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cuckoo-filters: change language to refer to fingerprints.

char-rename
John Benediktsson 2016-08-08 17:01:53 -07:00
parent eebdf93e45
commit c09cfd586c
1 changed files with 17 additions and 17 deletions
extra/cuckoo-filters

34
extra/cuckoo-filters/cuckoo-filters.factor
View File

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