Class: Analyzers::Utils::SpellChecker

Inherits:
Object
  • Object
show all
Defined in:
lib/crypto-toolbox/analyzers/utils/spell_checker.rb

Instance Method Summary collapse

Constructor Details

#initialize(dict_lang = "en_US") ⇒ SpellChecker

Returns a new instance of SpellChecker.



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# File 'lib/crypto-toolbox/analyzers/utils/spell_checker.rb', line 8

def initialize(dict_lang="en_US")
  @dict = FFI::Hunspell.dict(dict_lang)
  # @dict2 = FFI::Aspell::Speller.new(dict_lang)
end

Instance Method Details

#human_language?(str) ⇒ Boolean

Check whether a given string seems to be part of a human language using the given dictionary

NOTE: Using shell instead of hunspell ffi causes lots of escaping errors, even with shellwords.escape errors = Float(‘echo ’#Shellwords.escape(str)‘ |hunspell -l |wc -l `.split.first)

Returns:

  • (Boolean) 


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# File 'lib/crypto-toolbox/analyzers/utils/spell_checker.rb', line 51

def human_language?(str)
  #NOTE should be reject 1char numbers or all 1 char symbols
  words       = str.split(" ").reject{|w| (w.length < 2 || w =~ /^[0-9]+$/) }
  word_amount = words.length
  errors      = words.map{|e| check?(e) }.count{|e| e == false}
  
  error_rate = errors.to_f/word_amount

  report_error_rate(str,error_rate) if ENV["DEBUG_ANALYSIS"]

  error_rate_sufficient?(error_rate)
end

#human_phrase?(string) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/crypto-toolbox/analyzers/utils/spell_checker.rb', line 38

def human_phrase?(string)
  string.split(" ").all?{|part| human_word?(part)}
end

#human_word?(str) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/crypto-toolbox/analyzers/utils/spell_checker.rb', line 34

def human_word?(str)
  check?(str)
end

#known_words(str) ⇒ Object

NOTE: About spelling error rates and language detection:

missing punctuation support may lead to > 2% errors on valid texts, thus we use a high value . invalid decryptions tend to have spell error rates > 70 Some statistics about it: > summary(invalids)

  Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
0.6000  1.0000  1.0000  0.9878  1.0000  1.0000

> summary(cut(invalids,10))

(0.6,0.64] (0.64,0.68] (0.68,0.72] (0.72,0.76]  (0.76,0.8]  (0.8,0.84] 
         8          13           9         534        1319        2809

(0.84,0.88] (0.88,0.92] (0.92,0.96] (0.96,1]

10581       46598      198477     1440651

NOTE: There is ony caveat: Short messages with < 5 words may have 33 or 50% error rates if numbers or single char words are taken into account



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# File 'lib/crypto-toolbox/analyzers/utils/spell_checker.rb', line 30

def known_words(str)
  words = str.split(" ").select{|w| check?(w) }
end

#suggest(str) ⇒ Object 



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# File 'lib/crypto-toolbox/analyzers/utils/spell_checker.rb', line 42

def suggest(str)
  @dict.suggest(str)
end