hash64-0to16 ( bytes -- hash )

Vocabulary

checksums.cityhash.private

Inputs

bytes

an object

Outputs

hash

an object

Definition

USING: combinators math math.bitwise sequences ;

IN: checksums.cityhash.private

:: hash64-0to16 ( bytes -- hash )
    bytes length :> len k2 len 2 * W+ :> mul {
        {
            [ len 8 >= ]
            [
                bytes 0 fetch64 k2 W+ :> a bytes len 8 - fetch64
                :> b b -37 bitroll-64 mul W* a W+
                a -25 bitroll-64 b W+ mul W* mul hash16-mul
            ]
        }
        {
            [ len 4 >= ]
            [
                bytes 0 fetch32 3 shift len W+ bytes len 4 -
                fetch32 mul hash16-mul
            ]
        }
        {
            [ len 0 > ]
            [
                bytes first len -1 shift bytes nth 8 shift +
                k2 W* len bytes last 2 shift + k0 W* bitxor
                shift-mix k2 W*
            ]
        }
        [ k2 ]
    } cond ;