bit-count ( obj -- n )
Factor handbook » The language » Numbers » Arithmetic » Bitwise arithmetic » Additional bitwise arithmetic

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Vocabulary
math.bitwise

Inputs

obj

an object

Outputs

n	an integer

Word description
Returns the number of set bits as an object. This word only works on non-negative integers or objects that can be represented as a byte-array.

Examples

USING: math.bitwise prettyprint ; 0xf0 bit-count .
4

USING: math.bitwise prettyprint ; -1 32 bits bit-count .
32

USING: math.bitwise prettyprint ; B{ 1 0 1 } bit-count .
2

Definition

IN: math.bitwise

GENERIC: bit-count ( obj -- n )

Methods

USING: byte-arrays math.bitwise math.bitwise.private ;

M: byte-array bit-count byte-array-bit-count ;


USING: kernel math math.bitwise math.bitwise.private sequences ;

M: integer bit-count
    dup 0 < [ non-negative-integer-expected ] when (bit-count) ;
    inline


USING: alien alien.c-types alien.data kernel math.bitwise
math.bitwise.private ;

M: object bit-count
    binary-object uchar <c-direct-array> byte-array-bit-count ;