RE: Base64 question

["John Allen" <jallen@xxxxxxxxxxx>]

Scott,

Thanks for that info, I was hoping to run this on V5R1
But if I can't compile it then I will move it up to V5R2 or
V5R3 and compile it there

I will try base64-encode later today

John


-----Original Message-----
From: Scott Klement [mailto:midrange-l@xxxxxxxxxxxxxxxx] 
Sent: Friday, November 07, 2008 2:14 AM
To: Midrange Systems Technical Discussion
Subject: Re: Base64 question

Call base64_encode() and base64_decode().  Do not use the
old ones, they 
don't work right.

John Allen wrote:
> Scott, 
>
> Maybe I have something wrong in my test code:
> I am testing with "ABC"
> I translate this to ASCII and get the correct value
> X'414243'
> I do Base64 encode and get QkJD
> Then when I decode it I get X'424243'
> Which is BBC
>
> D W$Before        S              8A                       
> D W$After         S             12A                       
> D W$AfterLen      S             10I 0                     
>  *                                                        
> D W$After2        S             12A                       
> D W$AfterLen2     S             10I 0                     
>  *                                                        
> D P$LEN           S              4  0                     
> D P$Table         S             10A                       
>  *                                                        
> C                   eval      W$Before = 'ABC'            
>  * Calculate length of PCL commnd string                  
> C     ' '           CHECKR    W$Before      P$Len         
>  * Convert string to ascii                                
> C                   CALL      'QDCXLATE'                  
> C                   PARM                    P$len

> C                   PARM                    W$Before

> C                   PARM      'QASCII'      P$table

>  *

>  * W$Before = 'ABC'; after translation debug shows
x'414243'
>  /free

>

>      W$AfterLen = B64_Encode( %ADDR(W$Before)

>                             : %LEN(%TRIMR(W$Before))

>                             : %ADDR(W$After)

>                             : %SIZE(W$After) );

>

>      W$AfterLen2 = B64_Decode( %ADDR(W$After)

>                              : %LEN(%TRIMR(W$After))

>                              : %ADDR(W$After2)

>                              : %SIZE(W$After2) );

>

>      *INLR = *ON;

> /end-free
>
> WAfter2 = debug shows x'424243' (which is BBC)
>
>
>
> -----Original Message-----
> From: Scott Klement [mailto:midrange-l@xxxxxxxxxxxxxxxx] 
> Sent: Thursday, November 06, 2008 3:13 PM
> To: Midrange Systems Technical Discussion
> Subject: Re: Base64 question
>
> hi John,
>
> I don't think it makes sense to store in ASCII in the
> database.  After 
> all, you're likely to want to do other things with your
> database besides 
> this one program.
>
> Why not just add code to your RPG program to convert it to
> ASCII prior 
> to base64 encoding it?
>
> Here's a trivial example in ILE RPG, that uses the
> IBM-supplied QDCXLATE 
> program to convert from EBCDIC to ASCII:
>
>       D QDCXLATE        PR
> ExtPgm('QDCXLATE')
>       D   Len                          5p 0 const
>       D   data                     32702a
> options(*varsize)
>       D   table                       10a   const
>
>       D data            s              5
>        /free
>           data = 'Hello';
>           QDCXLATE( %len(data)
>                   : data
>                   : 'QTCPASC' );
>
> The above method is really easy to do, and it works. It
can
> be used with 
> any of the translation tables (*TBL objects) on your
system.
> QTCPASC is 
> an IBM-supplied table that translates to ASCII.
>
> There are two big problems with QDCXLATE:
>
> a) You can't use it to translate a single-byte character
set
> to a double 
> or mixed-byte character set.
>
> b) In order to make it work properly with variant
> characters, you have 
> to find (or create) a table that translates exactly the
way
> you want. 
> (there are many versions of ASCII and many versions of
> EBCDIC.  Which 
> one are you translating from?  Which one are you
translating
> to?)
>
> A more sophisticated method of doing the translation (and
> one that 
> requires more code) is to use the iconv() API.  With
iconv()
> you can 
> provide the exact from/to CCSID and it'll translate
between
> them.  It 
> also lets you work with double-byte and multi-byte
character
> sets.  But 
> the code is more complex, so I'll leave you with the
> QDCXLATE API for 
> now, and if you find that lacking, let me know and I'll
post
> an iconv 
> example.
>
> But, at any rate, ASCII/EBCDIC translation is hardly part
of
> Base64 
> encoding!  Indeed, most of the time you use base64
encoding
> expressly 
> because your data isn't text data!
>
>
>
> John Allen wrote:
> > 1)If I have the value "Hello" in my database field on the
> > System i (in EBCDIC) isn't there some method I can
convert
> > it to an ASCII value before encoding it to Base64 so I
end
> > up with the correct Base64 value the ASCII machine is
> > expecting, or just store it in my database field in ASCII
> > format (although it is actually an EBCDIC System)?
> > Example If the value were 123 in EBCDIC it would be
stored
> > as x'F1F2F3' Could I store it as ASCII x'313233' then
> could
> > it be encoded to Base64 to be read in correctly by ASCII
> > system?