diff --git a/shadowsocks/ioloop.py b/shadowsocks/ioloop.py
new file mode 100644
index 0000000..b72e999
--- /dev/null
+++ b/shadowsocks/ioloop.py
@@ -0,0 +1,284 @@
+#coding:utf8
+"""
+Created on Oct 24, 2013
+
+@author: xing
+@
+"""
+
+import sys
+import os
+import select
+import logging
+import socket
+import errno
+
+try:
+    from cStringIO import StringIO
+except ImportError, e:
+    from StringIO import StringIO
+
+try:
+    from select import epoll as pollerFact
+    MY_POLLEV_IN = select.EPOLLIN
+    MY_POLLEV_PRI = select.EPOLLPRI
+    MY_POLLEV_OUT = select.EPOLLOUT
+    MY_POLLEV_ERR = select.EPOLLERR
+except ImportError, e:
+    print >> sys.stderr, e
+    pollerFact = select.poll
+    MY_POLLEV_IN = select.POLLIN
+    MY_POLLEV_PRI = select.POLLPRI
+    MY_POLLEV_OUT = select.POLLOUT
+    MY_POLLEV_ERR = select.POLLERR
+
+
+class IOLoopError(Exception):
+    pass
+
+
+class IOLoop(object):
+    _instance = None
+
+    @classmethod
+    def instance(cls):
+        if not cls._instance:
+            cls._instance = cls()
+        return cls._instance
+
+    def __init__(self):
+        logging.debug('IOLoop.__init__()')
+        self._fd_map = {}
+        self._poller = pollerFact()
+
+    def add_handler(self, fd, handler, m_read=False, m_write=False):
+        if fd in self._fd_map:
+            raise IOLoopError(u'fd(%s) handler is %s' % (fd, self._fd_map[fd]))
+
+        flags = MY_POLLEV_ERR
+    	if m_read:
+	    flags |= MY_POLLEV_IN | MY_POLLEV_PRI 
+    	if m_write:
+	    flags |= MY_POLLEV_OUT
+
+        self._poller.register(fd, flags)
+        #self._set_nonblocking(fd)
+        self._fd_map[fd] = handler
+        logging.debug('len(ioloop._fd_map) = %d', len(self._fd_map))
+
+    def remove_handler(self, fd):
+        handler = self._fd_map.pop(fd)
+        del handler
+        self._poller.unregister(fd)
+        logging.debug('unregister %d,current len(ioloop._fd_map) = %d', fd, len(self._fd_map))
+
+
+    def modify_handler(self, fd, handler, m_read=False, m_write=False):
+		self.remove_handler(fd)
+		self.add_handler(fd, handler, m_read=False, m_write=False)
+
+    def wait_events(self, timeout):
+        events_list = self._poller.poll(timeout)
+        for fd, events in events_list:
+            if fd not in self._fd_map:
+                logging.warn('fd %d not in fd_map', fd)
+                self._poller.unregister(fd)
+                continue
+            handler = self._fd_map[fd]
+            if events & MY_POLLEV_ERR:
+                # logging.debug("fd[%s] events MY_POLLEV_ERR | MY_POLLEV_HUP", fd)
+                handler.handle_error(events)
+            elif events & MY_POLLEV_IN or events & MY_POLLEV_PRI:
+                # logging.debug("fd[%s] events MY_POLLEV_IN | MY_POLLEV_PRI", fd)
+                handler.handle_read()
+            elif events & MY_POLLEV_OUT:
+                # logging.debug("fd[%s] events MY_POLLEV_OUT", fd)
+                handler.handle_write()
+
+    #@staticmethod
+    #def _set_nonblocking(fd):
+    #    flags = fcntl.fcntl(fd, fcntl.F_GETFL)
+    #    fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK)
+
+
+class IOStream(object):
+    def __init__(self, obj):
+        self._wbuf = StringIO()
+        self._fd = obj.fileno()
+        self._obj = obj
+
+    def read(self, *args, **kwargs):
+        # logging.debug("IOStream[%s].read()", self._obj.fileno())
+        return self._obj.read(*args, **kwargs)
+
+    def write(self, s):
+        """write to buffer, unit IOHandler.handle_write() call real_write() to write it"""
+        self._wbuf.write(s)
+
+    def real_write(self):
+        if self._wbuf.tell() > 0:
+            self._obj.write(self._wbuf.getvalue())
+            self._wbuf.truncate(0)
+
+    def close(self):
+        return self._obj.close()
+
+    def fileno(self):
+        return self._fd
+
+
+class SocketStream(IOStream):
+    def read(self, size):
+        return self._obj.recv(size)
+
+    def real_write(self):
+        if self._wbuf.tell() > 0:
+            data = self._wbuf.getvalue()
+            try:
+                self._obj.sendall(data)
+            except socket.error, _e:
+                if _e.errno in (errno.EWOULDBLOCK, errno.EAGAIN):
+                    return 
+
+            self._wbuf.truncate(0)
+    
+    def close(self):
+        if isinstance(self._obj, socket._socketobject):
+            self._obj.shutdown(socket.SHUT_RDWR)
