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

648 lines
17 KiB
C++

/*
TIMEVALUE.hpp - basic definitions for time values and time intervals
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 timevalue.hpp
** a family of time value like entities and their relationships.
** This is the foundation for the Lumiera time handling framework. On the implementation
** level, time values are represented as 64bit integer values \c gavl_time_t. But for the
** actual use, we create several kinds of time "values", based on their logical properties.
** These time values are considered to be fixed (immutable) values, which may only be
** created through some well defined construction paths, and any time based calculation
** is forced to go through our time calculation library. This is prerequisite for
** the definition of <i>frame aligned</i> time values and time code representation
** implemented as display format based on these frame quantised time values.
**
** @see time.h basic time calculation library functions
** @see timequant.hpp
** @see TimeValue_test
**
*/
#ifndef LIB_TIME_TIMEVALUE_H
#define LIB_TIME_TIMEVALUE_H
#include "lib/error.hpp"
#include <boost/operators.hpp>
#include <boost/rational.hpp>
#include <cstdlib>
#include <string>
extern "C" {
#include <stdint.h>
#include <gavl/gavltime.h>
}
namespace lib {
namespace time {
namespace error = lumiera::error;
// forwards...
class FrameRate;
class TimeSpan;
class Mutation;
/**
* basic constant internal time value.
* These time values provide the implementation base
* for all further time types. They can be created by
* wrapping up a raw micro tick value (gavl_time_t),
* are totally ordered, but besides that,
* they are opaque and non-mutable.
* @note clients should prefer to use Time instances,
* which explicitly denote an Lumiera internal
* time value and are easier to use.
* @see TimeVar when full arithmetics are required
*/
class TimeValue
: boost::totally_ordered<TimeValue,
boost::totally_ordered<TimeValue, gavl_time_t>>
{
protected:
/** the raw (internal) time value
* used to implement the time types */
gavl_time_t t_;
/** Assigning of time values is not allowed,
* but derived classed might allow that */
TimeValue&
operator= (TimeValue const& o)
{
t_ = o.t_;
return *this;
}
/** some subclasses may receive modification messages */
friend class Mutation;
public:
/** explicit limit of allowed time range */
static gavl_time_t limited (gavl_time_t raw);
explicit
TimeValue (gavl_time_t val=0)
: t_(limited (val))
{ }
/** copy initialisation allowed */
TimeValue (TimeValue const& o)
: t_(o.t_)
{ }
/** @internal to pass Time values to C functions */
friend gavl_time_t _raw (TimeValue const& time) { return time.t_; }
static TimeValue buildRaw_(gavl_time_t);
/** @internal diagnostics */
operator std::string () const;
// Supporting totally_ordered
friend bool operator< (TimeValue const& t1, TimeValue const& t2) { return t1.t_ < t2.t_; }
friend bool operator< (TimeValue const& t1, gavl_time_t t2) { return t1.t_ < t2 ; }
friend bool operator> (TimeValue const& t1, gavl_time_t t2) { return t1.t_ > t2 ; }
friend bool operator== (TimeValue const& t1, TimeValue const& t2) { return t1.t_ == t2.t_; }
friend bool operator== (TimeValue const& t1, gavl_time_t t2) { return t1.t_ == t2 ; }
};
/** a mutable time value,
* behaving like a plain number,
* allowing copy and re-accessing
* @note supports scaling by a factor,
* which \em deliberately is chosen
* as int, not gavl_time_t, because the
* multiplying of times is meaningless.
*/
class TimeVar
: public TimeValue
, boost::additive<TimeVar,
boost::additive<TimeVar, TimeValue,
boost::multipliable<TimeVar, int>
> >
{
public:
TimeVar (TimeValue const& time = TimeValue())
: TimeValue(time)
{ }
// Allowing copy and assignment
TimeVar (TimeVar const& o)
: TimeValue(o)
{ }
TimeVar&
operator= (TimeValue const& o)
{
t_ = TimeVar(o);
return *this;
}
// Support mixing with plain long int arithmetics
operator gavl_time_t () const { return t_; }
// Supporting additive
TimeVar& operator+= (TimeVar const& tx) { t_ += tx.t_; return *this; }
TimeVar& operator-= (TimeVar const& tx) { t_ -= tx.t_; return *this; }
// Supporting multiplication with integral factor
TimeVar& operator*= (int64_t fact) { t_ *= fact; return *this; }
// Supporting sign flip
TimeVar operator- () const { return TimeVar(*this)*=-1; }
// baseclass TimeValue is already totally_ordered
};
/* ======= specific Time entities ==================== */
/** relative framecount or frame number.
* Used within the engine at places where the underlying
* grid and origin is obvious from the call context.
* @warning do not mix up gavl_time_t and FrameCnt.
