add LEN_EMPTY

card.cpp

@@ -141,6 +141,7 @@ int32 card::get_infos(byte* buf, uint32 query_flag, int32 use_cache) {
 	if ((query_flag & QUERY_BASE_ATTACK) || (query_flag & QUERY_BASE_DEFENSE)) {
 		base_atk_def = get_base_atk_def();
 	}
+	//first 8 bytes: data length, query flag
 	p += 2;
 	if (query_flag & QUERY_CODE) {
 		*p = data.code;

ocgapi.cpp

@@ -204,8 +204,8 @@ extern "C" DECL_DLLEXPORT int32 query_card(intptr_t pduel, uint8 playerid, uint8
 		return pcard->get_infos(buf, query_flag, use_cache);
 	}
 	else {
-		*((int32*)buf) = 4;
-		return 4;
+		*((int32*)buf) = LEN_EMPTY;
+		return LEN_EMPTY;
 	}
 }
 extern "C" DECL_DLLEXPORT int32 query_field_count(intptr_t pduel, uint8 playerid, uint8 location) {
@@ -251,8 +251,8 @@ extern "C" DECL_DLLEXPORT int32 query_field_card(intptr_t pduel, uint8 playerid,
 				int32 clen = pcard->get_infos(p, query_flag, use_cache);
 				p += clen;
 			} else {
-				*((int32*)p) = 4;
-				p += 4;
+				*((int32*)p) = LEN_EMPTY;
+				p += LEN_EMPTY;
 			}
 		}
 	}
@@ -262,8 +262,8 @@ extern "C" DECL_DLLEXPORT int32 query_field_card(intptr_t pduel, uint8 playerid,
 				int32 clen = pcard->get_infos(p, query_flag, use_cache);
 				p += clen;
 			} else {
-				*((int32*)p) = 4;
-				p += 4;
+				*((int32*)p) = LEN_EMPTY;
+				p += LEN_EMPTY;
 			}
 		}
 	}

ocgapi.h

@@ -16,6 +16,8 @@
 #define DECL_DLLEXPORT
 #endif
 
+#define LEN_EMPTY 4
+
 class card;
 struct card_data;
 struct card_info;