/extra/z-algorithm/z-algorithm.factor
http://github.com/abeaumont/factor · Factor · 38 lines · 28 code · 8 blank · 2 comment · 5 complexity · ce8bb7357b1d69cbfdef67ef66b2b610 MD5 · raw file
- ! Copyright (C) 2010 Dmitry Shubin.
- ! See http://factorcode.org/license.txt for BSD license.
- USING: arrays combinators.smart kernel locals math math.ranges
- sequences sequences.private ;
- IN: z-algorithm
- : lcp ( seq1 seq2 -- n )
- [ min-length ] 2keep mismatch [ nip ] when* ;
- <PRIVATE
- :: out-of-zbox ( seq Z l r k -- seq Z l r )
- seq k tail-slice seq lcp :> Zk
- Zk Z push seq Z
- Zk 0 > [ k Zk k + 1 - ] [ l r ] if ; inline
- :: inside-zbox ( seq Z l r k -- seq Z l r )
- k l - Z nth :> Zk'
- r k - 1 + :> b
- seq Z Zk' b <
- [ Zk' Z push l r ] ! still inside
- [
- seq r 1 + seq b [ tail-slice ] 2bi@ lcp :> q
- q b + Z push k q r +
- ] if ; inline
- : (z-value) ( seq Z l r k -- seq Z l r )
- 2dup < [ out-of-zbox ] [ inside-zbox ] if ; inline
- :: (z-values) ( seq -- Z )
- V{ } clone 0 0 seq length :> ( Z l r len )
- len Z push [ seq Z l r 1 len [a,b) [ (z-value) ] each ]
- drop-outputs Z ; inline
- PRIVATE>
- : z-values ( seq -- Z )
- dup length 0 > [ (z-values) ] when >array ;