mirror of
https://github.com/jbowdre/phpIPAM-for-vRA8.git
synced 2024-11-30 10:52:17 +00:00
293 lines
14 KiB
Python
293 lines
14 KiB
Python
|
######################## BEGIN LICENSE BLOCK ########################
|
||
|
|
# The Original Code is Mozilla Universal charset detector code.
|
||
|
|
#
|
||
|
|
# The Initial Developer of the Original Code is
|
||
|
|
# Shy Shalom
|
||
|
|
# Portions created by the Initial Developer are Copyright (C) 2005
|
||
|
|
# the Initial Developer. All Rights Reserved.
|
||
|
|
#
|
||
|
|
# Contributor(s):
|
||
|
|
# Mark Pilgrim - port to Python
|
||
|
|
#
|
||
|
|
# This library is free software; you can redistribute it and/or
|
||
|
|
# modify it under the terms of the GNU Lesser General Public
|
||
|
|
# License as published by the Free Software Foundation; either
|
||
|
|
# version 2.1 of the License, or (at your option) any later version.
|
||
|
|
#
|
||
|
|
# This library is distributed in the hope that it will be useful,
|
||
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
|
|
# Lesser General Public License for more details.
|
||
|
|
#
|
||
|
|
# You should have received a copy of the GNU Lesser General Public
|
||
|
|
# License along with this library; if not, write to the Free Software
|
||
|
|
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
|
||
|
|
# 02110-1301 USA
|
||
|
|
######################### END LICENSE BLOCK #########################
|
||
|
|
|
||
|
|
from .charsetprober import CharSetProber
|
||
|
|
from .enums import ProbingState
|
||
|
|
|
||
|
|
# This prober doesn't actually recognize a language or a charset.
|
||
|
|
# It is a helper prober for the use of the Hebrew model probers
|
||
|
|
|
||
|
|
### General ideas of the Hebrew charset recognition ###
|
||
|
|
#
|
||
|
|
# Four main charsets exist in Hebrew:
|
||
|
|
# "ISO-8859-8" - Visual Hebrew
|
||
|
|
# "windows-1255" - Logical Hebrew
|
||
|
|
# "ISO-8859-8-I" - Logical Hebrew
|
||
|
|
# "x-mac-hebrew" - ?? Logical Hebrew ??
|
||
|
|
#
|
||
|
|
# Both "ISO" charsets use a completely identical set of code points, whereas
|
||
|
|
# "windows-1255" and "x-mac-hebrew" are two different proper supersets of
|
||
|
|
# these code points. windows-1255 defines additional characters in the range
|
||
|
|
# 0x80-0x9F as some misc punctuation marks as well as some Hebrew-specific
|
||
|
|
# diacritics and additional 'Yiddish' ligature letters in the range 0xc0-0xd6.
|
||
|
|
# x-mac-hebrew defines similar additional code points but with a different
|
||
|
|
# mapping.
|
||
|
|
#
|
||
|
|
# As far as an average Hebrew text with no diacritics is concerned, all four
|
||
|
|
# charsets are identical with respect to code points. Meaning that for the
|
||
|
|
# main Hebrew alphabet, all four map the same values to all 27 Hebrew letters
|
||
|
|
# (including final letters).
|
||
|
|
#
|
||
|
|
# The dominant difference between these charsets is their directionality.
|
||
|
|
# "Visual" directionality means that the text is ordered as if the renderer is
|
||
|
|
# not aware of a BIDI rendering algorithm. The renderer sees the text and
|
||
|
|
# draws it from left to right. The text itself when ordered naturally is read
|
||
|
|
# backwards. A buffer of Visual Hebrew generally looks like so:
|
||
|
|
# "[last word of first line spelled backwards] [whole line ordered backwards
|
||
|
|
# and spelled backwards] [first word of first line spelled backwards]
|
||
|
|
# [end of line] [last word of second line] ... etc' "
|
||
|
|
# adding punctuation marks, numbers and English text to visual text is
|
||
|
|
# naturally also "visual" and from left to right.
|
||
|
|
#
|
||
|
|
# "Logical" directionality means the text is ordered "naturally" according to
|
||
|
|
# the order it is read. It is the responsibility of the renderer to display
|
||
|
|
# the text from right to left. A BIDI algorithm is used to place general
|
||
|
|
