Philip Guzman
68 lines
2.0 KiB
Python
68 lines
2.0 KiB
Python
from pathlib import Path
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from typing import Dict, Iterator, Optional, Tuple
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from serato_doctor.models.database import DatabaseTrack, SeratoDatabase
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TEXT_FIELDS = {
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b"tsng": "title",
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b"tart": "artist",
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b"talb": "album",
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b"tgen": "genre",
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}
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def iter_records(data: bytes) -> Iterator[Tuple[bytes, bytes]]:
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"""Yield complete big-endian tag-length-value records."""
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offset = 0
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while offset + 8 <= len(data):
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tag = data[offset : offset + 4]
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length = int.from_bytes(data[offset + 4 : offset + 8], "big")
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payload_start = offset + 8
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payload_end = payload_start + length
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if payload_end > len(data):
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break
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yield tag, data[payload_start:payload_end]
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offset = payload_end
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def decode_text(payload: bytes) -> Optional[str]:
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value = payload.decode("utf-16-be", errors="ignore").strip("\x00").strip()
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return value or None
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def normalize_database_path(value: str) -> Path:
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if value.startswith(("Users/", "Volumes/")):
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value = "/" + value
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return Path(value)
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def parse_track(payload: bytes) -> Optional[DatabaseTrack]:
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fields: Dict[str, Optional[str]] = {}
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path = None
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for tag, value in iter_records(payload):
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if tag == b"pfil":
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decoded_path = decode_text(value)
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if decoded_path:
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path = normalize_database_path(decoded_path)
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elif tag in TEXT_FIELDS:
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fields[TEXT_FIELDS[tag]] = decode_text(value)
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if path is None:
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return None
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return DatabaseTrack(path=path, filename=path.name, **fields)
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def parse_database(database_path: Path) -> SeratoDatabase:
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data = database_path.read_bytes()
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version = None
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tracks = []
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for tag, payload in iter_records(data):
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if tag == b"vrsn":
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version = decode_text(payload)
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elif tag == b"otrk":
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track = parse_track(payload)
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if track is not None:
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tracks.append(track)
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return SeratoDatabase(database_path, version, tuple(tracks))
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