Misc/Util: Add a template function for returning a random element from any container

src/server/game/AI/CoreAI/UnitAI.h

@@ -160,11 +160,7 @@ class UnitAI
                     return *ritr;
                 }
                 case SELECT_TARGET_RANDOM:
-                {
-                    std::list<Unit*>::iterator itr = targetList.begin();
-                    std::advance(itr, urand(position, targetList.size()-1));
-                    return *itr;
-                }
+                    return SelectRandomContainerElement(targetList);
                 default:
                     break;
             }

src/server/game/DungeonFinding/LFGMgr.cpp

@@ -934,11 +934,8 @@ bool LFGMgr::CheckCompatibility(LfgGuidList check, LfgProposal*& pProposal)
 
     // Select a random dungeon from the compatible list
     // TODO - Select the dungeon based on group item Level, not just random
-    LfgDungeonSet::const_iterator itDungeon = compatibleDungeons.begin();
-    std::advance(itDungeon, urand(0, compatibleDungeons.size() - 1));
-
     // Create a new proposal
-    pProposal = new LfgProposal(*itDungeon);
+    pProposal = new LfgProposal(SelectRandomContainerElement(compatibleDungeons));
     pProposal->cancelTime = time_t(time(NULL)) + LFG_TIME_PROPOSAL;
     pProposal->state = LFG_PROPOSAL_INITIATING;
     pProposal->queues = check;

src/server/game/Entities/GameObject/GameObject.cpp

@@ -1400,10 +1400,7 @@ void GameObject::Use(Unit* user)
                 {
                     for (int i = 0; i < info->summoningRitual.casterTargetSpellTargets; i++)
                     {
-                        std::set<uint32>::const_iterator itr = m_unique_users.begin();
-                        std::advance(itr, rand() % m_unique_users.size());
-
-                        if (Unit* target = Unit::GetUnit(*this, uint64(*itr)))
+                        if (Unit* target = Unit::GetUnit(*this, (uint64)SelectRandomContainerElement(m_unique_users)))
                             spellCaster->CastSpell(target, info->summoningRitual.casterTargetSpell, true);
                     }
                 }

src/server/game/Entities/Unit/Unit.cpp

@@ -14938,9 +14938,7 @@ Unit* Unit::SelectNearbyTarget(float dist) const
         return NULL;
 
     // select random
-    std::list<Unit*>::const_iterator tcIter = targets.begin();
-    std::advance(tcIter, urand(0, targets.size()-1));
-    return *tcIter;
+    return SelectRandomContainerElement(targets);
 }
 
 void Unit::ApplyAttackTimePercentMod(WeaponAttackType att, float val, bool apply)

src/server/game/Loot/LootMgr.cpp

@@ -1075,9 +1075,7 @@ void LootTemplate::LootGroup::Process(Loot& loot, uint16 lootMode) const
         if (item == NULL && !EqualPossibleDrops.empty()) // If nothing selected yet - an item is taken from equal-chanced part
         {
             itemSource = 2;
-            itr = EqualPossibleDrops.begin();
-            std::advance(itr, irand(0, EqualPossibleDrops.size()-1));
-            item = &*itr;
+            item = const_cast<LootStoreItem*>(&SelectRandomContainerElement(EqualPossibleDrops));
         }
         // finish rolling
 

src/server/game/Pools/PoolMgr.cpp

@@ -476,10 +476,9 @@ void PoolGroup<Quest>::SpawnObject(ActivePoolData& spawns, uint32 limit, uint32
     {
         do
         {
-            ActivePoolObjects::iterator itr = currentQuests.begin();
-            std::advance(itr, urand(0, currentQuests.size()-1));
-            newQuests.insert(*itr);
-            currentQuests.erase(*itr);
+            uint32 questId = SelectRandomContainerElement(currentQuests);
+            newQuests.insert(questId);
+            currentQuests.erase(questId);
         } while (newQuests.size() < limit && !currentQuests.empty()); // failsafe
     }
 
