city-murmur ( bytes low high -- hash )

Vocabulary

checksums.cityhash.private

Inputs

bytes	an object
low	an object
high	an object

Outputs

hash

an object

Definition

USING: kernel math math.bitwise sequences ;

IN: checksums.cityhash.private

:: city-murmur ( bytes low high -- hash )
    bytes length :> len low :> a! high :> b! 0 :> c! 0 :> d! len
    16 <= [
        a k1 W* shift-mix k1 W* a! b k1 W* bytes hash64-0to16 W+
        c! a len 8 >= [ bytes 0 fetch64 ] [ c ] if W+
        shift-mix d!
    ] [
        bytes len 8 - fetch64 k1 W+ a hash16 c! b len W+
        c bytes len 16 - fetch64 W+ hash16 d! a d W+ a! len 1 -
        16 /i <iota> [| i |
            a bytes i 16 * fetch64 k1 W* shift-mix k1 W* bitxor
            k1 W* a! b a bitxor b! c bytes i 16 * 8 + fetch64
            k1 W* shift-mix k1 W* bitxor k1 W* c! d c bitxor d!
        ] each
    ] if a c hash16 a! d b hash16 b! a b bitxor b a hash16
    >uint128 ;