Re: DEFLATE compression

[Bean]

On Mon, Jun 23, 2008 at 9:36 PM, Colin D Bennett <address@hidden> 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).

-- 
Bean