[Zlib-devel] Plans for zlib 1.2.5

[Török Edwin]

On 02/22/2010 02:40 PM, Mark Adler wrote:
> Edwin,
> 
> On Feb 22, 2010, at 1:09 AM, Török Edwin wrote:
>> I noticed that Z_FILTERED gives a significant improvement in compression
>> ratio (around 9%) when used on text files which contain lot of
>> hexadecimal-encoded data; for example ClamAV's database, which uses
>> Z_FILTERED now for compression.
>>
>> Could zlib automatically determine what is best for a block, and use the
>> strategy that gives best compression ratio?
> 
> Yes, it could.  I'll put that on the list.
> 

Thanks. Will that be a new flag for gzopen?

>> Is there anything else that
>> could be tuned by introducing new strategies that are transparent to the
>> decompressor?
> 
> Yes, there are ways to make compression better by about 2% to 10% with a much slower but more aggressive deflator.  I will consider that for a version after 1.2.5.

Sound good!
FWIW XZ only gives 2.7% better compression than zlib (in my particular
case), and is 9x slower.

Best regards,
--Edwin