33 lines
1.1 KiB
Python
33 lines
1.1 KiB
Python
import struct
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from app.fit.crc import fit_crc
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def make_fit(data_records: bytes, *, header_size: int = 14) -> bytes:
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if header_size not in {12, 14}:
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raise ValueError(header_size)
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header = bytearray(header_size)
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header[0] = header_size
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header[1] = 0x20
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struct.pack_into("<H", header, 2, 0x0100)
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struct.pack_into("<I", header, 4, len(data_records))
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header[8:12] = b".FIT"
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if header_size == 14:
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struct.pack_into("<H", header, 12, fit_crc(header[:12]))
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body = header + data_records
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return bytes(body + struct.pack("<H", fit_crc(body)))
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def definition(local: int, global_num: int, fields: list[tuple[int, int, int]], *, endian: str = "<") -> bytes:
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architecture = 1 if endian == ">" else 0
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payload = bytearray([0, architecture])
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payload.extend(struct.pack(f"{endian}H", global_num))
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payload.append(len(fields))
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for num, size, base_type in fields:
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payload.extend(bytes([num, size, base_type]))
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return bytes([0x40 | local]) + bytes(payload)
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def data(local: int, payload: bytes) -> bytes:
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return bytes([local]) + payload
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