lib/ftpd/telnet.rb in ftpd-0.9.0 vs lib/ftpd/telnet.rb in ftpd-0.10.0

@@ -48,11 +48,11 @@
     # Create a new instance with a command that may contain Telnet
     # sequences.
     # @param command [String]
 
     def initialize(command)
-      telnet_state_machine command
+      parse_command command
     end
 
     private
 
     module Codes
@@ -64,54 +64,49 @@
       IP   = 244.chr    # 0xf4
       DM   = 242.chr    # 0xf2
     end
     include Codes
 
-    def telnet_state_machine (command)
+    def accept(scanner)
+      @plain << scanner[1]
+    end
+
+    def reply_dont(scanner)
+      @reply << IAC + DONT + scanner[1]
+    end
+
+    def reply_wont(scanner)
+      @reply << IAC + WONT + scanner[1]
+    end
+
+    def ignore(scanner)
+    end
+
+    # Telnet sequences to handle, and how to handle them
+
+    SEQUENCES = [
+      [/#{IAC}(#{IAC})/, :accept],
+      [/#{IAC}#{WILL}(.)/m, :reply_dont],
+      [/#{IAC}#{WONT}(.)/m, :ignore],
+      [/#{IAC}#{DO}(.)/m, :reply_wont],
+      [/#{IAC}#{DONT}(.)/m, :ignore],
+      [/#{IAC}#{IP}/, :ignore],
+      [/#{IAC}#{DM}/, :ignore],
+      [/(.)/m, :accept],
+    ]
+
+    # Parse the the command.  Sets @plain and @reply
+
+    def parse_command(command)
       @plain = ''
       @reply = ''
-      state = :idle
-      command.each_char do |c|
-        case state
-        when :idle
-          if c == IAC
-            state = :iac
-          else
-            @plain << c
+      scanner = StringScanner.new(command)
+      while !scanner.eos?
+        SEQUENCES.each do |regexp, method|
+          if scanner.scan(regexp)
+            send method, scanner
+            break
           end
-        when :iac
-          case c
-          when IAC
-            @plain << c
-            state = :idle
-          when WILL
-            state = :will
-          when WONT
-            state = :wont
-          when DO
-            state = :do
-          when DONT
-            state = :dont
-          when IP
-            state = :idle
-          when DM
-            state = :idle
-          else
-            @plain << IAC + c
-            state = :idle
-          end
-        when :will
-          @reply << IAC + DONT + c
-          state = :idle
-        when :wont
-          state = :idle
-        when :do
-          @reply << IAC + WONT + c
-          state = :idle
-        when :dont
-          state = :idle
-        else
-          raise "Unknown state #{state.inspect}"
         end
       end
     end
 
   end