1 ! Copyright (C) 2009 Daniel Ehrenberg
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: sequences kernel math accessors sequences.private ;
6 TUPLE: bits { number read-only } { length read-only } ;
9 : check-negative-bits ( n -- n )
10 dup 0 < [ non-negative-integer-expected ] when ; inline
12 : make-bits ( number -- bits )
14 [ T{ bits f 0 1 } ] [ dup abs log2 1 + <bits> ] if-zero ; inline
16 M: bits length length>> ; inline
18 M: bits nth-unsafe number>> swap bit? ; inline
20 INSTANCE: bits immutable-sequence
22 : bits>number ( seq -- number )
23 <reversed> 0 [ [ 1 shift ] dip [ 1 + ] when ] reduce ;