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Temporal: remove constructors accepting scalar values from timepos_t/timecnt_t and force use of factory methods

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This allows us to differentiate between superclock_t and samplepos_t (and related types) which are all typedef'ed to the
same underlying primitive C++ type. Without this, it would be impossible for the compiler or someone reading the code
to know whether a scalar passed to a constructor for a timeline type is in units of samples or superclocks
This commit is contained in:
Paul Davis 2020-08-11 18:26:25 -06:00
parent c75fc64306
commit f06e2dd6d1
3 changed files with 111 additions and 138 deletions
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6
libs/temporal/tempo.cc
View File

@ -77,7 +77,7 @@ Point::time() const
{
switch (_map->time_domain()) {
case AudioTime:
return timepos_t (sclock());
return timepos_t::from_superclock (sclock());
case BeatTime:
return timepos_t (beats());
case BarTime:
@ -2508,7 +2508,7 @@ TempoMap::full_duration_at (timepos_t const & pos, timecnt_t const & duration, T
/* determine superclocks */
s = metric_at (p).superclock_at (p.beats());
/* return duration in sc */
return timecnt_t (s - pos.superclocks(), pos);
return timecnt_t::from_superclock (s - pos.superclocks(), pos);
break;
}
break;
@ -2545,7 +2545,7 @@ TempoMap::full_duration_at (timepos_t const & pos, timecnt_t const & duration, T
abort ();
/*NOTREACHED*/
return timecnt_t (0, timepos_t());
return timecnt_t::from_superclock (0);
}

120
libs/temporal/temporal/timeline.h
View File

@ -38,18 +38,23 @@ namespace Temporal {
class timecnt_t;
/* 62 bit time value.
* 63rd bit: indicates music or audio time value
* 64th bit: sign bit
/* 62 bit positional time value. Theoretically signed, but the intent is for to
* always be positive. If the flag bit is set (i.e. ::flagged() is true), the
* numerical value counts musical ticks; otherwise it counts superclocks.
*/
class timepos_t : public int62_t {
class LIBTEMPORAL_API timepos_t : public int62_t {
public:
timepos_t () : int62_t (false, 0) {}
timepos_t (superclock_t s) : int62_t (false, s) {}
explicit timepos_t (timecnt_t const &); /* will throw() if val is negative */
explicit timepos_t (Temporal::Beats const & b) : int62_t (false, b.to_ticks()) {}
/* superclock_t and samplepos_t are the same underlying primitive type,
* which means we cannot use polymorphism to differentiate them.
*/
static timepos_t from_superclock (superclock_t s) { return timepos_t (false, s); }
static timepos_t from_samples (superclock_t s) { return timepos_t (false, samples_to_superclock (s, _thread_sample_rate)); }
bool is_beats() const { return flagged(); }
bool is_superclock() const { return !flagged(); }
@ -60,24 +65,6 @@ class timepos_t : public int62_t {
int64_t ticks() const { if (is_beats()) return val(); return _ticks (); }
Beats beats() const { if (is_beats()) return Beats::ticks (val()); return _beats (); }
/* return a timepos_t that is the next (later) possible position given
* this one
*/
timepos_t increment () const {
return timepos_t (val() + 1);
}
/* return a timepos_t that is the previous (earlier) possible position given
* this one
*/
timepos_t decrement () const {
if (is_beats()) {
return timepos_t (val() - 1); /* beats can go negative */
}
return timepos_t (val() > 0 ? val() - 1 : val()); /* samples cannot go negative */
}
timepos_t & operator= (timecnt_t const & t); /* will throw() if val is negative */
timepos_t & operator= (superclock_t s) { v = s; return *this; }
timepos_t & operator= (Temporal::Beats const & b) { operator= (build (true, b.to_ticks())); return *this; }
@ -96,9 +83,15 @@ class timepos_t : public int62_t {
bool operator>= (timepos_t const & other) const { if (is_beats() == other.is_beats()) return val() >= other.val(); return expensive_gte (other); }
timepos_t operator+(timecnt_t const & d) const;
timepos_t operator+(timepos_t const & d) const { if (is_beats() == d.is_beats()) return timepos_t (v + d.ticks()); return expensive_add (d.superclocks()); }
timepos_t operator+(superclock_t s) const { if (is_superclock()) return timepos_t (v + s); return expensive_add (s); }
timepos_t operator+(Temporal::Beats const &b ) const { if (is_beats()) return timepos_t (ticks() + b.to_ticks()); return expensive_add (b); }
timepos_t operator+(timepos_t const & d) const { if (is_beats() == d.is_beats()) return timepos_t (is_beats(), val() + d.val()); return expensive_add (d); }
timepos_t operator+(Temporal::Beats const &b ) const { if (is_beats()) return timepos_t (true, ticks() + b.to_ticks()); return expensive_add (b); }
/* donn't provide operator+(samplepos_t) or operator+(superclock_t)
* because the compiler can't disambiguate them and neither can we.
