class EventSequence(object):
"""
A class to collect a sequence of Event's ordered (increasing) by the Event's time value.
The class contains the following event accounting structures:
1) OrderedMap: ordering the events by time in a map that provides a floor() function.
2) successor: a dict that maps events to successors.
3) predecessor: a dict that maps events to predecessors.
4) first: first event in the event sequence.
5) last: last event in the event sequence.
"""
def __init__(self, event_list=None):
"""
Constructor.
Args:
event_list: Any of None, a single Event, or a list of Events.
"""
self.ordered_map = OrderedMap()
self._successor = {}
self._predecessor = {}
self.__first = None
self.__last = None
if event_list:
self.add(event_list)
@property
def sequence_list(self):
return list(self.ordered_map.get(x) for x in self.ordered_map.keys())
@property
def is_empty(self):
return self.ordered_map.is_empty()
def floor(self, time):
return self.ordered_map.floor(time)
def event(self, index):
return self.ordered_map.get(index)
def floor_event(self, time):
floor_position = self.floor(time)
return self.event(floor_position) if floor_position else None
@property
def first(self):
return self.__first
@property
def last(self):
return self.__last
def add(self, new_members):
"""
Add any of a single Event or a list of Events.
Args:
new_members: Any of a single Event or a list of events
"""
if isinstance(new_members, list):
mem_set = new_members
inputt = [(e.time, e) for e in new_members]
else:
mem_set = [new_members]
inputt = [(new_members.time, new_members)]
for m in mem_set:
if self.ordered_map.has_reverse(m):
raise Exception('{0} already a member of sequence.'.format(m))
if not isinstance(m, Event):
raise Exception('{0} is not an event.'.format(m))
for i in inputt:
if i[1].time not in self.ordered_map:
self._add_successor_predecessor_maps(i[1])
else:
self._update_successor_predecessor_maps(i[1])
self.ordered_map.insert(i[0], i[1])
def remove(self, members):
"""
Remove any of a single Event or a list of Events already in the sequence.
Args:
members: Any of a single Event or a list of Events already in the sequence.
"""
if isinstance(members, list):
for member in members:
self.remove(member)
else:
if not self.ordered_map.has_reverse(members):
raise Exception('{0} not a member of sequence'.format(members))
self._remove_successor_predecessor_maps(members)
self.ordered_map.remove_key(self.ordered_map.reverse_get(members))
def move_event(self, event, new_time):
"""
Method to move event in sequence to a new time.
Args:
event: (Event) to move
new_time: the new time setting for the event
"""
if self.event(event.time) != event:
raise Exception('Given event at time {0} not in sequence'.format(event.time))
self.remove(event)
event.time = new_time
self.add(event)
def _add_successor_predecessor_maps(self, event):
fl_key = self.floor(event.time)
if fl_key:
a = self.event(fl_key)
b = self._successor[a] # could be None event is between a and b
self._successor[a] = event
self._successor[event] = b
self._predecessor[event] = a
if b:
self._predecessor[b] = event
else:
self.__last = event
else: # this event has to come first
if self.__first:
self._successor[event] = self.__first
self._predecessor[self.__first] = event
self._predecessor[event] = None
self.__first = event
else:
self.__first = self.__last = event
self._successor[event] = None
self._predecessor[event] = None
def _update_successor_predecessor_maps(self, event):
e = self.event(event.time)
self.remove(e)
self._add_successor_predecessor_maps(event)
pass
def _remove_successor_predecessor_maps(self, event):
a = self._predecessor[event]
b = self._successor[event]
del self._successor[event]
del self._predecessor[event]
if a:
self._successor[a] = b
else:
self.__first = b
if b:
self._predecessor[b] = a
else:
self.__last = a
def clear(self):
self.ordered_map.clear()
self._successor.clear()
self._predecessor.clear()
def successor(self, event):
return self._successor[event] if event in self._successor else None
def predecessor(self, event):
return self._predecessor[event] if event in self._predecessor else None
def __str__(self):
return ', '.join(str(x) for x in self.sequence_list)
def print_maps(self):
print('---------')
if self.__first:
print('first={0}'.format(self.__first))
else:
print('first=None')
if self.__first:
print('last={0}'.format(self.__last))
else:
print('last=None')
print('Successor:')
for i in self._successor.items():
print(' {0} --> {1}'.format(i[0].object if i[0] else 'None', i[1].object if i[1] else 'None'))
print('Predecessor:')
for i in self._predecessor.items():
print(' {0} --> {1}'.format(i[0].object if i[0] else 'None', i[1].object if i[1] else 'None'))
class TimeConversion(object):
"""
Time conversion algorithms.
