Why is ZLIB_COMPRESSION_OVERHEAD soooo big?

[oliver munz @ s p e a g]

How knows why zlib needs more 3/4 of my RAM per default? What's the minimum 
ZLIB_COMPRESSION_OVERHEAD ?

decompress.c:
78 #ifdef CYGOPT_REDBOOT_FIS_ZLIB_COMMON_BUFFER
79 # define ZLIB_COMPRESSION_OVERHEAD 
CYGNUM_REDBOOT_FIS_ZLIB_COMMON_BUFFER_SIZE
80 #else
81 # define ZLIB_COMPRESSION_OVERHEAD 0xC000
82 #endif

Would zlib work with 0c8000?

Thanks
Oliver Munz