* to add such types, use ::from_samples() or ::from_superclock() to
* create a timepo_t and then add that.
*/
/* operator-() poses severe and thorny problems for a class that represents position on a timeline.
*
@ -130,39 +123,45 @@ class timepos_t : public int62_t {
*/
/* computes the distance between this timepos_t and @param p
such that: this + distance = p
* such that: this + distance = p
*
* This means that if @param p is later than this, distance is positive;
* if @param p is earlier than this, distance is negative.
This means that if @param p is later than this, distance is positive;
if @param p is earlier than this, distance is negative.
Note that the return value is a timecnt_t whose position member
is equal to the value of this. That means if the distance uses
musical time value, the distance may not have constant value
at other positions on the timeline.
* Note that the return value is a timecnt_t whose position member
* is equal to the value of this. That means if the distance uses
* musical time value, the distance may not have constant value
* at other positions on the timeline.
*/
timecnt_t distance (timecnt_t const & p) const;
timecnt_t distance (superclock_t s) const;
timecnt_t distance (Temporal::Beats const & b) const;
timecnt_t distance (timepos_t const & p) const;
/* computes a new position value that is @param d earlier than this */
timepos_t earlier (timepos_t const & d) const; /* treat d as distance measured from timeline origin */
timepos_t earlier (timecnt_t const & d) const;
timepos_t earlier (samplepos_t d) const;
timepos_t earlier (Beats const & d) const;
timepos_t earlier (BBT_Offset const & d) const;
/* like ::earlier() but changes this. loosely equivalent to operator-= */
timepos_t & shift_earlier (timecnt_t const & d);
timepos_t & shift_earlier (samplepos_t);
timepos_t & shift_earlier (Temporal::Beats const &);
timepos_t & shift_earlier (Temporal::BBT_Offset const &);
/* given the absence of operator- and thus also operator--, return a
* timepos_t that is the previous (earlier) possible position given
* this one
*/
timepos_t decrement () const { return timepos_t (false, val() > 0 ? val() - 1 : val()); /* cannot go negative */ }
/* purely for reasons of symmetry with ::decrement(), return a
* timepos_t that is the next (later) possible position given this one
*/
timepos_t increment () const { return timepos_t (flagged(), val() + 1); }
timepos_t & operator+=(timecnt_t const & d);
timepos_t & operator+=(samplepos_t);
timepos_t & operator+=(timepos_t const & d);
timepos_t & operator+=(Temporal::Beats const &);
timepos_t & operator+=(Temporal::BBT_Offset const &);
@ -222,11 +221,10 @@ class timepos_t : public int62_t {
/* used to compute distance when time domains do not match */
timecnt_t expensive_distance (timepos_t const & p) const;
timecnt_t expensive_distance (superclock_t s) const;
timecnt_t expensive_distance (Temporal::Beats const & b) const;
timecnt_t expensive_distance (Beats const &) const;
timepos_t expensive_add (Temporal::Beats const &) const;
timepos_t expensive_add (superclock_t s) const;
timepos_t expensive_add (timepos_t const & s) const;
using int62_t::operator int64_t;
using int62_t::operator-;
@ -259,22 +257,29 @@ class timepos_t : public int62_t {
class LIBTEMPORAL_API timecnt_t {
public:
/* default to zero superclocks @ zero */
timecnt_t () : _distance (int62_t (false, 0)), _position (superclock_t(0)) {}
timecnt_t () : _distance (int62_t (false, 0)), _position (timepos_t::from_superclock (0)) {}
timecnt_t (timecnt_t const &other) : _distance (other.distance()), _position (other.position()) {}
/* construct from timeline types */
timecnt_t (timepos_t const & d, timepos_t const & p) : _distance (d), _position (p) { assert (p.is_beats() == d.is_beats()); }
timecnt_t (timecnt_t const &, timepos_t const & pos);
explicit timecnt_t (timepos_t const & d, timepos_t const & p) : _distance (d), _position (p) { assert (p.is_beats() == d.is_beats()); }
explicit timecnt_t (timecnt_t const &, timepos_t const & pos);
/* construct from int62_t (which will be flagged or not) and timepos_t */
timecnt_t (int62_t d, timepos_t p) : _distance (d), _position (p) { assert (p.is_beats() == d.flagged()); }
explicit timecnt_t (int62_t d, timepos_t p) : _distance (d), _position (p) { assert (p.is_beats() == d.flagged()); }
/* construct from position/distance primitives */
explicit timecnt_t (superclock_t s, timepos_t const & pos) : _distance (false, s), _position (pos) { assert (_distance.flagged() == _position.is_beats()); }
/* construct from beats */
explicit timecnt_t (Temporal::Beats const & b, timepos_t const & pos) : _distance (true, b.to_ticks()), _position (pos) { assert ( _distance.flagged() == _position.is_beats()); }
/* superclock_t and samplepos_t are the same underlying primitive type,
* which means we cannot use polymorphism to differentiate them.