# punctuation marks, numbers and English text in the text.
|
||
|
|
#
|
||
|
|
# Texts in x-mac-hebrew are almost impossible to find on the Internet. From
|
||
|
|
# what little evidence I could find, it seems that its general directionality
|
||
|
|
# is Logical.
|
||
|
|
#
|
||
|
|
# To sum up all of the above, the Hebrew probing mechanism knows about two
|
||
|
|
# charsets:
|
||
|
|
# Visual Hebrew - "ISO-8859-8" - backwards text - Words and sentences are
|
||
|
|
# backwards while line order is natural. For charset recognition purposes
|
||
|
|
# the line order is unimportant (In fact, for this implementation, even
|
||
|
|
# word order is unimportant).
|
||
|
|
# Logical Hebrew - "windows-1255" - normal, naturally ordered text.
|
||
|
|
#
|
||
|
|
# "ISO-8859-8-I" is a subset of windows-1255 and doesn't need to be
|
||
|
|
# specifically identified.
|
||
|
|
# "x-mac-hebrew" is also identified as windows-1255. A text in x-mac-hebrew
|
||
|
|
# that contain special punctuation marks or diacritics is displayed with
|
||
|
|
# some unconverted characters showing as question marks. This problem might
|
||
|
|
# be corrected using another model prober for x-mac-hebrew. Due to the fact
|
||
|
|
# that x-mac-hebrew texts are so rare, writing another model prober isn't
|
||
|
|
# worth the effort and performance hit.
|
||
|
|
#
|
||
|
|
#### The Prober ####
|
||
|
|
#
|
||
|
|
# The prober is divided between two SBCharSetProbers and a HebrewProber,
|
||
|
|
# all of which are managed, created, fed data, inquired and deleted by the
|
||
|
|
# SBCSGroupProber. The two SBCharSetProbers identify that the text is in
|
||
|
|
# fact some kind of Hebrew, Logical or Visual. The final decision about which
|
||
|
|
# one is it is made by the HebrewProber by combining final-letter scores
|
||
|
|
# with the scores of the two SBCharSetProbers to produce a final answer.
|
||
|
|
#
|
||
|
|
# The SBCSGroupProber is responsible for stripping the original text of HTML
|
||
|
|
# tags, English characters, numbers, low-ASCII punctuation characters, spaces
|
||
|
|
# and new lines. It reduces any sequence of such characters to a single space.
|
||
|
|
# The buffer fed to each prober in the SBCS group prober is pure text in
|
||
|
|
# high-ASCII.
|
||
|
|
# The two SBCharSetProbers (model probers) share the same language model:
|
||
|
|
# Win1255Model.
|
||
|
|
# The first SBCharSetProber uses the model normally as any other
|
||
|
|
# SBCharSetProber does, to recognize windows-1255, upon which this model was
|
||
|
|
# built. The second SBCharSetProber is told to make the pair-of-letter
|
||
|
|
# lookup in the language model backwards. This in practice exactly simulates
|
||
|
|
# a visual Hebrew model using the windows-1255 logical Hebrew model.
|
||
|
|
#
|
||
|
|
# The HebrewProber is not using any language model. All it does is look for
|
||
|
|
# final-letter evidence suggesting the text is either logical Hebrew or visual
|
||
|
|
# Hebrew. Disjointed from the model probers, the results of the HebrewProber
|
||
|
|
# alone are meaningless. HebrewProber always returns 0.00 as confidence
|
||
|
|
# since it never identifies a charset by itself. Instead, the pointer to the
|
||
|
|
# HebrewProber is passed to the model probers as a helper "Name Prober".
|
||
|
|
# When the Group prober receives a positive identification from any prober,
|
||
|
|
# it asks for the name of the charset identified. If the prober queried is a
|
||
|
|
# Hebrew model prober, the model prober forwards the call to the
|
||
|
|
# HebrewProber to make the final decision. In the HebrewProber, the
|
||
|
|
# decision is made according to the final-letters scores maintained and Both
|
||
|
|
# model probers scores. The answer is returned in the form of the name of the
|
||
|
|
# charset identified, either "windows-1255" or "ISO-8859-8".
|
||
|
|
|
||
|
|
class HebrewProber(CharSetProber):
