30 files changed, 242 insertions, 219 deletions

diff --git a/src/char/HPMchar.c b/src/char/HPMchar.c
index 14d7be1a3..d3150bc11 100644
--- a/src/char/HPMchar.c
+++ b/src/char/HPMchar.c
@@ -52,9 +52,10 @@
  *
  * @see HPM_interface::data_store_validate
  */
-bool HPM_char_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **store)
+bool HPM_char_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **storeptr, bool initialize)
 {
 	switch (type) {
+		// No supported types at the moment.
 		default:
 			break;
 	}
diff --git a/src/char/HPMchar.h b/src/char/HPMchar.h
index fd07f45ed..431017b7a 100644
--- a/src/char/HPMchar.h
+++ b/src/char/HPMchar.h
@@ -13,7 +13,7 @@
 
 struct hplugin;
 
-bool HPM_char_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **store);
+bool HPM_char_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **storeptr, bool initialize);
 
 void HPM_char_plugin_load_sub(struct hplugin *plugin);
 
diff --git a/src/common/HPM.c b/src/common/HPM.c
index ce3d769ca..578e90bbc 100644
--- a/src/common/HPM.c
+++ b/src/common/HPM.c
@@ -168,120 +168,158 @@ bool hplugins_addpacket(unsigned short cmd, unsigned short length, void (*receiv
 	return true;
 }
 
-bool hplugin_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **store)
+/**
+ * Validates and if necessary initializes a plugin data store.
+ *
+ * @param type[in]         The data store type.
+ * @param storeptr[in,out] A pointer to the store.
+ * @param initialize       Whether the store should be initialized in case it isn't.
+ * @retval false if the store is an invalid or mismatching type.
+ * @retval true  if the store is a valid type.
+ *
+ * @remark
+ *     If \c storeptr is a pointer to a NULL pointer (\c storeptr itself can't
+ *     be NULL), two things may happen, depending on the \c initialize value:
+ *     if false, then \c storeptr isn't changed; if true, then \c storeptr is
+ *     initialized through \c HPM->data_store_create() and ownership is passed
+ *     to the caller.
+ */
+bool hplugin_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **storeptr, bool initialize)
 {
-	nullpo_retr(false, store);
+	struct hplugin_data_store *store;
+	nullpo_retr(false, storeptr);
+	store = *storeptr;
+	if (!initialize && store == NULL)
+		return true;
 
 	switch (type) {
 		/* core-handled */
 		case HPDT_SESSION:
-			if (!*store) {
-				*store = HPM->data_store_create();
-			}
-			return true;
-		/* goes to sub */
+			break;
 		default:
+			if (HPM->data_store_validate_sub == NULL) {
+				ShowError("HPM:validateHPData failed, type %d needs sub-handler!\n",type);
+				return false;
+			}
+			if (!HPM->data_store_validate_sub(type, storeptr, initialize)) {
+				ShowError("HPM:HPM:validateHPData failed, unknown type %d!\n",type);
+				return false;
+			}
 			break;
 	}
-	if (HPM->data_store_validate_sub) {
-		if (HPM->data_store_validate_sub(type, store))
-			return true;
-		ShowError("HPM:HPM:validateHPData failed, unknown type %d!\n",type);
-	} else {
-		ShowError("HPM:validateHPData failed, type %d needs sub-handler!\n",type);
+	if (initialize && (!store || store->type == HPDT_UNKNOWN)) {
+		HPM->data_store_create(storeptr, type);
+		store = *storeptr;
 	}
-	return false;
+	if (store->type != type) {
+		ShowError("HPM:HPM:validateHPData failed, store type mismatch %d != %d.\n",store->type, type);
+		return false;
+	}
+	return true;
 }
 
-void hplugins_addToHPData(enum HPluginDataTypes type, unsigned int pluginID, struct hplugin_data_store **storeptr, void *data, unsigned int index, bool autofree)
+/**
+ * Adds an entry to a plugin data store.
+ *
+ * @param type[in]         The store type.
+ * @param pluginID[in]     The plugin identifier.
+ * @param storeptr[in,out] A pointer to the store. The store will be initialized if necessary.
+ * @param data[in]         The data entry to add.
+ * @param classid[in]      The entry class identifier.
+ * @param autofree[in]     Whether the entry should be automatically freed when removed.
+ */
+void hplugins_addToHPData(enum HPluginDataTypes type, uint32 pluginID, struct hplugin_data_store **storeptr, void *data, uint32 classid, bool autofree)
 {
-	struct hplugin_data_entry *HPData;
-	unsigned int i;
 	struct hplugin_data_store *store;
+	struct hplugin_data_entry *entry;
+	int i;
+	nullpo_retv(storeptr);
 
-	if (!HPM->data_store_validate(type, storeptr)) {
+	if (!HPM->data_store_validate(type, storeptr, true)) {
 		/* woo it failed! */
-		ShowError("HPM:addToHPData:%s: failed, type %d (%u|%u)\n",HPM->pid2name(pluginID),type,pluginID,index);
+		ShowError("HPM:addToHPData:%s: failed, type %d (%u|%u)\n", HPM->pid2name(pluginID), type, pluginID, classid);
 		return;
 	}
 	store = *storeptr;
 
