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<DIV><SPAN class=614331821-15062003><FONT face=Arial size=2>unzip 5.5 introduced
support of Deflate64 compression format</FONT></SPAN></DIV>
<DIV><SPAN class=614331821-15062003><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=614331821-15062003><FONT face=Arial size=2>Just for info,
inflate.c of unzip 5.5 say</FONT></SPAN></DIV>
<DIV><SPAN class=614331821-15062003><FONT face=Arial size=2>The Deflate64 (PKZIP
method 9) variant of the compression algorithm<BR>differs from "classic" deflate
in the following 3 aspect:<BR>a) The size of the sliding history window is
expanded to 64 kByte.<BR>b) The previously unused distance codes #30 and #31
code distances<BR> from 32769 to 49152 and 49153 to 65536.
Both codes take 14 bits<BR> of extra data to determine the exact
position in their 16 kByte<BR> range.<BR>c) The last lit/length code
#285 gets a different meaning. Instead<BR> of coding a fixed maximum
match length of 258, it is used as a<BR> "generic" match length
code, capable of coding any length from<BR> 3 (min match length + 0)
to 65538 (min match length + 65535).<BR> This means that the length
code #285 takes 16 bits (!) of uncoded<BR> extra data, added to a
fixed min length of 3.<BR>Changes a) and b) would have been transparent for
valid deflated<BR>data, but change c) requires to switch decoder configurations
between<BR>Deflate and Deflate64 modes.</FONT></SPAN></DIV>
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size=2></FONT></SPAN> </DIV>
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size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=614331821-15062003><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=614331821-15062003><FONT face=Arial size=2>Do you known if we
can imagine a zLib that support Deflate64 stream ?</FONT></SPAN></DIV>
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