* @warning use 64bit consistently.
* beware: \c long is 32bit on i386
* @note any conversion to frame numbers should go through
* time quantisation followed by conversion to FrameNr
*/
typedef int64_t FrameCnt;
/** rational representation of fractional seconds
* @warning do not mix up gavl_time_t and FSecs */
typedef boost::rational<long> FSecs;
/**
* Lumiera's internal time value datatype.
* This is a TimeValue, but now more specifically denoting
* a point in time, measured in reference to an internal
* (opaque) time scale.
*
* Lumiera Time provides some limited capabilities for
* direct manipulation; Time values can be created directly
* from \c (ms,sec,min,hour) specification and there is an
* string representation intended for internal use (reporting
* and debugging). Any real output, formatting and persistent
* storage should be based on the (quantised) timecode
* formats though, which can be generated from time values.
*
* Similar to TimeValue, also Time objects are considered
* immutable values. As convenience shortcut, some operators
* are provided, creating a TimVar for further calculations.
*/
class Time
: public TimeValue
{
/// direct assignment prohibited
Time& operator= (Time const);
/// suppress possible direct conversions
Time(int);
public:
static const Time MAX ;
static const Time MIN ;
static const Time ZERO;
static const Time ANYTIME; ///< border condition marker value. #ANYTIME <= any time value
static const Time NEVER; ///< border condition marker value. #NEVER >= any time value
explicit
Time (TimeValue const& val =TimeValue(0))
: TimeValue(val)
{ }
Time (TimeVar const& calcResult)
: TimeValue(calcResult)
{ }
explicit
Time (FSecs const& fractionalSeconds);
Time ( long millis
, uint secs
, uint mins =0
, uint hours=0
);
/** @internal diagnostics */
operator std::string () const;
/** convenience start for time calculations */
TimeVar operator+ (TimeValue const& tval) const { return TimeVar(*this) + tval; }
TimeVar operator- (TimeValue const& tval) const { return TimeVar(*this) - tval; }
TimeVar operator- () const { return -TimeVar(*this); }
};
/**
* Offset measures a distance in time.
* It may be used to relate two points in time,
* or to create a modification for time-like entities.
* Similar to (basic) time values, offsets can be compared,
* but are otherwise opaque and immutable. Yet they allow
* to build derived values, including
* - the \em absolute (positive) distance for this offset
* - a combined offset by chaining another offset
*/
class Offset
: public TimeValue
{
protected:
/** generally immutable,
* but derived classes allow some limited mutation
* through special API calls */
Offset&
operator= (Offset const& o)
{
TimeValue::operator= (o);
return *this;
}
public:
explicit
Offset (TimeValue const& distance =Time::ZERO)
: TimeValue(distance)
{ }
Offset (TimeValue const& origin, TimeValue const& target)
: TimeValue(TimeVar(target) -= origin)
{ }
Offset (FrameCnt count, FrameRate const& fps);
static const Offset ZERO;
TimeValue
abs() const
{
return TimeValue(std::llabs (t_));
}
/** @internal diagnostics, indicating ∆ */
operator std::string () const;
// Supporting sign flip
Offset operator- () const;
};
//-- support linear offset chaining ---------------
inline Offset
operator+ (Offset const& start, Offset const& toChain)
{
TimeVar distance(start);
distance += toChain;
return Offset(distance);
}
template<typename INT>
inline Offset
operator* (Offset const& distance, INT factor)
{
return factor*distance;
}
template<typename INT>
inline Offset
operator* (INT factor, Offset const& o)
{
TimeVar distance(o);
distance *= factor;
return Offset(distance);
}
template<typename INTX>
inline Offset
operator* (boost::rational<INTX> factor, Offset const& o)
{
return boost::rational<int64_t>(factor.numerator(), factor.denominator()) * o;
}
/** stretch offset by a possibly fractional factor */
Offset
operator* (boost::rational<int64_t> factor, Offset const& o);
/** flip offset direction */
inline Offset
Offset::operator- () const
{
return -1 * (*this);
}
/**
* Duration is the internal Lumiera time metric.
* It is an absolute (positive) value, but can be
* promoted from an offset. While Duration generally
* is treated as immutable value, there is the
* possibility to send a \em Mutation message.
