diff --git a/src/game/ArenaTeamHandler.cpp b/src/game/ArenaTeamHandler.cpp
index 7cab8d085..16784bbcb 100644
--- a/src/game/ArenaTeamHandler.cpp
+++ b/src/game/ArenaTeamHandler.cpp
@@ -360,7 +360,7 @@ void WorldSession::HandleArenaTeamPromoteToCaptainOpcode(WorldPacket & recv_data
     at->BroadcastPacket(&data);
 }
 
-void WorldSession::SendArenaTeamCommandResult(uint32 unk1, std::string str1, std::string str2, uint32 unk3)
+void WorldSession::SendArenaTeamCommandResult(uint32 unk1, const std::string& str1, const std::string& str2, uint32 unk3)
 {
     WorldPacket data(SMSG_ARENA_TEAM_COMMAND_RESULT, 4+str1.length()+1+str2.length()+1+4);
     data << unk1;
@@ -370,7 +370,7 @@ void WorldSession::SendArenaTeamCommandResult(uint32 unk1, std::string str1, std
     SendPacket(&data);
 }
 
-void WorldSession::BuildArenaTeamEventPacket(WorldPacket *data, uint8 eventid, uint8 str_count, std::string str1, std::string str2, std::string str3)
+void WorldSession::BuildArenaTeamEventPacket(WorldPacket *data, uint8 eventid, uint8 str_count, const std::string& str1, const std::string& str2, const std::string& str3)
 {
     data->Initialize(SMSG_ARENA_TEAM_EVENT, 1+1+1);
     *data << eventid;
diff --git a/src/game/Channel.cpp b/src/game/Channel.cpp
index 2fb8b5d09..22c1a5b1a 100644
--- a/src/game/Channel.cpp
+++ b/src/game/Channel.cpp
@@ -21,7 +21,7 @@
 #include "World.h"
 #include "SocialMgr.h"
 
-Channel::Channel(std::string name, uint32 channel_id)
+Channel::Channel(const std::string& name, uint32 channel_id)
 : m_name(name), m_announce(true), m_moderate(false), m_channelId(channel_id), m_ownerGUID(0), m_password(""), m_flags(0)
 {
     // set special flags if built-in channel
@@ -773,7 +773,7 @@ void Channel::MakeOwnerChanged(WorldPacket *data, uint64 guid)
 }
 
 // done 0x09
-void Channel::MakePlayerNotFound(WorldPacket *data, std::string name)
+void Channel::MakePlayerNotFound(WorldPacket *data, const std::string& name)
 {
     MakeNotifyPacket(data, CHAT_PLAYER_NOT_FOUND_NOTICE);
     *data << name;
diff --git a/src/game/Channel.h b/src/game/Channel.h
index fc87efdd0..c3214f824 100644
--- a/src/game/Channel.h
+++ b/src/game/Channel.h
@@ -170,7 +170,7 @@ class Channel
         void MakeNotModerator(WorldPacket *data);                               //? 0x06
         void MakePasswordChanged(WorldPacket *data, uint64 guid);               //+ 0x07
         void MakeOwnerChanged(WorldPacket *data, uint64 guid);                  //? 0x08
-        void MakePlayerNotFound(WorldPacket *data, std::string name);           //+ 0x09
+        void MakePlayerNotFound(WorldPacket *data, const std::string& name);    //+ 0x09
         void MakeNotOwner(WorldPacket *data);                                   //? 0x0A
         void MakeChannelOwner(WorldPacket *data);                               //? 0x0B
         void MakeModeChange(WorldPacket *data, uint64 guid, uint8 oldflags);    //+ 0x0C
@@ -244,14 +244,14 @@ class Channel
         }
 
     public:
-        Channel(std::string name, uint32 channel_id);
+        Channel(const std::string& name, uint32 channel_id);
         std::string GetName() const { return m_name; }
         uint32 GetChannelId() const { return m_channelId; }
         bool IsConstant() const { return m_channelId != 0; }
         bool IsAnnounce() const { return m_announce; }
         bool IsLFG() const { return GetFlags() & CHANNEL_FLAG_LFG; }
         std::string GetPassword() const { return m_password; }
-        void SetPassword(std::string npassword) { m_password = npassword; }
+        void SetPassword(const std::string& npassword) { m_password = npassword; }
         void SetAnnounce(bool nannounce) { m_announce = nannounce; }
         uint32 GetNumPlayers() const { return players.size(); }
         uint8 GetFlags() const { return m_flags; }
diff --git a/src/game/ChannelMgr.h b/src/game/ChannelMgr.h
index b3e3ac2e4..124afec5c 100644
--- a/src/game/ChannelMgr.h
+++ b/src/game/ChannelMgr.h
@@ -36,7 +36,7 @@ class ChannelMgr
                 delete itr->second;
             channels.clear();
         }
-        Channel *GetJoinChannel(std::string name, uint32 channel_id)
+        Channel *GetJoinChannel(const std::string& name, uint32 channel_id)
         {
             if(channels.count(name) == 0)
             {
@@ -45,7 +45,7 @@ class ChannelMgr
             }
             return channels[name];
         }
-        Channel *GetChannel(std::string name, Player *p)
+        Channel *GetChannel(const std::string& name, Player *p)
         {
             ChannelMap::const_iterator i = channels.find(name);
 
@@ -59,7 +59,7 @@ class ChannelMgr
             else
                 return i->second;
         }
-        void LeftChannel(std::string name)
+        void LeftChannel(const std::string& name)
         {
             ChannelMap::const_iterator i = channels.find(name);
 
@@ -76,7 +76,7 @@ class ChannelMgr
         }
     private:
         ChannelMap channels;
-        void MakeNotOnPacket(WorldPacket *data, std::string name)
+        void MakeNotOnPacket(WorldPacket *data, const std::string& name)
         {
             data->Initialize(SMSG_CHANNEL_NOTIFY, (1+10));  // we guess size
             (*data) << (uint8)0x05 << name;
diff --git a/src/game/Chat.cpp b/src/game/Chat.cpp
index aa2ad5a0b..3c21a28ca 100644
--- a/src/game/Chat.cpp
+++ b/src/game/Chat.cpp
@@ -706,7 +706,7 @@ void ChatHandler::PSendSysMessage(const char *format, ...)
     SendSysMessage(str);
 }
 
-bool ChatHandler::ExecuteCommandInTable(ChatCommand *table, const char* text, std::string fullcmd)
+bool ChatHandler::ExecuteCommandInTable(ChatCommand *table, const char* text, const std::string& fullcmd)
 {
     char const* oldtext = text;
     std::string cmd = "";
diff --git a/src/game/Chat.h b/src/game/Chat.h
index 73e0d6d50..bd66f6877 100644
--- a/src/game/Chat.h
+++ b/src/game/Chat.h
@@ -80,7 +80,7 @@ class ChatHandler
 
         void SendGlobalSysMessage(const char *str);
 
