Lua绑定C++类

原文：http://blog.csdn.net/chenee543216/article/details/12074771

以下是代码：

Animal.h文件

#pragma once
#ifndef __ANIMAL_H__
#define __ANIMAL_H__

class Animal
{
public:
    Animal( const char *name );
    void setAge( int age );
    int getAge();
    void sound();
    ~Animal(void);

private:
    const char *name;
    int age;
};

#endif

Animal.cpp文件

#include "stdafx.h"
#include "Animal.h"

Animal::Animal( const char* name ):age(0)
{
    this->name = name;
}

Animal::~Animal(void)
{
    printf( "Animal destructor." );
}

void Animal::setAge( int age )
{
    this->age = age;
}

int Animal::getAge()
{
    return this->age;
}

void Animal::sound()
{
    printf("--Animal-- name: %s, age:%d
", this->name, this->age );
}

LuaAimal.h

#pragma once

#ifndef __LUA_ANIMAL__
#define __LUA_ANIMAL__

class Animal;

class LuaAnimal
{
public:
    ~LuaAnimal(void);
    static void Register( lua_State *l );
private:
    static const char *className;
    static const luaL_reg methods[];
    static const luaL_reg methods_f[];

    static int create( lua_State *l );
    static int gc_animal( lua_State *l );
    static Animal *getAnimal( lua_State *l );

    static int sound( lua_State *l );
    static int setAge(lua_State *l);
    static int getAge(lua_State *l);
};

#endif

LuaAnimal.cpp

#include "stdafx.h"
#include "LuaAnimal.h"
#include "Animal.h"
#include "Utlis.h"

const char *LuaAnimal::className = "Animal";
const luaL_reg LuaAnimal::methods[] = {
    {"sound", LuaAnimal::sound },
    {"setAge", LuaAnimal::setAge},
    {"getAge", LuaAnimal::getAge},
    {"__gc", LuaAnimal::gc_animal},
    {NULL,NULL}
};

const luaL_reg LuaAnimal::methods_f[] = {
    { "create", LuaAnimal::create },
    { NULL, NULL}
};

LuaAnimal::~LuaAnimal(void)
{
}

void LuaAnimal::Register( lua_State *l )
{
    //1. new method table for l to save functions
    lua_newtable(l);
    int methodTable = lua_gettop(l);

    //2.new metatable for L to save "__metatable", "__index",  "__gc", etc
    luaL_newmetatable(l, className );
    int metaTable = lua_gettop(l);

    //3.0 metatable["__metatable"] = methodtable;
    lua_pushliteral( l, "__metatable" );  //remove
    lua_pushvalue( l, methodTable );
    lua_settable( l, metaTable );

    //4.0 metatable["__index"] = methodtable
    lua_pushliteral( l, "__index" );
    lua_pushvalue( l, methodTable );
    lua_rawset( l, metaTable );  // the same as lua_settable(1,metatable)

    //5.0 metatable["__gc"] = gc_animal  //will be called when lua_close(l)
    lua_pushliteral( l, "__gc" );
    lua_pushcfunction( l, LuaAnimal::gc_animal );
    lua_rawset( l, metaTable );

    lua_pop(l,1);   //drop metatable

    /*6.0　for object
    name -- null set object funtion to methodtable( the table on top );
    eg: Animal a = Animal("xxx")
    a:func in this methodtable
    fill methodtable, is libname is not null,
    will create a table use the libname and push the table to stack*/
    luaL_openlib( l, NULL, methods, 0 );
    lua_pop(l,1);       //drop methodtable

    /*7.1 for class:
    name = className, so this set function to "method_f"
    eg: Animal a = Animal:create( "xx" );
        Animal:create() in this method_f tables
    */
    luaL_openlib( l, className, methods_f, 0 );  //push table[className] to stack
    lua_pop(l,1); //drop table[className]

    /*7.2 for class:
    add global function "className", so we Animal() is a global function now
    eg: Animal a = Animal("xx")
        function Animal() in lua will call create in C++
    */
    //lua_register(l, className, LuaAnimal::create );
}

int LuaAnimal::create( lua_State *l )
{
    const char*name = lua_tostring(l,-1);

    Animal *a = new Animal(name);
    void **p = (void**)lua_newuserdata( l, sizeof(void*));
    *p = a;

    luaL_getmetatable( l, className );
    lua_setmetatable( l, -2 );

    return 1;
}

Animal* LuaAnimal::getAnimal( lua_State *l )
{
    luaL_checktype( l, 1, LUA_TUSERDATA ); //indicate what type to check
    void *ud = luaL_checkudata( l, 1, className );
    if( !ud )
        luaL_typerror( l, 1, className );

    return *(Animal**)ud;
}

int LuaAnimal::gc_animal( lua_State *l )
{
    Utlis::stackDump(l);

    Animal *a = (Animal*)(*(void**)lua_touserdata(l,-1));
    delete a;
    return 0;
}

int LuaAnimal::getAge( lua_State *l )
{
    Animal *a = getAnimal(l);
    lua_pushinteger(l, a->getAge());
    return 1;
}

int LuaAnimal::setAge( lua_State *l )
{
    Animal *a = getAnimal(l);
    int age = luaL_checkint(l,2);
    a->setAge( age );
    return 0;
}

int LuaAnimal::sound( lua_State *l )
{
    Animal *a = getAnimal(l);
    a->sound();
    return 0;
}

工具类Utils，使用查看lua堆栈情况

Utils.h

#pragma once
#ifndef __UTLIS_H__
#define __UTLIS_H__

class Utlis
{
public:
    Utlis(void);
    ~Utlis(void);
    static void stackDump( lua_State *l );
};

#endif

Utils.cpp

#include "stdafx.h"
#include "Utlis.h"


Utlis::Utlis(void)
{
}


Utlis::~Utlis(void)
{
}

void Utlis::stackDump( lua_State *l )
{
    int i;
    int top = lua_gettop( l );
    printf("------start-----%d
", top);

    for( i = 1; i <= top; i++ )
    {
        int t = lua_type( l, i );
        printf("type: %s value:", lua_typename(l,t));

        switch (t)
        {
        case LUA_TSTRING:
            printf("%s", lua_tostring(l,i));
            break;
        case LUA_TBOOLEAN:
            printf( lua_toboolean(l,i)? "true" : "false" );
            break;
        case LUA_TNUMBER:
            printf("%g", lua_tonumber(l,i));
            break;

        default:
            printf("%s", lua_typename(l,t));
            break;
        }
        printf("
");
    }

    printf("------end----
" );
}

lua测试代码

main.lua

print( "test lua access C++ class" )

local function main()
  --使用luaL_openlib( l, className, methods_f, 0 )注册，
  --Animal是个table, 调用create方法
  --local s = Animal.create("xx") --lua_gettop()=1 1:xx
  local s = Animal:create("xx") --lua_gettop()=2 1:table, 2:xx, 相比.create多了一个table，指Animal本身
  s:setAge(100)
  s:sound()

  --使用lua_register(l, className, LuaAnimal::create )注册
  --Animal是个函数，直接调用方法

   --local a = Animal("ww")
   --a:setAge(20)
   --a:sound()
end

main()

最后是C++测试代码

main.cpp

// TestLua.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "Utlis.h"
#include "LuaAnimal.h"

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
    lua_State *l = lua_open();
    luaL_openlibs(l);

    LuaAnimal::Register(l);
    Utlis::stackDump(l);

    if( luaL_dofile( l, "main.lua" )){  // load and call
        Utlis::stackDump(l);
    }
    Utlis::stackDump(l);

    system("pause");
    lua_close(l);

    return 0;
}