# module RDoc::Encoding

This class is a wrapper around File IO and Encoding that helps RDoc load files and convert them to the correct encoding.

### Public Class Methods

read_file(filename, encoding, force_transcode = false) click to toggle source

Reads the contents of `filename` and handles any encoding directives in the file.

The content will be converted to the `encoding`. If the file cannot be converted a warning will be printed and nil will be returned.

If `force_transcode` is true the document will be transcoded and any unknown character in the target encoding will be replaced with '?'

    # File lib/rdoc/encoding.rb, line 19
    def self.read_file filename, encoding, force_transcode = false
      content = open filename, "rb" do |f| f.read end
      content.gsub!("\r\n", "\n") if RUBY_PLATFORM =~ /mswin|mingw/

      utf8 = content.sub!(/\A\xef\xbb\xbf/, '')

      RDoc::Encoding.set_encoding content

      begin
        encoding ||= Encoding.default_external
        orig_encoding = content.encoding

        if not orig_encoding.ascii_compatible? then
          content.encode! encoding
        elsif utf8 then
          content.force_encoding Encoding::UTF_8
          content.encode! encoding
        else
          # assume the content is in our output encoding
          content.force_encoding encoding
        end

        unless content.valid_encoding? then
          # revert and try to transcode
          content.force_encoding orig_encoding
          content.encode! encoding
        end

        unless content.valid_encoding? then
          warn "unable to convert #{filename} to #{encoding}, skipping"
          content = nil
        end
      rescue Encoding::InvalidByteSequenceError,
             Encoding::UndefinedConversionError => e
        if force_transcode then
          content.force_encoding orig_encoding
          content.encode!(encoding,
                          :invalid => :replace, :undef => :replace,
                          :replace => '?')
          return content
        else
          warn "unable to convert #{e.message} for #{filename}, skipping"
          return nil
        end
      end

      content
    rescue ArgumentError => e
      raise unless e.message =~ /unknown encoding name - (.*)/
      warn "unknown encoding name \"#{$1}\" for #{filename}, skipping"
      nil
    rescue Errno::EISDIR, Errno::ENOENT
      nil
    end

remove_frozen_string_literal(string) click to toggle source

    # File lib/rdoc/encoding.rb, line 74
    def self.remove_frozen_string_literal string
      string =~ /\A(?:#!.*\n)?(.*\n)/
      first_line = $1

      if first_line =~ /\A# +frozen[-_]string[-_]literal[=:].+$/i
        string.sub! first_line, ''
      end
    end

set_encoding(string) click to toggle source

Sets the encoding of `string` based on the magic comment

    # File lib/rdoc/encoding.rb, line 86
    def self.set_encoding string
      remove_frozen_string_literal string

      string =~ /\A(?:#!.*\n)?(.*\n)/

      first_line = $1

      name = case first_line
             when /^<\?xml[^?]*encoding=(["'])(.*?)\1/ then $2
             when /\b(?:en)?coding[=:]\s*([^\s;]+)/i   then $1
             else                                           return
             end

      string.sub! first_line, ''

      remove_frozen_string_literal string

      enc = Encoding.find name
      string.force_encoding enc if enc
    end