|
||
|
|
# windows-1255 / ISO-8859-8 code points of interest
|
||
|
|
FINAL_KAF = 0xea
|
||
|
|
NORMAL_KAF = 0xeb
|
||
|
|
FINAL_MEM = 0xed
|
||
|
|
NORMAL_MEM = 0xee
|
||
|
|
FINAL_NUN = 0xef
|
||
|
|
NORMAL_NUN = 0xf0
|
||
|
|
FINAL_PE = 0xf3
|
||
|
|
NORMAL_PE = 0xf4
|
||
|
|
FINAL_TSADI = 0xf5
|
||
|
|
NORMAL_TSADI = 0xf6
|
||
|
|
|
||
|
|
# Minimum Visual vs Logical final letter score difference.
|
||
|
|
# If the difference is below this, don't rely solely on the final letter score
|
||
|
|
# distance.
|
||
|
|
MIN_FINAL_CHAR_DISTANCE = 5
|
||
|
|
|
||
|
|
# Minimum Visual vs Logical model score difference.
|
||
|
|
# If the difference is below this, don't rely at all on the model score
|
||
|
|
# distance.
|
||
|
|
MIN_MODEL_DISTANCE = 0.01
|
||
|
|
|
||
|
|
VISUAL_HEBREW_NAME = "ISO-8859-8"
|
||
|
|
LOGICAL_HEBREW_NAME = "windows-1255"
|
||
|
|
|
||
|
|
def __init__(self):
|
||
|
|
super(HebrewProber, self).__init__()
|
||
|
|
self._final_char_logical_score = None
|
||
|
|
self._final_char_visual_score = None
|
||
|
|
self._prev = None
|
||
|
|
self._before_prev = None
|
||
|
|
self._logical_prober = None
|
||
|
|
self._visual_prober = None
|
||
|
|
self.reset()
|
||
|
|
|
||
|
|
def reset(self):
|
||
|
|
self._final_char_logical_score = 0
|
||
|
|
self._final_char_visual_score = 0
|
||
|
|
# The two last characters seen in the previous buffer,
|
||
|
|
# mPrev and mBeforePrev are initialized to space in order to simulate
|
||
|
|
# a word delimiter at the beginning of the data
|
||
|
|
self._prev = ' '
|
||
|
|
self._before_prev = ' '
|
||
|
|
# These probers are owned by the group prober.
|
||
|
|
|
||
|
|
def set_model_probers(self, logicalProber, visualProber):
|
||
|
|
self._logical_prober = logicalProber
|
||
|
|
self._visual_prober = visualProber
|
||
|
|
|
||
|
|
def is_final(self, c):
|
||
|
|
return c in [self.FINAL_KAF, self.FINAL_MEM, self.FINAL_NUN,
|
||
|
|
self.FINAL_PE, self.FINAL_TSADI]
|
||
|
|
|
||
|
|
def is_non_final(self, c):
|
||
|
|
# The normal Tsadi is not a good Non-Final letter due to words like
|
||
|
|
# 'lechotet' (to chat) containing an apostrophe after the tsadi. This
|
||
|
|
# apostrophe is converted to a space in FilterWithoutEnglishLetters
|
||
|
|
# causing the Non-Final tsadi to appear at an end of a word even
|
||
|
|
# though this is not the case in the original text.
|
||
|
|
# The letters Pe and Kaf rarely display a related behavior of not being
|
||
|
|
# a good Non-Final letter. Words like 'Pop', 'Winamp' and 'Mubarak'
|
||
|
|
# for example legally end with a Non-Final Pe or Kaf. However, the
|
||
|
|
# benefit of these letters as Non-Final letters outweighs the damage
|
||
|
|
# since these words are quite rare.
|
||
|
|
return c in [self.NORMAL_KAF, self.NORMAL_MEM,
|
||
|
|
self.NORMAL_NUN, self.NORMAL_PE]
|
||
|
|
|
||
|
|
def feed(self, byte_str):
