I have to port the following Java code in Swift.

// Java code
byte [] nodeId = [47, -29, 4, -121]
int numNodeID = 0;
for(int i=0; i < 4; i  ){
   numNodeID |= ((nodeId[i]&0x000000FFL) << (i*8));
}

I wrote

// Swift code
var nodeId: [Int8] = [47, -29, 4, -121]
var numNodeId: Int = 0
for index in 0..<4 {
    numNodeId |= ((Int(nodeId[index]) & 255) << (index*8))
}

The results are different. In Java I obtain the int -2029722833, in swift the int 2265244463. The java result is the signed 2's complement of the swift one.

How can I obtain the signed integer (-2029722833) also in swift?

CodePudding user response：

You're currently thinking that int translates to Int. But no!

On 32-bit platforms, Int is the same size as Int32, and on 64-bit platforms, Int is the same size as Int64.

I can't tell what your code is actually doing, but a direct translation requires Int32 .