** @file timequant.hpp
** Support library to represent grid-aligned time specifications
** This is part of Lumiera's time and time code handling framework.
** The QuTime entity represents the link between the internal precise
** time specifications and external representation formatted according
** to some well established time code format: QuTime both holds a precise
** internal time::TimeValue entry, plus a reference to the _time grid_ to
** be used, when it comes to _quantising_ (grid-aligning) those values.
** And it offers a dedicated API to "materialise" this (still complete and
** precise) time value into an external representation.
**
*/
#ifndef LIB_TIME_TIMEQUANT_H
#define LIB_TIME_TIMEQUANT_H
#include "lib/time/timevalue.hpp"
#include "lib/time/quantiser.hpp"
#include "lib/time/timecode.hpp"
#include "lib/symbol.hpp"
//#include <boost/operators.hpp>
#include <string>
namespace lib {
namespace time {
using lib::Symbol;
/**
* grid aligned time specification, referring to a specific scale.
* A quantised time value allows to access the time specification
* as numeric value in one of the supported timecode formats, and
* relative to the defined time scale. Usually this time scale
* exists already in the Lumiera session and is referred simply
* by symbolic ID, it will be fetched on demand through the
* \link advice.hpp advice system.\endlink
*
* By creating a QuTime value, the relation to such a predefined
* time scale is made explicit. This doesn't change the internal
* time value, but the actual creation of a timecode formatted
* value (#formatAs) usually implies to quantise or grid align
* the time to the frame grid specific to this time scale.
*/
class QuTime
: public Time
{
PQuant quantiser_;
public:
QuTime (TimeValue raw, Symbol gridID); ///< @note defined in common-services.cpp
QuTime (TimeValue raw, PQuant quantisation_to_use);
operator PQuant() const;
template<class FMT>
bool supports() const;
template<class FMT>
typename format::Traits<FMT>::TimeCode
formatAs() const;
template<class TC>
void
castInto (TC& timecode) const;
/** receive change message, which
might cause re-quantisation */
void accept (Mutation const&);
};
/* == implementation == */
inline
QuTime::operator PQuant() const
{
ASSERT (quantiser_);
return quantiser_;
}
template<class FMT>
inline bool
QuTime::supports() const
{
return quantiser_->supports<FMT>();
}
template<class FMT>
inline typename format::Traits<FMT>::TimeCode
QuTime::formatAs() const
{
typedef typename format::Traits<FMT>::TimeCode TC;
return TC(*this);
}
template<class TC>
inline void
QuTime::castInto (TC& timecode) const
{
typedef typename TC::Format Format;
REQUIRE (supports<Format>());
Format::rebuild (timecode, *quantiser_, TimeValue(*this));
}
}} // lib::time
#endif