 	/* duplicate check */
-	for (i = 0; i < store->count; i++) {
-		if (store->array[i]->pluginID == pluginID && store->array[i]->type == index) {
-			ShowError("HPM:addToHPData:%s: error! attempting to insert duplicate struct of id %u and index %u\n",HPM->pid2name(pluginID),pluginID,index);
-			return;
-		}
+	ARR_FIND(0, VECTOR_LENGTH(store->entries), i, VECTOR_INDEX(store->entries, i)->pluginID == pluginID && VECTOR_INDEX(store->entries, i)->classid == classid);
+	if (i != VECTOR_LENGTH(store->entries)) {
+		ShowError("HPM:addToHPData:%s: error! attempting to insert duplicate struct of id %u and classid %u\n", HPM->pid2name(pluginID), pluginID, classid);
+		return;
 	}
 
 	/* hplugin_data_entry is always same size, probably better to use the ERS (with reasonable chunk size e.g. 10/25/50) */
-	CREATE(HPData, struct hplugin_data_entry, 1);
+	CREATE(entry, struct hplugin_data_entry, 1);
 
 	/* input */
-	HPData->pluginID = pluginID;
-	HPData->type = index;
-	HPData->flag.free = autofree ? 1 : 0;
-	HPData->data = data;
-
-	/* resize */
-	RECREATE(store->array, struct hplugin_data_entry *, ++store->count);
+	entry->pluginID = pluginID;
+	entry->classid = classid;
+	entry->flag.free = autofree ? 1 : 0;
+	entry->data = data;
 
-	store->array[store->count - 1] = HPData;
+	VECTOR_ENSURE(store->entries, 1, 1);
+	VECTOR_PUSH(store->entries, entry);
 }
 
-void *hplugins_getFromHPData(enum HPluginDataTypes type, unsigned int pluginID, struct hplugin_data_store **storeptr, unsigned int index)
+/**
+ * Retrieves an entry from a plugin data store.
+ *
+ * @param type[in]     The store type.
+ * @param pluginID[in] The plugin identifier.
+ * @param store[in]    The store.
+ * @param classid[in]  The entry class identifier.
+ *
+ * @return The retrieved entry, or NULL.
+ */
+void *hplugins_getFromHPData(enum HPluginDataTypes type, uint32 pluginID, struct hplugin_data_store *store, uint32 classid)
 {
-	unsigned int i;
-	struct hplugin_data_store *store;
+	int i;
 
-	if (!HPM->data_store_validate(type, storeptr)) {
+	if (!HPM->data_store_validate(type, &store, false)) {
 		/* woo it failed! */
-		ShowError("HPM:getFromHPData:%s: failed, type %d (%u|%u)\n",HPM->pid2name(pluginID),type,pluginID,index);
+		ShowError("HPM:getFromHPData:%s: failed, type %d (%u|%u)\n", HPM->pid2name(pluginID), type, pluginID, classid);
 		return NULL;
 	}
-	store = *storeptr;
+	if (!store)
+		return NULL;
 
-	for (i = 0; i < store->count; i++) {
-		if (store->array[i]->pluginID == pluginID && store->array[i]->type == index)
-			return store->array[i]->data;
-	}
+	ARR_FIND(0, VECTOR_LENGTH(store->entries), i, VECTOR_INDEX(store->entries, i)->pluginID == pluginID && VECTOR_INDEX(store->entries, i)->classid == classid);
+	if (i != VECTOR_LENGTH(store->entries))
+		return VECTOR_INDEX(store->entries, i)->data;
 
 	return NULL;
 }
 
-void hplugins_removeFromHPData(enum HPluginDataTypes type, unsigned int pluginID, struct hplugin_data_store **storeptr, unsigned int index)
+/**
+ * Removes an entry from a plugin data store.
+ *
+ * @param type[in]     The store type.
+ * @param pluginID[in] The plugin identifier.
+ * @param store[in]    The store.
+ * @param classid[in]  The entry class identifier.
+ */
+void hplugins_removeFromHPData(enum HPluginDataTypes type, uint32 pluginID, struct hplugin_data_store *store, uint32 classid)
 {
-	unsigned int i;
-	struct hplugin_data_store *store;
+	struct hplugin_data_entry *entry;
+	int i;
 
-	if (!HPM->data_store_validate(type, storeptr)) {
+	if (!HPM->data_store_validate(type, &store, false)) {
 		/* woo it failed! */
-		ShowError("HPM:removeFromHPData:%s: failed, type %d (%u|%u)\n",HPM->pid2name(pluginID),type,pluginID,index);
+		ShowError("HPM:removeFromHPData:%s: failed, type %d (%u|%u)\n", HPM->pid2name(pluginID), type, pluginID, classid);
 		return;
 	}
-	store = *storeptr;
-
-	for (i = 0; i < store->count; i++) {
-		if (store->array[i]->pluginID == pluginID && store->array[i]->type == index)
-			break;
-	}
-
-	if (i != store->count) {
-		unsigned int cursor;
+	if (!store)
+		return;
 
-		aFree(store->array[i]->data);/* when its removed we delete it regardless of autofree */
-		aFree(store->array[i]);
-		store->array[i] = NULL;
+	ARR_FIND(0, VECTOR_LENGTH(store->entries), i, VECTOR_INDEX(store->entries, i)->pluginID == pluginID && VECTOR_INDEX(store->entries, i)->classid == classid);
+	if (i == VECTOR_LENGTH(store->entries))
+		return;
 
