Class: JJDecoder

Inherits:
Object
  • Object
show all
Defined in:
lib/jjdecoder.rb,
lib/jjdecoder/version.rb

Constant Summary collapse

VERSION = 
'0.1.0'

Instance Method Summary collapse

Constructor Details

#initialize(jj_encoded_data) ⇒ JJDecoder 



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# File 'lib/jjdecoder.rb', line 4

def initialize(jj_encoded_data)
  @encoded_str = jj_encoded_data
end

Instance Method Details

#decode ⇒ Object 



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# File 'lib/jjdecoder.rb', line 8

def decode
  clean
  startpos, endpos, gv = check_palindrome

  if startpos == endpos
    raise 'No data!'
  end

  data = @encoded_str[startpos...endpos]

  # ex decode string
  b = ['___+', '__$+', '_$_+', '_$$+', '$__+', '$_$+', '$$_+', '$$$+', '$___+', '$__$+', '$_$_+', '$_$$+', '$$__+', '$$_$+', '$$$_+', '$$$$+']

  # lotu
  str_l = '(![]+"")[' + gv + '._$_]+'
  str_o   = gv + '._$+'
  str_t = gv + '.__+'
  str_u = gv + '._+'

  # 0123456789abcdef
  str_hex = gv + '.'

  # s
  str_s = '"'
  gvsig = gv + '.'

  str_quote = '\\\\\\"'
  str_slash = '\\\\\\\\'

  str_lower = '\\\\"+'
  str_upper = '\\\\"+' + gv + '._+'

  str_end  = '"+' # end of s loop

  out = ''
  while data != ''

    # l o t u
    if data.index(str_l) == 0
      data = data[str_l.size..-1]
      out += 'l'
      next
    elsif data.index(str_o) == 0
      data = data[str_o.size..-1]
      out += 'o'
      next
    elsif data.index(str_t) == 0
      data = data[str_t.size..-1]
      out += 't'
      next
    elsif data.index(str_u) == 0
      data = data[str_u.size..-1]
      out += 'u'
      next
    end

    # 0123456789abcdef
    if data.index(str_hex) == 0
      data = data[str_hex.size..-1]

      # check every element of hex decode string for a match
      b.size.times do |i|
        if data.index(b[i]) == 0
          data = data[b[i].size..-1]
          out += i.to_s(16)
          break
        end
      end

      next
    end

    # start of s block
    if data.index(str_s) == 0
      data = data[str_s.size..-1]

      # check if "R
      if data.index(str_upper) == 0 # r4 n >= 128
        data = data[str_upper.size..-1] # skip sig

        ch_str = ''
        2.times do |i| # shouldn't be more than 2 hex chars
          # gv + "."+b[ c ]
          if data.index(gvsig) == 0
            data = data[gvsig.size..-1] # skip gvsig

            b.size.times do |k| # for every entry in b
              if data.index(b[k]) == 0
                data = data[b[k].size..-1]
                ch_str = k.to_s(16)
                break
              end
            end
          else
            break # done
          end
        end

        out += ch_str.to_i(16).chr
        next
      elsif data.index(str_lower) == 0 # r3 check if "R // n < 128
        data = data[str_lower.size..-1] # skip sig

        ch_str = ''
        ch_lotux = ''
        temp = ''
        b_check_r1 = 0
        3.times do |j| # shouldn't be more than 3 octal chars
          if j > 1 # lotu check
            if data.index(str_l) == 0
              data = data[str_l.size..-1]
              ch_lotux = 'l'
              break
            elsif data.index(str_o) == 0
              data = data[str_o.size..-1]
              ch_lotux = 'o'
              break
            elsif data.index(str_t) == 0
              data = data[str_t.size..-1]
              ch_lotux = 't'
              break
            elsif data.index(str_u) == 0
              data = data[str_u.size..-1]
              ch_lotux = 'u'
              break
            end
          end

          # gv + "."+b[ c ]
          if data.index(gvsig) == 0
            temp = data[gvsig.size..-1]
            8.times do |k| # for every entry in b octal
              if temp.index(b[k]) == 0
                if (ch_str + k.to_s).to_i(8) > 128
                  b_check_r1 = 1
                  break
                end

                ch_str += k.to_s
                data = data[gvsig.size..-1] # skip gvsig
                data = data[b[k].size..-1]
                break
              end
            end

            if b_check_r1 == 1
              if data.index(str_hex) == 0 # 0123456789abcdef
                data = data[str_hex.size..-1]