1) Whole Time --> actual time
2) actual time --> Wholec Time
"""
def __init__(self, tempo_line, ts_line, max_position, pickup=Duration(0, 1)):
"""
Constructor.
Args:
tempo_line: (EventSequence) of TempoEvent's
ts_line: (EventSequence) of TimeSignatureEvent's
max_position: Position of end of whole note time
pickup: whole note time for a partial initial measure
Assumption:
tempo_line and ts_line cover position 0
Exceptions:
If pickup exceeds whole note time of the first time signature.
"""
self.tempo_line = tempo_line
self.ts_line = ts_line
self.__max_position = max_position
self.__pickup = pickup
if not isinstance(max_position, Position):
raise Exception('max_position argument must be Position not \'{0}\'.'.format(type(max_position)))
# check if the pickup exceeds the first TS
if self.ts_line is None or self.ts_line.is_empty or self.tempo_line is None or self.tempo_line.is_empty:
raise Exception('Time Signature and Tempo sequences must be non-empty for time conversions.')
if pickup.duration >= self.ts_line.event(0).object.beats_per_measure * \
self.ts_line.event(0).object.beat_duration.duration:
raise Exception(
'pickup exceeds timing based on first time signature {0}'.format(self.ts_line.event(0).object))
self._build_uniform_element_list()
self._build_lines()
self._build_search_trees()
self.__max_time = self.position_to_actual_time(self.max_position)
@property
def max_position(self):
return self.__max_position
@property
def pickup(self):
return self.__pickup
@property
def max_time(self):
return self.__max_time
def _build_uniform_element_list(self):
self.element_list = [Element(x.object, x.time) for x in self.tempo_line.sequence_list] + \
[Element(x.object, x.time) for x in self.ts_line.sequence_list]
self.element_list.sort(key=lambda p: p.position)
def _build_lines(self):
"""
Compute the actual time for the tempo and time signature elements.
"""
current_ts = None
current_tempo = None
current_at = 0
last_position = None
for element in self.element_list:
if current_ts and current_tempo:
translated_tempo = current_tempo.effective_tempo(current_ts.beat_duration)
current_at += (element.position - last_position).duration / \
(current_ts.beat_duration.duration * translated_tempo) * 60 * 1000
element.position_time = current_at
if element.is_tempo:
current_tempo = element.element
else:
current_ts = element.element
last_position = element.position
def _build_search_trees(self):
ts_mt_list = []
ts_time_list = []
tempo_mt_list = []
tempo_time_list = []
for element in self.element_list:
if element.is_tempo:
tempo_mt_list.append((element.position, element.element))
tempo_time_list.append((element.position_time, element.element))
else:
ts_mt_list.append((element.position, element.element))
ts_time_list.append((element.position_time, element.element))
self.ts_mt_map = OrderedMap(ts_mt_list) # whole note time --> TimeSignature
self.ts_time_map = OrderedMap(ts_time_list) # actual time --> TimeSignature
self.tempo_mt_map = OrderedMap(tempo_mt_list) # whole note time to Tempo
self.tempo_time_map = OrderedMap(tempo_time_list) # actual time to Tempo
# Build an ordered map, mapping BeatPosition --> time signature.
ts_bp_list = []
(position, ts) = ts_mt_list[0]
prior_pickup = 0
measure_tally = 0
if self.pickup.duration > 0:
num_beats = self.pickup.duration / ts.beat_duration.duration
ts_bp_list.append((BeatPosition(0, ts.beats_per_measure - num_beats), ts))
prior_pickup = num_beats
else:
ts_bp_list.append((BeatPosition(0, Fraction(0, 1)), ts))
for i in range(1, len(ts_mt_list)):
(position, ts) = ts_mt_list[i]
(prior_position, prior_ts) = ts_mt_list[i - 1]
num_beats = (position - prior_position).duration / prior_ts.beat_duration.duration - prior_pickup
num_measures = int(num_beats / prior_ts.beats_per_measure) + (1 if prior_pickup > 0 else 0)
measure_tally += num_measures
prior_pickup = 0
ts_bp_list.append((BeatPosition(measure_tally, 0), ts))
self.ts_bp_map = OrderedMap(ts_bp_list) # beat position --> TimeSignature
def position_to_actual_time(self, position):
"""
Convert a whole time position to it's actual time (in ms) from the beginning.
