fixed-deflate ( bytes -- compressed )

Vocabulary

compression.deflate.private

Inputs

bytes

an object

Outputs

compressed

an object

Definition

USING: arrays kernel math sequences ;

IN: compression.deflate.private

:: fixed-deflate ( bytes -- compressed )
    <deflate-writer> :> writer 3 3 writer write-bits
    65536 f <array> :> positions 0 :> i!
    [ i bytes length < ] [
        0 :> n! 0 :> distance! i 2 + bytes length < [
            i bytes prefix-hash :> hash hash positions nth
            :> previous previous [
                i previous - distance! distance 32768 <=
                [ i previous bytes match-length n! ] when
            ] when
        ] when n 3 >=
        [ n distance writer write-match ]
        [ i bytes nth writer write-literal 1 n! ] if n [| j |
            i j + :> pos pos 2 + bytes length <
            [ pos pos bytes prefix-hash positions set-nth ] when
        ] each-integer i n + i!
    ] while 256 writer write-literal writer finish-bits ;