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sequences.rotated: can be a lot faster if we don't circular-wrap.

db4
John Benediktsson 2015-05-11 19:41:01 -07:00
parent 1f2ecfde76
commit 5ea4e26bc5
1 changed files with 11 additions and 7 deletions
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18
extra/sequences/rotated/rotated.factor
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@ -1,20 +1,24 @@
! Copyright (C) 2012 John Benediktsson ! Copyright (C) 2012 John Benediktsson
! See http://factorcode.org/license.txt for BSD license ! See http://factorcode.org/license.txt for BSD license
USING: accessors circular kernel math sequences ; USING: accessors kernel math sequences ;
IN: sequences.rotated IN: sequences.rotated
TUPLE: rotated TUPLE: rotated
{ circular circular read-only } { seq read-only }
{ n integer read-only } ; { n integer read-only } ;
: <rotated> ( seq n -- rotated ) C: <rotated> rotated
[ <circular> ] dip rotated boa ;
M: rotated length circular>> length ; M: rotated length seq>> length ;
M: rotated virtual@ [ n>> + ] [ circular>> ] bi ; M: rotated virtual@
[ n>> + ] [ seq>> ] bi [
length over 0 < [ + ] [
2dup >= [ - ] [ drop ] if
] if
] keep ;
M: rotated virtual-exemplar circular>> ; M: rotated virtual-exemplar seq>> ;
INSTANCE: rotated virtual-sequence INSTANCE: rotated virtual-sequence