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, and stores the result in the left-hand-side variable.
Required. Default implementation provided.
SDK
- Xcode 9.0+
Framework
- Swift Standard Library
Declaration
static func &<<= (lhs: inout Self, rhs: Self)
Parameters
lhsThe value to shift.
rhsThe number of bits to shift
lhsto the left. Ifrhsis outside the range0..<lhs, it is masked to produce a value within that range..bit Width
Discussion
The &<<= operator performs a masking shift, where the value used as rhs is masked to produce a value in the range 0..<lhs. 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.
var x: UInt8 = 30 // 0b00011110
x &<<= 2
// x == 120 // 0b01111000
However, if you pass 19 as rhs, the method first bitmasks rhs to 3, and then uses that masked value as the number of bits to shift lhs.
var y: UInt8 = 30 // 0b00011110
y &<<= 19
// y == 240 // 0b11110000