Replace 0xFFFFFFFF with PGSQL_PARAM_NULL constant

include/PgSQL_Extended_Query_Message.h

@@ -4,6 +4,7 @@
 #include "proxysql.h"
 #include "cpp.h"
 
+constexpr uint32_t PGSQL_PARAM_NULL = 0xFFFFFFFFu;
 
 /**
  * @brief Base class for handling PostgreSQL extended query messages.
@@ -172,8 +173,6 @@ public:
 			}
 			current += sizeof(uint32_t);
 
-			constexpr uint32_t PGSQL_PARAM_NULL = 0xFFFFFFFF;
-
 			if (len != PGSQL_PARAM_NULL && len > INT32_MAX) {
 				return false; // Malformed: length does not fit into int32_t
 			}

lib/PgSQL_Extended_Query_Message.cpp

@@ -379,7 +379,7 @@ bool PgSQL_Bind_Message::parse(PtrSize_t& pkt) {
 				return false;
 			}
 			offset += sizeof(uint32_t);
-			if (param_value_len != 0xFFFFFFFF) {
+			if (param_value_len != PGSQL_PARAM_NULL) {
 				// Ensure the parameter value size is valid
 				if (offset + param_value_len > pkt_len)
 					return false;