RE: FN-FORUM: Anyone up for a little number puzzle?

date posted 18th January 2008 15:54

> -----Original Message-----
> Hi Guys,
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> I have a small issue, I have third party piece of software that stores
> data in mySQL. It has an invoice table and an invoice_items table
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> The tables are linked together using the invoice id field but the
> original programmer has encoded the invoice id from the invoice table
> and saved the encoded version in the invoice items table. The whole =
php
> application has been zend encoded so I can't check the code for the
> answer.
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> What I'm trying to do is simply create a report using the data. But I
> can't match them up unless I can understand the encoding method.
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> What I have at the moment is this when comparing the invoice id values
> with the encoded values
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> 1 =3D %A4
> 2 =3D %A7
> 3 =3D %A6
> 4 =3D %A1
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> However
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> 10 =3D %A4%98
> 11 =3D %A4%99 NOT %A4%A4 as expected
> 12 =3D %A4%9A
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> And
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> 1024 =3D %A4%98%C4%C0 (Again not consistent)
>=20


So far in WAUK we have gotten this far with it, a php function that =
encodes the numbers 0 to 9 in the right way=20

function encode($i){
$base =3D 0xA; //init base
$i =3D $i ^ 0xF; //XOR with binary 1111
$i =3D $i ^ $base; //XOR with base
$i =3D $i ^ ($base