189 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			Factor
		
	
	
			
		
		
	
	
			189 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			Factor
		
	
	
! Copyright (C) 2007, 2008 Ryan Murphy, Doug Coleman,
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! Slava Pestov.
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! See http://factorcode.org/license.txt for BSD license.
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USING: accessors arrays assocs fry kernel kernel.private locals
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math math.order math.private sequences sequences.private summary
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vectors ;
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IN: heaps
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GENERIC: heap-push* ( value key heap -- entry )
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GENERIC: heap-peek ( heap -- value key )
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GENERIC: heap-pop* ( heap -- )
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GENERIC: heap-pop ( heap -- value key )
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GENERIC: heap-delete ( entry heap -- )
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GENERIC: heap-empty? ( heap -- ? )
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GENERIC: heap-size ( heap -- n )
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<PRIVATE
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TUPLE: heap { data vector } ;
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: <heap> ( class -- heap )
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    V{ } clone swap boa ; inline
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ERROR: not-a-heap object ;
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: check-heap ( heap -- heap )
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    dup heap? [ not-a-heap ] unless ; inline
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TUPLE: entry value key heap index ;
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: <entry> ( value key heap -- entry )
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    f entry boa ; inline
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PRIVATE>
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TUPLE: min-heap < heap ;
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: <min-heap> ( -- min-heap ) min-heap <heap> ;
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TUPLE: max-heap < heap ;
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: <max-heap> ( -- max-heap ) max-heap <heap> ;
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M: heap heap-empty? ( heap -- ? )
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    data>> empty? ; inline
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M: heap heap-size ( heap -- n )
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    data>> length ; inline
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<PRIVATE
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: left ( n -- m )
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    { fixnum } declare 1 fixnum-shift-fast 1 fixnum+fast ; inline
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: right ( n -- m )
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    { fixnum } declare 1 fixnum-shift-fast 2 fixnum+fast ; inline
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: up ( n -- m )
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    { fixnum } declare 1 fixnum-fast 2/ ; inline
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: data-nth ( n heap -- entry )
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    data>> nth-unsafe { entry } declare ; inline
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: data-first ( heap -- entry )
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    data>> first ; inline
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: data-set-nth ( entry n heap -- )
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    [ [ >>index ] keep ] dip data>> set-nth-unsafe ; inline
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: data-push ( entry heap -- n )
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    [ heap-size [ >>index ] keep ]
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    [ data>> [ set-nth ] 2keep drop ] bi ; inline
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GENERIC: heap-compare ( entry1 entry2 heap -- ? )
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M: min-heap heap-compare
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    drop { entry entry } declare [ key>> ] bi@ after? ; inline
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M: max-heap heap-compare
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    drop { entry entry } declare [ key>> ] bi@ before? ; inline
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: data-compare ( m n heap -- ? )
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    [ '[ _ data-nth ] bi@ ] [ heap-compare ] bi ; inline
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PRIVATE>
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: >entry< ( entry -- value key )
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    [ value>> ] [ key>> ] bi ; inline
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M: heap heap-peek ( heap -- value key )
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    data-first >entry< ;
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<PRIVATE
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:: sift-down ( heap from to -- )
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    to heap data-nth :> tmp
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    to t [ over from > and ] [
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        dup up
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        dup heap data-nth
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        dup tmp heap heap-compare [
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            rot heap data-set-nth t
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        ] [
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            2drop f
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        ] if
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    ] while
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    tmp swap heap data-set-nth ; inline
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PRIVATE>
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M: heap heap-push*
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    [ <entry> dup ] [ data-push ] [ 0 rot sift-down ] tri ;
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: heap-push ( value key heap -- )
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    heap-push* drop ;
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: heap-push-all ( assoc heap -- )
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    '[ swap _ heap-push ] assoc-each ;
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<PRIVATE
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:: sift-up ( heap n -- )
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    heap heap-size  :> end
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    n heap data-nth :> tmp
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    n dup left [ dup end < ] [
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        dup 1 fixnum+fast
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        dup end < [ 2dup heap data-compare ] [ f ] if
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        [ nip ] [ drop ] if
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        [ heap data-nth swap heap data-set-nth ]
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        [ dup left ] bi
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    ] while drop
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    tmp over heap data-set-nth
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    heap n rot sift-down ; inline
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PRIVATE>
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M: heap heap-pop*
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    dup data>> dup length 1 > [
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        [ pop ] [ set-first ] bi 0 sift-up
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    ] [
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        pop* drop
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    ] if ; inline
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M: heap heap-pop
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    [ data-first >entry< ] [ heap-pop* ] bi ;
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: slurp-heap ( ... heap quot: ( ... value key -- ... ) -- ... )
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    [ check-heap ] dip
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    [ drop '[ _ heap-empty? ] ]
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    [ '[ _ heap-pop @ ] until ] 2bi ; inline
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: heap-pop-all ( heap -- alist )
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    [ heap-size <vector> ] keep
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    [ swap 2array suffix! ] slurp-heap { } like ;
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ERROR: bad-heap-delete ;
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M: bad-heap-delete summary
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    drop "Invalid entry passed to heap-delete" ;
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<PRIVATE
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: entry>index ( entry heap -- n )
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    over heap>> eq? [ bad-heap-delete ] unless
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    index>> { fixnum } declare ; inline
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PRIVATE>
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M: heap heap-delete
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    [ entry>index ] keep
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    2dup heap-size 1 - = [
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        nip data>> pop*
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    ] [
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        [ nip data>> pop ]
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        [ data-set-nth ]
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        [ swap sift-up ] 2tri
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    ] if ;
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: >min-heap ( assoc -- min-heap )
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    dup assoc-size <vector> min-heap boa
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    [ heap-push-all ] keep ;
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: >max-heap ( assoc -- max-heap )
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    dup assoc-size <vector> max-heap boa
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    [ heap-push-all ] keep ;
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