39 lines
1.0 KiB
Factor
39 lines
1.0 KiB
Factor
USING: kernel sequences arrays math vectors ;
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IN: hash2
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! Little ad-hoc datastructure used to map two numbers
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! to a single value.
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! Created for the NFC mapping table.
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! We could use a hashtable of 2arrays, but that
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! involves creating too many objects.
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! Does not allow duplicate keys.
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: hashcode2 ( a b -- hashcode )
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swap 8 shift + ; inline
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: <hash2> ( size -- hash2 ) f <array> ;
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: 2= ( a b pair -- ? )
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first2 swapd >r >r = r> r> = and ; inline
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: (assoc2) ( a b alist -- {a,b,val} )
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[ >r 2dup r> 2= ] find >r 3drop r> ; inline
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: assoc2 ( a b alist -- value )
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(assoc2) dup [ third ] when ; inline
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: set-assoc2 ( value a b alist -- alist )
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>r rot 3array r> ?push ; inline
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: hash2@ ( a b hash2 -- a b bucket hash2 )
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>r 2dup hashcode2 r> [ length mod ] keep ; inline
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: hash2 ( a b hash2 -- value/f )
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hash2@ nth [ assoc2 ] [ 2drop f ] if* ;
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: set-hash2 ( a b value hash2 -- )
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>r -rot r> hash2@ [ set-assoc2 ] change-nth ;
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: alist>hash2 ( alist size -- hash2 )
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<hash2> [ over >r first3 r> set-hash2 ] reduce ; inline
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