125 lines
4.1 KiB
Ruby
Executable File
125 lines
4.1 KiB
Ruby
Executable File
######################## BEGIN LICENSE BLOCK ########################
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# The Original Code is Mozilla Universal charset detector code.
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#
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# The Initial Developer of the Original Code is
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# Netscape Communications Corporation.
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# Portions created by the Initial Developer are Copyright (C) 2001
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# the Initial Developer. All Rights Reserved.
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#
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# Contributor(s):
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# Jeff Hodges - port to Ruby
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# Mark Pilgrim - port to Python
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# Shy Shalom - original C code
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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# 02110-1301 USA
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######################### END LICENSE BLOCK #########################
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module CharDet
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SAMPLE_SIZE = 64
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SB_ENOUGH_REL_THRESHOLD = 1024
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POSITIVE_SHORTCUT_THRESHOLD = 0.95
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NEGATIVE_SHORTCUT_THRESHOLD = 0.05
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SYMBOL_CAT_ORDER = 250
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NUMBER_OF_SEQ_CAT = 4
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POSITIVE_CAT = NUMBER_OF_SEQ_CAT - 1
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#NEGATIVE_CAT = 0
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class SingleByteCharSetProber < CharSetProber
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def initialize(model, reversed=false, nameProber=nil)
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super()
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@_mModel = model
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@_mReversed = reversed # TRUE if we need to reverse every pair in the model lookup
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@_mNameProber = nameProber # Optional auxiliary prober for name decision
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reset()
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end
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def reset
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super()
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@_mLastOrder = 255 # char order of last character
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@_mSeqCounters = [0] * NUMBER_OF_SEQ_CAT
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@_mTotalSeqs = 0
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@_mTotalChar = 0
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@_mFreqChar = 0 # characters that fall in our sampling range
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end
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def get_charset_name
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if @_mNameProber
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return @_mNameProber.get_charset_name()
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else
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return @_mModel['charsetName']
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end
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end
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def feed(aBuf)
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if not @_mModel['keepEnglishLetter']
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aBuf = filter_without_english_letters(aBuf)
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end
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aLen = aBuf.length
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if not aLen
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return get_state()
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end
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aBuf.each_byte do |b|
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c = b.chr
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order = @_mModel['charToOrderMap'][c[0]]
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if order < SYMBOL_CAT_ORDER
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@_mTotalChar += 1
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end
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if order < SAMPLE_SIZE
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@_mFreqChar += 1
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if @_mLastOrder < SAMPLE_SIZE
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@_mTotalSeqs += 1
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if not @_mReversed
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@_mSeqCounters[@_mModel['precedenceMatrix'][(@_mLastOrder * SAMPLE_SIZE) + order]] += 1
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else # reverse the order of the letters in the lookup
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@_mSeqCounters[@_mModel['precedenceMatrix'][(order * SAMPLE_SIZE) + @_mLastOrder]] += 1
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end
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end
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end
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@_mLastOrder = order
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end
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if get_state() == EDetecting
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if @_mTotalSeqs > SB_ENOUGH_REL_THRESHOLD
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cf = get_confidence()
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if cf > POSITIVE_SHORTCUT_THRESHOLD
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$stderr << "#{@_mModel['charsetName']} confidence = #{cf}, we have a winner\n" if $debug
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@_mState = EFoundIt
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elsif cf < NEGATIVE_SHORTCUT_THRESHOLD
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$stderr << "#{@_mModel['charsetName']} confidence = #{cf}, below negative shortcut threshold #{NEGATIVE_SHORTCUT_THRESHOLD}\n" if $debug
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@_mState = ENotMe
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end
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end
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end
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return get_state()
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end
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def get_confidence
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r = 0.01
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if @_mTotalSeqs > 0
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# print self._mSeqCounters[POSITIVE_CAT], self._mTotalSeqs, self._mModel['mTypicalPositiveRatio']
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r = (1.0 * @_mSeqCounters[POSITIVE_CAT]) / @_mTotalSeqs / @_mModel['mTypicalPositiveRatio']
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# print r, self._mFreqChar, self._mTotalChar
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r = r * @_mFreqChar / @_mTotalChar
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if r >= 1.0
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r = 0.99
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end
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end
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return r
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end
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end
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end
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