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Lua: 在C++中将table如何传入到lua中

发布时间：2020-12-14 22:01:38 所属栏目：大数据 来源：网络整理
导读：例一是参考别人的： //定义函数(返回table)int func_return_table(lua_State *L){ lua_newtable(L);//创建一个表格，放在栈顶 lua_pushstring(L,"mydata");//压入key lua_pushnumber(L,66);//压入value lua_settable(L,-3);//弹出key,value，并设置到table里
例一是参考别人的：

//定义函数(返回table)
int func_return_table(lua_State *L)
{
 lua_newtable(L);//创建一个表格，放在栈顶
 lua_pushstring(L,"mydata");//压入key
 lua_pushnumber(L,66);//压入value
 lua_settable(L,-3);//弹出key,value，并设置到table里面去

 lua_pushstring(L,"subdata");//压入key
 lua_newtable(L);//压入value,也是一个table
 lua_pushstring(L,"mydata");//压入subtable的key
 lua_pushnumber(L,53);//value
 lua_settable(L,value,并设置到subtable

 lua_settable(L,-3);//这时候父table的位置还是-3,弹出key,value(subtable),并设置到table里去
 lua_pushstring(L,"mydata2");//同上
 lua_pushnumber(L,77);
 lua_settable(L,-3);
 return 1;//堆栈里现在就一个table.其他都被弹掉了。
}
输出结构体： 

{
     "mydata" = 66,"mydate2" = 77,"subdata" = 
     {
          "mydata" = 53
     }
}

这里算是一个嵌套的结构体了。

函数解释： 

lua_settable(lua_State* L,int index)

就是把表在lua堆栈中的值弹出来，index 是table 在堆栈中的位置，假如 table 在 -3,则key 应该是 -2，value 是 -1

相当于 table[key] = value.

例二：

在工作中这里我想用一个类似数组的table,类似 tableaname[n].x

代码：

struct BattleResultDamageData
{
	Uint32 nIcon;
	Uint32 nDamage;
	Uint16 nPetPos;
	Uint16 nLv;
	Uint8  nStar;
	Uint8  nEvo;
	Uint8  nCurSkin;
	Uint8  nStage;
};

static int luaGetBattleResultData(lua_State *L_)
{
	lua_newtable(L_); //创建一个表，放在栈顶
	int i = 1; //目的：类似tablename[i].id
	std::map<unsigned,BattleResultDamageData>::const_iterator map_it;
	for (map_it = SkillActObj::_BattleAtk.begin(); map_it != SkillActObj::_BattleAtk.end(); ++map_it,++i) //可忽略，目的遍历C++中的数据放在lua的table
	{
		lua_pushnumber(L_,i);
		lua_newtable(L_);
		lua_pushstring(L_,"id");
		lua_pushnumber(L_,map_it->first);
		lua_settable(L_,value，并设置到table里面去
		lua_pushstring(L_,"dmg");
		lua_pushnumber(L_,map_it->second.nDamage);
		lua_settable(L_,-3);
		lua_pushstring(L_,"icon");
		lua_pushnumber(L_,map_it->second.nIcon);
		lua_settable(L_,"lv");
		lua_pushnumber(L_,map_it->second.nLv);
		lua_settable(L_,"star");
		lua_pushnumber(L_,map_it->second.nStar);
		lua_settable(L_,"evo");
		lua_pushnumber(L_,map_it->second.nEvo);
		lua_settable(L_,"pos");
		lua_pushnumber(L_,map_it->second.nPetPos);
		lua_settable(L_,"skin");
		lua_pushnumber(L_,map_it->second.nCurSkin);
		lua_settable(L_,-3);

		lua_settable(L_,-3);
	}
        return 1;
}

在lua代码中的使用：

local buffAtk = _G.getBattleResultData();

打印的buffAtk这个table结构体信息: 

<Info>0409-210505 654 Lookup local var buffAtk
<Info>0409-210505 654 name = buffAtk	 type = table	 value = 0CB685A0
<Info>0409-210505 654 name = buffAtk[1]	 type = table	 value = 06CCEA58
<Info>0409-210505 670 name = buffAtk[1][dmg]	 type = number	 value = 89298
<Info>0409-210505 670 name = buffAtk[1][skin]	 type = number	 value = 0
<Info>0409-210505 670 name = buffAtk[1][star]	 type = number	 value = 6
<Info>0409-210505 689 name = buffAtk[1][evo]	 type = number	 value = 10
<Info>0409-210505 692 name = buffAtk[1][id]	 type = number	 value = 25165827
<Info>0409-210505 693 name = buffAtk[1][lv]	 type = number	 value = 131
<Info>0409-210505 693 name = buffAtk[1][icon]	 type = number	 value = 1090
<Info>0409-210505 693 name = buffAtk[1][pos]	 type = number	 value = 19
<Info>0409-210505 693 name = buffAtk[2]	 type = table	 value = 0CC8C038
<Info>0409-210505 693 name = buffAtk[2][dmg]	 type = number	 value = 28726
<Info>0409-210505 693 name = buffAtk[2][skin]	 type = number	 value = 0
<Info>0409-210505 710 name = buffAtk[2][star]	 type = number	 value = 6
<Info>0409-210505 711 name = buffAtk[2][evo]	 type = number	 value = 12
<Info>0409-210505 711 name = buffAtk[2][id]	 type = number	 value = 25165828
<Info>0409-210505 711 name = buffAtk[2][lv]	 type = number	 value = 90
<Info>0409-210505 711 name = buffAtk[2][icon]	 type = number	 value = 1325
<Info>0409-210505 711 name = buffAtk[2][pos]	 type = number	 value = 51
例三：

