khodowany
96 lines
4.4 KiB
Python
96 lines
4.4 KiB
Python
from __future__ import annotations
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import dataclasses
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import fractions
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import pathlib
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import types
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import generator.model
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import generator.musicxml
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@dataclasses.dataclass(frozen=True)
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class Event:
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onset: fractions.Fraction
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duration: fractions.Fraction
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sounding: bool
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written_type: str
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dots: int = 0
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beams: tuple[tuple[int, str], ...] = ()
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continuation: bool = False
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@dataclasses.dataclass(frozen=True)
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class Bar:
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events: tuple[Event, ...]
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length: fractions.Fraction
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def attacks(self) -> tuple[fractions.Fraction, ...]:
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return tuple(e.onset for e in self.events if e.sounding and not e.continuation)
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def beat(self, number: int) -> tuple:
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return tuple((max(e.onset, number) - number, min(e.onset + e.duration, number + 1) - max(e.onset, number), e.sounding, e.continuation or e.onset < number) for e in self.events if e.onset < number + 1 and e.onset + e.duration > number)
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@dataclasses.dataclass(frozen=True)
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class Snippet:
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id: str
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meter: str
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bars: tuple[Bar, ...]
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@dataclasses.dataclass(frozen=True, init=False)
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class Library:
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snippets: types.MappingProxyType
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def __init__(self, snippets: tuple[Snippet, ...]):
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grouped = {}
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identities = set()
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for snippet in sorted(snippets, key=lambda s: s.id):
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if snippet.id in identities:
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raise ValueError(f'duplicate rhythm identity: {snippet.id}')
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identities.add(snippet.id)
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grouped.setdefault(snippet.meter, []).append(snippet)
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object.__setattr__(self, 'snippets', types.MappingProxyType({meter: tuple(values) for meter, values in grouped.items()}))
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def for_meter(self, meter: str) -> tuple[Snippet, ...]:
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if meter not in ('2/4', '3/4', '4/4', '5/4') or meter not in self.snippets:
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raise ValueError(f'accompaniment requires rhythm snippets for {meter}; supported meters are 2/4, 3/4, 4/4, and 5/4')
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return self.snippets[meter]
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def read_snippet(path: pathlib.Path, identifier: str) -> Snippet:
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document = generator.musicxml.load_musicxml(path)
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staff = document['staves'][0]
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if len(staff['measures']) not in (1, 2) or staff.get('tuplets'):
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raise ValueError(f'{path}: rhythm snippets require one or two bars without tuplets')
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meter = staff['measures'][0]['time_signature']
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bars = []
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for measure in staff['measures']:
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length = generator.model.fraction(measure['duration'])
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if measure['time_signature'] != meter or length != generator.model.meter_length(measure['meter']):
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raise ValueError(f'{path}, measure {measure["number"]}: rhythm bars must be complete and use one meter')
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if len(measure['voices']) != 1 or any('meter' in a for a in measure.get('attributes', [])):
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raise ValueError(f'{path}: rhythm snippets require one voice without meter changes')
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events = []
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cursor = fractions.Fraction()
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for note in measure['voices'][0]['notes']:
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onset, duration = generator.model.fraction(note['onset']), generator.model.fraction(note['duration'])
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if onset != cursor or duration <= 0 or note.get('grace') or note['kind'] not in ('note', 'rest') or note.get('tremolo'):
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raise ValueError(f'{path}, measure {measure["number"]}: rhythm events must fill the bar sequentially')
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if 'ratio' in note['written']:
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raise ValueError(f'{path}, measure {measure["number"]}: rhythm snippets do not support time modifications')
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events.append(Event(onset, duration, note['kind'] == 'note', note['written']['type'], note['written'].get('dots', 0), tuple((b['level'], b['type']) for b in note.get('beams', [])), any('tie_from' in p for p in note['pitches'])))
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cursor += duration
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if cursor != length:
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raise ValueError(f'{path}: rhythm events do not fill the bar')
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bars.append(Bar(tuple(events), length))
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return Snippet(identifier, meter, tuple(bars))
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def load_library(root: pathlib.Path) -> Library:
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if not root.is_dir():
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raise ValueError(f'{root}: rhythm library not found')
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snippets = []
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for path in sorted(root.rglob('*.xml')):
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relative = path.relative_to(root)
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if len(relative.parts) != 3 or relative.parts[0] not in ('2_4', '3_4', '4_4', '5_4') or relative.parts[1] not in ('1', '2', '3'):
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raise ValueError(f'{path}: rhythm sources belong under meter/series')
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snippet = read_snippet(path, relative.as_posix())
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if snippet.meter != relative.parts[0].replace('_', '/'):
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raise ValueError(f'{path}: rhythm meter disagrees with its directory')
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snippets.append(snippet)
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if not snippets:
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raise ValueError(f'{root}: rhythm library is empty')
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return Library(tuple(snippets))
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