[Zlib-devel] Proposal for a DeflateStateFieldOffset function

[Xavier Le Bris]

Hello,

I have seen in the previous posts that :
'structure inflate_state and deflate_state were modified in zLib 1.2.2.1'

To experiment a "compression level = 10" for png purposes, I tested with 
zlib.dll some modifications of the fields MatchLen, MaxChainLen, GoodMatch, 
NiceMatch, etc...

I know that it is an internal structure and it is forbidden to access these 
variables.
But, I saw also that it is a hard and risky stuff to modify the asm version 
for Gilles Vollant (in match.s)
Could it be possible either to stop modify this structure (additions at the 
end) or, better, to retrieve the offset of each field in the deflate_state 
structure by a function.

Example (sorry for the pascal syntax) :

function DeflateStateFieldOffset(S : string) : longint;
begin
       if (S = 'matchlen') then Result := 116 else
       if (S = 'goodmatch') then Result := 132 else
      ...
end;

Obviously 116, 132 must be calculate automatically.

Regards

Xavier