&<<(_:_:)
Returns the result of shifting a value’s binary representation the specified number of digits to the left, masking the shift amount to the type’s bit width.
Available because
Self
conforms toFixedWidthInteger
.
static func &<< <Other>(lhs: Self, rhs: Other) -> Self where Other : BinaryInteger
Parameters
- lhs
The value to shift.
- rhs
The number of bits to shift
lhs
to the left. Ifrhs
is outside the range0..<lhs.bitWidth
, it is masked to produce a value within that range.
Overview
Use the masking left shift operator (&<<
) when you need to perform a shift and are sure that the shift amount is in the range 0..<lhs.bitWidth
. Before shifting, the masking left shift operator masks the shift to this range. The shift is performed using this masked value.
The following example defines x
as an instance of UInt8
, an 8-bit, unsigned integer type. If you use 2
as the right-hand-side value in an operation on x
, the shift amount requires no masking.
let x: UInt8 = 30 // 0b00011110
let y = x &<< 2
// y == 120 // 0b01111000
However, if you use 8
as the shift amount, the method first masks the shift amount to zero, and then performs the shift, resulting in no change to the original value.
let z = x &<< 8
// z == 30 // 0b00011110
If the bit width of the shifted integer type is a power of two, masking is performed using a bitmask; otherwise, masking is performed using a modulo operation.