                # check every element of hex decode string for a match
                b.size.times do |i|
                  if data.index(b[i]) == 0
                    data = data[b[i].size..-1]
                    ch_lotux = i.to_s(16)
                    break
                  end
                end

                break
              end
            end
          else
            break # done
          end
        end

        out += ch_str.to_i(8).chr + ch_lotux
        next # step out of the while loop
      else # "S ----> "SR or "S+
        # if there is, loop s until R 0r +
        # if there is no matching s block, throw error

        match = 0
        n = nil

        # searching for matching pure s block
        while true
          n = data[0].ord
          if data.index(str_quote) == 0
            data = data[str_quote.size..-1]
            out += '"'
            match += 1
            next
          elsif data.index(str_slash) == 0
            data = data[str_slash.size..-1]
            out += '\\'
            match += 1
            next
          elsif data.index(str_end) == 0 # reached end off S block ? +
            if match == 0
              raise '+ no match S block: ' + data
            end
            data = data[str_end.size..-1]
            break # step out of the while loop
          elsif data.index(str_upper) == 0 # r4 reached end off S block ? - check if "R n >= 128
            if match == 0
              raise 'no match S block n>128: ' + data
            end

            data = data[str_upper.size..-1] # skip sig

            ch_str = ''
            ch_lotux = ''

            10.times do |j| # shouldn't be more than 10 hex chars
              if j > 1 # lotu check
                if data.index(str_l) == 0
                  data = data[str_l.size..-1]
                  ch_lotux = 'l'
                  break
                elsif data.index(str_o) == 0
                  data = data[str_o.size..-1]
                  ch_lotux = 'o'
                  break
                elsif data.index(str_t) == 0
                  data = data[str_t.size..-1]
                  ch_lotux = 't'
                  break
                elsif data.index(str_u) == 0
                  data = data[str_u.size..-1]
                  ch_lotux = 'u'
                  break
                end
              end

              # gv + "."+b[ c ]
              if data.index(gvsig) == 0
                data = data[gvsig.size..-1] # skip gvsig
                b.size.times do |k| # for every entry in b
                  if data.index(b[k]) == 0
                    data = data[b[k].size..-1]
                    ch_str += k.to_s(16)
                    break
                  end
                end
              else
                break # done
              end
            end

            out += ch_str.to_i(16).chr
            break # step out of the while loop
          elsif data.index(str_lower) == 0 # r3 check if "R // n < 128
            if match == 0
              raise 'no match S block n<128: ' + data
            end

            data = data[str_lower.size..-1] # skip sig

            ch_str = ''
            ch_lotux = ''
            temp = ''
            b_check_r1 = 0

            3.times do |j| # shouldn't be more than 3 octal chars
              if j > 1 # lotu check
                if data.index(str_l) == 0
                  data = data[str_l.size..-1]
                  ch_lotux = 'l'
                  break
                elsif data.index(str_o) == 0
                  data = data[str_o.size..-1]
                  ch_lotux = 'o'
                  break
                elsif data.index(str_t) == 0
                  data = data[str_t.size..-1]
                  ch_lotux = 't'
                  break
                elsif data.index(str_u) == 0
                  data = data[str_u.size..-1]
                  ch_lotux = 'u'
                  break
                end
              end

              # gv + "."+b[ c ]
              if data.index(gvsig) == 0
                temp = data[gvsig.size..-1]
                8.times do |k| # for every entry in b octal
                  if temp.index(b[k]) == 0
                    if (ch_str + k.to_s).to_i(8) > 128
                      b_check_r1 = 1
                      break
                    end

                    ch_str += k.to_s
                    data = data[gvsig.size..-1] # skip gvsig
                    data = data[b[k].size..-1]
                    break
                  end
                end

                if b_check_r1 == 1
                  if data.index(str_hex) == 0 # 0123456789abcdef
                    data = data[str_hex.size..-1]
                    # check every element of hex decode string for a match
                    b.size.times do |i|
                      if data.index(b[i]) == 0
                        data = data[b[i].size..-1]
                        ch_lotux = i.to_s(16)
                        break
                      end
                    end
                  end
                end
              else
                break # done
              end
            end

            out += ch_str.to_i(8).chr + ch_lotux
            break # step out of the while loop
          elsif (0x21 <= n and n <= 0x2f) or (0x3A <= n and n <= 0x40) or ( 0x5b <= n and n <= 0x60 ) or ( 0x7b <= n and n <= 0x7f )
            out += data[0]
            data = data[1..-1]
            match += 1
          end
        end
        next
      end
    end
    print 'No match : ' + data
    break
  end

  return out
end