LUMIERA.clone/src/lib/time/mutation.cpp
Ichthyostega 22322dfec4 refactor the division/quantisation helpers
...no need to keep them in util.hpp, as they
are used rather occasionally, while util.hpp
is used pervasively.
2012-10-10 05:20:12 +02:00

360 lines
10 KiB
C++

/*
Mutation - changing and adjusting time values
Copyright (C) Lumiera.org
2011, 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.
* *****************************************************/
#include "lib/error.hpp"
#include "lib/time/timevalue.hpp"
#include "lib/time/timequant.hpp"
#include "lib/time/timecode.hpp"
#include "lib/time/mutation.hpp"
//#include "lib/time.h"
#include "lib/util-quant.hpp"
#include "lib/util.hpp"
//#include <tr1/functional>
//using std::string;
//using util::unConst;
//using util::floorwrap;
using util::isnil;
namespace error = lumiera::error;
namespace lib {
namespace time {
LUMIERA_ERROR_DEFINE (INVALID_MUTATION, "Changing a time value in this way was not designated");
Mutation::~Mutation() { } // emit VTable here....
/**
* concrete time value mutation:
* impose fixed new start time.
*/
class SetNewStartTimeMutation
: public ClonableMutation
{
TimeValue newTime_;
virtual void
change (Duration&) const
{
throw error::Logic ("mutating the start point of a pure Duration doesn't make sense"
, LUMIERA_ERROR_INVALID_MUTATION);
}
virtual void
change (TimeSpan& target) const
{
imposeChange (target, newTime_);
}
/** @note the re-quantisation happens automatically
* when the (changed) QuTime is materialised */
virtual void
change (QuTime& target) const
{
imposeChange (target, newTime_);
}
public:
explicit
SetNewStartTimeMutation (TimeValue t)
: newTime_(t)
{ }
};
/**
* concrete time value mutation:
* set a new overall duration for an extended timespan.
*/
class SetNewDuration
: public ClonableMutation
{
Duration changedDuration_;
virtual void
change (Duration& target) const
{
imposeChange (target, changedDuration_);
}
virtual void
change (TimeSpan& target) const
{
imposeChange (target.duration(), changedDuration_);
}
/** @note the re-quantisation happens automatically
* when the (changed) QuTime is materialised */
virtual void
change (QuTime&) const
{
throw error::Logic ("mutating the duration of a (quantised) time point doesn't make sense"
, LUMIERA_ERROR_INVALID_MUTATION);
}
public:
explicit
SetNewDuration (Duration dur)
: changedDuration_(dur)
{ }
};
/**
* concrete time value mutation:
* adjust the given time entity by an offset amount.
*/
class ImposeOffsetMutation
: public ClonableMutation
{
Offset adjustment_;
virtual void
change (Duration& target) const
{
imposeChange (target, adjustment_);
}
virtual void
change (TimeSpan& target) const
{
imposeChange (target, adjustment_);
}
/** @note the re-quantisation happens automatically
* when the (changed) QuTime is materialised */
virtual void
change (QuTime& target) const
{
imposeChange (target, adjustment_);
}
public:
explicit
ImposeOffsetMutation (Offset adj)
: adjustment_(adj)
{ }
};
/**
* concrete time value mutation:
* make the grid aligned time value explicit,
* and impose the resulting value to the given
* time points (or start points).
*/
class MaterialiseIntoTarget
: public SetNewStartTimeMutation
{
public:
explicit
MaterialiseIntoTarget (QuTime const& quant)
: SetNewStartTimeMutation (PQuant(quant)->materialise(quant))
{ }
};
/**
* concrete time value mutation:
* nudge target value by the given number of 'steps',
* relative to the given grid.
*/
class NudgeMutation
: public ImposeOffsetMutation
{
static Offset
materialiseGridPoint (Symbol gridID, int steps)
{
REQUIRE (!isnil (gridID));
PQuant grid = Quantiser::retrieve(gridID);
return Offset(grid->timeOf(0), grid->timeOf(steps));
}
public:
NudgeMutation (int relativeSteps, Symbol gridID)
: ImposeOffsetMutation(materialiseGridPoint (gridID,relativeSteps))
{ }
};
/**
* concrete time value mutation:
* nudge based on a implicit grid, which is
* either a quantised target value's own grid,
* or a \em natural grid.
