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#
# (c) 2017 Aleph Objects, Inc.
#
# The code in this page is free software: you can
# redistribute it and/or modify it under the terms of the GNU
# General Public License (GNU GPL) as published by the Free Software
# Foundation, either version 3 of the License, or (at your option)
# any later version. The code is distributed WITHOUT ANY WARRANTY;
# without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU GPL for more details.
#
import random
import string
class NoisySerialConnection:
"""Wrapper class which injects character noise into data of
a serial connection for testing Marlin's error correction"""
def __init__(self, serial):
self.serial = serial
self.readErrorRate = 0
self.writeErrorRate = 0
def _corruptData(self, data):
"""Introduces a single character error on a string"""
badChar = random.choice(string.ascii_letters)
badChar = badChar if isinstance(data, str) else badChar.encode()
if len(data) == 0:
return data
if len(data) == 1:
return badChar
charToCorrupt = random.randint(0, len(data) - 1)
return data[:charToCorrupt] + badChar + data[charToCorrupt+1:]
def write(self, data):
if(random.random() < self.writeErrorRate):
data = self._corruptData(data)
self.serial.write(data)
def readline(self):
data = self.serial.readline()
if(random.random() < self.readErrorRate):
data = self._corruptData(data)
return data
def flush(self):
self.serial.flush()
def close(self):
self.serial.close()
def setWriteErrorRate(self, badWrites, totalWrites):
"""Inserts a single character error into every badWrites out of totalWrites"""
self.writeErrorRate = float(badWrites)/float(totalWrites)
def setReadErrorRate(self, badReads, totalReads):
"""Inserts a single character error into every badReads out of totalReads"""
self.readErrorRate = float(badReads)/float(totalReads)