From c391b4da5555cb2b19f17e6479ec83c15d337ea3 Mon Sep 17 00:00:00 2001
From: Robby Zambito <contact@robbyzambito.me>
Date: Wed, 2 Apr 2025 22:36:33 -0400
Subject: Working with nice union
This let's us easily use a single type for all Saprus messages, and unwrap the specific type with a switch.
---
src/main.zig | 80 +++++++++++++++++++-----------------------------------------
1 file changed, 25 insertions(+), 55 deletions(-)
diff --git a/src/main.zig b/src/main.zig
index f0c1731..e7df07d 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -9,33 +9,30 @@ const SaprusPacketType = enum(u16) {
file_transfer = 0x8888,
};
-const SaprusHeaderFrame = struct {
- msg_type: SaprusPacketType,
- payload: []u8,
+const SaprusMessage = union(SaprusPacketType) {
+ relay: struct {
+ dest: [4]u8,
+ payload: []u8,
+ },
+ file_transfer: void, // unimplemented
const Self = @This();
fn toBytes(s: Self, allocator: Allocator) ![]u8 {
- const buf = try allocator.alloc(u8, 4 + s.payload.len);
- std.mem.writeInt(u16, buf[0..2], @intFromEnum(s.msg_type), .big);
- std.mem.writeInt(u16, buf[2..4], @intCast(s.payload.len), .big);
- std.mem.copyForwards(u8, buf[4..], s.payload);
- return buf;
- }
-};
-
-const SaprusRelayMessage = struct {
- dest: [4]u8,
- payload: []u8,
-
- const Self = @This();
+ var buf = std.ArrayList(u8).init(allocator);
+ const w = buf.writer();
+ try w.writeInt(u16, @intFromEnum(@as(SaprusPacketType, s)), .big);
+
+ switch (s) {
+ .relay => |relay| {
+ try w.writeAll(&relay.dest);
+ try w.writeInt(u16, @intCast(relay.payload.len), .big);
+ try w.writeAll(relay.payload);
+ },
+ .file_transfer => unreachable,
+ }
- fn toBytes(s: Self, allocator: Allocator) ![]u8 {
- const buf = try allocator.alloc(u8, 4 + s.payload.len);
- std.mem.copyForwards(u8, buf[0..4], &s.dest);
- std.mem.copyForwards(u8, buf[4..], s.payload);
- std.debug.print("in tobytes {x}\n", .{buf});
- return buf;
+ return buf.toOwnedSlice();
}
};
@@ -48,22 +45,13 @@ pub fn main() !void {
var allocator = if (dba) |*d| d.allocator() else std.heap.smp_allocator;
- const str_msg = "Hello darkness my old friend";
- var payload_bytes: [str_msg.len + 1]u8 = @splat(0);
- // const payload_bytes = try allocator.alloc(u8, str_msg.len);
- // defer allocator.free(payload_bytes);
- // std.mem.copyForwards(u8, payload_bytes[0..], str_msg);
- std.mem.copyBackwards(u8, payload_bytes[0..], str_msg);
- const relay: SaprusRelayMessage = .{
- .dest = [_]u8{ 255, 255, 255, 255 },
- .payload = payload_bytes[0..str_msg.len],
- };
- const relay_bytes = try relay.toBytes(allocator);
- defer allocator.free(relay_bytes);
- const msg: SaprusHeaderFrame = .{
- .msg_type = .relay,
- .payload = relay_bytes,
+ const msg = SaprusMessage{
+ .relay = .{
+ .dest = .{ 255, 255, 255, 255 },
+ .payload = @ptrCast(@constCast("Hello darkness my old friend")),
+ },
};
+
const msg_bytes = try msg.toBytes(allocator);
defer allocator.free(msg_bytes);
@@ -88,25 +76,7 @@ pub fn main() !void {
try sock.bind(bind_addr);
- // std.debug.print("relay: {x}\n", .{relay_bytes});
- std.debug.print("message bytes: {x}\n", .{msg_bytes});
-
- // @breakpoint();
_ = try sock.sendTo(dest_addr, msg_bytes);
-
- // // Prints to stderr (it's a shortcut based on `std.io.getStdErr()`)
- // std.debug.print("All your {any} are belong to us.\n", .{msg});
-
- // // stdout is for the actual output of your application, for example if you
- // // are implementing gzip, then only the compressed bytes should be sent to
- // // stdout, not any debugging messages.
- // const stdout_file = std.io.getStdOut().writer();
- // var bw = std.io.bufferedWriter(stdout_file);
- // const stdout = bw.writer();
-
- // try stdout.print("Run `zig build test` to run the tests.\n", .{});
-
- // try bw.flush(); // Don't forget to flush!
}
test "simple test" {
--
cgit