Get frontend statistics using python

festat.py

import sys
import fcntl
import ctypes

_IOC_NRBITS = 8
_IOC_TYPEBITS = 8
_IOC_SIZEBITS = 14
_IOC_DIRBITS = 2

_IOC_NRSHIFT = 0
_IOC_TYPESHIFT = _IOC_NRSHIFT + _IOC_NRBITS
_IOC_SIZESHIFT = _IOC_TYPESHIFT + _IOC_TYPEBITS
_IOC_DIRSHIFT = _IOC_SIZESHIFT + _IOC_SIZEBITS

_IOC_NONE = 0
_IOC_WRITE = 1
_IOC_READ  = 2

def _IOC(dir_, type_, nr, size):
    return (
        ctypes.c_int32(dir_ << _IOC_DIRSHIFT).value |
        ctypes.c_int32(ord(type_) << _IOC_TYPESHIFT).value |
        ctypes.c_int32(nr << _IOC_NRSHIFT).value |
        ctypes.c_int32(size << _IOC_SIZESHIFT).value)

def _IOC_TYPECHECK(t):
    return ctypes.sizeof(t)

def _IO(type_, nr):
    return _IOC(_IOC_NONE, type_, nr, 0)

def _IOW(type_, nr, size):
    return _IOC(_IOC_WRITE, type_, nr, _IOC_TYPECHECK(size))

def _IOR(type_, nr, size):
    return _IOC(_IOC_READ, type_, nr, _IOC_TYPECHECK(size))

def _IOWR(type_, nr, size):
    return _IOC(_IOC_READ | _IOC_WRITE, type_, nr, _IOC_TYPECHECK(size))

enum = ctypes.c_uint
fe_status_t = enum
FE_HAS_SIGNAL = 0x01
FE_HAS_CARRIER = 0x02
FE_HAS_VITERBI = 0x04
FE_HAS_SYNC = 0x08
FE_HAS_LOCK = 0x10
FE_TIMEDOUT = 0x20
FE_REINIT = 0x40

FE_READ_STATUS = _IOR('o', 69, fe_status_t)
FE_READ_BER = _IOR('o', 70, ctypes.c_uint32)
FE_READ_SIGNAL_STRENGTH = _IOR('o', 71, ctypes.c_uint16)
FE_READ_SNR = _IOR('o', 72, ctypes.c_uint16)
FE_READ_UNCORRECTED_BLOCKS = _IOR('o', 73, ctypes.c_uint32)

class Frontend(object):
    def __init__(self, fd):
        self._fd = fd

    def _ioctlGet(self, query, c_type):
        result = c_type()
	try:
        	fcntl.ioctl(self._fd, query, result)
	except:
		print "exception using %s" % query
        return result

    def getStatus(self):
        return self._ioctlGet(FE_READ_STATUS, fe_status_t).value

    def getBitErrorRate(self):
	return self._ioctlGet(FE_READ_BER, ctypes.c_uint32).value

    def getSignalNoiseRatio(self):
        return self._ioctlGet(FE_READ_SNR, ctypes.c_uint16).value

    def getSignalStrength(self):
        return self._ioctlGet(FE_READ_SIGNAL_STRENGTH, ctypes.c_uint16).value

    def getUncorrectedBlockCount(self):
	return self._ioctlGet(FE_READ_UNCORRECTED_BLOCKS, ctypes.c_uint32).value

dev = "/dev/dvb/adapter0/frontend1"
fe = Frontend(open(dev, 'r'))
i = 0
while i<5000:
	i += 1
	sys.stdout.write("\r%g%% " % (i*100/5000.0))
	#print fe.getBitErrorRate()
	#print fe.getStatus()
	#print fe.getSignalNoiseRatio()
	# this one causes signal error
	sys.stdout.write("%d" % fe.getSignalStrength())
	sys.stdout.flush()
	#print fe.getUncorrectedBlockCount()

print "\n...the end..."