[erlang-questions] A pointless problem?
Sat Nov 17 18:39:45 CET 2012
Ah - insight. Endianness did occur to me as a problem but I think I maybe went "too far" in compensating for it previously.
From the tests now I can see that it's the Key endianness that is the remaining issue...
Thank you so much!
On Nov 17, 2012, at 11:28 AM, Dmitry Kolesnikov <dmkolesnikov@REDACTED> wrote:
> This looks as endianness problem. You have to keep in-mind that binaries is big-endian by default, which contrasts with C memory. You have to be very careful of C algorithms mapping.
> I've made a small fixes to int32list_xxx routines (see bold text):
> int32list_from_binary(Bin) ->
> int32list_from_binary(Bin, ).
> int32list_from_binary(<<X:32/little, Bin/binary>>, Acc) ->
> int32list_from_binary(Bin, [X|Acc]);
> int32list_from_binary(<<>>, Acc) ->
> int32list_to_binary(List) ->
> list_to_binary([<<X:32/little>> || X <- List]).
> Some of tests got passed. Unfortunately, some of tests are failed I hope you can easily validate rest of you code agains endian.
> Best Regards,
> On Nov 17, 2012, at 7:02 PM, Steve Davis wrote:
>> I am intrigued by what is arguably a pointless problem.
>> Looking at the tiny encryption algorithm aka XXTEA it seemed easy enough to implement in Erlang. I have an implementation (attached with source and all references inside the module) which encodes and decodes successfully... BUT the cipher text doesn't match the test vectors...
>> What makes this pointless is that I should "just make it a NIF" etc. But it's likely that I am misunderstanding some aspect of either Erlang or C, however I am confounded as to what that problem is... why does the attached implementation not generate the same ciphertext as in the test vectors from the C implementation? Can anyone spot my error?
>> erlang-questions mailing list
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