-        bool ExecuteCommandInTable(ChatCommand *table, const char* text, std::string fullcommand);
+        bool ExecuteCommandInTable(ChatCommand *table, const char* text, const std::string& fullcommand);
         bool ShowHelpForCommand(ChatCommand *table, const char* cmd);
         bool ShowHelpForSubCommands(ChatCommand *table, char const* cmd, char const* subcmd);
 
diff --git a/src/game/GMTicketMgr.h b/src/game/GMTicketMgr.h
index 01e00874d..5f7bf69ea 100644
--- a/src/game/GMTicketMgr.h
+++ b/src/game/GMTicketMgr.h
@@ -31,7 +31,7 @@ class GMTicket
         {
         }
 
-        GMTicket(uint32 guid, std::string text, time_t update) : m_guid(guid), m_text(text), m_lastUpdate(update)
+        GMTicket(uint32 guid, const std::string& text, time_t update) : m_guid(guid), m_text(text), m_lastUpdate(update)
         {
 
         }
diff --git a/src/game/GossipDef.cpp b/src/game/GossipDef.cpp
index a690254e2..ed9ebb3e5 100644
--- a/src/game/GossipDef.cpp
+++ b/src/game/GossipDef.cpp
@@ -34,7 +34,7 @@ GossipMenu::~GossipMenu()
     ClearMenu();
 }
 
-void GossipMenu::AddMenuItem(uint8 Icon, std::string Message, uint32 dtSender, uint32 dtAction, std::string BoxMessage, uint32 BoxMoney, bool Coded)
+void GossipMenu::AddMenuItem(uint8 Icon, const std::string& Message, uint32 dtSender, uint32 dtAction, const std::string& BoxMessage, uint32 BoxMoney, bool Coded)
 {
     ASSERT( m_gItems.size() <= GOSSIP_MAX_MENU_ITEMS  );
 
@@ -51,7 +51,7 @@ void GossipMenu::AddMenuItem(uint8 Icon, std::string Message, uint32 dtSender, u
     m_gItems.push_back(gItem);
 }
 
-void GossipMenu::AddMenuItem(uint8 Icon, std::string Message, bool Coded)
+void GossipMenu::AddMenuItem(uint8 Icon, const std::string& Message, bool Coded)
 {
     AddMenuItem( Icon, Message, 0, 0, "", 0, Coded);
 }
@@ -341,7 +341,7 @@ void QuestMenu::ClearMenu()
     m_qItems.clear();
 }
 
-void PlayerMenu::SendQuestGiverQuestList( QEmote eEmote, std::string Title, uint64 npcGUID )
+void PlayerMenu::SendQuestGiverQuestList( QEmote eEmote, const std::string& Title, uint64 npcGUID )
 {
     WorldPacket data( SMSG_QUESTGIVER_QUEST_LIST, 100 );    // guess size
     data << uint64(npcGUID);
diff --git a/src/game/GossipDef.h b/src/game/GossipDef.h
index ba5b36008..7cde0c3b1 100644
--- a/src/game/GossipDef.h
+++ b/src/game/GossipDef.h
@@ -101,8 +101,8 @@ class MANGOS_DLL_SPEC GossipMenu
         GossipMenu();
         ~GossipMenu();
 
-        void AddMenuItem(uint8 Icon, std::string Message, bool Coded = false);
-        void AddMenuItem(uint8 Icon, std::string Message, uint32 dtSender, uint32 dtAction, std::string BoxMessage, uint32 BoxMoney, bool Coded = false);
+        void AddMenuItem(uint8 Icon, const std::string& Message, bool Coded = false);
+        void AddMenuItem(uint8 Icon, const std::string& Message, uint32 dtSender, uint32 dtAction, const std::string& BoxMessage, uint32 BoxMoney, bool Coded = false);
 
         // for using from scripts, don't must be inlined
         void AddMenuItem(uint8 Icon, char const* Message, bool Coded = false);
@@ -195,7 +195,7 @@ class MANGOS_DLL_SPEC PlayerMenu
         /*********************************************************/
         void SendQuestGiverStatus( uint8 questStatus, uint64 npcGUID );
 
-        void SendQuestGiverQuestList( QEmote eEmote, std::string Title, uint64 npcGUID );
+        void SendQuestGiverQuestList( QEmote eEmote, const std::string& Title, uint64 npcGUID );
 
         void SendQuestQueryResponse ( Quest const *pQuest );
         void SendQuestGiverQuestDetails( Quest const *pQuest, uint64 npcGUID, bool ActivateAccept);
diff --git a/src/game/Guild.cpp b/src/game/Guild.cpp
index 19f6214b8..8076757b5 100644
--- a/src/game/Guild.cpp
+++ b/src/game/Guild.cpp
@@ -517,7 +517,7 @@ void Guild::SetOFFNOTE(uint64 guid,std::string offnote)
     CharacterDatabase.PExecute("UPDATE guild_member SET offnote = '%s' WHERE guid = '%u'", offnote.c_str(), itr->first);
 }
 
-void Guild::BroadcastToGuild(WorldSession *session, std::string msg, uint32 language)
+void Guild::BroadcastToGuild(WorldSession *session, const std::string& msg, uint32 language)
 {
     if (session && session->GetPlayer() && HasRankRight(session->GetPlayer()->GetRank(),GR_RIGHT_GCHATSPEAK))
     {
@@ -534,7 +534,7 @@ void Guild::BroadcastToGuild(WorldSession *session, std::string msg, uint32 lang
     }
 }
 
-void Guild::BroadcastToOfficers(WorldSession *session, std::string msg, uint32 language)
+void Guild::BroadcastToOfficers(WorldSession *session, const std::string& msg, uint32 language)
 {
     if (session && session->GetPlayer() && HasRankRight(session->GetPlayer()->GetRank(),GR_RIGHT_OFFCHATSPEAK))
     {
@@ -593,7 +593,7 @@ void Guild::CreateRank(std::string name_,uint32 rights)
     CharacterDatabase.PExecute( "INSERT INTO guild_rank (guildid,rid,rname,rights) VALUES ('%u', '%u', '%s', '%u')", Id, m_ranks.size(), name_.c_str(), rights );
 }
 
-void Guild::AddRank(std::string name_,uint32 rights, uint32 money)
+void Guild::AddRank(const std::string& name_,uint32 rights, uint32 money)
 {
     m_ranks.push_back(RankInfo(name_,rights,money));
 }
diff --git a/src/game/Guild.h b/src/game/Guild.h
index a97a8cfb0..952468a26 100644
--- a/src/game/Guild.h
+++ b/src/game/Guild.h
@@ -242,7 +242,7 @@ struct MemberSlot
 
 struct RankInfo
 {
-    RankInfo(std::string _name, uint32 _rights, uint32 _money) : name(_name), rights(_rights), BankMoneyPerDay(_money)
+    RankInfo(const std::string& _name, uint32 _rights, uint32 _money) : name(_name), rights(_rights), BankMoneyPerDay(_money)
     {
         for(uint8 i = 0; i < GUILD_BANK_MAX_TABS; ++i)
         {
@@ -307,8 +307,8 @@ class Guild
         bool FillPlayerData(uint64 guid, MemberSlot* memslot);
         void LoadPlayerStatsByGuid(uint64 guid);
 
