Re: Base64 question

["Charles Wilt" <charles.wilt@xxxxxxxxx>]

For option #1, use iconv()

Here's a past example from Scott.
http://archive.midrange.com/rpg400-l/200403/msg00085.html

HTH,
Charles

On Thu, Nov 6, 2008 at 2:20 PM, John Allen <jallen@xxxxxxxxxxx> wrote:

> Scott,
>
> Thanks for the explanation; I understand it for the most
> part.
>
> However I do have a few more questions.
>
> 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?
>
>  2) Somehow translate the EBCDIC field contain "Hello" to
> ASCII then encode it to Base64. To get the Base64 value the
> ASCII machine is looking for.
>
> 3) Store the value "Hello" in a file in the IFS, Encode it
> to Base64 and sent it to the ASCII machine?
>
> I would prefer #1, is any of this possible?
> Or am I totally confused?
>
> John
>
>
>
> -----Original Message-----
> From: Scott Klement [mailto:midrange-l@xxxxxxxxxxxxxxxx]
> Sent: Thursday, November 06, 2008 1:40 PM
> To: Midrange Systems Technical Discussion
> Subject: Re: Base64 question
>
> Hi John,
>
> The purpose behind base64 is to allow binary data to be sent
> through a
> text transfer medium.  For example, if you have a JPEG
> picture and want
> to send it through e-mail, you have a problem.  Pictures
> aren't made up
> of letters and numbers, instead the actual bit values of the
> bytes
> control what the picture looks like.  However, e-mail was
> designed for
> text.  If you send e-mail from a computer running ASCII to a
> computer
> running EBCDIC, all of the bytes in the message will be
> translated from
> ASCII to EBCDIC -- so a picture would become a corrupt mess.
>
> Base64 is a solution to that problem.   Base64 takes the
> actual bit
> values that make up a string of data, and converts them to
> to a
> text-safe format.  The text can then be translated to
> ASCII/EBCDIC/Unicode, whatever, it doesn't matter.  When
> it's decoded,
> the data will be decoded back to the exact same binary
> values that you
> started with.
>
> That being the case, a text string encoded on an EBCDIC
> platform will
> CERTAINLY encode to a different string than a text string
> encoded on an
> ASCII platform!   Of course it will, since the underlying
> bit values are
> different.
>
> If you take the string 'Hello' and encode it on an EBCDIC
> platform,
> you've encoded x'C885939396' into base64.  When you decode
> it on an
> ASCII platform, it'll decode to x'C885939396' -- which is
> NOT the word
> Hello in ASCII (If it did that, there'd be no point to
> base64) but
> rather, it's the exact same bit values you started with...
>
> Hope you understand.
>
> John Allen wrote:
> > I am doing a test to see of I can convert a character
> string
> > to B64 from within an RPG program
> >
> > There are programs on the web that convert files in the
> IFS,
> > but I need to convert a database field
> >
> >
> >
> > So I am using a B64 encode/decode program from Scott
> Klement
> > (Thanks Scott)
> >
> > However I am getting a completely different value then
> what
> > I get using a Web based B64 encode decode program
> >
> > AND when I try to convert it back it does not convert back
> > correctly
> >
> >
> >
> > Can anyone point me to what I may be doing wrong?
> >
> > Does the encode.decode expect ASCII characters?
> >
> > Should the example below work fine?
> >
> >
> >
> > W$Before = 'ABCDEFGH';
> >
> >
> >
> > W$AfterLen = B64_Encode( %ADDR(W$Before)
> >
> >                        : %LEN(%TRIMR(W$Before))
> >
> >                        : %ADDR(W$After)
> >
> >                        : %SIZE(W$After) );
> >
> >
> >
> > (Using Debug I see that W$AFTER = 'wsLDxcXGxMgg')
> >
> > (Web based encodes to QUJDREVGR0gNCg==)
> >
> >
> >
> >  W$AfterLen2 = B64_Decode( %ADDR(W$After)
> >
> >                          : %LEN(%TRIMR(W$After))
> >
> >                          : %ADDR(W$After2)
> >
> >                          : %SIZE(W$After2) );
> >
> >
> >
> >
> >
> > (Using Debug I see that decodes back to W$AFTER2 =
> > 'BBCEEFDH-   ')
> >
> >
> >
> > Any ideas on what I might be doing wrong?
> >
> >
> >
> > Thanks
> >
> >
> >
> > John
>
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