java - Converting Swift Data into Int16

Question

I have a Java server where I take a short[] and I convert it to a byte[] (Big Endian) and I send it to an iOS device. I am having trouble converting this byte array (or the Data in Swift) into an int16 array ([Int16]). I was also wondering if I was correct in assuming that the Swift equivalent of a Java short type is a Int16 in Swift.

Answer 1

Similarly as in round trip Swift number types to/from Data you can use the withUnsafeBytes method and UnsafeBufferPointer<Int16> to get a view of the data as 16-bit integers. Then use the Int16(bigEndian:) initializer to convert the numbers from big endian to host byteorder. Example:

let data = Data(bytes: [0, 1, 0, 2, 1, 0, 255, 255])
let i16array = data.withUnsafeBytes {
    UnsafeBufferPointer<Int16>(start: $0, count: data.count/2).map(Int16.init(bigEndian:))
}
print(i16array) // [1, 2, 256, -1]

Update for Swift 5:

let data = Data([0, 1, 0, 2, 1, 0, 255, 255])
let i16array = data.withUnsafeBytes {
        Array($0.bindMemory(to: Int16.self)).map(Int16.init(bigEndian:))
    }
print(i16array) // [1, 2, 256, -1]