-        void BroadcastToGuild(WorldSession *session, std::string msg, uint32 language = LANG_UNIVERSAL);
-        void BroadcastToOfficers(WorldSession *session, std::string msg, uint32 language = LANG_UNIVERSAL);
+        void BroadcastToGuild(WorldSession *session, const std::string& msg, uint32 language = LANG_UNIVERSAL);
+        void BroadcastToOfficers(WorldSession *session, const std::string& msg, uint32 language = LANG_UNIVERSAL);
         void BroadcastPacketToRank(WorldPacket *packet, uint32 rankId);
         void BroadcastPacket(WorldPacket *packet);
 
@@ -405,7 +405,7 @@ class Guild
         bool   AddGBankItemToDB(uint32 GuildId, uint32 BankTab , uint32 BankTabSlot , uint32 GUIDLow, uint32 Entry );
 
     protected:
-        void AddRank(std::string name,uint32 rights,uint32 money);
+        void AddRank(const std::string& name,uint32 rights,uint32 money);
 
         uint32 Id;
         std::string name;
diff --git a/src/game/GuildHandler.cpp b/src/game/GuildHandler.cpp
index d40bb9b4d..8b093b808 100644
--- a/src/game/GuildHandler.cpp
+++ b/src/game/GuildHandler.cpp
@@ -730,7 +730,7 @@ void WorldSession::HandleGuildDelRankOpcode(WorldPacket& /*recvPacket*/)
     guild->Roster(this);
 }
 
-void WorldSession::SendGuildCommandResult(uint32 typecmd,std::string str,uint32 cmdresult)
+void WorldSession::SendGuildCommandResult(uint32 typecmd, const std::string& str,uint32 cmdresult)
 {
     WorldPacket data(SMSG_GUILD_COMMAND_RESULT, (8+str.size()+1));
     data << typecmd;
diff --git a/src/game/Mail.cpp b/src/game/Mail.cpp
index 06499d15b..24dbe1f09 100644
--- a/src/game/Mail.cpp
+++ b/src/game/Mail.cpp
@@ -352,7 +352,7 @@ void WorldSession::HandleReturnToSender(WorldPacket & recv_data )
     pl->SendMailResult(mailId, MAIL_RETURNED_TO_SENDER, 0);
 }
 
-void WorldSession::SendReturnToSender(uint8 messageType, uint32 sender_acc, uint32 sender_guid, uint32 receiver_guid, std::string subject, uint32 itemTextId, MailItemsInfo *mi, uint32 money, uint16 mailTemplateId )
+void WorldSession::SendReturnToSender(uint8 messageType, uint32 sender_acc, uint32 sender_guid, uint32 receiver_guid, const std::string& subject, uint32 itemTextId, MailItemsInfo *mi, uint32 money, uint16 mailTemplateId )
 {
     if(messageType != MAIL_NORMAL)                          // return only to players
     {
diff --git a/src/game/NPCHandler.cpp b/src/game/NPCHandler.cpp
index 4303e1a6c..a54ce7628 100644
--- a/src/game/NPCHandler.cpp
+++ b/src/game/NPCHandler.cpp
@@ -114,7 +114,7 @@ void WorldSession::SendTrainerList( uint64 guid )
     SendTrainerList( guid, str );
 }
 
-void WorldSession::SendTrainerList( uint64 guid,std::string strTitle )
+void WorldSession::SendTrainerList( uint64 guid, const std::string& strTitle )
 {
     sLog.outDebug( "WORLD: SendTrainerList" );
 
diff --git a/src/game/Object.h b/src/game/Object.h
index 16e1fbfdf..6abd05203 100644
--- a/src/game/Object.h
+++ b/src/game/Object.h
@@ -407,7 +407,7 @@ class MANGOS_DLL_SPEC WorldObject : public Object
         InstanceData* GetInstanceData();
 
         const char* GetName() const { return m_name.c_str(); }
-        void SetName(std::string newname) { m_name=newname; }
+        void SetName(const std::string& newname) { m_name=newname; }
 
         virtual const char* GetNameForLocaleIdx(int32 /*locale_idx*/) const { return GetName(); }
 
diff --git a/src/game/ObjectMgr.cpp b/src/game/ObjectMgr.cpp
index a936c0cc2..3ac130ff2 100644
--- a/src/game/ObjectMgr.cpp
+++ b/src/game/ObjectMgr.cpp
@@ -199,7 +199,7 @@ Guild * ObjectMgr::GetGuildById(const uint32 GuildId) const
     return NULL;
 }
 
-Guild * ObjectMgr::GetGuildByName(std::string guildname) const
+Guild * ObjectMgr::GetGuildByName(const std::string& guildname) const
 {
     for(GuildSet::const_iterator itr = mGuildSet.begin(); itr != mGuildSet.end(); ++itr)
         if ((*itr)->GetName() == guildname)
@@ -235,7 +235,7 @@ ArenaTeam* ObjectMgr::GetArenaTeamById(const uint32 ArenaTeamId) const
     return NULL;
 }
 
-ArenaTeam* ObjectMgr::GetArenaTeamByName(std::string arenateamname) const
+ArenaTeam* ObjectMgr::GetArenaTeamByName(const std::string& arenateamname) const
 {
     for(ArenaTeamSet::const_iterator itr = mArenaTeamSet.begin(); itr != mArenaTeamSet.end(); ++itr)
         if ((*itr)->GetName() == arenateamname)
@@ -1380,7 +1380,7 @@ uint32 ObjectMgr::GetPlayerAccountIdByGUID(const uint64 &guid) const
     return 0;
 }
 
-uint32 ObjectMgr::GetPlayerAccountIdByPlayerName(std::string name) const
+uint32 ObjectMgr::GetPlayerAccountIdByPlayerName(const std::string& name) const
 {
     QueryResult *result = CharacterDatabase.PQuery("SELECT account FROM characters WHERE name = '%s'", name.c_str());
     if(result)
@@ -6135,7 +6135,7 @@ bool isValidString(std::wstring wstr, uint32 strictMask, bool numericOrSpace, bo
     return false;
 }
 
-bool ObjectMgr::IsValidName( std::string name, bool create )
+bool ObjectMgr::IsValidName( const std::string& name, bool create )
 {
     std::wstring wname;
     if(!Utf8toWStr(name,wname))
@@ -6149,7 +6149,7 @@ bool ObjectMgr::IsValidName( std::string name, bool create )
     return isValidString(wname,strictMask,false,create);
 }
 
