decoder.rb

require 'awesome_print'
require 'csv'
load 'trie.rb'

@charToPattern = {
  "a"=>/^1(\d*)/,
 "b"=>/^10(\d*)/,
 "c"=>/^11(\d*)/,
 "d"=>/^100(\d*)/,
 "e"=>/^101(\d*)/,
 "f"=>/^110(\d*)/,
 "g"=>/^111(\d*)/,
 "h"=>/^1000(\d*)/,
 "i"=>/^1001(\d*)/,
 "j"=>/^1010(\d*)/,
 "k"=>/^1011(\d*)/,
 "l"=>/^1100(\d*)/,
 "m"=>/^1101(\d*)/,
 "n"=>/^1110(\d*)/,
 "o"=>/^1111(\d*)/,
 "p"=>/^10000(\d*)/,
 "q"=>/^10001(\d*)/,
 "r"=>/^10010(\d*)/,
 "s"=>/^10011(\d*)/,
 "t"=>/^10100(\d*)/,
 "u"=>/^10101(\d*)/,
 "v"=>/^10110(\d*)/,
 "w"=>/^10111(\d*)/,
 "x"=>/^11000(\d*)/,
 "y"=>/^11001(\d*)/,
 "z"=>/^11010(\d*)/}

@patternToChar = @charToPattern.inject({}) do |hsh, (k,v)|
  hsh[v] = k
  hsh
end

@patterns = @charToPattern.values
@code = "10001010110001000101100001001101111000011010110".split("")

@trie = Trie.new

def traverse(code, trie)
  if !code.empty?
    for char in @charToPattern.keys
      pattern = @charToPattern[char]
      if(match_obj = code.join('').match(pattern))
        puts "Matching char "+char+" with residual "+match_obj[1]+" from "+code.join('')
        trie = trie.extend(char, traverse(match_obj[1].split(""), Trie.new))
      else
        next
      end
    end

    return trie
  else
    # Mark true string conclusion
    trie.meta = true
    return trie
    # TODO
  end
end

# Ref against dictionary
words = []
File.open("/usr/share/dict/words") do |file|
  file.each do |line|
    words << line.strip
  end
end

words = words.map(&:downcase).uniq.map do |w|
  w.length > 3 ? Regexp.new(w) : nil
end.compact


@trie = traverse(@code, @trie)
CSV.open("results.csv", "wb") do |csv|

  csv << ["Decoded word", "Matching dictionary words"]

  @trie.valid_paths.each do |w|
    line = []
    line << w

    puts "Cross-referencing "+w

    matches = words.map do |dictionary_word|
      w.match(dictionary_word)
    end.compact.map do |m|
      m[0]
    end

    if !matches.empty?
      line << matches.join(' ')
      puts matches.join(' ')
    end

    csv << line.flatten
  end
end