annotate env/lib/python3.7/site-packages/chardet/codingstatemachine.py @ 0:26e78fe6e8c4 draft

"planemo upload commit c699937486c35866861690329de38ec1a5d9f783"
author shellac
date Sat, 02 May 2020 07:14:21 -0400
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1 ######################## BEGIN LICENSE BLOCK ########################
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2 # The Original Code is mozilla.org code.
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3 #
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4 # The Initial Developer of the Original Code is
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5 # Netscape Communications Corporation.
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6 # Portions created by the Initial Developer are Copyright (C) 1998
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7 # the Initial Developer. All Rights Reserved.
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8 #
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9 # Contributor(s):
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10 # Mark Pilgrim - port to Python
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11 #
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12 # This library is free software; you can redistribute it and/or
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13 # modify it under the terms of the GNU Lesser General Public
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14 # License as published by the Free Software Foundation; either
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15 # version 2.1 of the License, or (at your option) any later version.
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16 #
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17 # This library is distributed in the hope that it will be useful,
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18 # but WITHOUT ANY WARRANTY; without even the implied warranty of
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19 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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20 # Lesser General Public License for more details.
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21 #
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22 # You should have received a copy of the GNU Lesser General Public
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23 # License along with this library; if not, write to the Free Software
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24 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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25 # 02110-1301 USA
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26 ######################### END LICENSE BLOCK #########################
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27
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28 import logging
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29
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30 from .enums import MachineState
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31
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32
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33 class CodingStateMachine(object):
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34 """
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35 A state machine to verify a byte sequence for a particular encoding. For
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36 each byte the detector receives, it will feed that byte to every active
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37 state machine available, one byte at a time. The state machine changes its
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38 state based on its previous state and the byte it receives. There are 3
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39 states in a state machine that are of interest to an auto-detector:
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40
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41 START state: This is the state to start with, or a legal byte sequence
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42 (i.e. a valid code point) for character has been identified.
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43
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44 ME state: This indicates that the state machine identified a byte sequence
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45 that is specific to the charset it is designed for and that
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46 there is no other possible encoding which can contain this byte
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47 sequence. This will to lead to an immediate positive answer for
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48 the detector.
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49
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50 ERROR state: This indicates the state machine identified an illegal byte
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51 sequence for that encoding. This will lead to an immediate
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52 negative answer for this encoding. Detector will exclude this
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53 encoding from consideration from here on.
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54 """
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55 def __init__(self, sm):
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56 self._model = sm
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57 self._curr_byte_pos = 0
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58 self._curr_char_len = 0
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59 self._curr_state = None
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60 self.logger = logging.getLogger(__name__)
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61 self.reset()
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62
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63 def reset(self):
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64 self._curr_state = MachineState.START
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65
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66 def next_state(self, c):
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67 # for each byte we get its class
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68 # if it is first byte, we also get byte length
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69 byte_class = self._model['class_table'][c]
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70 if self._curr_state == MachineState.START:
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71 self._curr_byte_pos = 0
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72 self._curr_char_len = self._model['char_len_table'][byte_class]
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73 # from byte's class and state_table, we get its next state
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74 curr_state = (self._curr_state * self._model['class_factor']
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75 + byte_class)
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76 self._curr_state = self._model['state_table'][curr_state]
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77 self._curr_byte_pos += 1
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78 return self._curr_state
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79
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80 def get_current_charlen(self):
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81 return self._curr_char_len
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82
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83 def get_coding_state_machine(self):
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84 return self._model['name']
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85
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86 @property
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87 def language(self):
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88 return self._model['language']