-bool ObjectMgr::IsValidCharterName( std::string name )
+bool ObjectMgr::IsValidCharterName( const std::string& name )
 {
     std::wstring wname;
     if(!Utf8toWStr(name,wname))
@@ -6163,7 +6163,7 @@ bool ObjectMgr::IsValidCharterName( std::string name )
     return isValidString(wname,strictMask,true);
 }
 
-bool ObjectMgr::IsValidPetName( std::string name )
+bool ObjectMgr::IsValidPetName( const std::string& name )
 {
     std::wstring wname;
     if(!Utf8toWStr(name,wname))
@@ -6792,7 +6792,7 @@ void ObjectMgr::LoadGameTele()
     sLog.outString( ">> Loaded %u game tele's", count );
 }
 
-GameTele const* ObjectMgr::GetGameTele(std::string name) const
+GameTele const* ObjectMgr::GetGameTele(const std::string& name) const
 {
     // explicit name case
     std::wstring wname;
@@ -6835,7 +6835,7 @@ bool ObjectMgr::AddGameTele(GameTele& tele)
         new_id,tele.position_x,tele.position_y,tele.position_z,tele.orientation,tele.mapId,tele.name.c_str());
 }
 
-bool ObjectMgr::DeleteGameTele(std::string name)
+bool ObjectMgr::DeleteGameTele(const std::string& name)
 {
     // explicit name case
     std::wstring wname;
diff --git a/src/game/ObjectMgr.h b/src/game/ObjectMgr.h
index 1c408ce63..fa594e055 100644
--- a/src/game/ObjectMgr.h
+++ b/src/game/ObjectMgr.h
@@ -313,13 +313,13 @@ class ObjectMgr
 
         Guild* GetGuildByLeader(uint64 const&guid) const;
         Guild* GetGuildById(const uint32 GuildId) const;
-        Guild* GetGuildByName(std::string guildname) const;
+        Guild* GetGuildByName(const std::string& guildname) const;
         std::string GetGuildNameById(const uint32 GuildId) const;
         void AddGuild(Guild* guild) { mGuildSet.insert( guild ); }
         void RemoveGuild(Guild* guild) { mGuildSet.erase( guild ); }
 
         ArenaTeam* GetArenaTeamById(const uint32 ArenaTeamId) const;
-        ArenaTeam* GetArenaTeamByName(std::string ArenaTeamName) const;
+        ArenaTeam* GetArenaTeamByName(const std::string& ArenaTeamName) const;
         ArenaTeam* GetArenaTeamByCapitan(uint64 const& guid) const;
         void AddArenaTeam(ArenaTeam* arenateam) { mArenaTeamSet.insert( arenateam ); }
         void RemoveArenaTeam(ArenaTeam* arenateam) { mArenaTeamSet.erase( arenateam ); }
@@ -405,7 +405,7 @@ class ObjectMgr
         bool GetPlayerNameByGUID(const uint64 &guid, std::string &name) const;
         uint32 GetPlayerTeamByGUID(const uint64 &guid) const;
         uint32 GetPlayerAccountIdByGUID(const uint64 &guid) const;
-        uint32 GetPlayerAccountIdByPlayerName(std::string name) const;
+        uint32 GetPlayerAccountIdByPlayerName(const std::string& name) const;
 
         uint32 GetNearestTaxiNode( float x, float y, float z, uint32 mapid );
         void GetTaxiPath( uint32 source, uint32 destination, uint32 &path, uint32 &cost);
@@ -698,15 +698,15 @@ class ObjectMgr
 
         // reserved names
         void LoadReservedPlayersNames();
-        bool IsReservedName(std::string name) const
+        bool IsReservedName(const std::string& name) const
         {
             return m_ReservedNames.find(name) != m_ReservedNames.end();
         }
 
         // name with valid structure and symbols
-        static bool IsValidName( std::string name, bool create = false );
-        static bool IsValidCharterName( std::string name );
-        static bool IsValidPetName( std::string name );
+        static bool IsValidName( const std::string& name, bool create = false );
+        static bool IsValidCharterName( const std::string& name );
+        static bool IsValidPetName( const std::string& name );
 
         static bool CheckDeclinedNames(std::wstring mainpart, DeclinedName const& names);
 
@@ -730,10 +730,10 @@ class ObjectMgr
             if(itr==m_GameTeleMap.end()) return NULL;
             return &itr->second;
         }
-        GameTele const* GetGameTele(std::string name) const;
+        GameTele const* GetGameTele(const std::string& name) const;
         GameTeleMap const& GetGameTeleMap() const { return m_GameTeleMap; }
         bool AddGameTele(GameTele& data);
-        bool DeleteGameTele(std::string name);
+        bool DeleteGameTele(const std::string& name);
 
         CacheNpcOptionList const& GetNpcOptions() const { return m_mCacheNpcOptionList; }
 
diff --git a/src/game/PetHandler.cpp b/src/game/PetHandler.cpp
index eb51544d3..c1d21e131 100644
--- a/src/game/PetHandler.cpp
+++ b/src/game/PetHandler.cpp
@@ -668,7 +668,7 @@ void WorldSession::HandlePetCastSpellOpcode( WorldPacket& recvPacket )
     }
 }
 
-void WorldSession::SendPetNameInvalid(uint32 error, std::string name, DeclinedName *declinedName)
+void WorldSession::SendPetNameInvalid(uint32 error, const std::string& name, DeclinedName *declinedName)
 {
     WorldPacket data(SMSG_PET_NAME_INVALID, 4 + name.size() + 1 + 1);
     data << uint32(error);
diff --git a/src/game/Player.cpp b/src/game/Player.cpp
index 5a517f45d..277d9a341 100644
--- a/src/game/Player.cpp
+++ b/src/game/Player.cpp
@@ -182,7 +182,7 @@ void PlayerTaxi::AppendTaximaskTo( ByteBuffer& data, bool all )
     }
 }
 
-bool PlayerTaxi::LoadTaxiDestinationsFromString( std::string values )
+bool PlayerTaxi::LoadTaxiDestinationsFromString( const std::string& values )
 {
     ClearTaxiDestinations();
 
@@ -476,7 +476,7 @@ void Player::CleanupsBeforeDelete()
     Unit::CleanupsBeforeDelete();
 }
 
-bool Player::Create( uint32 guidlow, std::string name, uint8 race, uint8 class_, uint8 gender, uint8 skin, uint8 face, uint8 hairStyle, uint8 hairColor, uint8 facialHair, uint8 outfitId )
+bool Player::Create( uint32 guidlow, const std::string& name, uint8 race, uint8 class_, uint8 gender, uint8 skin, uint8 face, uint8 hairStyle, uint8 hairColor, uint8 facialHair, uint8 outfitId )
 {
     //FIXME: outfitId not used in player creating
 
@@ -15751,7 +15751,7 @@ void Player::Uncharm()
     charm->RemoveSpellsCausingAura(SPELL_AURA_MOD_POSSESS);
 }
 