@@ -489,12 +488,11 @@ void PoolGroup<Quest>::SpawnObject(ActivePoolData& spawns, uint32 limit, uint32
     // activate <limit> random quests
     do
     {
-        ActivePoolObjects::iterator itr = newQuests.begin();
-        std::advance(itr, urand(0, newQuests.size()-1));
-        spawns.ActivateObject<Quest>(*itr, poolId);
-        PoolObject tempObj(*itr, 0.0f);
+        uint32 questId = SelectRandomContainerElement(newQuests);
+        spawns.ActivateObject<Quest>(questId, poolId);
+        PoolObject tempObj(questId, 0.0f);
         Spawn1Object(&tempObj);
-        newQuests.erase(itr);
+        newQuests.erase(questId);
         --limit;
     } while (limit && !newQuests.empty());
 

src/server/game/Spells/Auras/SpellAuraEffects.cpp

@@ -5748,9 +5748,7 @@ void AuraEffect::HandlePeriodicDummyAuraTick(Unit* target, Unit* caster) const
                     if (targets.empty())
                         return;
 
-                    UnitList::const_iterator itr = targets.begin();
-                    std::advance(itr, rand()%targets.size());
-                    Unit* spellTarget = *itr;
+                    Unit* spellTarget = SelectRandomContainerElement(targets);
 
                     target->CastSpell(spellTarget, 57840, true);
                     target->CastSpell(spellTarget, 57841, true);

src/server/game/Spells/SpellEffects.cpp

@@ -1373,10 +1373,9 @@ void Spell::EffectDummy(SpellEffIndex effIndex)
                     uint32 maxTargets = std::min<uint32>(3, attackers.size());
                     for (uint32 i = 0; i < maxTargets; ++i)
                     {
-                        Unit::AttackerSet::iterator aItr = attackers.begin();
-                        std::advance(aItr, urand(0, attackers.size() - 1));
-                        AddUnitTarget(*aItr, 1);
-                        attackers.erase(aItr);
+                        Unit* attacker = SelectRandomContainerElement(attackers);
+                        AddUnitTarget(attacker, 1);
+                        attackers.erase(attacker);
                     }
 
                     // now let next effect cast spell at each target.
@@ -2621,10 +2620,7 @@ void Spell::EffectEnergize(SpellEffIndex effIndex)
         if (!avalibleElixirs.empty())
         {
             // cast random elixir on target
-            uint32 rand_spell = urand(0, avalibleElixirs.size()-1);
-            std::set<uint32>::iterator itr = avalibleElixirs.begin();
-            std::advance(itr, rand_spell);
-            m_caster->CastSpell(unitTarget, *itr, true, m_CastItem);
+            m_caster->CastSpell(unitTarget, SelectRandomContainerElement(avalibleElixirs), true, m_CastItem);
         }
     }
 }

src/server/game/World/World.cpp

@@ -2556,9 +2556,7 @@ void World::SendAutoBroadcast()
 
     std::string msg;
 
-    std::list<std::string>::const_iterator itr = m_Autobroadcasts.begin();
-    std::advance(itr, rand() % m_Autobroadcasts.size());
-    msg = *itr;
+    msg = SelectRandomContainerElement(m_Autobroadcasts);
 
     uint32 abcenter = sWorld->getIntConfig(CONFIG_AUTOBROADCAST_CENTER);
 

src/server/scripts/EasternKingdoms/MoltenCore/boss_sulfuron_harbinger.cpp

@@ -104,14 +104,7 @@ class boss_sulfuron : public CreatureScript
                             Creature* target = NULL;
                             std::list<Creature*> healers = DoFindFriendlyMissingBuff(45.0f, SPELL_INSPIRE);
                             if (!healers.empty())
-                            {
-                                std::list<Creature*>::const_iterator itr = healers.begin();
-                                std::advance(itr, urand(0, healers.size()-1));
-                                target = *itr;
-                            }
-
-                            if (target)
-                                DoCast(target, SPELL_INSPIRE);
+                                DoCast(SelectRandomContainerElement(healers), SPELL_INSPIRE);
 
                             DoCast(me, SPELL_INSPIRE);
                             events.ScheduleEvent(EVENT_INSPIRE, urand(20000, 26000));

src/server/scripts/Northrend/IcecrownCitadel/boss_blood_queen_lana_thel.cpp

@@ -480,9 +480,7 @@ class boss_blood_queen_lana_thel : public CreatureScript
                     return tempTargets.front();
                 }
 
-                std::list<Player*>::iterator itr = tempTargets.begin();
-                std::advance(itr, urand(0, tempTargets.size() - 1));
-                return *itr;
+                return SelectRandomContainerElement(tempTargets);
             }
 
             std::set<uint64> _vampires;

src/server/scripts/Northrend/IcecrownCitadel/boss_deathbringer_saurfang.cpp

@@ -1189,9 +1189,7 @@ class spell_deathbringer_blood_nova_targeting : public SpellScriptLoader
                 if (targetsAtRange < minTargets)
                     targetsAtRange = std::min<uint32>(unitList.size() - 1, minTargets);
 
