Zig

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. Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

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

    const sock = try chilkat.Socket.init();
    defer sock.deinit();

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

    const use_tls = false;
    const port = 4242;
    const max_wait_ms = 5000;
    sock.connect("tcpbin.com", port, use_tls, max_wait_ms) catch {
        std.debug.print("{s}\n", .{try sock.getLastErrorText(alloc)});
        return;
    };

    // Wait a max of 2 seconds for a response..
    sock.setMaxReadIdleMs(2000);

    // Send a 16-bit integer using big-endian byte ordering (also called network byte order)
    // 12022 decimal = 2EF6 hex
    var value: i32 = 12022;
    var big_endian: bool = true;
    sock.sendInt16(value, big_endian) catch {};
    // Send it again, because we'll read it two different ways..
    sock.sendInt16(value, big_endian) catch {};

    // The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
    sock.sendByte(10) catch {};

    // 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 hex_str: [:0]const u8 = try sock.receiveNBytesENC(alloc, 2, "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.
    std.debug.print("Expecting big-endian 2EF6\n", .{});
    std.debug.print("{s}\n", .{hex_str});

    // Let's read directly to an integer..
    try sock.receiveInt16(big_endian, true);
    std.debug.print("Expecting 12022\n", .{});
    std.debug.print("Received: {d}\n", .{sock.getReceivedInt()});

    // Consume the LF that gets echoed back..
    sock.receiveByte(true) catch {};

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

    std.debug.print("----\n", .{});

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

    hex_str = try sock.receiveNBytesENC(alloc, 2, "hex");

    std.debug.print("Expecting little-endian F62E\n", .{});
    std.debug.print("{s}\n", .{hex_str});

    try sock.receiveInt16(big_endian, true);
    std.debug.print("Expecting 12022\n", .{});
    std.debug.print("Received: {d}\n", .{sock.getReceivedInt()});

    // Consume the LF that gets echoed back..
    sock.receiveByte(true) catch {};

    sock.close(1000) catch {};

    // Output:

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