-void Player::BuildPlayerChat(WorldPacket *data, uint8 msgtype, std::string text, uint32 language) const
+void Player::BuildPlayerChat(WorldPacket *data, uint8 msgtype, const std::string& text, uint32 language) const
 {
     *data << (uint8)msgtype;
     *data << (uint32)language;
@@ -15763,28 +15763,28 @@ void Player::BuildPlayerChat(WorldPacket *data, uint8 msgtype, std::string text,
     *data << (uint8)chatTag();
 }
 
-void Player::Say(const std::string text, const uint32 language)
+void Player::Say(const std::string& text, const uint32 language)
 {
     WorldPacket data(SMSG_MESSAGECHAT, 200);
     BuildPlayerChat(&data, CHAT_MSG_SAY, text, language);
     SendMessageToSetInRange(&data,sWorld.getConfig(CONFIG_LISTEN_RANGE_SAY),true);
 }
 
-void Player::Yell(const std::string text, const uint32 language)
+void Player::Yell(const std::string& text, const uint32 language)
 {
     WorldPacket data(SMSG_MESSAGECHAT, 200);
     BuildPlayerChat(&data, CHAT_MSG_YELL, text, language);
     SendMessageToSetInRange(&data,sWorld.getConfig(CONFIG_LISTEN_RANGE_YELL),true);
 }
 
-void Player::TextEmote(const std::string text)
+void Player::TextEmote(const std::string& text)
 {
     WorldPacket data(SMSG_MESSAGECHAT, 200);
     BuildPlayerChat(&data, CHAT_MSG_EMOTE, text, LANG_UNIVERSAL);
     SendMessageToSetInRange(&data,sWorld.getConfig(CONFIG_LISTEN_RANGE_TEXTEMOTE),true, !sWorld.getConfig(CONFIG_ALLOW_TWO_SIDE_INTERACTION_CHAT) );
 }
 
-void Player::Whisper(std::string text, uint32 language,uint64 receiver)
+void Player::Whisper(const std::string& text, uint32 language,uint64 receiver)
 {
     if (language != LANG_ADDON)                             // if not addon data
         language = LANG_UNIVERSAL;                          // whispers should always be readable
diff --git a/src/game/Player.h b/src/game/Player.h
index bc7e3d39c..89bc27b99 100644
--- a/src/game/Player.h
+++ b/src/game/Player.h
@@ -859,7 +859,7 @@ class MANGOS_DLL_SPEC PlayerTaxi
         void AppendTaximaskTo(ByteBuffer& data,bool all);
 
         // Destinations
-        bool LoadTaxiDestinationsFromString(std::string values);
+        bool LoadTaxiDestinationsFromString(const std::string& values);
         std::string SaveTaxiDestinationsToString();
 
         void ClearTaxiDestinations() { m_TaxiDestinations.clear(); }
@@ -912,7 +912,7 @@ class MANGOS_DLL_SPEC Player : public Unit
         }
         void SummonIfPossible(bool agree);
 
-        bool Create( uint32 guidlow, std::string name, uint8 race, uint8 class_, uint8 gender, uint8 skin, uint8 face, uint8 hairStyle, uint8 hairColor, uint8 facialHair, uint8 outfitId );
+        bool Create( uint32 guidlow, const std::string& name, uint8 race, uint8 class_, uint8 gender, uint8 skin, uint8 face, uint8 hairStyle, uint8 hairColor, uint8 facialHair, uint8 outfitId );
 
         void Update( uint32 time );
 
@@ -1004,11 +1004,11 @@ class MANGOS_DLL_SPEC Player : public Unit
         GuardianPetList const& GetGuardians() const { return m_guardianPets; }
         void Uncharm();
 
-        void Say(std::string text, const uint32 language);
-        void Yell(std::string text, const uint32 language);
-        void TextEmote(std::string text);
-        void Whisper(std::string text, const uint32 language,uint64 receiver);
-        void BuildPlayerChat(WorldPacket *data, uint8 msgtype, std::string text, uint32 language) const;
+        void Say(const std::string& text, const uint32 language);
+        void Yell(const std::string& text, const uint32 language);
+        void TextEmote(const std::string& text);
+        void Whisper(const std::string& text, const uint32 language,uint64 receiver);
+        void BuildPlayerChat(WorldPacket *data, uint8 msgtype, const std::string& text, uint32 language) const;
 
         /*********************************************************/
         /***                    STORAGE SYSTEM                 ***/
diff --git a/src/game/PlayerDump.cpp b/src/game/PlayerDump.cpp
index b7e66c968..b533cab6c 100644
--- a/src/game/PlayerDump.cpp
+++ b/src/game/PlayerDump.cpp
@@ -337,7 +337,7 @@ std::string PlayerDumpWriter::GetDump(uint32 guid)
     return dump;
 }
 
-DumpReturn PlayerDumpWriter::WriteDump(std::string file, uint32 guid)
+DumpReturn PlayerDumpWriter::WriteDump(const std::string& file, uint32 guid)
 {
     FILE *fout = fopen(file.c_str(), "w");
     if (!fout)
@@ -353,7 +353,7 @@ DumpReturn PlayerDumpWriter::WriteDump(std::string file, uint32 guid)
 // Reading - High-level functions
 #define ROLLBACK(DR) {CharacterDatabase.RollbackTransaction(); fclose(fin); return (DR);}
 
-DumpReturn PlayerDumpReader::LoadDump(std::string file, uint32 account, std::string name, uint32 guid)
+DumpReturn PlayerDumpReader::LoadDump(const std::string& file, uint32 account, std::string name, uint32 guid)
 {
     // check character count
     {
diff --git a/src/game/PlayerDump.h b/src/game/PlayerDump.h
index 2e83102f9..5991b7445 100644
--- a/src/game/PlayerDump.h
+++ b/src/game/PlayerDump.h
@@ -92,7 +92,7 @@ class PlayerDumpWriter : public PlayerDump
         PlayerDumpWriter() {}
 
         std::string GetDump(uint32 guid);
-        DumpReturn WriteDump(std::string file, uint32 guid);
+        DumpReturn WriteDump(const std::string& file, uint32 guid);
     private:
         typedef std::set<uint32> GUIDs;
 
@@ -111,7 +111,7 @@ class PlayerDumpReader : public PlayerDump
     public:
         PlayerDumpReader() {}
 
-        DumpReturn LoadDump(std::string file, uint32 account, std::string name, uint32 guid);
+        DumpReturn LoadDump(const std::string& file, uint32 account, std::string name, uint32 guid);
 };
 
 #endif
diff --git a/src/game/SocialMgr.h b/src/game/SocialMgr.h
index 8c873d8a0..0a7f822a7 100644
--- a/src/game/SocialMgr.h
+++ b/src/game/SocialMgr.h
@@ -63,7 +63,7 @@ struct FriendInfo
         Note = "";
     }
 