上例返回一个，这里我想返回两个tableaname[n].x
如：一个tablename1[n].x 与 另一个 tablename2[n].x

static int luaGetBattleResultData(lua_State *L_)
{
	lua_newtable(L_); // 建立一个table
	int i = 1;
	std::map<unsigned,++i)
	{	
		lua_pushnumber(L_,value，并设置到table里面去
		//...
		lua_pushstring(L_,-3);
	}

	lua_newtable(L_); //建立另一个table
	i = 1;
	for (map_it = SkillActObj::_BattleDef.begin(); map_it != SkillActObj::_BattleDef.end(); ++map_it,++i)
	{
		lua_pushnumber(L_,value，并设置到table里面去
		// ...
		lua_pushstring(L_,-3);
	}
	return 2; // 返回这两个table
}
在lua中调用： 

local buffAtk,buffDef= _G.getBattleResultData();
打印这两个table的信息： 

<Info>0409-210505 654 Lookup local var buffAtk
<Info>0409-210505 654 name = buffAtk	 type = table	 value = 0CB685A0
<Info>0409-210505 654 name = buffAtk[1]	 type = table	 value = 06CCEA58
<Info>0409-210505 670 name = buffAtk[1][dmg]	 type = number	 value = 89298
<Info>0409-210505 670 name = buffAtk[1][skin]	 type = number	 value = 0
<Info>0409-210505 670 name = buffAtk[1][star]	 type = number	 value = 6
<Info>0409-210505 689 name = buffAtk[1][evo]	 type = number	 value = 10
<Info>0409-210505 692 name = buffAtk[1][id]	 type = number	 value = 25165827
<Info>0409-210505 693 name = buffAtk[1][lv]	 type = number	 value = 131
<Info>0409-210505 693 name = buffAtk[1][icon]	 type = number	 value = 1090
<Info>0409-210505 693 name = buffAtk[1][pos]	 type = number	 value = 19
<Info>0409-210505 693 name = buffAtk[2]	 type = table	 value = 0CC8C038
<Info>0409-210505 693 name = buffAtk[2][dmg]	 type = number	 value = 28726
<Info>0409-210505 693 name = buffAtk[2][skin]	 type = number	 value = 0
<Info>0409-210505 710 name = buffAtk[2][star]	 type = number	 value = 6
<Info>0409-210505 711 name = buffAtk[2][evo]	 type = number	 value = 12
<Info>0409-210505 711 name = buffAtk[2][id]	 type = number	 value = 25165828
<Info>0409-210505 711 name = buffAtk[2][lv]	 type = number	 value = 90
<Info>0409-210505 711 name = buffAtk[2][icon]	 type = number	 value = 1325
<Info>0409-210505 711 name = buffAtk[2][pos]	 type = number	 value = 51
<Info>0409-210505 711 

