Swift

Socket Send/Receive 16-bit Integers

Demonstrates sending and receiving 16-bit integers over a socket connection using either big-endian or little-endian byte ordering. Swift

func chilkatTest() {
    var success: Bool = false

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    let sock = CkoSocket()!

    // --------------------------------------------------------------------
    // This example uses the public TCP echo service at https://tcpbin.com/
    // --------------------------------------------------------------------

    var useTls: Bool = false
    var port: Int = 4242
    var maxWaitMs: Int = 5000
    success = sock.connect(hostname: "tcpbin.com", port: port, ssl: useTls, maxWaitMs: maxWaitMs)
    if success == false {
        print("\(sock.lastErrorText!)")
        return
    }

    // Wait a max of 2 seconds for a response..
    sock.maxReadIdleMs = 2000

    // Send a 16-bit integer using big-endian byte ordering (also called network byte order)
    // 12022 decimal = 2EF6 hex
    var value: Int = 12022
    var bigEndian: Bool = true
    sock.sendInt16(value: value, bigEndian: bigEndian)
    // Send it again, because we'll read it two different ways..
    sock.sendInt16(value: value, bigEndian: bigEndian)

    // The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
    sock.sendByte(value: 10)

    // Let's see hex values of the 2 bytes sent in network byte order (big-endian)
    // (The echo server sends back exactly the bytes received.)
    var hexStr: String? = sock.receiveNBytesENC(numBytes: 2, encodingAlg: "hex")

    // In the big-ending byte order, the byte order is most significant byte to least significant,
    // therefore we should see the bytes in the order 0x2E 0xF6.
    print("Expecting big-endian 2EF6")
    print("\(hexStr!)")

    // Let's read directly to an integer..
    success = sock.receiveInt16(bigEndian: bigEndian, bUnsigned: true)
    print("Expecting 12022")
    print("Received: \(sock.receivedInt.intValue)")

    // Consume the LF that gets echoed back..
    sock.receiveByte(bUnsigned: true)

    // --------------------------------------------------------------------
    // Let's do the same thing, but with little-endian byte ordering.

    print("----")

    // 12022 decimal = 2EF6 hex, but little-endian byte ordering will send the bytes in the order 0xF6 0x2E
    value = 12022
    bigEndian = false
    sock.sendInt16(value: value, bigEndian: bigEndian)
    sock.sendInt16(value: value, bigEndian: bigEndian)
    sock.sendByte(value: 10)

    hexStr = sock.receiveNBytesENC(numBytes: 2, encodingAlg: "hex")

    print("Expecting little-endian F62E")
    print("\(hexStr!)")

    success = sock.receiveInt16(bigEndian: bigEndian, bUnsigned: true)
    print("Expecting 12022")
    print("Received: \(sock.receivedInt.intValue)")

    // Consume the LF that gets echoed back..
    sock.receiveByte(bUnsigned: true)

    sock.close(maxWaitMs: 1000)

    // Output:

    // Expecting big-endian 2EF6
    // 2EF6
    // Expecting 12022
    // Received: 12022
    // ----
    // Expecting little-endian F62E
    // F62E
    // Expecting 12022
    // Received: 12022

}