love2d.love/src/common/Variant.cpp

/**
* Copyright (c) 2006-2012 LOVE Development Team
*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
*    claim that you wrote the original software. If you use this software
*    in a product, an acknowledgment in the product documentation would be
*    appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
*    misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
**/

#include "Variant.h"
#include <common/StringMap.h>

namespace love
{
	extern StringMap<Type, TYPE_MAX_ENUM> types;

	love::Type extractudatatype(lua_State * L, int idx)
	{
		Type t = INVALID_ID;
		if (!lua_isuserdata(L, idx))
			return t;
		if (luaL_getmetafield (L, idx, "__tostring") == 0)
			return t;
		lua_pushvalue(L, idx);
		int result = lua_pcall(L, 1, 1, 0);
		if (result == 0)
			types.find(lua_tostring(L, -1), t);
		if (result == 0 || result == LUA_ERRRUN)
			lua_pop(L, 1);
		return t;
	}

	Variant::Variant(bool boolean)
	{
		type = BOOLEAN;
		data.boolean = boolean;
	}

	Variant::Variant(double number)
	{
		type = NUMBER;
		data.number = number;
	}

	Variant::Variant(const char *string, size_t len)
	{
		type = STRING;
		char *buf = new char[len+1];
		memset(buf, 0, len+1);
		memcpy(buf, string, len);
		data.string.str = buf;
		data.string.len = len;
	}

	Variant::Variant(char c)
	{
		type = CHARACTER;
		data.character = c;
	}

	Variant::Variant(void *userdata)
	{
		type = LUSERDATA;
		data.userdata = userdata;
	}

	Variant::Variant(love::Type udatatype, void *userdata)
	{
		type = FUSERDATA;
		this->udatatype = udatatype;
		if (udatatype != INVALID_ID)
		{
			Proxy *p = (Proxy *) userdata;
			flags = p->flags;
			data.userdata = p->data;
			((love::Object *) data.userdata)->retain();
		}
		else
			data.userdata = userdata;
	}

	Variant::~Variant()
	{
		switch(type)
		{
			case STRING:
				delete[] data.string.str;
				break;
			case FUSERDATA:
				((love::Object *) data.userdata)->release();
				break;
			default:
				break;
		}
	}

	Variant *Variant::fromLua(lua_State *L, int n)
	{
		Variant *v = NULL;
		size_t len;
		const char *str;
		switch(lua_type(L, n))
		{
			case LUA_TBOOLEAN:
				v = new Variant(luax_toboolean(L, n));
				break;
			case LUA_TNUMBER:
				v = new Variant(lua_tonumber(L, n));
				break;
			case LUA_TSTRING:
				str = lua_tolstring(L, n, &len);
				v = new Variant(str, len);
				break;
			case LUA_TLIGHTUSERDATA:
				v = new Variant(lua_touserdata(L, n));
				break;
			case LUA_TUSERDATA:
				v = new Variant(extractudatatype(L, n), lua_touserdata(L, n));
				break;
		}
		return v;
	}

	void Variant::toLua(lua_State *L)
	{
		switch(type)
		{
			case BOOLEAN:
				lua_pushboolean(L, data.boolean);
				break;
			case CHARACTER:
				lua_pushlstring(L, &data.character, 1);
				break;
			case NUMBER:
				lua_pushnumber(L, data.number);
				break;
			case STRING:
				lua_pushlstring(L, data.string.str, data.string.len);
				break;
			case LUSERDATA:
				lua_pushlightuserdata(L, data.userdata);
				break;
			case FUSERDATA:
				if (udatatype != INVALID_ID)
				{
					const char *name = NULL;
					love::types.find(udatatype, name);
					((love::Object *) data.userdata)->retain();
					luax_newtype(L, name, flags, data.userdata);
				}
				else
					lua_pushlightuserdata(L, data.userdata);
				// I know this is not the same
				// sadly, however, it's the most
				// I can do (at the moment).
				break;
			default:
				lua_pushnil(L);
				break;
		}
	}
} // love