method

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v1_8_7_72 - Show latest stable - 0 notes - Class: Fixnum

[](p1) public

Bit Reference—Returns the nth bit in the binary representation of fix, where fix[0] is the least significant bit.

   a = 0b11001100101010
   30.downto(0) do |n| print a[n] end

produces:

   0000000000000000011001100101010

Show source

/*
 *  call-seq:
 *     fix[n]     => 0, 1
 *
 *  Bit Reference---Returns the <em>n</em>th bit in the binary
 *  representation of <i>fix</i>, where <i>fix</i>[0] is the least
 *  significant bit.
 *
 *     a = 0b11001100101010
 *     30.downto(0) do |n| print a[n] end
 *
 *  <em>produces:</em>
 *
 *     0000000000000000011001100101010
 */

static VALUE
fix_aref(fix, idx)
    VALUE fix, idx;
{
    long val = FIX2LONG(fix);
    long i;

    if (!FIXNUM_P(idx = fix_coerce(idx))) {
        idx = rb_big_norm(idx);
        if (!FIXNUM_P(idx)) {
            if (!RBIGNUM(idx)->sign || val >= 0)
                return INT2FIX(0);
            return INT2FIX(1);
        }
    }
    i = FIX2LONG(idx);

    if (i < 0) return INT2FIX(0);
    if (sizeof(VALUE)*CHAR_BIT-1 < i) {
        if (val < 0) return INT2FIX(1);
        return INT2FIX(0);
    }
    if (val & (1L<<i))
        return INT2FIX(1);
    return INT2FIX(0);
}

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