# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild from pkg_resources import parse_version from .kaitaistruct import __version__ as ks_version, KaitaiStruct, KaitaiStream, BytesIO import collections if parse_version(ks_version) < parse_version('0.7'): raise Exception("Incompatible Kaitai Struct Python API: 0.7 or later is required, but you have %s" % (ks_version)) class Bcd(KaitaiStruct): """BCD (Binary Coded Decimals) is a common way to encode integer numbers in a way that makes human-readable output somewhat simpler. In this encoding scheme, every decimal digit is encoded as either a single byte (8 bits), or a nibble (half of a byte, 4 bits). This obviously wastes a lot of bits, but it makes translation into human-readable string much easier than traditional binary-to-decimal conversion process, which includes lots of divisions by 10. For example, encoding integer 31337 in 8-digit, 8 bits per digit, big endian order of digits BCD format yields ``` 00 00 00 03 01 03 03 07 ``` Encoding the same integer as 8-digit, 4 bits per digit, little endian order BCD format would yield: ``` 73 31 30 00 ``` Using this type of encoding in Kaitai Struct is pretty straightforward: one calls for this type, specifying desired encoding parameters, and gets result using either `as_int` or `as_str` attributes. """ SEQ_FIELDS = ["digits"] def __init__(self, num_digits, bits_per_digit, is_le, _io, _parent=None, _root=None): self._io = _io self._parent = _parent self._root = _root if _root else self self.num_digits = num_digits self.bits_per_digit = bits_per_digit self.is_le = is_le self._debug = collections.defaultdict(dict) def _read(self): self._debug['digits']['start'] = self._io.pos() self.digits = [None] * (self.num_digits) for i in range(self.num_digits): if not 'arr' in self._debug['digits']: self._debug['digits']['arr'] = [] self._debug['digits']['arr'].append({'start': self._io.pos()}) _on = self.bits_per_digit if _on == 4: if not 'arr' in self._debug['digits']: self._debug['digits']['arr'] = [] self._debug['digits']['arr'].append({'start': self._io.pos()}) self.digits[i] = self._io.read_bits_int(4) self._debug['digits']['arr'][i]['end'] = self._io.pos() elif _on == 8: if not 'arr' in self._debug['digits']: self._debug['digits']['arr'] = [] self._debug['digits']['arr'].append({'start': self._io.pos()}) self.digits[i] = self._io.read_u1() self._debug['digits']['arr'][i]['end'] = self._io.pos() self._debug['digits']['arr'][i]['end'] = self._io.pos() self._debug['digits']['end'] = self._io.pos() @property def as_int(self): """Value of this BCD number as integer. Endianness would be selected based on `is_le` parameter given.""" if hasattr(self, '_m_as_int'): return self._m_as_int if hasattr(self, '_m_as_int') else None self._m_as_int = (self.as_int_le if self.is_le else self.as_int_be) return self._m_as_int if hasattr(self, '_m_as_int') else None @property def as_int_le(self): """Value of this BCD number as integer (treating digit order as little-endian).""" if hasattr(self, '_m_as_int_le'): return self._m_as_int_le if hasattr(self, '_m_as_int_le') else None self._m_as_int_le = (self.digits[0] + (0 if self.num_digits < 2 else ((self.digits[1] * 10) + (0 if self.num_digits < 3 else ((self.digits[2] * 100) + (0 if self.num_digits < 4 else ((self.digits[3] * 1000) + (0 if self.num_digits < 5 else ((self.digits[4] * 10000) + (0 if self.num_digits < 6 else ((self.digits[5] * 100000) + (0 if self.num_digits < 7 else ((self.digits[6] * 1000000) + (0 if self.num_digits < 8 else (self.digits[7] * 10000000))))))))))))))) return self._m_as_int_le if hasattr(self, '_m_as_int_le') else None @property def last_idx(self): """Index of last digit (0-based).""" if hasattr(self, '_m_last_idx'): return self._m_last_idx if hasattr(self, '_m_last_idx') else None self._m_last_idx = (self.num_digits - 1) return self._m_last_idx if hasattr(self, '_m_last_idx') else None @property def as_int_be(self): """Value of this BCD number as integer (treating digit order as big-endian).""" if hasattr(self, '_m_as_int_be'): return self._m_as_int_be if hasattr(self, '_m_as_int_be') else None self._m_as_int_be = (self.digits[self.last_idx] + (0 if self.num_digits < 2 else ((self.digits[(self.last_idx - 1)] * 10) + (0 if self.num_digits < 3 else ((self.digits[(self.last_idx - 2)] * 100) + (0 if self.num_digits < 4 else ((self.digits[(self.last_idx - 3)] * 1000) + (0 if self.num_digits < 5 else ((self.digits[(self.last_idx - 4)] * 10000) + (0 if self.num_digits < 6 else ((self.digits[(self.last_idx - 5)] * 100000) + (0 if self.num_digits < 7 else ((self.digits[(self.last_idx - 6)] * 1000000) + (0 if self.num_digits < 8 else (self.digits[(self.last_idx - 7)] * 10000000))))))))))))))) return self._m_as_int_be if hasattr(self, '_m_as_int_be') else None