Args:
position: a Position in whole time.
Returns:
The actual time in ms for the position relative to the beginning.
Note: if the position exceeds max_position, we use max_position
"""
(tempo_mt_floor, tempo_element) = self.tempo_mt_map.floor_entry(position)
tempo_time = self.tempo_time_map.reverse_get(tempo_element)
(ts_mt_floor, ts_element) = self.ts_mt_map.floor_entry(position)
ts_time = self.ts_time_map.reverse_get(ts_element)
start_mt = max(tempo_mt_floor, ts_mt_floor)
start_time = max(tempo_time, ts_time)
# at this point, we have:
# start_mt: a whole time to start from
# start_time: the actual time to start from
# tempo_element: the current Tempo
# ts_element: the current TimeSignature
delta_mt = min(position, self.max_position) - start_mt
translated_tempo = tempo_element.effective_tempo(ts_element.beat_duration)
# time = music_time / (beat_duration * tempo)
delta_time = (delta_mt.duration / (ts_element.beat_duration.duration * translated_tempo)
if delta_mt > 0 else 0) * 60 * 1000
return start_time + delta_time
def actual_time_to_position(self, actual_time):
"""
Convert from an actual time (ms) position to a whole time Position
Args:
actual_time: the actual time (ms) of a position in the music
Returns:
the Position corresponding to the actual time.
Note: if actual_time exceeds max_time, we use max_time.
"""
(tempo_time_floor, tempo_element) = self.tempo_time_map.floor_entry(actual_time)
tempo_mt = self.tempo_mt_map.reverse_get(tempo_element)
(ts_time_floor, ts_element) = self.ts_time_map.floor_entry(actual_time)
ts_mt = self.ts_mt_map.reverse_get(ts_element)
start_mt = max(tempo_mt, ts_mt)
start_time = max(tempo_time_floor, ts_time_floor)
# at this point, we have:
# start_mt: a whole note time to start from
# start_time: the actual time to measure from
# tempo_element: the current Tempo
# ts_element: the current TimeSignature
delta_time = min(actual_time, self.max_time) - start_time
if not isinstance(delta_time, Fraction):
delta_time = Fraction.from_float(delta_time)
# musicTime = time * tempo * beat_duration
# Translate tempo using the time signature beat.
translated_tempo = tempo_element.effective_tempo(ts_element.beat_duration)
delta_mt = (delta_time * translated_tempo * ts_element.beat_duration.duration / (60 * 1000)) \
if delta_time > 0 else 0
return start_mt + delta_mt
def bp_to_position(self, beat_position):
"""
Method to convert a beat position to a whole note time position.
Args:
beat_position: BeatPosition object given measure, beat number
Returns:
the whole note time position for beat_position.
Exceptions:
for improper beat_position values
"""
(beginning_bp, ts_element) = self.ts_bp_map.floor_entry(beat_position)
if beat_position.beat_number >= ts_element.beats_per_measure:
raise Exception(
'Illegal beat asked for {0}, ts has 0-{1} beats per measure.'.format(beat_position.beat_number,
ts_element.beats_per_measure - 1))
ts_mt_floor = self.ts_mt_map.reverse_get(ts_element)
delta_mt = ((beat_position.measure_number - beginning_bp.measure_number) * ts_element.beats_per_measure +
beat_position.beat_number - beginning_bp.beat_number) * ts_element.beat_duration.duration
return Position(ts_mt_floor.position + delta_mt)
def position_to_bp(self, position):
"""
Method to convert a whole note time position to a beat position
Args:
position: the whole note time position
Returns:
the BeatPosition corresponding to the given position
"""
(ts_mt_floor, ts_element) = self.ts_mt_map.floor_entry(position)
ts_bp = self.ts_bp_map.reverse_get(ts_element)
num_beats = (position - ts_mt_floor).duration / ts_element.beat_duration.duration # - prior_pickup.duration
num_measures = int(num_beats / ts_element.beats_per_measure) # + (1 if prior_pickup.duration > 0 else 0)
residual_beats = num_beats - num_measures * ts_element.beats_per_measure
# add the measures and beats to ts_bp
beats = ts_bp.beat_number + residual_beats
measures = ts_bp.measure_number + num_measures
if beats >= ts_element.beats_per_measure:
beats -= ts_element.beats_per_measure
measures += 1
return BeatPosition(measures, beats)
