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sequences: change to use tuple-hashcode algorithm, make string-hashcode work like old sequence-hashcode.

db4
John Benediktsson 2011-10-05 19:22:50 -07:00
parent 685fc2f86f
commit 7b76c26bc0
3 changed files with 16 additions and 20 deletions
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8
core/sequences/sequences-docs.factor
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@ -1309,13 +1309,7 @@ HELP: sequence-hashcode
{ $values { $values
{ "n" integer } { "seq" sequence } { "n" integer } { "seq" sequence }
{ "x" integer } } { "x" integer } }
{ $description "Iterates over a sequence, computes a hashcode with " { $link hashcode* } " for each element, and combines them using " { $link sequence-hashcode-step } "." } ; { $description "Iterates over a sequence, computes a hashcode with " { $link hashcode* } " for each element, and combines them." } ;
HELP: sequence-hashcode-step
{ $values
{ "oldhash" integer } { "newpart" integer }
{ "newhash" integer } }
{ $description "An implementation word that computes a running hashcode of a sequence using some bit-twiddling. The resulting hashcode is always a fixnum." } ;
HELP: short HELP: short
{ $values { $values

20
core/sequences/sequences.factor
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@ -600,18 +600,14 @@ ERROR: assert-sequence got expected ;
: assert-sequence= ( a b -- ) : assert-sequence= ( a b -- )
2dup sequence= [ 2drop ] [ assert-sequence ] if ; 2dup sequence= [ 2drop ] [ assert-sequence ] if ;
<PRIVATE : sequence-hashcode ( depth seq -- hash )
[
: sequence-hashcode-step ( oldhash newpart -- newhash ) [ drop 1000003 HEX: 345678 ] dip length
>fixnum swap [ [ dup fixnum+fast 82520 fixnum+fast ] [ iota ] bi
[ -2 fixnum-shift-fast ] [ 5 fixnum-shift-fast ] bi ] 2keep [
fixnum+fast fixnum+fast swapd nth-unsafe hashcode* rot fixnum-bitxor
] keep fixnum-bitxor ; inline pick fixnum*fast [ [ fixnum+fast ] keep ] dip swap
] 2curry each drop nip 97531 fixnum+fast ; inline
PRIVATE>
: sequence-hashcode ( n seq -- x )
[ 0 ] 2dip [ hashcode* sequence-hashcode-step ] with each ; inline
M: reversed equal? over reversed? [ sequence= ] [ 2drop f ] if ; M: reversed equal? over reversed? [ sequence= ] [ 2drop f ] if ;

8
core/strings/strings.factor
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@ -13,8 +13,14 @@ IN: strings
: reset-string-hashcode ( str -- ) : reset-string-hashcode ( str -- )
f swap set-string-hashcode ; inline f swap set-string-hashcode ; inline
: string-hashcode-step ( oldhash newpart -- newhash )
>fixnum swap [
[ -2 fixnum-shift-fast ] [ 5 fixnum-shift-fast ] bi
fixnum+fast fixnum+fast
] keep fixnum-bitxor ; inline
: rehash-string ( str -- ) : rehash-string ( str -- )
1 over sequence-hashcode swap set-string-hashcode ; inline [ 0 [ string-hashcode-step ] reduce ] keep set-string-hashcode ; inline
: (aux) ( n string -- byte-array m ) : (aux) ( n string -- byte-array m )
aux>> { byte-array } declare swap 1 fixnum-shift-fast ; inline aux>> { byte-array } declare swap 1 fixnum-shift-fast ; inline