-		for (i = 0, cursor = 0; i < store->count; i++) {
-			if (store->array[i] == NULL)
-				continue;
-			if (i != cursor)
-				store->array[cursor] = store->array[i];
-			cursor++;
-		}
-		store->count = cursor;
-	}
+	entry = VECTOR_INDEX(store->entries, i);
+	VECTOR_ERASE(store->entries, i); // Erase and compact
+	aFree(entry->data); // when it's removed we delete it regardless of autofree
+	aFree(entry);
 }
 
 /* TODO: add ability for tracking using pID for the upcoming runtime load/unload support. */
@@ -765,25 +803,30 @@ bool hplugins_parse_conf(const char *w1, const char *w2, enum HPluginConfType po
 }
 
 /**
- * Helper to destroy and release an interface's hplugin_data store.
+ * Helper to destroy an interface's hplugin_data store and release any owned memory.
  *
- * @param hdata The hplugin_data store. The pointer will be freed.
+ * The pointer will be cleared.
+ *
+ * @param storeptr[in,out] A pointer to the plugin data store.
  */
-void hplugin_data_store_destroy(struct hplugin_data_store *store)
+void hplugin_data_store_destroy(struct hplugin_data_store **storeptr)
 {
-	unsigned int i;
-
-	if (!store)
+	struct hplugin_data_store *store;
+	nullpo_retv(storeptr);
+	store = *storeptr;
+	if (store == NULL)
 		return;
 
-	for (i = 0; i < store->count; i++) {
-		if (store->array[i]->flag.free) {
-			aFree(store->array[i]->data);
+	while (VECTOR_LENGTH(store->entries) > 0) {
+		struct hplugin_data_entry *entry = VECTOR_POP(store->entries);
+		if (entry->flag.free) {
+			aFree(entry->data);
 		}
-		aFree(store->array[i]);
+		aFree(entry);
 	}
-	aFree(store->array);
+	VECTOR_CLEAR(store->entries);
 	aFree(store);
+	*storeptr = NULL;
 }
 
 /**
@@ -792,13 +835,21 @@ void hplugin_data_store_destroy(struct hplugin_data_store *store)
  * The store is owned by the caller, and it should be eventually destroyed by
  * \c hdata_destroy.
  *
- * @return An initialized hplugin_data store.
+ * @param storeptr[in,out] A pointer to the data store to initialize.
+ * @param type[in]         The store type.
  */
-struct hplugin_data_store *hplugin_data_store_create(void)
+void hplugin_data_store_create(struct hplugin_data_store **storeptr, enum HPluginDataTypes type)
 {
 	struct hplugin_data_store *store;
-	CREATE(store, struct hplugin_data_store, 1);
-	return store;
+	nullpo_retv(storeptr);
+
+	if (*storeptr == NULL) {
+		CREATE(*storeptr, struct hplugin_data_store, 1);
+	}
+	store = *storeptr;
+
+	store->type = type;
+	VECTOR_INIT(store->entries);
 }
 
 /**
diff --git a/src/common/HPM.h b/src/common/HPM.h
index 1d13a178f..5420e5300 100644
--- a/src/common/HPM.h
+++ b/src/common/HPM.h
@@ -65,18 +65,24 @@ struct hpm_symbol {
 	void *ptr;        ///< The symbol value
 };
 
+/**
+ * A plugin custom data, to be injected in various interfaces and objects.
+ */
 struct hplugin_data_entry {
-	unsigned int pluginID;
-	unsigned int type;
+	uint32 pluginID; ///< The owner plugin identifier.
+	uint32 classid;  ///< The entry's object type, managed by the plugin (for plugins that need more than one entry).
 	struct {
-		unsigned int free : 1;
+		unsigned int free : 1; ///< Whether the entry data should be automatically cleared by the HPM.
 	} flag;
-	void *data;
+	void *data;      ///< The entry data.
 };
 
+/**
+ * A store for plugin custom data entries.
+ */
 struct hplugin_data_store {
-	struct hplugin_data_entry **array;
-	unsigned int count;
+	enum HPluginDataTypes type;                       ///< The store type.
+	VECTOR_DECL(struct hplugin_data_entry *) entries; ///< The store entries.
 };
 
 struct HPluginPacket {
@@ -144,11 +150,11 @@ struct HPM_interface {
 	void (*datacheck_init) (const struct s_HPMDataCheck *src, unsigned int length, int version);
 	void (*datacheck_final) (void);
 
-	struct hplugin_data_store *(*data_store_create) (void);
-	void (*data_store_destroy) (struct hplugin_data_store *store);
-	bool (*data_store_validate) (enum HPluginDataTypes type, struct hplugin_data_store **store);
+	void (*data_store_create) (struct hplugin_data_store **storeptr, enum HPluginDataTypes type);
+	void (*data_store_destroy) (struct hplugin_data_store **storeptr);
+	bool (*data_store_validate) (enum HPluginDataTypes type, struct hplugin_data_store **storeptr, bool initialize);
 	/* for server-specific HPData e.g. map_session_data */
-	bool (*data_store_validate_sub) (enum HPluginDataTypes type, struct hplugin_data_store **store);
+	bool (*data_store_validate_sub) (enum HPluginDataTypes type, struct hplugin_data_store **storeptr, bool initialize);
 };
 
