src/autoreplace.cpp

   1 /*
   2  * This file is part of OpenTTD.
   3  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   4  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   6  */
   7
   8 /** @file autoreplace.cpp Management of replacement lists. */
   9
  10 #include "stdafx.h"
  11 #include "command_func.h"
  12 #include "group.h"
  13 #include "autoreplace_base.h"
  14 #include "core/bitmath_func.hpp"
  15 #include "core/pool_func.hpp"
  16
  17 #include "safeguards.h"
  18
  19 /** The pool of autoreplace "orders". */
  20 EngineRenewPool _enginerenew_pool("EngineRenew");
  21 INSTANTIATE_POOL_METHODS(EngineRenew)
  22
  23 /**
  24  * Retrieves the EngineRenew that specifies the replacement of the given
  25  * engine type from the given renewlist
  26  */
  27 static EngineRenew *GetEngineReplacement(EngineRenewList erl, EngineID engine, GroupID group)
  28 {
  29         EngineRenew *er = (EngineRenew *)erl;
  30
  31         while (er != nullptr) {
  32                 if (er->from == engine && GroupIsInGroup(group, er->group_id)) return er;
  33                 er = er->next;
  34         }
  35         return nullptr;
  36 }
  37
  38 /**
  39  * Remove all engine replacement settings for the company.
  40  * @param  erl The renewlist for a given company.
  41  * @return The new renewlist for the company.
  42  */
  43 void RemoveAllEngineReplacement(EngineRenewList *erl)
  44 {
  45         EngineRenew *er = (EngineRenew *)(*erl);
  46         EngineRenew *next;
  47
  48         while (er != nullptr) {
  49                 next = er->next;
  50                 delete er;
  51                 er = next;
  52         }
  53         *erl = nullptr; // Empty list
  54 }
  55
  56 /**
  57  * Retrieve the engine replacement in a given renewlist for an original engine type.
  58  * @param erl The renewlist to search in.
  59  * @param engine Engine type to be replaced.
  60  * @param group The group related to this replacement.
  61  * @param[out] replace_when_old Set to true if the replacement should be done when old.
  62  * @return The engine type to replace with, or INVALID_ENGINE if no
  63  * replacement is in the list.
  64  */
  65 EngineID EngineReplacement(EngineRenewList erl, EngineID engine, GroupID group, bool *replace_when_old)
  66 {
  67         const EngineRenew *er = GetEngineReplacement(erl, engine, group);
  68         if (er == nullptr && (group == DEFAULT_GROUP || (Group::IsValidID(group) && !HasBit(Group::Get(group)->flags, GroupFlags::GF_REPLACE_PROTECTION)))) {
  69                 /* We didn't find anything useful in the vehicle's own group so we will try ALL_GROUP */
  70                 er = GetEngineReplacement(erl, engine, ALL_GROUP);
  71         }
  72         if (replace_when_old != nullptr) *replace_when_old = er == nullptr ? false : er->replace_when_old;
  73         return er == nullptr ? INVALID_ENGINE : er->to;
  74 }
  75
  76 /**
  77  * Add an engine replacement to the given renewlist.
  78  * @param erl The renewlist to add to.
  79  * @param old_engine The original engine type.
  80  * @param new_engine The replacement engine type.
  81  * @param group The group related to this replacement.
  82  * @param replace_when_old Replace when old or always?
  83  * @param flags The calling command flags.
  84  * @return 0 on success, CMD_ERROR on failure.
  85  */
  86 CommandCost AddEngineReplacement(EngineRenewList *erl, EngineID old_engine, EngineID new_engine, GroupID group, bool replace_when_old, DoCommandFlag flags)
  87 {
  88         /* Check if the old vehicle is already in the list */
  89         EngineRenew *er = GetEngineReplacement(*erl, old_engine, group);
  90         if (er != nullptr) {
  91                 if (flags & DC_EXEC) {
  92                         er->to = new_engine;
  93                         er->replace_when_old = replace_when_old;
  94                 }
  95                 return CommandCost();
  96         }
  97
  98         if (!EngineRenew::CanAllocateItem()) return CMD_ERROR;
  99
 100         if (flags & DC_EXEC) {
 101                 er = new EngineRenew(old_engine, new_engine);
 102                 er->group_id = group;
 103                 er->replace_when_old = replace_when_old;
 104
 105                 /* Insert before the first element */
 106                 er->next = (EngineRenew *)(*erl);
 107                 *erl = (EngineRenewList)er;
 108         }
 109
 110         return CommandCost();
 111 }
 112
 113 /**
 114  * Remove an engine replacement from a given renewlist.
 115  * @param erl The renewlist from which to remove the replacement
 116  * @param engine The original engine type.
 117  * @param group The group related to this replacement.
 118  * @param flags The calling command flags.
 119  * @return 0 on success, CMD_ERROR on failure.
 120  */
 121 CommandCost RemoveEngineReplacement(EngineRenewList *erl, EngineID engine, GroupID group, DoCommandFlag flags)
 122 {
 123         EngineRenew *er = (EngineRenew *)(*erl);
 124         EngineRenew *prev = nullptr;
 125
 126         while (er != nullptr) {
 127                 if (er->from == engine && er->group_id == group) {
 128                         if (flags & DC_EXEC) {
 129                                 if (prev == nullptr) { // First element
 130                                         /* The second becomes the new first element */
 131                                         *erl = (EngineRenewList)er->next;
 132                                 } else {
 133                                         /* Cut this element out */
 134                                         prev->next = er->next;
 135                                 }
 136                                 delete er;
 137                         }
 138                         return CommandCost();
 139                 }
 140                 prev = er;
 141                 er = er->next;
 142         }
 143
 144         return CMD_ERROR;
 145 }