flip weird behaviour

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1

Hello all,I’m doing some tests with qcrypt and openssl.I defined, using the qcrypt doc, two a function sha512 in this way:hash:qcrypt 2: (hash;2)sha512:{hash[x;“sha512”]}sha512 returns type is 4h.Then, I created a dictionary in this way:tstampauthkey!(10;sha512[“3”])and this is the outputtstamp | 10authkey| 0xcf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3eBut, if I do a flip of this dictionary: I have this:tstamp authkey--------------10 cf10 8310 e110 3510 7e10 ef10 b810 bd10 f110 54etc…why ?Is it possible to put the entire sha512 result in the column authkey?thanks,Fausto

2

Hi Fausto,

If you enlist the result of your sha512 it should put the entire result into the column:

tstampauthkey!(10;enlist sha512[“3”])

gives an output of

tstamp | 10

authkey| ,0xcf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e

and flipping this gives

tstamp authkey

10     0xcf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e

Hope this helps,

Dan

3

Hello Dan,thanks. The enlist sure helps :-)But I still cannot figure out why flip without enlist did in that way.thanks,faustoIl giorno gio 11 ott 2018 alle ore 11:25 ha scritto:>> Hi Fausto,>> If you enlist the result of your sha512 it should put the entire result into the column:>> tstampauthkey!(10;enlist sha512[“3”])>> gives an output of>> tstamp | 10> authkey| ,0xcf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e>> and flipping this gives>> tstamp authkey> -----------------------------------------------------------------------------------------------------------------------------------------> 10 0xcf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e>> Hope this helps,> Dan>> On Thursday, October 11, 2018 at 10:15:49 AM UTC+1, Fausto Saporito wrote:>>>> Hello all,>>>> I’m doing some tests with qcrypt and openssl.>> I defined, using the qcrypt doc, two a function sha512 in this way:>>>> hash:qcrypt 2: (hash;2)>> sha512:{hash[x;“sha512”]}>>>> sha512 returns type is 4h.>> Then, I created a dictionary in this way:>>>> tstampauthkey!(10;sha512[“3”])>>>> and this is the output>>>> tstamp | 10>> authkey| 0xcf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e>>>> But, if I do a flip of this dictionary: I have this:>>>> tstamp authkey>> -------------->> 10 cf>> 10 83>> 10 e1>> 10 35>> 10 7e>> 10 ef>> 10 b8>> 10 bd>> 10 f1>> 10 54>> etc…>>>> why ?>>>> Is it possible to put the entire sha512 result in the column authkey?>>>> thanks,>> Fausto>> –>

Submitted via Google Groups

4

This seems to explain it:
https://code.kx.com/q4m3/8_Tables/ - If you create a table as the flip of a column dictionary, item-wise extension is performed when the column dictionary is flipped into a table.

This means that if one of the values is not a list, it will be duplicated to fill the whole column. In your case, you want the opposite, which is enforced by the enlist.



tstamp is an atom, authkey is a list of bytes, just like 2 3 is a list of long integers:


q)flipab!(1;2 3)

a b

—

1 2

1 3


5

This is a feature of flip …it fills an atom out to the same length as the list

q)flip (1;1 2 3)

1 1

1 2

1 3

It did the same with your atom and list of bytes. 

Terry

6

Hello Terry and JW

thanks. It’s crystal clear now..

Regards

Fausto

Inviato da iPhone

Il giorno 11 ott 2018, alle ore 21:08, JW Buitenhuis <jwbuitenhuis@gmail.com> ha scritto:

This seems to explain it:
https://code.kx.com/q4m3/8_Tables/ - If you create a table as the flip of a column dictionary, item-wise extension is performed when the column dictionary is flipped into a table.

This means that if one of the values is not a list, it will be duplicated to fill the whole column. In your case, you want the opposite, which is enforced by the enlist.



tstamp is an atom, authkey is a list of bytes, just like 2 3 is a list of long integers:


q)flipab!(1;2 3)

a b

—

1 2

1 3