-    FriendInfo(uint32 flags, std::string note)
+    FriendInfo(uint32 flags, const std::string& note)
     {
         Status = FRIEND_STATUS_OFFLINE;
         Flags = flags;
diff --git a/src/game/World.cpp b/src/game/World.cpp
index 2c2e87a3d..f66846362 100644
--- a/src/game/World.cpp
+++ b/src/game/World.cpp
@@ -2281,7 +2281,7 @@ void World::KickAllLess(AccountTypes sec)
 }
 
 /// Kick (and save) the designated player
-bool World::KickPlayer(std::string playerName)
+bool World::KickPlayer(const std::string& playerName)
 {
     SessionMap::iterator itr;
 
diff --git a/src/game/World.h b/src/game/World.h
index 2f3c0be57..d5b313503 100644
--- a/src/game/World.h
+++ b/src/game/World.h
@@ -438,7 +438,7 @@ class World
         bool IsPvPRealm() { return (getConfig(CONFIG_GAME_TYPE) == REALM_TYPE_PVP || getConfig(CONFIG_GAME_TYPE) == REALM_TYPE_RPPVP || getConfig(CONFIG_GAME_TYPE) == REALM_TYPE_FFA_PVP); }
         bool IsFFAPvPRealm() { return getConfig(CONFIG_GAME_TYPE) == REALM_TYPE_FFA_PVP; }
 
-        bool KickPlayer(std::string playerName);
+        bool KickPlayer(const std::string& playerName);
         void KickAll();
         void KickAllLess(AccountTypes sec);
         BanReturn BanAccount(BanMode mode, std::string nameOrIP, std::string duration, std::string reason, std::string author);
diff --git a/src/game/WorldSession.h b/src/game/WorldSession.h
index 6077d42b4..34a626d80 100644
--- a/src/game/WorldSession.h
+++ b/src/game/WorldSession.h
@@ -81,7 +81,7 @@ class MANGOS_DLL_SPEC WorldSession
         void SendPacket(WorldPacket const* packet);
         void SendNotification(const char *format,...) ATTR_PRINTF(2,3);
         void SendNotification(int32 string_id,...);
-        void SendPetNameInvalid(uint32 error, std::string name, DeclinedName *declinedName);
+        void SendPetNameInvalid(uint32 error, const std::string& name, DeclinedName *declinedName);
         void SendLfgResult(uint32 type, uint32 entry, uint8 lfg_type);
         void SendPartyResult(PartyOperation operation, const std::string& member, PartyResult res);
         void SendAreaTriggerMessage(const char* Text, ...) ATTR_PRINTF(2,3);
@@ -128,7 +128,7 @@ class MANGOS_DLL_SPEC WorldSession
         static void SendNameQueryOpcodeFromDBCallBack(QueryResult *result, uint32 accountId);
 
         void SendTrainerList( uint64 guid );
-        void SendTrainerList( uint64 guid,std::string strTitle );
+        void SendTrainerList( uint64 guid, const std::string& strTitle );
         void SendListInventory( uint64 guid );
         void SendShowBank( uint64 guid );
         void SendTabardVendorActivate( uint64 guid );
@@ -153,7 +153,7 @@ class MANGOS_DLL_SPEC WorldSession
         //mail
                                                             //used with item_page table
         bool SendItemInfo( uint32 itemid, WorldPacket data );
-        static void SendReturnToSender(uint8 messageType, uint32 sender_acc, uint32 sender_guid, uint32 receiver_guid, std::string subject, uint32 itemTextId, MailItemsInfo *mi, uint32 money, uint16 mailTemplateId = 0);
+        static void SendReturnToSender(uint8 messageType, uint32 sender_acc, uint32 sender_guid, uint32 receiver_guid, const std::string& subject, uint32 itemTextId, MailItemsInfo *mi, uint32 money, uint16 mailTemplateId = 0);
         static void SendMailTo(Player* receiver, uint8 messageType, uint8 stationery, uint32 sender_guidlow_or_entry, uint32 received_guidlow, std::string subject, uint32 itemTextId, MailItemsInfo* mi, uint32 money, uint32 COD, uint32 checked, uint32 deliver_delay = 0, uint16 mailTemplateId = 0);
 
         //auction
@@ -176,9 +176,9 @@ class MANGOS_DLL_SPEC WorldSession
         bool SendLearnNewTaxiNode( Creature* unit );
 
         // Guild/Arena Team
-        void SendGuildCommandResult(uint32 typecmd,std::string str,uint32 cmdresult);
-        void SendArenaTeamCommandResult(uint32 unk1, std::string str1, std::string str2, uint32 unk3);
-        void BuildArenaTeamEventPacket(WorldPacket *data, uint8 eventid, uint8 str_count, std::string str1, std::string str2, std::string str3);
+        void SendGuildCommandResult(uint32 typecmd, const std::string& str, uint32 cmdresult);
+        void SendArenaTeamCommandResult(uint32 unk1, const std::string& str1, const std::string& str2, uint32 unk3);
+        void BuildArenaTeamEventPacket(WorldPacket *data, uint8 eventid, uint8 str_count, const std::string& str1, const std::string& str2, const std::string& str3);
         void SendNotInArenaTeamPacket(uint8 type);
         void SendPetitionShowList( uint64 guid );
         void SendSaveGuildEmblem( uint32 msg );
diff --git a/src/realmd/AuthSocket.cpp b/src/realmd/AuthSocket.cpp
index 987e1d210..e1759e7e0 100644
--- a/src/realmd/AuthSocket.cpp
+++ b/src/realmd/AuthSocket.cpp
@@ -298,7 +298,7 @@ void AuthSocket::OnRead()
 }
 
 /// Make the SRP6 calculation from hash in dB
-void AuthSocket::_SetVSFields(std::string rI)
+void AuthSocket::_SetVSFields(const std::string& rI)
 {
     BigNumber I;
     I.SetHexStr(rI.c_str());
diff --git a/src/realmd/AuthSocket.h b/src/realmd/AuthSocket.h
index b46e1d425..0ed37587b 100644
--- a/src/realmd/AuthSocket.h
+++ b/src/realmd/AuthSocket.h
@@ -56,7 +56,7 @@ class AuthSocket: public TcpSocket
         bool _HandleXferCancel();
         bool _HandleXferAccept();
 
-        void _SetVSFields(std::string rI);
+        void _SetVSFields(const std::string& rI);
 
         FILE *pPatch;
         ZThread::Mutex patcherLock;
diff --git a/src/realmd/RealmList.cpp b/src/realmd/RealmList.cpp
index 7f4dd3e15..a25e495b0 100644
--- a/src/realmd/RealmList.cpp
+++ b/src/realmd/RealmList.cpp
@@ -42,7 +42,7 @@ void RealmList::Initialize(uint32 updateInterval)
     UpdateRealms(true);
 }
 
