matlab crc8,了解CRC8 SAE J1850（正常）与“零”的结果

defcrc(msg,div,code=11111111):"""Cyclic Redundancy Check

Generates an error detecting code based on an inputted message

and divisor in the form of a polynomial representation.

Arguments:

msg: The input message of which to generate the output code.

div: The divisor in polynomial form. For example, if the polynomial

of x^3 + x + 1 is given, this should be represented as 1011 in

the div argument.

code: This is an option argument where a previously generated code may

be passed in. This can be used to check validity. If the inputted

code produces an outputted code of all zeros, then the message has

no errors.

Returns:

An error-detecting code generated by the message and the given divisor.

"""# Append the code to the message. If no code is given, default to 1111111# Uncomment every occurence of msg_XORIN if not CRC-8 SAE J1850msg_XORIN=[]# XOR the input before appending the codemsg_XORIN=[str((int(msg[i])+1)%2)foriinrange(len(list(msg)))]msg=msg_XORIN

div=list(div)msg=list(msg)+list(code)# Convert msg and div into list form for easier handling# Loop over every message bit (minus the appended code)foriinrange(len(msg)-len(code)):# If that messsage bit is not one, shift until it is.ifmsg[i]==1:forjinrange(len(div)):# Perform modulo 2 ( == XOR) on each index of the divisormsg[i+j]=str((int(msg[i+j])+int(div[j]))%2)# Output the last error-checking code portion of the message generatedreturn.join(msg[-len(code):])

defcrc(msg,div,code=11111111):"""Cyclic Redundancy Check Generates an error detecting code based on an inputted message and divisor in the form of a polynomial representation. Arguments: msg: The input message of which to generate the output code. div: The divisor in polynomial form. For example, if the polynomial of x^3 + x + 1 is given, this should be represented as 1011 in the div argument. code: This is an option argument where a previously generated code may be passed in. This can be used to check validity. If the inputted code produces an outputted code of all zeros, then the message has no errors. Returns: An error-detecting code generated by the message and the given divisor. """# Append the code to the message. If no code is given, default to 1111111# Uncomment every occurence of msg_XORIN if not CRC-8 SAE J1850msg_XORIN=[]# XOR the input before appending the codemsg_XORIN=[str((int(msg[i])+1)%2)foriinrange(len(list(msg)))]msg=msg_XORIN div=list(div)msg=list(msg)+list(code)# Convert msg and div into list form for easier handling# Loop over every message bit (minus the appended code)foriinrange(len(msg)-len(code)):# If that messsage bit is not one, shift until it is.ifmsg[i]==1:forjinrange(len(div)):# Perform modulo 2 ( == XOR) on each index of the divisormsg[i+j]=str((int(msg[i+j])+int(div[j]))%2)# Output the last error-checking code portion of the message generatedreturn.join(msg[-len(code):])