Release 0.1.0

gamesv/src/network.zig

@@ -0,0 +1,45 @@
+const std = @import("std");
+const proto = @import("proto");
+const pb = proto.pb;
+
+const Io = std.Io;
+const Crc32 = std.hash.Crc32;
+
+pub const Request = struct {
+    head: pb.CSHead,
+    body: []u8,
+
+    pub const ReadError = error{
+        HeadDecodeError,
+        ChecksumMismatch,
+        InvalidMessageId,
+    } || Io.Reader.Error;
+
+    pub fn read(reader: *Io.Reader) ReadError!Request {
+        const header_length = try reader.takeInt(u8, .little);
+        const body_length = try reader.takeInt(u16, .little);
+        const payload = try reader.take(header_length + body_length);
+
+        var head_reader: Io.Reader = .fixed(payload[0..header_length]);
+        const head = proto.decodeMessage(
+            &head_reader,
+            .failing, // CSHead contains only scalar fields. No allocation needed.
+            pb.CSHead,
+        ) catch return error.HeadDecodeError;
+
+        if (std.enums.fromInt(pb.CSMessageID, head.msgid) == null)
+            return error.InvalidMessageId;
+
+        const body = payload[header_length..];
+        const checksum = Crc32.hash(body);
+
+        if (checksum != head.checksum)
+            return error.ChecksumMismatch;
+
+        return .{ .head = head, .body = body };
+    }
+
+    pub fn msgId(request: *const Request) pb.CSMessageID {
+        return @enumFromInt(request.head.msgid);
+    }
+};