 CMDLINEARG(loadplugin);
diff --git a/src/common/HPMi.h b/src/common/HPMi.h
index d92503a91..9a61dd256 100644
--- a/src/common/HPMi.h
+++ b/src/common/HPMi.h
@@ -60,19 +60,23 @@ enum HPluginHookType {
 	HOOK_TYPE_POST,
 };
 
+/**
+ * Data types for plugin custom data.
+ */
 enum HPluginDataTypes {
-	HPDT_SESSION,
-	HPDT_MSD,
-	HPDT_NPCD,
-	HPDT_MAP,
-	HPDT_INSTANCE,
-	HPDT_GUILD,
-	HPDT_PARTY,
-	HPDT_MOBDB,
-	HPDT_MOBDATA,
-	HPDT_ITEMDATA,
-	HPDT_BGDATA,
-	HPDT_AUTOTRADE_VEND,
+	HPDT_UNKNOWN,        ///< Unknown type (such as an uninitialized store).
+	HPDT_SESSION,        ///< For struct socket_data.
+	HPDT_MSD,            ///< For struct map_session_data.
+	HPDT_NPCD,           ///< For struct npc_data.
+	HPDT_MAP,            ///< For struct map_data.
+	HPDT_INSTANCE,       ///< For struct instance_data.
+	HPDT_GUILD,          ///< For struct guild.
+	HPDT_PARTY,          ///< For struct party_data.
+	HPDT_MOBDB,          ///< For struct mob_db.
+	HPDT_MOBDATA,        ///< For struct mob_data.
+	HPDT_ITEMDATA,       ///< For struct item_data.
+	HPDT_BGDATA,         ///< For struct battleground_data.
+	HPDT_AUTOTRADE_VEND, ///< For struct autotrade_vending.
 };
 
