TProtocol: Add `flex_packet`, and make use of it in `packet`

This will be needed later on.

3 files changed, 35 insertions, 21 deletions

diff --git a/context.h b/context.h
index 24f7b2d..d7d27e8 100644
--- a/context.h
+++ b/context.h
@@ -510,6 +510,17 @@ TMenuListEntry(QuestListEntry,
 	char short_description[112];
 );
 
+// pso/TProtocol.h
+// NOTE: This is only here because of the ordering of this.
+//       In Reality, the definition of `_packet` is above `flex_packet`.
+struct _packet;
+
+template<size_t n = 0>
+union flex_packet {
+	struct _packet pkt;
+	u8 bytes[(n) ? n : sizeof(packet_header)];
+};
+
 // TMainTask.cpp
 // Const defs.
 static const int tl_object_count = 20;
@@ -775,20 +786,17 @@ struct extended_game_command {
 };
 
 // pso/TProtocol.h
-struct packet {
-	union {
-		struct {
-			packet_header header;
-			u8 data[0x7c00-sizeof(packet_header)];
-		} pkt;
-		u8 bytes[0x7c00];
-	};
-
+struct _packet {
 	void bswap() {
-		pkt.header.bswap();
+		header.bswap();
 	};
+
+	packet_header header;
+	u8 data[];
 };
 
+struct packet : public flex_packet<0x7c00> {};
+
 struct recv_packet_handlers {
 	#define o(name, ...) recv_packet_handler(name) name;
 	RECV_PACKET_HANDLERS;
diff --git a/include/pso/TProtocol.h b/include/pso/TProtocol.h
index f8943e2..d19b37d 100644
--- a/include/pso/TProtocol.h
+++ b/include/pso/TProtocol.h
@@ -26,20 +26,26 @@ extern TPlyMeetUserExtension meet_user_settings;
 extern u32 game_variations[16][2];
 extern void copy_packet(struct packet *pkt);
 
-struct packet {
-	union {
-		struct {
-			packet_header header;
-			u8 data[0x7c00-sizeof(packet_header)];
-		} pkt;
-		u8 bytes[0x7c00];
-	};
-
+// NOTE: Having this outside of `flex_packet` is required in some cases.
+//       This is because some of the senders allocate a different sized
+//       packet from what `TProtocol` uses, but also call `_packet::bswap()`.
+struct _packet {
 	void bswap() {
-		pkt.header.bswap();
+		header.bswap();
 	};
+
+	packet_header header;
+	u8 data[];
 };
 
+template<size_t n = 0>
+union flex_packet {
+	struct _packet pkt;
+	u8 bytes[(n) ? n : sizeof(packet_header)];
+};
+
+struct packet : public flex_packet<0x7c00> {};
+
 #define RECV_PACKET_HANDLERS \
 	o(handle_unused_login, void) \
 	o(handle_03_recv_regist, u8 state) \
diff --git a/src/pso/TProtocol.cpp b/src/pso/TProtocol.cpp
index 408214b..e9b3226 100644
--- a/src/pso/TProtocol.cpp
+++ b/src/pso/TProtocol.cpp
@@ -150,7 +150,7 @@ void TProtocol::recv_generate_id(packet &pkt) {
 
 void TProtocol::recv_pso_data_long(packet &pkt) {
 	TRecvPsoData &tmp = as(TRecvPsoData &, pkt);
-	pkt.bswap();
+	pkt.pkt.bswap();
 	tmp.data.recv_pso_data_buf(tmp.header.size - 4);
 };