(Objective-C) 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.

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#import <CkoSocket.h>
#import <NSString.h>

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

CkoSocket *sock = [[CkoSocket alloc] init];

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

BOOL useTls = NO;
int port = 4242;
int maxWaitMs = 5000;
BOOL success = [sock Connect: @"tcpbin.com" port: [NSNumber numberWithInt: port] ssl: useTls maxWaitMs: [NSNumber numberWithInt: maxWaitMs]];
if (success == NO) {
    NSLog(@"%@",sock.LastErrorText);
    return;
}

// Wait a max of 2 seconds for a response..
sock.MaxReadIdleMs = [NSNumber numberWithInt:2000];

// Send a 16-bit integer using big-endian byte ordering (also called network byte order)
// 12022 decimal = 2EF6 hex
int value = 12022;
BOOL bigEndian = YES;
[sock SendInt16: [NSNumber numberWithInt: value] bigEndian: bigEndian];
// Send it again, because we'll read it two different ways..
[sock SendInt16: [NSNumber numberWithInt: value] bigEndian: bigEndian];

// The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
[sock SendByte: [NSNumber numberWithInt: 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.)
NSString *hexStr = [sock ReceiveNBytesENC: 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.
NSLog(@"%@",@"Expecting big-endian 2EF6");
NSLog(@"%@",hexStr);

// Let's read directly to an integer..
success = [sock ReceiveInt16: bigEndian bUnsigned: YES];
NSLog(@"%@",@"Expecting 12022");
NSLog(@"%@%d",@"Received: ",[sock.ReceivedInt intValue]);

// Consume the LF that gets echoed back..
[sock ReceiveByte: YES];

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

NSLog(@"%@",@"----");

// 12022 decimal = 2EF6 hex, but little-endian byte ordering will send the bytes in the order 0xF6 0x2E
value = 12022;
bigEndian = NO;
[sock SendInt16: [NSNumber numberWithInt: value] bigEndian: bigEndian];
[sock SendInt16: [NSNumber numberWithInt: value] bigEndian: bigEndian];
[sock SendByte: [NSNumber numberWithInt: 10]];

hexStr = [sock ReceiveNBytesENC: 2 encodingAlg: @"hex"];

NSLog(@"%@",@"Expecting little-endian F62E");
NSLog(@"%@",hexStr);

success = [sock ReceiveInt16: bigEndian bUnsigned: YES];
NSLog(@"%@",@"Expecting 12022");
NSLog(@"%@%d",@"Received: ",[sock.ReceivedInt intValue]);

// Consume the LF that gets echoed back..
[sock ReceiveByte: YES];

[sock Close: [NSNumber numberWithInt: 1000]];

// Output:

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