Write the header as a packed int

this seems like the best way to do it.

1 files changed, 12 insertions, 7 deletions

diff --git a/src/saprus_message.zig b/src/saprus_message.zig
index 6c46a8f..1f1d37e 100644
--- a/src/saprus_message.zig
+++ b/src/saprus_message.zig
@@ -79,16 +79,21 @@ pub const SaprusMessage = union(SaprusPacketType) {
         // Write the payload bytes as base64 to the growable string.
         try base64Enc.encodeWriter(buf_w, payload);
 
-        // Write the packet body to the output writer
+        // At this point, payload_list contains the base64 encoded payload.
+
+        // Write the packet body to the output buf.
         try buf.*.appendSlice(asBytes(&nativeToBig(u16, @intCast(payload_list.items.len))));
 
-        var h = header;
-        inline for (@typeInfo(Header).@"struct".fields) |f| {
-            @field(h, f.name) = nativeToBig(@TypeOf(@field(h, f.name)), @field(h, f.name));
-        }
+        // Write the header bytes to the output buf.
+        const HeaderInt = @typeInfo(Header).@"struct".backing_integer.?;
+        std.mem.writePackedInt(
+            HeaderInt,
+            try buf.*.addManyAsSlice(@bitSizeOf(Header) / 8),
+            0,
+            @bitCast(header),
+            .little,
+        );
 
-        const h_bytes = asBytes(&h);
-        try buf.*.appendSlice(h_bytes[0 .. h_bytes.len - 2]);
         try buf.*.appendSlice(payload_list.items);
     }