def decode(self, message: list, error_size: int) -> str:
"""
:param message: 具有奇偶校验位的消息，它可能包含错误，也可能不包含错误
:param error_size: 错误符号的数目
:return:一个解码的消息，如果可能的话
"""
buffer = copy.deepcopy(message)
#首先检查是否有擦除
erasures = []
for position in range(len(buffer)):
if buffer[position] < 0:
buffer[position] = 0
erasures.append(position)
# 错误太多 退出
if len(erasures) > error_size:
raise ReedSolomonError("Too many erasures")
# 计算伴随多项式
syndrome_polynomial = Polynomial.syndromePolynomial(buffer, error_size)
if max(syndrome_polynomial) == 0:
return bytearray(buffer[:-error_size]).decode('utf-8')
forney_syndromes = self.forneySyndromes(syndrome_polynomial, erasures, buffer)
error_list = self.findErrors(forney_syndromes, len(message))
if error_list is None:
raise ReedSolomonError("Could not find errors")
decoded_symbols = self.correct(buffer, syndrome_polynomial, (erasures + error_list))
return bytearray(decoded_symbols[:-error_size]).decode('utf-8')
def decode(self, message: list, error_size: int) -> str:
"""
:param message: a message with parity bits which might or might not contain errors
:param error_size: the number of error symbols
:return: a decoded message if possible
"""
buffer = copy.deepcopy(message)
# First check if there's any erasures
erasures = []
for position in range(len(buffer)):
if buffer[position] < 0:
buffer[position] = 0
erasures.append(position)
# Quit if we have too many erasures
if len(erasures) > error_size:
raise ReedSolomonError("Too many erasures")
# Calculate the syndrome polynomial
syndrome_polynomial = Polynomial.syndromePolynomial(buffer, error_size)
if max(syndrome_polynomial) == 0:
return bytearray(buffer[:-error_size]).decode('utf-8')
# Calculate the Forney syndromes - removes the erasures from the syndrome polynomial
forney_syndromes = self.forneySyndromes(syndrome_polynomial, erasures,
buffer)
# Calculate a list of errors in the message using Berlekamp-Massey algorithm
error_list = self.findErrors(forney_syndromes, len(message))
if error_list is None:
raise ReedSolomonError("Could not find errors")
# Correct the erasures and errors in the message using the Forney algorithm
decoded_symbols = self.correct(buffer, syndrome_polynomial,
(erasures + error_list))
return bytearray(decoded_symbols[:-error_size]).decode('utf-8')