-                std::list<Unit*>::iterator itr = unitList.begin();
-                std::advance(itr, urand(0, targetsAtRange));
-                target = *itr;
+                target = SelectRandomContainerElement(unitList);
                 unitList.clear();
                 unitList.push_back(target);
             }
@@ -1241,9 +1239,7 @@ class spell_deathbringer_boiling_blood : public SpellScriptLoader
                 if (unitList.empty())
                     return;
 
-                std::list<Unit*>::iterator itr = unitList.begin();
-                std::advance(itr, urand(0, unitList.size() - 1));
-                Unit* target = *itr;
+                Unit* target = SelectRandomContainerElement(unitList);
                 unitList.clear();
                 unitList.push_back(target);
             }

src/server/scripts/Northrend/IcecrownCitadel/boss_lady_deathwhisper.cpp

@@ -605,10 +605,7 @@ class boss_lady_deathwhisper : public CreatureScript
                     return;
 
                 // select random cultist
-                std::list<Creature*>::iterator cultistItr = temp.begin();
-                std::advance(cultistItr, urand(0, temp.size()-1));
-
-                Creature* cultist = *cultistItr;
+                Creature* cultist = SelectRandomContainerElement(temp);
                 DoCast(cultist, cultist->GetEntry() == NPC_CULT_FANATIC ? SPELL_DARK_TRANSFORMATION_T : SPELL_DARK_EMPOWERMENT_T, true);
                 Talk(uint8(cultist->GetEntry() == NPC_CULT_FANATIC ? SAY_DARK_TRANSFORMATION : SAY_DARK_EMPOWERMENT));
             }

src/server/scripts/Northrend/IcecrownCitadel/boss_professor_putricide.cpp

@@ -775,9 +775,7 @@ class spell_putricide_ooze_channel : public SpellScriptLoader
                     return;
                 }
 
-                std::list<Unit*>::iterator itr = targetList.begin();
-                std::advance(itr, urand(0, targetList.size() - 1));
-                Unit* target = *itr;
+                Unit* target = SelectRandomContainerElement(targetList);
                 targetList.clear();
                 targetList.push_back(target);
                 _target = target;

src/server/scripts/Northrend/IcecrownCitadel/boss_rotface.cpp

@@ -493,9 +493,7 @@ class spell_rotface_mutated_infection : public SpellScriptLoader
                 if (targets.empty())
                     return;
 
-                std::list<Unit*>::iterator itr = targets.begin();
-                std::advance(itr, urand(0, targets.size() - 1));
-                Unit* target = *itr;
+                Unit* target = SelectRandomContainerElement(targets);
                 targets.clear();
                 targets.push_back(target);
                 _target = target;

src/server/scripts/Northrend/IcecrownCitadel/boss_sindragosa.cpp

@@ -1341,9 +1341,7 @@ class spell_frostwarden_handler_order_whelp : public SpellScriptLoader
                         ++itr;
                 }
 
-                std::list<Unit*>::iterator itr = unitList.begin();
-                std::advance(itr, urand(0, unitList.size()-1));
-                Unit* target = *itr;
+                Unit* target = SelectRandomContainerElement(unitList);
                 unitList.clear();
                 unitList.push_back(target);
             }
@@ -1357,9 +1355,7 @@ class spell_frostwarden_handler_order_whelp : public SpellScriptLoader
                 if (Creature* creature = GetCaster()->ToCreature())
                     unitList.remove_if(OrderWhelpTargetSelector(creature));
 
-                std::list<Creature*>::iterator itr = unitList.begin();
-                std::advance(itr, urand(0, unitList.size()-1));
-                (*itr)->CastSpell(GetHitUnit(), uint32(GetEffectValue()), true);
+                SelectRandomContainerElement(unitList)->CastSpell(GetHitUnit(), uint32(GetEffectValue()), true);
             }
 
             void Register()

src/server/scripts/Northrend/IcecrownCitadel/boss_valithria_dreamwalker.cpp

@@ -1182,9 +1182,7 @@ class spell_dreamwalker_summoner : public SpellScriptLoader
                 if (targets.empty())
                     return;
 
