wyhash

Vocabulary

checksums.wyhash

Definition

IN: checksums.wyhash

TUPLE: wyhash seed ;

Methods

USING: accessors alien.c-types checksums checksums.wyhash
checksums.wyhash.private endian grouping kernel math sequences
sequences.generalizations sequences.private ;

M:: wyhash checksum-bytes ( bytes checksum -- value )
    checksum seed>> P0 bitxor
    :> seed! bytes length :> len len 16 <= [
        len 8 <= [
            len 4 >= [
                bytes [ 4 head-slice ] [ 4 tail-slice* ] bi
                [ le> ] bi@
            ] [
                len 0 > [
                    0 bytes nth 16 shift len 2/ bytes nth
                    8 shift bitor len 1 - bytes nth bitor 0
                ] [ 0 0 ] if
            ] if
        ] [
            bytes [ 8 head-slice ] [ 8 tail-slice* ] bi
            [ le> ] bi@
        ] if
    ] [
        len 1 - dup 48 mod - :> len/48 len 1 - dup 16 mod -
        :> len/16 0 len/48 bytes uint64_t native-mapper [
            seed :> see1! seed :> see2! 6 <groups> [
                6 firstn-unsafe :> ( n0 n1 n2 n3 n4 n5 ) n0 P1
                bitxor n1 seed bitxor wymix seed! n2 P2 bitxor
                n3 see1 bitxor wymix see1! n4 P3 bitxor
                n5 see2 bitxor wymix see2!
            ] each see1 see2 bitxor seed bitxor seed!
        ] unless-empty
        len/48 len/16 bytes uint64_t native-mapper [
            2 <groups> [
                first2-unsafe :> ( n0 n1 ) n0 P1 bitxor
                n1 seed bitxor wymix seed!
            ] each
        ] unless-empty len 16 - len bytes uint64_t native-mapper
        first2
    ] if :> ( a b ) len P1 bitxor a P1 bitxor b seed bitxor
    wymix wymix ;