-void RealmList::UpdateRealm( uint32 ID, std::string name, std::string address, uint32 port, uint8 icon, uint8 color, uint8 timezone, AccountTypes allowedSecurityLevel, float popu)
+void RealmList::UpdateRealm( uint32 ID, const std::string& name, const std::string& address, uint32 port, uint8 icon, uint8 color, uint8 timezone, AccountTypes allowedSecurityLevel, float popu)
 {
     ///- Create new if not exist or update existed
     Realm& realm = m_realms[name];
diff --git a/src/realmd/RealmList.h b/src/realmd/RealmList.h
index 15095e8fa..f3e04c07d 100644
--- a/src/realmd/RealmList.h
+++ b/src/realmd/RealmList.h
@@ -56,7 +56,7 @@ class RealmList
         uint32 size() const { return m_realms.size(); }
     private:
         void UpdateRealms(bool init);
-        void UpdateRealm( uint32 ID, std::string name, std::string address, uint32 port, uint8 icon, uint8 color, uint8 timezone, AccountTypes allowedSecurityLevel, float popu);
+        void UpdateRealm( uint32 ID, const std::string& name, const std::string& address, uint32 port, uint8 icon, uint8 color, uint8 timezone, AccountTypes allowedSecurityLevel, float popu);
     private:
         RealmMap m_realms;                                  ///< Internal map of realms
         uint32   m_UpdateInterval;
diff --git a/src/shared/Common.cpp b/src/shared/Common.cpp
index 952997d3b..e7224bc5e 100644
--- a/src/shared/Common.cpp
+++ b/src/shared/Common.cpp
@@ -30,7 +30,7 @@ char const* localeNames[MAX_LOCALE] = {
   "ruRU"
 };
 
-LocaleConstant GetLocaleByName(std::string name)
+LocaleConstant GetLocaleByName(const std::string& name)
 {
     for(uint32 i = 0; i < MAX_LOCALE; ++i)
         if(name==localeNames[i])
diff --git a/src/shared/Common.h b/src/shared/Common.h
index 5c938ea67..0fc544fc6 100644
--- a/src/shared/Common.h
+++ b/src/shared/Common.h
@@ -186,7 +186,7 @@ enum LocaleConstant
 
 extern char const* localeNames[MAX_LOCALE];
 
-LocaleConstant GetLocaleByName(std::string name);
+LocaleConstant GetLocaleByName(const std::string& name);
 
 // we always use stdlibc++ std::max/std::min, undefine some not C++ standard defines (Win API and some pother platforms)
 #ifdef max
diff --git a/src/shared/Database/DBCStores.cpp b/src/shared/Database/DBCStores.cpp
index e733551d2..1385f089f 100644
--- a/src/shared/Database/DBCStores.cpp
+++ b/src/shared/Database/DBCStores.cpp
@@ -128,7 +128,7 @@ DBCStorage <WorldSafeLocsEntry> sWorldSafeLocsStore(WorldSafeLocsEntryfmt);
 
 typedef std::list<std::string> StoreProblemList;
 
-static bool LoadDBC_assert_print(uint32 fsize,uint32 rsize, std::string filename)
+static bool LoadDBC_assert_print(uint32 fsize,uint32 rsize, const std::string& filename)
 {
     sLog.outError("ERROR: Size of '%s' setted by format string (%u) not equal size of C++ structure (%u).",filename.c_str(),fsize,rsize);
 
@@ -137,7 +137,7 @@ static bool LoadDBC_assert_print(uint32 fsize,uint32 rsize, std::string filename
 }
 
 template<class T>
-inline void LoadDBC(uint32& availableDbcLocales,barGoLink& bar, StoreProblemList& errlist, DBCStorage<T>& storage, std::string dbc_path, std::string filename)
+inline void LoadDBC(uint32& availableDbcLocales,barGoLink& bar, StoreProblemList& errlist, DBCStorage<T>& storage, const std::string& dbc_path, const std::string& filename)
 {
     // compatibility format and C++ structure sizes
     assert(DBCFile::GetFormatRecordSize(storage.GetFormat()) == sizeof(T) || LoadDBC_assert_print(DBCFile::GetFormatRecordSize(storage.GetFormat()),sizeof(T),filename));
@@ -172,7 +172,7 @@ inline void LoadDBC(uint32& availableDbcLocales,barGoLink& bar, StoreProblemList
     }
 }
 
-void LoadDBCStores(std::string dataPath)
+void LoadDBCStores(const std::string& dataPath)
 {
     std::string dbcPath = dataPath+"dbc/";
 
diff --git a/src/shared/Database/DBCStores.h b/src/shared/Database/DBCStores.h
index 7811286c0..f71888d91 100644
--- a/src/shared/Database/DBCStores.h
+++ b/src/shared/Database/DBCStores.h
@@ -195,7 +195,7 @@ extern DBCStorage <TotemCategoryEntry>           sTotemCategoryStore;
 //extern DBCStorage <WorldMapAreaEntry>           sWorldMapAreaStore; -- use Zone2MapCoordinates and Map2ZoneCoordinates
 extern DBCStorage <WorldSafeLocsEntry>           sWorldSafeLocsStore;
 
-void LoadDBCStores(std::string dataPath);
+void LoadDBCStores(const std::string& dataPath);
 
 // script support functions
 MANGOS_DLL_SPEC DBCStorage <SoundEntriesEntry>  const* GetSoundEntriesStore();
diff --git a/src/shared/Log.cpp b/src/shared/Log.cpp
index ada02e62b..f5d05139b 100644
--- a/src/shared/Log.cpp
+++ b/src/shared/Log.cpp
@@ -43,7 +43,7 @@ Log::Log() :
     Initialize();
 }
 
-void Log::InitColors(std::string str)
+void Log::InitColors(const std::string& str)
 {
     if(str.empty())
     {
diff --git a/src/shared/Log.h b/src/shared/Log.h
index 2a4bb97e8..391a93d86 100644
--- a/src/shared/Log.h
+++ b/src/shared/Log.h
@@ -82,7 +82,7 @@ class Log : public MaNGOS::Singleton<Log, MaNGOS::ClassLevelLockable<Log, ZThrea
     }
     public:
         void Initialize();
-        void InitColors(std::string init_str);
+        void InitColors(const std::string& init_str);
         void outTitle( const char * str);
         void outCommand( uint32 account, const char * str, ...) ATTR_PRINTF(3,4);
         void outString();                                   // any log level
diff --git a/src/shared/Util.cpp b/src/shared/Util.cpp
index 0bab73ed2..eabd33ad0 100644
--- a/src/shared/Util.cpp
+++ b/src/shared/Util.cpp
@@ -131,13 +131,13 @@ std::string secsToTimeString(uint32 timeInSecs, bool shortText, bool hoursOnly)
     return ss.str();
 }
 
-uint32 TimeStringToSecs(std::string timestring)
+uint32 TimeStringToSecs(const std::string& timestring)
 {
     uint32 secs       = 0;
     uint32 buffer     = 0;
     uint32 multiplier = 0;
 
