This is mostly a simple lexical search+replace but the absence of operator< for
std::weak_ptr<T> leads to some complications, particularly with Evoral::Sequence
and ExportPortChannel.
This resolves an ambiguity between abs(int) and std::abs(T) which
depends on context and compiler version and optimization.
In context of #9057, (gcc-6.3 -O3) math.h `abs(int)` was used. This
truncated the superclock value to 31 bit in ControlList::extend_to.
There were many logical errors in the previous implementation. This one is
simpler to read, and appears to work much better.
It also allows the caller to specify the quarter-note subdivision to use when
generating the grid, rather than choosing only between some bar modulo or
quarter notes.
This is never for inline references to parameters, only for starting parameter
documentation blocks. The "@p" command is for this, although unfortunately
Doxygen doesn't actually do anything with it and it's just an alias for code
text.
This fixes various rounding issues. Notably superclock to sample
conversion must always round down when playing forward.
`::process (start, end, speed = 1)` uses exclusive end.
Processing begins at `start` and end ends just before `end`.
Next cycle will begin with the current end.
One example where this failed:
- New session at 48kHz
- Change tempo to 130 BPM
- Enable snap to 1/8 note
- Snap playhead to 1|3|0
- Enable Metronome
- Play
`assert (superclock_to_samples ((*i).sclock(), sample_rate()) < end);`
end = 177231 samples == superclock 1042118280
A grid point is found at superclock 1042116920 (that is < 1042118280).
However converting it back to samples rounded it to sample 177231 == end,
while actual location is 1360 super-clock ticks before end.
The metronome click has to be started this cycle, since the same
position will not be found at the beginning of the next cycle, with
start = 177232.
Similarly a samplecnt_t t, converted to music-time and back must not be
later than the given sample.
```
timepos_t tsc (t);
assert (timepos_t::from_ticks (tsc.ticks ()).samples () <= t);
```
IOW. When playing forward, all super-clock time between 1|1|0 and 1|1|1
should round down to 1|1|0. "We have not yet reached the first tick".
The default clock-limit is 99:59:59:00, just under 360000 seconds
(see ARDOUR_UI::parameter_changed, clock-display-limit).
AudioClock calculates this limit pos as
`timepos_t (limit_sec * _session->sample_rate())`
This caused an overflow leading to a negative value:
```
timepos_t (359999 * 96000)
samples_to_superclock (359999 * 96000, 96000)
int_div_round (359999 * 96000 * 282240000, 96000)
```
Ideally this will be optimized, here the sample-rate cancels out,
so we could use a c'tor usin seconds.
In other cases we could cache the pre-calculated sc_per_sample:
`superclock_ticks_per_second() / superclock_t (sr)` which is an
integer for all commonly used sample-rates.
audio time nominally uses superclocks as its canonical unit. However
many things at a higher level only understand samples. If we
increment or decrement a superclock value by 1, the vast majority of
the time we will still get the same sample value after
conversion. Thus to correctly alter an audio time by an amount
that will manifest as 1 sample's difference, we have to use
samples_to_superclock(1)
Usually C++ class instance has the same mem address as its first parent.
LuaBridge uses this to for derived classes. A TemopPoint instance has
the same address as its parent Tempo. However due to virtual inheritance
this was not the case due to a lack of virtual d'tor.
Now the following Lua code works correctly
```
tm = Temporal.TempoMap.read()
tp = Temporal.timepos_t (0)
print (tm:tempo_at(tp):note_type())
```
Previously the last line failed calling Tempo::note_type()
on a TempoPoint instance, due to memory offset e.g.
TempoPoint: 0x600000ff90e0 Tempo: 0x600000ff90e8
