src/message.zig

@@ -26,6 +26,7 @@ pub const ConnectionOptions = packed struct(u8) {
 pub const Error = error{
     NotImplementedSaprusType,
     UnknownSaprusType,
+    InvalidMessage,
 };
 
 // ZERO COPY STUFF
@@ -35,19 +36,10 @@ pub const ZeroCopyMessage = 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 RSelf = *align(1) @This();
+
+        pub fn getPayload(self: RSelf) []u8 {
             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)];
         }
     };
@@ -60,10 +52,26 @@ pub const ZeroCopyMessage = packed struct {
         options: ConnectionOptions = .{},
         payload: void,
 
-        pub fn getPayload(self: *align(1) Connection) []u8 {
+        const CSelf = *align(1) Connection;
+
+        pub fn getPayload(self: CSelf) []u8 {
             const len: *u16 = @ptrFromInt(@intFromPtr(self) - @sizeOf(u16));
             return @as([*]u8, @ptrCast(&self.payload))[0 .. len.* - @sizeOf(Connection)];
         }
+
+        fn nativeFromNetworkEndian(self: CSelf) Error!void {
+            self.src_port = bigToNative(@TypeOf(self.src_port), self.src_port);
+            self.dest_port = bigToNative(@TypeOf(self.dest_port), self.dest_port);
+            self.seq_num = bigToNative(@TypeOf(self.seq_num), self.seq_num);
+            self.msg_id = bigToNative(@TypeOf(self.msg_id), self.msg_id);
+        }
+
+        fn networkFromNativeEndian(self: CSelf) Error!void {
+            self.src_port = nativeToBig(@TypeOf(self.src_port), self.src_port);
+            self.dest_port = nativeToBig(@TypeOf(self.dest_port), self.dest_port);
+            self.seq_num = nativeToBig(@TypeOf(self.seq_num), self.seq_num);
+            self.msg_id = nativeToBig(@TypeOf(self.msg_id), self.msg_id);
+        }
     };
 
     const Self = @This();
@@ -72,14 +80,14 @@ pub const ZeroCopyMessage = packed struct {
     length: u16,
     bytes: void = {},
 
-    fn getRelay(self: *align(1) Self) *align(1) Relay {
+    fn getRelay(self: ZCM) Relay.RSelf {
         return std.mem.bytesAsValue(Relay, &self.bytes);
     }
-    fn getConnection(self: *align(1) Self) *align(1) Connection {
+    fn getConnection(self: ZCM) Connection.CSelf {
         return std.mem.bytesAsValue(Connection, &self.bytes);
     }
 
-    pub fn getSaprusTypePayload(self: *align(1) Self) Error!(union(PacketType) {
+    pub fn getSaprusTypePayload(self: ZCM) Error!(union(PacketType) {
         relay: *align(1) Relay,
         file_transfer: void,
         connection: *align(1) Connection,
@@ -92,36 +100,77 @@ pub const ZeroCopyMessage = packed struct {
         };
     }
 
-    pub fn toNativeBytes() void {}
-    pub fn toNetworkBytes() void {}
+    pub fn nativeFromNetworkEndian(self: ZCM) Error!void {
+        self.type = @enumFromInt(bigToNative(
+            @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
+            @intFromEnum(self.type),
+        ));
+        self.length = bigToNative(@TypeOf(self.length), self.length);
+        try switch (try self.getSaprusTypePayload()) {
+            .relay => {},
+            .connection => |*con| con.*.nativeFromNetworkEndian(),
+            .file_transfer => Error.NotImplementedSaprusType,
+            else => Error.UnknownSaprusType,
+        };
+    }
+
+    pub fn networkFromNativeEndian(self: ZCM) Error!void {
+        try switch (try self.getSaprusTypePayload()) {
+            .relay => {},
+            .connection => |*con| con.*.networkFromNativeEndian(),
+            .file_transfer => Error.NotImplementedSaprusType,
+            else => Error.UnknownSaprusType,
+        };
+        self.type = @enumFromInt(nativeToBig(
+            @typeInfo(@TypeOf(self.type)).@"enum".tag_type,
+            @intFromEnum(self.type),
+        ));
+        self.length = nativeToBig(@TypeOf(self.length), self.length);
+    }
+
+    pub fn fromBytesUnchecked(bytes: []u8) ZCM {
+        return @ptrCast(bytes.ptr);
+    }
+
+    pub fn fromBytes(bytes: []u8) !ZCM {
+        const res: ZCM = @ptrCast(bytes.ptr);
+        return if (bytes.len == res.length + @sizeOf(Self)) res else Error.InvalidMessage;
+    }
 };
 
+const ZCM = *align(1) ZeroCopyMessage;
+
 test "testing variable length zero copy struct" {
     const gpa = std.testing.allocator;
-    const bytes = try gpa.alloc(u8, @sizeOf(ZeroCopyMessage) + 64);
+    const payload_len = 48;
+    const bytes = try gpa.alloc(u8, @sizeOf(ZeroCopyMessage) + payload_len);
     defer gpa.free(bytes);
 
-    const zcm: *align(1) ZeroCopyMessage = @ptrCast(bytes.ptr);
+    // Create a view of the byte slice as a ZeroCopyMessage
+    const zcm: ZCM = .fromBytesUnchecked(bytes);
+
+    {
+        // Set the message values
+        zcm.type = .relay;
+        // zcm.length = payload_len;
+        const relay = (try zcm.getSaprusTypePayload()).relay;
+        relay.dest = .{ 1, 2, 3, 4 };
+        const payload = relay.getPayload();
+        const p = "Hello darkness my old friend";
+        @memcpy(payload[0..p.len], p);
+    }
+
+    {
+        // Print the message as hex using the network
+        zcm.networkFromNativeEndian() catch unreachable;
+        defer zcm.nativeFromNetworkEndian() catch unreachable;
+        std.debug.print("network bytes: {x}\n", .{bytes});
+    }
 
-    zcm.type = .relay;
-    zcm.length = 64;
-    std.debug.print("pre: {*}\n", .{zcm});
-    // 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});
     }
-    if (false) {
-        std.debug.print("{any}\n", .{zcm.getRelay()});
-        std.debug.print("{any}\n", .{zcm.getConnection()});
-        std.debug.print("{x}\n", .{std.mem.asBytes(zcm.getRelay())});
-        std.debug.print("{x}\n", .{std.mem.asBytes(zcm.getConnection())});
-    }
-    std.debug.print("{x}\n", .{bytes});
-
-    try std.testing.expect(true);
 }
 
 /// All Saprus messages
@@ -266,6 +315,7 @@ const Allocator = std.mem.Allocator;
 
 const asBytes = std.mem.asBytes;
 const nativeToBig = std.mem.nativeToBig;
+const bigToNative = std.mem.bigToNative;
 
 test "Round trip Relay toBytes and fromBytes" {
     const gpa = std.testing.allocator;