Deflate, Base64Encode, Base64Decode and Inflate

[Gregory M. Sliker]

Hi All,

I am trying to do the following and don't know where things are blowing up.

Step 1. Read a small XML file.
Step 2. Using java.util.zip, Deflate that file.
Step 3. Using Base64, encode the deflated byte array and write it to a
file.
Step 4. Some foolin around stuff goes on not related to the above, coffee
and donuts kind of thing...
Step 5. Using Base64, decode the above, saved file. Note: get an error
here, see below.
Step 6. Using java.util.zip, Inflate the byte array
Step 7. Use the reconstituted XML and continue on with my life in a smiling
manner...

When I have all the pieces put together in 3 files, (Deflate, Inflate and
Base64) I get the following error when I try to Inflate...

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Input
to decode
not an even multiple of 4 characters; pad with =.
at Base64.decode(Base64.java:187)
at DirectInflater.main(DirectInflater.java:24)

The annoying thing is that if I comment out the Base64 steps the
Deflate/Inflate routines work great. If I comment out the Deflate/Inflate
and
just do the Encode/Decode parts it works great too! It's only when I try to
put the pieces together that it chokes.

Does anyone have any experience they could offer? If anyone would like I
can send the source for this "proof of concept". The Inflate and Deflate
code is a modified version of the examples found in a book called Java I/O
by Elliotte Harold and the Base64 code is from Roedy Green's site,
unchanged. The XML file is irrelevant and in fact the code chokes on any
file I give it. I have tried other Base64 examples including the
undocumented Encoder and Decoder in the sun packages, all with the same
result. Any ideas anyone?

Thanks in advance,

Greg Sliker

[Ken Kalish]

That does seem odd, doesn't it? IIRC, the whole point of base64 was to enable
sending pictures and other binary data through 7-bit email gateways. So it
should not have any problem with a zipped file.

Have you verified that the encoded file is in fact a multiple of four? If not,
you can pad the end as a workaround.

[Gregory M. Sliker]

From what I read regarding the Base64 method I would have thought that it
would take care of the padding for me (with "=" as needed). But to answer
your question, no I haven't actually checked to make sure that the file is a
multiple of 4. It works when not used in conjunction with Deflate/Inflate I
just assumed it was fine. If it isn't, I'm not really sure what I can do
since I really don't have any idea where the "corruption" occured,

Thanks for the reply and I'll working away at it.

Greg Sliker

"Ken Kalish" <kk...@javakk.com> wrote in message
news:3b63d8d6...@news.earthlink.net...

[Roedy Green]

On Sat, 21 Jul 2001 09:18:15 -0400, "Gregory M. Sliker"
<gsl...@lightstream.net> wrote or quoted :

>From what I read regarding the Base64 method I would have thought that it
>would take care of the padding for me (with "=" as needed).

my version of Base64 does. See Base64 in the Java glossary.

For more detail, please look up the key words mentioned in this post in
the Java Glossary at: http://mindprod.com/gloss.html

--
Roedy Green, Canadian Mind Products
Custom computer programming since 1963. Ready to take on new work.