<Info>0409-212740 450 Lookup local var buffDef
<Info>0409-212740 451 name = buffDef	 type = table	 value = 0CDD1EB8
<Info>0409-212740 451 name = buffDef[1]	 type = table	 value = 0CEEFCA8
<Info>0409-212740 451 name = buffDef[1][dmg]	 type = number	 value = 1992
<Info>0409-212740 451 name = buffDef[1][skin]	 type = number	 value = 0
<Info>0409-212740 466 name = buffDef[1][star]	 type = number	 value = 1
<Info>0409-212740 466 name = buffDef[1][evo]	 type = number	 value = 4
<Info>0409-212740 466 name = buffDef[1][id]	 type = number	 value = 25165829
<Info>0409-212740 482 name = buffDef[1][lv]	 type = number	 value = 85
<Info>0409-212740 482 name = buffDef[1][icon]	 type = number	 value = 1005
<Info>0409-212740 482 name = buffDef[1][pos]	 type = number	 value = 2
<Info>0409-212740 482 name = buffDef[2]	 type = table	 value = 0CEED4D0
<Info>0409-212740 482 name = buffDef[2][dmg]	 type = number	 value = 2941
<Info>0409-212740 482 name = buffDef[2][skin]	 type = number	 value = 0
<Info>0409-212740 499 name = buffDef[2][star]	 type = number	 value = 2
<Info>0409-212740 499 name = buffDef[2][evo]	 type = number	 value = 6
<Info>0409-212740 499 name = buffDef[2][id]	 type = number	 value = 25165830
<Info>0409-212740 499 name = buffDef[2][lv]	 type = number	 value = 85
<Info>0409-212740 499 name = buffDef[2][icon]	 type = number	 value = 1075
<Info>0409-212740 499 name = buffDef[2][pos]	 type = number	 value = 16
<Info>0409-212740 499 name = buffDef[3]	 type = table	 value = 0D0E83A0
<Info>0409-212740 516 name = buffDef[3][dmg]	 type = number	 value = 308
<Info>0409-212740 519 name = buffDef[3][skin]	 type = number	 value = 1
<Info>0409-212740 521 name = buffDef[3][star]	 type = number	 value = 0
<Info>0409-212740 523 name = buffDef[3][evo]	 type = number	 value = 6
<Info>0409-212740 523 name = buffDef[3][id]	 type = number	 value = 25165831
<Info>0409-212740 523 name = buffDef[3][lv]	 type = number	 value = 85
<Info>0409-212740 523 name = buffDef[3][icon]	 type = number	 value = 1080
<Info>0409-212740 523 name = buffDef[3][pos]	 type = number	 value = 17
<Info>0409-212740 523 name = buffDef[4]	 type = table	 value = 0CD85A00
<Info>0409-212740 523 name = buffDef[4][dmg]	 type = number	 value = 792
<Info>0409-212740 539 name = buffDef[4][skin]	 type = number	 value = 0
<Info>0409-212740 539 name = buffDef[4][star]	 type = number	 value = 0
<Info>0409-212740 539 name = buffDef[4][evo]	 type = number	 value = 0
<Info>0409-212740 539 name = buffDef[4][id]	 type = number	 value = 25165832
<Info>0409-212740 539 name = buffDef[4][lv]	 type = number	 value = 85
<Info>0409-212740 539 name = buffDef[4][icon]	 type = number	 value = 1145
<Info>0409-212740 539 name = buffDef[4][pos]	 type = number	 value = 30
<Info>0409-212740 554 name = buffDef[5]	 type = table	 value = 0C7CF7F8
<Info>0409-212740 554 name = buffDef[5][dmg]	 type = number	 value = 1608
<Info>0409-212740 554 name = buffDef[5][skin]	 type = number	 value = 0
<Info>0409-212740 554 name = buffDef[5][star]	 type = number	 value = 2
<Info>0409-212740 554 name = buffDef[5][evo]	 type = number	 value = 4
<Info>0409-212740 554 name = buffDef[5][id]	 type = number	 value = 25165833
<Info>0409-212740 571 name = buffDef[5][lv]	 type = number	 value = 47
<Info>0409-212740 574 name = buffDef[5][icon]	 type = number	 value = 1090
<Info>0409-212740 577 name = buffDef[5][pos]	 type = number	 value = 19
<Info>0409-212740 578

看到这，是不是感觉哪里不对？是不是感觉代码好臃肿？

下面是最最终优化后的代码：

static void setTableInt(lua_State *L_,const char *sKey,lua_Number nVal)
{
	lua_pushstring(L_,sKey);
	lua_pushnumber(L_,nVal);
	lua_settable(L_,-3);
}

static void newDmgTable(lua_State *L_,unsigned nEntityId,const BattleResultDamageData &data)
{
	lua_newtable(L_);
	setTableInt(L_,"id",nEntityId);
	setTableInt(L_,"dmg",data.nDamage);
	setTableInt(L_,"icon",data.nIcon);
	setTableInt(L_,"lv",data.nLv);
	setTableInt(L_,"star",data.nStar);
	setTableInt(L_,"evo",data.nEvo);
	setTableInt(L_,"pos",data.nPetPos);
	setTableInt(L_,"skin",data.nCurSkin);
}

static int luaGetBattleResultData(lua_State *L_)
{
	std::map<unsigned,BattleResultDamageData> *datas[] = {&SkillActObj::_BattleAtk,&SkillActObj::_BattleDef};
	for (unsigned i = 0; i < 2; ++i) 
	{
		lua_newtable(L_);	//new table
		int j = 1;
		std::map<unsigned,BattleResultDamageData>::const_iterator map_it = datas[i]->begin(),map_it_end = datas[i]->end();
		for (; map_it != map_it_end; ++map_it,++j) {
			lua_pushinteger(L_,j);
			newDmgTable(L_,map_it->first,map_it->second);	//atker or defer[id] = dmg_table;
			lua_settable(L_,-3);
		}
	}
	return 2;
}
这下是不是感觉一下子少了好多？这就是代码的重用性！

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