gistfile1.rb

module LineNumber
  class Tag < Struct.new(:name, :close, :line, :in_script)
  end

  class LineNumber
    attr_reader :tags
    def self.parse(str)
      parser = self.new(str)
      return parser.parse
    end

    def initialize(str)
      @str = str
      @tags = []
    end

    def parse
      @pos = 0
      @len = @str.length

      tokens = {
        '<' => 0,
        '/' => 1,
        '>' => 2
      }

      flags = {
        #     0  1  2  3  4
        0 => [1, 0, 0, 0, 0], # 
        1 => [0, 2, 0, 3, 0], # <
        2 => [0, 0, 0, 4, 0], # </
        3 => [0, 0, 5, 3, 5], # <t
        4 => [0, 0, 6, 4, 0], # </t
        5 => [1, 0, 0, 0, 0], # <tag...
        6 => [1, 0, 0, 0, 0]  # </tag>
      }
      @log = ""
      @buf = ""
      current = 0
      line = 1

      in_script = false

      while @pos < @len
        ch = @str[@pos].chr
        line += 1 if ch == "\n"

        token = ch =~ /[a-z0-9]/i ? 3 : (tokens[ch] || 4)
        flag = flags[current][token]

        case flag
        when 0
        when 1
          @buf = ""
        when 2
          @buf = ""
        when 3
          @buf += ch
        when 4
          @buf += ch
        when 5
          @tags << Tag.new(@buf, false, line, in_script)
          in_script = true if @buf == 'script'
          @buf = ""
        when 6
          @tags << Tag.new(@buf, true, line, in_script)
          in_script = false if @buf == 'script'
          @buf = ""
        end

        current = flag
        @pos += 1
      end

      return @tags
    end
  end
end