Thanks..
I am aware of these things....
but i don't know from where to start.
suppose the mail has following structure
1 (mail)
1.1 (jpg file)
1.2 (another mail so it has its own header)
1.2.1 (application)
1.2.2 (video)
...

so here i have to decode first msg. then second msg(1.2) to get its attachments.
now compress attachments put them back in second msg and again put the second msg in 1st msg...
so can i decode msgs n create files or something else..??