+        self._obj.close()
+
+
+class BaseHandler(object):
+    monitor_read = True
+    monitor_write = True
+    def __init__(self):
+        raise
+
+    def handle_read(self):
+        raise
+
+    def handle_write(self):
+        raise
+
+    def handle_error(self):
+        raise
+
+
+class IOHandler(BaseHandler):
+    monitor_read = True
+    monitor_write = True
+    def __init__(self, ioloop, iostream):
+        self._ioloop = ioloop
+        self._ios = iostream
+        self._fd = self._ios.fileno()
+
+    def handle_read(self):
+        """fd 可读事件出现"""
+        # logging.debug("read from fd %s", self._fd)
+        try:
+            s = self.do_stream_read()
+            if len(s) == 0:
+                logging.debug('iostream[%s].read() return len(s) == 0, close it', self._fd)
+                self._ioloop.remove_handler(self._fd)
+                self._ios.close()
+            return s
+        except socket.error, _e:
+            if _e.errno in (errno.EWOULDBLOCK, errno.EAGAIN):
+                logging.debug('socket error, %s', _e)
+                return
+            else:
+                raise
+
+    def do_stream_read(self, size=None):
+        # 定义这个方法是为了方便重载
+        if size:
+            return self._ios.read(size)
+        else:
+            return self._ios.read()
+
+    def handle_write(self):
+        """fd 可写事件出现"""
+        self._ios.real_write()
+
+    def handle_error(self, events):
+        logging.error("handle_error fd(%s)", self._fd)
+        raise IOLoopError("io error: %x" % events)
+
+
+class SimpleCopyFileHandler(IOHandler):
+    monitor_read = True
+    monitor_write = True
+    def __init__(self, outfile, *args, **kwargs):
+        super(self.__class__, self).__init__(*args, **kwargs)
+        self._outfile = outfile
+        self._outfp = open(self._outfile, 'wb')
+        self.last_len = 0
+
+    def handle_read(self):
+        s = super(self.__class__, self).handle_read()
+        if s:
+            self._outfp.write(s)
+            curr_len = self._outfp.tell()
+            if curr_len - self.last_len >= 1024*1024:
+                self._ios.write(str(curr_len/1024/1024)+'M\n')
+                self.last_len = curr_len
+
+    def do_stream_read(self, size=4096):
+        # 定义这个方法是为了方便重载
+        return self._ios.read(size)
+
+
+class SimpleAcceptHandler(BaseHandler):
+    monitor_read = True
+    monitor_write = False
+    def __init__(self, ioloop, srv_socket):
+        self._ioloop = ioloop
+        self._srv_socket = srv_socket
+
+    def handle_read(self):
+        cli_socket, cli_addr = self._srv_socket.accept()
+        logging.debug("accept connect[%s] from %s:%s" % (
+            cli_socket.fileno(), cli_addr[0], cli_addr[1]))
+        cli_socket.setblocking(0)
+        #handler = SimpleCopyFileHandler('/dev/null', self._ioloop, SocketStream(cli_socket))
+        handler = SimpleCopyFileHandler('/data/SimpleCopyFileHandler.fd%s.out.txt' % (
+            cli_socket.fileno()), self._ioloop, SocketStream(cli_socket))
+        self._ioloop.add_handler(cli_socket.fileno(), handler, m_read=True, m_write=False)
+
+
+def test_pipe():
+    ioloop = IOLoop()
+    io_stdin = IOStream(sys.stdin)
+
+    import random
+    fifo_filename = ''.join([chr(random.randint(0, 25)+ord('A')) for _ in range(10)])
+    fifo_filepath = os.path.join('/tmp', fifo_filename)
+    if not os.path.exists(fifo_filepath):
+        os.mkfifo(fifo_filepath)
+    io_pipe = IOStream(open(fifo_filepath, 'rb+'))
+    import atexit
+    atexit.register(lambda: os.unlink(fifo_filepath))
+
+    ioloop.add_handler(io_pipe.fileno(), IOHandler(ioloop, io_pipe), m_read=True, m_write=True)
+    ioloop.add_handler(io_stdin.fileno(), IOHandler(ioloop, io_stdin), m_read=True, m_write=True)
+    while True:
+        ioloop.wait_events(0.1)
+
+
+def test_copyfilehandler():
+    ioloop = IOLoop()
+    import socket
+    sock = socket.socket()
+    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+    sock.setblocking(0)
+    sock.bind(("0.0.0.0", 64433))
+    logging.info("listing on %s", str(sock.getsockname()))
+    sock.listen(1024)
+    ioloop.add_handler(sock.fileno(), SimpleAcceptHandler(ioloop, sock), m_read=True)
+    while True:
+        ioloop.wait_events(0.1)
+
+if __name__ == '__main__':
+    logging.basicConfig(level=logging.DEBUG)
+    #logging.basicConfig(level=logging.INFO)
+    test_copyfilehandler()