* @note currently the natural grid is hard wired,
* just interpreting the step parameter as
* offset in seconds.
* @see mutation#imposeChange (TimeValue, int)
* @see mutation#imposeChange (QuTime, int)
*/
class NaturalNudgeMutation
: public ClonableMutation
{
int steps_;
virtual void
change (Duration& target) const
{
imposeChange (target, steps_);
}
virtual void
change (TimeSpan& target) const
{
imposeChange (target, steps_);
}
/** @note special treatment: use the quantised time's own grid */
virtual void
change (QuTime& target) const
{
imposeChange (target, steps_);
}
public:
explicit
NaturalNudgeMutation (int relativeSteps)
: steps_(relativeSteps)
{ }
};
/** Convenience factory to yield a simple Mutation changing the absolute start time.
* This whole procedure might look quite inefficient, but actually most of the
* abstractions are removed at runtime, leaving only a single indirection
* through the VTable of the Mutation Interface.
* @throw error::Logic when attempting to change the (non existent) start time of a Duration
* @return EncapsulatedMutation, which is an "polymorphic value object",
* actually carrying an embedded Mutation subclass with the new start time
*/
EncapsulatedMutation
Mutation::changeTime (Time newStartTime)
{
return EncapsulatedMutation::build<SetNewStartTimeMutation> (newStartTime);
}
/** Convenience factory: simple Mutation to adjust the duration or length of a timespan
* @throw error::Logic when attempting to change the "duration" of a quantised time point
* @return EncapsulatedMutation, carrying the new duration value to impose
*/
EncapsulatedMutation
Mutation::changeDuration (Duration changedDur)
{
return EncapsulatedMutation::build<SetNewDuration> (changedDur);
}
/** Convenience factory: simple Mutation to adjust the duration or length of a timespan
* @throw error::Logic when attempting to change the "duration" of a quantised time point
* @return EncapsulatedMutation, carrying the new duration value to impose
*/
EncapsulatedMutation
Mutation::adjust (Offset change)
{
return EncapsulatedMutation::build<ImposeOffsetMutation> (change);
}
/** Convenience factory: materialise the given quantised time into an explicit fixed
* internal time value, according to the underlying time grid; impose the resulting
* value then as new time point or start point to the target
* @note same as materialising and then invoking #changeTime
*/
EncapsulatedMutation
Mutation::materialise (QuTime const& gridAlignedTime)
{
return EncapsulatedMutation::build<MaterialiseIntoTarget> (gridAlignedTime);
}
/** build a time mutation to \em nudge the target time value by an offset,
* defined as number of steps on an implicit nudge grid. If the target is an
* continuous (not quantised) time value or duration, an internal 'default nudge grid'
* will be used to calculate the offset value. Typically, this grid counts in seconds.
* To the contrary, when the target is a quantised value, it will be aligned to the
* grid point relative to the current value's next grid point, measured in number
* of steps. This includes \em materialising the internal time to the exact grid
* position. If especially the adjustment is zero, the internal value will
* be changed to literally equal the current value's next grid point.
*/
EncapsulatedMutation
Mutation::nudge (int adjustment)
{
return EncapsulatedMutation::build<NaturalNudgeMutation> (adjustment);
}
/** build a time mutation to \em nudge the target time value; the nudge time grid
* is specified explicitly here, instead of using a global or 'natural' nudge grid.
* In case the target itself is a quantised time value, a chaining of the two
* grids will happen: first, the nudge grid is used to get an offset value,
* according to the number of steps, then this offset is applied to the
* raw value underlying the quantised target. If this resulting target
* value later will be cast into any kind of time code or materialised
* otherwise, the quantised value's own grid will apply as well,
* resulting in the net result of two quantisation operations
* being applied in sequence.
* @param adjustment number of grid steps to apply as offset
* @param gridID symbolic name used to register or define a
* suitable nudge grid, typically somewhere globally
* in the session (as meta asset)
*/
EncapsulatedMutation
Mutation::nudge (int adjustment, Symbol gridID)
{
return EncapsulatedMutation::build<NudgeMutation> (adjustment, gridID);
}
}} // lib::time