/extra/boyer-moore/boyer-moore.factor
http://github.com/abeaumont/factor · Factor · 79 lines · 56 code · 21 blank · 2 comment · 13 complexity · daa4fb458671f8dbb219bb79856a651b MD5 · raw file
- ! Copyright (C) 2010 Dmitry Shubin.
- ! See http://factorcode.org/license.txt for BSD license.
- USING: accessors arrays assocs kernel locals math math.order
- math.ranges sequences sequences.private z-algorithm ;
- FROM: sequences.private => change-nth-unsafe ;
- IN: boyer-moore
- <PRIVATE
- :: (normal-suffixes) ( i zs ss -- )
- i zs nth-unsafe ss
- [ [ i ] unless* ] change-nth-unsafe ; inline
- : normal-suffixes ( zs -- ss )
- [ length [ f <array> ] [ [1,b) ] bi ] keep pick
- [ (normal-suffixes) ] 2curry each ; inline
- :: (partial-suffixes) ( len old elt i -- len old/new old )
- len elt i 1 + = [ len elt - ] [ old ] if old ; inline
- : partial-suffixes ( zs -- ss )
- [ length dup ] [ <reversed> ] bi
- [ (partial-suffixes) ] map-index 2nip ; inline
- : <gs-table> ( seq -- table )
- z-values [ partial-suffixes ] [ normal-suffixes ] bi
- [ [ nip ] when* ] 2map reverse! ; inline
- : insert-bc-shift ( table elt len i -- table )
- 1 + swap - swap pick 2dup key?
- [ 3drop ] [ set-at ] if ; inline
- : <bc-table> ( seq -- table )
- H{ } clone swap [ length ] keep
- [ insert-bc-shift ] with each-index ; inline
- TUPLE: boyer-moore pattern bc-table gs-table ;
- : gs-shift ( i c bm -- s ) nip gs-table>> nth-unsafe ; inline
- : bc-shift ( i c bm -- s ) bc-table>> at dup 1 ? + ; inline
- : do-shift ( pos i c bm -- newpos )
- [ gs-shift ] [ bc-shift ] bi-curry 2bi max + ; inline
- : match? ( i1 s1 i2 s2 -- ? ) [ nth-unsafe ] 2bi@ = ; inline
- :: mismatch? ( s1 s2 pos len -- i/f )
- len 1 - [ [ pos + s1 ] keep s2 match? not ]
- find-last-integer ; inline
- :: (search-from) ( seq from bm -- i/f )
- bm pattern>> :> pat
- pat length :> plen
- seq length plen - :> lim
- from
- [
- dup lim <=
- [
- seq pat pick plen mismatch?
- [ 2dup + seq nth-unsafe bm do-shift t ] [ f ] if*
- ] [ drop f f ] if
- ] loop ; inline
- PRIVATE>
- : <boyer-moore> ( pat -- bm )
- dup <reversed> [ <bc-table> ] [ <gs-table> ] bi
- boyer-moore boa ;
- GENERIC: search-from ( seq from obj -- i/f )
- M: sequence search-from
- dup length zero?
- [ 3drop 0 ] [ <boyer-moore> (search-from) ] if ;
- M: boyer-moore search-from (search-from) ;
- : search ( seq obj -- i/f ) [ 0 ] dip search-from ;