-    for(std::string::iterator itr = timestring.begin(); itr != timestring.end(); itr++ )
+    for(std::string::const_iterator itr = timestring.begin(); itr != timestring.end(); itr++ )
     {
         if(isdigit(*itr))
         {
@@ -193,7 +193,7 @@ bool IsIPAddress(char const* ipaddress)
 }
 
 /// create PID file
-uint32 CreatePIDFile(std::string filename)
+uint32 CreatePIDFile(const std::string& filename)
 {
     FILE * pid_file = fopen (filename.c_str(), "w" );
     if (pid_file == NULL)
@@ -271,7 +271,7 @@ bool Utf8toWStr(char const* utf8str, size_t csize, wchar_t* wstr, size_t& wsize)
     return true;
 }
 
-bool Utf8toWStr(std::string utf8str, std::wstring& wstr)
+bool Utf8toWStr(const std::string& utf8str, std::wstring& wstr)
 {
     try
     {
@@ -376,7 +376,7 @@ std::wstring GetMainPartOfName(std::wstring wname, uint32 declension)
     return wname;
 }
 
-bool utf8ToConsole(std::string utf8str, std::string& conStr)
+bool utf8ToConsole(const std::string& utf8str, std::string& conStr)
 {
 #if PLATFORM == PLATFORM_WINDOWS
     std::wstring wstr;
@@ -393,7 +393,7 @@ bool utf8ToConsole(std::string utf8str, std::string& conStr)
     return true;
 }
 
-bool consoleToUtf8(std::string conStr,std::string& utf8str)
+bool consoleToUtf8(const std::string& conStr,std::string& utf8str)
 {
 #if PLATFORM == PLATFORM_WINDOWS
     std::wstring wstr;
@@ -408,7 +408,7 @@ bool consoleToUtf8(std::string conStr,std::string& utf8str)
 #endif
 }
 
-bool Utf8FitTo(std::string str, std::wstring search)
+bool Utf8FitTo(const std::string& str, std::wstring search)
 {
     std::wstring temp;
 
diff --git a/src/shared/Util.h b/src/shared/Util.h
index 0b93cc985..77c2d9826 100644
--- a/src/shared/Util.h
+++ b/src/shared/Util.h
@@ -31,7 +31,7 @@ Tokens StrSplit(const std::string &src, const std::string &sep);
 void stripLineInvisibleChars(std::string &src);
 
 std::string secsToTimeString(uint32 timeInSecs, bool shortText = false, bool hoursOnly = false);
-uint32 TimeStringToSecs(std::string timestring);
+uint32 TimeStringToSecs(const std::string& timestring);
 std::string TimeToTimestampStr(time_t t);
 
 inline uint32 secsToTimeBitFields(time_t secs)
@@ -95,10 +95,10 @@ inline void ApplyPercentModFloatVar(float& var, float val, bool apply)
     var *= (apply?(100.0f+val)/100.0f : 100.0f / (100.0f+val));
 }
 
-bool Utf8toWStr(std::string utf8str, std::wstring& wstr);
+bool Utf8toWStr(const std::string& utf8str, std::wstring& wstr);
 // in wsize==max size of buffer, out wsize==real string size
 bool Utf8toWStr(char const* utf8str, size_t csize, wchar_t* wstr, size_t& wsize);
-inline bool Utf8toWStr(std::string utf8str, wchar_t* wstr, size_t& wsize)
+inline bool Utf8toWStr(const std::string& utf8str, wchar_t* wstr, size_t& wsize)
 {
     return Utf8toWStr(utf8str.c_str(), utf8str.size(), wstr, wsize);
 }
@@ -280,9 +280,9 @@ inline void wstrToLower(std::wstring& str)
 
 std::wstring GetMainPartOfName(std::wstring wname, uint32 declension);
 
-bool utf8ToConsole(std::string utf8str, std::string& conStr);
-bool consoleToUtf8(std::string conStr,std::string& utf8str);
-bool Utf8FitTo(std::string str, std::wstring search);
+bool utf8ToConsole(const std::string& utf8str, std::string& conStr);
+bool consoleToUtf8(const std::string& conStr,std::string& utf8str);
+bool Utf8FitTo(const std::string& str, std::wstring search);
 
 #if PLATFORM == PLATFORM_WINDOWS
 #define UTF8PRINTF(OUT,FRM,RESERR)                      \
@@ -311,6 +311,6 @@ bool Utf8FitTo(std::string str, std::wstring search);
 #endif
 
 bool IsIPAddress(char const* ipaddress);
-uint32 CreatePIDFile(std::string filename);
+uint32 CreatePIDFile(const std::string& filename);
 
 #endif
diff --git a/src/shared/revision_nr.h b/src/shared/revision_nr.h
index b8116e7ab..a0a977003 100644
--- a/src/shared/revision_nr.h
+++ b/src/shared/revision_nr.h
@@ -1,4 +1,4 @@
 #ifndef __REVISION_NR_H__
 #define __REVISION_NR_H__
- #define REVISION_NR "6898"
+ #define REVISION_NR "6899"
 #endif // __REVISION_NR_H__
diff --git a/src/shared/vmap/CoordModelMapping.h b/src/shared/vmap/CoordModelMapping.h
index d96107886..dd4f86cc1 100644
--- a/src/shared/vmap/CoordModelMapping.h
+++ b/src/shared/vmap/CoordModelMapping.h
@@ -43,8 +43,8 @@ namespace VMAP
             G3D::Array<std::string> iMainFiles;
             G3D::Array<std::string> iSingeFiles;
 
-            void appendToMain(std::string pStr) { iMainFiles.append(pStr); }
-            void appendToSingle(std::string pStr) { iSingeFiles.append(pStr); }
+            void appendToMain(const std::string& pStr) { iMainFiles.append(pStr); }
+            void appendToSingle(const std::string& pStr) { iSingeFiles.append(pStr); }
 
             size_t size() { return (iMainFiles.size() + iSingeFiles.size()); }
     };
@@ -113,7 +113,7 @@ namespace VMAP
 
             const NameCollection getFilenamesForCoordinate(unsigned int pMapId, int xPos, int yPos);
 
-            static unsigned int getMapIdFromFilename(std::string pName)
+            static unsigned int getMapIdFromFilename(const std::string& pName)
             {
                 size_t spos;
 
@@ -126,8 +126,8 @@ namespace VMAP
             }
 
             const G3D::Array<unsigned int>& getMaps() const { return iMapIds; }
-            bool isAlreadyProcessedSingleFile(std::string pName) const { return iProcesseSingleFiles.containsKey(pName); }
-            void addAlreadyProcessedSingleFile(std::string pName) { iProcesseSingleFiles.set(pName,pName); }
+            bool isAlreadyProcessedSingleFile(const std::string& pName) const { return iProcesseSingleFiles.containsKey(pName); }
+            void addAlreadyProcessedSingleFile(const std::string& pName) { iProcesseSingleFiles.set(pName,pName); }
 
             inline void addWorldAreaMap(unsigned int pMapId)
             {