diff --git a/bptc19696.py b/bptc19696.py index ac0902c..711dd7a 100755 --- a/bptc19696.py +++ b/bptc19696.py @@ -35,24 +35,24 @@ mod_181_index = ( 195, 180, 165, 150, 135, 120, 105, 90, 75, 60, 45, 30, 15) # Converts a DMR frame using 98-68-98 (info-sync/EMB-info) into 196 bit array -def dec_get_binary_19696(_data): +def to_binary_19696(_data): _bits = bitarray(endian='big') _bits.frombytes(_data) return _bits[:98] + _bits[-98:] # Applies interleave indecies de-interleave 196 bit array -def dec_deinterleave_19696(_data): +def deinterleave_19696(_data): deint = bitarray(196) for index in xrange(196): deint[index] = _data[mod_181_index[index]] # the real math is slower: deint[index] = _data[(index * 181) % 196] return deint # Applies BTPC error detection/correction routines (INCOMPLETE) -def dec_error_check_19696(_data): +def error_check_19696(_data): checked = bitarray(196) # Returns useable LC data - 9 bytes info + 3 bytes RS(12,9) ECC -def dec_get_data_19696(_data): +def to_bytes_19696(_data): databits = _data[4:12]+_data[16:27]+_data[31:42]+_data[46:57]+_data[61:72]+_data[76:87]+_data[91:102]+_data[106:117]+_data[121:132] return databits.tobytes() @@ -77,10 +77,10 @@ if __name__ == '__main__': data = data[20:53] t0 = time() - bin_data = dec_get_binary_19696(data) - deint_data = dec_deinterleave_19696(bin_data) + bin_data = to_binary_19696(data) + deint_data = deinterleave_19696(bin_data) #err_corrected = dec_error_check_19696(deint_data) - ext_data = dec_get_data_19696(deint_data) + ext_data = to_bytes_19696(deint_data) t1 = time() print('TIME: ', t1-t0, '\n') diff --git a/hamming.py b/hamming.py index def439f..f363c27 100755 --- a/hamming.py +++ b/hamming.py @@ -101,13 +101,64 @@ def dec_hamming_1393(_data): if n == 0x0f: _data[0] = not _data[0]; return (_data, True) if n == 0x07: _data[1] = not _data[1]; return (_data, True) - if n == 0x0b: _data[2] = not _data[2]; return (_data, True) - if n == 0x03: _data[3] = not _data[3]; return (_data, True) - if n == 0x0d: _data[4] = not _data[4]; return (_data, True) - if n == 0x05: _data[5] = not _data[5]; return (_data, True) - if n == 0x09: _data[6] = not _data[6]; return (_data, True) - if n == 0x0e: _data[7] = not _data[7]; return (_data, True) - if n == 0x06: _data[8] = not _data[8]; return (_data, True) + if n == 0x0e: _data[2] = not _data[2]; return (_data, True) + if n == 0x05: _data[3] = not _data[3]; return (_data, True) + if n == 0x0a: _data[4] = not _data[4]; return (_data, True) + if n == 0x0d: _data[5] = not _data[5]; return (_data, True) + if n == 0x03: _data[6] = not _data[6]; return (_data, True) + if n == 0x06: _data[7] = not _data[7]; return (_data, True) + if n == 0x0c: _data[8] = not _data[8]; return (_data, True) + + return (_data, False) + +#------------------------------------------------------------------------------ +# Hamming 16,11,4 routines +#------------------------------------------------------------------------------ + +# ENCODER - returns a bitarray object containing the hamming checksums +def enc_hamming_16114(_data): + csum = bitarray(5) + csum[0] = _data[0] ^ _data[1] ^ _data[2] ^ _data[3] ^ _data[5] ^ _data[7] ^ _data[8] + csum[1] = _data[1] ^ _data[2] ^ _data[3] ^ _data[4] ^ _data[6] ^ _data[8] ^ _data[9] + csum[2] = _data[2] ^ _data[3] ^ _data[4] ^ _data[5] ^ _data[7] ^ _data[9] ^ _data[10] + csum[3] = _data[0] ^ _data[1] ^ _data[2] ^ _data[4] ^ _data[6] ^ _data[7] ^ _data[10] + csum[4] = _data[0] ^ _data[2] ^ _data[5] ^ _data[6] ^ _data[8] ^ _data[9] ^ _data[10] + return csum + +# DECODER - Returns a tuple of (decoded data, True if an error was corrected) +def dec_hamming_16114(_data): + chk0 = _data[0] ^ _data[1] ^ _data[2] ^ _data[3] ^ _data[5] ^ _data[7] ^ _data[8] + chk1 = _data[1] ^ _data[2] ^ _data[3] ^ _data[4] ^ _data[6] ^ _data[8] ^ _data[9] + chk2 = _data[2] ^ _data[3] ^ _data[4] ^ _data[5] ^ _data[7] ^ _data[9] ^ _data[10] + chk3 = _data[0] ^ _data[1] ^ _data[2] ^ _data[4] ^ _data[6] ^ _data[7] ^ _data[10] + chk4 = _data[0] ^ _data[2] ^ _data[5] ^ _data[6] ^ _data[8] ^ _data[9] ^ _data[10] + + n = 0 + error = False + + n |= 0x01 if chk0 != _data[11] else 0x00 + n |= 0x02 if chk1 != _data[12] else 0x00 + n |= 0x04 if chk2 != _data[13] else 0x00 + n |= 0x08 if chk3 != _data[14] else 0x00 + n |= 0x10 if chk4 != _data[15] else 0x00 + + if n == 0x01: _data[11] = not _data[11]; return (_data, True) + if n == 0x02: _data[12] = not _data[12]; return (_data, True) + if n == 0x04: _data[13] = not _data[13]; return (_data, True) + if n == 0x08: _data[14] = not _data[14]; return (_data, True) + if n == 0x10: _data[15] = not _data[15]; return (_data, True) + + if n == 0x19: _data[0] = not _data[0]; return (_data, True) + if n == 0x0b: _data[1] = not _data[1]; return (_data, True) + if n == 0x1f: _data[2] = not _data[2]; return (_data, True) + if n == 0x07: _data[3] = not _data[3]; return (_data, True) + if n == 0x0e: _data[4] = not _data[4]; return (_data, True) + if n == 0x15: _data[5] = not _data[5]; return (_data, True) + if n == 0x1a: _data[6] = not _data[6]; return (_data, True) + if n == 0x0d: _data[7] = not _data[7]; return (_data, True) + if n == 0x13: _data[8] = not _data[8]; return (_data, True) + if n == 0x16: _data[9] = not _data[9]; return (_data, True) + if n == 0x1c: _data[10] = not _data[10]; return (_data, True) return (_data, False) @@ -119,21 +170,22 @@ def dec_hamming_1393(_data): if __name__ == '__main__': # Validation Example - - # Good - _data = bitarray('0000000000000000000100000011101000000000000000000000110001110011000000100100111110011010110111100101111001011010110101101100010110100110000110000111100111010011101101000010101001110000100101010100') - # Bad - _data = bitarray('0000000000000000000110000011101000000000000000000000110001110011000000100100111110011010110111100101111001011010110101101100010110100110000110000111100111010011101101000010101001110000100101010100') + good_data_15113 = bitarray('0000000000000000000100000011101000000000000000000000110001110011000000100100111110011010110111100101111001011010110101101100010110100110000110000111100111010011101101000010101001110000100101010100') + bad_data_15113 = bitarray('0000000000000000000110000011101000000000000000000000110001110011000000100100111110011010110111100101111001011010110101101100010110100110000110000111100111010011101101000010101001110000100101010100') - rows = (_data[1:16],_data[16:31],_data[31:46],_data[46:61],_data[61:76],_data[76:91],_data[91:106],_data[106:121],_data[121:136]) - - for row in rows: - print('original data:', row[0:11], 'original parity:', row[11:15]) + def check_15113(_data): + rows = (_data[1:16],_data[16:31],_data[31:46],_data[46:61],_data[61:76],_data[76:91],_data[91:106],_data[106:121],_data[121:136]) + print('Processing New Integrity Check') + for row in rows: + print('original data:', row[0:11], 'original parity:', row[11:15]) - hamming_dec = dec_hamming_15113(row[0:15]) - code = hamming_dec[0] - error = hamming_dec[1] + hamming_dec = dec_hamming_15113(row[0:15]) + code = hamming_dec[0] + error = hamming_dec[1] - print('return data: ', code[0:11], 'return parity: ', code[11:15], 'return error:', error) - print('calculated parity:', enc_hamming_15113(row[0:11])) - print() \ No newline at end of file + print('\tDECODE: data: ', code[0:11], 'parity: ', code[11:15], 'error:', error) + print('\tENCODE: calculated parity:', enc_hamming_15113(row[0:11])) + print() + + check_15113(good_data_15113) + check_15113(bad_data_15113) \ No newline at end of file