lua --- 表操作

c api 参考手册:http://www.leeon.me/a/lua-c-api-manual

// LuaTest.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#pragma comment (lib,"Lua.lib")
#include "lua.hpp"
#include<iostream>

#define MAX_COLOR 255

//设置窗口的size
void setWinSize(char *fileName, int *width, int *height)
{
    lua_State *lua_state = luaL_newstate();
    luaL_openlibs(lua_state);

    if (luaL_loadfile(lua_state, fileName) || lua_pcall(lua_state, 0, 0, 0))
    {
        luaL_error(lua_state, "cannot run configuration fiile: %s", lua_tostring(lua_state, -1));
    }

    //变量压入栈
    lua_getglobal(lua_state, "width");
    lua_getglobal(lua_state, "height");

    if (!lua_isnumber(lua_state, -2))
    {
        luaL_error(lua_state, " 'width' should be a number\n ");
    }

    if (!lua_isnumber(lua_state, -1))
    {
        luaL_error(lua_state, " 'height' should be a number\n ");
    }

    *width = (int)lua_tonumber(lua_state, -2);
    *height = (int)lua_tonumber(lua_state, -1);

    lua_close(lua_state);
}

//调函数之前需要假设栈顶元素为一个有效的颜色 table
int getField(lua_State *lua_state, char *key)
{
    int result = 0;

    //压入元素
    lua_pushstring(lua_state, key);

    //将原来栈顶的元素弹出，以栈顶的值作为key来访问 - 2位置上的table 并将其值放入栈顶
    lua_gettable(lua_state, -2);// 第二个参数为 table 在栈中的位置参数

    if (!lua_isnumber(lua_state, -1))
    {
        luaL_error(lua_state, "invalid component in background color");
    }

    result = (int)lua_tonumber(lua_state, -1) * MAX_COLOR;

    lua_pop(lua_state, 1);

    return result;
}

void setWinBackgroundColor(char *fileName, int *r, int *g, int *b)
{
    lua_State *lua_state = luaL_newstate();
    luaL_openlibs(lua_state);

    if (luaL_loadfile(lua_state, fileName) || lua_pcall(lua_state, 0, 0, 0))
    {
        luaL_error(lua_state, "cannot run configuration fiile: %s", lua_tostring(lua_state, -1));
    }
    
    //将背景颜色压入栈
    lua_getglobal(lua_state, "background");
    if (!lua_istable(lua_state, -1))
    {
        luaL_error(lua_state, "'background' is not a valid color table");
    }

    *r = getField(lua_state, "r");
    *g = getField(lua_state, "g");
    *b = getField(lua_state, "b");

    lua_close(lua_state);
}

void testSetWndBackground()
{
    int _width = 0, _height = 0;
    setWinSize("Config.lua", &_width, &_height);
    printf("width = %d\n", _width);
    printf("height = %d\n", _height);

    int r = 0, g = 0, b = 0;
    setWinBackgroundColor("Config.lua", &r, &g, &b);
    printf("backgroundColor = (%d, %d, %d)\n", r, g, b);
}

//在应用中定义颜色
struct  ColorTable
{
    char *name;
    unsigned char red, green, blue;
}colortable[] =
{
    { "WHITE", MAX_COLOR, MAX_COLOR, MAX_COLOR },
    { "RED", MAX_COLOR, 0, 0 },
    { "GREEN", 0, MAX_COLOR, 0 },
    { "BLUE", 0, 0, MAX_COLOR },
    { "BLACK", 0, 0, 0 },
    { NULL, 0, 0, 0 }
};

void setfield(lua_State *L, char *key, int value)
{
    lua_pushstring(L, key);                            //key
    lua_pushnumber(L, (double)(value / MAX_COLOR));    //value
    //以栈顶元素作为 value,以栈顶的下一个元素作为 key，调用完成后弹出栈顶的两个元素
    lua_settable(L, -3);
}

void setcolor(lua_State *L, struct ColorTable *colTab)
{
    lua_newtable(L);   //创建一个新的 table，然后将其入栈
    setfield(L, "r", colTab->red);
    setfield(L, "g", colTab->green);
    setfield(L, "b", colTab->blue);
    lua_setglobal(L, colTab->name);  //将 table 出栈并将其赋给一个全局变量名
}

void registerAllColor(lua_State *L, struct ColorTable *colTab)
{
    int i = 0;
    while (colTab[i].name != NULL)
    {
        setcolor(L, &colTab[i++]);
    }
}

void testRegisterAllColor()
{
    lua_State *l = luaL_newstate();
    luaL_openlibs(l);
    registerAllColor(l, colortable);
    lua_close(l);
}

int _tmain(int argc, _TCHAR* argv[])
{
    testSetWndBackground();
    testRegisterAllColor();
    system("pause");
    return 0;
}