Re: [libredwg] reed solomon

[address@hidden]

Thanks, so you dont have an RS reader yet. I will look into this.
thanks,
mike

On Mon, Aug 30, 2010 at 6:49 PM, Till Heuschmann
<address@hidden> wrote:
> Hi Mike,
>
> I'am working on the R2007 reader which for now just extracts the encoded
> data and ignores the rs parity bytes.
> So I can provide you some data and give you some hints how to read it.
> Attached is the rs data found at offset 0x80 in a .dwg file. The data is
> 0x3d8 bytes long and contains 3 blocks of rs data. One block contains 239
> bytes of data and 16 parity bytes.
> The blocks are interleaved with a factor of 3.
>
> The given data starts like this:
> B3 01 68 D2 58 01 70 67 51 9E 00 7F 26 01 01 80 CD F0 68 A5
>
> ...and so the first rs encoded block starts with:
> B3  D2  70  9E  26  80
>
> the rest of the data (0x3d8 - (3 * 0xFF) = 0xDB) are padded and not rs
> encoded.
>
> If you need some more data feel free to ask. I will push a first version of
> the reader in the next weeks.
>
> Till
>
> Am 30.08.2010 08:02, schrieb address@hidden:
>>
>> hi all,
>> I have started to research into this reed solomon stuff, it does not
>> look that hard.
>>
>> http://en.wikipedia.org/wiki/Reed–Solomon_error_correction
>> http://en.wikipedia.org/wiki/BCH_code
>> http://en.wikipedia.org/wiki/Berlekamp-Massey_algorithm
>> also MIT OCW :
>> http://www.youtube.com/watch?v=Nnj9lHePqKM
>>
>> can you please provide me with a block of pure data that is in RS
>> format and the encoding parameters. I am going to work on a decoder.
>>
>> mike
>>
>>
>
>



-- 
James Michael DuPont
Member of Free Libre Open Source Software Kosova and Albania
flossk.org flossal.org