20 lines
540 B
Factor
20 lines
540 B
Factor
! Copyright (C) 2009 Daniel Ehrenberg
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! See http://factorcode.org/license.txt for BSD license.
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USING: sequences kernel math accessors sequences.private ;
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IN: math.bits
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TUPLE: bits { number read-only } { length read-only } ;
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C: <bits> bits
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: make-bits ( number -- bits )
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dup zero? [ drop T{ bits f 0 0 } ] [ dup abs log2 1 + <bits> ] if ; inline
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M: bits length length>> ;
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M: bits nth-unsafe number>> swap bit? ;
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INSTANCE: bits immutable-sequence
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: unbits ( seq -- number )
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<reversed> 0 [ [ 1 shift ] dip [ 1+ ] when ] reduce ;
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