|
||
|
|
# Final letter analysis for logical-visual decision.
|
||
|
|
# Look for evidence that the received buffer is either logical Hebrew
|
||
|
|
# or visual Hebrew.
|
||
|
|
# The following cases are checked:
|
||
|
|
# 1) A word longer than 1 letter, ending with a final letter. This is
|
||
|
|
# an indication that the text is laid out "naturally" since the
|
||
|
|
# final letter really appears at the end. +1 for logical score.
|
||
|
|
# 2) A word longer than 1 letter, ending with a Non-Final letter. In
|
||
|
|
# normal Hebrew, words ending with Kaf, Mem, Nun, Pe or Tsadi,
|
||
|
|
# should not end with the Non-Final form of that letter. Exceptions
|
||
|
|
# to this rule are mentioned above in isNonFinal(). This is an
|
||
|
|
# indication that the text is laid out backwards. +1 for visual
|
||
|
|
# score
|
||
|
|
# 3) A word longer than 1 letter, starting with a final letter. Final
|
||
|
|
# letters should not appear at the beginning of a word. This is an
|
||
|
|
# indication that the text is laid out backwards. +1 for visual
|
||
|
|
# score.
|
||
|
|
#
|
||
|
|
# The visual score and logical score are accumulated throughout the
|
||
|
|
# text and are finally checked against each other in GetCharSetName().
|
||
|
|
# No checking for final letters in the middle of words is done since
|
||
|
|
# that case is not an indication for either Logical or Visual text.
|
||
|
|
#
|
||
|
|
# We automatically filter out all 7-bit characters (replace them with
|
||
|
|
# spaces) so the word boundary detection works properly. [MAP]
|
||
|
|
|
||
|
|
if self.state == ProbingState.NOT_ME:
|
||
|
|
# Both model probers say it's not them. No reason to continue.
|
||
|
|
return ProbingState.NOT_ME
|
||
|
|
|
||
|
|
byte_str = self.filter_high_byte_only(byte_str)
|
||
|
|
|
||
|
|
for cur in byte_str:
|
||
|
|
if cur == ' ':
|
||
|
|
# We stand on a space - a word just ended
|
||
|
|
if self._before_prev != ' ':
|
||
|
|
# next-to-last char was not a space so self._prev is not a
|
||
|
|
# 1 letter word
|
||
|
|
if self.is_final(self._prev):
|
||
|
|
# case (1) [-2:not space][-1:final letter][cur:space]
|
||
|
|
self._final_char_logical_score += 1
|
||
|
|
elif self.is_non_final(self._prev):
|
||
|
|
# case (2) [-2:not space][-1:Non-Final letter][
|
||
|
|
# cur:space]
|
||
|
|
self._final_char_visual_score += 1
|
||
|
|
else:
|
||
|
|
# Not standing on a space
|
||
|
|
if ((self._before_prev == ' ') and
|
||
|
|
(self.is_final(self._prev)) and (cur != ' ')):
|
||
|
|
# case (3) [-2:space][-1:final letter][cur:not space]
|
||
|
|
self._final_char_visual_score += 1
|
||
|
|
self._before_prev = self._prev
|
||
|
|
self._prev = cur
|
||
|
|
|
||
|
|
# Forever detecting, till the end or until both model probers return
|
||
|
|
# ProbingState.NOT_ME (handled above)
|
||
|
|
return ProbingState.DETECTING
|
||
|
|
|
||
|
|
@property
|
||
|
|
def charset_name(self):
|
||
|
|
# Make the decision: is it Logical or Visual?
|
||
|
|
# If the final letter score distance is dominant enough, rely on it.
|
||
|
|
finalsub = self._final_char_logical_score - self._final_char_visual_score
|
||
|
|
if finalsub >= self.MIN_FINAL_CHAR_DISTANCE:
|
||
|
|
return self.LOGICAL_HEBREW_NAME
|
||
|
|
if finalsub <= -self.MIN_FINAL_CHAR_DISTANCE:
|
||
|
|
return self.VISUAL_HEBREW_NAME
|
||
|
|
|
||
|
|
# It's not dominant enough, try to rely on the model scores instead.
|
||
|
|
modelsub = (self._logical_prober.get_confidence()
|
||
|
|
- self._visual_prober.get_confidence())
|
||
|
|
if modelsub > self.MIN_MODEL_DISTANCE:
|
||
|
|
return self.LOGICAL_HEBREW_NAME
|
||
|
|
if modelsub < -self.MIN_MODEL_DISTANCE:
|
||
|
|
return self.VISUAL_HEBREW_NAME
|
||
|
|
|
||
|
|
# Still no good, back to final letter distance, maybe it'll save the
|
||
|
|
# day.
|
||
|
|
if finalsub < 0.0:
|
||
|
|
return self.VISUAL_HEBREW_NAME
|
||
|
|
|
||
|
|
# (finalsub > 0 - Logical) or (don't know what to do) default to
|
||
|
|
# Logical.
|
||
|
|
return self.LOGICAL_HEBREW_NAME
|
||
|
|
|
||
|
|
@property
|
||
|
|
def language(self):
|
||
|
|
return 'Hebrew'
|
||
|
|
|
||
|
|
@property
|
||
|
|
def state(self):
|
||
|
|
# Remain active as long as any of the model probers are active.
|
||
|
|
if (self._logical_prober.state == ProbingState.NOT_ME) and \
|
||
|
|
(self._visual_prober.state == ProbingState.NOT_ME):
|
||
|
|
return ProbingState.NOT_ME
|
||
|
|
return ProbingState.DETECTING
|