 /* used in macros and conf storage */
@@ -97,53 +101,53 @@ enum HPluginConfType {
 #define addArg(name, param,func,help) (HPMi->addArg(HPMi->pid,(name),(param),(cmdline_arg_ ## func),(help)))
 /* HPData handy redirects */
 /* session[] */
-#define addToSession(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_SESSION,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromSession(ptr,index) (HPMi->getFromHPData(HPDT_SESSION,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromSession(ptr,index) (HPMi->removeFromHPData(HPDT_SESSION,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToSession(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_SESSION,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromSession(ptr,classid) (HPMi->getFromHPData(HPDT_SESSION,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromSession(ptr,classid) (HPMi->removeFromHPData(HPDT_SESSION,HPMi->pid,(ptr)->hdata,(classid)))
 /* map_session_data */
-#define addToMSD(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_MSD,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromMSD(ptr,index) (HPMi->getFromHPData(HPDT_MSD,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromMSD(ptr,index) (HPMi->removeFromHPData(HPDT_MSD,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToMSD(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_MSD,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromMSD(ptr,classid) (HPMi->getFromHPData(HPDT_MSD,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromMSD(ptr,classid) (HPMi->removeFromHPData(HPDT_MSD,HPMi->pid,(ptr)->hdata,(classid)))
 /* npc_data */
-#define addToNPCD(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_NPCD,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromNPCD(ptr,index) (HPMi->getFromHPData(HPDT_NPCD,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromNPCD(ptr,index) (HPMi->removeFromHPData(HPDT_NPCD,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToNPCD(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_NPCD,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromNPCD(ptr,classid) (HPMi->getFromHPData(HPDT_NPCD,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromNPCD(ptr,classid) (HPMi->removeFromHPData(HPDT_NPCD,HPMi->pid,(ptr)->hdata,(classid)))
 /* map_data */
-#define addToMAPD(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_MAP,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromMAPD(ptr,index) (HPMi->getFromHPData(HPDT_MAP,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromMAPD(ptr,index) (HPMi->removeFromHPData(HPDT_MAP,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToMAPD(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_MAP,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromMAPD(ptr,classid) (HPMi->getFromHPData(HPDT_MAP,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromMAPD(ptr,classid) (HPMi->removeFromHPData(HPDT_MAP,HPMi->pid,(ptr)->hdata,(classid)))
 /* party_data */
-#define addToPAD(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_PARTY,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromPAD(ptr,index) (HPMi->getFromHPData(HPDT_PARTY,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromPAD(ptr,index) (HPMi->removeFromHPData(HPDT_PARTY,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToPAD(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_PARTY,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromPAD(ptr,classid) (HPMi->getFromHPData(HPDT_PARTY,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromPAD(ptr,classid) (HPMi->removeFromHPData(HPDT_PARTY,HPMi->pid,(ptr)->hdata,(classid)))
 /* guild */
-#define addToGLD(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_GUILD,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromGLD(ptr,index) (HPMi->getFromHPData(HPDT_GUILD,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromGLD(ptr,index) (HPMi->removeFromHPData(HPDT_GUILD,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToGLD(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_GUILD,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromGLD(ptr,classid) (HPMi->getFromHPData(HPDT_GUILD,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromGLD(ptr,classid) (HPMi->removeFromHPData(HPDT_GUILD,HPMi->pid,(ptr)->hdata,(classid)))
 /* instance_data */
-#define addToINSTD(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_INSTANCE,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromINSTD(ptr,index) (HPMi->getFromHPData(HPDT_INSTANCE,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromINSTD(ptr,index) (HPMi->removeFromHPData(HPDT_INSTANCE,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToINSTD(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_INSTANCE,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromINSTD(ptr,classid) (HPMi->getFromHPData(HPDT_INSTANCE,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromINSTD(ptr,classid) (HPMi->removeFromHPData(HPDT_INSTANCE,HPMi->pid,(ptr)->hdata,(classid)))
 /* mob_db */
-#define addToMOBDB(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_MOBDB,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromMOBDB(ptr,index) (HPMi->getFromHPData(HPDT_MOBDB,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromMOBDB(ptr,index) (HPMi->removeFromHPData(HPDT_MOBDB,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToMOBDB(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_MOBDB,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromMOBDB(ptr,classid) (HPMi->getFromHPData(HPDT_MOBDB,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromMOBDB(ptr,classid) (HPMi->removeFromHPData(HPDT_MOBDB,HPMi->pid,(ptr)->hdata,(classid)))
 /* mob_data */
-#define addToMOBDATA(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_MOBDATA,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromMOBDATA(ptr,index) (HPMi->getFromHPData(HPDT_MOBDATA,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromMOBDATA(ptr,index) (HPMi->removeFromHPData(HPDT_MOBDATA,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToMOBDATA(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_MOBDATA,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromMOBDATA(ptr,classid) (HPMi->getFromHPData(HPDT_MOBDATA,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromMOBDATA(ptr,classid) (HPMi->removeFromHPData(HPDT_MOBDATA,HPMi->pid,(ptr)->hdata,(classid)))
 /* item_data */
-#define addToITEMDATA(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_ITEMDATA,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromITEMDATA(ptr,index) (HPMi->getFromHPData(HPDT_ITEMDATA,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromITEMDATA(ptr,index) (HPMi->removeFromHPData(HPDT_ITEMDATA,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToITEMDATA(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_ITEMDATA,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromITEMDATA(ptr,classid) (HPMi->getFromHPData(HPDT_ITEMDATA,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromITEMDATA(ptr,classid) (HPMi->removeFromHPData(HPDT_ITEMDATA,HPMi->pid,(ptr)->hdata,(classid)))
 /* battleground_data */
-#define addToBGDATA(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_BGDATA,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromBGDATA(ptr,index) (HPMi->getFromHPData(HPDT_BGDATA,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromBGDATA(ptr,index) (HPMi->removeFromHPData(HPDT_BGDATA,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToBGDATA(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_BGDATA,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromBGDATA(ptr,classid) (HPMi->getFromHPData(HPDT_BGDATA,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromBGDATA(ptr,classid) (HPMi->removeFromHPData(HPDT_BGDATA,HPMi->pid,(ptr)->hdata,(classid)))
 /* autotrade_vending */
-#define addToATVEND(ptr,data,index,autofree) (HPMi->addToHPData(HPDT_AUTOTRADE_VEND,HPMi->pid,&(ptr)->hdata,(data),(index),(autofree)))
-#define getFromATVEND(ptr,index) (HPMi->getFromHPData(HPDT_AUTOTRADE_VEND,HPMi->pid,&(ptr)->hdata,(index)))
-#define removeFromATVEND(ptr,index) (HPMi->removeFromHPData(HPDT_AUTOTRADE_VEND,HPMi->pid,&(ptr)->hdata,(index)))
+#define addToATVEND(ptr,data,classid,autofree) (HPMi->addToHPData(HPDT_AUTOTRADE_VEND,HPMi->pid,&(ptr)->hdata,(data),(classid),(autofree)))
+#define getFromATVEND(ptr,classid) (HPMi->getFromHPData(HPDT_AUTOTRADE_VEND,HPMi->pid,(ptr)->hdata,(classid)))
+#define removeFromATVEND(ptr,classid) (HPMi->removeFromHPData(HPDT_AUTOTRADE_VEND,HPMi->pid,(ptr)->hdata,(classid)))
 
 /// HPMi->addCommand
 #define addAtcommand(cname,funcname) do { \
@@ -206,9 +210,9 @@ struct HPMi_interface {
 	bool (*addScript) (char *name, char *args, bool (*func)(struct script_state *st), bool isDeprecated);
 	void (*addCPCommand) (char *name, CParseFunc func);
 	/* HPM Custom Data */
-	void (*addToHPData) (enum HPluginDataTypes type, unsigned int pluginID, struct hplugin_data_store **storeptr, void *data, unsigned int index, bool autofree);
-	void *(*getFromHPData) (enum HPluginDataTypes type, unsigned int pluginID, struct hplugin_data_store **storeptr, unsigned int index);
-	void (*removeFromHPData) (enum HPluginDataTypes type, unsigned int pluginID, struct hplugin_data_store **storeptr, unsigned int index);
+	void (*addToHPData) (enum HPluginDataTypes type, uint32 pluginID, struct hplugin_data_store **storeptr, void *data, uint32 classid, bool autofree);
+	void *(*getFromHPData) (enum HPluginDataTypes type, uint32 pluginID, struct hplugin_data_store *store, uint32 classid);
+	void (*removeFromHPData) (enum HPluginDataTypes type, uint32 pluginID, struct hplugin_data_store *store, uint32 classid);
 	/* packet */
 	bool (*addPacket) (unsigned short cmd, unsigned short length, void (*receive)(int fd), unsigned int point, unsigned int pluginID);
 	/* Hooking */
diff --git a/src/common/mmo.h b/src/common/mmo.h
index cbda0e91b..73d4510a1 100644
--- a/src/common/mmo.h
+++ b/src/common/mmo.h
@@ -661,9 +661,7 @@ struct guild {
 	unsigned short instances;
 