*/
class Duration
: public TimeValue
{
/// direct assignment prohibited
Duration& operator= (Duration const&);
public:
Duration()
: Duration(Time::ZERO)
{ }
Duration (Offset const& distance)
: TimeValue(distance.abs())
{ }
explicit
Duration (TimeValue const& timeSpec)
: TimeValue(Offset(timeSpec).abs())
{ }
explicit
Duration (FSecs const& timeSpan_in_secs)
: TimeValue(Offset(Time(timeSpan_in_secs)).abs())
{ }
Duration (TimeSpan const& interval);
Duration (FrameCnt count, FrameRate const& fps);
static const Duration NIL;
void accept (Mutation const&);
/** @internal diagnostics */
operator std::string () const;
/// Supporting backwards use as offset
Offset operator- () const;
};
//-- support using a Duration to build offsets ---------------
inline Duration
operator+ (Duration const& base, Duration const& toAdd)
{
return Offset(base) + Offset(toAdd);
}
template<typename INT>
inline Offset
operator* (INT factor, Duration const& dur)
{
return factor * Offset(dur);
}
template<typename INT>
inline Offset
operator* (Duration const& dur, INT factor)
{
return factor*dur;
}
inline Offset
Duration::operator- () const
{
return -1 * (*this);
}
/**
* A time interval anchored at a specific point in time.
* The start point of this timespan is also its nominal
* position, and the end point is normalised to happen
* never before the start point. A TimeSpan is enough
* to fully specify the temporal properties of an
* object within the model.
*
* As an exception to the generally immutable Time
* entities, a non constant TimeSpan may receive
* \em mutation messages, both for the start point
* and the duration. This allows for changing
* position and length of objects in the timeline.
*
* @todo define these mutations
*/
class TimeSpan
: public Time
, boost::totally_ordered<TimeSpan>
{
Duration dur_;
public:
TimeSpan(TimeValue const& start, Duration const& length)
: Time(start)
, dur_(length)
{ }
TimeSpan(TimeValue const& start, Offset const& reference_distance)
: Time(start)
, dur_(reference_distance)
{ }
TimeSpan(TimeValue const& start, TimeValue const& end)
: Time(start)
, dur_(Offset(start,end))
{ }
TimeSpan(TimeValue const& start, FSecs(duration_in_secs))
: Time(start)
, dur_(duration_in_secs)
{ }
TimeSpan()
: TimeSpan(Time::ZERO, Time::ZERO)
{ }
Duration&
duration()
{
return dur_;
}
Duration
duration() const
{
return dur_;
}
Time
start() const
{
return *this;
}
Time
end() const
{
return TimeVar(*this) += dur_;
}
bool
contains (TimeValue const& tp) const
{
return *this <= tp
&& tp < end();
}
/** may change start / duration */
void accept (Mutation const&);
/** @internal diagnostics */
operator std::string () const;
/// Supporting extended total order, based on start and interval length
friend bool operator== (TimeSpan const& t1, TimeSpan const& t2) { return t1.t_==t2.t_ && t1.dur_==t2.dur_; }
friend bool operator< (TimeSpan const& t1, TimeSpan const& t2) { return t1.t_< t2.t_ ||
(t1.t_==t2.t_ && t1.dur_< t2.dur_);}
};
/**
* Framerate specified as frames per second.
* Implemented as rational number.
*/
class FrameRate
: public boost::rational<uint>
{
typedef boost::rational<uint> IFrac;
public:
FrameRate (uint fps) ;
FrameRate (uint num, uint denom);
FrameRate (IFrac const& fractionalRate);
// standard copy acceptable;
double asDouble() const;
static const FrameRate PAL;
static const FrameRate NTSC;
static const FrameRate HALTED;
/** duration of one frame */
Duration duration() const;
operator std::string() const;
};
/* == implementations == */
namespace { // implementation helpers...
template<typename NUM>
inline NUM
__ensure_nonzero (NUM n)
{
if (n == 0)
throw error::Logic ("Degenerated frame grid not allowed"
, error::LERR_(BOTTOM_VALUE));
return n;
}
}//(End) implementation helpers
/** @internal applies a limiter on the provided
* raw time value to keep it within the arbitrary
* boundaries defined by (Time::MAX, Time::MIN).
* While Time entities are \c not a "safeInt"
* implementation, we limit new values and
* establish this safety margin to prevent
* wrap-around during time quantisation */
inline gavl_time_t
TimeValue::limited (gavl_time_t raw)
{
return raw > Time::MAX? Time::MAX.t_
: raw < Time::MIN? Time::MIN.t_
: raw;
}
inline
Duration::Duration (TimeSpan const& interval)
: TimeValue(interval.duration())
{ }
inline
FrameRate::FrameRate (uint fps)
: IFrac (__ensure_nonzero(fps))
{ }
inline
FrameRate::FrameRate (uint num, uint denom)
: IFrac (__ensure_nonzero(num), denom)
{ }
inline
FrameRate::FrameRate (IFrac const& fractionalRate)
: IFrac (__ensure_nonzero(fractionalRate))
{ }
inline double
FrameRate::asDouble() const
{
return boost::rational_cast<double> (*this);
}
}} // lib::time
namespace util {
inline bool
isnil (lib::time::Duration const& dur)
{
return 0 == dur;
}
}
#endif