Re: base64 coding for zsh ?

["Brian K. White" <brian@aljex.com>]

----- Original Message ----- 
From: "Marc Chantreux" <marc.chantreux@ulpmm.u-strasbg.fr>
To: "zsh-users" <zsh-users@sunsite.dk>
Sent: Wednesday, September 13, 2006 11:08 AM
Subject: Re: base64 coding for zsh ?


le 12/09/2006,
Bart Schaefer nous crivait :
> It's about 50 lines of readably-formatted C code to write a base64
> decoder,

so i'll write my first zsh module. It's added to my todo list.

> slightly more than that to write the encoder, not counting the
> lookup tables. It could be done in shell script, but it would be very
> slow and probably not worth the effort.

ok, i give this solution away.

> alias enB64="perl -MMIME::Base64 -e 'print encode_base64(shift @ARGV)'"
> alias deB64="perl -MMIME::Base64 -e 'print decode_base64(shift @ARGV)'"

well ... i think perl is quite huge for this problem. I'll use openssl
as temporary hack.

alias B64enc='openssl base64'
alias B64dec='openssl base64 -d'

thanks for help.

regards.

------------

I've been using the stand-alone:
http://www.fourmilab.ch/webtools/base64/

I never realised I already had it in openssl.
Thanks for the tip.

This led me to see what else I might already have or could get in a ready 
made package rather than having to use a source.
(I do need this util in some form on every box and previously all my boxes 
were SCO OpenServer and I had been using the fourmilab source for years.)

Then I decided to run a few simple time tests, since this gets used a lot in 
various system() commands in application code and cgi scripts etc...
I expected the simple plain base64 util to be the fastest but I was wrong:
In each case I repeated the same command many times and always got almost 
exactly the same results, that is, +- 0m0.004 of the numbers shown so these 
are representative not just a fluke or caching effects or effects of the os 
being busy elsewhere.

the fourmilab source:
nj4:~ # time base64 </boot/vmlinuz >/dev/null

real    0m0.074s
user    0m0.072s
sys     0m0.000s

openssl:
nj4:~ # time opsnssl base64 </boot/vmlinuz >/dev/null
-bash: opsnssl: command not found

real    0m0.001s
user    0m0.000s
sys     0m0.000s

mimencode comes in the metamail package:
nj4:~ # time mimencode </boot/vmlinuz >/dev/null

real    0m0.078s
user    0m0.076s
sys     0m0.004s


gmime-uuencode:
It actually does base64 not uuencode if you give it the -m or --base64 
option.
It comes in the gmime package.
It prepends and appends some junk to the actual base64 output so it's 
inconvenient for me to actually use:
    nj4:~ # echo this is a test |gmime-uuencode -m -
    begin-base64 600 -
    dGhpcyBpcyBhIHRlc3QK
    ====
    nj4:~ #
As for the speed:
nj4:~ # time gmime-uuencode -m - </boot/vmlinuz >/dev/null

real    0m0.009s
user    0m0.008s
sys     0m0.000s

Ooenssl destroys the rest.
So even though I have the dedicated util it's actually better to use 
openssl.
As a side benefit, thats one less special thing to maintain on all my boxes.


On a related note. I had/have a need for a standalone url encoder/decoder 
and made one myself, then receive the help of someone else to make it into a 
proper util with man page and getopts() and basic sanity checking etc... The 
source is here. I never bothered to make linux binaries except for myself 
yet but it's such basic code it builds with no problems anywhere.
http://www.aljex.com/bkw/sco/#urldec

Does anyone know of an already existing util to do that?
I can't imagine how something so basic can be made 78 times faster but I 
would have said the same thing about base64 until now also.
Note: I'd like it to work as a filter like cat, like all the utils above.
In fact, my util has options to do both, work as a filter or take a string 
on the command line.
Thanks.

btw, compared to above, ick...
nj4:~ # time urlenc </boot/vmlinuz >/dev/null

real    0m0.332s
user    0m0.332s
sys     0m0.000s


Brian K. White  --  brian@aljex.com  --  http://www.aljex.com/bkw/
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