 	struct channel_data *channel;
-
-	/* HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 struct guild_castle {
diff --git a/src/common/socket.c b/src/common/socket.c
index 842f9ba87..a26873b67 100644
--- a/src/common/socket.c
+++ b/src/common/socket.c
@@ -637,8 +637,7 @@ static void delete_session(int fd)
 		aFree(sockt->session[fd]->wdata);
 		if( sockt->session[fd]->session_data )
 			aFree(sockt->session[fd]->session_data);
-		HPM->data_store_destroy(sockt->session[fd]->hdata);
-		sockt->session[fd]->hdata = NULL;
+		HPM->data_store_destroy(&sockt->session[fd]->hdata);
 		aFree(sockt->session[fd]);
 		sockt->session[fd] = NULL;
 	}
diff --git a/src/common/socket.h b/src/common/socket.h
index 510eac575..a2dea8b74 100644
--- a/src/common/socket.h
+++ b/src/common/socket.h
@@ -104,8 +104,7 @@ struct socket_data {
 	ParseFunc func_parse;
 
 	void* session_data; // stores application-specific data related to the session
-
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store.
 };
 
 struct hSockOpt {
diff --git a/src/login/HPMlogin.c b/src/login/HPMlogin.c
index ce88728fe..b900f28fe 100644
--- a/src/login/HPMlogin.c
+++ b/src/login/HPMlogin.c
@@ -37,9 +37,10 @@
  *
  * @see HPM_interface::data_store_validate
  */
-bool HPM_login_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **store)
+bool HPM_login_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **storeptr, bool initialize)
 {
 	switch (type) {
+		// No supported types at the moment
 		default:
 			break;
 	}
diff --git a/src/login/HPMlogin.h b/src/login/HPMlogin.h
index 1f08a8666..35d4bd01c 100644
--- a/src/login/HPMlogin.h
+++ b/src/login/HPMlogin.h
@@ -13,7 +13,7 @@
 
 struct hplugin;
 
-bool HPM_login_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **store);
+bool HPM_login_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **storeptr, bool initialize);
 
 void HPM_login_plugin_load_sub(struct hplugin *plugin);
 
diff --git a/src/map/HPMmap.c b/src/map/HPMmap.c
index ddffb5519..edbe74039 100644
--- a/src/map/HPMmap.c
+++ b/src/map/HPMmap.c
@@ -90,7 +90,7 @@ unsigned int atcommand_list_items = 0;
  *
  * @see HPM_interface::data_store_validate
  */
-bool HPM_map_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **store)
+bool HPM_map_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **storeptr, bool initialize)
 {
 	switch (type) {
 		case HPDT_MSD:
@@ -104,9 +104,7 @@ bool HPM_map_data_store_validate(enum HPluginDataTypes type, struct hplugin_data
 		case HPDT_ITEMDATA:
 		case HPDT_BGDATA:
 		case HPDT_AUTOTRADE_VEND:
-			if (!*store) {
-				*store = HPM->data_store_create();
-			}
+			// Initialized by the caller.
 			return true;
 		default:
 			break;
diff --git a/src/map/HPMmap.h b/src/map/HPMmap.h
index 10bdf0ba7..b1957b139 100644
--- a/src/map/HPMmap.h
+++ b/src/map/HPMmap.h
@@ -15,7 +15,7 @@
 struct hplugin;
 struct map_session_data;
 
-bool HPM_map_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **store);
+bool HPM_map_data_store_validate(enum HPluginDataTypes type, struct hplugin_data_store **storeptr, bool initialize);
 
 bool HPM_map_add_atcommand(char *name, AtCommandFunc func);
 void HPM_map_atcommands(void);
diff --git a/src/map/battleground.c b/src/map/battleground.c
index 46d695272..be6b7a863 100644
--- a/src/map/battleground.c
+++ b/src/map/battleground.c
@@ -881,8 +881,7 @@ void do_init_battleground(bool minimal) {
 int bg_team_db_final(DBKey key, DBData *data, va_list ap) {
 	struct battleground_data* bgd = DB->data2ptr(data);
 
