[RFC] LZO support

[Szymon Janc]

Hello,

I've implemented support for LZO in grub, this includes:
- import of minilzo library (from [1])
- support for LZO (de)compression in btrfs (compress=lzo mount option)
- lzopio - for reading lzop compressed files

Some comments:
- with this code one is able to boot from btrfs partition that was mounted
  with compress=lzo, also did some tests with grub-fstest (crc, testload) on
  some various files, seems to be working fine,
- lzopio works ok with grub-fstest (crc, testload), also able to load modules 
  compressed with lzop, but compressing all modules and doing 
  grub-install --modules=lzopio fails to boot, still need to investigate that
- lzopio have room for speed optimisation i.e. decompressing directly to 
  target buffer when possible, currently there is always memcpy from temp
  buffer
- tested on 32bit x86 only, I'll try to do some tests on different platforms as 
  well (on QEMU) but brave people could test it on some real hardware :)
- there are also some addons which could be used by other grub code as well: 
  * suport for adler32 checksum (for lzop)
  * helper functions for easier unaligned access

Last but not least: code is available at [2]. 


Comments and testing are welcome :)


[1] http://www.oberhumer.com/opensource/lzo/#minilzo
[2] http://bzr.savannah.gnu.org/r/grub/people/janc/lzo/

-- 
Szymon K. Janc
address@hidden // GG: 1383435