src/script/api/script_priorityqueue.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 script_priorityqueue.cpp Implementation of ScriptPriorityQueue. */
   9
  10 #include "../../stdafx.h"
  11 #include "script_priorityqueue.hpp"
  12 #include "script_error.hpp"
  13 #include "../squirrel_helper.hpp"
  14 #include "../script_instance.hpp"
  15 #include "../../debug.h"
  16
  17 #include "../../safeguards.h"
  18
  19
  20 static bool operator==(const ScriptPriorityQueue::PriorityItem &lhs, const HSQOBJECT &rhs)
  21 {
  22         return lhs.second._type == rhs._type && lhs.second._unVal.raw == rhs._unVal.raw;
  23 }
  24
  25
  26 ScriptPriorityQueue::~ScriptPriorityQueue()
  27 {
  28         /* Release reference to stored objects. */
  29         auto inst = ScriptObject::GetActiveInstance();
  30         if (!inst->InShutdown()) {
  31                 for (auto &i : this->queue) inst->ReleaseSQObject(const_cast<HSQOBJECT *>(&i.second));
  32         }
  33 }
  34
  35 SQInteger ScriptPriorityQueue::Insert(HSQUIRRELVM vm)
  36 {
  37         HSQOBJECT item;
  38         SQInteger priority;
  39         sq_resetobject(&item);
  40         sq_getstackobj(vm, 2, &item);
  41         sq_getinteger(vm, 3, &priority);
  42
  43         sq_addref(vm, &item); // Keep object alive.
  44
  45         this->queue.emplace_back(priority, item);
  46         std::push_heap(this->queue.begin(), this->queue.end(), this->comp);
  47
  48         return SQConvert::Return<bool>::Set(vm, true);
  49 }
  50
  51 SQInteger ScriptPriorityQueue::Pop(HSQUIRRELVM vm)
  52 {
  53         if (this->IsEmpty()) {
  54                 ScriptObject::SetLastError(ScriptError::ERR_PRECONDITION_FAILED);
  55                 sq_pushnull(vm);
  56                 return 1;
  57         }
  58
  59         HSQOBJECT item = this->queue.front().second;
  60         std::pop_heap(this->queue.begin(), this->queue.end(), this->comp);
  61         this->queue.pop_back();
  62
  63         /* Store the object on the Squirrel stack before releasing it to make sure the ref count can't drop to zero. */
  64         auto ret = SQConvert::Return<HSQOBJECT>::Set(vm, item);
  65         sq_release(vm, &item);
  66         return ret;
  67 }
  68
  69 SQInteger ScriptPriorityQueue::Peek(HSQUIRRELVM vm)
  70 {
  71         if (this->IsEmpty()) {
  72                 ScriptObject::SetLastError(ScriptError::ERR_PRECONDITION_FAILED);
  73                 sq_pushnull(vm);
  74                 return 1;
  75         }
  76
  77         return SQConvert::Return<HSQOBJECT>::Set(vm, this->queue.front().second);
  78 }
  79
  80 SQInteger ScriptPriorityQueue::Exists(HSQUIRRELVM vm)
  81 {
  82         HSQOBJECT item;
  83         sq_resetobject(&item);
  84         sq_getstackobj(vm, 2, &item);
  85
  86         return SQConvert::Return<bool>::Set(vm, std::find(this->queue.cbegin(), this->queue.cend(), item) != this->queue.cend());
  87 }
  88
  89 SQInteger ScriptPriorityQueue::Clear(HSQUIRRELVM vm)
  90 {
  91         /* Release reference to stored objects. */
  92         for (auto &i : this->queue) sq_release(vm, const_cast<HSQOBJECT *>(&i.second));
  93         this->queue.clear();
  94
  95         return 0;
  96 }
  97
  98 bool ScriptPriorityQueue::IsEmpty()
  99 {
 100         return this->queue.empty();
 101 }
 102
 103 SQInteger ScriptPriorityQueue::Count()
 104 {
 105         return (SQInteger)this->queue.size();
 106 }