a little endian version of the BitField
| 61 | |
| 62 | |
| 63 | class LEBitField(BitField): |
| 64 | """ |
| 65 | a little endian version of the BitField |
| 66 | """ |
| 67 | |
| 68 | def _check_field_type(self, pkt, index): |
| 69 | """ |
| 70 | check if the field addressed by given index relative to this field |
| 71 | shares type of this field so we can catch a mix of LEBitField |
| 72 | and BitField/other types |
| 73 | """ |
| 74 | my_idx = pkt.fields_desc.index(self) |
| 75 | try: |
| 76 | next_field = pkt.fields_desc[my_idx + index] |
| 77 | if type(next_field) is not LEBitField and \ |
| 78 | next_field.__class__.__base__ is not LEBitField: |
| 79 | raise LEBitFieldSequenceException('field after field {} must ' |
| 80 | 'be of type LEBitField or ' |
| 81 | 'derived classes'.format(self.name)) # noqa: E501 |
| 82 | except IndexError: |
| 83 | # no more fields -> error |
| 84 | raise LEBitFieldSequenceException('Missing further LEBitField ' |
| 85 | 'based fields after field ' |
| 86 | '{} '.format(self.name)) |
| 87 | |
| 88 | def addfield(self, pkt, s, val): |
| 89 | """ |
| 90 | |
| 91 | :param pkt: packet instance the raw string s and field belongs to |
| 92 | :param s: raw string representing the frame |
| 93 | :param val: value |
| 94 | :return: final raw string, tuple (s, bitsdone, data) if in between bit field # noqa: E501 |
| 95 | |
| 96 | as we don't know the final size of the full bitfield we need to accumulate the data. # noqa: E501 |
| 97 | if we reach a field that ends at a octet boundary, we build the whole string # noqa: E501 |
| 98 | |
| 99 | """ |
| 100 | if type(s) is tuple and len(s) == 4: |
| 101 | s, bitsdone, data, _ = s |
| 102 | self._check_field_type(pkt, -1) |
| 103 | else: |
| 104 | # this is the first bit field in the set |
| 105 | bitsdone = 0 |
| 106 | data = [] |
| 107 | |
| 108 | bitsdone += self.size |
| 109 | data.append((self.size, self.i2m(pkt, val))) |
| 110 | |
| 111 | if bitsdone % 8: |
| 112 | # somewhere in between bit 0 .. 7 - next field should add more bits... # noqa: E501 |
| 113 | self._check_field_type(pkt, 1) |
| 114 | return s, bitsdone, data, type(LEBitField) |
| 115 | else: |
| 116 | data.reverse() |
| 117 | octet = 0 |
| 118 | remaining_len = 8 |
| 119 | octets = bytearray() |
| 120 | for size, val in data: |
no outgoing calls
no test coverage detected