[erlang-questions] checksum calculation
Mon Apr 6 11:34:51 CEST 2009
If it is not a very good solution, would you like to suggest a better one, for me and the other readers ?
>On 6 Apr 2009, at 11:29 am, Gamoto wrote:
>> I have a string of bytes and would like to compute the checksum
>> which is the xor of all bytes.
>> Let S the string, N the current byte
>> checksum( <<N,Rest>>,Csum) ->
>> checksum(Rest,Csum bxor N);
>> The problems are: I don't know how to start (checksum(<<S>>) ???)
>> and how to finish !
> checksum(Binary, 0).
>checksum(<<>>, Sum) ->
>checksum(<<Byte,Rest/binary>>, Sum) ->
> checksum(Rest, Sum bxor Byte).
>> First of all, is it the correct approach ?
>> (I suppose I rather should make Csum Exclusive-OR N modulo 8 ???)
>The exclusive-OR of any number of bytes is still just one byte.
>Of course this isn't a very _good_ checksum,
>but that's another issue.
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