Class: CharDet::SingleByteCharSetProber

Inherits:
CharSetProber show all
Defined in:
lib/rchardet/sbcharsetprober.rb

Overview

NEGATIVE_CAT = 0

Instance Attribute Summary

Attributes inherited from CharSetProber

#active

Instance Method Summary collapse

Methods inherited from CharSetProber

#filter_high_bit_only, #filter_with_english_letters, #filter_without_english_letters, #result, #state

Constructor Details

#initialize(model, reversed = false, nameProber = nil) ⇒ SingleByteCharSetProber

Returns a new instance of SingleByteCharSetProber.



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# File 'lib/rchardet/sbcharsetprober.rb', line 41

def initialize(model, reversed=false, nameProber=nil)
  super()
  @_mModel = model
  @_mReversed = reversed # TRUE if we need to reverse every pair in the model lookup
  @_mNameProber = nameProber # Optional auxiliary prober for name decision
  reset()
end

Instance Method Details

#charset_name ⇒ Object 



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# File 'lib/rchardet/sbcharsetprober.rb', line 58

def charset_name
  if @_mNameProber
    return @_mNameProber.charset_name()
  else
    return @_mModel['charsetName']
  end
end

#confidence ⇒ Object 



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# File 'lib/rchardet/sbcharsetprober.rb', line 110

def confidence
  r = 0.01
  if @_mTotalSeqs > 0
    #            print self._mSeqCounters[POSITIVE_CAT], self._mTotalSeqs, self._mModel['mTypicalPositiveRatio']
    r = (1.0 * @_mSeqCounters[POSITIVE_CAT]) / @_mTotalSeqs / @_mModel['mTypicalPositiveRatio']
    #            print r, self._mFreqChar, self._mTotalChar
    r = r * @_mFreqChar / @_mTotalChar
    if r >= 1.0
      r = 0.99
    end
  end
  return r
end

#feed(aBuf) ⇒ Object 



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# File 'lib/rchardet/sbcharsetprober.rb', line 66

def feed(aBuf)
  if not @_mModel['keepEnglishLetter']
    aBuf = filter_without_english_letters(aBuf)
  end
  aLen = aBuf.length
  if not aLen
    return state()
  end
  aBuf.each_byte do |b|
    c = b.chr
    order = @_mModel['charToOrderMap'][c[0].ord]
    if order < SYMBOL_CAT_ORDER
      @_mTotalChar += 1
    end
    if order < SAMPLE_SIZE
      @_mFreqChar += 1
      if @_mLastOrder < SAMPLE_SIZE
        @_mTotalSeqs += 1
        if not @_mReversed
          @_mSeqCounters[@_mModel['precedenceMatrix'][(@_mLastOrder * SAMPLE_SIZE) + order]] += 1
        else # reverse the order of the letters in the lookup
          @_mSeqCounters[@_mModel['precedenceMatrix'][(order * SAMPLE_SIZE) + @_mLastOrder]] += 1
        end
      end
    end
    @_mLastOrder = order
  end

  if state() == EDetecting
    if @_mTotalSeqs > SB_ENOUGH_REL_THRESHOLD
      cf = confidence()
      if cf > POSITIVE_SHORTCUT_THRESHOLD
        $stderr << "#{@_mModel['charsetName']} confidence = #{cf}, we have a winner\n" if $debug
        @_mState = EFoundIt
      elsif cf < NEGATIVE_SHORTCUT_THRESHOLD
        $stderr << "#{@_mModel['charsetName']} confidence = #{cf}, below negative shortcut threshold #{NEGATIVE_SHORTCUT_THRESHOLD}\n" if $debug
        @_mState = ENotMe
      end
    end
  end

  return state()
end

#reset ⇒ Object 



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# File 'lib/rchardet/sbcharsetprober.rb', line 49

def reset
  super()
  @_mLastOrder = 255 # char order of last character
  @_mSeqCounters = [0] * NUMBER_OF_SEQ_CAT
  @_mTotalSeqs = 0
  @_mTotalChar = 0
  @_mFreqChar = 0 # characters that fall in our sampling range
end