cuckoo-filters: change language to refer to fingerprints.
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eebdf93e45
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c09cfd586c
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@ -16,7 +16,7 @@ CONSTANT: max-cuckoo-count 500
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! The maximum load factor we allow before growing the capacity
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CONSTANT: max-load-factor 0.96
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! The number of tags to store in each bucket
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! The number of fingerprint to store in each bucket
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CONSTANT: bucket-size 4
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: #buckets ( capacity -- #buckets )
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@ -26,14 +26,14 @@ CONSTANT: bucket-size 4
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: <cuckoo-buckets> ( capacity -- buckets )
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#buckets [ bucket-size f <array> ] replicate ;
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: tag-index ( hash -- tag index )
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: hash-index ( hash -- fingerprint index )
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4 over <displaced-alien> [ uint deref ] bi@ ;
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: alt-index ( tag index -- altindex )
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: alt-index ( fingerprint index -- alt-index )
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[ 0x5bd1e995 w* ] [ bitxor ] bi* ;
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: tag-indices ( bytes cuckoo-filter -- tag i1 i2 )
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checksum>> checksum-bytes tag-index 2dup alt-index ;
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: hash-indices ( bytes cuckoo-filter -- fingerprint index alt-index )
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checksum>> checksum-bytes hash-index 2dup alt-index ;
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: bucket-lookup ( fingerprint bucket -- ? )
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member? ;
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@ -55,41 +55,41 @@ TUPLE: cuckoo-filter buckets checksum size ;
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<cuckoo-buckets> sha1 0 cuckoo-filter boa ;
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:: cuckoo-insert ( bytes cuckoo-filter -- ? )
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bytes cuckoo-filter tag-indices :> ( tag! i1 i2 )
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bytes cuckoo-filter hash-indices :> ( fp! i1 i2 )
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cuckoo-filter buckets>> :> buckets
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buckets length :> n
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{
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[ tag i1 n mod buckets nth bucket-insert ]
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[ tag i2 n mod buckets nth bucket-insert ]
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[ fp i1 n mod buckets nth bucket-insert ]
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[ fp i2 n mod buckets nth bucket-insert ]
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} 0|| [
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cuckoo-filter [ 1 + ] change-size drop t
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] [
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2 random zero? i1 i2 ? :> i!
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max-cuckoo-count [
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drop
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tag i n mod buckets nth bucket-swap tag!
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tag i alt-index i!
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fp i n mod buckets nth bucket-swap fp!
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fp i alt-index i!
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tag i n mod buckets nth bucket-insert
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fp i n mod buckets nth bucket-insert
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dup [ cuckoo-filter [ 1 + ] change-size drop ] when
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] find-integer >boolean
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] if ;
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:: cuckoo-lookup ( bytes cuckoo-filter -- ? )
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bytes cuckoo-filter tag-indices :> ( tag i1 i2 )
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bytes cuckoo-filter hash-indices :> ( fp i1 i2 )
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cuckoo-filter buckets>> :> buckets
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buckets length :> n
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{
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[ tag i1 n mod buckets nth bucket-lookup ]
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[ tag i2 n mod buckets nth bucket-lookup ]
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[ fp i1 n mod buckets nth bucket-lookup ]
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[ fp i2 n mod buckets nth bucket-lookup ]
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} 0|| ;
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:: cuckoo-delete ( bytes cuckoo-filter -- ? )
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bytes cuckoo-filter tag-indices :> ( tag i1 i2 )
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bytes cuckoo-filter hash-indices :> ( fp i1 i2 )
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cuckoo-filter buckets>> :> buckets
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buckets length :> n
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{
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[ tag i1 n mod buckets nth bucket-delete ]
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[ tag i2 n mod buckets nth bucket-delete ]
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[ fp i1 n mod buckets nth bucket-delete ]
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[ fp i2 n mod buckets nth bucket-delete ]
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} 0||
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dup [ cuckoo-filter [ 1 - ] change-size drop ] when ;
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