Module: CommentStrip::LanguageFamilies::C

Defined in:
lib/comment_strip/language_families/c.rb

Class Method Summary collapse

Class Method Details

.strip(input, lf, **options) ⇒ Object 



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# File 'lib/comment_strip/language_families/c.rb', line 50

def self.strip input, lf, **options

  return input if input.nil?
  return input if input.empty?

  line    =   0
  column  =   0

  # States:
  #
  # - :c_comment          - in a C comment, i.e. from immediately after "/*"
  # - :c_comment_star     - in a C comment when just received '*', e.g. from immediately after "/* comment *"
  # - :cpp_comment        - in a C++ comment, i.e. from immediately after "//"
  # - :dq_string          - within a double-quoted string
  # - :dq_string_escape   - within a double-quoted string when just received a '"', e.g. from immediately after '"the next word is quoted \'
  # - :slash_start        - having found a slash (not in a string)
  # - :sq_string_closing  - waiting for final '\'' in a single-quoted string
  # - :sq_string_escape   - within a escaped single-quoted string, i.e. from immediately after "'\"
  # - :sq_string_open     - within a single-quoted string, i.e. from immediately after "'"
  # - :text               - regular part of the code

  state   =   :text

  r       =   ''

  cc_lines =   0

  input.each_char do |c|

    case c
    when ?\r, ?\n

      line += 1
      column = 0
    else

      column += 1
    end

    skip = false

    case c
    when ?\r, ?\n

      case state
      when :c_comment, :c_comment_star

        cc_lines += 1

        state = :c_comment
      when :cpp_comment

        state = :text
      when :sq_string_escape, :sq_string_closing

        state = :text
      when :dq_string_escape

        state = :dq_string
      when :slash_start

        r << '/'

        state = :text
      end
    else

      # special cases:
      #
      # - for escaped single/double quote
      # - for slash-start
      # - for comment-star

      case state
      when :sq_string_open

        state = (?\\ == c) ? :sq_string_escape : :sq_string_closing
      when :sq_string_escape

        state = :sq_string_closing
      when :dq_string_escape

        state = :dq_string
      when :c_comment_star

        case c
        when ?/

          r << ?\n * cc_lines
          cc_lines = 0

          state = :text
          skip = true
        when '*'

          ;
        else

          state = :c_comment
        end
      else

        if false
        elsif state == :slash_start && ('/' != c && '*' != c)

          state = :text
          r << '/'
        else

          case c
          when '/'

            case state
            when :text

              state = :slash_start
            when :slash_start

              state = :cpp_comment
            when :c_comment_star

              r << ?\n * cc_lines
              cc_lines = 0

              state = :text
              skip = true
            else

              ;
            end
          when '*'

            case state
            when :slash_start

              state = :c_comment
            when :c_comment

              state = :c_comment_star
            else

              ;
            end
          when ?\'

            case state
            when :text

              state = :sq_string_open
            when :sq_string_closing

              state = :text
            else

              ;
            end
          when '"'

            case state
            when :text

              state = :dq_string
            when :dq_string

              state = :text
            else

              ;
            end
          when ?\\

            case state
            when :sq_string_open

              state = :sq_string_escape
            when :sq_string_escape

              state = :sq_string_closing
            when :dq_string

              state = :dq_string_escape
            else

              ;
            end
          else

            case state
            when :sq_string_escape

              state = :sq_string_closing
            else

              ;
            end
          end
        end
      end
    end


    case state
    when :slash_start
    when :cpp_comment
    when :c_comment
    when :c_comment_star

      ;
    else

      r << c unless skip
    end
  end

  r
end