CODEWITHSUNDEEP
swiftoption-type
Joyal Clifford
Joyal Clifford

Reputation: 1212

Optional UInt8? gives 2 byte memory size

UInt8 memory size is 1 byte . but when i make it optional value, it gives 2 byte of size. 

   var serail : UInt8? = 255
    print(MemoryLayout.size(ofValue: serail)) // it gives 2 byte size.


        var serail : UInt8 = 255
        print(MemoryLayout.size(ofValue: serail)) // it gives 1 byte size.

how to get exactly 1 byte memory size for Integer value

Upvotes: 3

Views: 408

Answers (1)

tktsubota
tktsubota

Reputation: 9391

Under the hood, an optional is an enum and looks something like this:

enum Optional<Wrapped> {
    case some(Wrapped)  // not nil
    case none  // nil
}

The symbols ? and ! are just shorthands for referring to this optional enum. This extra layer causes it to be 2 bytes large.

However, if you unwrap the optional, the returned value is the wrapped value itself, so it becomes 1 byte.

Upvotes: 1

Related Questions