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game-of-life: simpler wraparound logic in count-neighbors.

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John Benediktsson 2018-03-14 15:44:30 -07:00
parent 0e88bd305e
commit c5a7ce216b
1 changed files with 4 additions and 7 deletions
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extra/game-of-life/game-of-life.factor
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@ -22,26 +22,23 @@ IN: game-of-life
bit-array boa bit-array boa
] map! drop ; ] map! drop ;
:: wraparound ( x min max -- y )
x min < [ max ] [ x max > min x ? ] if ; inline
:: count-neighbors ( grid -- counts ) :: count-neighbors ( grid -- counts )
grid grid-dim { fixnum fixnum } declare :> ( rows cols ) grid grid-dim { fixnum fixnum } declare :> ( rows cols )
rows 1 - { fixnum } declare :> max-rows rows 1 - { fixnum } declare :> max-rows
cols 1 - { fixnum } declare :> max-cols cols 1 - { fixnum } declare :> max-cols
rows [ cols <byte-array> ] replicate :> neighbors rows [ cols <byte-array> ] replicate :> neighbors
grid { array } declare [| row j | grid { array } declare [| row j |
j 1 - 0 max-rows wraparound j 0 eq? [ max-rows ] [ j 1 - ] if
j j
j 1 + 0 max-rows wraparound j max-rows eq? [ 0 ] [ j 1 + ] if
[ neighbors nth-unsafe { byte-array } declare ] tri@ :> [ neighbors nth-unsafe { byte-array } declare ] tri@ :>
( above same below ) ( above same below )
row { bit-array } declare [| cell i | row { bit-array } declare [| cell i |
cell [ cell [
i 1 - 0 max-cols wraparound i 0 eq? [ max-cols ] [ i 1 - ] if
i i
i 1 + 0 max-cols wraparound i max-cols eq? [ 0 ] [ i 1 + ] if
[ [ above [ 1 + ] change-nth-unsafe ] tri@ ] [ [ above [ 1 + ] change-nth-unsafe ] tri@ ]
[ nip [ same [ 1 + ] change-nth-unsafe ] bi@ ] [ nip [ same [ 1 + ] change-nth-unsafe ] bi@ ]