将iconv编译成lua接口

前一篇博文说了。在cocos2dx中怎么样使用iconv转码，这节我们将上一节中写的转码函数，做成一个lua接口。在lua脚本中使用。

网上能够下载到luaconv。可是编译的时候总是报错，所以自己写了一接口。

一 加入lua接口文件

// luaiconv.h

#ifndef __LUA_ICONV_H__
#define __LUA_ICONV_H__

#include "tolua++.h"
#include "tolua_event.h"
#include "lauxlib.h"

#if CC_TARGET_PLATFORM == CC_PLATFORM_WIN32
#include "iconv.h"
#elif CC_TARGET_PLATFORM == CC_PLATFORM_IOS
#include <iconv.h>
#elif CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID
#include "iconv.h"
#endif

int tolua_iconv_open(lua_State *L);

#endif

//luaiconv.cpp

#include "luaiconv.h"
#include <stdlib.h>

#define MAX_STRING_SIZE 1024
#define TEST_STR ("Hello, 这是个转码測试字符串")

bool iconv_convert(void *src, unsigned int src_len,char *src_charset, void *dest, unsigned int dest_len, char *dest_charset)
{
	const char *in;
	char *out,*dest_ptr;
	size_t in_left,out_left,mutant,converted;

	in_left = src_len;
	out_left = dest_len;
	in = (char *)src;
	out = dest_ptr = (char *)dest;

	iconv_t oConv=iconv_open(dest_charset,src_charset);
	if(oConv==(iconv_t)(-1)){
		printf("XXXXXXXXXX ERROR: unable to open libiconv.\n");
		return false;
	}

	mutant = iconv(oConv, &in, &in_left, &out, &out_left );
	iconv_close(oConv);

	if(mutant == (size_t)(-1)){
		printf("XXXXXXXXXX ERROR: unable to convert anything.\n");
		return false;
	}
	converted = dest_len - out_left;
	dest_ptr[converted]='\0';

	printf("XXXXXXXXXX src string:%s\n", src);
	printf("XXXXXXXXXX to convert %u characters, %u mutanted , %u converted \n",src_len,mutant,converted);
	printf("XXXXXXXXXX dst string:%s\n", dest);

	return true;
}

void convertTest()
{
	char inStr[] = TEST_STR;
	char outStr[MAX_STRING_SIZE];
	iconv_convert(&inStr, sizeof(inStr), "GBK", &outStr, sizeof(outStr), "UTF-8");
	printf("XXXXXXXXXX in string:%s\n", inStr);
	printf("XXXXXXXXXX out string:%s\n", outStr);
}

TOLUA_API int luaiconv(lua_State *L)
{
	char *inbuf = (char*) luaL_checkstring(L, 1);
	char *src_charset = (char*) luaL_checkstring(L, 2);
	char *dst_charset = (char*) luaL_checkstring(L, 3);

	size_t ibleft = lua_strlen(L, 1);
	size_t obleft = (ibleft > 256) ? ibleft : 256;
	char *outbuf = (char*) malloc(obleft * sizeof(char));
    if (outbuf == NULL) {
        lua_pushstring(L, "");
        return 1;
    }

	if(!iconv_convert(inbuf, ibleft, src_charset, outbuf, obleft, dst_charset)){
		lua_pushstring(L, "");
		return 1;
	}

    lua_pushstring(L, outbuf);
    free(outbuf);

    return 1;
}

static luaL_Reg iconvlib[] = {
	{"luaiconv", luaiconv},
	{NULL, NULL}
};

// 函数名必须为luaopen_xxx，当中xxx表示library名称,Lua代码require "xxx"须要与之相应。
int luaopen_iconv(lua_State* L)
{
	const char* libName = "iconv";
	luaL_register(L, libName, iconvlib);// 调用方式libName.函数名

	return 1;
}

int tolua_iconv_open(lua_State *L)
{
	luaopen_iconv(L);
	return 1;
}

在AppDelegate中

#include "luaiconv.h"

然后在AppDelegate::applicationDidFinishLaunching()中调用：

CCLuaEngine* pEngine = CCLuaEngine::defaultEngine();
CCScriptEngineManager::sharedManager()->setScriptEngine(pEngine);
tolua_iconv_open(pEngine->getLuaStack()->getLuaState());

在lua中这样使用：

require "iconv"
iconv.luaiconv("string to convert code","GBK","UTF-8")

二 改动项目的Android.mk

LOCAL_SRC_FILES 中加上luaiconv.cpp

切记在末尾加上空格和续行符:" \"

否则有可能会报错：

make: *** No rule to make target
'xxx.o', needed by 'xxx'. Stop