-	HPM->data_store_destroy(bgd->hdata);
-	bgd->hdata = NULL;
+	HPM->data_store_destroy(&bgd->hdata);
 
 	return 0;
 }
diff --git a/src/map/battleground.h b/src/map/battleground.h
index 0280407a2..dcf92d6d8 100644
--- a/src/map/battleground.h
+++ b/src/map/battleground.h
@@ -53,8 +53,7 @@ struct battleground_data {
 	// Logout Event
 	char logout_event[EVENT_NAME_LENGTH];
 	char die_event[EVENT_NAME_LENGTH];
-	/* HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 struct bg_arena {
diff --git a/src/map/guild.c b/src/map/guild.c
index 2dca97502..f8798f821 100644
--- a/src/map/guild.c
+++ b/src/map/guild.c
@@ -1763,8 +1763,7 @@ int guild_broken(int guild_id,int flag)
 	if( g->instance )
 		aFree(g->instance);
 
-	HPM->data_store_destroy(g->hdata);
-	g->hdata = NULL;
+	HPM->data_store_destroy(&g->hdata);
 
 	idb_remove(guild->db,guild_id);
 	return 0;
@@ -2250,8 +2249,7 @@ void do_final_guild(void) {
 			aFree(g->instance);
 			g->instance = NULL;
 		}
-		HPM->data_store_destroy(g->hdata);
-		g->hdata = NULL;
+		HPM->data_store_destroy(&g->hdata);
 	}
 
 	dbi_destroy(iter);
diff --git a/src/map/instance.c b/src/map/instance.c
index 7213c43a1..0936a5ace 100644
--- a/src/map/instance.c
+++ b/src/map/instance.c
@@ -588,8 +588,7 @@ void instance_destroy(int instance_id) {
 	instance->list[instance_id].state = INSTANCE_FREE;
 	instance->list[instance_id].num_map = 0;
 
-	HPM->data_store_destroy(instance->list[instance_id].hdata);
-	instance->list[instance_id].hdata = NULL;
+	HPM->data_store_destroy(&instance->list[instance_id].hdata);
 }
 
 /*--------------------------------------
diff --git a/src/map/instance.h b/src/map/instance.h
index f879195ef..058cd2c3d 100644
--- a/src/map/instance.h
+++ b/src/map/instance.h
@@ -52,9 +52,7 @@ struct instance_data {
 	unsigned int original_progress_timeout;
 
 	struct point respawn; ///< reload spawn
-
-	/** HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 struct instance_interface {
diff --git a/src/map/itemdb.c b/src/map/itemdb.c
index c531a4d7a..ccfff2246 100644
--- a/src/map/itemdb.c
+++ b/src/map/itemdb.c
@@ -2100,8 +2100,7 @@ void destroy_item_data(struct item_data* self, int free_self)
 		script->free_code(self->unequip_script);
 	if( self->combos )
 		aFree(self->combos);
-	HPM->data_store_destroy(self->hdata);
-	self->hdata = NULL;
+	HPM->data_store_destroy(&self->hdata);
 #if defined(DEBUG)
 	// trash item
 	memset(self, 0xDD, sizeof(struct item_data));
diff --git a/src/map/itemdb.h b/src/map/itemdb.h
index de9770aab..64b800b87 100644
--- a/src/map/itemdb.h
+++ b/src/map/itemdb.h
@@ -489,9 +489,7 @@ struct item_data {
 	/* TODO add a pointer to some sort of (struct extra) and gather all the not-common vals into it to save memory */
 	struct item_group *group;
 	struct item_package *package;
-
-	/* HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 #define itemdb_name(n)        (itemdb->search(n)->name)
diff --git a/src/map/map.c b/src/map/map.c
index 0ed7072d2..b142ed1f3 100644
--- a/src/map/map.c
+++ b/src/map/map.c
@@ -3239,8 +3239,7 @@ void do_final_maps(void) {
 		if( map->list[i].qi_data )
 			aFree(map->list[i].qi_data);
 
-		HPM->data_store_destroy(map->list[i].hdata);
-		map->list[i].hdata = NULL;
+		HPM->data_store_destroy(&map->list[i].hdata);
 	}
 
 	map->zone_db_clear();
diff --git a/src/map/map.h b/src/map/map.h
index c3e426bb6..961a45793 100644
--- a/src/map/map.h
+++ b/src/map/map.h
@@ -737,9 +737,7 @@ struct map_data {
 
 	/* speeds up clif_updatestatus processing by causing hpmeter to run only when someone with the permission can view it */
 	unsigned short hpmeter_visible;
-
-	/* HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 /// Stores information about a remote map (for multi-mapserver setups).
diff --git a/src/map/mob.c b/src/map/mob.c
index 174d2e49f..01f585b6f 100644
--- a/src/map/mob.c
+++ b/src/map/mob.c
@@ -4708,8 +4708,7 @@ int do_init_mob(bool minimal) {
 void mob_destroy_mob_db(int index)
 {
 	struct mob_db *data = mob->db_data[index];
-	HPM->data_store_destroy(data->hdata);
-	data->hdata = NULL;
+	HPM->data_store_destroy(&data->hdata);
 	aFree(data);
 	mob->db_data[index] = NULL;
 }
diff --git a/src/map/mob.h b/src/map/mob.h
index 1142502f4..bb26258c6 100644
--- a/src/map/mob.h
+++ b/src/map/mob.h
@@ -140,9 +140,7 @@ struct mob_db {
 	int maxskill;
 	struct mob_skill skill[MAX_MOBSKILL];
 	struct spawn_info spawn[10];
-
-	/* HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 struct mob_data {
@@ -209,9 +207,7 @@ struct mob_data {
 	 * MvP Tombstone NPC ID
 	 **/
 	int tomb_nid;
-
-	/* HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 
diff --git a/src/map/npc.c b/src/map/npc.c
index 85de5301b..24b22beb3 100644
--- a/src/map/npc.c
+++ b/src/map/npc.c
@@ -2321,8 +2321,7 @@ int npc_unload(struct npc_data* nd, bool single)
 		nd->ud = NULL;
 	}
 
