2 package IO::Compress::Zlib::Constants ;
10 our ($VERSION, @ISA, @EXPORT);
29 ZLIB_FLG_FCHECK_OFFSET
38 ZLIB_FLG_LEVEL_FASTEST
40 ZLIB_FLG_LEVEL_DEFAULT
41 ZLIB_FLG_LEVEL_SLOWEST
47 # Constant names derived from RFC1950
49 use constant ZLIB_HEADER_SIZE => 2;
50 use constant ZLIB_TRAILER_SIZE => 4;
52 use constant ZLIB_CMF_CM_OFFSET => 0;
53 use constant ZLIB_CMF_CM_BITS => 0xF ; # 0b1111
54 use constant ZLIB_CMF_CM_DEFLATED => 8;
56 use constant ZLIB_CMF_CINFO_OFFSET => 4;
57 use constant ZLIB_CMF_CINFO_BITS => 0xF ; # 0b1111;
58 use constant ZLIB_CMF_CINFO_MAX => 7;
60 use constant ZLIB_FLG_FCHECK_OFFSET => 0;
61 use constant ZLIB_FLG_FCHECK_BITS => 0x1F ; # 0b11111;
63 use constant ZLIB_FLG_FDICT_OFFSET => 5;
64 use constant ZLIB_FLG_FDICT_BITS => 0x1 ; # 0b1;
66 use constant ZLIB_FLG_LEVEL_OFFSET => 6;
67 use constant ZLIB_FLG_LEVEL_BITS => 0x3 ; # 0b11;
69 use constant ZLIB_FLG_LEVEL_FASTEST => 0;
70 use constant ZLIB_FLG_LEVEL_FAST => 1;
71 use constant ZLIB_FLG_LEVEL_DEFAULT => 2;
72 use constant ZLIB_FLG_LEVEL_SLOWEST => 3;
74 use constant ZLIB_FDICT_SIZE => 4;