*/
static timecnt_t from_superclock (superclock_t s, timepos_t const & pos) { return timecnt_t (int62_t (false, s), pos); }
static timecnt_t from_samples (samplepos_t s, timepos_t const & pos) { return timecnt_t (int62_t (false, samples_to_superclock (s, _thread_sample_rate)), pos); }
/* Construct from just a distance value - position is assumed to be zero */
explicit timecnt_t (superclock_t s) : _distance (false, s), _position (superclock_t (0)) {}
explicit timecnt_t (Temporal::Beats const & b) : _distance (true, b.to_ticks()), _position (Beats()) {}
static timecnt_t from_superclock (superclock_t s) { return timecnt_t (int62_t (false, s), timepos_t::from_superclock (0)); }
static timecnt_t from_samples (samplepos_t s) { return timecnt_t (int62_t (false, samples_to_superclock (s, _thread_sample_rate)), timepos_t::from_superclock (0)); }
int62_t const & distance() const { return _distance; }
timepos_t const & position() const { return _position; }
@ -385,7 +390,7 @@ namespace std {
/* The utility of these two specializations of std::numeric_limits<> is not
* clear, since both timepos_t and timecnt_t have a time domain, and comparing
* across time domains, while possible, is expensive.
* across time domains, while possible, is expensive.
*
* To avoid hidden costs, it seems easier to use timepos_t::max and
* timecnt_t::max although these have a similar fundamental problem.
@ -394,21 +399,17 @@ namespace std {
template<>
struct numeric_limits<Temporal::timepos_t> {
static Temporal::timepos_t min() {
return Temporal::timepos_t (0);
return Temporal::timepos_t::from_superclock (0);
}
static Temporal::timepos_t max() {
return Temporal::timepos_t (4611686018427387904); /* pow (2,62) */
return Temporal::timepos_t::from_superclock (4611686018427387904); /* pow (2,62) */
}
};
template<>
struct numeric_limits<Temporal::timecnt_t> {
static Temporal::timecnt_t min() {
return Temporal::timecnt_t (Temporal::superclock_t (0), Temporal::timepos_t (Temporal::superclock_t (0)));
}
static Temporal::timecnt_t max() {
return Temporal::timecnt_t (Temporal::superclock_t (4611686018427387904), Temporal::timepos_t (Temporal::superclock_t (0))); /* pow (2,62) */
}
static Temporal::timecnt_t min() { return Temporal::timecnt_t::from_superclock (0); }
static Temporal::timecnt_t max() { return Temporal::timecnt_t::from_superclock (4611686018427387904); /* pow (2,62) */ }
};
}
@ -454,4 +455,3 @@ inline static bool operator>= (Temporal::Beats const & b, Temporal::timecnt_t co
#undef TEMPORAL_DOMAIN_WARNING
#endif /* __libtemporal_timeline_h__ */

123
libs/temporal/timeline.cc
View File

@ -67,7 +67,7 @@ static TemporalStatistics stats;
/* timecnt */
timecnt_t timecnt_t::_max_timecnt (int62_t::max - 1, timepos_t());
timecnt_t timecnt_t::_max_timecnt (timecnt_t::from_superclock (int62_t::max - 1));
timecnt_t::timecnt_t (timecnt_t const & tc, timepos_t const & pos)
: _position (pos)
@ -112,13 +112,17 @@ timecnt_t::compute_beats() const
timecnt_t
timecnt_t::operator*(ratio_t const & r) const
{
return timecnt_t (int_div_round (_distance.val() * r.numerator(), r.denominator()), _position);
const int62_t v (_distance.flagged(), int_div_round (_distance.val() * r.numerator(), r.denominator()));
return timecnt_t (v, _position);
}
timecnt_t
timecnt_t::operator/(ratio_t const & r) const
{
return timecnt_t (int_div_round (_distance.val() * r.denominator(), r.numerator()), _position);
/* note: x / (N/D) => x * (D/N) => (x * D) / N */
const int62_t v (_distance.flagged(), int_div_round (_distance.val() * r.denominator(), r.numerator()));
return timecnt_t (v, _position);
}
timecnt_t
@ -260,14 +264,21 @@ timepos_t::_ticks () const
timepos_t
timepos_t::expensive_add (Beats const & b) const
{
assert (is_beats());
assert (!is_beats());
return timepos_t (beats() + b);
}
timepos_t
timepos_t::expensive_add (superclock_t sc) const
timepos_t::expensive_add (timepos_t const & t) const
{
return timepos_t (val() + sc);
assert (is_beats() != t.is_beats ());
if (is_beats()) {
return timepos_t (beats() + t.beats());
}
return timepos_t::from_superclock (superclocks() + t.superclocks());
}
/* */
@ -276,21 +287,11 @@ timepos_t::expensive_add (superclock_t sc) const
* thus returns a positive value if this condition is satisfied.