-                std::list<Unit*>::iterator itr = targets.begin();
-                std::advance(itr, urand(0, targets.size() - 1));
-                Unit* target = *itr;
+                Unit* target = SelectRandomContainerElement(targets);
                 targets.clear();
                 targets.push_back(target);
             }

src/server/scripts/Northrend/IcecrownCitadel/icecrown_citadel.cpp

@@ -1361,9 +1361,7 @@ class npc_captain_arnath : public CreatureScript
                         case EVENT_ARNATH_PW_SHIELD:
                         {
                             std::list<Creature*> targets = DoFindFriendlyMissingBuff(40.0f, SPELL_POWER_WORD_SHIELD);
-                            std::list<Creature*>::iterator itr = targets.begin();
-                            std::advance(itr, urand(0, targets.size() - 1));
-                            DoCast(*itr, SPELL_POWER_WORD_SHIELD);
+                            DoCast(SelectRandomContainerElement(targets), SPELL_POWER_WORD_SHIELD);
                             Events.ScheduleEvent(EVENT_ARNATH_PW_SHIELD, urand(15000, 20000));
                             break;
                         }
@@ -1817,9 +1815,7 @@ class spell_frost_giant_death_plague : public SpellScriptLoader
                 unitList.remove_if(DeathPlagueTargetSelector(GetCaster()));
                 if (!unitList.empty())
                 {
-                    std::list<Unit*>::iterator itr = unitList.begin();
-                    std::advance(itr, urand(0, unitList.size()-1));
-                    Unit* target = *itr;
+                    Unit* target = SelectRandomContainerElement(unitList);
                     unitList.clear();
                     unitList.push_back(target);
                 }

src/server/scripts/Northrend/Ulduar/ulduar/boss_general_vezax.cpp

@@ -290,9 +290,7 @@ class boss_general_vezax : public CreatureScript
                     if (size < playersMin)
                         return NULL;
 
-                    std::list<Player*>::const_iterator itr = PlayerList.begin();
-                    std::advance(itr, urand(0, size - 1));
-                    return *itr;
+                    return SelectRandomContainerElement(PlayerList);
                 }
 
                 return NULL;

src/server/scripts/Northrend/VaultOfArchavon/boss_emalon.cpp

@@ -139,9 +139,7 @@ class boss_emalon : public CreatureScript
                         case EVENT_OVERCHARGE:
                             if (!summons.empty())
                             {
-                                std::list<uint64>::const_iterator itr = summons.begin();
-                                std::advance(itr, urand(0, summons.size()-1));
-                                Creature* minion = Unit::GetCreature(*me, *itr);
+                                Creature* minion = Unit::GetCreature(*me, SelectRandomContainerElement(summons));
                                 if (minion && minion->isAlive())
                                 {
                                     minion->CastSpell(me, SPELL_OVERCHARGED, true);

src/server/scripts/Outland/netherstorm.cpp

@@ -817,9 +817,7 @@ public:
                 }
                 if (!UnitsWithMana.empty())
                 {
-                    std::list<Unit*>::const_iterator it = UnitsWithMana.begin();
-                    std::advance(it, rand() % UnitsWithMana.size());
-                    DoCast(*it, SPELL_MANA_BURN);
+                    DoCast(SelectRandomContainerElement(UnitsWithMana), SPELL_MANA_BURN);
                     ManaBurnTimer = 8000 + (rand() % 10 * 1000); // 8-18 sec cd
                 }
                 else

src/server/scripts/Spells/spell_druid.cpp

@@ -251,10 +251,9 @@ class spell_dru_t10_restoration_4p_bonus : public SpellScriptLoader
                         return;
                     }
 
-                    std::list<Unit*>::const_iterator it2 = tempTargets.begin();
-                    std::advance(it2, urand(0, tempTargets.size() - 1));
+                    Unit* target = SelectRandomContainerElement(tempTargets);
                     unitList.clear();
-                    unitList.push_back(*it2);
+                    unitList.push_back(target);
                 }
             }
 

src/server/shared/Utilities/Util.h

@@ -648,4 +648,13 @@ public:
         return (part[el]);
     };
 };
+
+/* Select a random element from a container. Note: make sure you explicitly empty check the container */
+template <class C> typename C::value_type const& SelectRandomContainerElement(C const& container)
+{
+    C::const_iterator it = container.begin();
+    std::advance(it, urand(0, container.size() - 1));
+    return *it;
+}
+
 #endif