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# MIT License |
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# |
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# Copyright (c) 2017 Matt Boyer |
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# |
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# Permission is hereby granted, free of charge, to any person obtaining a copy |
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# of this software and associated documentation files (the "Software"), to deal |
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# in the Software without restriction, including without limitation the rights |
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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# copies of the Software, and to permit persons to whom the Software is |
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# furnished to do so, subject to the following conditions: |
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# |
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# The above copyright notice and this permission notice shall be included in |
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# all copies or substantial portions of the Software. |
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# |
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
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# SOFTWARE. |
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import struct |
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from .utils import decode_twos_complement |
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class MalformedField(Exception): |
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pass |
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View Code Duplication |
class Field(object): |
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def __init__(self, idx, serial_type, serial_bytes): |
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self._index = idx |
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self._type = serial_type |
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self._bytes = serial_bytes |
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self._value = None |
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self._parse() |
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def _check_length(self, expected_length): |
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if len(self) != expected_length: |
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raise MalformedField |
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# TODO Raise a specific exception when bad bytes are encountered for the |
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# fields and then use this to weed out bad freeblock records |
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def _parse(self): |
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if self._type == 0: |
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self._value = None |
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# Integer types |
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elif self._type == 1: |
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self._check_length(1) |
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self._value = decode_twos_complement(bytes(self)[0:1], 8) |
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elif self._type == 2: |
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self._check_length(2) |
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self._value = decode_twos_complement(bytes(self)[0:2], 16) |
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elif self._type == 3: |
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self._check_length(3) |
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self._value = decode_twos_complement(bytes(self)[0:3], 24) |
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elif self._type == 4: |
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self._check_length(4) |
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self._value = decode_twos_complement(bytes(self)[0:4], 32) |
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elif self._type == 5: |
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self._check_length(6) |
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self._value = decode_twos_complement(bytes(self)[0:6], 48) |
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elif self._type == 6: |
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self._check_length(8) |
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self._value = decode_twos_complement(bytes(self)[0:8], 64) |
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elif self._type == 7: |
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self._value = struct.unpack(r'>d', bytes(self)[0:8])[0] |
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elif self._type == 8: |
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self._value = 0 |
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elif self._type == 9: |
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self._value = 1 |
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elif self._type >= 13 and (1 == self._type % 2): |
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try: |
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self._value = bytes(self).decode('utf-8') |
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except UnicodeDecodeError as ex: |
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raise MalformedField from ex |
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elif self._type >= 12 and (0 == self._type % 2): |
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self._value = bytes(self) |
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def __bytes__(self): |
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return self._bytes |
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def __repr__(self): |
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return "<Field {}: {} ({} bytes)>".format( |
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self._index, self._value, len(bytes(self)) |
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) |
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def __len__(self): |
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return len(bytes(self)) |
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@property |
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def index(self): |
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return self._index |
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@property |
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def value(self): |
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return self._value |
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@property |
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def serial_type(self): |
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return self._type |
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mattboyer /
sqbrite
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