#1/usr/bin/env python
# coding: utf-8
# copyright Michael Weber avr at xmw.de 2008
# released with GNU GPL

import os, tty, select

class serial:
	def __init__(self, linkname, linkspeed):
	    self.linkname = linkname
	    self.linkspeed = linkspeed
	    self.timeout = 1
	    self.link = os.open(linkname, os.O_RDWR)
	    tty.setraw(self.link)
	    mode = tty.tcgetattr(self.link)
	    mode[tty.ISPEED] = mode[tty.OSPEED] = linkspeed
	    tty.tcsetattr(self.link, tty.TCSAFLUSH, mode)

	def read(self, n, timeout=None):
	    if not timeout:
		timeout = self.timeout
	    i = 0
	    data = []
	    while len(data) < n:
		iset, oset, eset = select.select([self.link], [], [], timeout)
		if iset == []:
		    return data
		data.append(os.read(self.link, 1))
	    return data

	def write(self, data):
	    os.write(self.link, data)

	def __del__(self):
	    os.close(self.link)