src/message.zig

@@ -31,11 +31,27 @@ pub const Error = error{
 // ZERO COPY STUFF
 // &payload could be a void value that is treated as a pointer to a [*]u8
 pub const ZeroCopyMessage = packed struct {
-    pub const Relay = packed struct {
+    const Relay = packed struct {
         dest: @Vector(4, u8),
         payload: void,
+
+        pub fn getPayload(self: *align(1) Relay) []u8 {
+            // const vself: *void = @ptrCast(self);
+            // var parent: *align(1) ZeroCopyMessage = @fieldParentPtr("bytes", vself);
+            // if (false) {
+            //     parent = @ptrFromInt(@intFromPtr(parent));
+            // }
+            const len: *u16 = @ptrFromInt(@intFromPtr(self) - @sizeOf(u16));
+            // std.debug.print("relay: {*}\n", .{self});
+            // std.debug.print("inPayload: {*}\n", .{parent});
+            // std.debug.print("len: {d}\n", .{len.*});
+            // std.debug.print("len: {d}\n", .{parent.length});
+            // return @as([*]u8, @ptrCast(&self.payload))[0..3];
+            // return @as([*]u8, @ptrCast(&self.payload))[0 .. parent.length - @sizeOf(Relay)];
+            return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @sizeOf(Relay)];
+        }
     };
-    pub const Connection = packed struct {
+    const Connection = packed struct {
         src_port: u16, // random number > 1024
         dest_port: u16, // random number > 1024
         seq_num: u32 = 0,
@@ -43,6 +59,11 @@ pub const ZeroCopyMessage = packed struct {
         reserved: u8 = 0,
         options: ConnectionOptions = .{},
         payload: void,
+
+        pub fn getPayload(self: *align(1) Connection) []u8 {
+            const len: *u16 = @ptrFromInt(@intFromPtr(self) - @sizeOf(u16));
+            return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @sizeOf(Connection)];
+        }
     };
 
     const Self = @This();
@@ -70,6 +91,9 @@ pub const ZeroCopyMessage = packed struct {
             else => Error.UnknownSaprusType,
         };
     }
+
+    pub fn toNativeBytes() void {}
+    pub fn toNetworkBytes() void {}
 };
 
 test "testing variable length zero copy struct" {
@@ -80,9 +104,11 @@ test "testing variable length zero copy struct" {
     const zcm: *align(1) ZeroCopyMessage = @ptrCast(bytes.ptr);
 
     zcm.type = .relay;
-    zcm.length = 3;
+    zcm.length = 64;
-    std.debug.print("{any}\n", .{zcm});
+    std.debug.print("pre: {*}\n", .{zcm});
-    std.debug.print("{any}\n", .{(try zcm.getSaprusTypePayload()).relay});
+    // std.debug.print("{any}\n", .{(try zcm.getSaprusTypePayload()).relay});
+    std.debug.print("{x}\n", .{(try zcm.getSaprusTypePayload()).relay.getPayload()});
+    std.debug.print("{d}\n", .{(try zcm.getSaprusTypePayload()).relay.getPayload().len});
     if (false) {
         // Illegal behavior
         std.debug.print("{any}\n", .{(try zcm.getSaprusTypePayload()).connection});