Add a helper for sub-packet deserialisation

src/network/core/packet.cpp

@@ -198,3 +198,12 @@ size_t Packet::RemainingBytesToTransfer() const
 	return this->Size() - this->pos;
 }
 
+bool SubPacketDeserialiser::CanDeserialiseBytes(size_t bytes_to_read, bool raise_error)
+{
+	if (this->pos + bytes_to_read > this->size) {
+		if (raise_error) this->cs->NetworkSocketHandler::MarkClosed();
+		return false;
+	}
+
+	return true;
+}

src/network/core/packet.h

@@ -187,6 +187,23 @@ public:
 		if (bytes > 0) this->pos += bytes;
 		return bytes;
 	}
+
+	NetworkSocketHandler *GetParentSocket() { return this->cs; }
+};
+
+struct SubPacketDeserialiser : public BufferDeserialisationHelper<SubPacketDeserialiser> {
+	NetworkSocketHandler *cs;
+	const byte *data;
+	size_t size;
+	PacketSize pos;
+
+	SubPacketDeserialiser(Packet *p, const byte *data, size_t size, PacketSize pos = 0) : cs(p->GetParentSocket()), data(data), size(size), pos(pos) {}
+	SubPacketDeserialiser(Packet *p, const std::vector<byte> &buffer, PacketSize pos = 0) : cs(p->GetParentSocket()), data(buffer.data()), size(buffer.size()), pos(pos) {}
+
+	const byte *GetDeserialisationBuffer() const { return this->data; }
+	size_t GetDeserialisationBufferSize() const { return this->size; }
+	PacketSize &GetDeserialisationPosition() { return this->pos; }
+	bool CanDeserialiseBytes(size_t bytes_to_read, bool raise_error);
 };
 
 #endif /* NETWORK_CORE_PACKET_H */