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# ADN DMR Peer Server - DMR BPTC embedded LC (dmr_utils3 adapter)
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# Copyright (C) 2026 Rodrigo Pérez, CE5RPY <ce5rpy@qmd.cl>
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"""Corrected embedded-LC BPTC encoder (drop-in for ``dmr_utils3.bptc.encode_emblc``)."""
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from __future__ import annotations
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from bitarray import bitarray
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from dmr_utils3 import crc, hamming
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def encode_emblc(lc: bytes) -> dict[int, bitarray]:
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"""Encode a 9-byte embedded LC into burst B–E fragment dicts {1..4: bitarray}.
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Upstream ``dmr_utils3.bptc.encode_emblc`` uses ``_binlc[24]`` twice in segment D row 2
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instead of ``_binlc[25]``, which can corrupt one bit (e.g. Talker Alias ``Rodrigo`` →
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``Rodrigg``). This copy matches upstream except for that index, so decode on radios and
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``dmr_utils3.bptc.decode_emblc`` stay aligned.
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Use this everywhere ADN generates embedded LC (bridge group LC, TA overlay, parrot).
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"""
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_csum = crc.csum5(lc)
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_binlc = bitarray(endian="big")
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_binlc.frombytes(lc)
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_binlc.insert(32, _csum[0])
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_binlc.insert(43, _csum[1])
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_binlc.insert(54, _csum[2])
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_binlc.insert(65, _csum[3])
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_binlc.insert(76, _csum[4])
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for index in range(0, 112, 16):
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for hindex, hbit in zip(
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range(index + 11, index + 16), hamming.enc_16114(_binlc[index:index + 11])
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):
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_binlc.insert(hindex, hbit)
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for index in range(0, 16):
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_binlc.insert(
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index + 112,
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_binlc[index] ^ _binlc[index + 16] ^ _binlc[index + 32] ^ _binlc[index + 48]
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^ _binlc[index + 64] ^ _binlc[index + 80] ^ _binlc[index + 96],
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)
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def _seg(rows: tuple[tuple[int, ...], ...]) -> bitarray:
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out = bitarray(endian="big")
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for row in rows:
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out.extend([_binlc[i] for i in row])
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return out
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emblc_b = _seg((
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(0, 16, 32, 48, 64, 80, 96, 112),
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(1, 17, 33, 49, 65, 81, 97, 113),
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(2, 18, 34, 50, 66, 82, 98, 114),
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(3, 19, 35, 51, 67, 83, 99, 115),
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))
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emblc_c = _seg((
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(4, 20, 36, 52, 68, 84, 100, 116),
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(5, 21, 37, 53, 69, 85, 101, 117),
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(6, 22, 38, 54, 70, 86, 102, 118),
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(7, 23, 39, 55, 71, 87, 103, 119),
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))
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emblc_d = _seg((
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(8, 24, 40, 56, 72, 88, 104, 120),
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(9, 25, 41, 57, 73, 89, 105, 121), # fixed: bit 25 (dmr_utils3 wrongly uses 24)
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(10, 26, 42, 58, 74, 90, 106, 122),
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(11, 27, 43, 59, 75, 91, 107, 123),
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))
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emblc_e = _seg((
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(12, 28, 44, 60, 76, 92, 108, 124),
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(13, 29, 45, 61, 77, 93, 109, 125),
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(14, 30, 46, 62, 78, 94, 110, 126),
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(15, 31, 47, 63, 79, 95, 111, 127),
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))
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return {1: emblc_b, 2: emblc_c, 3: emblc_d, 4: emblc_e}
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