-	HPM->data_store_destroy(nd->hdata);
-	nd->hdata = NULL;
+	HPM->data_store_destroy(&nd->hdata);
 
 	aFree(nd);
 
diff --git a/src/map/npc.h b/src/map/npc.h
index 06aee3f93..bf3d1494d 100644
--- a/src/map/npc.h
+++ b/src/map/npc.h
@@ -102,8 +102,7 @@ struct npc_data {
 			char killer_name[NAME_LENGTH];
 		} tomb;
 	} u;
-	/* HPData Support for npc_data */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 
diff --git a/src/map/party.c b/src/map/party.c
index 4735dfc42..f7e7d431c 100644
--- a/src/map/party.c
+++ b/src/map/party.c
@@ -103,8 +103,7 @@ int party_db_final(DBKey key, DBData *data, va_list ap) {
 		if (p->instance)
 			aFree(p->instance);
 
-		HPM->data_store_destroy(p->hdata);
-		p->hdata = NULL;
+		HPM->data_store_destroy(&p->hdata);
 	}
 	return 0;
 }
@@ -600,8 +599,7 @@ int party_broken(int party_id)
 	if( p->instance )
 		aFree(p->instance);
 
-	HPM->data_store_destroy(p->hdata);
-	p->hdata = NULL;
+	HPM->data_store_destroy(&p->hdata);
 
 	idb_remove(party->db,party_id);
 	return 0;
diff --git a/src/map/party.h b/src/map/party.h
index 960e6da08..df7c03f05 100644
--- a/src/map/party.h
+++ b/src/map/party.h
@@ -35,9 +35,7 @@ struct party_data {
 		unsigned snovice :1; ///< There's a Super Novice
 		unsigned tk : 1;     ///< There's a taekwon
 	} state;
-
-	/* HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 #define PB_NOTICE_LENGTH (36 + 1)
diff --git a/src/map/pc.c b/src/map/pc.c
index fee41deff..99f5b867e 100644
--- a/src/map/pc.c
+++ b/src/map/pc.c
@@ -11332,8 +11332,7 @@ void pc_autotrade_populate(struct map_session_data *sd) {
 
 	pc->autotrade_update(sd,PAUC_START);
 
-	HPM->data_store_destroy(data->hdata);
-	data->hdata = NULL;
+	HPM->data_store_destroy(&data->hdata);
 
 	idb_remove(pc->at_db, sd->status.char_id);
 }
@@ -11343,8 +11342,7 @@ void pc_autotrade_populate(struct map_session_data *sd) {
  */
 int pc_autotrade_final(DBKey key, DBData *data, va_list ap) {
 	struct autotrade_vending* at_v = DB->data2ptr(data);
-	HPM->data_store_destroy(at_v->hdata);
-	at_v->hdata = NULL;
+	HPM->data_store_destroy(&at_v->hdata);
 	return 0;
 }
 
diff --git a/src/map/pc.h b/src/map/pc.h
index a74bc6c80..2c8b24acf 100644
--- a/src/map/pc.h
+++ b/src/map/pc.h
@@ -539,9 +539,7 @@ END_ZEROED_BLOCK;
 	unsigned short (*parse_cmd_func)(int fd, struct map_session_data *sd); ///< parse_cmd_func used by this player
 
 	unsigned char delayed_damage;//ref. counter bugreport:7307 [Ind/Hercules]
-
-	/* HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 
 	/* expiration_time timer id */
 	int expiration_tid;
@@ -756,8 +754,7 @@ struct autotrade_vending {
 	struct item list[MAX_VENDING];
 	struct s_vending vending[MAX_VENDING];
 	unsigned char vend_num;
-	/* HPM Custom Struct */
-	struct hplugin_data_store *hdata;
+	struct hplugin_data_store *hdata; ///< HPM Plugin Data Store
 };
 
 /*=====================================
diff --git a/src/map/unit.c b/src/map/unit.c
index 0f8a9d7e6..dcb5ec900 100644
--- a/src/map/unit.c
+++ b/src/map/unit.c
@@ -2654,10 +2654,7 @@ int unit_free(struct block_list *bl, clr_type clrtype) {
 				sd->quest_log = NULL;
 				sd->num_quests = sd->avail_quests = 0;
 			}
-
-			HPM->data_store_destroy(sd->hdata);
-			sd->hdata = NULL;
-
+			HPM->data_store_destroy(&sd->hdata);
 			break;
 		}
 		case BL_PET:
@@ -2768,9 +2765,7 @@ int unit_free(struct block_list *bl, clr_type clrtype) {
 			if( md->tomb_nid )
 				mob->mvptomb_destroy(md);
 
-			HPM->data_store_destroy(md->hdata);
-			md->hdata = NULL;
-
+			HPM->data_store_destroy(&md->hdata);
 			break;
 		}
 		case BL_HOM: