prepare_strip

# File lib/csv/parser.rb, line 411
    def prepare_strip
      @strip = @options[:strip]
      @escaped_strip = nil
      @strip_value = nil
      if @strip.is_a?(String)
        case @strip.length
        when 0
          raise ArgumentError, ":strip must not be an empty String"
        when 1
          # ok
        else
          raise ArgumentError, ":strip doesn't support 2 or more characters yet"
        end
        @strip = @strip.encode(@encoding)
        @escaped_strip = Regexp.escape(@strip)
        if @quote_character
          @strip_value = Regexp.new(@escaped_strip +
                                    "+".encode(@encoding))
        end
        @need_robust_parsing = true
      elsif @strip
        strip_values = " \t\r\n\f\v"
        @escaped_strip = strip_values.encode(@encoding)
        if @quote_character
          @strip_value = Regexp.new("[#{strip_values}]+".encode(@encoding))
        end
        @need_robust_parsing = true
      end
    end