Re: DEFLATE compression

["Vesa Jääskeläinen" <chaac@nic.fi>]

Bean wrote:
> On Mon, Jun 23, 2008 at 9:36 PM, Colin D Bennett <colin@gibibit.com> wrote:
>> How does GRUB support decompressing DEFLATE compressed data?  Based on
>> my reading of io/gzio.c, it looks like a gzip header is required to
>> inflate deflated data.
>>
>> I am implementing a new font format and will be embedding multiple
>> blocks of compressed bitmaps in the font file for a good combination of
>> space efficient on-disk storage and fast read performance during use.
>> A block of character bitmaps will only be read from the file
>> and decompressed at run time when a character within that block is
>> needed. After that, when any character in the block is needed, it is
>> already decompressed in memory for quick access.
>>
>> I was going to use DEFLATE compression, it looks like I may have to add
>> the gzip structure to it, which seems silly since it's just a block of
>> data within my file.
>>
>> Also, is it possible to tell the gzio module to decompress a block of
>> data beginning at a specific offset in the file?
> 
> Hi,
> 
> I think it's better to move the deflate decompression function into a
> separate module, instead of relying on gzio. I have written similar
> deflate function for pnp.c, but it uses callback mode, which call a
> function to retrieve the next character. It'd be nice to unify all
> deflate decompression in one module, but you need to be careful about
> the interface, so that it can be used in both situation (direct and
> callback mode).

Hi Bean,

Can you check the interface as you have previously worked with it? This 
would free Colin to work on more important aspects.

Thanks,
Vesa Jääskeläinen