*/
timecnt_t
timepos_t::distance (superclock_t s) const
{
if (is_superclock()) {
return timecnt_t (s - val(), *this);
}
return expensive_distance (s);
}
timecnt_t
timepos_t::distance (Beats const & b) const
{
if (is_beats()) {
return timecnt_t ((b - _beats()).to_ticks(), *this);
return timecnt_t (b - _beats(), *this);
}
return expensive_distance (b);
@ -303,17 +304,7 @@ timepos_t::distance (timepos_t const & d) const
return distance (d._beats());
}
return distance (d._superclocks());
}
timecnt_t
timepos_t::expensive_distance (superclock_t s) const
{
if (is_superclock() && (val() < s)) {
PBD::warning << string_compose (_("programming warning: sample arithmetic will generate negative sample time (%1 - %2)"), superclocks(), s) << endmsg;
}
return timecnt_t (s - superclocks(), *this);
return expensive_distance (d);
}
timecnt_t
@ -322,27 +313,18 @@ timepos_t::expensive_distance (Temporal::Beats const & b) const
return timecnt_t (b - beats(), *this);
}
/* */
timepos_t
timepos_t:: earlier (superclock_t s) const
timecnt_t
timepos_t::expensive_distance (timepos_t const & p) const
{
superclock_t sc;
if (is_beats()) {
TempoMap::SharedPtr tm (TempoMap::use());
sc = tm->superclock_at (beats());
} else {
sc = val();
return timecnt_t (beats() + p.beats(), *this);
}
if (sc < s) {
PBD::warning << string_compose (_("programming warning: sample arithmetic will generate negative sample time (%1 - %2)"), superclocks(), s) << endmsg;
}
return timepos_t (sc - s);
return timecnt_t::from_superclock (superclocks() + p.superclocks(), *this);
}
/* */
timepos_t
timepos_t::earlier (Temporal::Beats const & b) const
{
@ -389,23 +371,6 @@ timepos_t::shift_earlier (timecnt_t const & d)
return shift_earlier (d.beats());
}
timepos_t &
timepos_t:: shift_earlier (superclock_t s)
{
superclock_t sc;
if (is_beats ()) {
TempoMap::SharedPtr tm (TempoMap::use());
sc = tm->superclock_at (beats());
} else {
sc = val();
}
v = sc - s;
return *this;
}
timepos_t &
timepos_t::shift_earlier (Temporal::Beats const & b)
{
@ -425,19 +390,6 @@ timepos_t::shift_earlier (Temporal::Beats const & b)
/* */
timepos_t &
timepos_t:: operator+= (superclock_t s)
{
if (is_superclock()) {
v += s;
} else {
TempoMap::SharedPtr tm (TempoMap::use());
v = build (true, tm->scwalk_to_quarters (beats(), s).to_ticks());
}
return *this;
}
timepos_t &
timepos_t::operator+=(Temporal::Beats const & b)
{
@ -457,7 +409,7 @@ timepos_t
timepos_t::operator+(timecnt_t const & d) const
{
if (d.time_domain() == AudioTime) {
return operator+ (d.superclocks());
return operator+ (timepos_t::from_superclock (d.superclocks()));
}
return operator+ (d.beats());
@ -467,11 +419,32 @@ timepos_t &
timepos_t::operator+=(timecnt_t const & d)
{
if (d.time_domain() == AudioTime) {
return operator+= (d.superclocks());
return operator+= (timepos_t::from_superclock (d.superclocks()));
}
return operator+= (d.beats());
}
/* */
timepos_t &
timepos_t::operator+=(timepos_t const & d)
{
if (d.is_beats() == is_beats()) {
v = build (flagged(), val() + d.val());
} else {
if (is_beats()) {
v = build (false, val() + d.ticks());
} else {
v = build (true, val() + d.superclocks());
}
}
return *this;
}
std::ostream&
std::operator<< (std::ostream & o, timepos_t const & tp)