sqids-shuffle ( alphabet -- alphabet' )

Vocabulary

sqids.private

Inputs

alphabet

an object

Outputs

alphabet'

an object

Definition

USING: kernel math sequences ;

IN: sqids.private

:: sqids-shuffle ( alphabet -- alphabet' )
    alphabet clone :> chars chars length :> len len 1 - <iota> 
    [| i |
        len 1 - i - :> j i j * i chars nth + j chars nth +
        len mod :> r i r chars exchange
    ] each chars ;