# File lib/amazon.rb, line 65
    def initialize(config_str=nil)

      if config_str

        # We have been passed a config file as a string.
        #
        config_files = [ config_str ]
        config_class = StringIO

      else

        # Perform the usual search for the system and user config files.
        #
        config_files = [ File.join( '', 'etc', 'amazonrc' ) ]

        # Figure out where home is. The locations after HOME are for Windows.
        # [ruby-core:12347]
        #
        home = ENV['AMAZONRCDIR'] ||
               ENV['HOME'] || ENV['HOMEDRIVE'] + ENV['HOMEPATH'] ||
               ENV['USERPROFILE']
        user_rcfile = ENV['AMAZONRCFILE'] || '.amazonrc'

        if home
          config_files << File.expand_path( File.join( home, user_rcfile ) )
        end

        config_class = File
      end

      config_files.each do |cf|

        if config_class == StringIO
          readable = true
        else
          # We must determine whether the file is readable.
          #
          readable = File.exists?( cf ) && File.readable?( cf )
        end

        if readable

          Amazon.dprintf( 'Opening %s ...', cf ) if config_class == File
    
          config_class.open( cf ) { |f| lines = f.readlines }.each do |line|
            line.chomp!
    
            # Skip comments and blank lines.
            #
            next if line =~ /^(#|$)/
    
            Amazon.dprintf( 'Read: %s', line )
    
            # Store these, because we'll probably find a use for these later.
            #
            begin
              match = line.match( /^\s*(\S+)\s*=\s*(['"]?)([^'"]+)(['"]?)/ )
              key, begin_quote, val, end_quote = match[1, 4]
              raise ConfigError if begin_quote != end_quote

            rescue NoMethodError, ConfigError
              raise ConfigError, "bad config line: #{line}"
            end
    
            self[key] = val
    
          end
        end

      end

    end